Abstract:
Apparatus and method for determining: proper operation of a cleaning system, the depth of liquid in a drum, the predicted failure of a pump, improving the ability to monitor cleaning system, improving the ability to monitor dairy wash systems, improving the ability to monitor animal husbandry systems, and/or increasing the efficiency with which various types of equipment, fluid levels, and/or systems can be serviced or monitored.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and benefit of the following patent applications: (1) U.S. Provisional Patent Application 61/954,725, filed Mar. 18, 2014; and (2) U.S. Provisional Patent Application 61/932,334, filed Jan. 28, 2014; each of which is hereby incorporated by reference in its entirety as if fully set forth herein. 
     
    
     BACKGROUND 
       [0002]    The present invention is generally directed to sensors and, more specifically, to sensors adapted to determine the depth of liquid in a drum. 
         [0003]    It may be advantageous to provide a sensor that is preferably: simple to manufacture, relatively inexpensive to manufacture, relatively reliable, relatively easy to install, capable of determining the depth of liquid in a drum, capable of determining the volume of liquid in a drum, capable of knowing when liquid is being withdrawn from the drum instead of a non withdrawal event, capable of monitoring withdrawals over time and detecting trends or deviations from the norm so that gradual malfunctions or changes in use can be detected, and/or capable of sending alerts if the volume of liquid withdrawn from the drum is less than a predetermined volume. 
       SUMMARY 
       [0004]    Briefly speaking, one embodiment of the present invention is directed to a sensor apparatus for measuring a depth of a liquid in a drum. The sensor apparatus includes a tube that has first and second ends. The second end is configured for placement within the liquid. A seal is positioned in the tube and spaced from the second end. A first sensor is disposed in the tube between the seal and the second end and is configured to measure air pressure in the tube. The tube has an opening that allows liquid in the drum to partially fill the tube. A processor is in electronic communication with the first sensor. A second sensor is in electronic communication with the processor and is configured to measure atmospheric pressure outside of the drum. An outer tube is disposed over the tube, and, has third and fourth ends. The outer tube is configured to withdraw liquid from the drum when the sensor apparatus is inserted into a hole in a top of the drum. The processor is configured to automatically determine the depth of the liquid in the drum, according to: H=(P b −P a )/(PPIC*SG liquid ). P b  is the pressure in the drum at the opening of the tube as measured by the first sensor. P a  is the atmospheric pressure outside the drum as measured by the second sensor. SG liquid  is the specific gravity of the liquid inside the drum. H is the depth, or height, of the liquid inside the drum generally above the opening in the tube. PPIC is determined by ((H−TUBE liquidinches )*249.17)/H). TUBE liquidinches  is the height of liquid in the tube above the opening. And 249.17 is the standard pressure exerted by a one inch column of water. The processor is further configured to automatically determine a volume of the liquid in the drum while taking into account any adjustment needed due to the presence of the sensor apparatus therein. By using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, the processor automatically adjusts the initial volume of the liquid in the drum to get a final volume of liquid in the drum that takes into account the volume of the sensor apparatus, according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A). H is the depth of liquid in the drum generally above the opening in the tube. Vdrum-final is the final volume of liquid in the drum. Vdrum-initial is the initial volume of liquid in the drum. A is a cross sectional area of the tube. Dliquid-in-sensor is the depth of the liquid in the tube determined as follows: Dliquid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)). Wherein L is a length of the tube; Pi is the initial pressure in the tube prior to insertion of the tube in the liquid; Vi is the initial volume of the tube that is calculated by the dimensions of the tube; Ti is the initial temperature of air in the tube; Pf is a pressure in the tube when the tube is submerged in the liquid as calculated by the first sensor; and Tf is the final temperature of the air inside the tube when the tube is submerged. 
         [0005]    In a separate aspect, one embodiment of the present invention is directed to a sensor apparatus for measuring a depth of a liquid in a drum. The sensor apparatus comprises a tube that has first and second ends. The second end is configured for placement within the liquid. A seal is positioned in the tube and spaced from the second end. A first sensor is disposed in the tube between the seal and the second end and is configured to measure air pressure in the tube. A processor is in electronic communication with the first sensor. A second sensor is in electronic communication with the processor and is configured to measure atmospheric pressure outside of the drum. An outer tube is disposed over the tube, and, has third and fourth ends. The outer tube is configured to withdraw liquid from the drum when the sensor apparatus is inserted into a hole in a top of the drum. 
         [0006]    In a separate aspect, one embodiment of the present invention is directed to a sensor apparatus for measuring the depth of a liquid in a drum. The sensor apparatus comprises a tube having first and second ends. The second end is configured for placement within the liquid. A seal is positioned in the tube and spaced from the second end. A first sensor is disposed in the tube between the seal and the second end and is configured to measure atmospheric pressure in the tube. A processor is in electronic communication with the first sensor. A second sensor is configured to measure atmospheric pressure outside of the drum and is in electronic communication with the processor. 
         [0007]    In a separate aspect, one embodiment of the present invention is directed to a sensor apparatus for measuring the depth of a liquid in a drum. The sensor apparatus comprises a tube having first and second ends. A first sensor is disposed in the tube and is configured to measure atmospheric pressure in the tube. A processor is in electronic communication with the first sensor. 
         [0008]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprises the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor is an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a at least one software module stored on a non-transitory computer readable storage medium, the software module is configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal; providing a processor having at least one software module thereon; providing a tube including an opening therein, the opening configured to let the liquid in the drum partially fill the tube; the processor is configured to automatically determine the depth of the liquid in the drum according to: H=(P b −P a )/(PPIC*SG liquid ), where P b  is the pressure in the drum at the opening of the tube as measured by the first sensor, P a  is the atmospheric pressure outside the drum as measured by the second sensor, SG liquid  is the specific gravity of the liquid inside the drum, H is the depth, or height, of the liquid inside the drum, PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening, and 249.17 is the standard pressure exerted by a one inch column of water; the processor is configured to automatically determine a volume of the liquid in the drum while taking into account any adjustment needed due to the presence of the first sensor therein by using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the first sensor. 
         [0009]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprises the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor is an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a at least one software module stored on a non-transitory computer readable storage medium, the software module is configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal; providing a processor having at least one software module thereon. 
         [0010]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprises the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; providing a at least one software module stored on a non-transitory computer readable storage medium, the software module is configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal. 
         [0011]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprises the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum; providing a at least one software module stored on a non-transitory computer readable storage medium, the software module is configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the measurements of at least one of the first sensor and the second sensor. 
         [0012]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and/or animal husbandry. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; determining the depth of the liquid in the drum based on the first signal; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the first signal; providing a processor including the at least one software module thereon such that the processor automatically determines the depth of liquid in the drum; providing a tube having an opening therein, the opening configured to let the liquid in the drum partially fill the tube; the processor is configured to automatically determine the depth of the liquid in the drum according to: H=(P b −P a )/(PPIC*SG liquid ), where P b  is the pressure in the drum at the opening of the tube as measured by the first sensor, P a  is the atmospheric pressure outside the drum as measured by the second sensor, SG liquid  is the specific gravity of the liquid inside the drum, H is the depth, or height, of the liquid inside the drum, PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening, and 249.17 is the standard pressure exerted by a one inch column of water; the processor further being configured to automatically determine a volume of the liquid in the drum and taking into account any adjustment needed due to the presence of the first sensor therein by using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the first sensor. 
         [0013]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and animal husbandry. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; determining the depth of the liquid in the drum based on the first signal; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the first signal; providing a processor including the at least one software module thereon such that the processor automatically determines the depth of liquid in the drum. 
         [0014]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and/or animal husbandry. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; determining the depth of the liquid in the drum based on the first signal. 
         [0015]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a dairy wash system. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; determining the depth of the liquid in the drum based on the first signal; the dairy wash system performing a predetermined number of washes, the dairy wash system only withdrawing liquid from the drum during a wash; the processor being configured to collect a plurality of usage data comprising at least one of a time, a temperature of liquid withdrawn from the drum, and a volume of liquid withdrawn from the drum; the processor being configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. 
         [0016]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a dairy wash system. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; determining the depth of the liquid in the drum based on the first signal; the processor being configured to collect a plurality of usage data comprising at least one of a time, a temperature of liquid withdrawn from the drum, and a volume of liquid withdrawn from the drum; the processor being configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. 
         [0017]    In a separate aspect, one embodiment of the present invention is directed to a method for measuring a depth of a liquid in a drum used as part of a dairy wash system. The method comprising the steps of: providing the drum configured to contain the liquid used in the system; providing a first sensor located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; determining the depth of the liquid in the drum based on the first signal; the processor being configured to compare a plurality of data collected on the liquid in the drum against a plurality of predetermined data and issue an alert when a discrepancy occurs. 
         [0018]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a tube including an opening that is configured to let liquid in the drum partially fill the tube; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the first signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event; providing a processor including the at least one software module thereon, the processor receiving the first signal and automatically determining the depth of the liquid in the drum and automatically determining whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event; wherein the processor is configured to automatically determine the depth of the liquid in the drum according to: H=(P b −P a )/(PPIC*SG liquid ), where P b  is the pressure in the drum at the opening of the tube as measured by the first sensor, P a  is the atmospheric pressure outside the drum as measured by the second sensor, SG liquid  is the specific gravity of the liquid inside the drum, H is the depth, or height, of the liquid inside the drum, PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening, and 249.17 is the standard pressure exerted by a one inch column of water; the processor further being configured to automatically determine a volume of the liquid in the drum and take into account any adjustment needed due to the presence of the system therein by using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the system. 
         [0019]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event; providing a processor including the at least one software module thereon, the processor receiving the first signal and automatically determining the depth of the liquid in the drum and automatically determining whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event. 
         [0020]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum, the second sensor generating a second signal corresponding to ambient pressure outside the drum; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event. 
         [0021]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum, the second sensor being an air pressure sensor generating a second signal corresponding to ambient pressure outside the drum; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on at least one of the first signal and the second signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event; generating the first signal at a predetermined interval and the second sensor generating the second signal at the predetermined interval; the processor being configured to compile a report, the report being an average of the plurality of readings over a predetermined time; the processor being configured to store at least three of the reports, the at least three reports being the newest at least three reports compiled; the processor being configured to determine a pressure difference between at least two of the reports; the processor being configured to recognize the liquid withdrawal when the pressure difference between at least two of the reports is greater than a predetermined pressure; the processor being configured to determine a volume of the liquid withdrawn in the liquid withdrawal by analyzing the total pressure difference. 
