US20110247572A1

US20110247572A1 - Water heater including a dip tube

Info

Publication number: US20110247572A1
Application number: US13/081,676
Authority: US
Inventors: Timothy Mitchell Smith; J. Eric Arnold; Ramin K. Rahmani; Mark Allan Murphy
Original assignee: AO Smith Corp
Current assignee: AO Smith Corp
Priority date: 2010-04-09
Filing date: 2011-04-07
Publication date: 2011-10-13

Abstract

A water heater includes a storage tank, a heat source for heating water stored in the storage tank, and a dip tube extending into the tank. The dip tube includes upper and lower ends, a restriction between the upper and lower ends so as to create back pressure in the dip tube above the restriction, the restriction positioned in an upper portion of the storage tank, a lower opening below the restriction for providing cold water to a lower portion of the storage tank, and an upper opening above the restriction for providing cold water to the upper portion of the storage tank due to the first restriction.

Description

RELATED APPLICATIONS

This application claims priority to co-pending U.S. Provisional Patent Application No. 61/322,387 filed on Apr. 9, 2010, the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to water heaters. More specifically, the present invention relates to dip tubes for water heaters. A dip tube is used to provide cold water to the storage tank of the water heater.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a water heater including a storage tank, a heat source for heating water stored in the storage tank, and a dip tube extending into the tank. The dip tube includes upper and lower ends, a restriction between the upper and lower ends so as to create back pressure in the dip tube above the restriction, the restriction positioned in an upper portion of the storage tank, a lower opening below the restriction for providing cold water to a lower portion of the storage tank, and an upper opening above the restriction for providing cold water to the upper portion of the storage tank due to the first restriction.
The present invention provides, in another aspect, a dip tube for use with a water heater including a storage tank with a lower portion and an upper portion and a heat source for heating water stored in the storage tank. The dip tube including an upper end, a lower end, a restriction between the upper and lower ends so as to create back pressure in the dip tube above the restriction, the restriction positioned in an upper portion of the storage tank, a lower opening below the restriction for providing cold water to the lower portion of the storage tank, and an upper opening above the restriction for providing cold water to the upper portion of the storage tank due to the first restriction.
Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a water heater including a dip tube.

FIG. 2 is a perspective view of the dip tube of FIG. 1.

FIG. 3 is a partial sectional view of the dip tube of FIG. 2 along line 3-3.

FIG. 4 is a perspective view of an insert of the dip tube of FIG. 1.

FIG. 5 is an exploded perspective view of a portion of the dip tube of FIG. 1.

FIG. 6 is a sectional view of a water heater including a dip tube.

FIG. 7 is a perspective view of the dip tube of FIG. 6.

FIG. 8 is a partial sectional view of the dip tube of FIG. 7 along line 8-8.

FIG. 9 is a sectional view of the dip tube of FIG. 7 along line 9-9.

FIG. 10 is a sectional view of the dip tube of FIG. 7 along line 10-10.

FIG. 11 is a sectional view of the dip tube of FIG. 7 along line 11-11.

FIG. 12 is a sectional view of a dip tube.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

