COMPOSITE DIAPHRAGM EXPANSION VESSELS

Abstract

A polymer ring assembly for securing a diaphragm to an inner side of a polymeric vessel, a fiber-reinforced polymeric vessel containing a diaphragm secured using a polymer ring assembly and a method of manufacturing the same. The polymer ring assembly allows for the production of high-quality diaphragm expansion vessels, without the use of metal vessel bodies and metal retaining rings. Also, a ring assembly for securing a diaphragm to an inner side of a polymeric vessel, a fiber-reinforced polymeric vessel containing a diaphragm secured using a ring assembly and a method of manufacturing the same.

Description

BACKGROUND OF INVENTION

Field of Invention

The present invention relates to diaphragm expansion vessels and, more particularly to composite glass-fiber wound polymeric diaphragm expansion vessels and methods for manufacturing the same.

Brief Description of Related Art

A variety of expansion tanks/vessels are well known in the art. Early examples include the design shown in Kirk, Jr., U.S. Pat. No. 3,524,475. In this example, and in most other prior art designs, a flexible diaphragm made of rubber is disposed inside a tank body. The periphery of the diaphragm is held in contact with an inner side of the tank body using a retaining ring, which presses the diaphragm into a channel formed in the side of the tank body. The retaining ring and tank body are both typically made of metal.

BRIEF SUMMARY OF THE INVENTION

The present invention provides embodiments of composite glass-fiber wound polymeric diaphragm expansion vessels. In each exemplary embodiment, a polymer ring assembly reliably secures a flexible diaphragm to an inner side of a polymeric vessel resulting in a polymeric vessel containing a flexible diaphragm secured using the polymer ring assembly. The exemplary embodiments allow for the production of high-quality diaphragm expansion vessels.

According to one aspect, an assembly for installation in a polymer vessel comprises a polymeric upper ring including an outer side, a polymeric lower ring including a recess formed on an inner side, and an elastomeric diaphragm including a lip. The lip is received in the recess and is clenched between the outer side of the upper ring and the inner side of the lower ring by compressive force. An air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm.

According to another aspect, a method for manufacturing a diaphragm expansion vessel comprises providing an assembly including a polymeric upper ring including an outer side, a polymeric lower ring including a recess formed on an inner side, and an elastomeric diaphragm including a bulging lip extended outward from an outer side of the diaphragm. The method comprises positioning the bulging lip of the diaphragm in the recess and clenching the bulging lip of the diaphragm between the outer side of the upper ring and the inner side of the lower ring by compressive force, wherein an air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm. The method comprises providing a polymeric vessel; disposing the assembly within the polymeric vessel; spin-welding the assembly to an inner wall of the polymeric vessel; closing off an open end of the polymeric vessel with an end cap; and wrapping the polymeric vessel and end cap with reinforcing fibers.

According to another aspect, a polymer vessel assembly comprises a polymer vessel having an inner wall, and a polymeric ring assembly welded to the inner wall. The polymeric ring assembly includes a polymeric upper ring including an outer side, the upper ring including a reinforcing insert, a polymeric lower ring including a recess formed on an inner side, and an elastomeric diaphragm including a bulging lip extended outward from an outer side of the diaphragm. The bulging lip is received in the recess and is clenched between the outer side of the upper ring and the inner side of the lower ring by compressive force. The reinforcing insert is radially aligned with and inward of the bulging lip of the diaphragm. An air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm.

The foregoing and other features of the inventions are hereinafter more fully described below, the following description setting forth in detail certain illustrative embodiments of the inventions, these being indicative, however, of but a few of the various ways in which the principles of the present inventions may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the accompanying drawing figures, please note that:

FIG. 1 is a section view of a lower half of a diaphragm expansion vessel according to one aspect before reinforcing fibers have been applied to an outer surface thereof.

FIG. 2 is a section view of a portion of the diaphragm expansion vessel of FIG. 1 after the reinforcing fibers have been applied to an outer surface thereof.

FIG. 3 is a section view of a lower half of a diaphragm expansion vessel according to another aspect before reinforcing fibers have been applied to an outer surface thereof.

FIG. 4 is a section view of a portion of the diaphragm expansion vessel of FIG. 1.

FIG. 5 is a view of a snap ring for the diaphragm expansion vessel of FIG. 1.

FIG. 6 is another section view of a portion of the diaphragm expansion vessel of FIG. 1.

FIG. 7A is a section view of ring assembly and diaphragm for a diaphragm expansion vessel according to another aspect.

FIG. 7B is a section view of a lower half of the diaphragm expansion vessel for the ring assembly and diaphragm of FIG. 7A before reinforcing fibers have been applied to an outer surface thereof.

