Patent Publication Number: US-6992590-B1

Title: Systems and methods for sensing a fluid supply status

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates generally to fluid supply systems and more particularly to systems and methods for sensing a fluid supply status in a fluid supply system. 
   2. Background 
   Soda fountains are commonplace in many fast food or convenience store locations. A soda fountain usually dispenses several different types of soda, or more generally several different carbonated beverages, from several different dispensers. When a customer activates a particular dispenser, the carbonated beverage is mixed as it is being dispensed. 
   A carbonated beverage dispensed by a soda fountain is a mixture of a syrup and carbonated water, the syrup being specific to the particular carbonated beverage. The syrup is usually contained in a bag. A pump pumps the syrup out of the bag and through a syrup supply line up to the dispenser. Water is also pumped up to the dispenser through a water supply line. Injecting Carbon Dioxide (CO 2 ) from a pressurized tank into the water supply line carbonates the water. 
   The pump that pumps the syrup is preferably a CO 2  pump and can, therefore, use CO 2  from the same tank that is used to carbonate the water. 
   The mixing process is mostly automated and is controlled by the amount of syrup and carbonated water pumped up to the dispenser as the beverage is being dispensed; however, there is presently no way to detect when the syrup bag or pressurized CO 2  are about to run out. Therefore, there is no way to prevent the soda fountain from dispensing beverages with no syrup when the syrup bag runs out. When the CO 2  runs, beverages will stop being dispensed altogether. This results in lost sales because the customer often decides not to purchase a beverage when they find that the soda fountain will not properly dispense their beverage of choice. Cumulative lost sales can be significant even if just a few sales are lost each time either the syrup or CO 2  runs out. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the systems and methods for sensing a fluid status, a system comprises a container containing a fluid, a fluid line coupled with the container, and a pump configured to pump the fluid out of the container through the fluid line. The system further includes a sensor comprising a wireless transmitter. The sensor is configured to sense the pressure in the fluid line and to periodically transmit, using the wireless transmitter, an alarm message when the pressure reaches an alarm threshold. 
   In one example embodiment, a control unit that comprises a wireless receiver receives the message. The control unit is configured to receive the alarm message, using the wireless receiver, and to output an alarm indication in response to the alarm message. 
   In another example embodiment, the control unit is configured to determine when the container is empty based at least in part on the status information. 
   In another example embodiment, the control unit is further configured to determine when the container is replaced or refilled based at least in part on the status information. 
   In another example embodiment, the control unit is also configured to determine how long it took to replace or refill the container. 
   In still another embodiment, the control unit includes a network interface communicatively coupled to a communication network, and a transmitter configured to transmit the status information and/or information related to the status information through the network interface. In this case, the system can also include a data processing center communicatively coupled to the communication network. The data processing center can then be configured to determine when the container is empty based at least in part on the status information and/or information related to the status information and/or determine when the container is replaced or refilled based at least in part on the status information and/or information related to the status information as well as how long it took to replace or refill the container. 

   
     Other aspects, advantages, and novel features of the invention will become apparent from the following Detailed Description of Preferred Embodiments, when considered in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the present inventions taught herein are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which: 
       FIG. 1  is a logical block diagram of an exemplary fluid delivery system; 
       FIG. 2  is a logical block diagram of an example fluid delivery system in accordance with the invention; 
       FIG. 3  is a logical block diagram of an example sensing device that can be used in the system of  FIG. 2 ; 
       FIG. 4  is a logical block diagram of an example control unit that can be used in the system of  FIG. 2 ; 
       FIG. 5  is a logical block diagram of another example fluid delivery system in accordance with the invention; 
       FIG. 6  is a logical block diagram of still another example fluid delivery system in accordance with the invention; and 
       FIG. 7  is a logical block diagram of still another example fluid delivery system in accordance with the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Although the following discussion relates generally to soda fountains, it will be apparent that the systems and methods for sensing a fluid supply status have far broader application within the scope of the claims that follow this description. Therefore, to the extent that the description refers to a soda fountain, or to any particular fluid supply system, this is by way of example only. Such references should not be seen to limit the scope of the invention in any way. 
