RU2215216C2 - Pressure vessel and method of manufacturing the same - Google Patents

Abstract

FIELD: equipment for transportation and storage of liquids, liquefied gases and non-caking materials. SUBSTANCE: pressure vessel has cocoon-type casing formed by winding of high-strength filaments secured with one another by polymeric binder, internal sealing layer of gas-impermeable material and pole flanges closed in hermetically sealing relationship with covers. Casing is composed of at least two axially joined modular cocoon-type enclosures, which are secured in hermetically sealing relationship by pole flanges of oval-shaped bottoms defining in junction zone hollow annular member for imparting diametric rigidity to composite casing. Method involves manufacturing casing module members from composite material and assembling said members; manufacturing at least two modular sections making cocoon-type enclosure; inserting two modular sections into cylindrical centering sleeve having centering cylindrical channel with inner diameter corresponding to outer diameter of cylindrical surface of modular sections; moving said sections to one another for joining throats of pole flanges and connecting said throats with one another; providing strong and hermetically sealing connection by any of known methods. EFFECT: wider range of processing methods for manufacturing of pressure vessels. 17 cl, 9 dwg

Description

 The invention relates to large-capacity vessels and tanks for transporting and storing liquids, liquefied gases and bulk non-caking substances used in various sectors of the national economy, and can be used in the oil and gas, chemical, food industries and transport.

 A known construction of a railway tank for heavy and aggressive liquids with a diameter of 2.7 m and a length of 16.8 m, made of fiberglass-wound, containing a power shell made integrally with ovaloid bottoms, the wall thickness of which in the cylindrical part is 9.5 mm, and the inner asboplastics sealing protective layer [1].

 The design shortcomings include its structural and technological complexity, a significant limitation of the longitudinal dimension of the vessel with the capabilities of industrial winding equipment, the high cost of technological equipment - a formative resin-sand mandrel, due to significant energy and labor costs for its manufacture, dismantling and disposal of technological waste.

 Also known is a fiberglass high-pressure cylinder and a method for its manufacture, comprising an external power shell made of composite material and an internal sealing shell made of gas-tight material, two metal flanges of the same design mounted on opposite poles of the cylinder, one of which has an opening [2], adopted as prototype, the main advantage of which is a higher manufacturability of the design and the possibility of its manufacture on a reusable mandrel Ania.

 The disadvantages of the known design are the limited possibilities for creating, as well as delivering to the installation site of large tonnage pressure vessels of large and extra large capacity, in particular, on conventional spiral winding machines produced by industry; uniformity of constructive forms of pressure winding vessels for various purposes.

 A known method of manufacturing a sectioned body of pressure vessels from winding fiberglass (see [1], p. 220 ... 221), including the manufacture of a cylindrical section of the body and two oval shaped bottoms that are coaxially connected together, for example, using a pin-bolt or adhesive connections.

 The disadvantage of this method is the increased complexity of manufacturing and the relatively high mass of the pressure vessel body, due to the presence of several connectors and the need to form a complex structure of the endings of the constituent sections, the processing of the base and fastening structural elements.

 There is also known a method of manufacturing a pressure vessel, adopted for the prototype, type "cocoon", including winding glass tape, impregnated with a polymer binder, on the forming module element of the type "cocoon", which is an internal coaxial module of the housing, made previously of two coaxially connected sections-half-windows, having a sealing shell of a gas-tight material enclosed in a thin fiberglass shell, and metal pole flanges glued into the pole holes of the half-windows [2].

 The disadvantages of this method are its technological complexity and high complexity, as well as limited technological capabilities for the manufacture of large-capacity large volumes of pressure vessels, due to the capabilities of the existing winding machine equipment.

 The invention is aimed at expanding the technological capabilities of creating large-capacity pressure vessels for various purposes from composite materials, increasing the manufacturability of their manufacture and transportation to the place of installation and operation, as well as increasing the range of medium and large-capacity tanks for transporting and storing various liquids, liquefied gases and bulk non-caking substances.

