Battery-powered hot water recirculation pump

Abstract

A relatively small water pump-DC motor combination, powered by batteries, provides sufficient pump power to create the flow between the hot and cold water lines necessary to maintain a substantially immediate hot water response when the hot water tap is opened. The pump is controlled by a thermal sensor signaling the pump to commence operation when the temperature in the hot water line upstream of the hot water tap is less than a predetermined value. Preferably, each of the batteries is rechargeable, most preferably utilizing a wireless system, where the power source is a distance away from the pump battery, to provide additional protection against electrical short circuits in the presence of water. Commonly available batteries of between 10 and 24 Volts can be used.

What is claimed is: 
     
         1 . A battery-powered motor-pump combination to promptly provide for a building hot water system hot water at every tap following lengthy periods of nonuse, the pump system comprising:
 a time controller for the motor-pump combination;   a centrifugal pump impeller and casing, the casing having a water inlet and a water outlet;   an electrical power storage unit;   a DC electric motor, controlled by the timer controller, electrically connected to the battery and able to be powered by the chemical battery and mechanically connected to the centrifugal pump impeller to provide the power to operate the pump combination;   the pump system being designed to be connected by the water inlet to the pressurized hot water line in the building, upstream of a hot water tap, and designed to being connected by the water outlet to the pressurized cold water line in the building, upstream of a cold water tap;   the pump system designed when operating to recirculate hot water from the hot water line into the cold water line in response to commands from the time controller to turn on and off the electric motor and thus cause the impeller to turn and stop,   
     
     
         2 . The battery-powered motor-pump combination of  claim 1  wherein the electrical power storage unit is a chemical storage battery. 
     
     
         3 . The battery-powered motor-pump combination of  claim 2  wherein the storage battery is rechargable, and further comprising an electric charger to recharge the storage battery when the storage battery loses sufficient charge so that it cannot effectively power the motor 
     
     
         4 . The battery-powered motor-pump combination of  claim 2  wherein the charger comprises a power lead designed to receive electrical power from a house wall socket. 
     
     
         5 . The battery-powered motor-pump combination of  claim 2 , further comprising a broadcast power receiver designed to receive broadcast power from a correspondingly tuned power broadcast transmitter located at a distance from the battery-powered motor-pump combination and electrically connected to the charger so as to provide power to the charger for recharging the storage battery. 
     
     
         6 . The battery-powered motor-pump combination of  claim 2 , further comprising a thermistor operatively connected to the time controller and to the motor-pump combination, so as to prevent increasing the temperature in a hot water line beyond a preset value. 
     
     
         7 . A battery-powered pump system for a building hot water system to promptly provide hot water at every tap, following lengthy periods of nonuse, the pump system comprising:
 a time controller for the pump system;   a centrifugal pump impeller and casing, the casing having a water inlet and a water outlet;   a storage battery;   a DC electric motor, controlled by the timer controller, electrically connected to the battery and able to be powered by the chemical battery and mechanically connected to the centrifugal pump impeller to provide the power to operate the pump system;   a pressurized hot water line in the building and a pressurized cold water line in the building;   the pump system being connected by the water inlet to the hot water line, upstream of a hot water tap and being connected by the water outlet to the cold water line, upstream of a cold water tap;   the pump system operating to recirculate hot water from the hot water line into the cold water line in response to commands from the timer controller to turn on and off the electric motor and thus cause the impeller to turn and stop.   
     
     
         8 . The pump system of  claim 7  further comprising a signal interface circuit, a thermistor, and an automatic operation switch, the signal interface circuit coupling the thermistor, and automatic operation switch to the timer controller for controlling the operation of the pump system, the thermistor being capable of over-riding the switches to limit the temperature in the hot water line upstream from the hot water tap. 
     
     
         9 . The pump system of  claim 7  where the battery has an electrical voltage rating of between 10 and 24 volts. 
     
     
         10 . The pump system of  claim 7 , further comprising a compact casing for the pump system, the battery being integrated with and housed within the compact casing for the water pump system. 
     