         [0022]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum, the second sensor being an air pressure sensor generating a second signal corresponding to ambient pressure outside the drum; generating the first signal at a predetermined interval and the second sensor generating the second signal at the predetermined interval; providing a processor being configured to compile a report, the report being an average of the plurality of readings over a predetermined time; the processor being configured to store at least three of the reports, the at least three reports being the newest at least three reports compiled; the processor being configured to determine a pressure difference between at least two of the reports; the processor being configured to recognize a liquid withdrawal when the pressure difference between at least two of the reports is greater than a predetermined pressure; the processor being configured to determine a volume of the liquid withdrawn in the liquid withdrawal by analyzing the total pressure difference. 
         [0023]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a second sensor configured to be in fluid communication with ambient atmosphere outside of the drum, the second sensor being an air pressure sensor generating a second signal corresponding to ambient pressure outside the drum; providing a processor configured to recognize a liquid withdrawal when a change in pressure is greater than a predetermined amount; the processor being configured to determine a volume of the liquid withdrawn in the liquid withdrawal by analyzing the total pressure difference. 
         [0024]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor being an air pressure sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing a processor configured to recognize a liquid withdrawal when a change in pressure is greater than a predetermined amount; the processor being configured to determine a volume of the liquid withdrawn in the liquid withdrawal by analyzing the total pressure difference. 
         [0025]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the first signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event; providing a processor including the at least one software module thereon, the processor receiving the first signal and automatically determining the depth of the liquid in the drum and automatically determining whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event. 
         [0026]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: providing a first sensor configured to be located in fluid communication with an inside of the drum, the first sensor generating a first signal corresponding to the pressure of the liquid at a bottom of the drum; providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor, the processor is configured to automatically determine the depth of the liquid in the drum based on the first signal and to automatically determine whether a liquid withdrawal has occurred or whether changes in the first signal represent a non withdrawal event 
         [0027]    In a separate aspect, one embodiment of the present invention is directed to a method for providing a system for measuring a depth of a liquid in a drum. The method comprising the steps of: receiving data corresponding to the pressure of the liquid at a bottom of the drum; automatically determining the depth of the liquid in the drum based on the data and automatically determining whether a liquid withdrawal has occurred or whether changes in the data represent a non withdrawal event. 
         [0028]    In a separate aspect, one embodiment of the present invention is directed to providing at least one software module stored on a non-transitory computer readable storage medium, the software module containing instructions operable on a processor for automatically determining the depth of the liquid in a drum and to automatically determining whether a liquid withdrawal has occurred or whether a non withdrawal event has occurred. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The foregoing summary, as well as the following detailed description of the preferred embodiment of the present invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
           [0030]      FIG. 1  is a front view of a sensor apparatus in combination with a system for use with agriculture, cleaning, and/or animal husbandry according to a first preferred embodiment of the present invention; the sensor apparatus includes a tube having first and second ends; the second end of the tube is configured for placement within the liquid of the drum such that the second end rests against the bottom of the drum; although a preferred configuration of the seal is shown, those of ordinary skill in the art will appreciate from this disclosure that the seal may be at any location in the tube spaced from the second end without departing from the scope of the present invention; 
           [0031]      FIG. 2  is a front view of a sensor apparatus according to a first preferred embodiment of the present invention; the sensor apparatus may include a tube having first and second ends; the second end of the tube may be configured for placement within the liquid of the drum via a hole in the top of the drum such that the second end rests against the bottom of the drum; the tube may have a seal positioned at the first end, the seal being a printed circuit board; although a preferred configuration of the seal is shown, those of ordinary skill in the art will appreciate from this disclosure that the seal may be at any location in the tube spaced from the second end without departing from the scope of the present invention; a first sensor may be located on the printed circuit board such that the first sensor is between the printed circuit board and the second end, and, configured to measure air pressure in the tube; the tube may have an opening located in the second end; the opening allows the liquid in the drum partially fill the tube between the second end and the seal when the sensor apparatus is placed in the liquid; the area of the opening may be relatively small compared to the area of the second end, the area of the opening may be similar to the area of the second end, or, the area of the opening may be any size in between relatively small and similar to the area of the second end; the second end may be irregular in shape such that positioning of the second end on a flat bottom of the drum will not prevent flow of liquid into the tube; as shown, the second end of the tube has an angled second end with respect to the flat, horizontal bottom of the drum; although a preferred configuration of the second end is shown, those of ordinary skill in the art will appreciate from this disclosure that the second end may be rounded, have dimples or protrusions, or be any other suitable shape without departing from the scope of the present invention; the tube may contain a shield located between the second end and the seal; the shield may be configured to form a barrier between the first sensor and an inner surface of the tube such that a drop of the liquid is less likely to flow down the inner surface of the tube and contact the first sensor; the shield may be further configured to leave at least one air passageway between the first sensor and the second end so that the air pressure measurements of the first sensor are not impeded by the shield; the sensor apparatus may include a container positioned on the first end of the tube; the container may have an opening on at least one side such that the air pressure in the container is similar to the ambient air pressure around the drum; the container may also have a second sensor therein that is configure to measure the ambient air pressure outside the drum; however, the location of the second sensor may be any one of on the first end, between the seal and the first end, in a compartment attached to the tube, and spaced from the sensor apparatus without departing from the scope of the invention; preferably, the second sensor is located on a micro board, a printed circuit board, or the like; the first and second sensors may be connected by a wire to a processor, that is shown labeled in the Figures as a control box; the processor preferably includes a mini SD disk or the like, a battery backup or the like, and a cellular board; the processor may be configured to compute a volume of the liquid in the drum based on the measurements of the first sensor and the second sensor, and, also using a plurality of inputs representing at least one of a dimension of the drum, a dimension of the sensor apparatus, and a specific gravity of the liquid; the processor may be configured for entry of the plurality of inputs via a remote electronic device; the processor may be configured to automatically determine the depth of the liquid in the drum, according to: H=(P b −P a )/(PPIC*SG liquid ), where P b  is the pressure in the drum at the opening of the tube as measured by the first sensor, P a  is the atmospheric pressure outside the drum as measured by the second sensor, SG liquid  is the specific gravity of the liquid inside the drum, H is the depth, or height, of the liquid inside the drum generally above the opening in the tube, PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening, and 249.17 is the standard pressure exerted by a one inch column of water; the processor may be further configured to automatically determine the volume of the liquid in the drum and take into account any adjustment needed due to the presence of the sensor apparatus therein by using the depth of the liquid in the drum and dimensions of the drum to determine an initial volume of liquid in the drum, then the processor automatically adjusts the initial volume of liquid in the drum to get a final volume of liquid in the drum that takes into account the sensor apparatus, according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A), wherein H is the depth of liquid in the drum generally above the opening in the tube, Vdrum-final is the final volume of liquid in the drum, Vdrum-initial is the initial volume of liquid in the drum, A is a cross sectional area of the tube, Dliqid-in-sensor is the depth of the liquid in the tube determined as follows: Dliqid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)), wherein L is a length of the tube, Pi is the initial pressure in the tube prior to insertion of the tube in the liquid, Vi is the initial volume of the tube that is calculated by the dimensions of the tube, Ti is the initial temperature of air in the tube, Pf is a pressure in the tube when the tube is submerged in the liquid as calculated by the first sensor, and Tf is the final temperature of the air inside the tube when the tube is submerged; the processor may be configured to collect a plurality of usage data comprising at least one of a time and a temperature of liquid withdrawn from the drum; the processor may be configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs; a hose that is connected to a pump may also be placed within the drum to withdrawal liquid from the drum; the processor may be configured to determine whether a pressure drop as measured by one of the first sensor and the first and second sensors is a withdrawal of liquid or a non withdrawal event; the processor may further be configured to send an alert by text message if the volume of liquid withdrawn is less than a predetermined amount, thereby warning the owner or a third party that there is a problem with the liquid withdrawal setup; 
           [0032]      FIG. 3  is a front view of the sensor apparatus of  FIG. 2  including the outer tube; the tube may have an outer tube disposed over the tube; the outer tube having third and fourth ends and configured to withdraw the liquid from the drum when the sensor apparatus is inserted into the hole in the top of the drum; at least a portion of the tube may protrude from the fourth end of the outer tube so that withdrawal of the liquid from the drum via the outer tube does not create suction that seals the outer tube to a bottom of the drum; instead of a hose being inserted into the drum, the hose may be located on the outer tube and in fluid communication therewith such that liquid withdrawn from the drum via the outer tube then traverses the hose; having the hose on the outer tube reduces the number of steps needed to transfer the sensor apparatus and hose to another drum since the hose and the sensor apparatus are connected; the container that holds the second sensor and that is located on the first end of the tube may also form a second seal between the outer tube and the tube, and, the third end of the outer tube and the atmosphere; a first area defined by an axial cross section of the fourth end of the outer tube may be greater than a second area defined by an axial cross section of the third end of the outer tube; at least one device may be located within the fourth end and is configured to prevent the liquid in the outer tube from exiting the sensor apparatus between the tube and the outer tube via the fourth end when the sensor apparatus is withdrawn from the liquid in the drum; the at least one device may not prevent liquid from entering the outer tube through the fourth end; the second end of the tube may be located off-center in the fourth end of the outer tube in order to provide additional room for the operation of the at least one device; the at least one device may be a duck bill valve, although, those of ordinary skill in the art will recognize that the at least one device may be any other suitable device without departing from the scope of the invention; 
           [0033]      FIG. 4  is a cross sectional view of  FIG. 3  taken along the line  4 - 4 ; the cross section of the second end of the tube and the at least one device can be seen within the fourth end of the sensor apparatus; 
           [0034]      FIG. 5  is a second preferred embodiment of the sensor apparatus; in this embodiment, the seal may be located in the tube between the first and second ends; the seal may be a printed circuit board and the first sensor may be located on the seal between the seal and the second end; however, the first sensor may be located anywhere that is in fluid communication with the inside of the drum without departing from the scope of the invention; the second sensor may be located between the seal and the first end of the tube; a portion of the tube between the seal and the first end may have an opening therein such that the sensor is in fluid communication with ambient pressure outside the drum; however, those of ordinary skill in the art will recognize that the second sensor may be located anywhere that allows the second sensor to be in fluid communication with ambient pressure outside the drum, or, fluid communication with air inside the drum without departing from the scope of the present invention; the first and second sensors may generate first and second signals that correspond to the pressure of the liquid at the bottom of the drum and the ambient pressure outside the drum, respectively; the first sensor may have wires that extend therefrom that extend through the seal, the second seal, and run to the top of the container; the second sensor may wire that extend therefrom and extend through the second seal and run to the top of the container; the top of the container may have a main wire that transfers the first and second signals from the first and second sensors to the processor; however, the first and second signals may be transferred in any suitable way without departing from the scope of the invention; 