FIG. 1 illustrates a water heater 100 including a tank 110 containing water, a jacket 115 surrounding the tank 110, and a heat source or burner 120. The tank includes an upper portion 125 and a lower portion 130. In the illustrated embodiment, the upper portion 125 is the upper half of the tank 110 and the lower portion 130 is the lower half of the tank 110. Insulation 135 is provided between the tank 110 and the jacket 115. A flammable fuel is provided to the burner 120 by a fuel line inlet 140 connected to a fuel valve 145. The burner 120 is positioned in a combustion chamber 150 beneath the tank 110. The fuel valve 145 is connected to a fuel supply. The fuel can be, for example, natural gas or propane. The combustion chamber 150 is connected to an air supply, for example, the atmosphere around the water heater 100. A flue tube 155 extends from the combustion chamber 150 through the tank 110. The products of combustion or exhaust gases created by the burner 120 flow through the flue tube 155 to heat the water stored in the tank 110. A cold water inlet pipe 160 is connected by a spud 165 to a dip tube 170 to supply cold water to the tank 110. A hot water supply pipe 175 connected to a spud 180 supplies hot water to an end-use location, for example, a faucet. A temperature and pressure (T&P) valve 185 permits water to be released from the tank 110 in the event of high pressure or high temperature within the tank 110. The water heater 100 as described above is a conventional gas-fired water heater. Alternatively, the water heater 100 is a conventional electric water heater and the heat source is at least one electrical heating element extending into the tank, rather than a burner 120.
FIG. 2 illustrates the dip tube 170. The dip tube is formed by a tubular wall 190 that extends from an upper end 195 to a lower end 200. The lower end 200 is positioned in the lower portion 130 of the tank 110. The dip tube 170 can have various overall lengths and diameters as is known in the art. In the illustrated construction, the dip tube 170 has a length of approximately 44 inches, an outside diameter of approximately 0.65 inch, and a wall thickness of approximately 0.035 inch.
An insert 205 is located inside the dip tube 170. The insert 205 is shown in detail in FIGS. 3-4. The insert 205 provides a restriction 210 in the dip tube 170. The restriction 210 is located in the upper portion 125 of the tank 110. Preferably, the top of the insert 205 is approximately 6.5 inches below the upper end 195 of the dip tube 170. The wall 190 has therein a hole or opening 215. The opening 215 is positioned above the restriction 210. Preferably, the opening 215 is located approximately six inches below the upper end 195 and the diameter of the opening 215 is approximately 0.31 inch. Alternatively, multiple openings located above the restriction are provided in the wall of the dip tube.
The insert 205 is preferably made of cross-linked polyethylene (PEX) and has a tubular side wall 220 defining a central passageway 225. The outside of the side wall 220 has thereon a plurality of circumferential barbs 230 that provide a friction fit with the inside of the dip tube 170. Alternatively, the insert 205 can be secured within the dip tube 170 by a variety of appropriate methods, including a threaded connection, adhesive, or a friction fit without barbs, for example. The lower end of the insert 205 includes an annular hub 235 with a central opening 240. The hub 235 is connected to the side wall 220 by a plurality of spokes 245 extending downwardly and inwardly from the lower end of the side wall 220. Water flowing through the insert 205 can exit through the openings 247 between the spokes 245 or through the hub opening 240.
The insert 205 effectively reduces the inside diameter of the dip tube 170, creating above the restriction 210 a back pressure that forces cold water out of the dip tube 170 through the opening 215. The cold water exiting through the opening 215 into the upper portion 125 of the tank 110 helps to keep the temperature in the upper portion 125 within the preferred operating temperatures, thereby avoiding triggering the T&P valve 185 due to high temperature. In this way, the dip tube 170 addresses a problem where water flows of approximately one gallon per minute (or lower) can cause overheating at the upper portion 125 of the tank 100, which would trip the T&P valve 185 due to high temperature. Additionally, the dip tube 170 inhibits stacking within the tank 110, which helps improve the Energy Factor (EF) of the water heater 100 by preventing unnecessary cycling of the heat source 120.
As shown in FIG. 5, a diffuser 250 is inserted in the lower end 200 of the dip tube 170. The diffuser is preferably made of cross-linked polyethylene (PEX) and is similar in construction to the insert 205. The diffuser 250 includes a tubular side wall 255 defining a central passageway 260. The outside of the side wall 255 has thereon a plurality of circumferential barbs 265 that provide a friction fit with the inside of the dip tube 170. Alternatively, the diffuser 250 can be secured to the dip tube 170 by a variety of appropriate methods, including a threaded connection, adhesive, or a friction fit without barbs, for example. A lower portion 270 of the side wall 260 has an increased thickness and has therein three openings 275 spaced one hundred twenty degrees apart. Alternatively, more or fewer openings 275 are formed in the lower portion 270. The lower end of the diffuser 250 includes an annular hub 280 with a central opening 285. The hub 280 is connected to the side wall 255 by a plurality of spokes 290 extending downwardly and inwardly from the lower end of the side wall 255. Cold water exits the dip tube 170 into the lower portion 130 of the tank 110 through the diffuser 250. Water exits the diffuser through the side wall openings 275, through the openings 295 between the spokes 290, or through the hub opening 285. The total area of the side wall openings 275, the hub opening 285, and the openings 295 of the diffuser 250 is greater than the total area of the hub opening 240 and the openings 247 of the insert 205. Alternatively, the dip tube 170 does not include the diffuser 250 so that cold water exits the dip tube 170 into the lower portion 130 of the tank 110 through the lower end 200 of the dip tube 170.
