Novel sealing heat preservation pressing plate structure of cold insulation box outlet pipe

Abstract

The invention discloses a novel sealing heat preservation pressing plate structure of an outlet pipe of a cold insulation box, and relates to the related technical field of air separation, the novel sealing heat preservation pressing plate structure comprises the cold box, a hollow cylindrical metal sleeve is fixedly welded to a shell of the cold box, and a metal flange is welded to the end, away from the cold box, of the metal sleeve. The double guarantee of efficient heat preservation and reliable sealing is achieved, and the requirements of extremely cold working conditions are met; wherein the metal sleeve and the double-layer modified phenolic aldehyde bakelite plate form a low-heat-conduction barrier, an annular gap is filled with a foaming agent for sealing holes, an end face gap is filled with a non-metal cushion, cold conduction is blocked through a triple structure, and the cold loss rate is greatly reduced; the perfluororubber low-temperature O-shaped sealing ring is in interference fit with the pipeline and is matched with the axial sealing of the non-metal cushion, so that moisture permeation and gas leakage are prevented; the elastic washer absorbs cold contraction deformation, an assembly and cold contraction gap is reserved, embrittlement or sealing failure of components at low temperature is avoided, long-term stable operation of the cold insulation box is guaranteed, and the cold insulation box is adaptive to extremely cold working conditions in the air separation industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of space division, in particular to a sealing and heat preservation pressing plate structure of a new cold insulation tank lead-out pipe. BACKGROUND

[0002] In the air separation industry, the cold insulation tank (referred to as "cold tank") is the core low-temperature sealed tank of the air separation equipment, which is responsible for wrapping the low-temperature components such as rectification tower and plate heat exchanger, and maintaining the extremely cold working condition of about -196℃ through heat insulation design to ensure the stable and efficient air liquefaction and gas separation. When the cold tank is running, low-temperature medium needs to be transported through low-temperature pipes penetrating the tank wall, and the connection between the pipe and the tank wall is the weak link of heat insulation and sealing. It is necessary to block the conduction of cold energy to avoid energy consumption rising, and to prevent external moisture from penetrating to damage the equipment. Therefore, the pressing plate structure at the connection is crucial to the stable operation of the air separation equipment.

[0003] At present, there are mainly two types of pressing plate structures in the industry: one is the traditional metal pressing plate structure (see the attached drawings Figure 1 ), which is composed of a metal pressing plate, a non-metal sealing gasket and a fastener. The metal pressing plate fixes the pipe, and the structure is simple and has strong bearing capacity, but the metal has high thermal conductivity. The other type is a bakelite sleeve composite structure (see the attached drawings Figure 2 ). A modified phenolic bakelite plate with low thermal conductivity is used as a sleeve to cover the pipe, and a metal flange is used for fixation to weaken the conduction of cold energy, which is suitable for scenes with high requirements for cold loss control.

[0004] Both types of structures have obvious defects. The traditional metal pressing plate has strong thermal conductivity, which easily forms a "thermal bridge", resulting in cold energy loss (cold loss rate ≥ 15%), and also causes local low-temperature condensation and icing on the tank wall, which easily leads to deformation and cracking in the long term. Although the bakelite sleeve alleviates the cold loss, there is an assembly gap between the single-layer bakelite plate and the pipe, which causes sealing failure. Dry gas in the cold tank is easy to leak, and external moisture is easy to penetrate, which leads to frosting and corrosion of the equipment. Moisture icing also causes the sleeve to deform, which aggravates the failure. Moreover, the fasteners and sleeves of both types of structures are easy to be brittle or cold-shrunk at low temperature, which is difficult to meet the long-term stable operation requirements of the air separation equipment. SUMMARY

