Abstract: Disclosed herein are storage type water heaters having means for improved mixing of cold water supply with water stored in the water tank of a water heater, means for limiting surges of water into and out of a water tank, and means for disrupting formation and propagation of convection currents and water streamers in a water tank.

Abstract: A water heating system in which the output water temperature is regulated by a mixing valve which allows the temperature of the water contained within the water heater to be maintained at a much higher temperature without compromising safety. Significantly more hot water is therefore available for use yet the maximum temperature supplied to the various points of usage are within the safe limits. The system can be additionally configured to supply unmixed hot water to points of usage where a higher temperature is needed and a user is not exposed to the water such as for example in a dishwasher.

Abstract: In a hot and cold water distribution system, cooled down water in the hot water distribution line is automatically drained toward the cold water distribution line by a connection system consisting essentially of a centrifugal pump in series with a valve oriented to prevent the flow of cold water into the hot water distribution line or of hot water into the cold water distribution line by the same valve.

Abstract: A water recirculation system is disclosed for moving water from a hot water tap to a cold water tap. The recirculation system includes a water manifold that houses a pump, solenoid, check valve and temperature switch. Water is moved between these components within the water manifold so that external piping is unnecessary.

Abstract: Apparatus for attachment to a plumbing system having a warm water outlet, for rapidly delivering hot water through the plumbing system to the warm water outlet, comprising a diverter valve attachable to a building water pipe upstream of the warm water outlet for purging cold water from the water pipe, a diverter pipe section extending from the diverter valve, a back flow preventer in flow relationship with the diverter pipe section, and a flow control regulator in flow relationship with the diverter pipe section, whereby a small controlled flow of cold water may be diverted from the water pipe to thereby cause rapid delivery of warm water to the warm water outlet when actuated.

Abstract: An integral water circulation device reliably provides rapid hot water at remote hot water faucets throughout a building by creating a low rate convective circulatory flow from the building water heater through a return line and the circulation device itself, without mixing hot and cold water within the system.

Abstract: A drain valve for a hot water heater includes a hollow tubular portion having a tapered first end with an externally threaded neck extending therefrom. The tubular portion includes a pair of diametrically opposed internally threaded ports each having a plug received therein. Either plug may be removed allowing a hot water recirculation line to be conveniently attached to the valve. The opposing end of the tubular portion includes a downwardly depending nozzle having a valve means therein operable with an externally mounted handle. The nozzle includes an externally threaded circumferential rim to which a drain conduit may be coupled for conveniently draining the water heater. Accordingly, the threaded neck may be coupled with a tap on a conventional hot water heater allowing a recirculation line to be conveniently added at a later date with minimal reconstruction of the existing piping.

Abstract: The system is unique in that a structure's plumbing lines are effectively routed, to stop energy and water waste, while adding little to construction cost. Water pressure to hot water supply (50) is controlled through a selectable flow control valve (10). A hot water manifold (3) and check valves 42 and 43 produce a dual line connection, between hot water manifold (3) and the hot water use area. In the water saver mode, positioning selectable flow control valve (10) causes pump (4) to draw water from distribution conduit (6), through selectable flow control valve (10), through cold water manifold (12) and solenoid valve (37) to hot water supply (50). Pump (4) causes hot water to fill distribution conduit (6), to the hot water use area. This circulation delivers hot water to replace water standing in the line. Circulation period is determined by controller (22).

Abstract: A water conservation system having a control element and flow regulation device, the combination of which is in series with a hot water source and water discharge outlet. The water conservation system may further, or alternatively, comprise a shunt pipe extending substantially from the hot water source to a water discharge outlet and parallel to the hot water supply pipe. When ambient or low temperature water is detected in the hot water supply pipe, the combination control element and flow regulation device may divert low temperature water to a holding tank which preferably stores the water at atmospheric pressure. The holding tank may provide make-up water to a toilet's primary water closet or be used in other areas where clean water is desired or required.

