Abstract:
An automated water testing apparatus and to a method of using the apparatus to test the amounts of dissolved salts and other solids in a water sample, where the apparatus includes a specially constructed sample bottle which preferably has a flexible wall and is fitted with a filter cap having a mesh top wall through which sample water can be poured to remove suspended matter, several beakers, a desiccator enclosure, a computer containing a database and an inventive computer program for executing method steps, and several devices in communication with and controlled by the computer and the program for executing the method, these devices preferably including a conductivity meter having a meter electrode, a robotic arm having a gripper, an analytical scale, a top loader balance scale and an oven.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of environmental monitoring. More specifically the present invention relates to an automated water testing apparatus and to a method of using the apparatus to test the amounts of dissolved salts and other solids in a water sample to meet the requirements of the Clean Water Act, found at 40 C.F.R. 136 and the Safe Drinking Water Act, found at 40 C.F.R. 141. The apparatus includes a specially constructed sample bottle which preferably has a flexible wall and is fitted with a screw-on removable filter cap having a mesh top wall through which sample water can be poured to remove suspended matter including organics and plant matter, at least one and preferably several receiving vessels preferably in the form of beakers, and a desiccator enclosure. The apparatus further includes a computer containing a database and an inventive computer program for executing most or all of the method, and several devices designed to be connected to the computer so that they are controlled by and relay data to the computer such as through a two-way bus. These devices preferably include a conductivity meter having a meter electrode, a robotic arm having a gripper, an analytical scale, a top loader balance scale and an oven. 
     The method, in summarized form, includes but is not limited to the steps of: providing the above apparatus; one of a person and the computer through operation of the robotic arm delivering a sample of water to be tested into the sample bottle and securing the filter cap onto the bottle; the computer operating the robotic arm to lift and place the conductivity meter electrode into the sample water and activating the conductivity meter to perform a test to determine the concentration of salt in the sample water; the computer operating the robotic arm gripper to grasp the bottle, to hold it over at least one and preferably sequentially over several receiving vessels such as a beakers, and to tilt the bottle to a sufficient angle from vertical and for a sufficient duration to pour a selected quantity of sample water through the filter cap and into each beaker; and the computer operating the gripper of the robotic arm to squeeze the plastic sample bottle at least one time to force water otherwise obstructed by suspended matter through the filter cap sequentially into each beaker; the computer operating the robotic arm to cause the gripper placing the beakers one at a time onto the scale; the scale automatically relaying to the database and recording the weight of each successive beaker and the water it contains, and the program subtracting the known tare weight of each beaker to determine the water sample weight within each beaker, until at least two successive weights of each given beaker match; placing the beakers into the oven between weighings; the computer operating the robotic arm to cause the robotic arm to place the beaker into the oven; the computer causing the oven to activate and heat the beakers to a first temperature for a first period of time until the water in the beakers is fully evaporated, leaving only solid residue from the sample water in each of the beakers, which may include a substantial quantity of salt; the computer operating the robotic arm to remove the beakers from the oven and to place them one at a time on the scale; the scale relaying the beaker and solids residue weight to the computer such that the weight data is stored in the database; the computer program calculating the ratio of solids to water by weight and displaying, storing and printing the ratio such as in milligrams per liter or in parts per million (ppm). The results of this total dissolved solids (TDS) test reveal whether the water sample meets EPA requirements of a maximum of 500 mg per liter for drinking water. 
     The squeeze force applied by the gripper to squeeze the sample bottle preferably is in a range of 1 to 7 pounds. Squeeze force at the higher end of this range is applied where there is a high concentration of suspended matter in the sample water, causing flow resistance through the filter cap mesh. The amount of squeezing is not determined by displacement. In pouring sample water into each beaker, the computer detects the weight of the beaker on the scale in real time, such that the computer knows when the given beaker has received the desired quantity of sample water whereupon the computer causes the robotic arm and gripper to stop pouring from the sample bottle. 
     Applicant has discovered that a suitable robotic arm that is produced by ST ROBOTICS™. Yet applicant found that the gripper provided with this robotic arm is not suitable for performing steps of the present invention, and therefore found it necessary to replace it with a different gripper made by another manufacturer, ROBOTIQ™ of Canada, for another purpose. The ROBOTIQ™ gripper is intended for gripping eggs. This gripper has an intuitively variable gripping and squeezing force and provides variable opening and closing speed. The grippers of other known robotic arms simply open and close with a fixed force and at a fixed speed. The several devices designed to be connected to the present computer can both read and write, incorporating a two-way bus. Each device sends data signals back to the computer and the computer sends signals to the device to control its operation. 
