Abstract:
A plumbing fixture includes a receptacle for receiving waste, a tank for storing water, and an electrically operated pump that conveys water from the tank into the receptacle to flush the waste through a drain. The duration that the pump in operated to flush the waste is altered in response to variation of the electrical voltage supplied to the plumbing fixture. The pump is operated to decrease the amount of water in the tank when that amount is sensed to be excessive. Further operation of the pump is inhibited for a given interval to avoid overheating when the pump has been operating too frequently. The pump is cycled on and off in predefined patterns to indicate different malfunctions to a user.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     The present invention relates to pump operated, water saving plumbing fixtures, such as toilets and urinals, and more particularly to controlling operation of the pump in such plumbing fixtures.  
         [0005]     2. Description of the Related Art  
         [0006]     Historically, toilets have a reservoir above the level of a toilet bowl so that, upon activation of the flush valve, water is fed by gravity from the reservoir into the toilet bowl. In the past typically three or more gallons of water was required for flushing the toilet. In recent years, the efficiency of such gravity fed toilets has been improved to the extent that in many cases 1.6 gallons of water is sufficient to remove waste from the bowl. However, where especially large amounts of feces are present, double flushing often was needed to remove the waste completely.  
         [0007]     A solution to the necessity to double flush a toilet while still using a reduced quantity of water is to pressurize the flush water entering the toilet bowl. U.S. Pat. No. 5,542,132 describes a toilet in which a pump draws water from a reservoir and feeds the water under pressure to the bowl. To achieve optimal water conservation the pump should supply just enough water to completely cleanse the bowl. However, manufacturing tolerances and altered alignment of parts can affect the water flow and thus adversely affect the flushing ability. Therefore a need exists to adjust operation of the pump for maximum efficiency with a given toilet.  
         [0008]     In addition, many pump style toilet have the reservoir located beneath the bowl for compactness as gravity flow no longer dictates the reservoir location. However, if this type of toilet becomes plugged, there is a possibility that an excessively high level of soiled water in the bowl may enter the rim outlets thereby contaminating the reservoir. At the completion of a flush, water in the conduit leading to the bowl rim flows back downward into the reservoir drawing air into the conduit. Upon the next flush that air is forced through the rim outlets, which produces an objectionable hissing sound, as well as delaying delivery of water into the bowl.  
         [0009]     Thus a need exists for an improved pump operated plumbing fixture.  
       SUMMARY OF THE INVENTION  
       [0010]     A plumbing fixture for receiving flushable waste comprises a receptacle for receiving the waste, a tank for storing a volume of water, and an electrically operated pump having an inlet in communication with the interior of the tank and having a pump outlet coupled to the receptacle. A sensor produces a level signal when the water in the tank reaches an abnormally high level. An input device is operable by a user to produce a flush signal. A controller is connected to the sensor, the input device and the pump. The controller responds to the level signal from the sensor by operating the pump to deliver water from the tank to the receptacle thereby preventing an excessive amount of water in the tank. In response to the flush signal, the controller operates the pump for a predefined interval to deliver water from the tank to the receptacle.  
         [0011]     In a preferred embodiment of the plumbing fixture, the predefined interval is altered in response to variation of electrical voltage supplied to power the toilet. Altering of the predefined interval, maintains pumping a relatively constant amount of water each time the waste is flushed from the receptacle.  
         [0012]     Another aspect of the present plumbing fixture involves inhibiting repeated operation of the pump in rapid succession which could result in the pump overheating or allowing the pump to be actuated with an insufficient quantity of water in the tank. Thus pump operation subsequent activation of the pump is inhibited for a given period of time. Preferably that given period is increased the more frequently that the pump operates.  
         [0013]     A further aspect of the present plumbing fixture utilizes an electrically operated valve in series with a convention flow valve which combined control the flow of water from a source into the tank. When the level sensor detects an abnormally large amount of water in the tank, the electrically operated valve is closed to prevent the tank from overflowing.  
