None.
Not applicable.
1. Field of the Invention
The present invention relates generally to pressure vessels, and more particularly to pressure vessels for use in reverse osmosis filtering systems.
2. Description of Related Art
Filtering water to remove impurities is well-known in the art, with various methods and processes known and practiced. For example, simple fiber filtration elements can remove some sediment from water, and activated carbon filtration elements can remove chlorine dissolved in water or other hydrocarbon impurities. Reverse osmosis filtering is a preferred method of desalting or purifying water because it has the capability to remove very small particles and dissolved salts from the water. However, reverse osmosis filtration requires very high pressures in order to force the water being treated through a semi-permeable membrane in order to remove the impurities and dissolved salts. The membranes used for reverse osmosis filtering have physical barrier layer, and are typically designed to allow only water to pass through while preventing the passage of solutes, such as salt ions. Thus, reverse osmosis filtration can be used in the desalination process to purify sea water to drinkable water. Because reverse osmosis filtration requires overcoming the natural osmotic pressure of a fluid being processed, the pressures in reverse osmosis filtration systems are relatively high. For example the natural osmotic pressure for seawater is approximately 800 to 1200 pounds per square inch (p.s.i.). That natural osmotic pressure thus must be overcome in order for the seawater to be forced through a semi-permeable membrane in a reverse osmosis filtration system. Typical reverse osmosis filtration material includes spiral wound membranes.
Reverse osmosis filtering systems typically use a high pressure pump to force the solution being treated, such as water, through the semi-permeable membrane. The membrane allows only the smaller water molecules to pass through, while trapping impurities and dissolved salts. Reverse osmosis filtering can thus remove solids, organics, submicron colloidal material, and even viruses and bacteria from the water.
Because of the high pressures involved, conventional reverse osmosis filtration systems employ pressure vessels made of strong, pressure resistant materials, such as thick PVC, stainless steel, and fiberglass, with the accompanying components of the pressure vessel (seal plates, load plates, ports, etc.) made of similarly strong, pressure resistant materials. While these existing systems are generally effective, the thicknesses of material required to handle the reverse osmosis pressures lead to large, heavy pressure vessels that do not provide the most efficient filtration capability for the footprint and weight of the pressure vessel.
Thus, there remains a need in the art for stronger, lighter weight pressure vessels that provide capability to handle the high pressures of reverse osmosis filtration while also providing increased strength, lighter weight, and providing simpler and more effective features to allow increased filtration capacity and easier maintenance.
The present invention is directed to reverse osmosis pressure vessels.
In one aspect, exemplary embodiments of the present invention provide a reverse osmosis pressure vessel end cap assembly. The end cap assembly includes a seal plate positioned within a pressure vessel shell, with one or more load plates positioned to retain the seal plate in position. One or more load rings are captured and supported between adjacent load plates with the load ring engaged within a channel in the shell to contain the pressure exerted upon the load plates. The end cap assembly thus provides secure yet easily removable access to the pressure vessel, capable of withstanding the high pressures of a reverse osmosis filtration system.
In another aspect, exemplary embodiments of the present invention provide a reverse osmosis pressure vessel having a tapered side port. The tapered side port fitting is mated within a corresponding aperture in the pressure vessel shell. The angle of the taper disperses forces exerted on the port fitting perpendicularly outwardly to the wall of the process port through the wall of the pressure vessel, permitting a thinner-walled vessel to be employed.
In yet another aspect, exemplary embodiments of the present invention provide a reverse osmosis pressure vessel having a wedge shaped non-metallic load transfer member (referred to herein as “load transfer member”) that bears the thrust load from the load plate. The load transfer member is preferably bonded with a fiber reinforced resin composite (FRRC) material used to form the walls of the pressure vessel, with the slope of the wedge-shaped member providing a smooth transition for wound FRRC material during the manufacture of the pressure vessel.
