Method and apparatus for improving the performance of suction powered pool cleaning systems

Abstract

A pool cleaning system including means responsive to the magnitude of negative pressure at the suction inlet of a system pump for controlling pump water flow in order to prevent pump cavitation. Systems in accordance with the invention are configured to pump a high rated volume of water when operating in a filtering mode and to provide a high negative pressure to power a pool cleaner when operating in a cleaning mode.

1 . A method of operating a pool cleaning system comprised of a water pump, suction side plumbing coupling a pool water inlet to a suction inlet of said pump, and pressure side plumbing coupling a pressure outlet of said pump through a filter to a pool water return outlet, said method comprising:
 sensing the pressure at a site at the suction side of said pump; and   responding to said sensed pressure for controlling water flow from said pump outlet.   
     
     
         2 . The method of  claim 1  further including:
 setting a setpoint for pressure at said site; and   responding to a sensed pressure more negative then said setpoint for reducing water flow from said pump outlet.   
     
     
         3 . The method of  claim 1  further including:
 setting a setpoint for pressure at said site; and   responding to a sensed pressure more positive then said setpoint for increasing water flow from said pump outlet.   
     
     
         4 . In a system for cleaning a water pool including:
 a pump having a suction inlet and a pressure outlet;   pressure side plumbing including a filter coupling said pressure outlet to at least one pool return outlet;   means defining a pool water inlet;   a pool cleaner configured to be powered by suction for traveling through said water pool; and   suction side plumbing including a first flow path coupling said pump suction inlet to said pool water inlet and a second flow path coupling said pump suction inlet to said pool cleaner;   the improvement comprising:   a flow controller responsive to the pressure at the suction side of said pump for controlling output flow from said pump to prevent pump cavitation.   
     
     
         5 . The system of  claim 4  further including:
 a pressure sensor for monitoring pressure at a site at the suction side of said pump; and wherein   said flow controller is responsive to said monitored pressure being more negative than a setpoint for reducing the output flow from said pump.   
     
     
         6 . The system of  claim 5  wherein said flow controller operates to reduce said output flow by increasing the flow resistance at the pressure side of said pump. 
     
     
         7 . The system of  claim 5  wherein said flow controller operates to reduce said output flow by reducing the pumping capacity of said pump. 
     
     
         8 . The system of  claim 4  further including:
 a pressure sensor for monitoring pressure at a site at the suction side of said pump; and wherein   said flow controller is responsive to said monitored pressure being more positive than a setpoint for increasing the output flow from said pump.   
     
     
         9 . Apparatus for cleaning a water pool comprising:
 a pump having a suction inlet and a pressure outlet;   a skimmer/drain defining a pool water inlet and a pool water outlet coupled to said pump suction inlet;   a pool cleaner defining a pool water inlet and a pool water outlet coupled to said pump suction inlet; and   control means responsive to the pressure at the suction side of said pump for controlling water flow from said pressure outlet, said control means including:   a sensor for sensing the pressure at the suction side of said pump; and   a flow controller responsive to said sensed pressure for controlling water flow from said pump pressure outlet to maintain said sensed pressure at a predetermined level.   
     
     
         10 . The apparatus of  claim 9  wherein said pump includes a motor and said control means includes a motor control circuit connected to said motor; and wherein
 said flow controller is coupled to said motor control circuit for controlling the pumping capacity of said pump.   
     
     
         11 . In a system for cleaning a water pool contained by a wall including:
 a pump having a suction inlet and a pressure outlet;   pressure side plumbing including a filter coupling said pressure outlet to at least one pool return outlet;   a skimmer/drain defining a pool water inlet;   a pool cleaner defining a pool water inlet and configured to be powered by suction for traveling through said water pool; and   suction side plumbing including a first flow path coupling said pump suction inlet to said skimmer/drain pool water inlet and a second flow path coupling said pump suction inlet to said pool cleaner, said second flow path including a conduit extending from said suction inlet to a port in said wall and a suction hose coupling said port to said cleaner;   the improvement comprising:   a pressure sensor for monitoring the pressure proximate to said wall port; and   a flow controller responsive to said monitored pressure for controlling water flow from said pump outlet for producing a substantially constant pressure more negative than −12″ Hg at said wall port for powering said cleaner.   
     
     
         12 . The system of  claim 11  including means for adjustably establishing a pressure setpoint; and wherein
 said flow controller is responsive to said monitored pressure being more negative than said setpoint for reducing the output flow from said pump.   
     
     
         13 . The system of  claim 12  wherein said flow controller operates to reduce said output flow by increasing the flow resistance at said pressure outlet. 
     
     
         14 . The system of  claim 12  wherein said flow controller operates to reduce said output flow by reducing the pumping capacity of said pump. 
     
     
         15 . The system of  claim 11  including means for adjustably establishing a pressure setpoint; and wherein
 said flow controller is responsive to said monitored pressure being more positive than said setpoint for increasing the output flow from said pump.   
     
     
         16 . The system of  claim 15  wherein said flow controller operates to increase said output flow by reducing the flow resistance at said pressure outlet. 
     
     
         17 . The system of  claim 15  wherein said flow controller operates to increase said output flow by increasing the pumping capacity of said pump.