Forming process of high-temperature-resistant waste liquid steel-clad steel thermal insulation pipe

Abstract

The invention belongs to the technical field of thermal insulation pipe production, and particularly relates to a forming process of a high-temperature-resistant waste liquid steel-clad steel thermal insulation pipe, which comprises the following steps of: selecting a working pipe, an outer sheath and a thermal insulation material according to a preset material; the pipe walls of the working pipe and the outer sheath are subjected to sand blasting treatment; the outer wall of the working pipe is sequentially wrapped with heat preservation materials, the heat preservation materials are wrapped with aluminum foil reflection cloth, and the heat preservation materials and the aluminum foil reflection cloth jointly form a heat preservation layer of the working pipe. The working pipe with the heat preservation layer is sleeved with the outer sheath, and a fixing support is welded between the two ends of the working pipe and the outer sheath; the heat preservation cavity is filled with foaming polyurethane; according to the forming process, multi-point supporting can be formed on the heat preservation layer on the working pipe, the heat preservation layer is prevented from falling to the bottom of the outer sheath, it is ensured that water vapor is smoothly discharged, and the heat preservation layer is prevented from being affected with damp and losing efficacy.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation pipe production technology, specifically relating to a molding process for a high-temperature resistant waste liquid steel-clad steel thermal insulation pipe. Background Technology

[0002] Steel-clad steel insulated pipes are widely used in high-temperature steam transportation and high-temperature waste liquid treatment due to their high structural strength and excellent insulation performance. A typical steel-clad steel insulated pipe usually consists of a working pipe, an outer sheath, an insulation layer wrapped around the working pipe, and an air layer between the insulation layer and the outer sheath. The insulation layer is bound to the working pipe with binding tape. When the working pipes are welded in series on-site, pads and supports are installed at the ends of the working pipes to guide the outer sheath and overcome the problem of slight displacement caused by asynchronous expansion and contraction between the working pipe and the outer sheath. Insulation material is then wrapped around the working pipes. Finally, a connecting sleeve is added at any shortfall in the outer sheath and secured to the outer sheath with clamps. During the factory manufacturing process, metal fixing brackets are welded between the working pipe and the outer sheath to maintain their relative positions. At the pipeline laying site, it is usually necessary to first use fixed supports to ensure the coaxiality of the inner pipe to facilitate series welding. After welding is completed, the fixed supports are removed. As the insulation layer is used for a long time, moisture may seep into the joint sleeve, causing the binding tape to lose its adhesiveness, age, break and fall off. The insulation layer wrapped around the working pipe becomes loose, resulting in insulation failure. In addition, the aluminum foil reflective cloth may hang down at the bottom of the outer sleeve, affecting the diffusion and discharge of water vapor in the air layer. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention provides a molding process for a high-temperature resistant waste liquid steel-clad steel insulation pipe, which can form multi-point support for the insulation layer to prevent the insulation layer from sagging to the bottom of the outer sheath, facilitate the smooth discharge of moisture in the air layer, and prevent the insulation layer from becoming damp and failing.

[0004] The specific technical solution adopted in this invention is as follows:

[0005] A molding process for a high-temperature resistant waste liquid steel-clad steel insulation pipe, the key of which includes the following steps:

[0006] S1. Cut the working pipe, outer sheath and insulation material according to the predetermined dimensions;

[0007] S2. Sandblast the walls of the working pipe and the outer sheath respectively;

[0008] S3. Wrap insulation material around the outer wall of the working pipe in sequence, and wrap aluminum foil reflective cloth around the insulation material. The insulation material and aluminum foil reflective cloth together form the insulation layer of the working pipe.

[0009] S4. The working pipe with the insulation layer is put into the outer sheath. The gap between the working pipe and the outer sheath forms an insulation cavity. Weld a fixed bracket between the two ends of the working pipe and the outer sheath.

[0010] S5. Fill the insulation cavity with polyurethane foam;

[0011] S6. Seal both ends of the insulation cavity by wrapping them with plastic film.

[0012] In step S2, the sandblasting process uses quartz sand or corundum as abrasive, and the sandblasting pressure is 0.5-0.8 MPa.