Abstract: In a hot and cold water plumbing installation, a volume of hot water is first drawn from the hot water line and stored in an insulated reservoir. When the temperature of the water near the most distal location of the hot water line falls below a predetermined level, the contents of the insulated reservoir are reinjected back into that line to flush the cooled down water back into the water heater. A second reservoir is used between the water heater inlet and the cold water source to absorb the excess water resulting from the aforesaid reinjection and prevent hot water from being injected into the cold water line.

Abstract: Tapping point including a mixer (10) for cold and hot water where the mixer (10) has a hot water inlet (20) arranged to connect to a feed pipe (64) for hot water, a cold water inlet (40) arranged to connect to a feed pipe (70) for cold water, a mixing chamber (32) for mixing hot water introduced through the hot water inlet (20) with cold water introduced through the cold water inlet (40), a space for hot water (22) between the hot water inlet and the mixing chamber (32), a space for cold water (42) between the cold water inlet (40) and the mixing chamber (32), a mixer outlet (34) for mixed water from the mixing chamber (32), and an initial valve device (30,36,50) arranged so that in an open mixing position, it allows cold water and hot water to enter into the mixing chamber (32) from their respective spaces (22,42) and exit as mixed water from the mixer outlet (34), and, in a closed mixing position, prevents the exit of mixed water from the mixer outlet (34).

Abstract: Apparatus for expelling air from a liquid storage tank, such as a hot water storage tank includes a bleed line coupled between a water circulating pump discharge conduit and a hot water discharge line emanating from tank 10. The bleed line is connected to the hot water discharge line at a location which is elevated with respect to a location where the bleed line is connected to the pump discharge conduit. The pump is operable to draw hot water from the top part of the tank and discharge it into a cold water fill line extending into the tank to enhance water circulation in the tank. Air and other gas released when water is heated in the top part of the tank are drawn from the top part of the tank and expelled via the bleed line, to prevent accumulation of air and other gas in the tank. In accordance with another aspect of the invention, an elongated tubular member is inserted into the cold water fill line.

Abstract: In a hot and cold water distribution system wherein the hot water is delivered from a water heater to a distant hot water tap adjacent to a cold water tap, a hot water recirculation pump assembly purges the hot water line of any cooled-down water in order to assure instant hot water delivery when the hot water tap is opened. The volume of water drawn from the hot water line is, in a first embodiment of the invention, cooled down through a radiator before being recirculated through the cold water line faucet. In a second embodiment, the volume of cooled down water is flushed back through the hot water line by admission of an equal volume of cold water in that line. That volume of cold water is immediately pumped back into the cold water line, and automatically replaced by hot water drawn from the water heater. Each embodiments prevent any drawing of lukewarm water from the cold water tap. The pump assembly includes a pressure-sensitive check-valve in the pressure region of each pump.

Abstract: A hot water distribution system incorporating a pump positioned close to, and between each set of hot and cold water taps to which periodically move the cooled-down water content of the hot water distribution line through the cold water distribution line back to the hot water tank until the total content of the hot water line has a predetermined temperature. The pump is provided with a valve responsive to pump-generated pressure to prevent backflow when the pump is not in use and the pressure in the cold water distribution line is lower than the pressure in the hot water distribution line, such as when water is drawn through a cold water tap.

Abstract: An integral water circulation apparatus supplies instant hot water at hot water faucets remotely located from the building water heater through a convective circulation flow of hot water from the water heater It is therefore simpler in design, less expensive to install, and more reliable than the more complex prior art systems.