     FIG. 1  is a logical block diagram of a system  100  that illustrates the functionality of a soda fountain. In system  100 , syrup, or some other fluid, is contained in container  102 . In this particular example, as in many soda fountains, container  102  comprises a bag  116 , which actually contains the syrup. The syrup is pumped from container  102  through fluid line  104  by pump  106 . Pump  106  pumps the syrup through line  104  up to dispenser  108 . More generally, dispenser  108  can be viewed as mixer of some sort. 
   There are many different types of pumps that are appropriate for use in fluid dispensing or fluid supply systems. The selection of a particular pump must be based on the requirements of the particular system. Pumps operate by changing the pressure the fluid line, e.g., line  104 , in a manner that causes the fluid, in this case syrup, to flow through the line. In system  100 , the syrup in container  102  is subject to ambient pressure, i.e., 14.7 psi. Therefore, pump  106  actually needs to reduce the pressure in line  104  in order to draw the syrup out of container  102  and up to dispenser  108 . 
   Flow control system  114  supplies water through water supply line  110  to dispenser  108 . Flow control system  114  can, depending on the implementation, comprise a pump, a valve or valves, or a combination thereof. As water flows through line  110 , carbonator  118  injects CO 2  from pressurized container or tank  112  into the water. 
   Unlike container  102 , pressurized tank  112  is under a very high pressure, e.g., 2000 psi or more. As pressurized tank  112  empties, the pressure in pressurized tank  112  drops until it reaches a point where no more CO 2  can be drawn or forced out of pressurized tank  112 . 
   As mentioned above, there is presently no efficient way to detect when bag  116  or pressurized container  112  are empty. This problem is not one which only affects soda fountains. Any system that supplies a fluid from a container or any system supplying a pressurized gas can be affected similarly. For example, pressurized CO 2  is also a key component of beer dispensing systems, e.g., in bars. In fact there are many different types of pressurized gas systems that use, for example, propane or some other gas besides CO 2 , in which it would be advantageous to be able to detect when the supply of pressurized gas has run out. 
   The systems and methods for sensing a fluid supply status address the problem by detecting the status of the fluids flowing in the system and reporting the status in a manner that can be used to generate alarm indications. The alarm indications allow for someone attending the system to correct the problem by refilling or replacing the fluid or pressurized gas supply. 
     FIG. 2  is a logical diagram of one example system  200  in accordance with the systems and methods for sensing a fluid supply status. As with system  100 , system  200  comprises a container  202  that contains a fluid such as syrup for a carbonated beverage. The fluid is pumped out of container  202  by pump  206 , which actually draws the fluid out by reducing the pressure in fluid line  204 . Additionally, flow control system  212  controls the flow of water through water supply line  210 . The water in water supply line  210  is carbonated by carbonator  222  using CO 2  from pressurized tank  214 . 
   As mentioned, the systems and methods for sensing a fluid supply status are not limited to soda fountains. Therefore, supply lines  204  and  210  are not limited to supplying carbonated beverage syrup and carbonated water. Moreover, there can be a plurality of fluid supply lines. For example, there will actually be a separate syrup container  202  and supply line  204  for each different type of beverage in a soda fountain. 
   In order to detect when container  202  or pressurized container  214  is empty, system  200  integrates sensing devices  208  and  216  respectively. Preferably, these sensors sense the pressure at appropriate points within system  200  and relay this information over wireless communication links  218  to a control unit  220 . Sensing devices  208  and  216  are unique with respect to each other and each must be select based on the requirements of the specific sensing application for which it is intended within system  200 . Additionally, it will be apparent that certain aspects of the systems and methods described herein apply separately to fluid supply lines, such as line  204 , and to supply lines that include in whole or in part pressurized gas, such as is the case with line  210 . As such, the sensors and their application will be discussed separately below starting with sensing device  208 . 