 The essence of the invention lies in the fact that in a pressure vessel made of a composite material for transporting and storing liquids, liquefied gases and bulk non-caking materials, comprising a "cocoon" body formed by winding high-strength fibers bonded to each other with a polymer binder, an inner sealing layer of a gas-tight material and pole flanges, hermetically sealed with covers, the vessel body is made of at least two cocoon-type modular shells stacked coaxially, made Caught by winding from composite material, and sealed tightly between the pole flanges of oval shaped bottoms forming a hollow ring element of diametric stiffness (frame) in the joint area, the ring cavity of the frame can be filled with elastic cushioning material that is hermetically glued to the outer surfaces of the joined bottoms and pole adhesive flanges. The bottom surface of the hollow frame forms a cylindrical neck, used for basing and mounting the body on the frame of the vehicle or tank container. Structural and technological holes can be made in the wall of the cylindrical neck of the hollow frame for installing equipment for monitoring the state of the product (substance) and / or ventilation devices or pressure relief valves. The ring cavity of the frame, at least partially, can be filled with ring banding coils of high-strength fibers, bonded to each other and glued to adjacent surfaces with a thermosetting polymer binder. The ring cavity of the frame can be closed externally with a thin-walled cylindrical sleeve made of a strong structural material, for example fiberglass, having strong overlapping adhesive joints with the cylindrical surfaces of both joined modular shell casings. The closed annular cavity of the frame is filled with lightweight rigid cellular aggregate. It can be filled with rigid filling polyurethane foam or rigid syntactic foam. It can also be filled with foam concrete or powder or granular flame retardant in a polymer matrix.

 Docked modular shells of the composite body of the pressure vessel can have substantially different diametrical and / or longitudinal sizes and volumes. In this case, one or more modular shells of the housing may have a conical shape of the middle part of the "cocoon".

 The essence of the method of manufacturing a pressure vessel is that pre-made modular elements of composite material and assemble from them the body of the vessel. By any known method, at least two cocoon-type modular shell sections are made of winding composite material with an internal sealing layer and pole flanges, inserted into a cylindrical centering sleeve (one modular shell on one side, the other on the other), the inner diameter of the centering cylindrical channel which corresponds to the outer diameter of the cylindrical surface of the modular sections, thus ensure their alignment; and then, moving the sections towards each other, they join the necks of the pole flanges and connect them to each other, ensuring the strength and tightness of the connection in any known manner.

 After joining the docked and bonded modular sections, the cavity between their docked bottoms is filled, if necessary, through the technological hole in the wall of the centering sleeve with a filling composition of rigid or flexible polyurethane foam and foamed in a closed forming volume of the sleeve and hollow frame.

 As a centering cylindrical coupling, a thin-walled coupling 8 can be used (Fig. 5), for example, of winding fiberglass, which is a modular element in the construction of the pressure vessel assembly body, fastening the cylindrical and conical parts of the joined modular shells 2 to each other. After connecting the modular shells, the clutch 8 is glued to them in the places of the annular overlapping sections of the interface.

 The technical result of the device is expressed in expanding the technological capabilities of creating large-capacity pressure vessels from composite materials for various purposes due to the possibility of independent (autonomous) manufacturing of modular shell sections of shortened length, convenient for manufacturing on ordinary available equipment (winding machines and autoclaves) and for transportation in disassembled form on place of final installation of the pressure vessel of the design length (height, in the case of vertical installation of the device property). Under the conditions of the same internal pressure in the vessel body, the axial tensile load acting on the connection of the modular shell sections is significantly reduced, and in proportion to the decrease in the diameters of the joined necks of the pole flanges, the number and weight of bolted (or hairpin) joints of the joined sections is reduced. The design has high damping and damping characteristics when exposed to external dynamic loads of longitudinal compression and / or transverse bending, as well as compensation of longitudinal thermoelastic deformations due to the elastic flexibility of the joined bottoms of cocoon-shaped modular shells. The arsenal and assortment of pressure vessels for transporting and storing liquid, gaseous and bulk substances is expanding. The technical result of the proposed method consists in creating technological and production capabilities and conditions for the manufacture of pressure vessels of almost any length (height) using standard industrial equipment using well-known (mastered) high-performance technologies, available production equipment, tools and equipment.