Abstract: A regulator for maintaining a constant partial vacuum in a region, such as in a piece of process equipment or a fume hood. The regulator includes a path, through which fluid passes from the region to the vacuum source, and a movably mounted piston having a frontal face, which is exposed to fluid in the path, and a distal face, which is exposed to a reference pressure, such as the pressure of the environment in which the equipment is located. The piston is disposed in the path so that the piston may constrict the path at a constriction point. Fluid in the path upstream of the constriction point exerts a pressure on the frontal face of the piston that tends widen the path at the constriction point. The piston is mounted so that the weight of the piston exerts a force on the piston in a direction that tends to widen the path at the constriction point. A force is exerted on the piston, preferably by a spring under compression, in a direction that tends to narrow the path at the constriction point.

Abstract: A zone valve hot water recirculation system in accordance with the present invention generally includes a hot water source, such as an electric or gas water heater, a conduit for enabling circulation of hot water from hot water source to one or more plumbing fixtures and recovery of water to the hot water source, a pump for accelerating delivery of hot water to the fixtures and, importantly, a zone valve for preventing flow of water into the hot water source during standby periods of the hot water source. A controller, which may include an electronic timer, is provided for causing the zone valve to open and close and the pump to start and stop.

Abstract: A convective flow control device that can maintain hot water at hot water pipe connections at remotely located faucets in homes and buildings. The convective flow device has a two part housing that encloses a dual purpose poppet in an internal circular bored chamber formed by the two piece housing. The said internal circular bored chamber has one or more fluid passageways that communicate with the hot and cold water end of the device, thereby providing for a flow path from the hot water connection to the cold water connection. The said dual purpose poppet has a cylindrical shape, and slides within the internal circular chamber to make contact with the cold water end of the housing, or to make contact with the hot water end of the housing in response to the direction of flow through the device.

Abstract: A pressure regulated diverting system (10) for water conservation includes a vacuum flow device (12), a diversion line (14), a regulating valve (16), and a containment device (18). The vacuum flow device (12) is inserted in line with the main hot water supply line (20) with a third opening connected to the diversion line (14) which passes through regulating valve (16) and is connected to containment device (18). When regulating valve (16) is open, the cooled hot water slug contained in the hot water supply line (20) fills containment device (18). Once full, the diversion line (14) and the hot water supply lines (20) are pressure equalized and, with the cold water slug, that is normally wasted, removed, hot water is available at the faucet (58) or shower head (60) essentially immediately. A smaller version for use within a shower, in particular, is available and utilizes a manually operable regulating valve (16) to force the first cold slug of cooled hot water into containment device (18).

Abstract: An on demand, multi-faceted, programmable, electronically and electromechanically controlled, water and energy conservation system, easily segmented and adaptable to the limitations of varying structures, specific conservation goals and each user's economic considerations. The energy saver segment and one of several water saver segments may be combined into a complete system, configurational to differing conditions and useable with any pressurized water supply. The invention may also be configured for installation in existing, new or add-on structures. Preselected opening and closing of remotely actuated valves alters conduit paths, to avoid water waste down the drain, waiting for hot water. Hot water delivered from the hot water supply is completely used, eliminating the energy waste of hot water cooling in the pipes.

Abstract: A hot water re-circulating system (10) in a building (12) comprising a water pump (36) connected between an auxiliary water return line (28) extending from a hot water faucet (22) to a remote hot water heater (14). The water pump (36) is controlled by a timer/switch (42) located at the hot water faucet (22), so that when the hot water faucet (22) is opened, hot water will come out therefrom. In a second embodiment, two water pumps (82) and (92) are each connected between two auxiliary water return lines (68) and (70) extending from two hot water faucets (58) and (62) to a remote hot water heater (50). Each water pump (82) and (92) is controlled by a timer/switch (88) and (98) located at the hot water faucets (58) and (62), so that when the hot water faucets (58) and (62) are opened, hot water wall come out therefrom.