           [0035]      FIG. 6  is a third preferred embodiment of the sensor apparatus; in this embodiment, the second sensor may be located spaced from the sensor apparatus and may be located on the processor; 
           [0036]      FIGS. 7A and 7B  are a flow chart showing a preferred method used by the processor for an equipment wash on a dairy farm; however, those of ordinary skill in the art will recognize that the method may be used for any agricultural, equipment wash, or animal husbandry system without departing from the preferred embodiment; the processor is preferably configured to determine when a washing cycle has started and ended by first determining if the temperature recorded by a temperature sensor on a milk line has risen a predetermined number of degrees in a predetermined time period, therefore, meaning that the milking of cows is over; if the processor has determined that the temperature of the milk line has risen a predetermined number of degrees within a predetermined time period, the processor is preferably configured to start storing readings of the pressure measured by at least one sensor apparatus; preferably, the processor is further configured to start compiling reports for each sensor apparatus; preferably, the processor is preferably configured to store the newest of at least two reports for every liquid used in the washing cycle; more preferably, the processor is configured to store the newest of at least three reports for every liquid used in the washing cycle; more preferably still, the processor is configured to store the newest five reports for every liquid used in the washing cycle; preferably, the processor is further configured to analyze the stored reports for each liquid; preferably, the processor determines whether a liquid withdrawal has started in any of the liquids used in the washing cycle; if so, the processor is preferably configured to determine that a withdrawal of the respective liquid has just started; if not, the processor preferably starts the determination again when a new report is compiled; preferably, the processor is configured to determine a wash cycle has begun when the processor determines that the first withdrawal of any of the liquids; preferably, the processor preferably records the time that the processor determined a washing cycle has started, and, the number of washing cycles performed each day; after a liquid withdrawal has occurred for any of the liquids, the processor preferably is configured to determine when the liquid withdrawal has ended for the same liquid; after determining a liquid withdrawal for a particular liquid has ended, the processor is preferably configured to immediately determine the pressure drop of the liquid at the bottom of the drum; subsequently, the processor is preferably configured to determine the order that each liquid&#39;s withdrawal ended; after the processor determines that a withdrawal has started on at least one liquid, the processor may be configured to start a timer such that if the processor fails to determine that the liquid withdrawal has ended for all liquids within a predetermined length of time, the processor may reverse its determination that a withdrawal has taken place; after a liquid withdrawal for each liquid has ended, and, the order in which the liquids were withdrawn has been determined, the processor is preferably configured to perform another check to ensure a washing cycle, and liquid withdrawals, have indeed taken place; the check preferably includes the processor configured to determine if at least four of following have occurred: the processor has determined a wash cycle has started, the order in which the processor determined the liquid withdrawals occurred matches the order in which the liquids are to be withdrawn that was entered into the processor, if the pressure at the bottom of each drum has dropped by thirty or more Pascal&#39;s, if the temperature recorded by a temperature sensor on the milk line has risen or dropped a predetermined number of degrees in a predetermined time period, and if the temperature sensors on each hose are consistent with predetermined temperatures; if at least four have occurred, the processor is preferably configured to confirm the washing cycle; subsequently, the processor is preferably configured to send an alert if any data collected by the processor, such as temperature of the liquids flowing through the hose, the time of a washing cycle, or a pressure differential at the bottom of the drums after a liquid withdrawal has occurred, is inconsistent with a plurality of predetermined data; if less than four have occurred, the processor preferably reverses its determination that the washing cycle has started; subsequently, the processor preferably begins analyzing the stored reports again; 
           [0037]      FIG. 8  is a flow chart showing a second preferred method for providing a system for measuring a depth of a liquid in a drum; 
           [0038]      FIG. 9  is a flow chart showing a third preferred method for providing a system for measuring a depth of a liquid in a drum; 
           [0039]      FIGS. 10A and 10B  are a flow chart showing a fourth preferred method for providing a system for measuring a depth of a liquid in a drum; 
           [0040]      FIG. 11  is a flow chart showing a fifth preferred method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and animal husbandry; 
           [0041]      FIG. 12  is a flow chart showing a sixth preferred method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and animal husbandry; 
           [0042]      FIGS. 13A and 13B  are a flow chart showing a seventh preferred method for measuring a depth of a liquid in a drum used as part of a system for use in at least one of agricultural, equipment cleaning, and animal husbandry; 
           [0043]      FIG. 14  is a flow chart showing an eighth preferred method for providing a system for measuring a depth of a liquid in a drum; 
           [0044]      FIG. 15  is a flow chart showing a ninth preferred method for providing a system for measuring a depth of a liquid in a drum; and 
           [0045]      FIGS. 16A and 16B  are a flow chart showing a tenth preferred method for providing a system for measuring a depth of a liquid in a drum; 
           [0046]      FIG. 17  is a fourth preferred embodiment of the sensor apparatus; the sensor apparatus, similar to that shown in  FIG. 5 , may be spaced from the drum with a portion of the tube fixed to the drum; the second end of the tube may be disposed on the sidewall of the drum such that the tube and an inside of the drum are in fluid communication; preferably, the second end of the tube is on a portion of the tube that is perpendicular to a vertical sidewall; those of ordinary skill in the art will appreciate that the portion of the tube may be at any angle with respect to the vertical sidewall without departing from the scope of the present invention; the processor may be able to calculate the height of the liquid in the drum above the opening; preferably, the height of the liquid in the drum is from an effective location to the surface of the liquid in the drum; while the effective location of the embodiment disclosed in  FIG. 17  is located at a maximum height of the opening with respect to the bottom of the drum, those of ordinary skill in the art will appreciate that the effective location may be at a different location and may be changed due to a change of the angle of the portion of the tube with respect to a vertical sidewall and/or the shape of the opening without departing from the scope of the present invention; the processor may use the height of liquid in the drum along with the dimensions of the drum to determine an initial volume of liquid in the drum above effective location; preferably, the processor takes into account the vertical distance between the effective location and the bottom of the drum in order to calculate a finial height of the liquid in the drum that can be used to calculate the total volume of liquid in the drum, or, the processor may determine the volume of liquid below the effective location of the drum based on the drums dimensions and add this volume to the initial volume in the drum to calculate the total volume of liquid in the drum; preferably, the processor is configured to determine the volume of liquid in the tube so that the processor may determine a final volume of liquid by adding the volume of liquid in the tube to the total volume of liquid in the drum; the drum may have a hose connected to the bottom of the drum; however, those of ordinary skill in the art will appreciate that the hose may be located at any point on the drum without departing from the scope of the present invention; the hose may be connected to a pump and configured to withdrawal liquid from the drum; however, more sophisticated systems, such as some advanced hoofbath systems, may operate without any pump or electronics and instead operate based on fluid pressures and vacuums in a generally closed circuit type of arrangement; the drum may be located on a stand to give the drum more stability, especially if the drum  24  does not have a flat bottom; 
           [0047]      FIG. 18  is view of the graphic user interface (GUI) of the processor; the GUI may be located on the processor or may be accessible online or by the use of an electronic device; the GUI preferably has the name of the dairy farm, or other business, at the top; under the name, the GUI may have the current date and time; below the date and time, the GUI may have pictures of drums showing the depth of the liquid in the drum; underneath the pictures of the drums, the GUI preferably lists the liquid in each drum along with the volume of the liquid in the drum, the pump status, and the weeks until pump failure; the GUI may indicate that the pump has not reached its minimum volume threshold level for a wash by showing an “X” next to pump status; if the pump has met the minimum volume threshold, the GUI may indicate the pump is okay by showing a checkmark next to pump status; to the left of the pictures of the drums, the GUI may have a contact dealer button and a contact service provider button that, when pressed, automatically contact the dealer and service provider, respectively, either by a call, text, email, or the like; the GUI may also have a contacts button that allows a user to view and contact all stored contacts; at the bottom of the GUI may be a bunch of buttons such as buttons that may allow a user to view valve status, view current alerts, view wash history, view alert and reply history, maintenance log, and a button to stop wash immediately; however those of ordinary skill in the art will recognize that the GUI may include any suitable data, information, artwork, phrases, numbers, words, letters, or the like, in any arrangement without departing from the scope of the invention; 
           [0048]    FIGS.  19 A 1 - 19 A 3 ,  19 B- 190 ,  19 P 1 - 19 P 4 , and  19 Q are a preferred schematic for the processor; 
           [0049]    FIGS.  19 AA 1 - 19 AA 3 ,  19 BB- 19 OO,  19 PP 1 - 19 PP 4 , and  19 QQ are a second preferred schematic for the processor; 
           [0050]      FIG. 20  is a preferred schematic for the first sensor; 
           [0051]      FIGS. 21A-21N  are a preferred schematic for the second sensor or microprocessor that the second sensor is located on; 
           [0052]      FIG. 22  is a flowchart illustrating one preferred method for providing a sensor apparatus for measuring a depth of a liquid in a drum above an initial drum liquid height. 
           [0053]      FIG. 23  is a screenshot of a sample GUI showing text messages between the processor and a person; a person may ask the processor a text inquiry and the processor may send a text inquiry reply answering the text inquiry; a person may ask the processor to send a text inquiry reply related to certain information pertaining to the liquid in the drum, such as, the volume of liquid in each drum, the temperature of the liquids in each drum, etc.; also shown is a text alert from the processor; shown is a text alert informing at least one predetermined person that a liquid did not dispense during a wash. Those of ordinary skill in the art will appreciate from this disclosure that similar error, inquiry, reply, and reminder messages or the like can be communicated via voice simulation and voice recognition or any other suitable communications means without departing from the scope of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0054]    Certain terminology is used in the following description for convenience only and is not limiting. The term “fluid communication between A and B” means that A and B are located such that a fluid, such as air or liquid, may flow from A to B. For example, A and B are in fluid communication if A and B are sitting on an empty desk since air may freely flow from A to B. As another example, A and B may be in fluid communication with each other if A is sitting on a desk and B is located in a box containing a hole on the desk since air can still flow from A into the box, via the hole, to B. As yet another example, A and B may not be in fluid communication if A is sitting on a desk and B is located in an airtight box on the desk since air may not be able to flow from A into the box. The term “electronic device” refers to any device that manipulates electron flow for its operation, such as, a cell phone, tablet, device connected via the Internet, smart phone, keypad, computer, or the like. The word “drum” as used in the claims and in associated portions of the specification, means “any object configured to hold liquid therein such as a drum, barrel, tote, tub, tank, bath, holding tank, container, vat, and/or the like”. The language “at least one of ‘A’, ‘B’, and ‘C’,” as used in the claims and/or in corresponding portions of the specification, means “any group having at least one ‘A’; or any group having at least one ‘B’; or any group having at least one ‘C’; —and does require that a group have at least one of each of ‘A’, ‘B’, and ‘C’.” Additionally, the words “a” and “one” are defined as including one or more of the referenced item unless specifically stated otherwise. The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. 
