Abstract:
A plumbing system operable to automatically introduce antifreeze into the hot and cold water systems responsive to a signal from a controller. The controller activates the system automatically at a predetermined ambient temperature. The system can also be reconfigured manually.

Description:
This invention is related to domestic plumbing systems, and in particular to an apparatus and method for protecting a home or other building from the extensive damage that can result from the freezing and resulting bursting of pipes within walls and ceilings of a building. 
     A typical domestic plumbing system receives water from a municipal supply system or a well, and then distributes the water as hot and cold water to fixtures throughout the house. The piping that makes up the plumbing system is installed within the walls and ceilings of the building for cosmetic purposes. Such systems work very well, and provide reliable service under most conditions. One potential problem with such systems arises if and when the heating system in the building fails, and the internal temperature of the building falls below freezing. If this occurs while the building is unoccupied, the pipes can freeze and burst, causing extensive damage to the building. The damage can be particularly severe if the water service to the building has not been turned off at the supply valve, in which case water will continue to flow into the building until the leak is discovered hours or even days later. 
     This invention addresses this problem by providing a plumbing system that includes an antifreeze dispensing apparatus that can be activated to inject a predetermined amount of antifreeze into the plumbing system and prevent the freezing of the pipes and fixtures. The antifreeze is a nontoxic antifreeze that is approved for domestic use, and that can be readily flushed from the system using only fresh water form the normal supply. In another aspect of the invention, the apparatus senses when the temperature in the building has dropped to freezing and automatically shuts the water supply valve to the plumbing system. These and other features of the invention will be described in greater detail be reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing of a typical domestic plumbing system including various domestic appliances and fixtures, and the required hot and cold water supply lines. 
         FIG. 2  is a schematic drawing of a domestic plumbing system according to a preferred embodiment of the present invention. 
         FIG. 3  is a front view of a system controller. 
         FIG. 4  is an enlarged perspective view of connections between the bypass valve assembly, the water heater and the water supply shown in  FIG. 1 . 
         FIG. 5  is a partial cut away view of the 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Turning now to  FIG. 1 , a typical domestic plumbing system includes a water supply  10 , a water supply cut-off valve  12 , backflow preventer, and separate hot and cold water supply piping systems  14  and  16  respectively. The hot water system  14  includes a hot water heater  18 , a cold water supply  20  to the water heater  18 , and a hot water supply piping system to supply hot water to appliances such as the dishwasher  22 , clothes washer  24 , sinks  26  in the bathrooms and kitchen, and bathtubs  28 . The cold water supply piping system  16  supplies cold water to each of these same appliances and fixtures, and also to toilets  30  and hose bibs  32 . 
     In one preferred embodiment of the invention, a freeze protection system includes, in addition to the components enumerated for the typical domestic plumbing system, a cold water supply valve controller  34 , an antifreeze storage tank assembly  36 , a bypass valve assembly  38 , and a controller assembly  40 . The water supply valve controller  34  includes a water supply shut off valve (not shown). An antifreeze supply line  42  connects water supply valve controller  34  to the antifreeze storage tank assembly  36 . The antifreeze storage tank assembly  36  includes a pump (not shown) to dispense antifreeze within the storage tank assembly  36  through line  42  to the water supply controller valve  34  and into the water supply line  35 . The pump is preferably a low voltage pump that is supplied with low-voltage current from a transformer connected to the building&#39;s electrical system (not shown) under normal operation. In the event of a power outage, the storage tank assembly  42  includes a backup battery (not shown) for operating the pump. 