FIG. 8A is a section view of ring assembly and diaphragm for a diaphragm expansion vessel according to another aspect.

FIG. 8B is a section view of a lower half of the diaphragm expansion vessel for the ring assembly and diaphragm of FIG. 8A before reinforcing fibers have been applied to an outer surface thereof.

FIG. 9 is a section view of a lower half of a diaphragm expansion vessel according to another aspect before reinforcing fibers have been applied to an outer surface thereof.

FIG. 10A is a section view of a portion of the diaphragm expansion vessel of FIG. 9 after the reinforcing fibers have been applied to an outer surface thereof.

FIG. 10B is another section view of a portion of the diaphragm expansion vessel of FIG. 9 after the reinforcing fibers have been applied to an outer surface thereof.

DETAILED DESCRIPTION OF THE INVENTION

It should, of course, be understood that the description and drawings herein are merely illustrative and that various modifications and changes can be made in the structures disclosed without departing from the present disclosure. Spatially relative terms may be used to describe an element and/or feature's relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. Further, any term of degree used herein, such as “substantially”, means a reasonable amount of deviation of the modified word is contemplated such that the end result is not significantly changed. For example, such terms can be construed as allowing a deviation of at least 5% of the modified word if this deviation would not negate the meaning of the word the term of degree modifies.

A. First Embodiment

Referring now to the drawings, wherein like numerals refer to like parts throughout the several views, FIGS. 1 and 2 depict a diaphragm expansion vessel 100 according to one aspect of the present disclosure. The diaphragm expansion vessel 100 includes a polymer ring assembly 102 and a polymeric vessel 104. The polymer ring assembly 102 comprises an upper ring 110 and a lower ring 112, which clench a diaphragm 116 therebetween. The diaphragm 116 is fabricated from an elastomeric material and is generally bowl-shaped. The polymer ring assembly 102 is spin-welded to an inner wall 118 of the polymeric vessel 104.

The upper ring 110 is a molded polymeric structure having an inner side 120, an outer side 122, an upper side 124 and a lower side 126. The inner side 120 is preferably smooth, which prevents damage to the diaphragm 116 that contacts the inner side during use. The outer side 122 includes a spin weld beads 132, which are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104 when the ring assembly 102 is spin-welded to the polymeric vessel. The spin weld beads constitute friction points, which rapidly melt and then re-solidify to form the spin weld when rotation ceases. The upper side 124 is provided with a plurality of pockets 136, which function as drive sockets or features that receive drive pins and thus allow the upper ring 110 to be rotated (i.e., to spin) relative to the polymeric vessel 104 during a spin-welding operation. The pockets 136 can be defined by an annular wall 138, first dividing walls 140, and second dividing walls 142. The annular wall 138 is spaced radially outwardly from the inner side 120 and radially inwardly from the outer side 122. The first dividing walls interconnect the inner side 120 and the annular wall 138. The second dividing walls 142 interconnect the outer side 122 and the annular wall 138. The lower side 126 of the upper ring 110 includes a plurality of teeth 148 in the form of a series of circumferential ridges and valleys. The teeth 148 are configured to engage the diaphragm 116 on a side opposite a circumferential outwardly bulging lip 150 of the diaphragm 116 when the upper ring 110 and lower ring 112 are compressed together with the diaphragm 116 captured or clenched therebetween. The bulging lip 150 is spaced inward proximal to an outer rim of the diaphragm 116. The diaphragm, when so compressed, forms an air-tight and water-tight seal between the upper ring 110 and the lower ring 112.

The lower ring 112 is a composite structure comprising a molded polymeric annular portion 156 having an inner side 158 and an outer side 160. The inner side 158 is canted or angled toward inner wall 118 of the polymeric vessel 104 and includes a recessed area or channel 164 shaped and sized to receive the bulging lip 150 of the diaphragm 116. The lower ring 112 further includes a substantially arcuate portion 168 that extends below the annular portion 156 and includes an inner side 170 and an outer side 172. The diaphragm 116 includes the bulging lip 150 having a complementary shape to the recessed area 164 and includes an outer surface 176 contacting the inner side 158 and the inner side 170. The outer side 160 and the outer side 172 include a plurality of spin weld beads 178, which are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104. The spin weld beads 178 constitute friction points, which rapidly melt when the ring is rotated relative to the inner wall of the polymeric vessel during a spin-welding process and then re-solidify to form a weld when rotation ceases.