 The invention is illustrated in the drawing, where Fig.1 shows a General view of a composite pressure vessel of the type "cocoon", consisting of three coaxially stacked modular shells of the type "cocoon" made of composite material; figure 2 shows the docking node of two adjacent modular shells, where the annular cavity of the frame is filled with shock-absorbing elastic foam. Figure 3 illustrates the option of docking adjacent sections and fastening them together using a welding ring connection of the necks of the metal pole flanges; and figure 4 is a node for the connection of the bolt connection of the pole flanges of the docked bottoms of the modular shells. Figure 5 shows a variant of the joint, reinforced by an external annular coupling, and figure 6 is a variant of the welded butt joint with a partial banding filling of the annular cavity of the frame with turns of composite material.

 In FIG. 7, Fig. 8, Fig. 9 show typical variants of composite pressure vessels from winding composite materials assembled from modular shells of the "cocoon" type, differing in size and / or geometric shapes.

 The positions in the drawings indicate: 1 - a composite pressure vessel of the type "cocoon"; 2 - modular shells of the type "cocoon" of composite material; 3 - power shell modular shell of high strength winding composite material; 4 - a sealing layer of a modular shell; 5 - pole flange; 6 - connecting element of the docked modular shells; 7 - shock-absorbing and damping elastic filler of the ring frame of the precast structure; 8 - thin-walled cylindrical sleeve made of durable structural material; 9 - ring banding coils of high strength composite material.

 The pressure vessel 1 (figure 1) consists of three identical modular shells of a winding composite material having a cocoon shape and two pole holes.

 Each modular shell 2 contains a power shell 3 of a winding high-strength composite material, a sealing layer 4 of a thermoplastic or elastomeric rubber-like impermeable material and two pole flanges 5 made of high-strength steel, titanium or aluminum alloy, or of composite material.

 The modular shells 2 are aligned coaxially with each other in a composite pressure vessel 1 with their pole flanges 5, which are firmly fastened to each other by any known detachable (Fig. 2, Fig. 4, Fig. 5) or one-piece type of connection 6. Detachable connection 6 (Fig. 2, Fig. 4) can be bolted, hairpin or screw. The tightness of detachable joints is ensured by any known method: elastomeric or plastic gaskets, sealants, etc.

 One-piece joints 6 (FIG. 3, FIG. 5, FIG. 6) can be welded, soldered, glue, glue-screw (FIG. 5). The impermeability of one-piece joints is ensured by the necessary density (impermeability) of the welded, soldered or adhesive joint.

 To increase the reliability and damping and damping qualities of the hollow annular frames of the pressure vessel 1 formed at the joints of the modular shells 2, it is necessary that the end flanges of the docked bottoms of the power shells 3 are joined to each other with an interference fit created by bolt or hairpin joints. In the absence of direct contact and interference on the flange surfaces of the bottoms, i.e. if there is a certain gap between them, the latter should be filled with either adhesive (in the case of a gap type gap), or turns of a fiber bundle (roving) impregnated with a polymer binder (Fig.6), or in a wide annular gap (Fig.3) be installed intermediate burst sleeve, jamming the flange ends of the bottoms, pressing them to the pole flanges 5.

 To increase the strength and rigidity of the pressure vessel 1 in the docking zones of the modular shells 2 under conditions of longitudinal compression and / or transverse bending of the cavity of the ring frames formed by the joined bottoms of the modular shells, they can be filled (if necessary) with some kind of filler 7 of rigid polyurethane foam, syntactic polystyrene foam, cellular concrete (Fig. 2, Fig. 5), or by turns of a fiber tow impregnated with a polymer binder.