     Referring to  FIGS. 4 and 5 , bypass valve assembly  38  includes an electrically operated three-way valve that can be configured to direct a supply of cold water into the water heater  18  under normal operation, and to bypass the water heater  18  and redirect cold water directly into the hot water piping system  16 . Bypass valve  38  in the preferred embodiment is a three way ball valve with its inlet  39  connected to the cold water inlet line from the water supply controller valve  34 . One outlet  41  of bypass valve  38  directs cold water to the hot water heater  18  under normal conditions. A second outlet  43  directs cold water to bypass water heater  18  and go directly into the hot water system of the building. This configuration is used to introduce antifreeze into the hot water system of the building. A check valve  51  is installed between the water heater hot water outlet  53  and bypass valve  38  to prevent backflow into the water heater discharge from the bypass valve. Referring to  FIG. 5 , bypass valve  38  includes a ball assembly  45  that is rotated between the first and second configurations by actuator  47 . Actuator  47  is connected by wires  49  to controller assembly  40 , which operates the bypass valve as described below. 
     The controller assembly  40  is preferably an electronic as shown  FIG. 3 . Controller  40  includes an outside temperature monitor  42 , an antifreeze level indicator  44 , an inside temperature monitor  46 , a switch  48  to initiate the winterization process, a switch  50  to activate the bypass valve assembly  38 , a switch  52  to activate the battery backup for antifreeze injection pump, and a water damage control switch  54  to activate the water. supply controller valve  34  in order to isolate the plumbing system from the water supply system if temperatures drop to −30° F. 
     The operation of the system will now be described. Under normal operation, water supply controller  34  directs water from the water supply system to the plumbing system. Cold water is directed into the cold water piping system  16 , and also through bypass valve assembly  38 , hot water heater  18  and into the hot water piping system  14 . 
     When the building is going to be unoccupied for a period of time in which it would be possible for the plumbing system to be exposed to freezing temperatures, the user presses the bypass switch  50 , followed by the winterize switch  48 . The system is activated to configure bypass valve assembly  38  to redirect water away from the hot water heater and directly into the hot water piping system  14 . The system then activates the antifreeze pump to supply antifreeze from storage tank assembly  42  to the water supply controller, which injects the antifreeze into the water entering the plumbing system of the building. Water valves on the appliances and fixtures are then opened to permit the water/antifreeze solution to flow through and fill the plumbing system, and are then closed. The hot and cold water piping systems are then protected from freezing temperatures. Applicant has found that a ratio of 50% propylene glycol is suitable for protecting the system to a temperature of about −50 F. A higher concentration of antifreeze can be obtained by adjusting the water supply controller  34  to inject a greater amount of antifreeze into the water entering the system. In this way the system can be protected to a temperature of −60° F. Once the plumbing system has been flushed with the antifreeze mixture, the valves on the appliances and fixtures are closed. The water supply controller  34  is then activated again, and shuts the water supply valve, protecting the system in the event of a leak in the system during the owner&#39;s absence. The winterize injection switch also deactivates the pump in the antifreeze storage assembly  36 . The water heater can be turned off and drained since it is isolated from the rest of the system. 
     When the building is to be reoccupied, the bypass switch  50  is activated, configuring the bypass valve  38  to its bypass operating configuration. The winterize switch  48  is activated to normal flow to open the water supply valve. The water valves at each appliance are opened to permit fresh water to completely flush the antifreeze from the system in preparation for normal use of the building. After flushing is complete, the bypass  50  is activated to normal flow position and the water heater will fill at this time. 
     In the preferred embodiment the system is activated and controlled by a 12 volt electrical system. In other embodiments some or all of the system configuration and activation can be done manually. 
     Some functions of the system can be activated individually. For example, if the building is to be unoccupied, but freezing is not a concern the water damage control switch  54  can be activated to shut off the water supply to the building while unoccupied. If it is necessary to service the water heater, the bypass valve can be operated separately to isolate the water heater from the rest of the system. Finally, if power to the building is interrupted, the water damage control  54  will activate closing the flow of water supply. 
     The antifreeze solution can be any suitable solution approved for domestic potable water systems. Applicant has identified prop glycol, available from Dow Chemical, as one such preferred antifreeze solution. 
     While the invention has been described by reference to the foregoing preferred embodiments, the invention is not intended to be limited thereby. Those of skill in the art will understand that numerous modifications and variations are possible without departing from the scope of the following claims.