         [0055]    Referring to  FIGS. 2-4 , wherein like numerals indicate like elements throughout, there is shown a preferred embodiment of a sensor apparatus  20  for measuring a depth of a liquid  22  in a drum  24 . The sensor apparatus  20  preferably includes a tube  26  that has first and second ends  28 A,  28 B wherein the second end  28 B may be configured for placement within the liquid  22 . While the tube  26  preferably has a circular cross-section when taken generally perpendicular to a longitudinal axis thereof, Those of ordinary skill in the art will appreciate from this disclosure that the tube cross section can be triangular, square, polygonal, irregular, or the like without departing from the scope of the present invention. 
         [0056]    The sensor apparatus  20  may be configured for insertion into the liquid  22  via a hole  42  in a top  40  of the drum  24 . It is preferable, although not required, that the second end  28 B be configured to rest against the bottom of the drum  24 . The second end  28 B may have an opening  36  therein to let liquid  22  in the drum  24  partially fill the tube  26  when the second end  28 B is placed within the liquid  22  in the drum  24 . To assure flow of liquid  22  into the tube  26  through the opening  36  in the second end  28 B, the second end  28 B may be irregular in shape such that positioning of the second end  28 B on a flat bottom of the drum  24  will not prevent flow of liquid  22  into the tube  26 . Said another way, the surface of the second end  28 B of the tube  26  may have a different contour than the bottom of the bottom of the drum  24  such that when the second end  28 B is resting on the bottom of the drum  24 , at least a portion of the second end  28 B is not in contact with the bottom of the drum  24 . While the opening  36  in the preferred embodiment has an area similar to the area of the second end  28 B, those of ordinary skill in the art will appreciate from this disclosure that the area of the opening  36  may be any value smaller than the area of the second end  28 B without departing from the scope of the present invention. Those of ordinary skill in the art will also appreciate from this disclosure that the second end  28 B may have multiple openings therein without departing from the scope of the present invention. Those of ordinary skill in the art will also appreciate from this disclosure that the opening  36  may not be in the second end  28 B, but may be located on a portion of the tube  26  spaced from the second end  28 B without departing from the scope of the present invention. 
         [0057]    Referring to  FIGS. 2 and 3 , a seal  30  may be positioned in the tube  26  and spaced from the second end  28 B. The seal  30  preferably is an air-tight seal. Preferably, the seal  30  is located on the first end  28 A of the tube  26 . However, as seen in  FIG. 5 , the seal  30  may be positioned between the first and second ends  28 A,  28 B of the tube  26 . In the preferred embodiment, the seal  30  is a printed circuit board that forms an air-tight seal, however, the seal  30  may be any suitable material without departing from the scope of the invention. 
         [0058]    The sensor apparatus  20  preferably includes a first sensor  32 A located between the second end  28 B and the seal  30  to measure the air pressure of the tube  26  between the seal  30  and the second end  28 B. While the preferred embodiment has the first sensor  32 A connected to the seal  30 , the first sensor  32 A may be located at any location such that the first sensor  32 A is in fluid communication with the air in the tube  26  between the seal  30  and the second end  28 B. Referring to  FIG. 20 , a preferred schematic of the first sensor  500  is shown. The illustrated schematic for the first sensor  500  is exemplary only. Those of ordinary skill in the art will appreciate from this disclosure that any suitable circuit(s) can be used without departing from the scope of the present invention. 
         [0059]    Still referring to  FIGS. 2 and 3 , the sensor apparatus  20  may include a shield  38  located between the second end  28 B and the seal  30 . The shield  38  is preferably configured to form a barrier between the first sensor  32 A and an inner surface of the tube  26  such that, when the sensor apparatus  20  is laid on its side or transported to another location, a drop of liquid  22  is less likely to flow along the inner surface of the tube  26  and contact the first sensor  32 A. While the preferred embodiment of the sensor apparatus  20  has a conically shaped shield  38  extending from the first end  28 A of the tube  26 , those of ordinary skill in the art will recognize that the shield  38  can have any suitable shape that impedes the flow of liquid  22  down the inner surface of the tube  26  without departing from the scope of the invention. Preferably, but not necessarily, the shield  38  is configured to leave at least one air passageway  52  between the first sensor  32 A and the second end  28 B so that the air pressure measurements of the first sensor  32 A are not altered by the shield  38 . 
         [0060]    The sensor apparatus  20  may also include, but is not required to include, a second sensor  32 B that is configured to measure atmospheric pressure outside the drum  24  or the pressure of the air inside the drum  24  and above the liquid  22 . While the preferred embodiment shows the second sensor  32 B located in container  50  attached to the first end  28 A of the tube  26 , the second sensor  32 B may be located at any one of on the first end  28 A, between the seal  30  and the first end  28 A, in a compartment attached to the tube  26 , and spaced from the sensor apparatus  20  without departing from the scope of the invention. The second sensor is preferably located on a microprocessor that is in electronic communication with the second sensor and the first sensor. Those of ordinary skill in the art will appreciate from this disclosure that instead of the second sensor, an assumed atmospheric pressure value can be used, a general pressure reading provided by an online, cellular, televised, or physical paper news source can be used without departing from the scope of the present invention. Referring to  FIGS. 21A-21N , a preferred schematic of the second sensor or the microprocessor that the second sensor is located on  600 A,  600 B, and  600 C is shown. The illustrated schematic for the second circuit  600 A,  600 B,  600 C is exemplary only. Those of ordinary skill in the art will appreciate from this disclosure that any suitable circuit(s) can be used without departing from the scope of the present invention. 
         [0061]    As best seen in  FIG. 3 , the sensor apparatus  20  may include an outer tube  44  disposed over the tube  26  wherein the outer tube  44  has third and fourth ends  46 A,  46 B and may be configured to withdraw liquid  22  from the drum  24  when the sensor apparatus  20  is inserted into the hole  42  in the top  40  of the drum  24 . The outer tube  44  may be, but need not be, sealed to the tube  26  at a location on the tube  26  spaced from the second end  28 B. At least a portion of the tube  26  may protrude from the fourth end  46 B of the outer tube  44  so that withdrawal of the liquid  22  from the drum  24  via the outer tube  44  does not create suction that seals the outer tube  44  to a bottom of the drum  24 . A hose  48  may be located on, or connected to, the outer tube  44  and in fluid communication therewith such that liquid  22  withdrawn from the drum  24  via the outer tube  44  then traverses the hose  48 . The hose  48  may be connected to a pump  54  in order to create the pressure differential needed for the outer tube  44  to withdrawal liquid  22  from the drum  24 . The outer tube  44  may have a protrusion extending therefrom that the outer tube  44  may be located on, or connected to. However, those of ordinary skill in the art will recognize from this disclosure that the hose  48  may be connected to the outer tube  44  in any suitable way, or at any location on the outer tube  44 , location without departing from the scope of the invention. A first area defined by an axial cross section of the fourth end  46 B of the outer tube  44  may be greater than a second area defined by an axial cross section of the third end  46 A of the outer tube  44 . At least one device  68  may be located within the fourth end  46 B and configured to prevent the liquid  22  in the outer tube  44  from exiting the sensor apparatus  20  between the tube  26  and the outer tube  44  via the fourth end  46 B when the sensor apparatus  20  is withdrawn from the liquid  22  in the drum  24 . The at least one device  68  allows the sensor apparatus  20  to be withdrawn from the drum  24  and placed back in the liquid  22  in the drum  24 , or another drum, without having to re-prime the outer tube  44  in order for the pump  54  to function properly. The at least one device  68  preferably allows the liquid  22  to entering the outer tube  44  through the fourth end  46 B. The at least one device  68  may be a duck bill valve. However, those of ordinary skill in the art will recognize that the one device  68  may be any suitable device without departing from the scope of the invention. As best shown in  FIGS. 3 and 4 , the second end  28 B of the tube  26  may located off-center in the fourth end  46 B of the outer tube  44  in order to provide additional room for the operation of the at least one device  68 . Duck bill valves, and other similar devices, may not work properly if they contact other instruments or parts. Therefore, the additional room created by locating the second end  28 B off-center in the fourth end  46 B of the outer tube  44  may allow the at least one device  68  to function unimpeded. The use of the at least one device  68  provides the advantage of preventing liquid from draining out of the sensor apparatus and connected hose when the sensor apparatus is removed from the drum. This facilitates use of the sensor apparatus with pumps that are not self priming. 
         [0062]    A container  50  is preferably, but not necessarily, positioned on the first end  28 A of the tube  26 . As described above, the container  50  preferably, but not necessarily, contains the second sensor  32 B. The container  50  may have a second opening  64  therein in to allow the second sensor  32 B to be in fluid communication with the ambient air outside the drum  24 . The second opening  64  may be relatively small compared to a side of the container  50 , however, those of ordinary skill in the art will recognize that there may be one or more openings that may be any size in relation to the container  50  without departing from the scope of the invention. As seen in  FIGS. 5 and 6 , if the second sensor  32 B is in a location other than the container  50 , or there is no second sensor in the sensor apparatus  20 , the container  50  need not have an opening thereon. As best seen in  FIG. 5 , if the second sensor  32 B is located in the tube  26  between the first end  28 A and the seal  30 , the tube  26  may have a third opening  66  therein such that the second sensor  32 B is in fluid communication with the ambient air outside the drum  24 , or, the air inside the drum  24 . The container  50  on the first end  28 A of the tube  26  may form a second seal  62  between the outer tube  44  and the tube  26 , and, the third end  46 A of the outer tube  44  and the atmosphere. It is preferable that that the third end  46 A of the outer tube  44  be sealed off from the atmosphere so that the pump  54  may function properly. 