An alternative dip tube 370 is illustrated in FIGS. 6-11. Components similar to those of the dip tube 170 described above are numbered in a similar fashion plus two hundred.
As shown in FIGS. 7-9, a restriction 410 is formed in the dip tube 370. The restriction 410 is located in the upper portion 125 of the tank 110. The inner diameter of the dip tube 370 is reduced at the restriction 410. Three openings 415 are formed through the wall 390 and are positioned above the restriction 410. The openings 415 are uniformly distributed around the circumference of the dip tube 370. Alternatively, more or fewer openings 415 can be formed through the wall 390. The restriction 410 creates a back pressure that forces cold water out of the dip tube 370 through the openings 415 and into the tank 110. Preferably, the center points of the openings 415 are included in a plane 417 (shown in FIG. 8 and also as the cutting plane of FIG. 9) that is perpendicular to the longitudinal axis 372 of the dip tube 370. Preferably, the openings 415 are of equal diameter. Alternatively, the diameter of the openings 415 can vary.
As shown in FIGS. 7 and 10, a second restriction 510 and associated openings 515 are formed in the dip tube 370 below the restriction 410. The restriction 510 and openings 515 are similar to the restriction 410 and openings 415 described above. The openings 515 are offset from the openings 415 so that none of the openings 515 are aligned with any of the openings 415. The restriction 510 creates a back pressure that forces cold water out of the dip tube 370 through the openings 515 and into the tank 110. Preferably, the center points of the openings 515 are included in a plane (the cutting plane of FIG. 10) that is perpendicular to the longitudinal axis 372 of the dip tube 370.
As shown in FIGS. 7 and 11, a third restriction 610 and associated openings 615 are formed in the dip tube 370 below the restriction 510. The restriction 610 and openings 615 are similar to the restriction 410 and openings 415 described above. The openings 615 are offset from the openings 515 so that none of the openings 615 are aligned with any of the openings 515. The restriction 610 creates a back pressure that forces cold water out of the dip tube 370 through the openings 615 and into the tank 110. Preferably, the center points of the openings 615 are included in a plane (the cutting plane of FIG. 11) that is perpendicular to the longitudinal axis 372 of the dip tube 370.
The restrictions 410, 510, and 610 are integrally formed in the dip tube 370. Alternatively, the dip tube 370 can include more or fewer restrictions. The spacing between the restrictions can be constant or can vary. Alternatively, the restrictions 410, 510, and 610 can be created by multiple inserts 205 located in the dip tube 370. Preferably, the openings 415, 515, and 615 all have the same diameter. Alternatively, the openings 415 have a different diameter than the openings 515, which have a different diameter than the openings 615.
An alternative dip tube 670 is illustrated in FIG. 12. The dip tube 670 includes an insert 675, an upper tube 680, and a lower tube 685. The insert 675 has a tubular side wall 690 that defines a central passageway 695. The insert 675 includes an upper portion 700, a central portion 705, and a lower portion 710. The outside of the upper portion 700 has thereon a plurality of circumferential barbs 715 that provide a friction fit with the inside of the upper tube 680. The central portion 705 includes a restriction 720 so that the diameter of the central passageway 695 at the central portion 705 is smaller than the diameter of the central passageway 695 at either the upper portion 700 or the lower portion 710. The outside of the lower portion 710 has thereon a plurality of circumferential barbs 715 that provide a friction fit with the inside of the lower tube 685. Alternatively, the insert 675 can be secured to the upper tube 680 and the lower tube 685 by a variety of appropriate methods, including a threaded connection, adhesive, or a friction fit without barbs, for example.
The upper tube 680 is formed by a tubular wall 725 and includes a lower end 730. The wall 725 has therein a hole or opening 735. Alternatively, multiple openings 735 are provided in the wall 725. The lower tube 685 is formed by a tubular wall 740 and includes an upper end 745.
The dip tube 670 is constructed by inserting the upper portion 700 of the insert 675 into the lower end 730 of the upper tube 680 and by inserting the lower portion 710 of the insert 675 into the upper end 745 of the lower tube 685 so that the insert 675 connects the upper tube 680 to the lower tube 685. The central portion 705 of the insert 675 effectively reduces the inside diameter of the dip tube 670, creating above the restriction 720 a back pressure that forces cold water out of the dip tube 670 through the opening 735. A dip tube with multiple restrictions similar to the dip tube 670 can be constructed by using additional inserts 675 and additional tubes so that when the additional inserts 675 and tubes are attached to one another, a back pressure is created above the restriction 720 of each insert that 675 forces cold water out of the dip tube through an opening 735 in the tube above that insert 675.
Various features of the invention are set forth in the following claims.