 For the dynamic strength of the pressure vessel and the amortization of the energy of longitudinal and bending external loads, the cavity of the ring frame can be filled with an elastomeric porous material 7 (Fig. 2) such as elastic polyurethane foam, foam rubber, etc. In addition, the docking zones of modular shells 2 can be enhanced by the installation of special thin-walled shell couplings 8, for example, from a composite material such as fiberglass (Fig. 5), which significantly increase the strength and rigidity of the structure, protect the butt joints from aggressive environmental influences, and the filler 7 - from erosion and malicious destruction. The clutch 8 is overlapped on the cylindrical and / or conical surfaces of the stacked modular shells 2 (Fig. 5, Fig. 7, Fig. 8, Fig. 9). Overlap joints of couplings and modular shells are filled with moisture-proof adhesive (sealant or high-strength adhesive).

 To increase the strength, rigidity, tightness and cushioning and damping qualities of the pressure vessel in the docking zones of the modular shells forming hollow annular frames, these annular cavities of the frames are partially filled with banding coils of high-strength composite fiber material 9 (Fig. 6), pinching the pole ends of the joined days on the necks of the pole flanges 5. As a filler 7 of the hollow ring frame, a powder flame-retardant composition or an encapsulated liquid can be used ntipiren embedded in a polymer matrix.

 Depending on the specific purpose and field of application, the pressure vessel 1 may consist of a set of stacked modular shells 2, of absolutely identical structural and technological design both in shape, size, and materials used (Fig. 1), or of cylindrical cocoon-shaped modular shells 2 of various diameters and / or lengths and / or composite material and / or type of compounds and / or having any other structural, technological and material differences (Fig. 7); or from modular cocoon shells 2 having various geometric shapes (Fig. 8 and Fig. 9), for example, one of which is cylindrical and the other is conical.

 When used in industrial units of oil and gas and chemical industries, and also as containers for storing bulk materials and viscous liquids, it is advisable to mount a composite pressure vessel 1 on racks or industrial foundations and platforms, placing the axis of symmetry of the vessel vertically to the horizontal plane of the base, since this significantly increases the operational manufacturability of the device, expressed in the simplification and reduction of energy costs for filling and unloading or partial boron content of the product.

 When filling the pressure vessel 1 with a liquid or gaseous product, as well as granular (especially in its horizontal position), the internal pressure of the product contents is transmitted through the sealing elastic layer to the walls of the power shells 3 of the modular shells 2 joined and fastened to each other 2. Under the influence of internal pressure, acting on the docked bottoms of the modular shells, the butt connectors (connections) are compressed on both sides, compacting and unloading the elements of the connection 6 (bolted, or welded, or adhesive, or another type). This ensures the necessary strength, tightness, operational reliability and relatively low weight of the connecting elements (in particular, a significantly smaller number of bolt, screw and hairpin elements, as well as smaller sizes of their diameters).

 The pressure acting on the end bottoms (covered by the covers) of the vessel 1 determines the longitudinal tensile force perceived by the elements of the butt joints (bolts, studs, welds and glues). The magnitude of this effort is determined by the product of the value of the internal pressure of the product contents by the cross-sectional area of the pole holes of the joined pole flanges of the modular shells, i.e. significantly smaller than in the known vessels of the type "cocoon".

 In the case when the cross-sectional area of the pole holes of the joined flanges is less than or equal to the projection area of the ovaloid bottom on the plane of the docking joint, the fastening elements of the composite structure of the pressure vessel 1 are unloaded butt joint sealed (compressed).

 Under the influence of external shock loads of longitudinal compression or lateral bending, the joined thin-walled bottoms of modular shells made of high-strength winding composite material behave like elastic membranes, absorbing and damping the energy of external dynamic shocks and vibrations. If necessary, the shock-absorbing and damping characteristics of the device can be substantially increased by partially filling or completely filling the annular cavity of the butt frames with an elastomer or elastic foam. With a partial filling of the frame cavity, the size of the elastic (shock-absorbing) belt of the membrane decreases, and therefore, its rigidity increases and the dissipation and damping qualities of the joint increase. When the hollow frame is completely filled with an elastomer or elastic foam, the stiffness and efficiency of the shock-absorbing damping elements (frames) of the pressure vessel increases.