[0005] Based on this, the purpose of the present application is to provide a sealing and heat preservation pressing plate structure of a new cold insulation tank lead-out pipe to solve the technical problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a sealing and heat preservation pressing plate structure of a new cold insulation tank lead-out pipe, comprising a cold tank, a hollow cylindrical metal sleeve is welded and fixed on the cold tank shell, a metal flange is welded at the end of the metal sleeve away from the cold tank, a low-temperature liquid pipe is arranged in the metal sleeve, and the inner hole diameter of the metal sleeve is greater than the outer diameter of the low-temperature liquid pipe. The metal flange is sequentially provided with an inner rubber wood plate, a non-metallic soft pad and an outer rubber wood plate, the inner rubber wood plate and the outer rubber wood plate are both provided with a central through hole coaxially aligned with the inner hole of the metal sleeve; the end face of the outer rubber wood plate close to the inner rubber wood plate is provided with an annular groove, and a low-temperature O-shaped sealing ring is embedded in the annular groove and is in interference fit with the low-temperature liquid pipeline. The outer rubber wood plate, the inner rubber wood plate and the non-metallic soft pad are connected and fixed with the metal flange through a fixing assembly, and the annular gap between the metal sleeve, the inner rubber wood plate and the low-temperature liquid pipeline is filled with a foaming agent.

[0007] By adopting the above technical scheme, the double-layer rubber wood plate blocks cold, the low-temperature O-shaped sealing ring is radially sealed, the foaming agent fills the gap and strongly keeps warm, the fixing assembly connects the components, prevents cold damage and moisture penetration, adapts to extremely cold working conditions, and solves the pain points of traditional structures.

[0008] Further, the inner rubber wood plate and the outer rubber wood plate are parallelly arranged and are both circular plate structures, both of which are modified phenolic rubber wood plates with a thermal conductivity coefficient of ≤0.03 W / (m·K) and no brittle fracture phenomenon at-196℃ low-temperature environment.

[0009] By adopting the above technical scheme, the parallel circular structure is uniformly stressed, cold shrinkage damage is avoided, and service life is prolonged to keep warm and stable.

[0010] Further, the non-metallic soft pad is in an annular structure and is made of polytetrafluoroethylene modified material with a low-temperature resistance range of-200℃ to normal temperature, the inner diameter of the non-metallic soft pad is consistent with the inner diameter of the sealing surface of the metal flange, and the outer diameter of the non-metallic soft pad is matched with the outer diameter of the inner rubber wood plate, so that the gap between the inner rubber wood plate and the metal flange can be filled by axial extrusion deformation.

[0011] By adopting the above technical scheme, cold leakage is blocked and vibration is slowed down, rigid contact damage to components is avoided, and the sealing protection effect is improved.

[0012] Further, the low-temperature O-shaped sealing ring is made of perfluorinated rubber material and is adapted to a temperature range of-196℃ to normal temperature, the cross-sectional size of the annular groove is in interference fit with the cross-sectional size of the low-temperature O-shaped sealing ring, so as to ensure that the sealing ring is tightly fitted with the inner wall of the groove.

[0013] By adopting the above technical scheme, radial sealing is reliable, and frost corrosion of equipment is prevented.

[0014] Further, the fixing assembly comprises a bolt, a nut and an elastic washer, the metal flange is uniformly provided with a threaded hole in the circumference direction, the outer layer of rubber wood board, the inner layer of rubber wood board and the non-metallic soft pad are provided with a through assembly hole corresponding to the position of the threaded hole, the bolt is sequentially threaded through the assembly hole and is screwed with the threaded hole, and the elastic washer is a stainless steel wave washer which can absorb a cold shrinkage deformation of ≤5mm to offset the axial stress under low temperature working conditions.

[0015] By adopting the technical scheme, the axial stress is offset, the uniform compression force is applied to the circumferential hole, the components are tightly attached, and the structural stability is improved.

[0016] Further, the foaming agent is a low-temperature polyurethane foaming material, and after foaming, a dense closed pore structure is formed, and is tightly bonded with the inner wall of the metal sleeve, the inner wall of the central through hole of the inner layer of rubber wood board and the outer wall of the low-temperature liquid pipeline, without air bubble residue.

[0017] By adopting the technical scheme, the annular gap is filled, the structural integrity is enhanced, air convection cold loss is avoided, and the heat preservation effect is improved to adapt to the heat insulation demand.