   As previously described, pump  206  supplies fluid from container  202  by reducing the pressure in line  204 . A pump, such as pump  206 , preferably cycles when in operation. Therefore, the pressure in line  204  actually oscillates up and down when fluid is being drawn out of container  202 . Thus, for example, in a soda fountain application, the pressure in line  204  preferably oscillates between approximately 14 psi and 12 psi when pump  206  is pumping fluid out of container  202 . 
   Pump  206  will continue to operate in this fashion until container  202  is empty. The coupling between container  202  and line  204  is preferably airtight; therefore, pump  206  will attempt to draw a vacuum, i.e., Øpsi, once container  202  is empty. This will result in a very sharp pressure drop in line  204 . 
   Sensing device  208  is coupled to line  204  and is designed to sense the pressure within line  204 . Sensing device  208  also includes a wireless transmitter for periodically transmitting messages related to the pressure in line  204  to a control unit  220 . As long as the pressure in line  204  is within a normal operating range, sensing device  208  preferably sends such messages infrequently, e.g., every 2 hours or so. If, however, a sharp pressure drop is detected, sensing device  208  preferably begins to transmit messages much more frequently. Control unit  220  can then generate an alarm indication for whoever is attending to system  200 . 
   It should be noted that sensing device  208  can be configured for a variety of pressure thresholds. In other words, sensing device  208  can generate an alarm when a variety of different pressure thresholds are reached with in line  204 , not just when a large pressure drop is detected. In this manner, the systems and methods for sensing a fluid supply status are adaptable to a variety of systems besides soda fountains. 
   The content of the message sent from sensing device  208  to control unit  220  can vary depending on the complexity of sensing device  208  and/or control unit  220 .  FIG. 3  illustrates a logical block diagram of an example sensing device  300 . Device  300  will be used to illustrate the varying complexity such a device can incorporate, and what effect the complexity can have on the information transmitted to control unit  220 . 
   Sensing device  300  includes a pressure sensor  302 . There are many different types of pressure sensors that can be incorporated into device  300 ; however the sensor must be selected in accordance with the requirements of a particular application. Therefore, the type of fluid container, type of fluid line, type of pump, type of fluid, accuracy required, etc., are all factors that can influence what type of pressure sensor is used. 
   Sensor  302  preferably translates pressure to an analog signal, which is input to Analog-to-Digital Converter (ADC)  304 . ADC  304  converts the analog signal to a digital output. 
   Sensing device  300  also includes a transmitter  310  for transmitting information over a communication channel, such as channel  218 . To control the operation of sensing device  300 , a processor of some type is preferably included within device  300 . Thus, in the simplest implementation, processor  306  can take the output of ADC  304  encode it appropriately and transmit it via transmitter  310 . In more advanced applications, processor  306  can process the output and then transmit different messages based on the result of such processing. Processor  306  can even, in certain implementations, store the information related to the pressure sensed by sensor  302  in a memory  308 . The stored information can then preferably be retreived later 
   Processor  306  can be any type of processor appropriate for the functionality required by sensing device  300 . Thus, processor  306  can be, for example, a microprocessor, microcontroller, Digital Signal Processor (DSP), or some combination thereof. Moreover, processor  306  may be included in an Application Specific Integrated Circuit (ASIC) that may also include ADC  304  and/or memory  308  as indicated by dashed line  312  in FIG.  3 . 
   Memory  304  is preferably included in sensing device  300  even if processor  306  does not store information in memory  308 . This is because memory  308  is needed to store the application code used by processor  306  to control the operation of sensing device  300 . Certain application code used by sensing device  300  will be discussed more fully below. 
   Therefore, processor  306  can simply transmit raw data relating to the pressure sensed by sensor  302 . Alternatively, processor  306  can process the raw data and select a message to transmit. For example, if processor  306  processes the raw data and determines that the pressure is within a normal operating range, then the processor can transmit a message indicating the flow status is normal. But if the processor processes the information and determines that the pressure has reached an alarm threshold, e.g. when a large pressure drop occurs in line  204 , then the processor can transmit an alarm message. 
