Abstract:
A microcontroller establishes normal operation and vacuuming operation profiles of time and vacuum for a pool or spa circulating pump. A user slightly adjusts the levels of vacuum within a predetermined range for storing a vacuum profile envelope within the memory for a normal pump circulating operation and a vacuum profile envelope within the memory for a vacuuming operation. A comparator compares actual inputs of time-from-start and pump vacuum with the normal operation envelope during normal operation of the circulating pump. The comparator compares real time inputs of the sensed vacuum and the time-from-start when the controller is in the vacuuming mode with the vacuuming envelope stored in the memory. Deviations of the sensed pressures from the envelope cause pump shutdown and alarm activation. A calibration switch is positioned inside a locked weatherproof control enclosure. That switch must be pressed before a pump start switch is started for normal circulating operations, or a vacuum switch is pushed for a pool or spa vacuuming operation. During or after the automatic calibration, variations of expanding or shrinking a deviation envelope may be controlled by switches before the calibration switch is deactivated. Lights blink with sequences to indicate selected vacuum levels, and the levels are displayed on an alphanumeric display. An auto restart switch is also located inside the locked control enclosure for allowing the system to automatically close the power relay and restart the pump after power outages.

Description:
BACKGROUND OF THE INVENTION 
     This application claims the benefit of U.S. Provisional Application No. 60/081,384, filed Apr. 10, 1998. 
    
    
     SUMMARY OF THE INVENTION 
     A Stingl-Switch is designed to give years of safe operation of a swimming pool, hot tub or spa. The Stingl-Switch is designed to prevent only body entrapment. To prevent disembowelment accidents, one must have properly installed and secured drain covers. Inspect the drain covers for cracks, fatigue, ultraviolet light or chemical degradation on a daily basis. Drain covers are inexpensive and if a problem is even suspected, replace the grate using only the manufacturer&#39;s supplied cover and stainless steel screws. Although there is no physiological data currently available as to how rapidly a disembowelment occurs, it is believed that the Stingl-Switch would lessen the physical damage inflicted. To prevent hair entrapment, use factory supplied anti-vortex drain covers. Anti-vortex drain covers are effective only at specific flow rates. Ensure that the flow rate is not exceeded. Contact the builder and the manufacturer of anti-vortex drain covers for specifics. 
     A preferred pool or spa circulating pump shut-off assembly has a water-circulating pump. A pump relay is connected to a power source. Pump power lines are connected to the pump relay and the pump for operating the pump. A sensor is connected to the pump for sensing change in fluid pressure in the pump. A processor is connected to the sensor for receiving signals from the sensor and for storing signals from the sensor during calibration. A comparator is connected to the processor for comparing real time signals from the sensor with stored calibration signals. The pump relay is connected to the processor for changing the relay and shutting off the pump assembly in response to substantial differences between real time signals and stored signals. 
     A preferred pump control switch apparatus for a pool or spa has a pump motor relay. A control is connected to the pump motor relay and a processor is connected to the control. A memory is connected to the processor. A vacuum sensor has an input connected to a suction side of a pump and an output connected to the processor. A timer is connected to the processor. A start switch is connected to the pump relay to start the pump. A calibration switch is connected to the processor for starting a calibration sequence wherein the processor records in the memory inputs from the timer and vacuum sensor during normal operation of the pump. A comparator is connected to the processor for comparing real time inputs to the processor from the timer and from the sensor with recorded inputs from the timer and sensor during calibration. An alarm relay is connected to the processor. The processor is connected to the pump relay and the alarm relay for opening the pump relay to turn off the pump and closing the alarm relay to turn on the alarm. 
     A preferred pool or spa water circulating pump control apparatus has a water-holding body, a water inlet and a water outlet connected to the body of water. A water return pipe is connected to the outlet. A suction pipe is connected to the inlet. A filter is connected to one of the pipes. A circulating pump has a suction side connected to the suction pipe and has a discharge side connected to the return pipe. A pressure sensor is connected to the suction pipe or to the suction side of the pump for sensing pressure therein. 
     A normally open pump relay has first and second power terminals. Electric power lines are connected to the first terminals of the pump relay. Pump power lines are connected to the pump and to second terminals of the pump relay. A transformer has a low voltage output and a high voltage input connected to the power lines. An alarm relay has energizing terminals. First and second power terminals are connected to the transformer and to the alarm. A direct current power supply is connected to the transformer. 
     A microcontroller is connected to the power supply, to the pressure sensor, to the pump relay and to the alarm relay, and a timer is connected to the microcontroller. 