[0018] Further, the diameter of the central through hole is slightly larger than the outer diameter of the low-temperature liquid pipeline, and a cold shrinkage compensation gap is reserved; the metal sleeve is made of 304 stainless steel material, and the metal flange is made of carbon steel material, both of which have low-temperature corrosion resistance.

[0019] By adopting the technical scheme, the pipeline cold shrinkage is adapted, and the extrusion damage is avoided; the sleeve flange is made of corrosion-resistant material, which prevents low-temperature rust and prolongs the service life to ensure long-term stable operation of the structure.

[0020] In summary, the present application mainly has the following beneficial effects: The present application realizes efficient heat preservation and reliable sealing double protection, and adapts to the demand of extremely cold working conditions; wherein, the metal sleeve and the double-layer modified phenolic rubber wood board form a low-thermal-conductivity barrier, the annular gap is filled with a dense closed pore foaming agent, and the non-metallic soft pad fills the end surface gap, the three structures block the cold conduction, and the cold loss rate is greatly reduced; the perfluorinated rubber low-temperature O-shaped sealing ring is tightly attached to the pipeline with interference, and the axial sealing of the non-metallic soft pad prevents moisture from penetrating and gas from leaking; the elastic washer absorbs the cold shrinkage deformation, and a cold shrinkage gap is reserved for assembly, which avoids the brittle fracture or sealing failure of the components under low temperature, and ensures the long-term stable operation of the cold storage tank, and adapts to the extremely cold working conditions of the air separation industry. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of the existing pressing plate structure; Figure 2 is a schematic view of the existing rubber wood board sleeve composite structure; Figure 3 is a schematic view of the overall structure of the present application; Figure 4 It is a schematic diagram of the overall structure of the application after being cut open; Figure 5 It is a schematic diagram of the overall structure of the application after being cut open; Figure 6 It is a schematic diagram of the overall structure of the application after being cut open; Figure 4 It is a schematic diagram of the overall structure of the application after being cut open.

[0022] In the figure: 1, cold box; 2, metal sleeve; 3, low-temperature liquid pipeline; 4, metal flange; 5, inner layer of bakelite plate; 6, outer layer of bakelite plate; 7, center through hole; 8, non-metallic soft pad; 9, low-temperature O-shaped sealing ring; 10, annular groove; 11, foaming agent; 12, fixing assembly. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. The embodiments described below with reference to the drawings are exemplary and are only used to explain the application, and cannot be understood as a limitation of the application.

[0024] The embodiments of the application will be described below according to the overall structure of the application.

[0025] A new sealing and heat-insulating pressing plate structure of a cold box lead pipe, as shown in Figure 3 - Figure 6 The sealing and heat-insulating pressing plate structure of the cold box lead pipe includes cold box 1, metal sleeve 2, low-temperature liquid pipeline 3, metal flange 4, inner layer of bakelite plate 5, outer layer of bakelite plate 6, center through hole 7, non-metallic soft pad 8, low-temperature O-shaped sealing ring 9, annular groove 10, foaming agent 11, and fixing assembly 12. The metal sleeve 2 is welded and fixed on the shell of the cold box 1, and provides a passage for the low-temperature liquid pipeline 3 to pass out of the cold box 1. The metal sleeve 2 is a hollow cylindrical structure, is made of 304 stainless steel, is resistant to low-temperature corrosion and has sufficient rigidity, has an inner hole diameter greater than the outer diameter of the low-temperature liquid pipeline 3, and has an annular gap reserved for filling the foaming agent 11. The metal flange 4 made of carbon steel is welded to the end of the metal sleeve 2 away from the cold box 1, has screw holes evenly arranged in the circumferential direction, and is used to cooperate with the fixing assembly 12 to realize the connection and fixation of the components.

[0026] The low-temperature liquid pipeline 3 is arranged in the metal sleeve 2 and is used to transport low-temperature medium. The low-temperature liquid pipeline 3 has an outer diameter less than the inner hole diameter of the metal sleeve 2 and the diameter of the center through hole 7, and has a reserved assembly and cold shrinkage compensation gap.

