Patent Abstract:
A dispenser control system for a washing machine having at least one electrically operated device includes a controller; at least one fluid transfer mechanism in communication with said controller and in fluid communication with said washing machine; a magnetic field sensor removably connected to an exterior housing of said electrically operated device, said connection made by a surface mount mechanical connector; and means for communicating a signal from said magnetic field sensor to said controller, said signal generated by said magnetic field sensor in response to detection by said sensor of a magnetic flux generated by said electrically operated device outside of said housing of said electrically operated device.

Full Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to commercial ware wash and laundry machines and, more particularly, to an improved sensor for dispensers used with these machines.  
       BACKGROUND OF THE INVENTION  
       [0002]     Accessory dispensing systems for commercial washing machines, such as ware wash and laundry machines, are frequently provided as accessory items by commercial cleaning chemical supply companies to help promote their cleaning products. As such, these systems are installed onto washing machines that are already in place and in use. The washing machines are typically self-contained units but require manual addition of the required chemicals, like rinse agent or detergent, for every load. The accessory dispensing systems provide for automatic dispensing of these chemicals from bulk storage reservoirs for less “hands-on” operation. These washing machines typically have at least one electrical motor or electrically controlled solenoid valve that operate various functions, e.g., wash, rinse, dry cycles, of the machine. These electrically operated devices are controlled by the washing machine and, therefore, do not require outside control.  
         [0003]     These accessory dispensing systems must directly or indirectly communicate with the washing machine in order to determine the appropriate time to transfer each particular required chemical to the washing machine. For example, the dispensing system must determine when a wash cycle is starting in order to trigger operation of the appropriate pump to transfer detergent to the machine. Similarly, the system must identify the beginning of a rinse cycle so that rinsing agent can be pumped into the washing machine at that time. The timing of the various cycles of these washing machines is typically indicated by the operation of specific motors or solenoid valves within the machine. Therefore, connecting the dispensing system to these specific motors and solenoid valves such that operation of these devices sends an electrical signal to the dispensing allows the system to determine the appropriate timing for transferring fluids.  
         [0004]     Currently, these dispensing systems are connected to the electrical components of washing machines through a hard-wired connection to each electrical component. This requires substantial dismantling of the washing machines to access the motors and solenoid valve electrical connections. These installation requirements introduce several significant drawbacks to these systems. First, because the interiors of the machine&#39;s motors and solenoid valve wiring are exposed, the danger of electrocution is present. Second, in part due to the preceding danger, it is necessary to involve a skilled electrician for installation. In some facilities, the requirement of utilizing an electrician can be prohibitive in terms of the resulting time and expense. Furthermore, in some systems it is difficult to locate the proper electrical contacts.  
         [0005]     The present invention is directed to overcoming one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0006]     An aspect of the present invention is to provide a means for controlling an accessory dispenser controller for commercial washing machines that eliminates the need for a hard-wired connection between the controller and the washing machine.  
         [0007]     Another aspect of the invention is to provide a means for controlling an accessory dispenser controller for a washing machine that may be installed without the assistance of an electrician.  
         [0008]     Yet another aspect of the invention is to provide an improved and safer method of installing a dispenser for a commercial washing machine.  
         [0009]     In accordance with the above aspects of the invention, there is provided a dispenser control system for a washing machine having at least one electrically operated device that includes a controller; at least one fluid transfer mechanism in communication with the controller and in fluid communication with the washing machine; a magnetic field sensor removably connected to an exterior housing of the electrically operated device, the connection being made by a non-invasive mechanical connector; and means for communicating a signal from the magnetic field sensor to the controller, the signal generated by the magnetic field sensor in response to detection by the sensor of a magnetic flux generated by the electrically operated device outside of the housing of the electrically operated device.  
         [0010]     In accordance with another aspect of the invention, there is provided a surface-mounted sensor for use with an accessory controller for electrically operated equipment that includes a surface mount mechanical connector; a housing adaptable for connection with said surface mount mechanical connector; a circuit board within said housing, said circuit board defining a flux field sensor; and means for communicating a signal from said circuit board to said accessory controller.  
         [0011]     These aspects are merely illustrative of the various aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Reference is now made to the drawings which illustrate the best known mode of carrying out the invention and wherein the same reference numerals indicate the same or similar parts throughout the several views.  
         [0013]      FIG. 1  is a block diagram of a dispenser control system according to an embodiment of the present invention.  
         [0014]      FIG. 2  is a perspective view of a dispenser control system according to another embodiment.  
         [0015]      FIG. 3  is a plan view of a magnetic field sensor according to another embodiment for use in a dispenser control system.  
         [0016]      FIG. 3A  is a section view of the magnetic field sensor taken along line A-A of  FIG. 3 .  
         [0017]      FIG. 4  is a plan view of a printed circuit board suitable for use in a magnetic field sensor according to another embodiment.  
         [0018]      FIG. 5  is a circuit diagram for the printed circuit board of  FIG. 4 .  