   Depending on the amount of processing and memory resources included in sensing device  300 , processor  306  can transmit further information such as a time stamp, fluid line identifier, etc. 
   The complexity of the message transmitted will have a direct impact on the complexity of device  300  and, therefore, on the cost of device  300 . Thus, a tradeoff between complexity and cost is required. This tradeoff will also be impacted by the complexity and cost of the control unit.  FIG. 4  is a logical block diagram of an example control unit  400 , which can be used to illustrate the varying complexity that can be incorporated into such a unit. 
   Control unit  400  includes a receiver  402  configured to receive messages transmitted by a sensing device, such as sensing device  208 , via a communication channel, such as channel  218 . Processor  404  controls the operation of control unit  404  and receives the messages from receiver  402 . Memory  406  stores application code used by processor  404  and can also, depending on the implementation, store the messages received by receiver  402  or data related thereto. Alarm output  408  is used to generate an alarm whenever the messages received by receiver  402  indicate that an alarm condition exists in a fluid line such as fluid line  204 . 
   Control unit  400  can be a simple alarm unit or be much more complex. For example, if the messages received by receiver  402  are complex messages, e.g., the messages include a status, a fluid line identifier, etc., then unit  400  can be a simple alarm unit. In this case, processor  404  receives the message and outputs the appropriate alarm via alarm output  408 . 
   Alarm output  408  can comprise a variety of output devices. For example, Alarm output  408  can comprise a simple LED panel. When unit  400  receives an alarm message indicating a fluid container associated with a certain fluid line is empty, then processor  404  can cause a LED corresponding to that fluid line to be turned on. An attendant, upon seeing that the LED is turned on, would know to change or refill the bag associated with that line. Once the bag was replaced or refilled, then unit  400  will start receiving messages indicating that the pressure status in that line is normal and the LED will be turned off. 
   Alternatively, alarm output  408  can comprise a display such as an LCD display. In this case, when the messages received by receiver  402  indicate an alarm condition for a certain fluid line, processor  404  can cause an appropriate message to be displayed on the display. For example, processor  404  can display a message indicating the alarm condition and the fluid line identifier. The attendant can then change or refill the associated fluid container. Processor  404  would then stop displaying the message, or possibly, display a message indicating that the pressure has returned to normal in the particular fluid line. 
   The attendant may not be near control unit  400  when an alarm message is received. Therefore, it is preferable, that alarm output  408  comprises an audio output such as a buzzer. When an alarm message is received, processor  404  can then activate the audio output and alert an attendant even if the attendant is not near control unit  400 . An audio output can preferably be combined with a visual display, such as LEDs or an LCD. Further, If control unit  400  is a simple alarm unit, then it can even be portable so that it can be worn by the attendant. For example, control unit  400  could be a device similar to a pager. When there is an alarm condition the device can generate an audio output or vibrate and at the same time display a message indicating the fluid line that is the subject of the alarm. 
   If control unit  400  is a simple alarm unit, then it may or may not store information related to the messages received by receiver  402  in memory  406 . The more messages that need to be stored, the more memory is required and the more expensive the unit becomes. Therefore, the amount of memory must be traded off against he cost of the unit. If the messages are stored in memory  406 , then preferably they can be retrieved at a later time. 
   On the other hand, Control unit  400  can be much more complex. For example, if the messages received by receiver  402  only comprise raw sensor data, then processor  404  is required to process the data and determine what action to take. Processor  404  can even be configured to track the status of each fluid line in the system and to store the status in memory  406  for later retrieval. Moreover, processor  404  can be configured to store information related to the messages, such as the time of the message, the associated fluid line identifier, etc. From this information, processor  404  can be configured to determine related information, such as how long it took the attendant to replace or refill the container. This type of related information can be very valuable to the store operator, because it can be used to identify areas that need improvement, or more attention, in relation to a particular fluid delivery system. 