 The use of powder or encapsulated anti-foams as a cushioning-damping aggregate of hollow frames increases the fire protection of the device in the presence of an open source of flame near it. To do this, it is enough to shield the cylindrical sections of the modular shells, leaving the zones of the butt frames open. Under the influence of thermal action, the gaseous decomposition products of antifrictions will fill the gap between the screens and the power shells of the modular sections, creating protective wall-mounted atmospheric curtains that prevent the polymer binder composite material from igniting the pressure vessel’s wall.

 A method of manufacturing a pressure vessel includes the manufacture of modular shells of a cocoon shape by any known method of filament (tow) winding using an existing standard winding machine, for example, model KU-421, which makes it possible to produce cocoon shells by the wet method by spiral winding with a diameter of up to 2500 mm and a length up to 9000 mm, related to large-capacity pressure vessels. A sealing layer 4 is formed, for example, of an elastomer such as unvulcanized or vulcanized polyurethane rubbers or rubbers based on ethylene-propylene rubbers and others, a sealing layer 4. For bonding sheet blanks of vulcanized rubbers, rubber-based adhesive systems, for example phenolic rubber glue or glue on butyl rubber base for bonding vulcanized and unvulcanized blanks to each other. Unvulcanized rubber billets are joined by an autogesion method, treating them with gasoline, i.e. without the use of glue. At the ends of the sealing layer 4 on the butyl rubber glue, metal pole flanges 5 are joined, then the structural and technological layer of composite fiber material is wound with spiral turns of bundles (or rovings) impregnated with a polymer binder. After the curing of the structural-technological layer and partial vulcanization of the sealing rubber layer, the resulting technological "cocoon" is cut at least in half with an annular cut perpendicular to the axis of the cocoon and removed from the mandrel. Then both halves (half-cocoons) are again glued to each other, obtaining a cocoon-shaped structural-technological shell-mandrel, on which the power shell 3 is wound with bundles impregnated with a polymer binder, and the final operation of curing the composite material and vulcanization of the sealing rubber layer 4 is performed.

 The two modular casings 2 thus manufactured are telescopically introduced from both sides into a centering process coupling, using the outer cylindrical and / or conical surfaces of the modular sections to be joined for centering. After joining the pole flanges of the connected modular shells, through holes for bolted (or hairpin or screw) connecting elements are made in them. After sealing the joint with the sealant, the pole flanges of 5 docked modular shells are pulled together and fastened together by bolted elements, or studs, or screw ones. The permanent connection of the pole metal flanges can be made by welding.

 If necessary, through the window (or hatch) in the wall of the centering sleeve, the cavity between the ovaloid bottoms of the joined shells is filled with an appropriate filler.

 If the design of the pressure vessel is sufficiently strong thin-walled coupling 8, it can be used as a structural and technological centering sleeve for centering abutting modular shells.

 The proposed method of manufacturing a pressure vessel simplifies and reduces the complexity of centering and docking of modular sections and allows the manufacture of large-capacity pressure vessels of almost any length (or height) on existing winding and autoclave or heat chamber equipment.

Sources of information
1. D.V. Rosato, K.S. Grove. Glass fiber winding. Method development, production, applications and design / Per. from English (Engineering, 1969. - 310 p. (See p. 28-29, Fig. 1.1).