     Key inventive features include the squeezable sample bottle with the filter cap, the use of a robotic arm and gripper for tilting and squeezing the bottle, which is made possible by the use of the inventive bottle filter, preferably embodied in the filter cap, the synergy of the combination of these apparatus elements, the method steps, and the program itself which executes much of the inventive method. 
     2. Description of the Prior Art 
     There has long been water testing equipment and procedures for using the equipment. 
     Nakamura, et al, U.S. Pat. No. 5,306,087, issued on Apr. 26, 1994, discloses an apparatus for thermogravimetry. Nakamura, et al., provides a computer operated robotic arm which lifts sample containers on and off a thermobalance which weighs the containers empty and then full, and then subtracts the container weight. The steps performed, however, are not intended to meet and fall short of what is required for testing according to the above mentioned water quality Acts, such as conductivity testing to determine salt content and filtration to remove suspended solids and organics. 
     Razulis, U.S. Pat. No. 4,125,376, issued on Nov. 14, 1978, teaches a method for detecting water pollutants through the use of a sampling test tube containing a foam cube impregnated with a detection chemical solution. Once again, this method and apparatus fall far short of meeting the requirements of the Acts, as do the following prior patents. Tonge, et al., U.S. Patent Application Publication Number 2002/0092362, published on Jul. 17, 2002, reveals a flow-metering and sampling catch basin insert, providing means for isolating water entering a catch basin or manhole from flows from other catch basins so that the flow rate and water quality for water entering the catch basin can be measured without contamination. Las Navas Garcia, U.S. Pat. No. 7,172,729, issued on Feb. 6, 2007 discloses a mixed sample moisture or ash analyzer which uses a robotic arm to retrieve a crucible from a conveyor and to insert the crucible into a small opening in an upper wall of a furnace, placing it on a carousel inside the furnace. This patent does not address the requirements of water quality analysis. Finally, Pang, et al., U.S. Pat. No. 8,038,942, issued on Oct. 18, 2011, teaches an automated sample processing system involving the handling of biological specimen containers such as to perform centrifugation and decapping. 
     It is thus an object of the present invention to provide a water testing apparatus and method of using the apparatus which is largely or entirely automated to an extent that unattended operation is achieved and human operators are no longer necessary. 
     It is another object of the present invention to provide such a method which is largely or wholly executed by a computer and produces reliable results and meets government standards and requirements. 
     It is still another object of the present invention to provide such an apparatus includes an inventive sample bottle with a filter cap and makes new use of a robotic arm with a gripper, making such automation possible. 
     It is yet another object of the present invention to provide such an apparatus and method which employee use with only minimal training. 
     It is finally an object of the present invention to provide such an apparatus which provides greater precision with greater quality and which is safe and inexpensive enough to be practical. 
     SUMMARY OF THE INVENTION 
     The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification. 
     A water testing apparatus is provided, including a sample bottle fitted with a removable cap having cap rim and having a filter comprising filter mesh; at least one testing vessel; a desiccator enclosure; a computer containing a database and water testing computer program in operational communication the database; a computer operated robotic arm having a gripper in communication with the computer; a computer operated conductivity meter having a meter electrode and in communication with the computer; a computer operated scale for recording and storing weights in the computer database; and a computer operated oven in communication with the computer. 
     The filter mesh preferably is incorporated into the removable cap. The testing vessels preferably are beakers. The filter mesh is nominal, average size, preferably substantially 2 micron size. The at least one testing vessel preferably is a plurality of testing vessels. The testing vessels preferably are beakers. The at least one scale preferably is at least one of an analytical scale and a top loader balance scale. The sample bottle preferably is sized to contain 250 cubic centimeters. The sample bottle preferably is formed at least in part of polyethylene. 