         [0014]     In a preferred embodiment, the plumbing fixture cycles the pump on and off in various patterns to provide indications a different malfunctions to the user.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is an isometric view of a toilet that incorporates the present invention;  
         [0016]      FIG. 2  is a cross sectional view along line  2 - 2  in  FIG. 1 ;  
         [0017]      FIG. 3  is a detailed sectional view through a self priming check valve in  FIG. 2 ;  
         [0018]      FIG. 4  is a schematic diagram of the electrical circuitry of the toilet;  
         [0019]      FIGS. 5A and 5B  form a flowchart depicting the software program that is executed by a microcomputer in  FIG. 4 ; and  
         [0020]      FIG. 6  is a flowchart of a test routine that is called by the software program in  FIG. 5A . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Although the present invention is being described in the context controlling the operation of a toilet, the inventive concepts can be applied to other types of plumbing fixtures in which waste is removed by water forced from reservoir by a pump. For example, the present invention could be used with a urinal.  
         [0022]     With initial reference to  FIG. 1 , a toilet  10  includes a receptacle  12  in the form of a bowl with a hollow rim  14  having outlet openings extending downward into the bowl. A skirt  15  extends around and beneath the receptacle  12  providing an enclosure that houses a pump/tank assembly  16  that comprises an open top tank  17 , an inlet valve assembly  20 , and a flush pump  22 . The inlet valve assembly  20  controls the flow of water into the tank  17  from a supply pipe  18  of the plumbing system in a building. As will be described, the inlet valve assembly  20  includes an electrically operated valve and a conventional float valve connected in series to control the flow of water into the tank  17 .  
         [0023]     The sump-type flush pump  22  is located within the tank  17 . The flush pump  22  is driven by a motor with electric power being supplied by a connection  24  to the electrical wiring of the building in which the toilet is used. Any one of a variety of commerically available pumps may be used in the toilet  10 . Water enters the flush pump  22  via the inlets  26  and exits through an outlet pipe  28 . The pump outlet pipe  28  also is connected by a hose  34  to a backflow check valve  36  so as to provide a path to an inlet  38  under the receptacle  12 . Water that is delivered to the receptacle inlet  38  is directed by passages within the receptacle  12  to outlets around the underside of the rim  14  and to a jet channel at the bottom of the receptacle.  
         [0024]     The outlet pipe  28  has a side branch fitting to which a hose  30  is connected at one end and which has a self priming check valve  31  connected to the opposite end. Details of the priming check valve  31  are illustrated in  FIG. 3 . This valve comprises a tubular housing  32  that is secured in the hose  30  by a conventional hose clamp  37 . The housing contains a sphere  33  that selectively engages a valve seat  35  within the tubular housing  32 . With the flush pump turned off, the orientation of the priming check valve  31  enables the sphere  33  to drop away from the valve seat  35  which opens the valve and allows any air trapped in the flush pump to escape as water in the tank  17  enters the pump inlet  26 . Thus the flush pump  22  is self priming.  
         [0025]     The flush pump  22  and the water supply inlet valve assembly  20  are operated by an electronic controller  40  incorporated in the pump housing, the details of which are shown in  FIG. 4 . The electronic controller  40  includes a conventional microcomputer  42  which contains an internal memory and input/output circuits. The memory of the microcomputer  42  stores a software program which governs the operation of the toilet  10 . The microcomputer  42  receives an input signal from a water level sensor  44  mounted near the top of one side of the tank  17 , as shown in  FIG. 2 , to indicate when the water within the tank rises to an excessively high level which should not normally occur. A flush switch  46  provides an input device that is operated by the toilet user to send a signal to the microcomputer  42  when it is desired to flush the toilet  10 . A digital input port of the microcomputer  42  is connected to the output of an analog-to-digital converter (ADC)  48 , which receives the output voltage from the controller power supply  50  in order that the microcomputer  42  can sense the level of the supply voltage furnished to the toilet.  