         [0063]    Referring to  FIGS. 2 and 3 , the first and second sensors  32 A,  32 B may be in electronic communication with a processor  34 . The first and second sensors  32 A,  32 B may be electrically connected to a cable  56  located on top of the container  50 . As seen in  FIG. 5 , the first sensor  32 A may have at least one wire  58  extending therefrom that extends through the seal  30 , through the first end  28 A, and connected to the second sensor  32 B, or alternatively, the microprocessor. The second sensor  32 B may have at least one wire  60  that extends to the top of the container  50 . Referring to  FIGS. 2 ,  3 , and  5 , the top of the container  50  may be configured for the installation of an Ethernet jack, or the like, therein that may be configured for insertion of an Ethernet cable  56 , or the like. The cable  56  may extend from the top of the container  50  may electrically connect the first and second sensors  32 A,  32 B to the processor  34 . Alternatively, communications via the first or second sensor and a processor can be accomplished wirelessly or by any other suitable method. In some instances the processor referred to in the drawings may actually be a user&#39;s cell phone or computer that is connected via the Internet, wirelessly, or via a wifi network to the sensors. Alternatively, data can be stored on the sensor apparatus and manually withdrawn for analysis. At least one of the cable  56  and the container  50  may have a predetermined color such that if multiple sensor apparatus&#39;s are being used and connected to the same processor  34 , it would be easy for a user to determine the cable  56  connected to a specific sensor apparatus  20 . Although, those of ordinary skill in the art will recognize from this disclosure that the first and second sensors  32 A,  32 B may be electrically connected to the processor  34  in any suitable way without departing from the scope of the invention. Referring to FIGS.  19 A 1 - 19 A 3 ,  19 B- 190 ,  19 P 1 - 19 P 4 , and  19 Q, a preferred schematic of the processor  300 A,  300 B is shown. The preferred schematic of the processor  300 A,  300 B discloses a four channel controller. Referring to FIGS.  19 AA 1 - 19 AA 3 ,  19 BB- 19 OO,  19 PP 1 - 19 PP 4 , and  19 QQ, a second preferred schematic of the processor  400 A,  400 B is shown. The second preferred schematic of the processor  400 A,  400 B discloses a six channel controller. The illustrated schematics for the processor  300 A,  300 B,  300 C,  300 D are exemplary only. Those of ordinary skill in the art will appreciate from this disclosure that any suitable circuit(s) can be used without departing from the scope of the present invention. 
         [0064]    The processor  34  may be configured to compute a volume of the liquid  22  in the drum  24  based on the measurements of the first sensor  32 A and the second sensor  32 B, and, also using a plurality of inputs representing at least one of a dimension of the drum  24 , a dimension of the sensor apparatus  20 , and a specific gravity of the liquid  22 . The processor  34  may be configured for entry of the plurality of inputs via a remote electronic device. The remote electronic device may be a cell phone, a computer, a tablet, a website, or any other suitable way. The processor  34  may be configured to automatically determine the depth of the liquid  22  in the drum  24 , according to: H=(P b −P a )/(PPIC*SG liquid ), wherein P b  is the pressure in the drum  24  at the opening  36  of the tube  26  as measured by the first sensor  32 A, P a  is the atmospheric pressure outside the drum  24  as measured by the second sensor  32 B, SG liquid  is the specific gravity of the liquid inside the drum  24 , H is the depth, or height, of the liquid inside the drum  24  above the opening  36 , PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), TUBE liquidinches , or TL in the Figures, is the height of liquid  22  in the tube above the opening  36 , and 249.17 Pascals is the standard pressure exerted by a one inch column of water. however Those of ordinary skill in the art will appreciate from this disclosure that the precise pressure of one inch of water may vary due to circumstance without departing from the scope of the present invention. The processor  34  may be further configured to automatically determine the volume of the liquid  22  in the drum  24  and take into account any adjustment needed due to the presence of the sensor apparatus  20  therein. By using the depth of the liquid  22  in the drum  24  and the dimensions of the drum  24  to determine an initial volume of liquid  22  in the drum  24 , the processor  34  may automatically adjust the initial volume of liquid  22  in the drum  24  to get a final volume of liquid  22  in the drum  24  that takes into account the sensor apparatus  20 , according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A), wherein H is the depth of liquid in the drum  24 ; Vdrum-final is the final volume of liquid in the drum; Vdrum-initial is the initial volume of liquid in the drum  24 ; A is a cross sectional area of the tube  26 ; Dliquid-in-sensor is the depth of the liquid in the tube  26  generally above the opening in the tube determined as follows: Dliquid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)), wherein L is a length of the tube  26 ; Pi is the initial pressure in the tube  26  prior to insertion of the tube  26  in the liquid; Vi is the initial volume of the tube  26  that is calculated by the dimensions of the tube  26 ; Ti is the initial temperature of air in the tube  26 ; Pf is a pressure in the tube  26  when the tube  26  is submerged in the liquid as calculated by the first sensor  32 A; and Tf is the final temperature of the air inside the tube  26  when the tube  26  is submerged. 
         [0065]    While a preferred method of calculating liquid volumes and heights is disclosed above, those of ordinary skill in the art will appreciate from this disclosure that any other suitable calculation method or system can be used without departing from the scope of the present invention. 
         [0066]    The processor  34  may be configured to collect a plurality of usage data comprising at least one of a time and a temperature of liquid  22  withdrawn from the drum  24 . However other usage data may be collected such as duration of the withdrawal of liquid  22  from the drum  24 , and, total volume of liquid  22  withdrawn from the drum  24  without departing from the scope of the invention. The processor  34  may further be configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. The alert may be issued by any electronic means, such as a text, a phone call, an email, an alarm or any audible sound, a flashing light or any visual alert, or any other suitable way. 
         [0067]      FIG. 17  shows an alternative embodiment of the sensor apparatus  20 . The sensor apparatus  20 , similar to that shown in  FIG. 5 , may be spaced from the drum  24  with the second end  28 B of the tube  26  preferably disposed on the sidewall  24 A of the drum  24  such that the tube  26  and an inside of the drum are in fluid communication. Said another way, the tube  26  is not located in, or configured for placement in, the drum  24 . Instead, the tube  26  may be attached, or detachably connected, to a sidewall  24 A of the drum  24 . Preferably, the second end of the tube is on a portion  28 D of the tube  26  that is perpendicular to a vertical sidewall  24 A. Those of ordinary skill in the art will appreciate that the portion  28 D of the tube  26  may be at any angle with respect to the vertical sidewall  24 A without departing from the scope of the present invention. 
         [0068]    The processor  34  may be able to calculate the height H of the liquid  22  in the drum above the opening  36 . Preferably, the height H of the liquid  22  in the drum  24  is from an effective location  28 C to the surface of the liquid  22  in the drum  24 . While the effective location  28 C of the embodiment disclosed in  FIG. 17  is located at a maximum height of the opening  36  with respect to the bottom of the drum  40 A, those of ordinary skill in the art will appreciate that the effective location  28 C may be at a different location and may be changed due to a change of the angle of the portion  28 D of the tube  26  with respect to a vertical sidewall  24 A and/or the shape of the opening  36  without departing from the scope of the present invention. The processor  34  may use the height H of liquid  22  in the drum  24  along with the dimensions of the drum  24  to determine an initial volume of liquid in the drum above the opening  36 . Preferably, the processor  34  takes into account the initial liquid height ILH, which is the vertical distance between the effective height  28 C and the bottom of the drum  40 A in order to calculate a finial height of the liquid  22  in the drum  24  that can be used to calculate the total volume of liquid  22  in the drum  24 . Alternatively, the processor  34  may determine, or the information be inputted, the volume of liquid  22  below the effective height  28 C, and, add this volume to the initial volume in the drum  24  to calculate the total volume of liquid  22  in the drum  24 . Preferably, the processor  34  is configured to determine the volume of liquid in the tube to further determine a final volume of liquid by adding the volume of liquid in the tube to the total volume of liquid in the drum. 
         [0069]    The drum  24  may be located on a stand  24 B to give the drum more stability, especially if the drum  24  does not have a flat bottom  40 A. The drum  24  may have a hose  48  connected to the bottom of the drum  24  that may pass through the stand  24 B. However, those of ordinary skill in the art will appreciate that the hose  48  may be located at any point on the drum  24  without departing from the scope of the present invention. The hose  48  may be connected to a pump  54  and configured to withdrawal liquid  22  from the drum  24 . However, more sophisticated systems, such as some advanced hoofbath systems, may operate without any pump  54  or electronics and instead operate based on fluid pressures and vacuums in a generally closed circuit type of arrangement. This type of advanced hoofbath system is detailed in U.S. Pat. No. 8,347,821 which is hereby incorporated by reference in its entirety as if fully set forth herein. 
         [0070]    Preferred implementations of preferred methods of the present invention will be described below (alone or in combination with various embodiments of the sensor apparatus  20 ). The steps of the method of the present invention can be performed in any order, omitted, or combined without departing from the scope of the present invention. As such, optional or required steps described in conjunction with one implementation of the method can also be used with another implementation or omitted altogether. Additionally, unless otherwise stated, similar structure or functions described in conjunction with the below method preferably, but not necessarily, operate in a generally similar manner to that described elsewhere in this application. 
         [0071]    Referring to  FIGS. 8-10 , one method according to the present invention is directed to a method of providing a system for measuring a depth of a liquid  22  in a drum  24 . The method preferably includes providing a first sensor  32 A configured to be located in fluid communication with an inside of the drum  24 . The first sensor  32 A preferably is an air pressure sensor that generates a first signal corresponding to the pressure of the liquid  22  at a bottom of the drum  24 . The method preferably includes the step of providing a second sensor  32 B that is configured to be in fluid communication with ambient atmosphere outside of the drum  24 . Wherein the second sensor  32 B may be an air pressure sensor that generates a second signal corresponding to ambient pressure outside the drum  24 . The method may include the step of providing a tube  26  having a first end and a second end  28 A,  28 B, wherein the second end  28 B is configured for placement within the liquid  22 . The tube  26  may include a seal  30  positioned in the tube  26  and spaced from the second end  28 B, wherein the first sensor  32 A is configured to be located between the seal  30  and the second end  28 B. The method may include the step of configuring the second sensor  32 B to be located at any one of on the first end  28 A of the tube  26 , between the seal  30  and the first end, in a compartment attached to the tube  26 , and spaced from the system. The method may include the step of providing an opening  36  located in the second end  28 B of the tube  26  and configured to let the liquid  22  in the drum  24  partially fill the tube  26  between the second end  28 B and the seal  30 . The method may include the step of providing a shield  38  configured to be located between the second end  28 B and the seal  30 , wherein the is preferably configured to form a barrier between the first sensor  32 A and an inner surface of the tube  26  such that a drop of the liquid  22  is less likely to flow down the inner surface of the tube  26  and contact the first sensor  32 A. The method may further comprise an outer tube  44  having third and fourth ends  46 A,  46 B disposed over the tube  26  and configured to withdraw the liquid  22  from the drum  24  when the system is inserted into a hole  42  in a top  40  of the drum  24 . The third end  46 A of the outer tube  44  may be sealed to the tube  26  at a location on the tube  26  spaced from the second end  28 B. The method may include a container  50  positioned on the first end  28 A of the tube  26 , wherein, the container  50  houses the second sensor  32 B therein and forms a second seal  62  between the outer tube  44  and the tube  26 , and, the third end  46 A of the outer tube  44  and the atmosphere. The method may comprise placing at least one device  68  within the fourth end  46 B such that the at least one device  68  preferably is designed to prevent the liquid  22  in the outer tube  44  from exiting the system between the tube  26  and the outer tube  44  via the fourth end  46 B when the sensor apparatus  20  is withdrawn from the liquid  22  in the drum  24 . Preferably, the at least one device  68  is configured to allow the liquid  22  to enter the outer tube  44  through the fourth end  46 B. The method may comprise of configuring at least a portion of the tube  26  to protrude from the fourth end  46 B of the outer tube  44  so that withdrawal of the liquid  22  from the drum  24  via the outer tube  44  does not create suction that seals the outer tube  44  to a bottom of the drum  24 . The method preferably includes the step of providing a at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor  34 , the processor  34  is configured to automatically determine the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal. The module may be provided via dvd, on a processor, or via electronic download or the like. The method may provide the step of providing a processor  34  including the at least one software module thereon, wherein the processor  34  is configured to automatically determine at least the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal. The provided processor may be that already owned by a user of the invention. This would enable a first sensor to be properly positioned in the drum and have electronic signals transferred to a computer on which the requisite software module is downloaded without departing from the scope of the present invention. 