[0027] The inner layer of rubber wood plate 5 and the outer layer of rubber wood plate 6 are arranged in parallel, both are circular plate structure, using modified phenolic resin wood plate, the thermal conductivity is less than or equal to 0.03 W / (m·K), there is no brittle fracture phenomenon in-196 ℃ low temperature environment; Both are provided with a center through hole 7, the center through hole 7 is coaxially aligned with the inner hole of the metal sleeve 2, the diameter is slightly larger than the outer diameter of the low temperature liquid pipeline 3, and is suitable for assembly and cold shrinkage demand; The inner layer of rubber wood plate 5 is close to the low temperature environment inside the cold box 1, and the outer layer of rubber wood plate 6 is located outside the cold box 1, and the two form a double layer low thermal conductivity barrier to block the cold conduction.

[0028] The non-metallic soft pad 8 is annular structure, using polytetrafluoroethylene modified material, the low temperature resistance range is-200 ℃ to normal temperature, and is arranged between the end surface of the inner layer of rubber wood plate 5 and the metal flange 4; The inner diameter is consistent with the inner diameter of the sealing surface of the metal flange 4, and the outer diameter is matched with the outer diameter of the inner layer of rubber wood plate 5, which can fill the gap between the inner layer of rubber wood plate 5 and the metal flange 4 through axial extrusion deformation, avoid the leakage of cold through the gap, and buffer the vibration transmission.

[0029] The low temperature O-shaped sealing ring 9 is made of perfluorinated rubber material, which is suitable for the temperature range of-196 ℃ to normal temperature, and is embedded in the annular groove 10 arranged on the end surface of the outer layer of rubber wood plate 6 close to the inner layer of rubber wood plate 5; The cross-sectional size of the annular groove 10 and the cross-sectional size of the low temperature O-shaped sealing ring 9 are interference fit, which ensures that the sealing ring is closely combined with the inner wall of the groove; The inner diameter of the low temperature O-shaped sealing ring 9 is interference fit with the outer diameter of the low temperature liquid pipeline 3, forming radial sealing, blocking the outside air and moisture into the cold box 1.

[0030] The foaming agent 11 is a low temperature polyurethane foaming material, which is filled in the annular gap between the metal sleeve 2, the inner layer of rubber wood plate 5 and the low temperature liquid pipeline 3; After foaming, it forms a dense closed pore structure without bubble residue, and is tightly bonded with the inner wall of the metal sleeve 2, the inner wall of the center through hole 7 of the inner layer of rubber wood plate 5 and the outer wall of the low temperature liquid pipeline 3, forming an integrated heat preservation sealing layer, further blocking the cold conduction path.

[0031] The fixed assembly 12 includes bolts, nuts and elastic washers, the outer layer of rubber wood plate 6, the inner layer of rubber wood plate 5 and the non-metallic soft pad 8 are provided with through assembly holes corresponding to the positions of the threaded holes of the metal flange 4; The bolt passes through the assembly holes of the outer layer of rubber wood plate 6, the inner layer of rubber wood plate 5 and the non-metallic soft pad 8 in sequence, and is screwed with the threaded hole of the metal flange 4, and the axial compression and fixation of each component are realized by locking with the nut; The elastic washer is a stainless steel wave washer, which can absorb cold shrinkage deformation of less than or equal to 5 mm, and is used to offset the axial stress of each component under low temperature working condition, so as to avoid the rigid compression leading to the cracking of rubber wood plate or the sealing failure of sealing ring.