         [0026]     The electronic controller  40  also includes a pump output circuit  52  which produces an electrical current for operating the flush pump  22  in response to an output signal from the microcomputer  42 . A valve output circuit  54  also receives a control signal from the microcomputer  42  and responds by operating an electrically controlled fill valve  56  within the inlet valve assembly  20  connected to the supply pipe  18 . A conventional float valve  58  is coupled in series with the fill valve  56  so that both valves must be in an open state in order for water from the supply pipe  18  to flow into the tank  17 . Under normal operation the conventional float valve  58  governs filling the tank with water and the water level never rises high enough to trigger the water level sensor  44 . Therefore, the electrically controlled fill valve  56  is a safeguard against the open top tank  17  overflowing.  
         [0027]     The electronic controller  40  is part of the pump/tank assembly  16  that includes the flush pump  22 , the tank  17  and their related plumbing fittings. The flush pump  22  and the controller  40  are tested and configured in the factory prior to assembly with the remaining components of the toilet  10 . For that purpose, the microcomputer  42  also is connected to a conventional universal asynchronous receiver/transmitter (UART)  60  which provides a bidirectional serial communication link via a serial port  62  of the controller. One pin of the serial port  62  is used to place the controller  40  in a test mode for configuring its operation.  
         [0028]     The configuration is carried out at a factory test stand that includes plumbing connections and a personal computer connected to an electronic scale on which a container is placed. The personal computer is connected to the serial port  62  of the electronic controller  40  and power is applied to the combination of the pump  22  and the controller  40 . Then the microcomputer  42  begins executing the stored software which is depicted in  FIG. 5A . At step  70 , the controller  40  is initialized by setting values of various constants and other parameters used during execution of the program. Next at step  72 , a determination is made whether a pin of the serial port  62  is pulled to ground by the connection of the cable from the test stand personal computer. As this connection is present during the factory configuration, the program execution branches from step  72  to step  74  at which the software calls a test routine represented by the flowchart in  FIG. 6 .  
         [0029]     The test routine commences at step  200  where a determination is made whether the flush switch  46  has been pressed. If not, the program execution continues to loop through that step. When the technician is ready to test the pump assembly operation, the flush switch  46  is depressed causing the program to advance to step  202 . At this juncture, the signal from the water level sensor  44  is inspected. As noted previously, this normally closed switch opens when an excessively high level of water is present in the tank  17 . If the switch is found to be open, or active, which state should not occur during the configuration process, the test routine terminates at step  204  after providing a message to the test stand computer that the pump/tank assembly  16  should be rejected.  
         [0030]     Assuming that the water level sensor  44  is functioning properly, the test routine advances to step  206  where a loop count variable within the memory of the microcomputer  42  is set to a value of one. The test routine then enters a loop where the flush interval for operating the flush pump  22  is determined. This process commences at step  208 , where the flush pump  22  is turned on for the flush interval which initially has a default value. The flush pump is activated by the microcomputer  42  sending a command signal to the pump output circuit  52  which in turn energizes the flush pump  22  for the prescribed interval which pumps water into container on the scales. After the flush pump has turned off, the container is weighed at step  210  to determine the weight of the water that was pumped from the tank. Next at step  212 , the weight of the pumped water is subtracted from the desired weight which corresponds to the optimum quantity of water that should be pumped during a flush operation. This arithmetic calculation produces the difference, designated Δ weight, between the desired weight and the pumped weight of the water. If the flush pump  22  pumped the optimum quantity of water, the value of Δ weight will be zero, however, in all likelihood an adjustment of the flush interval is required. Therefore, the flush interval is adjusted based on the value of Δ weight at step  214 . Specifically, a lookup table is used to convert the value of Δ weight to a time increment to be added to the present flush interval value to derive a new value for that interval. Specifically, if the value of Δ weight is positive, indicating that the pumped weight is less than the desired weight, the flush interval will be increased by adding a positive time increment. For negative values of Δ weight, as occur when the pumped weight is greater than the desired weight, the flush interval is decreased by adding a negative time increment. The newly calculated flush interval is stored within the memory of the microcomputer  43 .  