         [0072]    Referring to  FIG. 18 , a view of the graphic user interface (GUI)  200  of the processor  34  is shown. The GUI  200  may be located on the processor  34  or may be accessible online or by the use of an electronic device. The GUI  200  preferably has the name of the dairy farm  202 , or other business, at the top. Under the name  202 , the GUI  200  may have the current date  204  and the current time  206 . Below the date and time  204 ,  206 , the GUI  200  may have pictures of drums  208  showing the depth of the liquid  210  in the drum  208 . Underneath the pictures of the drums  208 , the GUI  200  preferably lists the type of liquid  212  in each drum, the volume of the liquid  214  in the drum, the pump status  216 , and the weeks until pump failure  222 . The GUI  200  may indicate that the pump has not reached its minimum volume threshold level for a wash by showing an “X”  220  next to pump status  216 . If the pump has met the minimum volume threshold, the GUI  200  may indicate the pump is okay by showing a checkmark  218  next to pump status  216 . To the left of the pictures of the drums  208 , the GUI  200  may have a contact dealer  224  button and a contact service provider button  226  that, when pressed, automatically contact the dealer and service provider, respectively, either by a call, text, email, or the like. The GUI  200  may also have a contacts button  228  that allows a user to view and contact all stored contacts. At the bottom of the GUI  200  may be a bunch of buttons such as buttons that may allow a user to view valve status  230 , view current alerts  236 , view wash history  230 , view alert and reply history  238 , maintenance log  240 , and a button to stop wash immediately  234 . However those of ordinary skill in the art will recognize that the GUI  200  may include any suitable data, information, artwork, phrases, numbers, words, letters, or the like, in any arrangement without departing from the scope of the invention. 
         [0073]    The method may include the step of configuring the processor  34  to receive a plurality of inputs representing at least one of a dimension of the drum  24 , a dimension of the sensor apparatus  20 , and a specific gravity of the liquid  22  for use in computing a volume of the liquid  22  in the drum  24 . The method may include the step of configuring the processor  34  to subtract the ambient pressure outside the drum  24  from the pressure of the liquid  22  at a bottom of the drum  24 . The method may include the step of configuring the processor  34  such that the plurality of inputs may be entered via a remote electronic device. The method may include the step of configuring the processor  34  to automatically determine the depth of the liquid  22  in the drum  24  according to: H=(P b −P a )/(PPIC*SG liquid ), wherein P b  is the pressure in the drum  24  at the opening  36  of the tube  26  as measured by the first sensor  32 A, P a  is the atmospheric pressure outside the drum  24  as measured by the second sensor  32 B, SG liquid  is the specific gravity of the liquid inside the drum  24 , H is the depth, or height, of the liquid inside the drum  24  and above the opening  36 , PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening  36 , and 249.17 is the standard pressure exerted by a one inch column of water. The method may include the step of configuring the processor  34  to automatically determining the volume of the liquid in the drum  24  and taking into account any adjustment needed due to the presence of the tube  26  therein by using the depth of the liquid in the drum  24  and dimensions of the drum  24  to determine an initial volume of liquid  22  in the drum  24 , then the processor  34  automatically adjusts the initial volume of liquid  22  in the drum  24  to get a final volume of liquid  22  in the drum  24  that takes into account the tube  26 , according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A), wherein H is the depth of liquid in the drum  24 ; Vdrum-final is the final volume of liquid in the drum  24 ; Vdrum-initial is the initial volume of liquid in the drum  24 ; A is a cross sectional area of the tube  26 ; Dliquid-in-sensor is the depth of the liquid in the tube  26  determined as follows: Dliquid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)), wherein L is a length of the tube  26 ; Pi is the initial pressure in the tube  26  prior to insertion of the tube  26  in the liquid; Vi is the initial volume of the tube  26  that is calculated by the dimensions of the tube  26 ; Ti is the initial temperature of air in the tube  26 ; Pf is a pressure in the tube  26  when the tube  26  is submerged in the liquid as calculated by the first sensor  32 A; and Tf is the final temperature of the air inside the tube  26  when the tube  26  is submerged. Those of ordinary skill in the art will recognize that the above formulas may be modified, or other formulas used in replace, without departing from the scope of the invention. The method may include the step of configuring the processor  34  to collect a plurality of usage data comprising at least one of a time, a temperature of liquid, and a volume of liquid withdrawn from the drum  24 . The method may include the step of configuring the processor  34  to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. Although the first and second sensors are preferably air pressure sensors, one ordinary skill in the art will appreciate from this disclosure that any other suitable sensor may be used without departing from the scope of the present invention. 
         [0074]    Referring to  FIGS. 11-13 , one method according to the present invention is directed to a method for measuring a depth of a liquid  22  in a drum  24  used as part of a system for use in at least one of agricultural, equipment cleaning, and animal husbandry. The method preferably includes providing the drum  24  configured to contain the liquid  22  used in the system. Preferably, the drum  24  is cylindrically shaped, however, the drum  24  may be of any shape or dimensions without departing from the scope of the invention. The method preferably includes providing a first sensor  32 A located in fluid communication with an inside of the drum  24 , the first sensor  32 A being an air pressure sensor generating a first signal corresponding to the pressure of the liquid  22  at a bottom of the drum  24 . Those of ordinary skill in the art will recognize that the first sensor  32 A may generate a first signal corresponding to the pressure of the liquid  22  at any predetermined or known distance from the bottom of the drum  24  without departing from the scope of the invention. The method preferable includes providing a second sensor  32 B in fluid communication with ambient atmosphere outside of the drum  24 , the second sensor  32 B being an air pressure sensor generating a second signal corresponding to ambient pressure outside the drum  24 . Those of ordinary skill in the art will appreciate from this disclosure that any type of sensor can or other suitable device can be used as the first or second sensor without departing from the scope of the present invention. Similarly, the second sensor can be omitted entirely without departing from the scope of the present invention. Alternatively, the second sensor  32 B may be in fluid communication with air inside the drum  24 . As previously discussed, the second sensor  32 B may be provided in order to obtain more accurate calculations of the depth of the liquid  22  in the drum  24  by accounting for changes in pressure due to changes the atmospheric pressure or by wind gusts, etc. As such, those of ordinary skill in the art will recognize that the method does not need to provide a second sensor or second signal. The method may include the step of providing a tube  26  having a first end and a second end  28 A,  28 B, wherein the second end  28 B may be configured for placement within the liquid  22 . The method may include an outer tube  44  having third and fourth ends  46 A,  46 B disposed over the tube  26 , wherein the outer tube  44  is configured to withdraw the liquid  22  from the drum  24  when the tube  26  is inserted into a hole  42  in a top  40  of the drum  24 . The method preferably includes the step of determining the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal. This step may further comprise of providing at least one software module stored on a non-transitory computer readable storage medium, the software module being configured such that when operating on a processor  34 , the processor  34  is configured to automatically determine the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal. The method may include the step of providing a processor  34  including the at least one software module thereon, wherein the processor  34  automatically determines the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal. This step may further include the processor  34  being configured to receive a plurality of inputs representing at least one of a dimension of the drum  24 , a dimension of the sensor apparatus  20 , and a specific gravity of the liquid  22  for use in computing a volume of the liquid  22  in the drum  24 . This step may further include the processor  34  being configured to subtract the ambient pressure outside the drum  24  from the pressure of the liquid  22  at a bottom of the drum  24 . This step may further include the processor  34  being configured for entry of the plurality of inputs via a remote electronic device. This step may further include the processor  34  being configured to automatically determine the depth of the liquid  22  in the drum  24  according to: H=(P b −P a )/(PPIC*SG liquid ), wherein P b  is the pressure in the drum  24  at the opening  36  of the tube  26  as measured by the first sensor  32 A, P a  is the atmospheric pressure outside the drum  24  as measured by the second sensor  32 B, SG liquid  is the specific gravity of the liquid inside the drum  24 , H is the depth, or height, of the liquid inside the drum  24  and above the opening  36 , PPIC is determined by ((H−TUBE liquidinches )* 249 . 17 )/H), where TUBE liquidinches  is the height of liquid in the tube above the opening  36 , and 249.17 is the standard pressure exerted by a one inch column of water. This step may further include the processor  34  automatically determining a volume of the liquid in the drum  24  and taking into account any adjustment needed due to the presence of the tube  26  therein by using the depth of the liquid in the drum  24  and dimensions of the drum  24  to determine an initial volume of liquid in the drum  24 , then the processor  34  automatically adjusts the initial volume of liquid in the drum  24  to get a final volume of liquid in the drum  24  that takes into account the tube  26 , according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A), wherein H is the depth of liquid in the drum; Vdrum-final is the final volume of liquid in the drum; Vdrum-initial is the initial volume of liquid in the drum  24 ; A is a cross sectional area of the tube  26 ; Dliquid-in-sensor is the depth of the liquid in the tube  26  determined as follows: Dliquid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)), wherein L is a length of the tube  26 ; Pi is the initial pressure in the tube  26  prior to insertion of the tube  26  in the liquid; Vi is the initial volume of the tube  26  that is calculated by the dimensions of the tube  26 ; Ti is the initial temperature of air in the tube  26 ; Pf is a pressure in the tube  26  when the tube  26  is submerged in the liquid as calculated by the first sensor  32 A; and Tf is the final temperature of the air inside the tube  26  when the tube  26  is submerged. This step may further include the processor  34  being configured to collect a plurality of usage data comprising at least one of a time, a temperature, and the volume of liquid  22  withdrawn from the drum  24 . This step may further include the processor  34  being configured to compare the plurality of usage data against a plurality of predetermined data and issue an alert when a discrepancy occurs. The step of providing the drum  24  may include the system being a dairy wash system that is configured to use the liquid  22  in the drum  24 . The dairy wash system may perform a predetermined number of washes, wherein the dairy wash system only withdraws liquid  22  from the drum  24  during a wash. The step of providing the processor  34  may also include the processor  34  being configured to determine when the wash is taking place and when the wash is completed by analyzing the first and second signals. The step of providing the processor  34  may further include the processor  34  being configured to determine a volume of liquid  22  used during the wash. The step of providing the processor  34  may further include the processor  34  being configured to send an alert if the volume of liquid  22  used during the wash is lower than a predetermined volume, or, if the volume of liquid  22  in the drum  24  is below a predetermined minimum volume. A person of ordinary skill in the art will recognize that a wash may use multiple liquids that are in multiple drums. As such, each liquid, or drum, may include the aforementioned method. A person of ordinary skill in the art will recognize that at least one processor  34  may be used to measure the depth of liquid and/or a volume of liquid  22  in each drum simultaneously. A person of ordinary skill in the art will further recognize that a wash may use multiple liquids at the same time, or at different times, and the processor  34  may be configured to determine whether a wash has occurred by analyzing at least one of: a change in depth of at least one liquid, a change in volume of at least one liquid, an order for which each of the liquids was withdrawn, a time of withdrawal of at least one liquid, a duration of withdrawal of at least one liquid, a temperature of at least one liquid, etc. 