[0032] Through the cooperation of the above-mentioned components, during assembly, the cold box 1 shell is welded and fixed to the hollow cylindrical metal sleeve 2, the end of the metal sleeve 2 away from the cold box 1 is welded to the metal flange 4, and a stable passage for the low-temperature liquid pipeline 3 to pass out of the cold box 1 is formed; the low-temperature liquid pipeline 3 is arranged in the metal sleeve 2, the inner hole diameter of the metal sleeve 2 is greater than the outer diameter of the low-temperature liquid pipeline 3, and an annular gap is reserved for filling the heat preservation material; The metal flange 4 is sequentially assembled with the inner layer rubber wood plate 5, the non-metallic soft pad 8 and the outer layer rubber wood plate 6 on one side, all of which are provided with a central through hole 7 coaxially aligned with the inner hole of the metal sleeve 2, and the diameter of the central through hole 7 is slightly larger than the outer diameter of the low-temperature liquid pipeline 3, leaving a cold shrinkage compensation space for assembly; the low-temperature O-shaped sealing ring 9 is embedded in the annular groove 10 of the outer layer rubber wood plate 6, and is in interference fit with the low-temperature liquid pipeline 3; the fixing assembly 12 (screw, nut and elastic washer) passes through the assembly holes of the outer layer rubber wood plate 6, the inner layer rubber wood plate 5 and the non-metallic soft pad 8 in sequence, and is screwed and locked with the threaded holes of the metal flange 4, so as to realize the axial compression and fixation of the components; During use, in the extremely cold environment of-196℃ in the cold box 1, the cold energy of the low-temperature liquid pipeline 3 is blocked by multiple structures to avoid the formation of a "heat conduction bridge"; In this process, since the inner layer rubber wood plate 5 and the outer layer rubber wood plate 6 are both modified phenolic rubber wood plates with a heat conductivity coefficient ≤0.03 W / (m·K) and no brittle fracture at low temperature, a double-layer low-heat-conduction barrier is formed to directly weaken the cold energy conduction path; at the same time, the annular gap between the metal sleeve 2, the inner layer rubber wood plate 5 and the low-temperature liquid pipeline 3 is filled with low-temperature polyurethane foaming agent 11, which forms a dense closed pore structure after foaming, tightly bonds with each contact surface, and has no air bubble residue, completely blocking the cold conduction caused by direct contact between metal and pipeline; and the non-metallic soft pad 8 fills the micro gap between the inner layer rubber wood plate 5 and the metal flange 4 by axial extrusion deformation, eliminates the air convection in the gap, and further reduces the cold loss caused by convective heat transfer; the triple insulation structure cooperates to reduce the cold energy conduction loss rate to ≤3%; At the same time, the low-temperature O-shaped sealing ring 9 is made of perfluorinated rubber material, which is suitable for-196℃ to room temperature range, and is in interference fit with the low-temperature liquid pipeline 3, and at the same time, it is in interference fit with the annular groove 10, tightly adheres to the inner wall of the groove, blocks the infiltration of external moisture and air along the pipeline surface into the cold box 1, and prevents icing at low temperature from damaging the heat insulation layer; the inner diameter of the non-metallic soft pad 8 is consistent with the inner diameter of the sealing surface of the metal flange 4, and the outer diameter matches the outer diameter of the inner layer rubber wood plate 5, which fills the end gap between the inner layer rubber wood plate 5 and the metal flange 4 by extrusion deformation, blocks the gas leakage of the axial gap, and at the same time avoids the leakage of dry gas in the cold box 1, ensuring the stability of the heat insulation environment in the cold box 1; Under low temperature working condition, each component will produce cold shrinkage deformation, the stainless steel wave elastic washer in the fixed assembly 12 can absorb the cold shrinkage deformation of ≤5mm, offset the axial stress, avoid rigid compression leading to the cracking of bakelite board or low temperature O-shaped sealing ring 9 sealing failure; at the same time, the cold shrinkage compensation gap reserved in the center through hole 7, the flexible characteristics of the foaming agent 11 can adapt to the cold shrinkage deformation of the low temperature liquid pipeline 3, ensure that each component is connected stably in long-term operation, and the heat preservation and sealing performance is not attenuated.

[0033] Although the embodiments of the present application have been shown and described, the specific embodiments are merely illustrative of the present application, and are not intended to limit the present application, and the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner, and those skilled in the art can make modifications, replacements and variations of the embodiments without creative contribution after reading the specification, as long as they are within the scope of the claims of the present application.

