CA2009273C - Potable hot water storage vessel and method of manufacture - Google Patents

Abstract

A potable, hot water storage vessel is shown with a metallic body having a water inlet, water outlet and at least one additional opening communicating the vessel interior and exterior. A flexible, non-molded liner is installed within the vessel interior through the additional opening. The liner has integrally formed ports which extend through the vessel inlet and outlets to the exterior of the vessel body. A bolt-on flange is received on the vessel exterior at the inlet and outlet to form a seal with each of the liner ports.

Description

7 ~ -~

BACKGROUND OF THE INVENTION

11 2. Fielll of the rnvention.

13 The present invention relates to water storage 14 vessels of the type used for potable water supplies and, particularly, to such vessels designed for use as 16 water heaters and to methods of making the same.

18 3. Description of the Prior Art.

A variety of water heater and hot water storage 21 vessel designs are known which typically feature a 22 metallic vessel body, often formed of steel, having a 23 water inlet, a water outlet and at least one additional 24 opening. The additional opening can receive, for 25 example, a heat generating means. In order to provide 26 potable water fit for human consumption, it is 27 necessary to line the vessel body with a material which 28 resists the corrosive attack of water, including the 29 corrosive attack of water containing such common 30 corrosion agents as carbon dioxide, oxygen, chloride 31 ions, sulfate ions, and the like.

32 :~

2~3~9~3 .,..", ~

1 In the past, the lining was typically applied by 2 spraying on a plastic type material or molding in a 3 corrosion resistant material, as by using a slush type 4 molding process. United States Patent No. 3,207,358, issued September 21, 1965, to Fliss, shows a method of 6 corrosion protecting a water heater in which an inner 7 layer formed of an epoxy resin is covered with an outer 8 layer of a thermoplastic chlorinated polyether resin.
9 The manufacturing process includes multiple spray and curing steps. The commonly called "glass lined" water 11 heaters available commercially have interior surfaces 12 which are coated with a porcelain enamel type material.
13 The assignee of the present invention has, for a number 14 of years, provided water heaters having interiors covered with an electroless nickel which forms a non-16 ferrous corrosion resistant protective shield within 17 the vessel body.

19 While the prior designs accomplish their intended purpose of providing corrosion protection, they are 21 time consuming and expensive from a manufacturing 22 standpoint. Also, because the lining was sprayed or 23 molded and therefore integrally bonded to the vessel 24 interior, it was not possible to easily repair or replace a damaged or worn liner.

27 The present invention has as its object to provide 2~3 a hot water storage vessel with an improved liner 29 arrangement which resists the corrosive attack of water containing common corrosion agents to thereby ensure a 31 supply of potable water fit for human consumption.

2~X73 1 Another object of the invention is to provide a hot 2 water storage vessel having a metallic body and a 3 flexible, non-molded liner which covers substantially 4 the entire interior of the vessel body, the liner being easily installed with a minimum of effort and expense.

7 Another object of the invention is to provide such 8 a vessel having a replaceable liner which facilitates 9 repair operations so that it is not necessary to discard the vessel body in the case of a damaged or 11 defective liner.

13 Additional objects, features and advantages will be 14 apparent in the written description which follows.

- ~ Z~392~3 SUMMARY OF THE INVENTION

3 The potable, hot water storage vessel of the 4 invention includes a vessel body having a water inlet, a water outlet and at least one additional opening 6 which communicates the vessel interior and exterior. A
7 flexible, non-molded liner is installed within the 8 vessel body through the additional opening. The liner 9 has an integrally formed water inlet and water outlet ports which extend through the vessel water inlet and 11 water outlets, respectively, to the exterior of the 12 vessel body.

14 A bolt-on flange is also provided to matingly engage the inlet and outlet ports on the exterior of 16 the vessel body in order to receive a variety of 17 accessory fittings.