     A method of testing water is provided to determine concentrations of dissolved solids, comprising the steps of: 
     providing the testing apparatus; one of a person and the computer operated robotic arm delivering a first water sample into the sample bottle and securing the filter cap onto the sample bottle; the robotic arm grasping the meter electrode and inserting the electrode into the water sample; the conductivity meter relaying sample water conductivity data to the database; the robotic arm sequentially placing the at least one of clean beakers into the oven; the computer signaling the oven to heat to a first temperature for a first length of time to thereby evaporate any moisture on or within the beakers; the robotic arm removing the beakers from the oven; the robotic arm placing the beakers sequentially into the desiccator enclosure; the robotic arm placing the beakers one at a time onto the analytical scale to transmit to the database and record the tare weight; the robotic arm placing each tared beaker on the scale one at a time; the robotic arm lifting the sample bottle and moving the sample bottle toward a first one of the beakers on the scale; the robotic arm moving the sample bottle to mix the water sample; inverting the sample bottle over the first one of the beakers; the robotic arm gripper then proportionately squeezing the sample bottle while the computer monitors the weight of the beaker and sample water as the sample water enters the first beaker; the gripper discontinuing the sample bottle squeezing once a desired volume of sample water is reached in the first beaker; the computer operating the robotic arm to sequentially repeat these beaker filling steps to fill a plurality of additional beakers; the computer operating the robotic arm to grip, lift and place the beakers into the oven; the computer operating the oven to increase its internal temperature to a second temperature for a second length of time to evaporate the water from the beakers, thereby heating the beakers and the residue within the beakers to the second temperature and permitting the beakers to remain heated at the second temperature until all of the water in the beakers has evaporated; and then heating the oven to a third temperature for a third length of time; the robotic arm removing the beakers from the oven; and placing the beakers into the desiccator enclosure to cool to the temperature of the balance itself; the robotic arm placing the beakers one at a time onto the scale; the scale transmitting the weights of each successive beaker and its corresponding contained residue to the database; the computer calculating the net weight of the residue in each beaker by subtracting the tare weight of the corresponding beaker; the computer calculating the quantity of total dissolved solids from the net weight and volume for each beaker; the computer repeating the weighings of each beaker to obtain constant weights according to stored criteria for each beaker; and, once the constant weight criteria is met for each beaker, the computer using the most recent weight to calculate the final total dissolved solids and storing and recording the final total dissolved solids for each beaker in the database. 
     The scale preferably is at least one of an analytical scale and a top loader balance scale. The volume of sample water for the test preferably (in milliliters) is substantially 25000/conductivity in micromhos. The first temperature preferably is substantially 105 degrees Celsius. The first length of time preferably is substantially two hours. The second temperature preferably is 98 degrees Celsius for the second length of time, which is however long is needed for the beakers to become completely dry, and normally is several hours. Then the oven temperature is raised to the third temperature of 180 degrees Celsius for the third length of time of one hour to drive off any occluded moisture. The calculation of total dissolved solids (TDS) from the net weight and volume taken preferably is made according to the formula: TDS (mg/1=(A−B)×1000/sample volume (in grams). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which: 
         FIG. 1  is a schematic view of the preferred water testing apparatus. 
         FIG. 2  is a perspective view of the preferred sample bottle with its inventive filter cap removed and of one of the several beakers preferably included with the apparatus. 
         FIG. 3  is a perspective view of the preferred robotic arm lifting one of the sample bottles from a rack of sample bottles to pour sample water into the beakers. 
         FIG. 4  is a perspective view of a preferred analytical balance scale, shown next to a rack of beakers. 
         FIG. 5  is a perspective view of a preferred top loader balance scale. 
         FIG. 6  is a block diagram of the preferred water testing method, most of which is a flow chart for the inventive computer program automating the method. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various FIGURES are designated by the same reference numerals. 
     First Preferred Embodiment 
     Referring to  FIG. 1-5 , a water testing apparatus  10  is disclosed including a computer  20  containing a database D and an inventive water testing computer program P in operational communication the database D and with a robotic arm  30  having a gripper  32 , a conductivity meter  40  having a meter electrode  40 A, an analytical scale  60  which records and stores multiple weights in the computer database, a top loader balance  70 , an oven  80 , and further including a water sample bottle  50  with threaded opening  50 A preferably sized to contain 250 cubic centimeters preferably formed of polyethylene and fitted with a removable filter cap  52  having an internally threaded cap rim  52 A and filter mesh  52 B across the top end of the cap rim  52 A; a plurality of testing vessels which preferably are beakers  54 ; and a desiccator enclosure  90 . The filter mesh  52 B preferably is nominal, average size, preferably 2 micron size. The plurality of beakers  54  preferably is a rack RK of beakers  54 . 
     The oven  90  door and desiccator enclosure  90  door each are preferably electro-gravity operated, and alternatively may be entirely electrically operated. For electro-gravity operation, the oven  80  and desiccator enclosure  90  are each mounted on four short legs. The legs on two diagonally opposed device corners can be electrically extendable and retractable to alternately cause forward and rearward device tilting. Extending the extendable rear leg while retracting the forward extendable leg tilts the device forwardly so that the device door can swing open and the robotic arm  30  can either place a beaker  54  or other item into or remove it from the interior of the device. Then retracting the extendable rear leg and extending the extendable front leg tilts the device backward, so that the device door can swing closed. A door stop structure is provided on each device to prevent the device door from opening to or beyond a fully perpendicularly position relative to the front of the device, so that tilting the device back will cause the door to swing closed rather than further open. The extension and retraction mechanisms of these legs can include a solenoid co-axial with the leg to drive the leg outwardly, or an electric motor rotating the leg which is externally threaded within a threaded leg passageway so that the leg advances outwardly or inwardly depending on the direction of its rotation by the motor, and is controlled by the computer  20  and the present program. This extendable leg arrangement has been found by applicant to be more practical than using the robotic arm  30  to pivot these doors. 
