Integrated pouring type PIR cold insulation pipe and manufacturing method thereof

Abstract

The invention discloses an integrated pouring type PIR cold insulation pipe and a manufacturing method thereof, and relates to the technical field of cold insulation pipes. The high-density PIR cold insulation steel pipe comprises a working steel pipe body, two high-density PIR baffle rings are bonded to the outer layer of the working steel pipe body, the outer surfaces of the high-density PIR baffle rings are wrapped with glass fiber isolation layers, the outer surfaces of the glass fiber isolation layers are wrapped with damp-proof layers, and PIR cold insulation layers are arranged on the outer surfaces of the damp-proof layers. A high-density polyethylene protective layer is wound on the outer surface of the PIR cold insulation layer, and a glass fiber reinforced plastic protective layer is arranged on the outer surface of the high-density polyethylene protective layer. The novel PIR cold insulation pipe is manufactured by adopting an integrated process, has better compressive strength and ultralow heat conductivity coefficient, can remarkably reduce medium conduction consumption, realizes factory prefabrication, strictly inspects and detects performance indexes of raw materials and finished products, realizes quality control in the whole production process, and enables materials of all layers to be combined more tightly.

Description

Technical Field

[0001] The invention relates to the technical field of cold-insulating pipes, and in particular to an integrated cast PIR cold-insulating pipe and a manufacturing method thereof. Background Art

[0002] During the transportation of the pipeline system, the cold insulation pipe can keep the pipeline cold and warm, prevent the fluid or gas in the pipeline system from losing heat energy, improve energy efficiency, and ensure the stability and safety of equipment operation.

[0003] The patent with the authorization announcement number CN204805755U discloses a PIR composite cryogenic prefabricated insulation pipe, including an inner pipe for circulating substances, a protective layer coaxially sleeved on the outside of the inner pipe, a PIR layer between the inner pipe and the protective layer, and an aluminum foil reflective layer between the PIR layer and the inner pipe. However, the patent also has the following defects: the pipeline adopts a single-layer PIR layer, and the insulation effect is limited. At the same time, the protective layer is made of stainless steel, color steel or galvanized sheet, resulting in a large overall weight of the pipeline, poor corrosion resistance, and easy scratching on the surface. At the same time, the on-site splicing construction progress of the prefabricated shell of the existing cold-insulating pipe is slow, and the influence of human construction factors is large. The connection gaps between individual shells are not properly handled, resulting in cold exposure and cold penetration, and on-site management is difficult. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and provide an integrated cast PIR cold insulation pipe and a manufacturing method thereof.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: An integrated cast PIR cold insulation pipe comprises a working steel pipe, the outer layer of which is bonded with two high-density PIR baffle rings, the outer surface of which is wrapped with a glass fiber insulation layer, the outer surface of which is wrapped with a moisture-proof layer, the outer surface of which is provided with a PIR cold insulation layer, the outer surface of which is wrapped with a high-density polyethylene protective layer, and the outer surface of which is provided with a glass fiber reinforced plastic protective layer; The two high-density PIR retaining rings are bonded to the working steel pipe using a cryogenic adhesive, and the interface positions of the two high-density PIR retaining rings are sealed with a cryogenic sealant; The glass fiber isolation layer is woven in a transverse and longitudinal interlaced manner.

[0006] Furthermore, the high-density PIR retaining ring is a prefabricated part.

[0007] Furthermore, the moisture-proof layer is made of a PAP aluminum foil composite film and is annularly wound on the outer surface of the glass fiber isolation layer.

[0008] Furthermore, two ends of the PIR cold insulation layer are arranged in a stepped manner.

[0009] Furthermore, the fiberglass protective layer is composed of an inner layer of glass fiber pre-impregnated cloth and an outer layer of epoxy resin.

[0010] Furthermore, a photoinitiator is added inside the epoxy resin.