Additional aspects of the invention, together with the advantages and novel features appurtenant thereto, will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The present invention will be described in greater detail in the following detailed description of the invention with reference to the accompanying drawings that form a part hereof, in which:
Reverse osmosis pressure vessels in accordance with various exemplary embodiments of the present invention are depicted in
Looking first to
Pressure vessel 102 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 102 is manufactured by winding resin coated glass/carbon fibers around a mandrel to produce a hard shell pressure vessel. Fiber reinforced resin composites (FRRC) provide greater strength and thus allow a correspondingly thinner wall for a pressure vessel resulting in a lighter, thinner-walled vessel as compared to conventional materials. FRRC is particularly beneficial in use with large scale reverse osmosis filtering systems which employ high pressures and occupy a large area.
Looking still to
First load plate 126, a generally cylindrical plate having eight bolt holes and a center aperture extending there through, is positioned directly adjacent seal plate 118. Second load plate 128, a generally cylindrical plate, also has eight bolt holes and a center aperture extending there through, corresponding to and aligning with the holes in first load plate 126. Second load plate 128 further includes a step on its perimeter to a smaller diameter portion 129 on the interior side of the load plate 128, facing and adjacent to first load plate 126. Third load plate 130 is likewise a generally cylindrical plate having eight bolt holes and a center aperture extending there through, corresponding to and aligning with the holes in the first and second load plates. Third load plate 130 also includes a step on its perimeter to a small diameter portion 131 on the interior side of the load plate 130, facing and adjacent to second load plate 128.
Seal plate 118 is preferably made from a rigid, non-corrosive material such as PVC. First, second and third load plates 126, 128, 130 are preferably made from a rigid material such as metal. Most preferably the load plates are made from a strong, lightweight material such as aluminum or a composite material capable of withstanding high pressures and corrosive environments present in reverse osmosis filtering systems.
Hex bolts 124 extend from the interior side of first load plate 126, and through the bolt holes in all three load plates 126, 128, 130 to corresponding lock washers 140, washers 142, and nuts 144. Thus, hex bolts 124 and associated washers and nuts secure the three load plates together. As can be seen in
Finally, segmented load rings 136 (comprising discrete segments 136a, 136b, 136c) and 138 (comprising discrete segments 138a, 138b, 138c) are positioned around the smaller diameter portions 129 and 131 of second and third load plates 128, 130, respectively. Load rings 136, 138 preferably have a generally square cross-sectional profile and conform to the shape of corresponding channels 110 and 112 in the interior surface of the pressure vessel.
As can best be seen in
With eight hex bolts 124 extending through their respective bolt holes in the seal plate and load plates, tightening lock washers 140, washers 142, and nuts 144 onto the hex bolts draw the load plates together, with the stepped portions 129, 131 of the second and third load plates thus capturing the load rings 136, 138 into the channels 110, 112 in the interior surface of the pressure vessel. With the bolts, lock washers, washers, and nuts fully tightened the load rings 136, 138 are captured and engage into grooves 110, 112 to completely secure the seal plate and load plates within the pressure vessel. Thus, the seal plate is prevented from moving when presented with the high reverse osmosis filtering pressures present in the pressure vessel during operation. As described previously, permeate tube 114 provides an outlet for filtered fluid to exit the pressure vessel after passing through the filtration material in the vessel, with O-rings 132a, 132b providing a seal for the permeate tube.
Other alternative embodiments and configurations are anticipated by the present invention. For example, while eight hex bolts and associated washers and nuts are depicted, other fastener types, or a different number of fasteners may be used. And while the seal plate and load plates are shown with center apertures for a permeate tube, other configurations are within the scope of the present invention. For example, the seal plate and load plates may have no center aperture or permeate tube, with the pressure vessel providing a side port or other fluid port. These and other alternatives are contemplated by the present invention.
Looking to
Pressure vessel 202 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 202 is manufactured by winding resin coated glass/carbon fibers around a mandrel to produce a hard shell pressure vessel as described previously.
