HEAT TRAP INSERT FOR DIP TUBE

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional Patent Application Ser. No. 63/692,607, filed Sep. 9, 2024, the disclosure of which is expressly incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The present application relates generally to a dip tube assembly for use with a water heater. More particularly, the present application relates to a dip tube assembly including a dip tube and a heat trap insert.

It is known to provide a dip tube in a water heater to supply cold water to a tank. The cold water is injected at the bottom of the tank through the dip tube. The cold water is then heated where it rises in the water heater and is drawn off by a hot water discharge pipe. A pipe nipple may connect to the water heater, the water heater being made from steel, and allows plumbing for the cold water inlet to be connected to the water heater. A conventional pipe nipple is threaded on both ends and is typically made of brass, galvanized steel, or galvanized steel with a dielectric insert.

Although the exterior of galvanized nipples are dielectrically compatible with the steel water heater, the interior of the galvanized nipple is not. With the interior unprotected, the galvanized nipple may corrode, clog, rust and/or eventually leak. Brass nipples, on the other hand internally will not corrode like galvanized nipples, but the introduction of brass to the steel water heater is not a dielectrically correct connection. Left unprotected, the area of the steel water heater below the brass nipple may corrode. Therefore, a dielectric connection is desired because it prevents electrolysis with the connecting plumbing and the steel water heater.

To combat the corrosion issue and provide a dielectric connection, water heater manufacturers may supply plastic lined galvanized nipples with new water heaters. This plastic liner in the galvanized nipple is also known as the dielectric liner. These plastic lined galvanized nipples are sometimes referred to as dielectric nipples. The dielectric nipples and the brass nipples cost more than the galvanized steel nipples.

It is also known to use heat traps to minimize convective heat loss in water heaters. Heat traps are used to minimize the flow of heat from the heated water in the tank through the cold water inlet and hot water outlet openings and to the piping connected thereto. Various convective heat trap devices have been previously proposed for connection to a water heater tank at or near an inlet or outlet opening. These heat trap devices are basically check valve type structures which freely permit water to flow through the tank inlet and outlet in operational directions during water supply periods, but substantially inhibit convective water outflow through the inlet and outlet during non-demand storage periods of the water heater.

As noted above, a conventional pipe nipple is threaded on both ends, where one threaded end connects to the water heater via a coupling and the other threaded end connects to the plumbing. The dip tube is often located below the threaded end of the pipe nipple that connects to the water heater. The dip tube typically rests within the coupling but requires a gasket and a dip tube cup to retain the dip tube therein. The dip tube, the dielectric liner, the gasket, the heat trap and the dip tube cup are often separate components that must be assembled or disassembled during installation and/or service of the water heater. This results in increased amounts of labor for verification of both the proper assembly and efficient functionality of each separate component. This increased labor results in increased costs for the manufacturer and installer which are typically passed on to the consumer. Moreover, improper installation of these separate components may result in leaks, which may form between the dip tube, the heat trap, and the pipe nipple.

Conventional dip tubes may include an opening within the tube side wall below the pipe nipple that pushes cold water out into the hot water near the top of the tank, thereby adversely impacting the efficiency of the water heater.

As a result of the above, there is a need to reduce the labor and costs associated with the assembly and repair of dip tubes and heat traps and to improve sealing of assemblies and connections to pipe nipples. Additionally, there is a desire for improved dip tubes and heat traps to prevent cold water from flowing through the upper end of the dip tube into hot water of the tank.

According to an illustrative embodiment of the present disclosure, a dip tube assembly for use with a water heater includes a dip tube and a heat trap insert. The dip tube includes a first tubular body having a first side wall extending along a longitudinal axis between an upper end and a lower end. A retainer opening is positioned within the first side wall. An anti-siphon opening is positioned within the first side wall and in axial spaced relation to the retainer opening. The heat trap insert includes a second tubular body having a second side wall extending along the longitudinal axis between the upper end and the lower end. The second side wall is supported within the first side wall of the dip tube and defines a water passageway. A retainer peg extends outwardly from the second side wall and is received within the retainer opening of the first side wall. A heat trap is supported by the second side wall and extends within the water passageway. The lower end of the second side wall is positioned axially below the anti-siphon opening of the first side wall.