         [0019]      FIG. 6  is a block diagram of a dispenser control system incorporating a wirelessly operating magnetic field sensor. 
     
    
     DETAILED DESCRIPTION  
       [0020]     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.  
         [0021]     One embodiment of a magnetic field sensor  10  according to the present invention is illustrated in  FIGS. 3 and 3 A. The sensor  10  includes a housing  12 , alternately referred to as a potting box. The housing  12  contains and protects the electronic components of the sensor  10 , as well as providing a ready means for mounting the sensor where needed. In a preferred embodiment, the housing  12  is molded from a plastic material, such as polypropylene. The housing  12  is of a generally rectangular box shape, although the particular shape of the housing  12  is not central to the nature of the invention. The housing  12  is provided with one open end to allow for insertion of the sensor&#39;s electronic components. Depending on the manner in which the electronic components of the sensor  10  are mounted within the sensor  12 , the performance of the housing may be enhanced by orienting the housing  12  in a specific manner relative to the device being monitored. For example, if the electronic components are mounted to one side of the housing  12 , it is preferred to mount that side of the housing  12  against the exterior of the monitored device. This mounting preference may be clearly shown by a suitable alignment indicator  14  provided on the exterior surface of the housing  12 . In the illustrated embodiment, the alignment indicator  14  takes the form of writing on the exterior surface of the housing  12  intended to indicate that the opposite side of the housing  12  should be mounted against the exterior of the monitored device and, in particular, against the housing of the device&#39;s electrical coil in the case of a solenoid valve.  
         [0022]     In one embodiment, the electronic portion of the sensor  10  includes a printed circuit board  16  containing the circuitry comprising a Hall Effect sensor, an amplifier, and a filter. These elements are known to those in the art. A circuit diagram for the illustrated embodiment is shown in  FIG. 5 . The components utilized in the printed circuit board  16  of the illustrated embodiment are as shown in the following table:  
                                                                     No.   Quantity   Component   Description   Manufacturer                                1   3   C1, C2, C9   .01 uF 50 V X7R           2   3   C3, C5, C7   .1 uF 25 V X7R       3   2   C6, C10   10 uF 35 V       4   1   C8   .22 uF 16 V X7R       5   4   D1, D2, D3, D4   1N4148       6   1   D5   LED-Green   Lumex       7   3   OUT, V+, V−   Spring Socket   Amp       8   1   Q1   2N3904       9   3   R1, R4, R12   10 K 1/10 W 5%       10   1   R10   470 K 1/10 W 5%       11   1   R16   2.2 K 1/10 W 5%       12   6   R2, R5, R7,   4.7 K 1/10 W 5%               R8, R13, R15       13   2   R3, R9, R11   1 M 1/10 W 5%       14   2   R6, R14   100 K 1/10 W 5%       15   1   S1   SS495A2SP   Honeywell       16   1   U1   LM324D       17   1   PWB   Printed Wiring                   Panel                  
 
         [0023]     The printed circuit board  16  includes pin receptacles  18  to enable connection of the printed circuit board  16  to a cable assembly  20 . The cable assembly  20 , as shown in  FIG. 6 , advantageously includes three wires  22 ; one for power to the sensor, one return wire, and one for transmission of signals from the sensor. The wires  22  are preferably housed within a wiring jacket  24  for protection. At the controller end of the cable assembly  20 , a quick connector  26  is provided with terminals for each wire in the assembly. While it is not essential to the present invention, the quick connector  26  does allow for simple plug-in installation to the dispenser controller.  
         [0024]     During assembly of the sensor  10 , the printed circuit board  16  is inserted into the housing  12 . Wires  22  are inserted into the appropriate pin receptacle  18  on the printed circuit board  16 . The housing  12  is then filled completely with a potting compound  30 , such as a clear silicone, to further secure and protect the printed circuit board  16  and the connection between the PCB  16  and the cable assembly  20 .  
         [0025]      FIGS. 1 and 2  depict a dispenser system according to one embodiment incorporating a magnetic field sensor as previously described. The dispenser system includes a controller  32 , at least one fluid pump, valve, or other fluid transfer mechanism  34 , and at least one sensor  10 . The pump is operative for drawing fluid, such as rinse agent or detergent, from a reservoir  36 , and transferring the fluid via a supply line  38  to a washing machine  40 , such as a commercial ware wash or laundry machine. The fluid may be supplied into a specific fluid inlet of the washing machine or directly into the machine&#39;s washing tank.  
         [0026]     Dispensing systems as described herein are frequently provided as accessory items by commercial cleaning chemical supply companies to help promote their cleaning products. As such, these systems are installed onto washing machines that are already in place and in use. The washing machines are typically self-contained units but require manual addition of the required chemicals, like rinse agent or detergent, for proper cleaning. The accessory dispensing systems provide for automatic dispensing of these chemicals from bulk storage reservoirs for less “hands-on” operation. These washing machines typically have at least one electrical motor or electrically controlled solenoid valve that operate various functions, e.g., wash, rinse, dry cycles, of the machine. These electrically operated devices are controlled by the washing machine and, therefore, do not require outside control.  