Looking still to
First load plate 226, a generally cylindrical plate having eight bolt holes and a center aperture extending there through is positioned directly adjacent seal plate 218. The first load plate further includes a chamfered portion 246 tapering to a smaller diameter on the exterior side of the load plate 226, facing and adjacent to second load plate 228. Second load plate 228, a generally cylindrical plate, also has eight bolt holes and a center aperture extending there through, corresponding to and aligning with the holes in first load plate 226. Second load plate 228 further includes two chamfered portions; 229 tapering to a smaller diameter on the interior side of the load plate 228, facing and adjacent to first load plate 226 and 248 tapering to a smaller diameter on the exterior side of the load plate 228, facing and adjacent to the third load plate 230. Third load plate 230 is likewise a generally cylindrical plate having eight bolt holes and a center aperture extending there through, corresponding to and aligning with the holes in the first and second load plates. Third load plate 230 also includes a chamfered portion 231 tapering to a smaller diameter on the interior side of the load plate 231, facing and adjacent to second load plate 228.
Seal plate 218 is preferably made from a rigid, non-corrosive material such as PVC. First, second and third load plates 226, 228, 230 are preferably made from a rigid material such as metal. Most preferably the load plates are made from a strong, lightweight material such as aluminum or a composite material capable of withstanding high pressures and corrosive environments present in reverse osmosis filtering systems.
Hex bolts 224 extend from the interior side of first load plate 226, and through the bolt holes in all three load plates 226, 228, 230 to corresponding lock washers 240, washers 242, and nuts 244. Thus, hex bolts 224 and associated washers and nuts secure the three load plates together. As can be seen in
Finally, load rings 236 and 238 are positioned around the chamfered portions 246 and 229 of the first and second load plates and 248 and 231 of the second and third load plates respectively. Load rings 236, 238 preferably have a circular cross-sectional profile and conform to the shape of corresponding channels 210 and 212 in the interior surface of the pressure vessel. Load rings 236, 238 are nearly contiguous, but each includes a gap (237 and 239, respectively) to allow the load ring to expand radially outwardly.
As can best be seen in
With eight hex bolts 224 extending through their respective bolt holes in the seal plate and load plates, tightening lock washers 240, washers 242, and nuts 244 onto the hex bolts draw the three load plates together, with the chamfered portions of the first and second load plates capturing load ring 236 within channel 210 and the chamfered portions 246, 229, 231 of the second and third load plates capturing load ring 238 within channel 212 in the interior surface of the pressure vessel. With the bolts, lock washers, washers, and nuts fully tightened the load rings 236, 238 are captured and engage with channels 210, 212 to completely secure the seal plate and load plates within the pressure vessel. Thus, the seal plate is prevented from moving when presented with the high reverse osmosis filtering pressures present in the pressure vessel during operation. As described previously, permeate tube 214 provides an outlet for filtered fluid to exit the pressure vessel after passing through the filtration material in the vessel, with O-rings 232a, 232b providing a seal for the permeate tube.
Other alternative embodiments and configurations are anticipated by the present invention. For example, while eight hex bolts and associated washers and nuts are depicted, other fastener types, or a different number of fasteners may be used. And while the seal plate and load plates are shown with center apertures for a permeate tube, other configurations are within the scope of the present invention. For example, the seal plate and load plates may have no center aperture or permeate tube, with the pressure vessel providing a side port or other fluid port. These and other alternatives are contemplated by the present invention.
Looking to
Pressure vessel 252 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 252 is manufactured by winding resin coated glass/carbon fibers around a mandrel to produce a hard shell pressure vessel as described previously.
Looking still to
First load plate 276, a generally cylindrical plate having twelve bolt holes and a center aperture extending there through is positioned directly adjacent seal plate 268. First load plate 276 includes a chamfered portion 279 tapering to a smaller diameter and extending circumferentially around the load plate and facing outwardly towards end 254 of the pressure vessel. Second load plate 278, a generally cylindrical plate, also has twelve bolt holes and a center aperture extending there through, corresponding to and aligning with the holes in first load plate 276. Second load plate 278 also includes a chamfered portion 281 tapering to a smaller diameter on the interior side of the load plate 278, facing and adjacent to first load plate 276.