According to another illustrative embodiment of the present disclosure, a dip tube assembly for use with a water heater includes a dip tube and a heat trap insert. The dip tube includes a first tubular body having a first side wall extending along a longitudinal axis between an upper end and a lower end. An anti-siphon opening is positioned within the first side wall and in axial spaced relation to the retainer opening. The heat trap insert includes a second tubular body having a second side wall extending along the longitudinal axis between the upper end and the lower end. The second side wall is supported within the first side wall of the dip tube and defines a water passageway. A heat trap is supported by the second side wall and extends within the water passageway. The lower end of the second side wall is positioned axially below the anti-siphon opening of the first side wall. A gap is defined between the inner surface of the first side wall and the outer surface of the second side wall, such that a Venturi effect is configured to be defined proximate the lower end of the second tubular body and low pressure draws water radially inwardly through the anti-siphon opening.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more detailed descriptions of particular embodiments of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the drawings particularly refers to the accompanying figures, in which:

FIG. 1 is a partial cross-sectional view of a water heater according to the prior art;

FIG. 2 is a cross-sectional view of a dip tube connected to a nipple of a water heater according to the prior art;

FIG. 3 is a perspective view of a heat trap insert received within a dip tube according to an illustrative embodiment of the disclosure;

FIG. 4 is an exploded perspective view of the heat trap insert in spaced relation to the dip tube according to an illustrative embodiment of the disclosure;

FIG. 5 is a first exploded side elevational view of the heat trap insert in spaced relation to the dip tube according to an illustrative embodiment of the disclosure;

FIG. 6 is a second exploded side elevational view of the heat trap insert in spaced relation to the dip tube of FIG. 5, showing the heat traps in spaced relation to the insert body;

FIG. 7 is a first longitudinal cross-sectional view of the heat trap insert and the dip tube of FIG. 3; and

FIG. 8 is a second longitudinal cross-sectional view of the heat trap insert and the dip tube of FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

The embodiments hereinafter disclosed are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following description. Rather the embodiments are chosen and described so that others skilled in the art may utilize its teachings.

FIGS. 1 and 2 illustrate a conventional water heater 2 including a tank 4 containing water, a jacket 6 surrounding the tank 4, and a heat source or burner 8. A dip tube 10 is connected to a nipple 12 of a water heater according to the prior art. The nipple 12 includes upper threads 14 and lower threads 16 on each end of the nipple 12. A dielectric liner 18 is located on the inner surface of the nipple 12. The upper threads 14 connect to plumbing, for example a cold water inlet pipe 15, while the lower threads 16 connect to a coupling 20 of the water heater 2. A dip tube cup or retaining cup 22 is located near the bottom of the coupling 20. A gasket 24 is located below the nipple 12 and around an upper portion of the dip tube 10 and rests upon the dip tube cup to retain the dip tube 10 in position. Separate heat trap assemblies 26 are respectively installed within the nipple 12 near the upper threads 14 and the lower threads 16.

The dip tube 10 illustratively includes a tubular body 28 having an upper end fluidly coupled to the nipple 12. The dip tube 10 may further include a dispersion tip 30 at the bottom of the tubular body 28 to disperse the incoming water into the water heater 2. The burner 8 is positioned within a combustion chamber 32 which is in communication with a flue tube 34 to vent gasses therefrom.

Additional details of a pipe nipple insert and dip tube for a conventional water heater are disclosed in U.S. Pat. No. 12,084,261 to Currey et al., the disclosure of which is expressly incorporated herein by reference.

With reference now to FIGS. 3 and 4, a dip tube assembly 100 according to an illustrative embodiment of the present disclosure includes a dip tube 110 and a heat trap insert 112. The dip tube 110 illustratively includes a first tubular body 113 having a first side wall 114 extending along a longitudinal axis 116 between an upper end 118 and a lower end 120. The first side wall 114 includes an inner surface 122 and an outer surface 124 (FIGS. 7 and 8).

With reference to FIGS. 5 and 6, a pair of diametrically opposed retainer openings 126a, 126b are illustratively formed within the first side wall 114 of the dip tube 110. An anti-siphon opening 128 is positioned within the first side wall 114 and is positioned in axial spaced relation to the retainer openings 126. The first side wall 114 of the dip tube 110 may be formed of a conventional material, such as steel.

With reference to FIGS. 7 and 8, the heat trap insert 112 includes a second tubular body 130 having a second side wall 132 extending along the longitudinal axis 116 between an upper end 134 and a lower end 136. The second side wall 132 includes an inner surface 138 and an outer surface 140. The second side wall 132 is supported within the first side wall 114 of the dip tube 110 and defines a water passageway 142.

A pair of diametrically opposed retainer pegs 144a, 144b extend radially outwardly from the second side wall 132 of the heat trap insert 112. Each retainer peg 144a, 144b includes a leading inclined edge 146, and a trailing retaining edge 148 for locking the retainer peg 144a, 144b into respective retainer opening 126a, 126b of the dip tube 110.

A first or upper heat trap 150a and a second or lower heat trap 150b are supported by the second side wall 132 and extend within the water passageway 142. A flare or flange 152 extends radially outwardly from the upper end 134 of the second side wall 132. The flange 152 is configured to engage the upper end 118 of the dip tube 110, thereby preventing the heat trap insert 112 from passing downwardly through the dip tube 110.