         [0075]    Referring to  FIGS. 14-16 , one method according to the present invention is directed to a method for providing a system for measuring a depth of a liquid  22  in a drum  24 . The method preferably includes the step of providing a first sensor  32 A configured to be located in fluid communication with an inside of the drum  24 , wherein the first sensor  32 A may be an air pressure sensor that generates a first signal corresponding to the pressure of the liquid  22  at a bottom of the drum  24 . The method preferable includes the step of providing a second sensor  32 B configured to be in fluid communication with ambient atmosphere outside of the drum  24 , wherein the second sensor  32 B may be an air pressure sensor that generates a second signal corresponding to ambient pressure outside the drum  24 . The method may include the step of providing a tube  26  having a first end and a second end  28 A,  28 B, wherein the second end  28 B may be configured for placement within the liquid  22 . The step of providing the tube  26  may further include an outer tube  44  having third and fourth ends  46 A,  46 B and configured to be disposed over the tube  26 , wherein the outer tube  44  may be configured to withdraw the liquid  22  from the drum  24  when the system is inserted into a hole  42  in a top  40  of the drum  24 . The method preferably includes the step of providing at least one software module stored on a non-transitory computer readable storage medium. The software module may be configured such that when operating on a processor  34 , the processor  34  is configured to automatically determine the depth of the liquid  22  in the drum  24  based on at least one of the first signal and the second signal and to automatically determine whether a liquid  22  withdrawal has occurred or whether changes in the first signal represent a non-withdrawal event. A withdrawal event is when liquid from the drum is purposefully being withdrawn. A non withdrawal event can be any event that changes pressure in the drum, but is not actually a purposeful liquid withdrawal, such as a jostling of the drum, knocking of the sensor apparatus, a strong wind, sudden change in temperature from hail or other weather, or the like. 
         [0076]    The method may comprise the step of providing a processor  34  that includes the at least one software module thereon, wherein the processor  34  receives the first and second signals and automatically determines the depth of the liquid  22  in the drum  24  and automatically determines whether a liquid  22  withdrawal has occurred or whether changes in the first signal represent a non-withdrawal event. This step may further include the processor  34  being configured to receive a plurality of inputs representing at least one of a dimension of the drum  24 , a dimension of the sensor apparatus  20 , and a specific gravity of the liquid  22  for use in computing a volume of the liquid  22  in the drum  24 . This step may further include the processor  34  being configured to subtract the ambient pressure outside the drum  24  from the pressure of the liquid  22  at a bottom of the drum  24 . This step may further include the processor  34  being configured for entry of the plurality of inputs via a remote electronic device. This step may further include the processor  34  being configured to automatically determine the depth of the liquid  22  in the drum  24  according to: H=(P b −P a )/(PPIC*SG liquid ), wherein P b  is the pressure in the drum  24  at the opening  36  of the tube  26  as measured by the first sensor  32 A, P a  is the atmospheric pressure outside the drum  24  as measured by the second sensor  32 B, SG liquid  is the specific gravity of the liquid inside the drum  24 , H is the depth, or height, of the liquid inside the drum  24  and above the opening  36 , PPIC is determined by ((H−TUBE liquidinches )*249.17)/H), where TUBE liquidinches  is the height of liquid in the tube above the opening  36 , and 249.17 is the standard pressure exerted by a one inch column of water. This step may further include the processor  34  automatically determining a volume of the liquid  22  in the drum  24  and taking into account any adjustment needed due to the presence of the tube  26  therein by using the depth of the liquid  22  in the drum  24  and dimensions of the drum  24  to determine an initial volume of liquid  22  in the drum  24 , then the processor  34  automatically adjusts the initial volume of liquid  22  in the drum  24  to get a final volume of liquid  22  in the drum  24  that takes into account the tube  26 , according to: Vdrum-final=Vdrum-initial−((H-Dliquid-in-sensor)*A), wherein H is the depth of liquid  22  in the drum  24 ; Vdrum-final is the final volume of liquid  22  in the drum; Vdrum-initial is the initial volume of liquid  22  in the drum; A is a cross sectional area of the tube  26 ; Dliquid-in-sensor is the depth of the liquid in the tube  26  determined as follows: Dliquid-in-sensor=(L−(((Pi*Vi/Ti)*(Tf/Pf))/A)), wherein L is a length of the tube  26 ; Pi is the initial pressure in the tube  26  prior to insertion of the tube  26  in the liquid; Vi is the initial volume of the tube  26  that is calculated by the dimensions of the tube  26 ; Ti is the initial temperature of air in the tube  26 ; Pf is a pressure in the tube  26  when the tube  26  is submerged in the liquid  22  as calculated by the first sensor  32 A; and Tf is the final temperature of the air inside the tube  26  when the tube  26  is submerged. This step may further include the processor  34  being configured to collect a plurality of usage data comprising at least one of a time, a temperature, and the volume of liquid  22  withdrawn from the drum  24 . 
         [0077]    The step of determining whether the liquid  22  withdrawal has occurred may further include the first sensor  32 A generating the first signal at a predetermined interval and the second sensor  32 B generating the second signal at the predetermined interval. The step of providing the processor  34  may include the processor  34  being configured to store a plurality of readings, wherein the plurality of readings may be any one of the first signal and the first signal minus the second signal. Said another way, the plurality of readings may be any one of a pressure of the liquid  22  at a certain depth, or, a pressure of the liquid  22  at a certain depth minus the pressure of the air outside or inside the drum  24 . The step of providing the processor  34  may include the processor  34  being configured to compile a report, wherein the report may be an average of the plurality of readings over a predetermined time. For example, if the first and second sensors  32 A,  32 B generate first and second signals every second, and, a report was compiled by the processor  34  every minute, then, the report would be the average of sixty readings. The step of providing the processor  34  may further include the processor  34  being configured to store at least two of the reports. Preferably, the processor  34  stores the newest at least two reports compiled. More preferably, the processor  34  stores the newest at least three reports compiled. More preferably still, the processor  34  stores the newest at least five reports compiled. The step of providing the processor  34  may further include the processor  34  being configured to determine a pressure difference between at least two of the reports. The step of providing the processor  34  may further include the processor  34  being configured to recognize the liquid withdrawal when the pressure difference between at least two of the reports is greater than a predetermined pressure. The step of providing the processor  34  may further include the processor  34  being configured to determine a total pressure difference when the liquid withdrawal has ended between the pressure of the liquid  22  at the bottom of the drum  24  before the liquid withdrawal started and the pressure of the liquid  22  at the bottom of the drum  24  after the liquid withdrawal ended. The step of providing the processor  34  may further include the processor  34  being configured to determine a volume of the liquid withdrawn in the liquid withdrawal by analyzing the total pressure difference. 
         [0078]    A preferred method of determining whether a liquid withdrawal has occurred or whether changes in the first signal represent a non-withdrawal event operates as follows. The preferred method is not limiting, but is solely meant to provide an example. The liquid  22  in a drum  24  may be used for the purpose of washing dairy equipment. Preferably, the washing cycle for the dairy equipment withdrawals liquid  22  from the drum  24  for a predetermined amount of time. The first and second sensors  32 A,  32 B may generate first and second signals, respectively, every 512 milliseconds. Preferably, but not necessarily, the processor  34  stores a plurality of readings wherein each reading is the pressure at the bottom of the drum  24  as measured by the first sensor  32 A and carried in the first signal minus the pressure of ambient air outside the drum  24  as measured by the second sensor  32 B and carried in the second signal. Preferably, but not necessarily, the processor  34  compiles a report that averages a plurality of readings over a time period that is equal to or greater than the predetermined amount of time the washing cycle withdrawals liquid  22  from the drum  24 . More preferably, the processor  34  compiles a report that averages a plurality of readings over a time period that is equal to the predetermined amount of time the washing cycle withdrawals liquid  22  from the drum  24 . Preferably, but not required, the processor  34  stores the five newest reports compiled. For simplicity, assume that the reports are numbered 1-5 where 1 is the newest report compiled and 5 is the 5 th  newest report compiled such that as soon as a report is compiled it becomes number one and the other reports move down a number as follows: 1 becomes 2, 2 becomes 3, 3 becomes 4, 4 becomes 5, and 5 gets deleted. Since the length of time the washing cycle withdrawals liquid  22  is preferably equal to the length of time to generate a new report, a withdrawal by the washing cycle may only occur during a single report or two consecutive reports. Said another way, if a liquid withdrawal started at some point within the readings averaged by the third report, the liquid withdrawal would have ended at some point within the readings averaged by the second report. Preferably, the processor  34  compares the average pressures taken in the fifth report and the third report. Preferably, if the average pressure taken in the fifth report minus the average pressure taken in the third report is greater than twenty Pascal&#39;s, the processor  34  determines a withdrawal has taken place. Preferably, the processor  34  uses the average pressure taken in the first report as the post-withdrawal pressure at the bottom of the drum  24  after determining a liquid withdrawal has taken place. Preferably, the processor  34  determines the pressure drop caused by a liquid withdrawal by taking the fifth report minus the first report instantaneously after the processor  34  determines a withdrawal has occurred. The processor  34  may use the pressure drop to determine the depth of liquid  22  used in the liquid withdrawal and/or to determine the volume of liquid  22  used in the washing cycle. Preferably, if the volume of liquid  22  used in the washing cycle is lower than a predetermined volume, the processor  34  is configured to send an alert. Preferably, the alert re-sends after a predetermined amount of time in perpetuity until an acknowledgement, such as a text reply, is received by the processor. However, the acknowledgment may be any other suitable acknowledgment of the alert without departing from the scope of the invention. 
