Method and apparatus for selectively shutting off the flow of water to a building

For use in a building having a water supply pipe through which water is supplied to this building, water flowing in a first forward direction through the water supply pipe when water is being used in the building, the direction opposite to the first forward direction being a second backflow direction, the building having an electric water heater that is supplied with electrical power from an electrical panel and supplied with water from the water supply pipe, an apparatus for selectively interrupting the flow of water through the water supply pipe comprising:

• at least one flow sensor for detecting flow of water at least in the first of the first and second directions, the sensor providing a water flow output indicating signal corresponding to the direction of water flow;
• a flow monitoring circuit coupled to the at least one flow sensor so as to receive the water flow output indicating signal, the flow monitoring circuit being adapted to provide a valve close signal in the event water flow in at least the first direction is equal to or exceeds a first forward flow threshold;
• a valve coupled to the flow monitoring circuit and adapted to interrupt the flow of water through the water supply pipe in response to the valve close signal;
• wherein the at least one flow sensor detects the flow of water in the first and second directions, the flow monitoring circuit also being adapted to provide a valve close signal in the event water flow in at least the second direction is equal to or exceeds a second back flow threshold;
• the apparatus further comprising an electrical switch that, in response to a power off signal, is adapted to shut off the electrical power to the water heater, the flow monitoring circuit being coupled to the electrical switch and being adapted to provide the power off signal to the electrical switch in the event the flow of water through the water supply pipe has been interrupted in response to the valve close signal;
• wherein the first and second thresholds are each time thresholds;
• wherein the flow monitoring circuit comprises an excessive forward flow determiner circuit for receiving a water flow output signal from the at least one flow sensor corresponding to forward flow of water, the excessive forward flow determiner monitoring the duration of time during which forward flow of water continuously exists, the excessive forward flow determiner providing a first excess forward flow signal corresponding to the first forward flow threshold when the duration of the continuous forward flow of water at least equals the forward flow threshold;
• the flow monitoring circuit also comprising an excessive backflow determiner circuit for receiving a water flow output signal from the at least one flow sensor corresponding to backflow of water, the excessive backflow determiner monitoring the duration of time during which backflow of water continuously exists, the excessive backflow determiner providing a second excess backflow signal corresponding to the second backflow threshold when the duration of the continuous back flow of water at least equals the back flow threshold;
• and
• the flow monitoring circuit also comprising a controller circuit coupled to the excessive forward flow determiner circuit and to the excessive backflow determiner circuit for receiving the respective first excessive forward flow signal and second excessive backflow signal, the controller being coupled to the valve and being operable to provide the valve close signal in the event water flow at least in the first direction exceeds the first forward flow threshold and in the event water flow in the second direction exceeds the second backflow threshold.

An apparatus for selectively interrupting the delivery of power from an electrical panel to an electric water heater and for controlling the flow of water through a building water supply pipe, the apparatus comprising:

• a flow direction detector adapted to determine the direction of flow of water in the water supply pipe in a first forward direction and in a second backflow direction;
• a flow direction determiner coupled to the flow direction detector and operable to provide at least one control signal in the event at least one of undesirable forward flow and undesirable back flow of water is determined;
• a controller coupled to the flow direction determiner for receiving at least one control signal, the controller being adapted to provide a valve close signal in response to the occurrence of the at least one control signal;
• a valve coupled to the controller and adapted to interrupt the flow of water through the water supply pipe in response to the valve close signal;
• and
• an electrical switch adapted to shut off the electrical power to the water heater in response to a power off signal, the controller being coupled to the electrical switch and being adapted to cause the delivery of the power off signal to the electrical switch in the event the flow of water through the water flow pipe has been interrupted in response to the valve close signal.

An apparatus comprising:

• means for detecting the forward flow and backflow of water through a building water supply pipe;
• means for interrupting the flow of water through the building water supply pipe upon detection of the forward flow of water through the building water supply pipe for at least a first continuous time period and for interrupting the flow of water to the building through the building water supply pipe upon detection of the backward flow of water for at least a second continuous time period;
• and
• means for interrupting the power to a water heater for the building in the event the flow of water through the building water supply pipe is interrupted due to at least one of the forward flow of water through the building water supply pipe for at least a first continuous time period and the backflow of water through the building water supply pipe for at least a second continuous time period, the first continuous time period being greater than the second continuous time period.