Seal plate 268, and first and second load plates 276, 278 are preferably made from a rigid material such as metal. Most preferably they are made from a strong, lightweight material such as aluminum or a composite material capable of withstanding high pressures and corrosive environments present in reverse osmosis filtering systems.
Hex bolts 274 extend from the exterior side of second load plate 278 through the bolt holes in the second load plate and into corresponding threaded apertures 294 in first load plate 276. Thus, the hex bolts 224 tighten into the threaded apertures to secure the two load plates together. Second load plate 278 may include recessed areas surrounding each bolt hole on the exterior face of the plate to allow the heads of the hex bolts 274 to be recessed below, or protrude minimally from, the surface of the load plate. As can be seen in
Load ring 286 is positioned around the chamfered portions 279 and 281 of the first and second load plates. Load ring 286 preferably has a generally elongated cross-sectional profile and fits within corresponding channel 260 in the interior surface of the pressure vessel. Load ring 286 is nearly contiguous, but includes a gap 287 to allow the load ring to expand outwardly radially.
As can best be seen in
With twelve hex bolts 274 extending through their respective bolt holes in the seal plate and load plates, tightening the bolts into the corresponding threaded apertures 294 draws load plates 276, 278 together, with the chamfered portions 279, 281 thus forcing load ring 286 radially outwardly, into channel 260 in the interior surface of the pressure vessel. With the bolts fully tightened the load ring 286 is captured and engaged with channel 260 and forced outwardly into the channel to completely secure the seal plate and load plates within the pressure vessel. Thus, the seal plate is prevented from moving when presented with the high reverse osmosis filtering pressures present in the pressure vessel during operation. As described previously, permeate tube 264 provides an outlet for filtered fluid to exit the pressure vessel after passing through the filtration material in the vessel, with O-rings 282a, 282b providing a seal for the permeate tube.
Other alternative embodiments and configurations are anticipated by the present invention. For example, while twelve hex bolts and associated washers and nuts are depicted, other fastener types, or a different number of fasteners may be used. And while the seal plate and load plates are shown with center apertures for a permeate tube, other configurations are within the scope of the present invention. For example, the seal plate and load plates may have no center aperture or permeate tube, with the pressure vessel providing a side port or other fluid port. These and other alternatives are contemplated by the present invention
Turning to
Pressure vessel 302 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 302 is manufactured by winding resin coated glass/carbon fiber around a mandrel to produce a hard shell pressure vessel as described previously.
Looking still to
First load plate 326, a generally cylindrical plate having a center aperture extending there through is positioned directly adjacent seal plate 318. First load plate 326 includes a protruding, chamfered boss 327 on the face opposite the seal plate, the boss extending outwardly towards the open end of the pressure vessel. Boss 327 includes three threaded apertures on its face, each aperture configured to receive a mating fastener. Snap ring 338 is installed in groove 339 on permeate tube 314 after assembly with seal plate and first load plate. Snap ring 338 keeps the seal plate and load plate positioned square on the permeate tube for assembly. Second load plate 328, a generally cylindrical plate, also includes a center aperture extending there through, corresponding to and aligning with the center aperture in first load plate 326. Second load plate 328 further includes a protruding, chamfered boss 329 on the face facing the seal plate, the boss extending inwardly towards the interior of the pressure vessel.
Seal plate 318 is preferably made from a rigid, non-corrosive material such as PVC. First and second load plates 326, 328 are preferably made from a rigid material such as metal. Most preferably the load plates are made from a strong, lightweight material such as aluminum or a composite material capable of withstanding high pressures and corrosive environments present in reverse osmosis filtering systems.