         [0031]     The test routine then advances to step  216  where the loop count is incremented by one and then tested at step  218  to determine if the new value is greater than three. The test routine makes three passes through the flush interval adjustment loop which should be sufficient, assuming that the components are operating properly, to accurately set the flush interval to a proper amount of water during each flush.  
         [0032]     At step  220  a determination is made at the completion of the flush interval adjustment loop whether the last value of Δ weight equals zero, as should occur if the flush interval has been properly set. If that statement is not true, the test routine terminates at step  220  where the pump/tank assembly  16  is rejected.  
         [0033]     Assuming that the configuration of the flush pump  22  passes the test at step  220  the test routine advances to step  224 . At this time, the controller  40  stores a reference value corresponding to the magnitude of the line voltage supplied to the toilet  10 . In the factory, a very accurate power source is used to furnish exactly 120 volts of alternating current to controllers  40  for North American use. For toilets that are to be used in European countries, a very accurate 240 volt power source is used. Therefore, at step  224 , the microcomputer  42  reads the input value from the analog-to-digital converter  48  that designates the voltage that is supplied to the controller  40 . This value corresponds to 120 or 240 volts and is stored at step  226  in the memory of the microcomputer  42  as the voltage reference value. The test routine then terminates by returning to step  76  of the main program depicted in  FIG. 5A .  
         [0034]     When a toilet  10  is installed in a building the control program bypasses the test routine and commences normal operation at step  76 . There the microcomputer  42  determines whether a water level sensor error flag has been set, which indicates that a faulty water level sensor  44  was found during previous operation of the controller. If this flag is found to be set, an attempt is made to rectify the problem by the program branching to step  78  where the flush pump  22  is pulsed on and off for a brief error interval. The program has several fault branches during which the flush pump  22  is pulsed different numbers of times to provide an indication of the nature of the fault to a plumber servicing the toilet. For this fault condition, the pump is activated five times for 0.5 seconds each with one second between each activation, for example (Pattern  1 ). In addition, operating the flush pump in this manner should pump enough water from the tank  17  into the receptacle  12  to lower the water below the water level sensor  44 , thus deactivating that switch. Therefore, after the flush pump  22  has shut off, the program execution waits for a brief period at step  80  to allow the switch to respond to the reduced water level. Then at step  82 , a determination is made whether the water level sensor  44  is still producing an active signal which will occur if the fault condition still exists. In that case, the program execution branches to step  84  where it waits forever. Once the program enters a wait forever state, the only way to reset the toilet operation is to disconnect and reconnect the electrical power. However, if at step  82 , the water level sensor  44  is found inactive, indicating that it responded to pumping water from the tank, the program execution advances to step  86  where the error flag is cleared. The program then returns to step  104  to commence normal operation of the toilet  10 .  
         [0035]     Returning for the moment to step  76 , if at this juncture the water level sensor error flag was not found set, the program branches to step  88  where a determination is made whether a high water level flag was set as may have occurred during the previous operation of the toilet. The high water level flag indicates that the tank  17  was filled to an usually high level, probably because the float valve  58  malfunctioned, but that the water level sensor  44  did function properly. If this flag is set, the program execution branches to step  90  where the flag is cleared before advancing to step  92  at which the flush pump  22  is pulsed on and off. For this fault condition, the pump is activated three times for 0.5 seconds each with one second between each activation, for example (Pattern  2 ). This pump activation provides a different pulse pattern that occurs at step  78  to indicate a fault due to a high water level error. Then at step  94 , the microcomputer  42  inspects the signal from the water level sensor  44 . If the water level sensor is not active, indicating the switch responded to the reduction of the water level produced by flush pump activation, the program execution transfers to step  104  to commence normal operation. Otherwise, if the water level sensor  44  is still producing an active signal, which at this time erroneously indicates an excessively high level of water in the tank, the program continues to step  96  where the flush pump  22  is activated twice again for 0.5 seconds with one second there between (Pattern  3 ). This action further reduces the amount of water in the tank  17  before entering a continuous wait state at step  98 . At this point, it has been determined that the water level sensor  44  is faulty and operation of the toilet is inhibited until corrective action is taken by the user. The controller remains in this wait state  98  until power is removed and the reapplied to the toilet  10 .  