2 U ~ 9 ~ 7 3 BRIEF DESCRIPTION OF THE DRAWINGS

3 Figure l is a simplified, side view, partially in 4 cross-section, showing an assembled potable, hot water storage vessel of the invention having the replaceable 6 liner installed within the vessel body;

8 Figure 2 is a perspective view of the vessel body 9 of Figure 1 showing the installation of the replaceable liner;

12 Figure 3 is an isolated side, cross-sectional view 13 of one of the vessel outlets showing the liner port 14 extending therethrough;
16 Figure 4 is a view of a portion of the vessel 17 exterior showing the installation of the bolt-on 18 flange;
19 ..
Figure 5 is a cross-sectional view of the vessel 21 outlet showing the bolt-on flange installed thereon;

23 Figure 6 is a top view of the bolt-on flange of 24 Figure 5;
26 Figure 7 is a cross-sectional view taken along 27 lines VII.-VII. of Figure 6; and 29 Figure 8 is a cross-sectional view taken along lines VIII.- VIII. of Figure 6.

za9~9273 , .........

DETAILED DESCRIPTION OF THE INVENTION

3 Figure 1 shows a potable, hot water storage vessel 4 of the invention designated generally as 11. The vessel 11 includes a body 13 having tubular sidewalls 6 14, the sidewalls 14 being provided with a plurality of 7 fittings. For instance, the fittings can include a 8 cold water inlet 15 a hot water outlet 17 and a 9 pressure relief fitting 19.
11 The body 13 can be provided in a variety of 12 configurations. For instance, the body 13 can be 13 formed of a suitable metal, such as steel, having an 14 open interior 21 tubular sidewalls 23 and a pair of opposing ends 25, 27. In the embodiment shown, end 25 16 is initially open and comprises one additional opening 17 in the body 13 besides the cold water inlet 15 and hot 18 water outlet 17. In other embodiments of the invention, 19 the opposing ends 25, 27 are closed and the additional opening is provided in the tubular sidewalls 23. In the 21 embodiment shown in Figure 2, the steel body 13 can be 22 covered with heavy density fiberglass insulation which 23 is, in turn, covered by segmented steel jacket panels 24 18 to prevent heat loss.
26 The additional opening , in this case open end 25, 27 of the vessel 13 is adapted to receive a heat 28 generating means. The heat generating means can be, 29 for instance, gas, oil, or gas/oil fired or, in some embodiments, can comprise an electric resistive heating 31 element. In the embodiment shown in Figure 1, the heat 32 generating means is a forced draft heating module 29.
33 The module 29 includes a submersible portion 31 which 2C~9~3 -1 is adapted to be received within the open end 25 and 2 which includes a cylindrical elongated member having an 3 open end 33 and an opposite closed end 35. The 4 combustion chamber assembly 31 also includes a mounting 5 portion 37 for detachably engaging the vessel opening 6 25 for mounting the module 29 within the vessel. The 7 mounting portion 37 includes a ring like extent 39 8 which mounts flush against a flange portion 41 of the 9 vessel 13. The flange 41 is securely affixed to the vessel body 13 or is provided as an integral part of 11 the vessel body.

13 The combustion chamber assembly 31 also includes a 14 plurality of curved fire tubes 43 each of which has an 15 end 45 which communicates with the combustion chamber 16 31 through closed end 35 and which has an opposite end 17 47 which extends through the mounting portion 3 7. Each 18 of the curved tubes 43 is characterized in that at 19 least a portion of the length thereof is generally U-20 shaped. The combustion chamber portion 31 extends at 21 least partially the length of the curved fire tubes 43 22 creating a long leg 51 running along the exterior of 2 3 the combustion chamber and separated by the U-shaped 24 portions 49 from a short leg 53 which joins and extends 25 through the closed end 35.

27 The ends 47 of the curved tubes communicate with a 28 cylindrically shaped flue collector 55 for conducting 29 the products of combustion from the combustion chamber 30 portion 31 and the curved fire tubes 43 out a flue 31 outlet 57. The flue outlet 57 can be connected to a 32 flue pipe for carrying away waste gas.

