Liquid heaters and vaporizers – Stand boiler – And condition responsive feature
Reexamination Certificate
2001-02-09
2001-10-16
Lu, Jiping (Department: 3749)
Liquid heaters and vaporizers
Stand boiler
And condition responsive feature
C122S014310, C137S493900, C137S539000
Reexamination Certificate
active
06302063
ABSTRACT:
The present invention is generally directed to a heat trap for preventing heat loss in a water heater and storage system, and is more specifically directed to a non-restrictive heat trap assembly which provides for pressure relief.
In a typical residential or commercial water heater system, cool water is introduced into a heated storage tank through an inlet port, and hot water is removed from the storage tank through an outlet port. The ports are connected to plumbing lines leading from a municipal water source and to various plumbing fixtures within the residence or structure.
Many devices have been proposed and developed with an aim of increasing energy efficiency and reducing energy loss associated with water heater systems. Insulating elements, for example thermally insulating jackets wrapped about a water heater tank and/or connecting hot water lines provide an inexpensive, simple means of reducing some heat loss.
Unfortunately, significant heat loss can still occur, despite careful insulation of the water heater tank and pipes. This is because a significant amount of heat loss is attributable to thermal convection currents within the pipes themselves, for example at the tank inlet and outlet ports. These convention currents do not refer to the conduction of water into and/or out of the tank, but rather to heat transfer from hot water in the tank into cooler water at the ports. Thus, even when the water system is in a standby mode (i.e. water is not being introduced to or removed from the tank) a significant amount of heat loss will continuously occur despite the use of external insulation means.
Various heat traps have been proposed as a means of isolating the hot water in the tank from standing water in the connecting pipes during periods of standby. One such assembly is described in U.S. Pat. No. 4,286,573 to Nickel, issued on Sep. 1, 1981 and entitled “Water Heater Heat Trap Assembly”, and incorporated herein in its entirety by this specific reference. The Nickel patent discloses a heat trap assembly having a sealing member located against a valve seat within the piping of the cold water inlet, and a second sealing member located against a valve seat within the piping of the hot water outlet. The sealing members may be plastic or metal balls sized to seal the inlet and outlet valves. The sealing ball in the inlet piping is a low density ball that will float in water. The sealing ball in the outlet piping is a higher density ball that will sink in water.
Heat trap assemblies similar to the assembly disclosed by Nickel have been commercially available for a number of years. Unfortunately, however, sales of these generally ineffective devices have not been highly successful. Consumers have complained that the plumbing lines had become disturbingly noisy after installation of a heat trap assembly in the plumbing lines. Even small movements of the sealing ball within the piping can be audible, and are frequently heard as a tapping or rattling sound throughout the home. Thus, many consumers have had the heat trap assemblies removed after installation. In addition, available heat trap assemblies are made of galvanized steel, and conduct heat rather than provide insulation.
U.S. Pat. No. 4,964,394, issued on Oct. 23, 1990 to Threatt discloses a Water Heater with Heat Trap in Dip Tube. In general, the Threatt invention utilizes a heat trap in which the travel stroke of the sealing ball is located within a tube that extends into the storage tank itself. Threatt states that by locating the travel stroke of the ball entirely within the storage tank, noise caused by movement of the ball is reduced when compared to prior systems.
A reduction in water pressure is another drawback that has been associated with the installation of conventional heat trap assemblies. When hot water is demanded at a remote fixture, the sealing element is pushed off of the valve seat, allowing water to flow around the element and through the outlet port. However, the sealing element may act as a restriction within the water flow path, thereby decreasing water pressure at the fixture. Similarly, the sealing element within the inlet port acts as a restriction that may slow down tank replenishment.
Another important consideration is the need to provide pressure relief to the hot water tank. As is well known, water expands slightly when heated and when contained in a sealed tank, increases the water pressure within the tank. Hence, for safety purposes it is important to provide for temporary pressure relief. This pressure relief is distinct from pressure relief due to extreme pressure buildup within the tank due to malfunction. Such extreme pressure relief is typically provided in a water heater tank by a relief valve for enabling efflux exterior to the tank.
The present invention provides an improved heat trap assembly which addresses these problems, and other problems associated with the use of conventional heat trap assemblies which will later become apparent. As will be discussed in detail hereinafter, the present heat trap assembly is designed to provide quiet, safe and efficient heat trap assembly which can be easily installed in a commercial or residential facility to reduce energy consumption of a water heater tank while at the same time functioning a pressure relief element.
SUMMARY OF THE INVENTION
A heat trap assembly in accordance with the present invention, generally includes a housing adapted for interconnection between a water heater tank and a water line with the housing including an interior flow chamber which is in fluid communication with the water heater tank and the water line.
A one-way valve is disposed in the chamber for enabling unrestricted water flow only in one direction, that through the chamber. The valve generally includes a valve seat fixed within the chamber along the one direction and movable in an opposite direction along with a moveable sealing member.
A spring is disposed within the chamber for urging the sealing member against the valve seat to prevent flow through the chamber in an opposite direction. Water flow in the one direction, compresses the spring and dislodges the sealing member from the valve seat.
A pressure relief disk is provided and disposed between the valve seat and an end of the chamber. The pressure relief disk compresses under a selected water pressure exerted in the opposite direction for enabling water flow in the opposite direction at pressures greater than the selected water pressure.
In this manner, the valve isolates hot water in the water heater tank from standing water within the water line. Thus, migration of cold water into the tank and hot water out of the tank, is prevented during periods of time when water is not drawn from the hot water tank.
More particularly, the valve seat includes a notched perimeter for enabling water flow therepast upon compression of the pressure relief disk. The pressure relief disk also includes a notched perimeter for enabling water flow therepast upon compression of the pressure relief disk.
The pressure relief disk includes at least one compressible element disposed on one side of the pressure relief disk and preferably a plurality of compressible elements are provided in the form of spaced apart radial ribs.
The chamber has a cross-sectional area available for water flow greater than the cross-sectional flow of the water line, and accordingly, the heat trap assembly and valve do not provide any restriction to water flow in the one direction.
To further isolate the water line from by way of electrolysis, the housing is preferably formed from a non-metallic material.
REFERENCES:
patent: 4286573 (1981-09-01), Nickel
patent: 4964394 (1990-10-01), Threatt
patent: 5277171 (1994-01-01), Lannes
patent: 5577491 (1996-11-01), Lewis
patent: 5671771 (1997-09-01), Brandel
Hackler Walter A.
Lu Jiping
LandOfFree
Water heater heat trap with pressure relief assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water heater heat trap with pressure relief assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water heater heat trap with pressure relief assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2585421