The present disclosure provides a method for manufacturing the diaphragm expansion vessel 100. The bulging lip 150 of the diaphragm 116 is placed in the recessed area or channel 164 of the lower ring 112, and then the upper ring 110 is pressed toward the lower ring 112 and diaphragm 116 until the teeth 148 of the upper ring 110 are compressed into the diaphragm. Compression can be accomplished by mechanical means or by pressure (vacuum or air pressure) either before or after the assembly has been placed into the polymeric vessel 104. Once the polymer ring assembly 102 and diaphragm 116 has been positioned where desired within the polymeric vessel 104, the entire assembly (upper ring, lower ring and diaphragm) is then temporarily rotated relative to the polymeric vessel at high speed to spin-weld the compressed assembly to the inner sidewall 118 of the polymeric vessel 104. In accordance with the method, the entire assembly is received by a spin-welding machine. Rapid rotation of the assembly temporarily while the perimeter edge thereof is frictionally contacting the inner surface 118 of the polymeric vessel 104. The generated friction creates local heating, which melt-fuses the polymer ring assembly 102 to the inner side 118 of the polymeric vessel 104, creating a fluid-tight seal. This spin-weld forms an air-tight and water-tight seal between the assembly and the polymeric vessel.

As noted above, an air-tight and water-tight seal is formed between the upper ring 110 and the lower ring 112 by the diaphragm 116, which spans across the polymeric vessel 104 and divides it into a water side and an air side. Once the assembly has been spin-welded to the inner side 118 of the polymeric vessel 104, a domed end cap 180 is spin welded to the open end of the polymeric vessel 104. After the vessel 104 has been sealed, with the polymer ring assembly welded inside, the vessel is preferably wrapped with a reinforcing overwrap layer comprising glass filaments 182, which may be coated with a thermosetting epoxy composition. The glass filaments are wrapped helically and circumferentially around the thermoplastic liner assembly. It will be appreciated that the use of fiber-reinforcing filaments is optional, and that the polymer ring assembly can be used to place a diaphragm in polymeric vessels that are formed by extrusion, blow molding or via rotational casting methods.

B. Second Embodiment

FIGS. 3 and 4 depict a diaphragm expansion vessel 200 according to another aspect of the present disclosure. The diaphragm expansion vessel 200 includes a ring assembly 202 and the polymeric vessel 104. The ring assembly 202 comprises a retaining ring 210 and a metal snap ring 212, which clench a diaphragm 216 therebetween. The diaphragm 216 is fabricated from an elastomeric material and is generally bowl-shaped. The retaining ring 210 is spin-welded to the inner wall 118 of the polymeric vessel 104.

The retaining ring 210 is a composite structure comprising a molded polymeric annular portion 220 and a reinforcing band portion 222 for receiving a reinforcing band 224. The retaining ring 210 has an upper side 226, a lower side 228, an inner side 230, and an outer side 232. The upper side 226 of the retaining ring 210 is provided with a plurality of pockets 236, which function as drive sockets or features that receive drive pins of a spin welding machine and thus allow the retaining ring 210 to be rotated (i.e., to spin) relative to the polymeric vessel 104 during a spin-welding operation. The lower side 228 of the retaining ring is preferably smooth and featureless.

The annular portion 220 of the retaining ring 210 includes an upper portion 246 and a lower portion 248 spaced from the upper portion by reinforcing band portion 222. The outer side 232 of each the upper portion 246 and a lower portion 248 includes at least one spin weld bead 250, which is a circumferential ridge or bump that face the inner wall 118 of the polymeric vessel 104. The spin weld beads 250 constitute friction points, which rapidly melt when the ring assembly 202 is rotated relative to the inner wall 118 of the polymeric vessel 104 during a spin-welding process and then re-solidify to form a weld when rotation ceases.

The inner side 230 of the retaining ring 210 includes a recessed area or channel 256 that is complementary in shape to, and is configured to receive, a bulging lip 258 of the diaphragm 216. The reinforcing band 224 is positioned on the outer side 232 of the reinforcing band portion 222, opposite the channel 256. The reinforcing band 224 can be formed of metal or a polymeric structure that is reinforced by fiberglass wrap to provide hoop strength to resist outward force exerted by the snap-ring 212, and to provide a compression force against the diaphragm 216. A gap 260 is preferably provided between an outer side of the reinforcing band 224 and the inner sidewall 118 of the vessel 104 so that the outer side of the reinforcing band 224 does not interfere with the spin-welding operation. The reinforcing band 224 can be co-molded with the reinforcing band portion 222 or, as explained above, it can be formed on the reinforcing band portion 222 after it has been molded and covered by winding adhesive-coated fibers under tension.