~ 3 l A suitable heat source, such as the forced draft 2 burner 59, is mounted in a central opening provided in 3 the flue collector 55 and the mounting portion 37 of 4 the assembly. The ~orced draft burner 5~, as shown in Figure 1, has a nozzle 61 which communicates with the 6 interior o~ the combustion chamber portion 31, whereby 7 heat from the burner 59 passes through the interior of 8 the submerged combustion chamber 31, through the fire 9 tubes 43, and into the annular chamber of the flue collector 55 before passing to the flue outlet 57.

12 The forced draft heating module 29 is described in 13 detail in United States Patent No. 4,465,024, assigned to 14 the assignee of the present invention. The module is 15 commercially available from PVI Industries, Inc., Fort 16 Worth, Texas as the TURBOPOWER module. However, as will ~7 be apparent to those skilled in the art, other heaters, 18 lncludlng electric heaters are within the scope of this 19 lnventlOn .

24 As will further be understood by those skilled in the art, the present invention has application to 26 potable, hot water storage vessels and water heaters 27 having vessel bodies of the vertical tube type which 28 -utilizes fire tubes located above a combustion chamber.
2g As best seen in Figure 2, a flexible, non-molded 31 liner 63 is installed within the vessel body 13 through 32 the initially open end 25. The liner 63 has tubular 33 sidewalls 65, a closed end 67 at one extent and an 'C g .~ .

2C~9273 1 oppositely arranged open end 69 at the opposite extent.
2 In the embodiment shown, the open end 69 iS adapted to 3 receive the heat generating means, in this case forced 4 draft heating module 29.

6 The liner 63 is fabricated from a homogeneous, 7 polymeric material and is preferably either extruded 8 or calendered in thin sheet form prior to installation 9 within the vessel body 13. As will be explained, the sheet material is formed into an envelope or "bag"
11 shape having a closed end 67 by joining one or more 12 seams or weld lines.

14 The material selected for the liner 63 can conveniently comprise any of a number of non-molded, 16 flexible, polymeric materials. For instance, natural 17 and synthetic elastomers, polyolefines, vinyl plastics 18 EPDM, PVC, and the like. The candidate material must 19 meet the requisite criteria of being joinable to form 20 an envelope or "bag" shape, have the necessary heat 21 resistance for the intended application (typically 22 above about 190~F), and meet FDA approval for potable 23 water storage. In the embodiment shown, the liner 63 24 is a polyvinyl chloride having a softening point above 25 about 200~F. Polyvinyl chloride sheet material of the 26 type under consideration will be familiar to those 27 skilled in the art and is used, for instance, as above 28 ground swimming pool liners, as liners for water beds, 29 and the like.
31 As shown in Figure 2, the liner open end 69 is 3 2 preferably provided with a peripheral lip portion 71 33 which has a plurality of bolt openings 73 adapted to 2~92~

1 mate with the bolt openings 75 contained in the flange 2 portion 41 of the vessel end 25. The lip portion 71 is 3 formed of a polymeric material which is compatible with 4 the material of the remainder of the liner and which can be fused or vulcanized to the liner 63. In the 6 embodiment shown, the lip portion is injection molded 7 PVC.