Each heat trap 150a, 150b includes an outer holder 154 and an inner flap 156. The outer holder 154 is supported within a slot 155 formed within the second side wall 132 of the heat trap insert 112, while the inner flap 156 extends inwardly from the outer holder 154 into the water passageway 142. The inner flap 156 may be molded from an elastomer. The lower heat trap 150b is illustratively positioned axially below the upper heat trap 150a. The heat traps 150a and 150b are illustratively diametrically opposed.

With reference to FIG. 8, the lower end 136 of the heat trap insert 112 is positioned axially below the anti-siphon opening 128 of the dip tube 110. A gap 158 is defined between the inner surface 122 of the first side wall 114 and the outer surface 140 of the second side wall 132 defining a passageway 160. As such, a Venturi effect (shown at 162) is configured to be defined proximate the lower end of the second tubular body and low pressure draws water radially inwardly through the anti-siphon opening 128. More particularly, cold water (represented by arrows 164 in FIG. 8) does not flow through the anti-siphon opening 128. Low pressure from the Venturi effect 162 instead draws hot water radially inwardly from the tank 4 into the dip tube 110 (represented by arrow 166 in FIG. 8).

A plurality of ribs 168 (FIG. 4) extend radially outwardly from the outer surface 140 of the heat trap insert 112 and are configured to frictionally engage the inner surface 122 of the dip tube 110. The heat trap insert 112 may be formed of a molded polymer.

In one illustrative embodiment, the heat trap insert 112 is made from high density polyethylene that is crosslinked (PEX). PEX contains crosslinked bonds in the polymer structure changing the thermoplastic into a thermoset. Crosslinking may be accomplished during or after the molding of the part. The required degree of crosslinking for crosslinked polyethylene tubing, according to ASTM Standard F 876-93 is between 65-89%. There are three classifications of PEX, referred to as PEX-A, PEX-B, and PEX-C. PEX-A is made by the peroxide (Engel) method. In this method, peroxides blended with the polymer performs crosslinking above the crystal melting temperature. The polymer is typically kept at an elevated temperature and pressure for long periods of time during the extrusion process to form PEX-A. PEX-B is formed by the silane method, also referred to as the “moisture cure” method. In this method, silane compounds blended with the polymer induces crosslinking during molding and during secondary post-extrusion processes, producing cross-links between a crosslinking agent. The process is accelerated with heat and moisture. The crosslinked bonds are formed through silanol condensation between two grafted vinyltrimethoxysilane units. PEX-C is produced by application of radiation, such as by an electron beam using high energy electrons to split the carbon-hydrogen bonds and facilitate crosslinking.

Illustratively, the heat trap insert 112 may be polyethylene or crosslinked polyethylene (PEX) as discussed above, but may also be made from various other polymers as desired for the application. In the practice of this invention, illustrative and non-limiting examples of the polymers that may be used in various combinations to form the pipe nipple insert 100, 200 include: polyacetals, nylons or polyamides, including various types of nylon-6, nylon-6/6, nylon-6/9, nylon-6/10, nylon-6/12, nylon-11, nylon-12, acrylonitrile butadiene styrene terpolymers, polystyrenes, polycarbonates, polyvinyl chlorides and chlorinated polyvinyl chlorides, polyethylene terephthalate polyester, polyethylene homopolymers and copolymers, including all molecular weight and density ranges and degrees of crosslinking, polypropylene homopolymers and copolymers, polybutene resins, poly(meth)acrylics, polyalkylene terephthalates, polyetherimides, polyimides, polyamide-imides, polyacrylates of aromatic polyesters, polyarylether ketones, polyacrylonitrile resins, polyphenylene oxides including polystyrene miscible blends, polyphenylene sulfides, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, styrene maleic anhydride copolymers, polyarylsulfones, polyethersulfones, polysulfones, ethylene acid copolymers, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, thermoplastic elastomers covering a hardness range of from 30 Shore A to 75 Shore D, including styrenic block copolymers, polyolefin blends (TPO), elastomeric alloys, thermoplastic polyurethanes (TPU), thermoplastic copolyesters, and thermoplastic polyamides, polyvinylidene chlorides, allyl thermosets, bismaleimides, epoxy resins, phenolic resins, unsaturated thermoset polyesters, thermoset polyimides, thermoset polyurethanes, and urea and melamine formaldehyde resins. Other polymeric materials may be selected as suitable for a desired application.

In one illustrative embodiment, the polymers for the heat trap insert 112 may be high density polyethylene, which is subsequently crosslinked, preferably by the application of an electron beam, although other modes of crosslinking are envisioned to be within the scope of this invention. In another illustrative embodiment, the polymers for the heat trap insert 112 may be glass-filled high density polyethylene, which is subsequently crosslinked by application of an electron beam.

The illustrative dip tube assembly 100 of the present disclosure does not require that it is fit on the top of the water heater, which could allow for shorter pipe nipples to make top connections. Additionally, the dip tube assembly 100 could allow for automated assembly of the heat traps 150a, 150b into the heat trap insert 112.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only example embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected by the appended claims and the equivalents thereof.