Claims

1. A water heater comprising:

a storage tank;

a heat source for heating water stored in the storage tank;

a dip tube extending into the tank, the dip tube having upper and lower ends, a restriction between the upper and lower ends so as to create back pressure in the dip tube above the restriction, the restriction positioned in an upper portion of the storage tank, a lower opening below the restriction for providing cold water to a lower portion of the storage tank, and an upper opening above the restriction for providing cold water to the upper portion of the storage tank due to the restriction.

2. The water heater of claim 1, wherein the upper opening is one of a plurality of upper openings above the restriction and uniformly distributed around the circumference of the dip tube.

3. The water heater of claim 2, wherein the dip tube further includes a second restriction between the upper end and the lower end so as to create back pressure in the dip tube above the second restriction, and a plurality of second upper openings uniformly distributed around the circumference of the dip tube, the second upper openings positioned above the second restriction for providing water to the storage tank due to the second restriction.

4. The water heater of claim 3, wherein the upper openings each have a first diameter and the second upper openings each have a second diameter different than the first diameter.

5. The water heater of claim 3, wherein the dip tube further includes a longitudinal axis, and wherein center points of the first-mentioned upper openings define a first plane that is substantially perpendicular to the longitudinal axis and center points of the second upper openings define a second plane that is substantially perpendicular to the longitudinal axis.

6. The water heater of claim 5, wherein the first-mentioned upper openings each have a first diameter and the second upper openings each have a second diameter different than the first diameter.

7. The water heater of claim 5, wherein the second upper openings are offset from the first-mentioned upper openings.

8. The water heater of claim 7, wherein the first-mentioned upper openings each have a first diameter and the second upper openings each have a second diameter different than the first diameter.

9. The water heater of claim 3, wherein the dip tube further includes a third restriction between the upper end and the lower end so as to create back pressure in the dip tube above the third restriction and a plurality of third upper openings uniformly distributed around the circumference of the dip tube, the third upper openings positioned above the third restriction for providing water to the storage tank due to the third restriction.

10. The water heater of claim 9, wherein the first-mentioned upper openings each have a first diameter, the second upper openings each have a second diameter different than the first diameter, and the third upper openings each have a third diameter different than the first diameter and the second diameter.

11. The water heater of claim 9, wherein the dip tube further includes a longitudinal axis; and wherein center points of the first-mentioned upper openings define a first plane that is substantially perpendicular to the longitudinal axis, center points of the second upper openings define a second plane that is substantially perpendicular to the longitudinal axis, and center points of the third upper openings define a third plane that is substantially perpendicular to the longitudinal axis.

12. The water heater of claim 11, wherein the first-mentioned upper openings each have a first diameter, the second upper openings each have a second diameter different than the first diameter, and the third upper openings each have a third diameter different than the first diameter and the second diameter.

13. The water heater of claim 11, wherein the second upper openings are offset from the first-mentioned upper openings and the third upper openings are offset from the second upper openings.

14. The water heater of claim 1, wherein the restriction is formed as an insert that is positioned within the dip tube.

15. The water heater of claim 1, wherein the restriction is integrally formed with the dip tube.

16. The water heater of claim 1, wherein the dip tube further includes an insert, an upper tube, and a lower tube, the insert connecting the upper tube to the lower tube; wherein the restriction is formed in the insert; and wherein the upper opening is formed in the upper tube.

17. The water heater of claim 1, wherein the dip tube further includes a second restriction between the upper end and the lower end so as to create back pressure in the dip tube above the second restriction and a second upper opening above the second restriction for providing water to the storage tank due to the second restriction.

18. The water heater of claim 17, wherein the first-mentioned restriction and the second restriction are integrally formed with the dip tube.

19. The water heater of claim 17, wherein the dip tube further includes a third restriction between the upper end and the lower end so as to create back pressure in the dip tube above the third restriction, and a third upper opening above the third restriction for providing water to the storage tank due to the third restriction.

20. A dip tube for use with a water heater including a storage tank with a lower portion and an upper portion and a heat source for heating water stored in the storage tank, the dip tube comprising:

an upper end;

a lower end;

a restriction between the upper and lower ends so as to create back pressure in the dip tube above the restriction, the restriction positioned in an upper portion of the storage tank;

a lower opening below the restriction for providing cold water to the lower portion of the storage tank; and

an upper opening above the restriction for providing cold water to the upper portion of the storage tank due to the first restriction.