9 ~epending upon the materials selected, a variety of techniques are known in the art for joining the lip 11 portion 71 to the liner 63 and for sealing the liner 12 seams. For instance, in the case of EPDM the lip 13 portion and seams are overlapped, the vessel open end 14 is closed, and the vessel interior is pressurized with steam at about 325-350~F to vulcanize the lip and seams 16 to the liner. Other methods for joining the selected 17 polymeric materials will be apparent to those skilled 18 in the art including fusing, vulcanizing and the 19 application of adhesive.
21 The flange portion 41 of the vessel 13 can also be 22 provided with an O-ring groove 77 for receiving an O-23 ring to provide improved sealing with the mounting 24 portion 37 of the heat generating means 29.
26 The flexible liner 63 is provided with a plurality 27 of ports in the tubular sidewalls thereof to 28 accommodate, for instance, the water inlet 79 and 29 opening for the pressure relief fitting 81 shown in Figure 2. As shown in greater detail in Figures 3 and 31 4, each port 83 provided in the liner 63 is formed of a 32 polymeric material, such as a natural or synthetic 33 elastomer which can be, for instance, injection molded ""-- 2~SJ~I~t73 1 and which can be joined to the remainder of the liner, 2 as by welding, fusing or vulcanizing. In the 3 embodiment shown, the ports 83 are dielectrically 4 welded to the liner 63. Each port includes an outwardly extending collar 85 and an integral O-ring portion 87 6 which extends through the opening provided in the 7 vessel body 13 to the exterior thereof.

9 The outwardly extending collar 85 and O-ring portion 87 comprise a gasket member 89 for the flexible 11 liner 63 to facilitate the attachment of a selected 12 fitting onto the vessel exterior. The O-ring portion 13 is of a greater diameter than the port opening 91 14 provided in the liner and the vessel opening so that the O-ring portion overlays the vessel opening when the 16 liner is installed (Figure 3).

18 As shown in Figure 4, the exterior of the vessel 19 body is preferably provided with a plurality of outwardly extending bolts 93 adjacent each of the 21 vessel openings. Preferably, the bolts 93 are stud 22 welded by known resistance welding techniques so that 23 the studs fuse and penetrate into the steel of the 24 vessel sidewall.
26 Each bolt 93 is adapted to be received within the 27 mating bolt opening 95 provided in a bolt-on flange 97, 28 whereby the integral O-ring portion 87 of each liner 29 collar is sandwiched between the bolt-on flange 97 and the exterior of the vessel body 13 when the flange is 31 installed on the vessel. The flange 97 could be 32 equipped, for example, with a two inch NPT opening used 33 as a pipe coupling, or could be designed to receive 2~3aX~73 1 other fittings, such as an electric heating element.
2 Any type fitting can be utilized with the flange and 3 liner of the invention.

As shown in Figures 5-8, the flange 97 includes a 6 body 99 having an inner surface 101 adapted to be 7 supported at the selected location on the vessel 8 exterior by the bolts 93. A central opening 103, in 9 this case, is a two inch NPT threaded opening for use as a pipe coupling. The body 99 is generally square 11 with the bolt openings 95 being equidistantly spaced 12 about the periphery 105 of the body and communicate the 13 inner and outer surfaces 101, 107. In some 14 embodiments, a retaining means may be provided for maintaining the position of the O-ring portion 87 of 16 the liner collar 85 on the inner surface 101 of the 17 flange. Preferably, the retaining means is an O-ring 18 groove which is located between the bolt openings 93 19 and the central opening 103 of the flange 97.
21 The inner surface 101 of the flange body 99 is 22 concave, being curved about both a horizontal and a 23 vertical axis 111, 113 (Figure 6) respectively, drawn 24 to bisect the body 99. In this way, the inner surface 101 forms a spherical-shaped void (Figure 7) with the 26 bolt openings 93 forming isolated points of contact 27 with the vessel exterior when the flange is bolted into 28 position. The doubly curved inner surfaces are 29 illustrated as 115, 117 in Figures 7 and 8. The radius of curvature employed for each curved inner surface 31 (101 in Figure 5) is not critical as long as the radius 32 is the same as or smaller than that of the mating 33 surface to which the flange is being attached, in this ~ 2C3 ~92~73 1 case, vessel exterior 119. The radius of curvature for 2 the doubly curved surfaces 45, 47 (Figure 7 and 8) can 3 be identical. As long as the radius of curvature of 4 the inner surface 101 is smaller than the radius of the vessel exterior surface which is to be fit, the flange 6 will rest on four points adjacent the bolt openings 93.
7 In this way, when the nuts 121 are tightened on the 8 threaded shafts of the bolts 93 during the flange 9 installation, the flange will not be bent or stressed.
11 The O-ring portion 87 of the liner collar 85 must 12 be of a cross-sectional diameter so that a seal is 13 formed when the four corners of the flange touch the 14 vessel exterior. Otherwise, the O-ring dimensions or type of materials is not critical.