     
         11 . The pump system of  claim 5 , wherein the pump motor comprises a rotor formed of permanent magnets and a wire-wound stator electrically connected to the battery 
     
     
         12 . The pump system of  claim 5 , wherein the electric motor can operate on at least 5 Watts power, and provides a maximum pressure head of at least 5 ft of pressure head and a maximum flow output of at least 5 gpm. 
     
     
         13 . A wireless pump system for a building hot water system to promptly provide hot water at every tap, following lengthy periods of nonuse, the pump system comprising:
 a time controller for the pump system;   a centrifugal pump impeller and casing, the casing having a water inlet and a water outlet, the pump impeller being wholly encompassed within the casing;   a rechargeable electrical storage battery;   a DC electric motor, controlled by the timer controller, electrically connected to the battery and able to be powered by the storage battery and mechanically connected to the centrifugal pump impeller to provide the power to operate the pump system;   a pressurized hot water line in the building and a pressurized cold water line in the building;   the pump system being connected by the water inlet to the hot water line, upstream of a hot water tap and being connected by the water outlet to the cold water line, upstream of a cold water tap;   a charger unit electrically connected to the storage battery and operating from time to time to recharge the battery; and   a wirelessly broadcast power receiver, in electrical connection with the charger unit, the wirelessly broadcast power receiver receiving power broadcast from a power broadcaster located at a distance from the receiver, the receiver being adjacent the charger and the pump motor;   the pump system operating to recirculate hot water from the hot water line into the cold water line in response to commands from the timer controller to turn on and off the electric motor and thus cause the impeller to turn and stop, and the charger capable of receiving broadcast power and recharging the storage battery as needed.   
     
     
         14 . The wireless pump system of  claim 12  further comprising a compact casing encompassing the complete wireless pump system. 
     
     
         15 . The wireless pump system of  claim 13 , wherein the rotor is mechanically directly connected to the pump impeller. 
     
     
         16 . The wireless pump system of  claim 13 , wherein the pump motor comprises a rotor formed of permanent magnets and a wire-wound stator electrically connected to the battery. 
     
     
         17 . The wireless pump system of  claim 12 , wherein the electric motor can operate on at least 5 Watts power, to provide a maximum pressure head of at least 5 ft of pressure head and a maximum flow output of at least 5 gpm. 
     
     
         18 . The pump system of  claim 12 , further comprising a compact casing for the pump system, the battery, charger and broadcast power receiver being integrated with and housed within the compact casing for the water pump system. 
     
     
         19 . A building water flow system that provides substantially instantaneous hot water from hot water taps without regard to the length of time between use, the system comprising:
 a source of hot water; multiple hot water taps; and a closed piping system providing a fluid flow connection between the source of hot water and each of the multiple hot water taps; a source of ambient water; multiple ambient water taps located adjacent at least the hot water tap located the furthest front the source of hot water; and a closed piping system providing a fluid flow connection between the source of ambient water and each of the is multiple ambient water taps, and between the source of ambient water and the source of hot water; a battery-powered motor-pump combination comprising:   a time controller for the motor-pump combination;   a centrifugal pump impeller and casing, the casing having a water inlet and a water outlet;   an electrical storage battery;   a DC electric motor, controlled by the timer controller, electrically connected to the battery and able to be powered by the chemical battery and mechanically connected to the centrifugal pump impeller to provide the power to operate the pump combination;   the water inlet being connected to the pressurized hot water line in the building, upstream of a hot water tap the furthest from the source of hot water, and the water outlet being connected to the pressurized cold water line in the building, upstream of the cold water tap adjacent the furthest hot water tap;   the pump system being designed to recirculate hot water from the hot water line into the cold water line in response to commands from the timer controller to turn on and off the electric motor and thus cause the impeller to turn and stop, thus constantly refreshing the hot water in the hot water line.   
     
     
         20 . The building water flow system of  claim 18  wherein the storage battery is rechargable, and further comprising an electric charger to recharge the storage battery when the storage battery loses sufficient charge so that it cannot effectively power the motor, a broadcast power transmitter and a broadcast power receiver designed to receive broadcast power from a correspondingly tuned power broadcast transmitter located, at a distance from the battery-powered motor-pump combination and electrically connected to the charger so as to provide power to the charger for recharging the storage battery.