         [0079]    Referring to  FIGS. 1 ,  3 ,  4 ,  7 A, and  7 B, one embodiment of at least one sensor apparatus  20  for use in a dairy wash system operates as follows. Preferably, but not necessarily, the dairy wash system includes a washing cycle for dairy equipment. Preferably, the washing cycle commences after milking of cows. Preferably, the washing cycle withdrawals three different kinds of liquids that are located in separate drums. The liquids are preferably withdrawn by hoses  48  attached to pumps  54 . The hoses  48  may have a temperature sensor thereon to measure the temperature of liquid  22  flowing through the hose  48 . However, the washing cycle may withdrawal any number of liquids from any number of drums without departing from the scope of the invention. Preferably, the three liquids used are a detergent, an acid, and a sanitizer. Preferably, each of the liquids are in their own drum, wherein each drum  24  includes a sensor apparatus  20  therein. Preferably, the first and second sensors  32 A,  32 B in each sensor apparatus  20  are electronically connected to a single processor  34 . However, any number of processors may be used without departing from the scope of the invention. Preferably, the processor  34  is configured for entry of a plurality of inputs via a text from a cell phone. However, those of ordinary skill in the art will appreciate that the plurality of inputs may be entered via any electronic device. Preferably, the plurality of inputs the processor  34  is configured to receive is at least one of: number of liquids used in washing cycle, order in which the liquids are to be withdrawn from their respective drums during the washing cycle wherein at least two liquids may be programmed to be withdrawn at the same time, the specific gravities of the liquids used, the number of washing cycles expected per day, the number of seconds each pump  54  is configured to withdrawal each liquid  22  out of their respective drums, phone numbers to send a text message alert to, and the dairy name. 
         [0080]    Preferably, as seen in  FIGS. 7A and 7B , the processor  34  is further configured to determine when a washing cycle has begun and ended. Referring to  FIG. 7A , the processor  34  is preferably configured to determine when a washing cycle has started and ended by first determining if the temperature recorded by a temperature sensor on a milk line has risen a predetermined number of degrees in a predetermined time period  104 , therefore, meaning that the milking of cows is over. If the processor  34  has determined that the temperature of the milk line has risen a predetermined number of degrees within a predetermined time period  104 , the processor  34  is preferably configured to start storing readings  108  of the pressure measured by the first sensor  32 A minus the pressure measured by the second sensor  32 B for each of the sensor apparatus&#39;s. Preferably, the processor  34  is further configured to start compiling reports  118  for each sensor apparatus  20 , wherein, preferably, the length of time the processor  34  takes to compile a new report for any given sensor apparatus  20  is the same amount of time the liquid  22  the sensor apparatus  20  is placed in is programmed to be withdrawn from the drum  24  during a wash cycle. Preferably, the processor  34  is configured to store the newest of at least two reports for every liquid  22  used in the washing cycle. More preferably, the processor  34  is configured to store the newest of at least three reports for every liquid  22  used in the washing cycle. More preferably still, the processor  34  is configured to store the newest five reports for every liquid  22  used in the washing cycle. 
         [0081]    Still referring to  FIG. 7A , preferably, the processor  34  is further configured to analyze  120  the stored reports for each liquid  22 . Preferably, the processor  34  determines whether a liquid withdrawal has started  122  in any of the liquids used in the washing cycle. Specifically, the processor  34  preferably determines whether there is greater than a twenty Pascal pressure difference in the fifth newest report and first newest report and, whether there is less than a twenty Pascal pressure difference between the fifth newest report and the third newest report for all liquids used. If so, the processor  34  is preferably configured to determine that a withdrawal of the respective liquid has just started  124 . If not, the processor  34  preferably starts the determination again when a new report is compiled. Preferably, the processor  34  is configured to determine a wash cycle has begun  128  when the processor  34  determines that a withdrawal has started on any of the liquids. Preferably, the processor  34  records the time the processor  34  determines a washing cycle has started, and, the number of washing cycles performed each day  128 . 
         [0082]    After a liquid withdrawal has occurred for any of the liquids, the processor  34  preferably is configured to determine when the liquid withdrawal has ended  132  by determining whether the pressure difference between the fifth newest report and the third newest report is greater than twenty Pascal&#39;s. If so the processor  34  is configured to determine that the liquid withdrawal for that particular liquid has ended. After determining a liquid withdrawal for a particular liquid  22  has ended, the processor  34  is preferably configured to immediately determine the pressure drop  134  of the liquid  22  at the bottom of the drum  24  by subtracting the first newest report from the fifth newest report. Subsequently, the processor  34  is preferably configured to determine the order  138  that each liquid&#39;s withdrawal ended. After the processor  34  determines that a withdrawal has started on at least one liquid, the processor  34  may be configured to start a timer  130  such that if the processor  34  fails to determine that the liquid withdrawal has ended within a predetermined length of time, the processor  34  may reverse its determination that a withdrawal has taken place. 
         [0083]    After a liquid withdrawal for each liquid has ended, and, the order in which the liquids were withdrawn has been determined, the processor  34  is preferably configured to perform another check  142  to ensure a washing cycle, and liquid withdrawals, have indeed taken place. The check  142  preferably includes the processor  34  configured to determine if at least four of following have occurred: the processor  34  has determined a wash cycle has started; the order in which the processor  34  determined the liquid withdrawals occurred matches the order in which the liquids are to be withdrawn that was entered into the processor  34 ; if the pressure at the bottom of each drum  24  has dropped by thirty or more Pascal&#39;s; if the temperature recorded by a temperature sensor on the milk line has risen a predetermined number of degrees in a predetermined time period; and if the temperature sensors on each hose  48  are consistent with predetermined temperatures. If at least four have occurred  144 , the processor  34  is preferably configured to confirm the washing cycle  156 . Subsequently, the processor  34  is preferably configured to send an alert  160  if any data collected by the processor  34 , such as temperature of the liquids flowing through the hose  48 , the time of a washing cycle, or a pressure differential at the bottom of the drums after a liquid withdrawal has occurred, is inconsistent with a plurality of predetermined data. If less than four have occurred, the processor  34  preferably reverses its determination that the washing cycle has started  148 . Subsequently, the processor  34  preferably begins analyzing  120  the stored reports again.  FIGS. 8 ,  9 ,  10 A- 10 B,  11 ,  12 ,  13 A- 13 B,  14 ,  15 , and  16 A- 16 B illustrate alternative preferred methods for providing a system for measuring a depth of a liquid in a drum. 
         [0084]    Referring to  FIG. 22 , another preferred method of providing a sensor apparatus for measuring a depth of a liquid in a drum above an initial drum liquid height is provided. It is preferred that the drum include a sidewall. The method preferably includes the step of providing a tube having a first end and a second end. The second end may be disposed on the sidewall of the drum such that the tube and an inside of the drum are in fluid communication. The second end is preferably located on the sidewall proximate the initial drum liquid height. 
         [0085]    The method may include the step of providing a seal positioned in the tube and spaced from the second end. The method may also include the step of providing a first sensor disposed in the tube between the seal and the second end and configured to measure air pressure in the tube. The method may further include the step of providing a processor in electronic communication with the first sensor, wherein the processor automatically determines the depth of liquid in the tank not including the initial drum liquid height. 
         [0086]    Referring to  FIG. 23 , a sample GUI for a smart phone is shown. However, those of ordinary skill in the art will recognize that the smart phone can be a tablet, an internet website, or any other electronic device without departing from the scope of the invention. The name of the dairy farm  202  may be the contact name in the smart phone. In addition to the processor  34  being configured to send a text alert  256  if any data is inconsistent with a plurality of predetermined data, the processor  34 , as best seen in  FIG. 23 , is further preferably configured to send a text inquiry reply  254 , such as the volume of liquid remaining in a drum, when a text inquiry  252  is asked. However, those of ordinary skill in the art will recognize that the inquiries may be made by any other suitable way, such as voice communication or email, without departing from the scope of the invention. Similarly, inquiry replies by the processor need not be by text, but may be made in any other suitable way without departing from the scope of the invention. Supply companies that supply certain chemicals, detergent, or other liquids to dairy farms, or other industries, often find it hard to expand their business past a certain point due the hassle of having to stop at each dairy farm when on a run to fill up drums  24  of liquid  22 . Allowing the suppliers to ask the processor  34  the volume of liquids in drums on the dairy farms they supply may allow the suppliers to skip dairy farms when on a supply run if the dairy farm does not need their drums re-filled that day, thereby, allowing the suppliers to expand the number of customers they may have. 
         [0087]    It is common for pumps  54  to die or stop functioning after a certain amount of time or use. Usually before a pump  54  stops functioning, the pump gradually pumps lower and lower volumes of liquid during a specific time interval. Therefore, it may be advantageous to configure a processor  34  to determine and store the volume of liquid each pump pumps during a specific time interval and compare the results in order to predict when a pump  54  might fail, or, when the pump  54  may not withdrawal the predetermined minimum volume of liquid during a wash cycle. The processor  34  preferably is configured to store data comprising at least a volume of liquid pumped during each wash cycle. This data, and other data, may be stored on an SD slot card, or the like, and have a backup system such as a battery backup. The processor  34  is preferably further configured to compare the stored data of at least a volume of liquid pumped during each wash cycle in order to create a pump trend for each pump  54 . The processor  34  may be configured to send a text alert  256  if the volume of liquid pumped during a wash cycle is lower than a predetermined volume. Further, the processor is preferably configured to analyze the pump trend in order to determine how long it will take before the pump  54  fails or cannot meet the minimum volume threshold for a wash. 
         [0088]    While various shapes, configurations, and features have been described above and shown in the drawings for the various embodiments of the present invention, those of ordinary skill in the art will appreciate from this disclosure that any combination of the above features can be used without departing from the scope of the present invention. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover all modifications which are within the spirit and scope of the invention as defined by the appended claims and/or shown in the attached drawings.