[0011] The manufacturing method of the integrated cast PIR cold insulation pipe comprises the following steps: S1. Pipe selection: Pre-treat the outer surface of the working steel pipe to remove oil, dust, and check the appearance; S2. Prefabrication and installation of high-density PIR retaining rings: take material A, which is polyether, polyester polyol and an auxiliary agent, wherein the auxiliary agent is one or more of a foaming agent, a foam stabilizer, a catalyst and a flame retardant, take material B, which is isocyanate, and then mix material A with material B, and then inject the mixture into the retaining ring mold through a polyurethane foaming machine, remove the mold after it is fully matured, take out the high-density PIR retaining ring, install two high-density PIR retaining rings on the outer surface of the working steel pipe, fix them with a cryogenic adhesive, and seal the interface positions of the two high-density PIR retaining rings with a cryogenic sealant; S3. Production of glass fiber insulation layer: According to the size of the steel pipe, cut glass fiber needle felt of appropriate width and wrap it on the outer wall of the steel pipe, weave it horizontally and vertically to form a glass fiber insulation layer; S4. Moisture-proof layer production: Cut the PAP aluminum foil composite film of appropriate width and wrap it in a ring around the glass fiber isolation layer to form a moisture-proof layer. The PAP film should be tightly wrapped without gaps and evenly overlapped. The overlap should be sealed and fixed with aluminum foil tape to ensure airtightness. S5, PIR cold insulation layer production: spray a polypropylene coating on the inner wall of the cold insulation layer mold, put the steel pipe completed in S4 on the mold, merge and lock the cold insulation layer mold, and then use an infrared temperature control device to preheat the steel pipe from the inside to ensure that the surface temperature of the pipe body is 25-30℃, and then use an electric fan to preheat the mold cavity to ensure that the temperature inside the cavity is 25-30℃. Use a polyurethane foaming machine to mix material A and material B and pour them into the mold cavity. After pouring, use a digital temperature control insulation blanket outside the mold to insulate it to promote full maturation of the combined material and ensure the PIR foaming effect. After standing for a period of time, the mold is opened to obtain an integrated PIR cold insulation pipe; S6. Production of high-density polyethylene protective layer: Place the PIR cold-insulation pipe on the transmission line and run it in a spiral. The extruder extrude a certain thickness of molten polyethylene sheet and wrap it around the PIR cold-insulation pipe. As the PIR cold-insulation pipe continues to rotate and move forward, the extruder continuously extrude the molten polyethylene sheet and wrap it on the surface of the polyurethane layer according to the controlled pitch. After cooling, the polyethylene outer sheath tightly wraps the PIR cold-insulation pipe, completing the production of the high-density polyethylene protective layer. S7. Preparation of FRP protective layer: Place the cold-keeping pipe prepared in step S6 on the workbench and rotate it at a constant speed. Then, automatically wrap the glass fiber pre-impregnated cloth around the cold-keeping pipe and evenly apply epoxy resin with photoinitiator. After all-round irradiation with ultraviolet light, cure it to form a FRP protective layer.

[0012] The beneficial effects of the present invention are as follows: 1. The pipeline of the present invention adds a high-density PIR retaining ring to the inner layer. This design effectively reduces the heat conduction of the cold insulation layer, thereby improving the overall thermal insulation effect. The high-density characteristics of the retaining ring enhance the thermal insulation performance of the PIR cold insulation layer, so that the temperature of the fluid in the pipeline remains more stable and the heat loss is smaller.

[0013] 2. The PIR cold-insulation pipe of the present invention adds a special moisture-proof layer between the cold-insulation layer and the outer protective layer, which can effectively prevent moisture penetration and avoid the reduction of thermal insulation performance and material degradation caused by moisture penetration in traditional PIR cold-insulation pipes.

[0014] 3. The outer layer of the PIR cold-insulating pipe of the present invention adopts a glass fiber reinforced plastic protective layer. Compared with the traditional metal outer layer, the glass fiber reinforced plastic material provides stronger impact resistance, tensile resistance and external pressure resistance. The glass fiber reinforced plastic material also has strong corrosion resistance and can effectively resist the damage to the pipeline caused by chemicals, acid and alkali substances and climate change. The use of a high-density polyethylene protective layer further enhances the wear resistance and weather resistance of the pipeline, and can resist the harsh conditions of the external environment, such as ultraviolet radiation, temperature fluctuations, etc.

[0015] 4. The overall structure of the PIR cold-keeping pipe of the present invention is optimized, so that the combination of each layer of material is tighter, the pipe is more stable and resistant to deformation, and the design and matching of each layer of material can effectively avoid the problems of structural looseness and material peeling that may occur in traditional cold-keeping pipes during long-term use.

[0016] 5. The PIR cold-keeping pipe of the present invention is made by an integrated process, has better compressive strength and ultra-low thermal conductivity, can significantly reduce medium conduction consumption, and realizes factory prefabrication. The raw materials and finished product performance indicators are strictly inspected and tested to achieve quality control of the entire production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the integrated cast PIR cold insulation pipe of the present invention; Figure 2 This is a cross-sectional schematic diagram of the integrated cast PIR cold insulation pipe of the present invention; Figure 3 It is a schematic diagram of the structure of the retaining ring mold of the present invention; Figure 4 It is a schematic diagram of the cold-insulation layer mold structure of the present invention.