It will be appreciated that injection molding of the retaining ring 210 may result in an out-of-round condition common to injection molded parts. The out-of-round condition can be problematic in spin-welding operations. To eliminate and/or greatly minimize the out-of-round condition, one can apply fiberglass rovings under tension while the retaining ring 210 is fixtured over a nearly-perfectly round mandrel, turned true so that it displays little or no out-of-round condition. If fiberglass rovings are wetted with an epoxy resin-catalyst mixture, and the mixture is allowed to cure while the retaining ring 210 is fixtured over the round mandrel, the retaining ring 210 will conform to and assume the round shape of the mandrel.

The metal snap ring 212 comprises a metal strip, and according to one aspect is manufactured from a band of steel. With additional reference to FIGS. 5 and 6, the snap ring 212 has a first end portion 266 and a second end portion 268. The snap ring 212 is initially formed into a circular shape, with the first end portion 266 extending inward and past the second end portion 268 such that circular shape includes an overlapping portion 270. A joint plate 272 is attached to the first end portion 266 of the snap ring. The joint plate 272 extends along three sides of the metal strip (all except the outwardly facing side) and extends beyond the first end portion of the snap ring 212. The joint plate may be attached to the snap ring by any conventional means, for example, welding. The metal snap ring 212 is configured to be expanded within the retaining ring 210 to capture and hold the flexible diaphragm 216 to the retaining ring. A ring expanding machine can be used to expand the metal snap ring 212. The ring expanding machine presses against the inner side 276 of the metal snap ring in equally spaced apart locations thereby increasing the size of the ring and causing the end portions 266, 268 to approach one another. Once the second end portion 268 passed the first end portion 266, the second end portion slips into the cavity of the joint plate 272 attached to the first end portion. The two end portions 266, 268, now abutting, are retained in that configuration by the joint plate 272. The two end portions can no longer separate, and the snap ring 212 pressed firmly and circumferentially against the flexible diaphragm 216 captured or clenched between the snap ring 212 and the retaining ring 210.

To fabricate the polymeric diaphragm expansion vessel 200 according to this embodiment of the present disclosure, the bulging lip 258 of the diaphragm 216 is placed in the channel 256 of the retaining ring 210, and then the metal snap ring 212 is expanded and locked such that it provides outwards circumferential pressure on the diaphragm 216 opposite the bulging lip 258, creating an air-tight and water-tight seal between the retaining ring 210 and the snap ring 212. The diaphragm 216 and snap ring 212 can be joined to the retaining ring 210 after the retaining ring has been spin-welded to the polymeric vessel. Or, more conveniently, the diaphragm 216 and snap ring 212 can be joined to the retaining ring before the retaining ring has been spin-welded to the polymeric vessel. The retaining ring 210, flexible diaphragm 216 and snap ring 212 can be joined to the polymeric vessel 104 by spin-welding as an assembly.

In either process, the spin-weld forms an air-tight and water-tight seal between the retaining ring 210 and the polymeric vessel 104. As noted above, an air-tight and water-tight seal is formed between the snap ring 212 and the retaining ring 210 by the diaphragm 216, which spans across the polymeric vessel and divides it into a water side and an air side.

The present disclosure provides a method for manufacturing the diaphragm expansion vessel 200. In accordance with the method, the retaining ring assembly 202 is received by the spin-welding machine. The retaining ring 210 is rapidly rotated relative to the polymeric vessel 104 while a perimeter edge of the retaining ring 210 is frictionally contacting the inner surface 118 of the polymeric vessel 104. The generated friction creates local heating, which melt-fuses the ring assembly 202 to the inner side 118 of the polymeric vessel 104, creating a fluid-tight seal. Once the ring assembly 202 has been spin-welded to the inner side 118 of the polymeric vessel, the domed end cap 180 is spin welded to the open end of the polymeric vessel 104. Once the vessel has been sealed, with the ring assembly 202 welded inside, the vessel may be wrapped with the reinforcing overwrap layer 182 comprising glass filaments, which may be coated with a thermosetting epoxy composition.

C. Third Embodiment

FIGS. 7A and 7B depict a diaphragm expansion vessel 300 according to another aspect of the present disclosure. The diaphragm expansion vessel 300 includes a polymeric ring assembly 302 and the polymeric vessel 104. The ring assembly 302 comprises a retaining ring 310 having a first snap ring 312 (i.e., a female snap ring) and a second snap ring 314 (i.e., a male snap ring), which clench a diaphragm 316 therebetween. The diaphragm 316 is fabricated from an elastomeric material and is generally bowl-shaped. The ring assembly 302 is spin-welded to the inner wall 118 of the polymeric vessel 104.