Three fastener bolts 324 extend from the exterior face of second load plate 328, through corresponding bolt holes in the second load plate, and to the threaded apertures in the chamfered boss 327 of first load plate 326. Thus, bolts 324 secure the two load plates together. As can be seen in
Finally, load ring segments 336a, 336b, 336c are positioned around the facing chamfered bosses 327, 329 of first and second load plates 326, 328 respectively, with spacers 337a, 337b, 337c positioned between the adjacent segments. Load ring segments 336a, 336b, 336c are preferably substantially identical and have a tapered or wedge-shaped profile to conform to the shape of corresponding channel 310 in the interior surface of the pressure vessel.
As can best be seen in
With the three fastener bolts 324 extending through the respective bolt holes in second load plate 328 and into the threaded apertures of chamfered boss 327, tightening the bolts draws the two load plates together, with the chamfered boss portions 327, 329 of the load plates thus forcing the load ring segments 336a, 336b, 336c and spacers 337a, 337b, 337c radially outwardly, into channel 310 in the interior surface of the pressure vessel. With the fastener bolts 324 fully tightened the load ring segments are expanded fully outwardly to completely secure the seal plate and load plates within the pressure vessel. Thus, the seal plate is prevented from moving when presented with the high reverse osmosis filtering pressures present in the pressure vessel during operation. As described previously, permeate tube 314 provides an outlet for filtered fluid to exit the pressure vessel after passing through the filtration material in the vessel, with O-rings 332a, 332b providing a seal for the permeate tube.
Other alternative embodiments and configurations are anticipated by the present invention. For example, while three fastener bolts and threaded apertures are depicted, other fastener types, or a different number of fasteners may be used. And while the seal plate and load plates are shown with center apertures for a permeate tube, other configurations are within the scope of the present invention. For example, the seal plate and load plates may have no center aperture or permeate tube, with the pressure vessel providing a side port or other fluid port. These and other alternatives are contemplated by the present invention.
Looking to
Pressure vessel 402 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 402 is manufactured by winding resin coated glass/carbon fiber around a mandrel to produce a hard shell pressure vessel as described previously.
Looking still to
Load ring segments 436a, 436b, 436c are positioned around the perimeter of the interior cavity 409, around sleeve 430. Sleeve 430 is a generally cylindrical tube, with a lip 431 extending radially outward from the exterior end of the sleeve. Load ring segments 436a, 436b, 436c are preferably similar but are sectioned for installation and removal without the need for spacers. Each load ring segment has a generally wedge-shaped profile to conform to the shape of corresponding channel 410 in the interior surface of the pressure vessel.
As can best be seen in
With the load ring segments 436a, 436b, 436c positioned loosely in recess 410, pressing sleeve 430 inwardly towards the interior of the pressure vessel positions the load ring segments radially into channel 410 in the interior surface of the pressure vessel. Thus, the collar and load plates are prevented from moving when presented with the high reverse osmosis filtering pressures present in the pressure vessel during operation. As described previously, permeate tube 414 provides an outlet for filtered fluid to exit the pressure vessel after passing through the filtration material in the vessel, with O-rings 432a, 432b positioned in interior grooves 421, 423 of the seal plate 426 to provide a seal for the permeate tube. Lip 431 on the exterior end of sleeve 430 provides a grip surface to remove the sleeve thereby releasing the load ring segments for removal as necessary.
Other alternative embodiments and configurations are anticipated by the present invention. For example, the seal plate and load plate may have no center aperture or permeate tube, with the pressure vessel providing a side port or other fluid port. Or, the load rings could comprise one or more spacers to position the segments, such as when the load ring is segmented radially. These and other alternatives are contemplated by the present invention.
Looking to
As depicted in this exemplary embodiment, shell 502 has at least one open end to allow insertion and removal of a reverse osmosis filter membrane material, such as a spiral wound membrane element, with an end cap assembly as described previously sealing the filtration material within the vessel.