Abstract: A hot water plumbing system comprising a water heater, a delivery location, a delivery line delivering water from said heater to said delivery location, a riser located adjacent said delivery location and extending upward above the level of said heater, and a return line connected adjacent the upper end of said riser and inclined so as to extend gradually downward to an input located adjacent the bottom of said heater to provide a continuous flow of hot water within the system, which ensures immediate and constant delivery of hot water to the delivery location and prevents accumulation of sediment within the system and, hence, minimizes installation and maintenance costs and significantly reduces the amount of wasted water. The system particularly employs a vacuum accelerator, which can be used to increase system vacuum and which causes rapid start-up or priming of the system.

Abstract: A dual mode water circulation apparatus for installation in a water supply line in a building upstream of a water heater provides continuously heated water at one or more remote hot water faucets. The apparatus is connected in a water return loop that includes a portion of the water supply line that is downstream of the apparatus, the water heater, the common hot water pipe, and a return line from a remote faucet. The apparatus includes a housing having a first inlet for connection to the water return line, an outlet for connection to that portion of the water supply line that connects to the water heater, and a second inlet for connection to the water supply line. There is a chamber in the housing with the inlets and outlet connecting to the chamber. There is a check valve between the first inlet and the chamber preventing flow from the apparatus outwardly from the first inlet.

Abstract: A thermal check valve for use in a gravity flow hot water recirculating system. The hot water system has a hot water heating tank, a water faucet, manifold piping from the hot water heating tank to the faucet, return piping from the faucet to the hot water heating tank, and a thermal check valve interposed in the return piping and adjacent a return inlet into the tank. The check valve has a valve body, an inlet chamber formed within the valve body, an inlet port in communication with the inlet chamber, an outlet chamber formed within the valve body, and an outlet port in communication with the outlet chamber, the outlet port being below the inlet port.

Abstract: Cold water subrogates hot water supplied to a leaky hot water faucet. An individual kitchen or bathroom faucet set incorporates the anti-dribble control feature to substitute cold water trickle for wasteful hot water trickle through the leaky hot water faucet. When the leaky faucet is turned "off" the supply of hot water feeding the faucet is stopped and a limited flow of cold water replaces the hot water supply to an extent necessary to feed the leaking trickle of water. In effect, usual hot water dribble which may leak through a faulty faucet is eloquently displaced by a sacrifice of cold water.

Abstract: A water saving device for use with domestic hot water systems of the noncirculating storage tank heater type uses a hydraulic motor to drive a water pump to pump water from the hot water pipe to a cold water pipe. Pumping begins when a hot water tap connected to the device is turned on and the water in the hot water pipe is cold. Pumping continues until a temperature sensing element senses that hot water has reached the water saving device and actuates a valve. When hot water is present at the device, the valve permits the hot water to pass directly to the tap instead of driving the hydraulic motor.

Abstract: Plumbing apparatus is provided for reducing energy consumption of a hot water heater, the apparatus includes a tank and a buoyant piston movably disposed within the tank and having a perimeter slidably engaging an inside wall of the tank. Water entering a top of the tank pushes the buoyant piston towards a bottom of the tank and at a selected position, grooves are provide in an inside wall of the tank to enable entering water to pass the buoyant piston. When the apparatus is connected between a conventional hot water heater and a cold water source, the water heater is buffered from the cold water source for small draws of water from the hot water heater thus preventing such small draws of water from tripping the water heater thermostat.

Abstract: Plumbing apparatus is provided for reducing energy consumption and controlling increases in water pressure of a hot water heater. The apparatus includes a tank and a buoyant piston movably disposed within the tank and having a perimeter slidably engaging an inside wall of the tank. Water entering a top of the tank pushes the buoyant piston towards a bottom of the tank and at a selected position, grooves are provide in an inside wall of the tank to enable entering water to pass the buoyant piston. When the apparatus is connected between a conventional hot water heater and a cold water source, the water heater is buffered from the cold water source for small draws of water from the hot water heater thus preventing such small draws of water from tripping the water heater thermostat. The buoyant piston is designed to enable expansion of tank capacity such that upon increases in water volume due to thermal expansion, pressure within the tank is controlled and rupture of the tank is prevented.