The first snap ring 312 is a molded polymeric structure having an inner side 320, an outer side 322, an upper side 324 and a lower side 326. The inner side 320 is preferably smooth, which prevents damage to the diaphragm 316 that contacts the inner side during use. The outer side 322 includes spin weld beads 332, which are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104 when the ring assembly 302 is spin-welded to the polymeric vessel. The spin weld beads constitute friction points, which rapidly melt and then re-solidify to form the spin weld when rotation ceases. The upper side 324 is provided with tabs 336, which function as drive features that engage drive components of a spin-welding machine and thus allow the first snap ring 312 to be rotated (i.e., to spin) relative to the polymeric vessel 104 during a spin-welding operation. The lower side 326 of the first snap ring 312 defines a channel 340 having a first inner surface 342, a second inner surface 344 opposite the first inner surface in a radial direction, and an upper inner surface 346. The first inner surface 342 is an inner surface of the inner side 320 and is substantially smooth and without interruption. The second inner surface 344 is an inner surface of the outer side 322, is substantially smooth, and includes an interruption in the form of an inner shelf 348. The upper inner surface 346 is an inner surface of the upper side 324. The channel 340 is sized to receive an upper portion of the diaphragm 316 and the second snap ring 314.

The second snap ring 314 is a molded polymeric structure having an inner side 350, an outer side 352, an upper side 354 and a lower side 356. The inner side 350 is preferably smooth, which prevents damage to the diaphragm 316 that contacts the inner side during use. The outer side 352 includes spin weld beads 360, which are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104 when the ring assembly 302 is spin-welded to the polymeric vessel. The spin weld beads constitute friction points, which rapidly melt and then re-solidify to form the spin weld when rotation ceases. The outer side 352 further includes a groove 364 that extends circumferentially along the outer side. The groove 364 is sized to receive at least a section 366 of the second inner surface 344 defined between the inner shelf 348 and that portion of the lower side 326 of the first snap ring 312 that intersects the second inner surface 344.

An upper end portion of the diaphragm 316 includes a circumferential outwardly bulging lip 370 that is received in the channel 340 of the first snap ring 312. The lip 370 is secured in place by the second snap ring 314. The diaphragm 316 when the first snap ring 312 and the second snap ring 314 are connected together is captured or clenched therebetween, particularly between the first inner surface 342 and the inner side 350. The diaphragm 316, when so compressed, forms an air-tight and water-tight seal between the first snap ring 312 and the second snap ring 314. It should be appreciated that the spin-weld forms an air-tight and water-tight seal between the ring assembly 302 and the polymeric vessel 104.

The present disclosure provides a method for manufacturing the diaphragm expansion vessel 300. To fabricate the ring assembly 302 according to this embodiment of the present disclosure, the bulging lip 370 of the diaphragm 316 is placed in the channel 340 of the first snap ring 312. The second snap ring 314 is then placed in the channel 340 so that the section 366 of the second inner surface 344 is received in the groove 364. With the second snap ring 314 secured in place within the channel 340, the inner side 350 is pressed against the diaphragm 316 and the upper side 354 is positioned immediately beneath the bulging lip 370. The second snap ring 314 provides inward circumferential pressure on the diaphragm 316, creating an air-tight and water-tight seal between the first and second snap rings of the retaining ring 310. The retaining ring 310 and the flexible diaphragm 316 can be joined to the polymeric vessel 104 by spin-welding as an assembly. In accordance with the method, the ring assembly 302 is received by the spin-welding machine. The retaining ring 310 is rapidly rotated relative to the polymeric vessel 104 while a perimeter edge of the retaining ring 310 is frictionally contacting the inner surface 118 of the polymeric vessel 104. The generated friction creates local heating, which melt-fuses the ring assembly 302 to the inner side 118 of the polymeric vessel 104, creating a fluid-tight seal. Once the ring assembly 302 has been spin-welded to the inner side 118 of the polymeric vessel, the domed end cap 180 is spin welded to the open end of the polymeric vessel 104. Once the vessel has been sealed, with the ring assembly 302 welded inside, the vessel may be wrapped with the reinforcing overwrap layer 182 comprising glass filaments, which may be coated with a thermosetting epoxy composition.

D. Fourth Embodiment

FIGS. 8A and 8B depict a diaphragm expansion vessel 400 according to another aspect of the present disclosure. The diaphragm expansion vessel 400 includes a ring assembly 402 and the polymeric vessel 104. The ring assembly 402 comprises a retaining ring 410 and a crimp ring 412, which clench a diaphragm 416 therebetween. The diaphragm 416 is fabricated from an elastomeric material and is generally bowl-shaped. The crimp ring 412 is substantially U-shaped and can be a metallic crimp ring or a composite crimp ring. The ring assembly 402 is spin-welded to the inner wall 118 of the polymeric vessel 104.