[0018] Figure numerals: 1. working steel pipe; 2. high-density PIR retaining ring; 21. retaining ring mold; 3. glass fiber isolation layer; 4. moisture-proof layer; 5. PIR cold insulation layer; 51. cold insulation layer mold; 6. high-density polyethylene protective layer; 7. fiberglass protective layer. DETAILED DESCRIPTION

[0019] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] Embodiment 1, as Figure 1-Figure 4 As shown, the integrated cast PIR cold insulation pipe includes a working steel pipe 1, the outer layer of the working steel pipe 1 is bonded with two high-density PIR retaining rings 2, the outer surface of the high-density PIR retaining ring 2 is wrapped with a glass fiber isolation layer 3, the outer surface of the glass fiber isolation layer 3 is wrapped with a moisture-proof layer 4, the outer surface of the moisture-proof layer 4 is provided with a PIR cold insulation layer 5, the outer surface of the PIR cold insulation layer 5 is wrapped with a high-density polyethylene protective layer 6, and the outer surface of the high-density polyethylene protective layer 6 is provided with a glass fiber reinforced plastic protective layer 7.

[0021] High-density polyethylene as a protective layer has the following advantages: (1) The high-density polyethylene protective layer 6 has excellent corrosion resistance and can effectively resist the erosion of chemical substances such as acids, alkalis, and salts; (2) The high-density polyethylene protective layer 6 has a high density and excellent waterproof performance. It can be used in humid environments such as rain and moisture to effectively prevent items from getting damp; (3) The high-density polyethylene protective layer 6 has excellent wear resistance and can effectively protect items from wear, scratches, etc.; (4) The high-density polyethylene protective layer 6 has good chemical stability and can remain stable in various chemical environments; (5) The high-density polyethylene protective layer 6 has high mechanical strength and can withstand certain impacts and pressures. It is not easy to be damaged or deformed; (6) The high-density polyethylene protective layer 6 has good climate adaptability and can work stably under various climatic conditions; (7) The high-density polyethylene protective layer 6 has a long service life and can maintain its performance and functions for a long time.

[0022] Embodiment 2, based on the above embodiment, further includes that the high-density PIR retaining ring 2 is a prefabricated part, which is easy to install.

[0023] Furthermore, the two high-density PIR retaining rings 2 are bonded to the working steel pipe 1 with a cryogenic adhesive, and the interface positions of the two high-density PIR retaining rings 2 are sealed with a cryogenic sealant, which can maintain its sealing performance in an extremely low temperature environment and has high installation sealing performance.

[0024] Embodiment 3, based on the above embodiment, further includes that the glass fiber isolation layer 3 is woven in a transverse and longitudinal direction to ensure that there are no gaps and the layer does not protrude beyond the outer surface.

[0025] Furthermore, the moisture-proof layer 4 is made of a PAP aluminum foil composite film, and is annularly wound on the outer surface of the glass fiber isolation layer 3. The PAP aluminum foil composite film improves the overall physical strength and barrier properties by combining aluminum foil with paper and plastic film. The paper layer provides a certain strength and rigidity, and the plastic layer helps to increase the barrier capacity for moisture, further improving the moisture-proof effect.

[0026] Embodiment 4, based on the above embodiment, further includes that two ends of the PIR cold insulation layer 5 are arranged in a stepped manner to ensure that the PIR cold insulation layer 5 and the patching material are overlapped with each other to reduce cold loss.

[0027] Embodiment 5, based on the above embodiment, further includes that the glass fiber reinforced plastic protective layer 7 is composed of an inner layer of glass fiber pre-impregnated cloth and an outer layer of epoxy resin.

[0028] Furthermore, a photoinitiator is added inside the epoxy resin.

[0029] The performance advantages of the FRP protective layer 7 are as follows: (1) The FRP protective layer 7 is composed of glass fiber and resin, and has high strength and corrosion resistance. It can effectively prevent the corrosion of chemical substances on the protected object, and has good waterproof performance, which can prevent moisture from penetrating into the protected object, thereby extending its service life; (2) The FRP protective layer 7 has high strength and rigidity, which can effectively enhance the compressive and tensile mechanical properties of the protected object, which makes the FRP protective layer 7 perform well when subjected to various external loads, ensuring the structural stability of the protected object; (3) The FRP protective layer 7 has excellent anti-ultraviolet effect. Through scientific formula and process control, a dense protective layer is formed on the surface of the FRP, which can effectively block ultraviolet radiation and reduce the destructive effect of ultraviolet rays on the material, thereby extending the service life.