Claims

1. A new type of sealing and heat-insulating pressing plate structure for a lead-out pipe of a cold storage tank, characterized in that, The cold box (1) is provided with a hollow cylindrical metal sleeve (2) welded on the shell, the metal sleeve (2) is welded with a metal flange (4) at the end away from the cold box (1), and a low-temperature liquid pipeline (3) is arranged in the metal sleeve (2), and the inner diameter of the metal sleeve (2) is larger than the outer diameter of the low-temperature liquid pipeline (3); The metal flange (4) is provided with an inner layer of rubber wood board (5), a non-metallic soft pad (8) and an outer layer of rubber wood board (6) in sequence on one side, the inner layer of rubber wood board (5) and the outer layer of rubber wood board (6) are provided with a central through hole (7), and the central through hole (7) is coaxially aligned with the inner hole of the metal sleeve (2); the end face of the outer layer of rubber wood board (6) close to the inner layer of rubber wood board (5) is provided with an annular groove (10), and the annular groove (10) is embedded with a low-temperature O-shaped sealing ring (9) which is in interference fit with the low-temperature liquid pipeline (3); The outer layer of rubber wood board (6), the inner layer of rubber wood board (5) and the non-metallic soft pad (8) are connected and fixed with the metal flange (4) through a fixing assembly (12), and the annular gap between the metal sleeve (2), the inner layer of rubber wood board (5) and the low-temperature liquid pipeline (3) is filled with a foaming agent (11).

2. The novel sealing and insulating pressure plate structure of the cold box outlet pipe according to claim 1, characterized in that, The inner layer of rubber wood board (5) and the outer layer of rubber wood board (6) are arranged in parallel and are both circular plate structures, both of which are modified phenolic wood boards with a thermal conductivity of less than or equal to 0.03 W / (m·K) and no brittle fracture at a low temperature of-196℃.

3. The novel sealing and insulating press plate structure of the cold box outlet pipe according to claim 1, characterized in that, The non-metallic soft pad (8) is in the form of a ring and is made of polytetrafluoroethylene modified material, has a low-temperature resistance range of-200℃ to normal temperature, has an inner diameter consistent with the inner diameter of the sealing surface of the metal flange (4) and an outer diameter matched with the outer diameter of the inner layer of rubber wood board (5), and can fill the gap between the inner layer of rubber wood board (5) and the metal flange (4) through axial extrusion deformation.

4. The novel sealing and insulating press plate structure of the cold box outlet pipe according to claim 1, characterized in that, The low-temperature O-shaped sealing ring (9) is made of perfluorinated rubber material and is suitable for a temperature range of-196℃ to normal temperature, the cross-sectional size of the annular groove (10) is in interference fit with the cross-sectional size of the low-temperature O-shaped sealing ring (9), and the sealing ring is tightly fitted with the inner wall of the groove.

5. The novel sealing and insulating press plate structure of the cold box outlet pipe according to claim 1, characterized in that, The fixing assembly (12) includes a bolt, a nut and an elastic washer, the metal flange (4) is uniformly provided with threaded holes in the circumferential direction, the outer layer of rubber wood board (6), the inner layer of rubber wood board (5) and the non-metallic soft pad (8) are provided with through assembly holes corresponding to the positions of the threaded holes, the bolt is screwed with the threaded holes in sequence after passing through the assembly holes, and the elastic washer is a stainless steel wave washer which can absorb a cold shrinkage deformation of less than or equal to 5mm to offset the axial stress under low-temperature working conditions.

6. The novel sealing and insulating press plate structure of the cold box outlet pipe according to claim 1, characterized in that, The foaming agent (11) is a low-temperature polyurethane foaming material, forms a dense closed-cell structure after foaming, and is tightly bonded with the inner wall of the metal sleeve (2), the inner wall of the central through hole (7) of the inner layer of rubber wood board (5) and the outer wall of the low-temperature liquid pipeline (3), and has no bubble residue.

7. The novel sealing and insulating press plate structure of the cold box outlet pipe according to claim 1, characterized in that, The central through hole (7) has a diameter slightly larger than the outer diameter of the low-temperature liquid pipeline (3) to reserve assembly and cold shrinkage compensation gaps; the metal sleeve (2) is made of 304 stainless steel material, and the metal flange (4) is made of carbon steel material, both of which have low-temperature corrosion resistance.

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