Circulating system for providing instant hot water

Abstract

A water circulating system is for distributing instant hot water at a fixture that has respective hot and cold water inlets. The system includes hot and cold water piping, a pump constructed and arranged to pump water through said hot water piping. A by-pass device is provided at the sink area and connected directly between the hot water inlet and the cold water inlet. The by-pass device includes a pump for drawing hot water, a thermal switch, and a check valve. The pump, thermal switch, and check valve are constructed and arranged in series. A controller is connected to the pump so as to control the duty cycle of the pump so as to establish at least one of a selectable pump cycle time, and a selectable pump running time.

What is claimed is: 
     
         1 . A water circulating system for distributing water, comprising:
 a fixture configured for utilizing hot and cold water, said fixture having a hot water inlet and a cold water inlet and disposed at a sink area;   a hot water heater for supplying hot water to said fixture;   hot water piping interconnecting said hot water heater with said hot water inlet at said fixture;   a source of cold water for supplying cold water to said fixture and said hot water heater;   cold water piping interconnecting said source of cold water with said cold water inlet at said fixture;   a by-pass device at the sink area and connected directly between the hot water inlet and the cold water inlet;   said by-pass device including a pump for drawing hot water, a thermal switch, and a check valve;   the pump, thermal switch, and check valve being constructed and arranged in series;   and a controller including at least one of a first manually selectable control input that establishes a selectable pump cycle time, and a second manually selectable control input that establishes a selectable pump running time.   
     
     
         2 . The system of  claim 1  wherein the check valve has a predetermined cracking pressure and is a uni-lateral valve allowing flow in only one direction therethrough. 
     
     
         3 . The system of  claim 2  wherein the cracking pressure is equal to or greater than the pressure drop at the cold water inlet caused by the velocity head thereat when the cold water is drawn. 
     
     
         4 . The system of  claim 3  wherein in an open position of the check valve the pump pressure is greater than the check valve cracking pressure. 
     
     
         5 . The system of  claim 2  wherein in an open position of the check valve the pump pressure is greater than the check valve cracking pressure. 
     
     
         6 . The system of  claim 1  wherein the controller is an electrical controller operated from an AC voltage, and the pump plugs into the electrical controller, both inputs are selectable, and the first and second inputs are each comprised of a control dial. 
     
     
         7 . The system of  claim 1  wherein the thermal switch comprises a switch that is responsive to water temperature, and including a control line from the switch to control the operation of the pump. 
     
     
         8 . The system of  claim 7  wherein the thermal switch comprises a bi-metal switch having enable and inhibit positions. 
     
     
         9 . The system of  claim 8  wherein the thermal switch controls the pump via the control line to turn the pump on when in the enable position and to turn the pump off when in the inhibit position. 
     
     
         10 . A method of controlling the delivery of essentially instant hot water at a fixture configured for utilizing hot and cold water, said fixture having a hot water inlet and a cold water inlet, and a hot water heater for supplying hot water to said fixture, supplying cold water to the fixture, providing a by-pass device including a pump for drawing hot water, a thermal switch, and a check valve, wherein the pump, thermal switch, and check valve being constructed and arranged in series, pumping hot water through the by-pass device to maintain how water at the hot water outlet, connecting an electrical controller to the pump so as to control the duty cycle of the pump so as to establish at least one of a selectable pump cycle time, and a selectable pump running time. 
     
     
         11 . The method of  claim 10  including the check valve with a predetermined cracking pressure and wherein the check valve is a uni-lateral valve allowing flow in only one direction therethrough. 
     
     
         12 . The method of  claim 11  wherein the cracking pressure is equal to or greater than the pressure drop at the cold water inlet caused by the velocity head thereat when the cold water is drawn. 
     
     
         13 . The method of  claim 11  wherein in an open position of the check valve the pump pressure is greater than the check valve cracking pressure. 
     
     
         14 . The method of  claim 10  wherein the controller is an electrical controller operated from an AC voltage, and the pump plugs into the electrical controller, both inputs are selectable, and the first and second inputs are each comprised of a control dial. 
     
     
         15 . The method of  claim 11  wherein the thermal switch comprises a switch that is responsive to water temperature, and including a control line from the switch to control the operation of the pump. 
     
     
         16 . The method of  claim 11 thermal switch comprises a bi-metal switch having enable and inhibit positions, and wherein the thermal switch controls the pump via the control line to turn the pump on when in the enable position and to turn the pump off when in the inhibit position. 
     
     
         17 . In a water circulating system for distributing instant hot water at a fixture that has respective hot and cold water inlets, comprising hot and cold water piping, a pump constructed and arranged to pump water through said hot water piping, a by-pass device at the sink area and connected directly between the hot water inlet and the cold water inlet; said by-pass device including a pump for drawing hot water, a thermal switch, and a check valve; the pump, thermal switch, and check valve being constructed and arranged in series; and a controller connected to the pump so as to control the duty cycle of the pump so as to establish at least one of a selectable pump cycle time, and a selectable pump running time. 
     
     
         18 . The system of  claim 17  wherein the thermal switch comprises a switch that is responsive to water temperature, and including a control line from the switch to control the operation of the pump. 
     
     
         19 . The system of  claim 18  wherein the thermal switch comprises a bi-metal switch having enable and inhibit positions. 
     
     
         20 . The system of  claim 19  wherein the thermal switch controls the pump via the control line to turn the pump on when in the enable position and to turn the pump off when in the inhibit position.