   Control unit  400  can even be part off a larger sensor network. For example, a convenience store location may include sensors sensing fluid lines in one or more soda fountains as well as sensors for sensing temperatures in refrigeration compartments and/or other types of sensors, with all of the sensors wirelessly reporting data back to control unit  400 . 
   Further, in certain implementations there may be more than one control unit. For example,  FIG. 5  is a logical block diagram of a system  500  that comprises two control units  514  and  516  in communication with sensing devices  502 ,  504 , and  506 , which monitor fluid lines  508 ,  510 , and  512  respectively. Preferably, control unit  514  is a simple alarm unit as described above and, therefore, may be stationary or portable. Control unit  516 , on the other hand, is preferably much more complex and is configured to store and track the status messages transmitted by sensing devices  502 ,  504 , and  506 . 
   Therefore, in one implementation, sensing devices  502 ,  504 , and  506 , transmit status messages to both control units  514  and  516 . The messages, therefore, must have enough information to allow control unit  514  to generate the appropriate alarm identifying the appropriate fluid line. The more information included in the messages, however, the more complex, and more expensive, sensing devices  502 ,  504 , and  506  become. 
   If less complex sensing devices are required, then system  500  can be configured such that sensing devices  502 ,  504 , and  506  only transmit to control unit  516 . Control unit  516  processes the messages and determines what action to take. Control unit  506  can then transmit a more complex message to control unit  514  containing the requisite information to allow control unit  514  to generate the appropriate alarm indication. This type of implementation of course requires that control unit  516  include a full wireless transceiver as opposed to just a receiver as described above. 
   The wireless communication channels  218  in  FIG. 2  are part of a wireless Local Area Network (LAN) included in system  200 . There are several wireless LAN protocols that define the encoding and channel access protocols to be used by devices, such as sensing device  208  and control unit  220 , when communicating with each other. For example, some common wireless LAN protocols are IEEE802.11, HomeRF™, and Bluetooth™, to name a few. Alternatively, a customized protocol can be defined that is specific to the particular implementation. The advantage of a customized protocol is that the overhead associated with the protocol can be reduced by only including functionality required for the particular system. This can be important since the application code that allows processor  306  and  404 , for example, to implement the protocol must be stored in memory, such as memories  308  and  406 . Thus, a reduced overhead protocol can be advantageous. 
     FIG. 6  is a logical block diagram illustrating a system  600  in which control unit  614  includes a network interface  618  allowing control unit  614  to communicate with a remote data processing center  620  via a communication network  616 . Preferably, network interface  618  is a wired connection to a Wide Area Network (WAN) or a Local Area Network (LAN). Although, network connection  618  can be, for example, a wireless interface to a wireless WAN  616 . Data processing center  620  is wired or wirelessly connected to network  616  through network interface  622 . 
   Data process center  620  can be configured to retrieve information related to the status of fluid lines  608 ,  610 , and/or  612  that is stored in control unit  614  or in sensing devices  602 ,  604 , and/or  612 . Alternatively, the information can be forwarded directly to data processing center  620  without first being stored. Data processing center can then be responsible for tracking and storing the status information and can be configured to determine related information, such as how long it took the attendant to replace or refill the container, as described above. 
   In certain implementations, control unit  614  can be configured to immediately forward messages received from sensing devices  602 ,  604 , and  606  to data processing center  620 . Data processing center  620  can then be configured to determine what action to take in response to the messages and instruct control unit  614  accordingly. For example, if an alarm condition exists, data processing center  620  can instruct control unit  614  to output an alarm indication. If a simple alarm unit is also included in system  600  as described above, then data processing center  620  can instruct control unit  614  to instruct the alarm unit to generate the alarm indication. 