The retaining ring 410 is a molded polymeric structure having an inner side 420 and an outer side 422. The inner side 420 is preferably smooth, which prevents damage to the diaphragm 416 that contacts the inner side during use. The inner side 420 includes a bulging lip 430 that extends radially inwardly and circumferential about the inner side 420. The outer side 422 includes at least one spin weld bead 432, which is a circumferential ridge or bump that faces the inner wall 118 of the polymeric vessel 104 when the ring assembly 402 is spin-welded to the polymeric vessel. The at least one spin weld bead 432 constitutes a friction point, which rapidly melts and then re-solidifies to form the spin weld when rotation ceases. In the depicted aspect, the retaining ring 410 is step-shaped and includes a first section 440 and a second section 442 below the first section. The first section 440 is offset radially outwardly of the second section 442 to define a wall 444 that extends circumferentially along the retaining ring 410.

The present disclosure provides a method for manufacturing the diaphragm expansion vessel 400. To fabricate the ring assembly 402 according to this embodiment of the present disclosure, an end portion 450 of the diaphragm 416 is wrapped over the second section 442 of the retaining ring 410 that includes the bulging lip 430 on the inner side 420. The end portion 450 abuts the wall 444. The crimp ring 412 is crimped/swaged over the wrapped end portion 450 to secure the diaphragm 416 to the retaining ring 410. With the crimp ring 412 secured in place, the end portion 450 of the diaphragm 416 is pressed against the second section 442, creating an air-tight and water-tight seal between the second section 442 of the retaining ring 410 and the diaphragm 416. The retaining ring 410 and the flexible diaphragm 416 can be joined to the polymeric vessel 104 by spin-welding as an assembly. In accordance with the method, the ring assembly 402 is received by the spin-welding machine. The retaining ring 410 is rapidly rotated relative to the polymeric vessel 104 while a perimeter edge of the retaining ring 410 is frictionally contacting the inner surface 118 of the polymeric vessel 104. The generated friction creates local heating, which melt-fuses the ring assembly 402 to the inner side 118 of the polymeric vessel 104, creating a fluid-tight seal. Once the ring assembly 302 has been spin-welded to the inner side 118 of the polymeric vessel, the domed end cap 180 is spin welded to the open end of the polymeric vessel 104. Once the vessel has been sealed, with the ring assembly welded inside, the vessel may be wrapped with the reinforcing overwrap layer 182 comprising glass filaments, which may be coated with a thermosetting epoxy composition.

E. Fifth Embodiment

FIGS. 9, 10A and 10B depict a diaphragm expansion vessel 500 according to another aspect of the present disclosure. The diaphragm expansion vessel 500 includes a polymer ring assembly 502 and the polymeric vessel 104. The polymer ring assembly 502 comprises an upper ring 510 and a lower ring 512, which clench a diaphragm 516 therebetween. The diaphragm 516 is fabricated from an elastomeric material and is generally bowl-shaped. The polymer ring assembly 502 is spin-welded to the inner wall 118 of the polymeric vessel 104.

The upper ring 510 is a molded polymeric structure having an inner side 520, an outer side 522, an upper side 524 and a lower side 526. The inner side 520 includes a plurality of fins 530, which function as drive features that allow the upper ring 510 to be rotated (i.e., to spin) relative to the polymeric vessel 104 during a spin-welding operation. The outer side 522 includes spin weld beads 532, which are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104 when the ring assembly 502 is spin-welded to the polymeric vessel. The spin weld beads 532 constitute friction points, which rapidly melt and then re-solidify to form the spin weld when rotation ceases. The outer side 522 further includes a plurality of teeth 538 in the form of a series of circumferential ridges and valleys. The teeth 538 are configured to engage the diaphragm 516 on an inner surface opposite a bulging lip 540 of the diaphragm 516 when the upper ring 510 and lower ring 512 are compressed together with the diaphragm 516 captured or clenched therebetween. The bulging lip 540 is extended outwardly and circumferentially on the diaphragm 516, and is spaced inward proximal to an outer rim of the diaphragm 516. The diaphragm, when so compressed, forms an air-tight and water-tight seal between the upper ring 510 and the lower ring 512.

With reference to FIG. 10A, the upper ring 510 is further step-shaped, with a first, upper section 546 spaced radially outwardly from a second, lower section 548, with a base section 550 therebetween. The second section 548 is canted with the lower side 526 radially inwardly of the base section 550. The spin weld beads 532 are provided on the upper section 546 and the teeth 538 are provided on the lower section 548. A first alignment feature 554 for the lower ring 512 is provided on the base section 550. In the depicted aspect, the first alignment feature is a rib 554; although, alternative configurations for the first alignment feature are contemplated.

