Patent Publication Number: US-2006000849-A1

Title: Metering system having a portable controller

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims the benefit of priority to U.S. provisional patent application Ser. No. 60/563,668, filed on Apr. 20, 2004. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates to metering pumps, and the systems that control metering pumps.  
     BACKGROUND OF THE INVENTION  
      Metering pumps are used to accurately dispense a substance. For example, in industrial processes, a metering pump may be used to add a small amount of chemical to a large amount of liquid so the chemical has a desired effect on the industrial process. Further, since the cost of the chemical may be high, a metering system may be used to prevent over-use of the chemical.  
      There are many types of industrial processes which use metering pumps. Each industrial process may have requirements for a metering pump that are unique to that process, or that are common only to some of the many types of industrial processes. Consequently, suppliers of metering pump systems have many types of metering systems to accommodate the many types of industrial processes. As a result, metering system suppliers must manufacture and/or store a large number of different metering systems, have sales representatives who are knowledgeable about the large number of different metering systems, and have an engineering staff capable of designing and recommending proper servicing techniques for the large number of metering systems. As a result, the cost of a metering system is higher than if the number of types of metering systems was fewer.  
      Some metering systems include a metering pump and an onboard computer (a “pump-computer”), which may be attached to the pump base. The pump-computer is programmed to control the metering pump so that a desired amount of a substance is provided via the pump to a process. A personal digital assistant (“PDA”) may be used to provide a user interface with the pump-computer. The PDA may be used to download information from the pump-computer to the PDA. The PDA may also be used to upload information from the PDA to the pump-computer, for example, to alter the manner in which the pump-computer controls the metering pump.  
      The prior art systems allow the pump-computer to be reprogrammed via the PDA so as to change how the pump-computer controls the metering pump. In these systems, the PDA serves merely as a user interface. As such, programming changes to the pump-computer must be made at the pump-computer location.  
     SUMMARY OF THE INVENTION  
      The present invention may be embodied as a metering system. Such a metering system may have (1) a portable controller, (2) a metering pump in communication with the portable controller and capable of receiving signals from the portable controller, and (3) at least one process sensor in communication with the portable controller and capable of sending information signals to the portable controller. The portable controller may have one or more of the following: (1) a microprocessor, (2) a monitor, (3) memory, and (4) software for enabling the microprocessor to execute desired activities. The portable controller may be a PDA, capable of being held in a person&#39;s hand.  
      The present invention may be embodied as a method of dispensing a substance to a process. In such a method, (1) a portable controller may be provided, (2) a metering pump may be provided in communication with the portable controller, (3) a process sensor may be provided that is capable of sensing an aspect of the process, and is in communication with the portable controller, (4) process information may be communicated from the process sensor to the portable controller, (5) control information may be communicated from the portable controller to the metering pump, and (6) the substance may be dispensed from the pump to the process. The portable controller may be programmed at a remote location and shipped to the metering pump location for use in the metering system.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      For a fuller understanding of the nature and objects of the invention, reference should be made to the accompanying drawings and the subsequent description. Briefly, the drawings are:  
       FIG. 1 , which is a schematic representation of a system according to the invention.  
       FIG. 2 , which depicts a portable controller and a housing according to the invention.  
       FIG. 3 , which is a flow chart depicting a method according to the invention. 
    
    
     FURTHER DESCRIPTION OF THE INVENTION  
       FIG. 1  depicts an example of a metering system  10  according to the invention. In  FIG. 1 , there is shown a portable controller  13  having a microprocessor  16 . The portable controller  13  may be programmed to receive signals and send signals. In one embodiment of the invention, the portable controller  13  is a PDA, such as a Dell Axim™, available from Dell Inc. of Austin, Tex. The portability afforded by the portable controller  13  allows the portable controller  13  to be removed from the metering system  10  and sent to a central facility for reprogramming and/or repair. When one portable controller  13  is sent for reprogramming, a second portable controller  13  may be connected to the metering system  10 , so that the metering system  10  will operate while the first portable controller  13  is reprogrammed and/or repaired.  