[0030] Embodiment 6, the manufacturing method of the integrated cast PIR cold insulation pipe comprises the following steps: S1. Pipe selection: pre-treat the outer surface of the working steel pipe 1 to remove oil, dust, and check the appearance; S2, prefabrication and installation of high-density PIR retaining ring 2: take material A, material A is polyether, polyester polyol and auxiliary agent, the auxiliary agent is one or more of foaming agent, foam stabilizer, catalyst and flame retardant, take material B, material B is isocyanate, then mix material A and material B, then inject the mixture into the retaining ring mold 21 through a polyurethane foaming machine, remove the mold after complete curing, take out the high-density PIR retaining ring 2, install two pieces of high-density PIR retaining ring 2 on the outer surface of the working steel pipe 1, fix them with cryogenic adhesive, and seal the interface positions of the two high-density PIR retaining rings 2 with cryogenic sealant; S3, glass fiber insulation layer 3 preparation: according to the size of the steel pipe, cut glass fiber needle felt of appropriate width and wrap it on the outer wall of the steel pipe, and weave it horizontally and vertically to form a glass fiber insulation layer 3; S4, moisture-proof layer 4 production: cut a PAP aluminum foil composite film of appropriate width, and wrap it in a ring shape on the glass fiber isolation layer 3 to form a moisture-proof layer 4. The PAP film is required to be tightly wrapped, without gaps, and overlap evenly. The overlap is sealed and fixed with aluminum foil tape to ensure airtightness; S5, preparation of PIR cold insulation layer 5: a polypropylene coating is sprayed on the inner wall of the cold insulation layer mold 51, the steel pipe completed in S4 is placed on the mold, the cold insulation layer mold 51 is combined and locked, and then the steel pipe is preheated from the inside by an infrared temperature control device to ensure that the surface temperature of the pipe body is 25-30°C, and then the mold cavity is preheated by an electric fan to ensure that the temperature inside the cavity is 25-30°C, and a polyurethane foaming machine is used to mix material A and material B and then pour them into the mold cavity. After the pouring is completed, a digital temperature control insulation blanket is used outside the mold to insulate it, so as to fully mature the combined material and ensure the PIR foaming effect. After standing for a period of time, the integrated PIR cold insulation pipe is obtained after the mold is opened; S6, production of high-density polyethylene protective layer 6: put the PIR cold-insulating pipe on the transmission line for spiral operation, and extrude a molten polyethylene sheet of a certain thickness from the extruder and wrap it around the PIR cold-insulating pipe. As the PIR cold-insulating pipe continues to rotate and move forward, the extruder continuously extrudes the molten polyethylene sheet, which is superimposed and wrapped on the surface of the polyurethane layer according to the controlled pitch. After cooling, the polyethylene outer sheath tightly wraps the PIR cold-insulating pipe, and the production of the high-density polyethylene protective layer 6 is completed; S7, production of glass fiber reinforced plastic protective layer 7: place the cold-keeping pipe produced in step S6 on a workbench, rotate it at a constant speed, then automatically wrap the glass fiber pre-impregnated cloth around the cold-keeping pipe, and evenly apply epoxy resin with photoinitiator, and cure it after all-round irradiation with ultraviolet light, thereby forming the glass fiber reinforced plastic protective layer 7‌.

[0031] This manufacturing method combines the buckle mold process with the one-step injection method to prefabricate the integrated PIR cold insulation pipe, which has better compressive strength and ultra-low thermal conductivity, can significantly reduce the medium conduction consumption, and realize factory prefabrication. The raw materials and finished product performance indicators are strictly inspected and tested to achieve quality control of the entire production process.

[0032] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An integrated cast PIR cold insulation pipe, comprising a working steel pipe (1), characterized in that: The outer layer of the working steel pipe (1) is bonded with two high-density PIR retaining rings (2); the outer surface of the high-density PIR retaining ring (2) is wrapped with a glass fiber isolation layer (3); the outer surface of the glass fiber isolation layer (3) is wrapped with a moisture-proof layer (4); the outer surface of the moisture-proof layer (4) is provided with a PIR cold insulation layer (5); the outer surface of the PIR cold insulation layer (5) is wrapped with a high-density polyethylene protective layer (6); the outer surface of the high-density polyethylene protective layer (6) is provided with a glass fiber reinforced plastic protective layer (7); The two high-density PIR retaining rings (2) are bonded to the working steel pipe (1) using a cryogenic adhesive, and the interface positions of the two high-density PIR retaining rings (2) are sealed using a cryogenic sealant; The glass fiber isolation layer (3) is woven in a transverse and longitudinal interlaced manner.