The lower ring 512 is a composite structure comprising a molded polymeric annular portion 556 having an inner side 558 and an outer side 560. The inner side 558 includes a recessed area or channel 564 shaped and sized to receive the bulging lip 540 of the diaphragm 516. The recessed area is defined by a cylindrical wall portion and an arcuate portion of the inner side 558. The lower ring 512 further includes a substantially arcuate portion 568 that extends below the annular portion 556 and includes an inner side 570, an outer side 572, and a lower side 574. The lower side 574 is angled upwardly toward the lower side 528 of the upper ring 510. A plurality of vanes 576 are present on the outer side 572 of the arcuate portion 568, which provide structural support and strength to the lower ring. The diaphragm 516 includes the bulging lip 540 having a complementary shape to the recessed area 564 and includes an outer surface 578 contacting the inner side 558 and the inner side 570. The outer side 560 and the outer side 572 include a plurality of spin weld beads 580, which again are circumferential ridges or bumps that face the inner wall 118 of the polymeric vessel 104. The spin weld beads 580 constitute friction points, which rapidly melt when the ring is rotated relative to the inner wall of the polymeric vessel during a spin-welding process and then re-solidify to form a weld when rotation ceases. A second alignment feature 582 for mating with the first alignment feature 554 is provided on the annular portion 556. In the depicted aspect, the second alignment feature is a groove 582 shaped complementary to the rib 554.

The outer side 560 of the annular portion 556 includes a channel 586 for receiving a reinforcing band 590. The reinforcing band 590 can be formed of metal or a polymeric structure that is reinforced by fiberglass wrap to provide hoop strength to resist outward force exerted by the upper ring 510, and to provide a compression force against the diaphragm 516. A gap 592 is preferably provided between an outer side of the reinforcing band 590 and the inner sidewall 118 of the vessel 104 so that the outer side of the reinforcing band 590 does not interfere with the spin-welding operation. The reinforcing band 590 can be co-molded with the annular portion 556, or it can be formed on the annular portion 556 after it has been molded and covered by winding adhesive-coated fibers under tension. As shown in FIG. 10A, the reinforcing band 590 is radially outward of the bulging lip 540 of the diaphragm 516 when the lower ring 512 and the upper ring 510 are compressed together with the diaphragm clenched therebetween. The second section 548 of the upper ring 510 includes a reinforcing insert 596, which is co-molded with the upper ring. The reinforcing insert 596 can be T-shaped; although, this is not required. The reinforcing insert 596 is opposite the reinforcing band 590 of the lower ring 512 when the entire assembly 502 is spin-welded to the polymeric vessel 104. It should be appreciated that with the canted orientation of the second section 548 of the upper ring 510, a compression force of the second section 548 with the reinforcing insert 596 is angled slight downward toward the recessed area 564. And a compression force of the lower side 574 of the arcuate portion 568 is angled upward beneath the compression for of the second section 548. These oppositely directed spaced compression forces further compress that portion of the diaphragm below the bulging lip 540 between the upper ring and the lower ring. The reinforcing insert 596 can be formed of metal or other suitable reinforcing material.

With reference to FIG. 10B, an alternative configuration for each of the upper ring and lower ring is depicted. The first alignment feature 554 of the upper ring 510 is a groove formed on the base section 550. The lower ring 512 does not include the reinforcing band 590. The second alignment feature 582 of the lower ring 512 is a rib shaped complementary to the groove 554. Again, other configurations for the first and second alignment features can be utilized, and an O-ring can be placed in the groove 554 to provide further sealing.

The present disclosure provides a method for manufacturing the diaphragm expansion vessel 500. The bulging lip 540 of the diaphragm 516 is placed in the channel 564 of the lower ring 512, and then the upper ring 510 is pressed toward the lower ring and diaphragm 516 until the teeth 538 of the upper ring 510 are compressed into the diaphragm. Compression can be accomplished by mechanical means or by pressure (vacuum or air pressure) either before or after the assembly has been placed into the polymeric vessel 104. Once the polymer ring assembly 502 and diaphragm 516 has been positioned where desired within the polymeric vessel 104, the entire assembly (upper ring, lower ring and diaphragm) is then temporarily rotated relative to the polymeric vessel at high speed to spin-weld the compressed assembly to the inner sidewall 118 of the polymeric vessel 104. In accordance with the method, the entire assembly is received by a spin-welding machine. Rapid rotation of the assembly temporarily while the perimeter edge thereof is frictionally contacting the inner surface 118 of the polymeric vessel 104. The generated friction creates local heating, which melt-fuses the polymer ring assembly 502 to the inner side 118 of the polymeric vessel 104, creating a fluid-tight seal. This spin-weld forms an air-tight and water-tight seal between the assembly and the polymeric vessel.