      The portable controller  13  may have one or more memories  19  for storing information. For example, memories  19  may be provided to store one or more of the following: (1) process operational parameters, such as acceptable high and low conductivity levels, (2) process performance information, such as conductivity of a process at particular times, (3) information about control signals sent from the portable controller  13  to a metering pump  22 , which may be used to determine whether the portable controller  13  is reacting properly to process performance information based on the process operational parameters.  
      The portable controller  13  may have a built-in monitor  25 . The monitor  25  may be capable of displaying the process operational parameters, process performance information, and/or the information about control signals sent from the portable controller  13  to the metering pump  22 . The monitor  25  may be used to reprogram the portable controller  13  by providing a graphical user interface that allows a person to select desired operational parameters for the metering system  10 .  
       FIG. 2  depicts a portable controller  13  and a cradle  28  in which the portable controller  13  may be placed. The cradle  28  may provide electric power to the portable controller  13 , and may provide jacks where signals may be received from a process sensor  31  and/or signals may be sent to the metering pump  22 .  
       FIG. 2  also depicts a portion of the metering system  10  which includes a housing  34 . The portable controller  13  may be received in the housing  34 . The housing  34  may protect the portable controller  13  from an operating environment. For example, the housing  34  may protect the portable controller  13  from dirt, chemicals or radiant energy that might adversely impact the portable controller  13 . The housing  34  may include a hinged door  37 , which allows easy access to the portable controller  13 . The door  37  may have a translucent portion  38  through which the portable controller  13  may be viewed.  
      Referring to  FIG. 1 , the metering system  10  may include the metering pump  22  that is in communication with the portable controller  13  and capable of receiving signals from the portable controller  13 . The signals from the portable controller  13  to the metering pump  22  may be carried via a wired or wireless communication channel  23 . The metering pump  22  may be able to effect a change in an aspect of a process. For example, the metering pump  22  may be able to add a chemical to the process. One such application of a metering pump  22  might be to add a corrosion inhibitor to a crude oil distillate in order to protect a heat exchanger from corrosive properties of the distillate.  
      The metering system  10  may include at least one process sensor  31  in communication with the portable controller  13 . The process sensor  31  may be capable of sending information signals to the portable controller  13 , the information signals being related to an aspect of the process. For example, the process sensor  31  might measure the conductivity of a liquid, and send the information signal to the portable controller  13  in order to inform the portable controller  13  about the conductivity of the liquid. The portable controller  13  would then use the conductivity information to determine whether a metering pump should inject a chemical into the liquid in order to alter the conductivity of the liquid. The process sensor  31  may provide digital or analog information to the portable controller  13 . The process sensor  31  may include a flash memory to allow software changes, upgrades and fixes to be easily implemented.  
      More than one process sensor  31  may be bundled into a multi-sensor device. In this fashion, a metering system manufacturer may supply a single device that includes all the sensors normally used by, a particular type of facility. For example, to satisfy the needs of a cooling tower facility, a conductivity sensor, oxidation-reduction potential sensor, pH sensor and a temperature sensor may be placed in a single housing, and wires from each of the sensors may extend through a single sheath to the portable controller  13 . Since most metering systems deployed to service a cooling tower require these sensors  31 , bundling these sensors  31  into the multi-sensor device may make supplying and installing the metering system  10  easier and cheaper. The wires extending from the bundled sensors  31  and/or fittings attached to the wires may be color coded to indicate which sensor  31  is associated with a particular wire. Further, the multi-sensor housing may be color coded so one multi-sensor device may be easily distinguished from another multi-sensor device.  
      The process sensor  31  may be capable of sending an identification signal to the portable controller  13  identifying the process sensor  31  as being a particular type of process sensor  31 . In such a system, when the process sensor  31  is added to the metering system  10 , the process sensor  31  may send the identification signal to allow the portable controller  13  to know what type of process information will be provided and the form in which that information will be provided. For example, the process sensor  31  may provide a code that can be matched to a table of codes stored in a memory  19  of the portable controller  13 . Once a match is found in the table, the portable controller  13  may be able to access information necessary to interpret the information signal from process sensor  31 . In this manner, the portable controller  13  will be able to receive the information signal from the process sensor  31  and utilize the information to provide a corresponding signal to the metering pump  22 , and thereby effect a change to the process.  