         [0036]     If neither the switch error flag or the high water level flag is found set at steps  76  and  88 , the microcomputer  42  checks the signal from the water level sensor  44  at step  100 . If that switch is active the program branches to step  92 , otherwise the execution continues to step  104 .  
         [0037]     Assuming that the toilet  10  is operating properly, the control program eventually reaches step  104  in  FIG. 5A , at which the electrically operated tank fill valve  56  in  FIG. 4  is opened to fill the tank  17  with the proper amount of water. Note that the electrically operated fill valve  56  is in series with a conventional mechanical float valve  58  which responds to the level of water in the tank  17 . Thus, the controller  40  opens the fill valve  56  for predefined amount of time (e.g. 45 seconds) that normally is sufficient, even for relatively low water pressure within supply pipe  18 , to fill the tank  17  completely. Upon opening the fill valve  56 , the program advances to step  106  where the water level sensor  44  is monitored to ensure that the tank  17  does not overflow as it has an open top. Normally, the float valve  58  will shut off the flow of water into the tank before the level ever rises to the location of the water level sensor  44 .  
         [0038]     However, if that does not occur and the water level sensor  44  opens thereby producing an active signal, a transition occurs from step  106  to step  108 . This results in the microcomputer  42  closing the fill valve  56  immediately to shut off the flow of water into the tank  17 . The microcomputer  42  then sets the high water level flag at step  110 . Next at step  112 , the flush pump  22  is activated twice for 1.5 seconds with five seconds there between (Pattern  4 ) to reduce the water within the tank  17 . Then the signal from the water level sensor  44  is inspected again at step  114  to determine whether it is still active. An active signal at this point indicates that the switch may be faulty as the water level has been reduced below the location of that switch. In this case, the program execution advances to step  115  where the high water level flag is reset and the switch error flag is set at step  116  before entering a forever wait state  118 . However, if the pumping action deactivated the water level sensor  44  at step  114 , the program execution continuously loops through that step without setting the level sensor error flag, while still inhibiting further operation of the toilet until the cause of the abnormally high water level has been identified.  
         [0039]     Returning to step  106  from which the program advances to step  119  when the signal from the water level sensor  44  is not active, i.e. a normal water level exists in the tank  17 . Now the value of a refill timer implemented by the microcomputer  42  is checked to determine if it has timed-out, i.e. reached zero. If this timer has expired, the tank fill valve  56  is closed at step  120 , otherwise the program jumps around step  120  to step  122 . This results in the value of flush lockout timer being compared to the value of a variable designated pump lockout to prevent the toilet  10  from being flushed too frequently which could overheat the motor of the flush pump  22 . If the flush lockout timer has a value that is greater that the pump lockout value the toilet is inhibited from flushing the toilet again. In that case, the program returns to step  106  without checking the status of the flush switch  46  at step  124 . When the pump may be flushed again, the status of the flush switch  46  is checked at step  124  and if it is not being pressed, the program execution returns to step  106 . The program execution continues to loop through steps  106  and  119 - 124  until either the water level sensor  44  or the flush switch  46  is found to be active.  
         [0040]     When the signal from the flush switch  46  indicates that the user desires to flush the toilet, the program execution branches to step  126  on  FIG. 5B . At this time, the microcomputer  42  closes the tank fill valve  56 . The value of the flush lockout timer is checked at step  128  and if it is zero a counter is initialized to zero at step  130 . Regardless of the flush lockout timer value, the counter then is incremented by one at step  132 . The counter indicates the number of times that the flush pump is activated before the flush lockout timer expires. Each successive activation, increases the flush lockout timer and the counter value. Before that happens however, the pump lockout variable is set to the present value of the flush lockout timer at step  133 .  