As noted above, an air-tight and water-tight seal is formed between the upper ring 510 and the lower ring 512 by the diaphragm 516, which spans across the polymeric vessel 104 and divides it into a water side and an air side. Once the assembly has been spin-welded to the inner side 118 of the polymeric vessel 104, the domed end cap 180 is spin welded to the open end of the polymeric vessel 104. After the vessel 104 has been sealed, with the polymer ring assembly welded inside, the vessel may be wrapped with a reinforcing overwrap layer comprising glass filaments 182, which may be coated with a thermosetting epoxy composition.

It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Claims

1. An assembly for installation in a polymer vessel, the assembly comprising: a polymeric upper ring including an outer side;a polymeric lower ring including a recess formed on an inner side; andan elastomeric diaphragm including a lip, the lip is received in the recess and is clenched between the outer side of the upper ring and the inner side of the lower ring by compressive force,wherein an air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm.

2. The assembly of claim 1, wherein the recess is defined a cylindrical wall portion and an arcuate portion of the inner side.

3. The assembly of claim 1, wherein the lip of the diaphragm is a bulging lip that is extended outward from an outer side of the diaphragm.

4. The assembly of claim 3, wherein the outer side of the upper ring comprises a plurality of teeth that engage the diaphragm on an inner surface opposite the bulging lip of the diaphragm when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

5. The assembly of claim 3, wherein a band of reinforcing material is provided on an outer circumferential side of the lower ring.

6. The assembly of claim 5, wherein the outer circumferential side includes a channel and the band or reinforcing material is secured within the channel.

7. The assembly of claim 5, wherein the band of reinforcing material is radially outward of the bulging lip of the diaphragm when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

8. The assembly of claim 3, wherein the outer ring includes a first section and a second section, the first section is spaced radially outward of the second section, the second section includes a reinforcing insert.

9. The assembly of claim 8, wherein a band of reinforcing material is provided on an outer circumferential side of the lower ring, and the reinforcing insert is opposite the band of reinforcing material when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

10. The assembly of claim 8, wherein the reinforcing insert is co-molded with the upper ring.

11. The assembly of claim 1, wherein the upper ring includes a first alignment feature, and the lower ring includes a second alignment feature shaped to mate with the first alignment feature.

12. A method for manufacturing a diaphragm expansion vessel comprising: providing an assembly including: a polymeric upper ring including an outer side,a polymeric lower ring including a recess formed on an inner side, andan elastomeric diaphragm including a bulging lip extended outward from an outer side of the diaphragm;positioning the bulging lip of the diaphragm in the recess;clenching the bulging lip of the diaphragm between the outer side of the upper ring and the inner side of the lower ring by compressive force, wherein an air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm;providing a polymeric vessel;disposing the assembly within the polymeric vessel;spin-welding the assembly to an inner wall of the polymeric vessel;closing off an open end of the polymeric vessel with an end cap; andwrapping the polymeric vessel and end cap with reinforcing fibers.

13. The method of claim 12, wherein the outer side of the upper ring comprises a plurality of teeth, and the method includes engaging the diaphragm on an inner surface opposite the bulging lip of the diaphragm with the plurality of teeth when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

14. The method of claim 12, including providing a band of reinforcing material on an outer circumferential side of the lower ring.

15. The method of claim 14, including positioning the band of reinforcing material radially outward of the bulging lip of the diaphragm when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

16. The method of claim 12, including securing a reinforcement insert in the upper ring, and radially aligning the reinforcing insert with the bulging lip of the diaphragm.

17. A polymer vessel assembly comprising: a polymer vessel having an inner wall; anda polymeric ring assembly welded to the inner wall, the polymeric ring assembly including: a polymeric upper ring including an outer side, the upper ring including a reinforcing insert,a polymeric lower ring including a recess formed on an inner side, andan elastomeric diaphragm including a bulging lip extended outward from an outer side of the diaphragm, the bulging lip is received in the recess and is clenched between the outer side of the upper ring and the inner side of the lower ring by compressive force, the reinforcing insert radially aligned with and inward of the bulging lip of the diaphragm,wherein an air-tight and water-tight seal is formed between the lower ring and the upper ring by the diaphragm.

18. The assembly of claim 17, wherein the outer side of the upper ring comprises a plurality of teeth that engage the diaphragm on an inner surface opposite the bulging lip of the diaphragm when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.

19. The assembly of to claim 17, wherein a band of reinforcing material is provided on an outer circumferential side of the lower ring.

20. The assembly of claim 19, wherein the band of reinforcing material is radially outward of the bulging lip of the diaphragm when the lower ring and the upper ring are compressed together with the diaphragm clenched therebetween.