Abstract: A temperature controlled water recirculation system includes an adjustment valve for adjusting the quantities of water received from hot and cold water lines are fed to a shower nozzle. A controller, such as a temperature sensor, a timer, fluid flow meter, or the like is used for establishing the point at which a diverting valve diverts water from a recirculating return line to a shower nozzle. The return valve, therefore, determines at point in time recirculation ceases and dispensing of the water commences. In this way, water is conserved by recirculation of mixed water which cannot be used because its temperature is below or above a pre-selected threshold temperature.

Abstract: A latch assembly for mounting in a bore extending in from a side edge of a door has a backset adjustment for different distances between rotational axis of a handle or keylock and the side edge of the door. The bolt has a concentric aperture into which a bolt adjuster slidably mates with a close tolerance to prevent lateral movement between the bolt and the bolt adjuster. The latch assembly comprises a casing assembly having a bolt assembly longitudinally reciprocal therein between a retracted position and an extended position, the bolt assembly including a bolt with a cylindrical aperture therein, the bolt rotatable and reciprocal relative to a non-rotational cylindrical bolt adjuster and having a sliding fit thereon. A helical groove in one of the bolt or the bolt adjuster engages with a projection of the other of the bolt or bolt adjuster.

Abstract: Domestic water conservation piping system has thermostatically controlled diverter valve in series with water heater and shower head and/or a hot water shunt tube extending from the hot water heater to the fixture hot water supply in parallel with the thermostat piping. When low temperature water is detected in the "hot water" line, the thermostatically controlled diverter valve diverts the low temperature water to a secondary water closet which stores the water at atmospheric pressure. The secondary water closet provides make-up water to a toilet's primary water closet.

Abstract: A water circulation apparatus to provide instant hot water to faucets remote from the heater in residential and small commercial buildings when water is periodically used in the building. The apparatus comprises a body containing an aspirator and a check valve, and provisions for installation in the water supply line to the heater and cold water faucets. It uses a small water return line from a tee installed in the hot water pipe near the remote faucet, to a connector on the water circulation unit, thereby establishing a circulation loop from the water heater, through the hot water pipe, the tee and return line, and through the water circulation unit back to the heater. The aspirator is a tapered bore in the body with a concentric nozzle positioned in the large end, and a low pressure tap located in the vicinity of the nozzle outlet. The check valve uses a neutrally buoyant poppet to minimize friction.

Abstract: The present invention is a water conservation system that provides instant hot water at a user's sink. The system includes a backflow line positioned between the cold water line and a thermal switch. A check valve is placed in the backflow line to prevent hot water from entering the cold water supply. A thermal switch that contacts the flow of water is used to give a more accurate measurement of the hot water temperature. This system prevents large quantities of warm water from being pumped into the cold water supply.

Abstract: A two piece throttling valve is disclosed. The valve assembly includes a stationary outer housing with an inner removable operable assembly. In this configuration the piping (pump stack) does not have to disassembled to remove, clean or replace the internal valve pieces or the in-line screen. The inner assembly can be quickly removed for cleaning. The entire valve assembly is heated to reduce deposition of volatile process byproducts on the internal valve surfaces and reduce the cleaning frequency. A wedge plate is provided in the outer stationary valve housing to mate with a sloped bottom surface of the inner valve housing such that when the inner assembly is in position in the outer valve housing there is a tight fit between adjacent sealing surfaces around the valve bore. A single flat surface seal provides vacuum sealing between the inner assembly and outer housing. A dual valve stem (shaft) seal seals the valve shaft.

Abstract: A water conservation system including a thermostatically controlled valve means effectively diverts water from the hot water tank to a storage tank until the temperature or the water therefrom reaches a predetermined temperature. The stored water is then caused to be mixed with the water directed to the cold water conduit initially be pressure in the storage tank and subsequently by siphon action.