17 The method of lining a potable, hot water storage 18 vessel of the invention will now be briefly described.
19 After welding a plurality of outwardly extending bolts 20 93 onto the vessel body 13, the liner can be inserted 21 through the vessel open end 25 with the liner being 22 received within the vessel open interior prior to 23 filling the vessel with water. Each collar 85 is 24 inserted through its mating vessel opening, for example 25 opening 79 in Figure 2, and the lip 71 of the liner is 26 brought to rest upon the flange portion 41 of the 27 vessel body. In some circumstances, it may be 28 desirable to pull a slight vacuum between the liner 63 29 and the open interior of the vessel during the liner 30 installation. This can be accomplished, for instance, 31 by providing a 1/8" pipe tap hole in the vessel body 32 which is later plugged. The heat generating means 29 33 is then inserted within the vessel interior and within - 14- .

2~ '73 1 the interior of the liner 63 with the ring like extent 2 39 of the mounting portion being received over the 3 peripheral lip 71 of the liner. The mounting portion 4 37 of the heat generating means is then secured to the vessel body 13, as by a plurality of bolts 123 which 6 are passed through the openings in the ring like extent 7 39, through the openings in the liner peripheral lip 71 8 and through the mating openings provided in the flange 9 portion 41 of the vessel body.
11 Although, in the preferred form shown, the liner 12 contacts the interior sidewalls of the vessel body 13, 13 it will be understood that a gap can exist between the 14 liner and the vessel interior. The gap can be void or can be filled with a liquid, a gas, or insulative 16 materials. In any case, the liner must be replaceable 17 and removable from within the vessel interior.

19 An invention has been provided with several advantages. The flexible liner of the invention 21 replaces more costly and time consuming lining 22 techniques. The liner effectively protects the vessel 23 interior from cont~;n~tion and corrosion ensuring a 24 supply of potable water fit for human consumption. The liner can be formed from a variety of commercially 26 available materials which are resistant to attack by 27 the common corrosive elements found in water. In order 28 to replace a worn or damaged liner, it is only 29 necessary to remove the mounting portion of the vessel and pull the liner from the vessel interior. The 31 integral port collars provided as a part of the liner 32 assist in positioning the liner within the vessel 33 interior and cooperate with mating bolt-on flanges to 2C~9~73 1 provide effective seals for a variety of vessel 2 fittings. Because the flange can be bolted-on, it is 3 not distorted by heat associated with prior art welding 4 techniques. The positioning bolts can be stud welded in a matter of seconds to the vessel exterior and the 6 bolt-on flange can thereafter be installed much more 7 quickly than with the welding steps involved in welding 8 the prior art flange to the vessel exterior. Because 9 of the curvature of the inner surface of the flange body, the flange sits on its four peripheral corners 11 forming a compression seal with the integral O-ring 12 portion of the liner collar and the vessel exterior.
13 There is no tendency to bend or flatten the flange as 14 would happen if the inner surface were flat. The flange can be economically produced from a variety of 16 materials and by a variety of techniques. For 17 instance, the flange can be stamped or cast from steel, 18 bronze, cast iron and the like.

While the invention has been shown in only one of 21 its forms, it is not thus limited but is susceptible to 22 various changes and modifications without departing 23 from the spirit thereof.