      The process sensor  31  may include a sensor-transmitter  40  and the portable controller  13  may include a controller-receiver  43 . Communicating the information signals from the sensor-transmitter  40  to the controller-receiver  43  may be accomplished via a wireless or wired communication system, which may include the sensor-transmitter  40 , the controller-receiver  43  and one or more communication channels  44 . The controller-receiver  43  may be part of the cradle  28  in which the portable controller  13  resides. The information signals may be sent via a standard or proprietary communication protocol. For example, the information signals may be sent via a universal serial bus. Further, the information signals may be encrypted to prevent others from discovering the information being carried by the information signal.  
      The metering system  10  may include a communications hub  46  via which at least two process sensors  31  may communicate with the portable controller  13 . The communications hub  46  may include electronics to boost a signal from a process sensor  31  and/or multiplex signals from two or more process sensors  31 .  
      The portable controller  13  may include a memory  19  in which software may be stored. The software may be used to program the microprocessor  16  to execute desired activities. The microprocessor  16  may be programmed in an object oriented manner. The microprocessor  16  may execute a main program which periodically “passes” operational parameters to one or more code modules, and receives from the code modules one or more results. For example, the main program may retrieve from the memory the process operational parameters, such as water temperature threshold and water conductivity threshold. These operational parameters might then be “passed” to a first code module. The first code module might then determine a time when the metering pump  22  should dispense a chemical. The first code module may pass the determined time back to the main program, which then passes the current time and the determined time to a second code module. The second code module may then perform a comparison on the current time and the determined time to decide whether the determined time has been reached. If the determined time has been reached, the second module may set a flag such that upon a next check of the flag, the main program causes the microprocessor  16  to send a control signal to the metering pump  22 . Upon receiving the pump signal, the metering pump  22  would then dispense a quantity of water treatment chemical. In a similar manner, the program might also include one or more code modules to determine a quantity of chemical to be dispensed using operation parameters and information signals.  
       FIG. 3  depicts a method according to the invention. In the method, a substance, such as a chemical, may be dispensed to the process. A portable controller may be programmed  100 , for example, at a location distant from the process, according to specifications provided by an engineer. The programmed portable-controller may then be provided  103  to a facility where the process is located. For example, the programmed portable controller may be mailed to the facility.  
      A metering pump may be provided  106  in communication with the portable controller. To accomplish this, the metering pump may be provided in communication with a cradle, and the portable controller may be placed in the cradle so as to allow the portable controller to be in communication with the metering pump. A process sensor, which is capable of sensing an aspect of the process, may be provided  109  in communication with the portable controller, for example, via the cradle. Process information may be communicated  112  from the process sensor to the portable controller, and a corresponding control signal may be communicated  115  from the portable controller to the metering pump. The parameters of the control signal may be determined by the controller using software designed for analyzing the process information and selecting an appropriate corresponding control signal. The control signal may cause the metering pump to dispense  118  the substance.  
      The method may be carried out by storing operational parameters of the process in the portable controller, and the portable controller may use these to determine whether the substance should be dispensed to the process.  
      The method may be carried out to store process information provided by the process sensor. The process information may be stored in the portable controller. The portable controller may be removed from the metering system and delivered to an engineer for use in determining whether the substance delivered by the metering pump is having a desired effect on the process. The engineer may be located remotely from the metering system. When the portable controller is removed, a substitute portable controller may be used with the metering system.  
      When two portable controllers are used, one being the substitute portable controller, the metering system may be easily and cheaply installed. Complex communication systems are not required, and the portable controllers can be easily reprogrammed at a central facility, which may be far away from the metering system, thereby reducing costs normally associated with metering systems.  
      U.S. Patent Application No. 60/563,668 includes descriptions of other embodiments according to the invention. U.S. Patent Application No. 60/563,668 is hereby incorporated into this patent application by this reference.  
      Although the present invention has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present invention may be made without departing from the spirit and scope of the present invention. Hence, the present invention is deemed limited only by the appended claims and the reasonable interpretation thereof.