         [0041]     The program execution enters a section that increases the flush lockout timer based on how frequently the pump  22  has been activated. At step  134  the microcomputer  42  determines whether the value of the counter equals one, as occurs the first time the toilet is flushed after expiration of the lockout timer. For that counter value, the program branches to step  136  at which the flush lockout timer is set to a relatively short interval, designated Flush 1 . The refill timer also is initialized to the predefined refill time and started. The program then decides at step  138 , whether the counter value equals two, as occurs after a subsequent flush operation, and if so an amount of time, designated Flush 2 , is added to the present value of the flush lockout timer at step  140 . The refill timer is initialized again. Another check of the counter value is made at step  142  and when a value of three is found, an additional amount of time (Flush 3 ) is added to the flush lockout timer at step  144 . More than three counter iterations and flush lockout timer adjustments may be provided. When a counter value in excess of three exists the program reaches step  146  at which the counter is decremented and more time (Flush 4 ) is added to the flush lockout timer. Each higher numbered additional flush time is greater than its predecessors to allow more motor cooling time with each successive flush. The flush pump  22  then is turned on at step  148 .  
         [0042]     At step  150 , the program measures the level of the A/C supply voltage by reading the output of the analog-to-digital converter (ADC)  48 . Preferably a plurality of measurements are taken over a period of time and averaged to provide a value representing the supply voltage. The speed at which the motor of the flush pump  22  operates is directly related to the magnitude of the supply voltage which is supplied to the toilet  10 . The flush period is set at the factory with the toilet being powered by exactly the nominal supply line voltage (120 or 240 volts) for the country in which it is intended to be used. However, the supply line voltage at a particular installation of the toilet  10  may deviate significantly from that nominal voltage level, thereby affecting the speed of the flush pump  22  and the amount of water that is pumped into the toilet receptacle  12 . For optimum water conservation, the amount of water used during each flush is maintained at the minimum level required to adequately remove waste from the toilet receptacle  12 . If the flush pump  22  operates too slow, an insufficient amount of water may be pumped to remove the waste. Similarly, if the flush pump operates to fast, a greater amount of water that is necessary is consumed. As a consequence, at step  150 , the supply voltage measurement is compared to the nominal voltage level that was stored in the microcomputer&#39;s memory during configuration at the factory. The difference between those voltage values is used at step  152  to access another look-up table within the memory of the microcomputer  42 . This action provides a time increment by which to adjust the flush period in order to compensate for the effects of the supply voltage deviation. That is, for an actual supply voltage that is less then the nominal level, resulting in less water being pumped for a given interval of time, the flush period is increased by the time increment from the look-up table. For voltages in excess of the nominal level that result in faster pump operation, the flush period is decreased by the obtained time increment. The adjustment time increment read from the look-up table is combined with the previous flush period value to produce a new flush period value that is stored within the memory of the microcomputer  42  for subsequent use.  
         [0043]     Then at step  154  the flush timer is continuously monitored and the flush pump is turned off at step  156  upon the timer expiring. Thereafter, at step  158  a determination is made whether the signal from the water level sensor  44  is active. If it is, the program jumps to step  108  to close the fill valve and take the remedial action at the subsequent steps described previously. Otherwise, the program progresses to step  160  to verify that the flush switch  46  is not stuck in the active, closed position. If that is the case, the program continues to loop through steps  158 - 160  until the problem is manually corrected. However, if the flush switch  46  is functioning properly, the program execution opens the tank fill valve at step  162  before looping back to step  106 . At some point thereafter, when the refill timer found to have elapsed at step  119 , the fill valve will be closed at step  120 . The normal operation of the toilet  10  continues to loop through steps  106 - 162 .  
         [0044]     The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.