Claims (10)

1. A potable, hot water storage vessel, comprising:
a metallic body having an interior, an exterior, tubular sidewalls and a pair of opposing ends, the metallic body having a water inlet, a water outlet and at least one additional opening for receiving a heat generating means;
a flexible, non-molded liner removably installed within the metallic body through the additional opening prior to filling the vessel with water, the liner having water inlet and water outlet ports which extend through the vessel water inlet and water outlets, respectively, to the exterior of the metallic body, the liner inlet and outlet ports being formed of flexible, polymeric materials which are joined to the liner prior to inserting the liner within the vessel interior;
a heat generating means installed within the additional opening; and means for closing the additional opening once the liner and heat generating means are installed.

2. The potable, hot water storage vessel of claim 1, wherein the liner has tubular sidewalls, a closed end at one extent and an oppositely arranged open end at the opposite extent, the open end being adapted to receive the heat generating means.

3. The potable, hot water storage vessel of claim 2, wherein the water inlet and water outlet ports include an outwardly extending collar and an integral 0-ring portion which extends through the water inlet and water outlet of the metallic body to the exterior thereof.

4. The potable, hot water storage vessel of claim 3, wherein the exterior of the metallic body is provided with a plurality of outwardly extending bolts adjacent each of the water inlet and water outlet, the outwardly extending bolts being adapted to engage a plurality of mating bolt openings provided in a bolt-on flange, whereby the integral O-ring portion of each liner port is sandwiched between the bolt-on flange and the exterior of the metallic body when the flange is installed on the exterior of the vessel.

5. The potable, hot water storage vessel of claim 4, wherein the bolt-on flange includes a body having an inner surface adapted to be supported at a selected location on the vessel exterior and an outer surface, the mating bolt openings provided in the flange body being spaced about the periphery of the flange body and communicating the inner and outer surfaces thereof, the spacing of the bolt openings being selected to mate with the outwardly extending bolts provided on the vessel exterior, and wherein the inner surface of the bolt-on flange is concave, being curved about both a horizontal and a vertical axis drawn to bisect the flange body, thereby forming a spherical-shaped void on the inner surface, the bolt openings forming isolated points of contact with the vessel exterior when the flange is bolted into position.

6. The potable, hot water storage vessel of claim 5, wherein the flange body has a central opening for receiving an associated fitting, the central opening being located within the periphery of the bolt receiving openings.

7. The potable, hot water storage vessel of claim 6, wherein the inner surface of the flange body includes an O-ring groove located between the central opening and the bolt receiving openings.

8. A method of lining a potable, hot water storage vessel of the type which includes a vessel body for dispensing potable water through a water outlet, the water being supplied through a water inlet, the vessel body having an interior, an exterior and opposing ends and also being provided with at least one additional opening, the method comprising the steps of:
welding a plurality of outwardly extending bolts onto the vessel exterior about the periphery of the water inlet and the water outlet;
removably installing a flexible, non-molded liner within the vessel interior through the additional opening prior to filling the vessel with water, the liner having integrally formed water inlet and water outlet ports;
inserting the liner water inlet and outlet ports through the vessel water inlet and water outlets, respectively, to the exterior of the vessel body;
providing a bolt-on flange with a body having an inner surface and an outer surface, the inner surface being provided with a plurality of bolt openings spaced about the periphery of said body and communicating said inner and outer surfaces;

locating a bolt-on flange on the vessel exterior at each of the water inlet and water outlet by passing the outwardly extending bolts through the bolt openings provided in the flange bodies;
sealing the flanges to the vessel exterior by bolting the flanges onto the vessel with the respective liner ports sandwiched between the vessel exterior and the bolt-on flanges; and closing the additional opening.

9. The method of claim 8, wherein each flange body is provided with an inner surface which is formed doubly concave, being curved about both a horizontal and a vertical axis drawn to bisect the flange body, thereby forming a spherical-shaped void on the flange inner surface, the bolt openings forming isolated points of contact with the vessel exterior when said flange is bolted into position.

10. The method of claim 9, wherein an O-ring groove is provided on the inner surface of each flange body for maintaining the position of said O-ring on the inner surface.