     Under a calibration condition, the microcontroller reprograms a memory during normal circulating pump operation and then during vacuum cleaning operation of the circulating pump. The memory stores sensed pressure and time-from-start related variations of sensed pressure. An on-off switch is connected to the microprocessor for turning the microprocessor off or on. A start switch is connected to the microcontroller for starting the microcontroller in pump circulating condition for energizing the pump relay to operate the pump. An auto start switch is connected to the pump for automatically restarting the pump and controller when the power lines are activated by a timer control circuit. A vacuum cleaning switch is connected to the microcontroller for setting the microcontroller in vacuum cleaning condition and for energizing the pump relay to operate the pump. A calibration switch is connected to the microcontroller for reprogramming the memory. A comparator in the microcontroller compares present pressure and time-from-start with a profile of times and pressures stored in the memory. Out of scale differences actuate the microcontroller for energizing the alarm relay and deenergizing the pump relay, respectively turning on the alarm and turning off the pump. 
     These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a typical vacuum profile for a pump system in normal operation. 
     FIG. 2 is a vacuum profile of the Stingl-Switch in maintenance bypass mode. 
     FIG. 3 is a perspective view of the pump control box. 
     FIG. 4 is a perspective view of the internals of the pump control box. 
     FIGS. 5 and 6 are a schematic diagrams of the logic board and the high voltage board. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Each pump system (comprised of a pump, pipes, fittings, drain, etc.) has a unique vacuum profile. The Stingl-Switch works by monitoring vacuum on the influent side of a pool or spa pump and by comparing the vacuum against the known (calibrated) profile for the system. Any deviation from that calibrated profile indicates a possible trouble situation with the pump system, for which the Stingl-Switch can then take appropriate action. 
     FIG. 1 shows the basic shape of such a vacuum profile, which compares pump influent vacuum  3  with time  5 . 
     When power is first applied to the pump motor, several things happen before the pump system reaches steady-state “normal” operation. The mechanical inertia of the motor must be overcome as it comes up to operating RPM. The water standing in the pipes must be accelerated from a stationary state to the standard flow rate of the system. Depending on the location of the pump in relation to the pool, air may need to be primed out of the lines before water begins to flow. These “start up factors” result in a vacuum reading at the influent side of the pump starting at zero inches of mercury (0″ Hg) at power on 7, quickly rising 9 to a maximum value (Vprime) 11, then finally leveling off to some “normal” value. The amount of time required for the system to go from a stand still to normal flow is called Tstart  13 . 
     Once the pump system has primed, the pump system will reach a “steady state” vacuum called Vnormal  15 . Because normal operation of the system can cause minor fluctuations  16  in vacuum, and activity near the drain can cause small, harmless increases in vacuum, a “false alarm margin” of Vnormal+  17  is provided. Vnormal−  19  provides a margin against small drops in vacuum that may be caused by power fluctuations, as well as a “failsafe” in case the vacuum sense line to the Stingl-Switch is damaged or tampered with. 
     When a blockage occurs  21 , the moving column of water in the system will suddenly stop, causing a sharp spike  23  in vacuum. As the system vacuum exceeds Vnormal+  17 , the Stingl-Switch turns off the pump. The vacuum in the system will drop  25  to zero  27  very quickly. There is no need to “relieve” residual vacuum in the line because water is not compressible. The response time depends on the length of the drain lines, but it will usually be well less than 1 second. The blockage event will also cause internal and external audio and visual alarms to activate, indicating to the operator and maintenance personnel that a potential entrapment has occurred. The system must be restarted manually after the blockage is removed, preventing accidental restart during a rescue operation. 
     Because all pump systems are different in physical layout, the parameters of Tstart  13  and Vnormal  15  are different for each system. The values for the specific installation are automatically determined by the Stingl-Switch during the calibration mode, which, for safety reasons, may be activated only from inside the locked control box. In addition, the operator may want some flexibility in Vnormal+ and Vnormal− to determine the “sensitivity” of the system. A small margin about Vnormal causes more false alarms. However, the Stingl-Switch has pre-programmed limits so that the operator cannot unintentionally disable the effectiveness of the system by making the margin too large. 
     Most swimming pool and spa pump systems are used for operations other than normal filtration. In almost all cases (except very small spas), the pump system may also be connected to a vacuum wand to vacuum the pool. In that condition, the use of the vacuum wand may often cause spikes in the vacuum level similar to an entrapment, which would normally cause the Stingl-Switch to prematurely shut down the system. Because of this, the Stingl-Switch also has a Maintenance Bypass Mode. Instead of just disabling the safety feature of the switch, however, the system switches to the alternate maintenance vacuum profile  30 , as shown in FIG.  2 . 