Abstract: A hot water appliance is provided with an accelerated delivery system which includes a pump interconnected between hot and cold water fittings and a control system for causing the pump to circulate water from the hot water fitting into the cold water fitting when the hot water appliance is turned on. Temperature sensor is provided for causing the control system to stop the pump to prevent heated water from being circulated into the cold water fitting. In addition, a hot water demand system may incorporate a sound sensor detecting water flow in a hot water delivery line and a sound-generating element may be provided for providing a characteristic sound in response to water flow in the hot water delivery line.

Abstract: An on demand, remotely activated, electronically and electro-mechanically controlled, energy saving, water conservation, hot, water recovery system, which may be installed in residential and commercial structures having a pressurized water supply (11). The system is comprised of a dual chamber, dual hot water outlet, water heating reservoir (23), and a flow control and recovery apparatus (10), in fluid communication with a cold water supply (11) and hot water outlets (93-97). The system installs in new or existing structures, without alteration of the plumbing lines or electrical wiring. The flow control (84) is preprogrammed to, upon command, drain standing water from the hot water outlets (93-97), and refill the outlets with hot water from the small chamber (23b) of the water heating reservoir (23), making hot water available at the instant an outlet is opened.

Abstract: A water conservation system including a thermostatically controlled valve means effectively diverts water from the hot water tank to a storage tank until the temperature or the water therefrom reaches a predetermined temperature. The stored water is then caused to be mixed with the water directed to the cold water conduit initially be pressure in the storage tank and subsequently by siphon action.

Abstract: A dual mode water circulation apparatus to provide instantaneous hot water to faucets remote from the heater in residential or small commercial building water systems. The apparatus comprises a cold water heat exchanger, a high sensitivity check valve, and an aspirator incorporated into a single unit.The heat exchanger is a chamber installed in the cold water supply line, containing a cooling tube exposed to the water. The check valve has a neutral buoyancy poppet and closes against an angular seat. The aspirator has a reduced cross section nozzle inside a tapered chamber connected to the water supply pipe, with a low pressure tap in the chamber bore.The apparatus is installed at an angle to the horizontal. The cooling tube is connected to a water return line from a tee in the hot water pipe at the remote faucet. The water circulation loop is from the remote hot water faucet to the heat exchanger portion of the apparatus, to the check valve, then to the aspirator and into the cold water supply to the heater.

Abstract: An instantaneous hot water device comprises a gate valve means connected to a hot water line and having a gate valve and a gate valve seat providing a controlled flow of hot water from the hot water line into a ball valve means having a ball check and a first ball valve seat having slot cooperating with the ball check to provide a small, controlled flow of hot water into a cold water line and a second ball valve seat cooperating with the ball check to prevent flow of cold water into the gate valve means and the hot water line.

Abstract: A hot water recovery system includes a hot water source; a hot water delivery line connected between said hot water source and at least one plumbing fixture along with a cold water delivery line connection between said plumbing fixture, a cold water source and said hot water source; a pump, interconnected between said hot and cold water delivery lines, enables circulation of water from the hot water delivery line through the cold water delivery line and into the hot water source, thus eliminating the need for a separate recirculation system. A control system causes the pump to circulate water from the hot water line into the cold water line and back to the hot water source when a hot water valve on said plumbing fixture is turned on; and a temperature sensor stops the pump, via the control system, to prevent heated water from being circulated through the cold water delivery lines.

Abstract: A water saving recirculating system (10) for a conventional water supply system (100) wherein: a fluid coupling (14) and solenoid valve (15) are disposed intermediate the hot water feed line (106) and a first cold water feed line (102); a one way check valve (11) is disposed in the cold water supply line (101); and, a pump (13) disposed in the first cold water feed line (102) for reversing the fluid flow through the first cold water feed line (102); wherein, the flow of water through the hot water feed line (106) is diverted through the first cold water feed line (102) until such time as the temperature of the water flowing through the hot water line (106) reaches a predetermined valve.