         [0027]     Accessory dispensing systems as described herein must directly or indirectly communicate with the washing machine in order to determine the appropriate time to transfer each particular required chemical to the washing machine. For example, the dispensing system must determine when a wash cycle is starting in order to trigger operation of the appropriate pump to transfer detergent to the machine. Similarly, the system must identify the beginning of a rinse cycle so that rinsing agent can be pumped into the washing machine at that time. The timing of the various cycles of these washing machines is typically indicated by the operation of specific motors or solenoid valves within the machine. Therefore, connecting the dispensing system to these specific motors and solenoid valves such that operation of these devices sends an electrical signal to the dispensing allows the system to determine the appropriate timing for transferring fluids.  
         [0028]     Installation of the accessory dispensing systems described herein is accomplished by first mounting the dispenser controller  32  to a solid surface. Typically, the pump(s)  34  associated with the system are integrated with the controller  32 . A first fluid supply line  38  is installed between a pump  34  and a respective fluid reservoir  36 . A second supply line  38  is installed between each pump  34  and the washing machine  40 . Next, each sensor  10  is connected to the controller  32  by means of the cable assembly  20 . If a quick connector  26  is provided, the cable assembly  20  may simply plugged-in to a mating female connector on the controller  32 . One sensor  10  is used for each relevant electrically operated valve or motor  42  in the washing machine. A typical ware wash application will require two sensors. Laundry dispensers may require multiple sensors. Each sensor  10  is connected to the exterior housing of its associated electrically operated device. Advantageously, the sensor need not be hard-wired into the electrically operated device. Simply mounting the sensor  10  to the exterior housing of the device, in particular, adjacent the electrical coils of the solenoid or motor, suffices. In a preferred embodiment, the sensor  10  is strapped to the housing of the electrically operated device with a hook and loop fastener. However, many other surface mounting arrangements, for example releasable adhesives, are perfectly suitable.  
         [0029]     All of the controllable machine components on these washing machines operate on electromagnetic principles and, therefore, produce flux fields. Practical considerations of the design of these devices dictate that some portion of the flux field will leave the designed flux path. This stray flux will exist in a field surrounding the particular component. It will only be present when power is supplied to the solenoid or motor. The magnetic field sensor described herein detects stray flux fields around these electrically operated devices. It then converts this stray flux into an electrical signal that can be used to trigger operation of the dispenser. In the preferred embodiment, the sensor uses a Hall Effect sensor to sense the flux density in the vicinity of the sensor. The Hall Effect sensor produces an analog output proportional to the magnitude and polarity of the flux field surrounding it. This signal is then amplified and filtered to remove noise before it is transmitted to the controller.  
         [0030]     In another preferred embodiment, the sensor can be tuned to detect any specific flux fields. In one embodiment, the sensor is tuned to respond to fields surrounding alternating currents in the 50 Hz to 60 Hz range. The “tuning” of the sensor is a sensitivity adjustment. The flux density to which the sensor responds is adjusted. Generally speaking, the flux density decreases by the square of the distance from the source. Limiting the sensitivity allows sensors to be applied to closely positioned independent flux sources. This requires close magnetic coupling of the sensor to the flux source (putting the sensor in the right place on the coil). The ability to tune the sensor eliminates false signals due to spurious noise from transients in the subject machine. It also eliminates false triggers from permanent magnets that may be in the vicinity of the sensor. The sensitivity of the sensor can be advantageously limited so that the sensor does not respond to nearby electromechanical components. In another embodiment, the sensor incorporates a visual indicating LED that indicates when the sensor is activated by a flux field. This feature eases proper positioning of the sensor on the respective motor or solenoid during initial installation. When properly positioned, the sensor will reliably indicate the operation of the subject device and provide electrical isolation from it.  
         [0031]     While a wired version of the sensor has been previously described, the sensor may also be utilized in conjunction with wireless transmission of triggering signals to the dispenser controller. For example, radio frequency (RF) or infrared (IR) signals may be utilized. These transmission systems are well known in general, but have not been utilized in this capacity. In such a system, as illustrated in  FIG. 6 , the dispenser controller  44  is provided with a wireless signal receiver  46 . The connections between the controller  44  and the pump(s)  34 , reservoir  36 , and supply lines  38  remain the same. Rather than a wired cable assembly, the wireless magnetic field sensor  48  is provided with a wireless transmitter  50 . Because there is no electrical connection by which to supply the sensor  48  with power, the sensor  48  is also supplied with a power source  52 , such as a battery pack. The remainder of the sensor  48  is essentially the same as its wired counterpart. The sensor  48  and controller  44  operate in the same manner as the wired version.  
         [0032]     Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims and their equivalents.

Technology Classification (CPC): 3