Shell 502 is preferably made from a strong, rigid material capable of withstanding high pressures present in reverse osmosis filtering systems, such as fiber reinforced plastic, fiber reinforced polyester, glass reinforced polyester, or glass reinforced epoxy (GRE). Most preferably, pressure vessel 502 is manufactured by winding resin coated glass/carbon fiber around a mandrel to produce a hard shell pressure vessel as described previously.
An aperture 510 extends through wall 506 of shell 502, the aperture having a smaller diameter at the outer surface of the shell and a larger diameter at the inner surface of the shell so that the aperture is generally tapered from larger to smaller as it extends from the interior surface of the pressure vessel to the exterior through wall 506. As best seen in
Port fitting 520 is shaped similarly to aperture 510, having a smaller diameter upper portion 516 with substantially parallel walls, and a larger diameter lower portion 518 that tapers from a larger diameter at the lower end of the fitting to a smaller diameter at the junction with the upper portion 518. Thus, port fitting 520 is configured to conform to the shape of the aperture 510 formed in the wall 506 of the shell 502. Preferably the walls of lower portion 518 taper at a slope of approximately ten degrees from the axis of the fitting, as do the tapered walls of aperture 510. Port fitting 520 further includes first and second O-rings 512, 514 positioned circumferentially around the fitting to provide a seal between the fitting and wall 506. First O-ring 512 is preferably positioned around the upper portion 516 of the fitting, near the junction of upper and lower portions 516, 518 of the fitting, with the second O-ring 514 positioned on the lower tapered portion 518 of the fitting, near the bottom of the fitting. As best seen in
Looking to
Alternative embodiments and configurations are anticipated by the present invention. For example, the port fitting 520 may have longer or shorter upper and lower portions, with correspondingly different angles of taper on the walls of the lower portion. These and other alternatives are contemplated by the present invention.
Looking to
Preferably, the outer surface of the load transfer member is adhered to the wall of the pressure vessel shell. Most preferably, the outer wall of the pressure vessel shell is also made of FRRC so that the FRRC wall and load transfer member are bonded to form a unitary piece.
Looking to
Most preferably, pressure vessel 600 is formed by placing a load transfer wedge-shaped member 616 on a forming mandrel. FRRC material is then wrapped around the mandrel and load transfer member so that the FRRC material bonds with the wedge-shaped load transfer member to form a bond between the two. The approximately sixteen degree slope of the outer surface of the load transfer member provides a gentle transition for the wound FRRC material so that the material smoothly transitions from the narrower diameter portion of the shell to the greater diameter portion of the shell over the load transfer member. When the formed pressure vessel is removed from the forming mandrel, the load transfer member provides a surface 618 to receive the thrust load due to the high reverse osmosis filtering pressure present in the pressure vessel during operation.
Other alternative embodiments and configurations are anticipated by the present invention. The wedge-shaped member may be manufactured of materials other than FRRC. These and other alternatives are contemplated by the present invention.
It should be apparent to one skilled in the art that the reverse osmosis pressure vessels of the present invention described and illustrated hereinabove with respect to various exemplary embodiments provide several advantages over existing pressure vessel designs. For example, the various end cap assemblies provide simple and effective sealing of reverse osmosis pressure vessels employing high pressures. The tapered side port disperses forces more optimally through the walls of the pressure vessel, allowing thinner walled vessels to be used effectively. And, the wedge-shaped load transfer member provides a load transfer mechanism for lower pressure applications such as brackish water, eliminating the need for costly embedded metallic rings.
While the present invention has been described and illustrated hereinabove with reference to various exemplary embodiments, it should be understood that various modifications could be made to these embodiments without departing from the scope of the invention. Furthermore, the combinations of features depicted in the exemplary embodiments are not limited to those described and shown, the various features of the various combinations may be configured or arranged in combinations other than those shown and described in the exemplary embodiments. Therefore, the invention is not to be limited to the exemplary embodiments described and illustrated hereinabove.