Abstract: Recirculation hot water system including a fluid delivery system used to supply potable water throughout a home or other facility, having a hot water supply pipe, a cold water supply/return pipe, a hot water heater, a pump, a manifold, a control system, a hot water and cold water faucet or valve, and a demand site (typically a sink or wash basin). The manifold further includes a thermostatic actuator and a check valve. The control means further includes a sending unit, installed in close proximity to the demand site, and a receiving unit, installed in close proximity to the heater. Command signals are transferred, from the sending unit to the receiving unit, via modulated signals that pass through the AC power lines that are used to distribute power throughout the home or facility.

Abstract: In a domestic hot water supply system including at least one user terminal such as a shower head to which blended hot and cold water are supplied at a selected temperature, the cold water of the blend is supplied via a check valve which responds to changes in hydrodynamic pressure so as to regulate the volumetric flow of cold water and thereby compensate for changes of water demand in other parts of the system.

Abstract: A valve body with a hollow interior chamber. Hot liquid and cold liquid conduits provide for transporting hot liquid and cold liquid from a hot liquid source and a cold liquid source to the hollow chamber. The valve body has a pair of passages joining the hollow chamber to the hot liquid and cold liquid conduits. The passage joining the hot liquid conduit to the chamber has a flow valve therein and the passage joining the hollow chamber to the cold liquid conduit has a check valve therein. The valve body is mounted at a level higher than the hot liquid source.

Abstract: A purge line to return cooled water in a hot water line directly to a cold water line to avoid wasting water by draining the cooled water while awaiting arrival of hot water at a hot water outlet valve. The purge line is connected in near adjacency to a hot water outlet valve to minimize the amount of cooled water still in the hot water line between the purge line and the valve.

Abstract: A demand recovery hot water system in accordance with the present invention provides for return of hot water from a plurality of plumbing fixtures to a hot water source. A transfer tank is provided with a movable piston which enables circulation of hot water without significant loss thereof. Continuous circulation is not required thus reducing operating costs.

Abstract: A system for removing lead from a stagnated domestic hot and cold water system having fixtures and faucets is disclosed. Cold water pipes containing cold water are connected to the fixtures. Hot water pipes containing hot water is also connected to the fixtures. Crossover pipes fluidly connect the cold water pipes to the hot water pipes so that the cold water can enter the hot water pipes. Check valves assure that the cold water enters the hot water pipes and not visa-versa. A pump circulates the cold water and the hot water through the cold and hot water pipes when the faucets are closed so that a circulation system without the need for a third water line to create the circulation system is formed from the cold water pipes through the hot water pipes and resulting in a reverse flow loop through the hot and cold water pipes.

Abstract: Herein described is a compact and self-contained circular water conservation device which can be easily installed in conjunction with existing and non-existing plumbing systems and fixtures having a source of pressurized water, a hot water supply line, a cold water supply line, a hot water heater, and outlet fixtures coupled to the hot and cold water supply lines. The water conservation device includes essentially an elecric water pump for pumping water from the hot water supply line into a solenoid valve. The solenoid valve prevents the mixture of hot and cold water systems. The solenoid valve is coupled to the cold water line directly leading to and coupled to an outlet fixture. A thermostat temperature sensor is provided for detecting the hot water temperature at the inlet port of the pump. The water conservation device, when in operation, creates a closed loop linking the hot water line to the cold water line.

Abstract: A plumbing system in accordance with the present invention provides for accelerated hot water delivery to a plurality of plumbing fixtures from a hot water source. Flow switch means are provided to enable a pump to circulate hot water to the plumbing fixtures in response to water being withdrawn from a plumbing fixture. In addition, the hot water source may include a hot water recovery apparatus for withdrawing hot water from circulation pipes subsequent to cessation of water flow from a plumbing fixture.