2. The integrated cast PIR cold insulation pipe according to claim 1, characterized in that: The high-density PIR retaining ring (2) is a prefabricated part.

3. The integrated cast PIR cold insulation pipe according to claim 2, characterized in that: The moisture-proof layer (4) is made of a PAP aluminum foil composite film and is annularly wound around the outer surface of the glass fiber isolation layer (3).

4. The integrated cast PIR cold insulation pipe according to claim 3, characterized in that: The two ends of the PIR cold insulation layer (5) are arranged in a stepped manner.

5. The integrated cast PIR cold insulation pipe according to claim 4, characterized in that: The glass fiber reinforced plastic protective layer (7) is composed of an inner layer of glass fiber pre-impregnated cloth and an outer layer of epoxy resin.

6. The integrated cast PIR cold insulation pipe according to claim 5, characterized in that: A photoinitiator is added inside the epoxy resin.

7. A method for manufacturing an integrated cast PIR cold insulation pipe, applied to the integrated cast PIR cold insulation pipe as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Pipe selection: Pre-treat the outer surface of the working steel pipe (1) to remove oil, dirt, and dust, and inspect the appearance; S2. Prefabrication and installation of high-density PIR retaining ring (2): Take material A, which is polyether, polyester polyol and an auxiliary agent, wherein the auxiliary agent is one or more of a foaming agent, a foam stabilizer, a catalyst and a flame retardant, take material B, which is isocyanate, and then mix material A with material B. Then, inject the mixture into a retaining ring mold (21) through a polyurethane foaming machine, remove the mold after it is fully matured, take out the high-density PIR retaining ring (2), install two pieces of high-density PIR retaining ring (2) on the outer surface of the working steel pipe (1), fix them with a cryogenic adhesive, and seal the interface of the two pieces of high-density PIR retaining ring (2) with a cryogenic sealant; S3, glass fiber insulation layer (3) preparation: according to the size of the steel pipe, cut glass fiber needle felt of appropriate width and wrap it on the outer wall of the steel pipe, and weave it horizontally and vertically to form a glass fiber insulation layer (3); S4, making a moisture-proof layer (4): cutting a PAP aluminum foil composite film of suitable width, and wrapping it in a ring shape on the glass fiber isolation layer (3) to form a moisture-proof layer (4). The PAP film should be wrapped tightly, without any gaps, and with even overlaps. The overlaps should be sealed and fixed with aluminum foil tape to ensure airtightness; S5, preparation of PIR cold insulation layer (5): a polypropylene coating is sprayed on the inner wall of the cold insulation layer mold (51), the steel pipe completed in S4 is placed on the mold, and the cold insulation layer mold (51) is locked and combined, and then the steel pipe is preheated from the inside by an infrared temperature control device to ensure that the surface temperature of the pipe body is 25-30°C, and then the mold cavity is preheated by an electric fan to ensure that the temperature inside the cavity is 25-30°C, and a polyurethane foaming machine is used to mix material A and material B and then pour them into the mold cavity. After the pouring is completed, a digital temperature control insulation blanket is used outside the mold to insulate it, so as to promote the full maturation of the combined material and ensure the PIR foaming effect. After standing for a period of time, the mold is opened to obtain an integrated PIR cold insulation pipe; S6, preparation of high-density polyethylene protective layer (6): placing the PIR cold-insulating pipe on a transmission line and spirally running it, an extruder extrudes a molten polyethylene sheet of a certain thickness and winds it on the PIR cold-insulating pipe. As the PIR cold-insulating pipe continues to rotate and move forward, the extruder continuously extrude the molten polyethylene sheet, which is superimposed and wound on the surface of the polyurethane layer at a controlled pitch. After cooling, the polyethylene outer sheath tightly wraps the PIR cold-insulating pipe, completing the preparation of the high-density polyethylene protective layer (6); S7, preparation of glass fiber reinforced plastic protective layer (7): Place the cold-keeping pipe prepared in step S6 on a workbench and rotate it at a constant speed. Then, automatically wrap the glass fiber pre-impregnated cloth around the cold-keeping pipe and evenly apply epoxy resin with photoinitiator. After being cured by irradiating it in all directions with an ultraviolet spotlight, a glass fiber reinforced plastic protective layer (7) is formed.

Images