     The profile is similar in shape to FIG. 1, which shows the normal operation vacuum profile  10 . However, in most pool systems the use of the vacuum wand is also accompanied by changing the position of several of the influent valves in the system (to increase vacuum at the vacuum wand). With some of the influent valves closed, the volume of the water in the system may change significantly, causing new values for Vprime  31 , Tstart  33  and Vmaint  35 . Because of the nature of vacuuming the pool, the vacuum spikes  36  are also larger, hence the larger Vmaint+  37  and Vmaint−  39  margin. However, since a complete blockage  41  causes even larger spikes  43  than vacuuming, the pool or spa is still protected from an accidental entrapment. Those values are all determined automatically after installation in the calibration process. 
     In addition, a new parameter, Tmaintmax  49 , sets the maximum amount of time the system may be in maintenance bypass mode. That prevents the system from accidentally being left in maintenance bypass mode, reducing (but not eliminating) the safety factor of the Stingl-Switch. The audio and visual alarm also activates intermittently to remind both operators and guests that the system is not in full safe mode. 
     As shown in FIGS. 3-6, the Stingl-Switch  50  is also equipped with an autostart function. That mode is selected from a switch inside the control box  51 . When activated, the pump automatically starts when power is applied to the pump control box  51 . That option is desirable for installations where the pump must be started without human intervention (the pump is controlled by an external time clock, or areas where power is frequently lost, etc.). The front panel  54  may be connected by hinges  52  to the pump control box  51 . 
     All functions of the Stingl-Switch are provided by an intelligent microprocessor  53  (FIGS.  5  and  6 ). Calibration values are stored in non-volatile EEPROM memory to prevent loss during power failures or intentional disconnects. 
     Connections  55  are provided for attachment of optional external audio and visual alarms. 
     The front panel  54  has the following switches  57 : off  61 , vacuum  63 , on  65  and edit switches  66 ,  67 ,  68  and  69 . The off switch  61  turns the pump and alarm off. The vacuum switch  63  turns the pump on for pool vacuuming (alarm sounds intermittently). The on switch  65  starts the pump. Alarms sound while the safety feature is disabled during the start sequence. The edit switches  66 ,  67 ,  68  and  69  are used for viewing and editing parameters in the 7-element LED display  71 . 
     Internal switches  73 , shown in FIG. 4, are mounted on the back cover  75  of the logic board. The calibrate switch  77  is pressed to initiate an automatic calibration sequence. The autostart switch  79  is pressed to request the pump to automatically start when power is applied to the system. When the autostart switch  79  is in the on position, starting the pump does not require an operator to manually press the on switch  65 . 
     Lights are shown on the box cover front panel  54 . The alert light  81  is a red LED that provides alarm indication and blinks when blockage is detected until manually reset. Various error messages are also displayed. 
     The start light  83  is a green LED that indicates that the motor is running and that the safety feature is enabled. The start light  83  blinks once per second while the system pump is starting and is also used after calibration to count out the vacuum set point. 
     The vacuum light  85  is a green LED that indicates when the system is in vacuum bypass mode. 
     The two-digit display  71  displays various parameters. 
     An external bright strobe light  87  flashes in synchronization with the red LED alert light  81  above. 
     The red LED alert light  81  and audible sounds are synchronized. Flash sequences of light  81  may be replaced with distinct two-digit error codes. 
     A constant flash of light (flash-flash-flash-flash) indicates that entrapment has occurred and that the Stingl-Switch has tripped. 
     A single flash with a pause (flash-pause-flash-pause) indicates that the system is in a start cycle and that the pump is priming so the safety mode is bypassed. The system automatically turns itself off after 30 seconds if prime does not occur. 
     Two flashes with a pause (flash-flash-pause-flash-flash-pause) indicates that the system is in vacuum bypass mode and the safety mode is bypassed. The system automatically turns off after 30 minutes if left in the vacuum mode. 
     Three flashes with a pause (flash-flash-flash-pause-flash-flash-flash-pause indicates that the system failed to prime in the calibrated time in the autostart mode. 
     Four flashes with a pause (flash-flash-flash-flash-pause-flash-flash-flash-flash-pause) indicates that the vacuum bypass has exceeded 30 minutes and that the system has shut itself down automatically. 
     To start the system, press the on switch  65 . The green lamp  83  over the on switch  65  blinks as the pump primes. The red lamp  81  blinks to indicate that the pump is priming. The green lamp  83  stays on when the pump primes and the system is “armed.” All other lights go out at that time. 
     To stop the system, press the off switch. All lights will extinguish, and the pump stops. 
     To vacuum, the system must be in the off mode. Once the system is in the off position, press the vacuum switch  63 . The green lamp  83  over the on switch  65  blinks as the pump  120  primes, drawing water in through suction line  121  and pumping water out through discharge line  122 . The red lamp  81 , the green lamp  83  over the on switch  65  and the green lamp  85  over the vacuum switch  63  blink to indicate the start sequence (like in the system start-up sequence above). The green lamps  83  and  85  over the on and vacuum switches  65  and  63 , respectively, stay on after the pump has successfully primed. The red lamp  81  blinks to indicate that the safety mode is bypassed. The system stays in the vacuum mode a maximum of 30 minutes before automatically shutting itself off. 