 2. RU Pat. 2144644, F 17C 1/00, B 21D 51/24. Fiberglass high pressure cylinder and method of its manufacture.

Claims (17)

 1. A pressure vessel made of a composite material for transporting and storing liquids, liquefied gases and non-caking materials, comprising a cocoon housing formed by winding high-strength fibers fastened together with a polymeric binder, an internal sealing layer of gas-tight material and pole flanges sealed with hermetically sealed covers characterized in that the housing is made integral of at least two coaxially stacked cocoon-type modular casings made from a composite winding of material, and oval-shaped bottoms sealed tightly between themselves by polar flanges that form a hollow ring element of diametric stiffness (frame) in the joint zone of the joint body.  2. The pressure vessel according to claim 1, characterized in that the annular cavity of the frame is filled with elastic cushioning foam, hermetically glued to the outer surfaces of the joined bottoms and pole flanges with adhesive.  3. The pressure vessel according to claim 1, characterized in that the bottom surface of the hollow frame forms a cylindrical neck used to base and fasten the housing on the frame of the vehicle or tank container.  4. The pressure vessel according to any one of paragraphs. 1-3, characterized in that in the wall of the cylindrical neck of the hollow frame made structural and technological holes for the installation of equipment for monitoring the status of the contents of the product (substance) and / or ventilation devices or pressure relief valves.  5. The pressure vessel according to any one of paragraphs. 1-4, characterized in that the annular cavity is at least partially filled with annular banding coils of high-strength fibers, bonded to each other and glued to adjacent surfaces by a thermosetting polymer binder.  6. The pressure vessel according to any one of paragraphs. 1-5, characterized in that the annular cavity of the frame is closed externally with a thin-walled cylindrical sleeve made of a strong structural material, for example fiberglass, having strong overlapping adhesive joints with cylindrical surfaces of both joined modular shell casings.  7. The pressure vessel according to claim 6, characterized in that the closed cavity of the frame is filled with a light rigid cellular filler.  8. The pressure vessel according to claim 6 or 7, characterized in that the closed cavity of the frame is filled with a rigid filling polyurethane foam.  9. The pressure vessel according to claim 6 or 7, characterized in that the closed cavity of the frame is filled with rigid syntactic foam.  10. The pressure vessel according to claim 6 or 7, characterized in that the closed cavity of the frame is filled with foam concrete.  11. The pressure vessel according to claim 6 or 7, characterized in that the closed cavity of the frame is filled with powder or granular antifriction in the polymer matrix.  12. The pressure vessel according to any one of paragraphs. 1-11, characterized in that the coaxially docked modular shells of the composite housing have substantially different diametrical and / or longitudinal sizes and volumes.  13. The pressure vessel according to any one of paragraphs. 1-11, characterized in that one of the docked modular shells has a conical shape between its oval shaped bottoms.  14. A method of manufacturing a pressure vessel, including the manufacture of modular housing elements from composite material and their subsequent assembly, characterized in that at least two modular sections are manufactured - cocoon shells from a winding composite material with an internal sealing layer and pole flanges , insert them into a cylindrical centering sleeve (one on the one hand, the other on the other), the inner diameter of the centering cylindrical channel of which corresponds to the outer diameter of the cylindrical the surface of the modular sections, thus ensuring their alignment; and then, moving the sections towards each other, they join the necks of the pole flanges and connect them to each other, ensuring the strength and tightness of the connection in any known manner.  15. A method of manufacturing a pressure vessel according to claim 14, characterized in that after joining the docked modular sections, the cavity between the docked and fastened bottoms is filled through the hole in the wall of the cylindrical sleeve with a filling composition of rigid or flexible polyurethane foam and foamed in a closed mold-forming volume of the sleeve.  16. A method of manufacturing a pressure vessel according to any one of paragraphs. 14 and 15, characterized in that a thin-walled coupling, for example, of winding fiberglass, is used as the centering cylindrical sleeve, which is a structural member of the pressure vessel assembly body that fastens the cylindrical parts of the joined modular sections to one another, and glued to them in the annular sections of the telescopic overlap, for example, using foaming glue cold curing.  17. A method of manufacturing a pressure vessel according to claim 16, characterized in that a technological hole is made in the wall of the thin-walled cylindrical sleeve of the composite housing and the closed cavity of the frame is filled with a light or flame-retardant filler through it.

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