   The discussion to this point has focused on fluid lines such as fluid line  204  in FIG.  2 . As noted, however, there can also be pressurized gas containers, such as container  214  that need to be monitored to ensure they do not run out. In the systems and methods for sensing a fluid supply status, sensing devices, such as device  216 , can be included to monitor the pressure in container  214 . In a soda fountain, there is typically one pressurized gas container; however, there are many systems that include pressurized gas supplies to which the systems and methods about to be described will apply. 
   Sensing device  216  monitors the pressure in container  214  and periodically transmits messages to control unit  220  in much the same manner as described above. Sensing device  216  can be very similar to device  300  described in relation to  FIG. 3 , but the sensor  302  used for device  216  will be unique relative to the sensor use for sensing device  208 , for example. Sensor  302  used in conjunction with a sensing device for pressurized gas containers, such as device  214 , must be selected according to the particular application. Thus, the type of container, the pressure the container is under, the type of gas, etc., are all factors that must be considered when selecting sensor  302  for use in a device, such as device  216 . 
   Unlike the pressure in line  204 , which oscillates within a normal operation range and then drops when container  202  is empty, the pressure in container  214  steadily drops as beverages are dispensed and CO 2  is consumed. Thus, sensing device  214  can periodically transmit messages with information related to the pressure in container  214 . As described above, this information can comprise simple raw data, or more complex information, such as a container identifier, pressure reading, etc. Control unit  220  receive the messages and predicts when container  214  will run out of gas. Based on this prediction, control unit  220  preferably generates an alarm indication to an attendant prior to the container running out. 
   In a soda fountain, the pressure in container  214  will not drop linearly, but will be influenced by the rate at which beverages are dispensed. In this case, the prediction made by unit  220  must be constantly updated and preferably takes into account patterns of consumption. When a system, such as system  200 , is first installed, however, control unit  220  will not have any data relating to rates of consumption for the system. In this case, control unit  220  preferably uses data from other similar locations/systems as an initial calibration from which to generate, in conjunction with the messages form device  216 , predictions of when container  214  will run out. This calibration data can then preferably be adaptively updated as data relating to system  200  is generated. 
   As described above, control unit  220  can include an alarm output for generating the alarm indication or it can be interfaced to a fixed or portable alarm unit, the sole function of which is preferably to generate the alarm indication. Additionally, the prediction, as well as any storage or tracking of data that is required, can be handled by a remote data processing center to which control unit  220  is interfaced via a network interface as described above. 
   It should also be noted that the systems and methods for sensing a fluid status are not necessarily restricted to sensing the pressure of pressurized gas containers. The systems and methods described herein are equally adaptable to containers or fluid supply systems involving pressurized liquids or other types of substances such as powders or foams. 
   It should be noted that including a wireless transmitter in a sensing device, such as device  208  or  216  in  FIG. 2 , can increase the cost and complexity of the sensing devices beyond an acceptable point.  FIG. 7  is a logical block diagram of an example system  700  that is designed to combat this problem. System  700  includes sensing devices  702 ,  704 , and  706 , which are coupled to, and configured to sense the pressure in, fluid lines  708 ,  710 , and  712  respectively. In this regard, sensing devices  702 ,  704 , and  706  are similar to sensing device  208 . But as will be apparent the systems and methods about to be described are equally applicable to systems that include sensing devices configured to sense the pressure in pressurized containers, such as container  214 . 
   Sensing devices  702 ,  704 , and  706  do not include wireless transmitters. Instead, they are coupled to a wireless transmit unit  714  via a LAN or other wired network  712 . Wireless communication unit  714  takes messages generated by devices  702 ,  704 , or  706 , encodes them in accordance with the protocol used for wireless communication within system  700  and transmits the messages to control unit  716  over wireless communication channel  718 . In this manner, the systems and methods for sensing a fluid supply status as described above can be adapted to systems that require less expensive sensing devices. 
   While embodiments and implementations of the invention have been shown and described, it should be apparent that many more embodiments and implementations are within the scope of the invention. Accordingly, the invention is not to be restricted, except in light of the claims and their equivalents.