     In an entrapment situation, the system senses the entrapment and automatically shuts off the pump and sounds alarms. Once the obstruction is cleared from the drain or skimmer, press the off switch  61  to reset the system. Press the on switch  65  to start the system, as described in the start-up sequence above. The system must be manually reset after an entrapment by pressing the off switch  61 , whether the regular or autostart feature is enabled. 
     Calibration of the system must be done after installation. Press the calibrate switch  77  on the inside of the pump control box  51 . The calibrate switch  77  is inside to prevent accidental unauthorized operation. The system performs a start sequence as if in autostart mode. The microprocessor calculates the proper safe vacuum level from the measured normal vacuum level and determines the amount of time required for normal priming of the pump. During calibration, the alarm sounds to indicated that the safety feature has not yet been activated. Failing to calibrate the system at first power on will cause the red lamp  81  to flash an error message, and the system will not operate. When calibration is complete, the green lamp  83  over the on switch  65  will blink to display the calculated safe vacuum level. For example, eleven flashes and a pause indicates that the safe vacuum level is set at eleven inches of Hg. To start the system, press the off switch  61  and then start the system as described above. 
     The system is installed in the following steps: 
     Mount the pump control box  51  in a convenient location near the pump. Connect the vacuum sensor  113  to the port on the influent side of the pump, using a T-fitting if appropriate. Route wires from the sensor  113 , through the grommet  91  in the pump control box  51 . Connect the wires from the sensor  113  to the appropriate terminals  55 . Disconnect power lines to the pump. Connect power from the circuit supply to the input terminals  93  on the high voltage board  95  as marked. Connect the pump to the output terminals  93  on the high voltage board  95  as marked. The standard Stingl-Switch is equipped for 110V and 220V operation. Jumper appropriately for 110V or 220V operation. 
     Install the external light  114  and siren box  97 . Route the low voltage wires through the grommet  91 . Connect to the appropriate terminals  55  on the high voltage board  95 . 
     Select autostart mode off or on by the switch  79  on the back  75  of the logic board  99 . Use the on mode for installations where pumps are controlled by an external timer or controller, or where power to the system is frequently lost. In the off mode, the pump will turn off at power failure and will not restart without human intervention. 
     Restore power to system. Press the calibrate  77  switch inside the pump control box  50 . The system will perform an automatic calibration sequence, determining the proper safe vacuum level and the normal time to prime, and will store the profile  10  of time from timer  123  and pressure from sensor  113  in memory  125 . The stored normal operating profile  10  and vacuuming profile  30  are compared with real time pressure signals from sensor  113  and time from timer  123  in comparator  127 . After calibration, the green lamp  83  over the on switch  65  will flash to indicate the calculated safe vacuum level. The alarm  115  will sound during calibration to indicate that the safety system has not been enabled. Press the off switch  61  to leave the calibration mode. Installation of the system is now complete. 
     For maintenance work, unintended pump shutdowns may be prevented by using the vacuum mode. When in this mode however, the safety feature of the Stingl-Switch is reduced, so lights and alarms will sound to remind maintenance engineers to reset the safety feature when maintenance is complete. For safety reasons, the Stingl-Switch will disable the vacuum mode automatically after 30 minutes and signal that situation. 
     The logic for the Stingl-Switch is divided between the logic board  99  and the high voltage board  95 . The high voltage board  95 , as the name implies, incorporates all of the high voltage in the system, keeping it safely away from the low voltage logic board  99  and the operator switch panel  101 . A tap of 120VAC or 220VAC is transformed to 12VDC by transformer  111  to provide power for the coil on the power relay  103  and the alarm relay  105 , as well as offboard power to the logic board  99 . 
     The power relay  103  is rated for  20  amps per line. The power relay  103  is connected between the supply voltage and the pump via a terminal strip. The power relay is controlled directly by the logic board  99 . 
     The alarm relay  105  switches 12 volts DC to the external siren  115  and light under control of the logic board  99 . Terminals  55  are provided for easy hookup of the external light and siren panel  97 . 
     The logic board  99  contains all of the low-voltage devices in the system: the three front panel push switches  61 ,  63  and  65 ; the autostart toggle switch  79 ; three LEDs  81 ,  83  and  85 ; a piezoelectric beeper  107 , the microcontroller  53 ; associated circuitry; and the low voltage power supply  109 . A small cable connects the logic board  99  to the high voltage board  95 . 
     While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.