     Examples of either preferred or uniquely suited devices combined to create the present apparatus  10  are: the ST ROBOTICS™ robotic arm Model R17HP, the ROBOTIQ™ robotic gripper Model GC-001-ENIP, the HEWLETT PACKARD™ computer workstation Model xw 4600, SARTORIUS™ analytical balance Model MSA1245-100-DA, the SARTORIUS™ top loading balance Model MSA1202S-100-DO, VWR™ oven Model 414005-108 with electro-gravity operated door, and the AG conductivity meter Model 108. 
     Method 
     In practicing the invention, the following method may be used. See  FIG. 6 . The preferred method includes the steps of: providing the apparatus  10 ; a person or the robotic arm delivering sample water W into the sample bottle  50 ; the computer operating the robotic arm  30  to cause the robotic arm to grasp the meter electrode  40 A and inserting the meter electrode  40 A into the water sample W; the computer  20  operating the robotic arm to cause the robotic arm to sequentially place the at least one vessel and preferably a plurality of clean beakers  54  into the oven  80 ; the computer  20  signaling the oven  80  to heat to a first temperature for a first length of time to evaporate any moisture on or within the beakers  54 ; the computer  20  operating the robotic arm  30  to cause the robotic arm  30  to remove the beakers  54  from the oven  80  and to place the beakers  54  sequentially into the desiccator enclosure  90  for a length of time; the computer  20  operating the robotic arm  30  to cause the robotic arm  30  to place the beakers  54  one at a time onto the analytical scale  60  to record the tare weight and to store the tare weight of each beaker  54  in the database D; the robotic arm  30  placing each tared beaker  54  on the top loader balance  70  one at a time; computer  20  operating the robotic arm  30  to cause the robotic arm  30  to pick up the sample bottle  50  and move the sample bottle  50  toward a first one of the beakers  54  resting on the top loader balance  70 ; computer  20  operating the robotic arm  30  to cause the robotic arm  30  to rotate sample bottle  50 , preferably a partial rotation from vertical in opposing directions three times, to mix the water sample and inverting the sample bottle  50  over the first beaker  54 ; computer  20  operating the robotic arm  30  to cause the robotic arm gripper  32  to then proportionately squeeze the sample bottle  50  while the computer  20  monitors the weight of the water on the top loader balance scale  70  as the sample water W enters the first beaker  54  in real time; computer  20  operating the robotic arm  30  to cause the gripper  32  to terminate the squeezing of sample bottle  50  once a desired volume of sample water W is reached in the first beaker  54 ; the computer causing the robotic arm  30  to sequentially repeat these beaker  54  filling steps for each successive beaker  54  to fill a plurality of the beakers  54 ; the computer operating the robotic arm  30  to cause the robotic arm  30  to place each of the beakers  54  into the oven  80  to evaporate the water W from each beaker  54 ; the computer  20  operating the oven  80  to increase the oven  80  internal temperature to a second temperature for a second length of time, thereby heating the beakers  54  and residue R within the beakers  54  to the second temperature and permitting the beakers  54  to remain heated at the second temperature until all water is evaporated from the beakers  54 ; the computer operating the robotic arm  30  to remove the beakers  54  from the oven  80  and place the beakers  54  into the desiccator enclosure  90  to cool to the balance temperature; the computer operating the robotic arm  30  to place the beakers  54  one at a time onto the top loader balance scale  70 ; the computer  20  receiving weight transmitted by the top loader balance  70  of each successive beaker  54  and its corresponding contained residue R to the database D; the computer  20  subtracting the tare weight of each beaker  54  to calculate the net weight of the residue R in each beaker  54 ; the computer  20  calculating the total dissolved solids (TDS) from the net weight and volume for each beaker  54 ; the computer  20  repeating the weighings of each beaker  54  to obtain constant weights for each beaker  54  according to criteria stored in the database D; once the constant weight criteria is met for each beaker  54 , the computer  20  using the most recent weight to calculate the final TDS, and storing and recording the final TDS for each beaker  54  in the database D. 
     The volume needed for the test (in milliliters) is 25000/conductivity in micromhos. The first temperature preferably is substantially 105 degrees Celsius. The first length of time preferably is substantially two hours. The second temperature preferably is 98 degrees Celsius for a second length of time, which is however long is needed for the beakers to become completely dry, which normally is several hours. Then the temperature is raised to 180 degrees Celsius for a third length of time of one hour to drive off any occluded moisture. The calculation of total dissolved solids (TDS) from the net weight and volume taken preferably is made according to the formula: TDS ((mg/1=(A−B)×1000/sample volume (in grams)). 
     While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.