[0013] The insulation materials include aerogel fiber blanket, ceramic fiber filament blanket and glass wool, which are wrapped around the working tube from the inside out. Aluminum foil reflective cloth is provided on the inner and outer sides of the ceramic fiber filament blanket.

[0014] In step S4, before the working tube is fitted with the outer sheath, a diaphragm is laid on the inner wall of the outer sheath, and the working tube is fitted inside the diaphragm.

[0015] In step S5, polyurethane foam is filled into the insulation cavity using a filling assembly. The filling assembly includes a support ring and a set of spray tubes spaced apart on the support ring. The inner diameter of the support ring is greater than or equal to the outer diameter of the outer sheath. The spray tubes are bent backward from the support ring and suspended. A nozzle is provided at the end of the spray tube.

[0016] The spraying pipes are arranged in an array around the support ring, the working pipe and the outer sheath are supported by the support frame, and the support ring is fixed to the ground by the fixing rod.

[0017] The support frame includes a support and an arc-shaped plate disposed on the support. The arc-shaped plate abuts against the tube wall of the outer sheath. The support is guided by a slide rail. The slide rail is fixed to the ground along the axial direction of the support ring.

[0018] In step S4, the outer sheath moves toward the support ring via the slide rail and the spray pipe enters the outer sheath, and then the working pipe is pushed into the outer sheath; in step S5, when filling with polyurethane foam, the spray pipe sprays polyurethane foam through the nozzle, and the support carries the working pipe and the outer sheath along the slide rail to make the spray pipe exit the insulation cavity. The spray pipe sprays polyurethane foam intermittently, and the polyurethane foam is segmented between the insulation layer and the outer sheath.

[0019] The beneficial effects of this invention are:

[0020] This invention employs a diaphragm layer laid on the inner wall of the outer sheath. The space between the diaphragm and the insulation layer on the working tube is filled with polyurethane foam. The polyurethane foam provides multi-point support for the insulation layer, preventing the insulation layer, especially the aluminum foil reflective cloth, from falling off due to the failure of the binding tape. The diaphragm allows the plug formed by the polyurethane foam to move relative to the inner wall of the outer sheath. That is, the diaphragm prevents the plug from sticking to the inner wall of the outer sheath, and the polyurethane foam can slide with the insulation layer inside the outer sheath.

[0021] As the spray pipe retracts from the outer sheath, it intermittently sprays polyurethane foam. Each spray pipe nozzle sprays multiple segments of polyurethane foam between the insulation layer and the diaphragm on the inner wall of the outer sheath. These multiple segments of polyurethane foam are spaced apart along the axial direction of the outer sheath. The spaced polyurethane foam forms a continuous air layer between the diaphragm and the insulation layer on the working pipe. Moisture in the air layer can be smoothly discharged through the dehumidification pipe on the outer sheath, preventing moisture from accumulating in the insulation cavity and causing the insulation material to become damp and fail or the inner wall of the outer sheath to corrode. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the insulation pipe;

[0024] Figure 3 for Figure 2 A magnified view of part A;

[0025] Figure 4 A diagram illustrating the working state of the populated component;

[0026] Figure 5 for Figure 4 Cross-sectional view;

[0027] Figure 6 This is a structural diagram of the filling component;

[0028] Figure 7 This is an axial view of the insulation pipe;

[0029] In the attached diagram, 1 is the working pipe, 2 is the outer sheath, 3 is the insulation layer, 301 is the aluminum foil reflective cloth, 302 is the aerogel fiber blanket, 303 is the ceramic fiber filament blanket, 304 is the glass wool, 4 is the fixing bracket, 5 is the foamed polyurethane, 6 is the diaphragm, 7 is the filling component, 701 is the support ring, 702 is the spray pipe, 703 is the spray nozzle, 704 is the fixing rod, 8 is the support frame, 801 is the support, 802 is the arc plate, 9 is the slide rail, and 10 is the dehumidification pipe. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0031] Specific implementation examples Figure 1 As shown, this invention relates to a molding process for a high-temperature resistant waste liquid steel-clad steel insulation pipe, comprising the following steps:

[0032] S1. Cut the working tube 1, outer sheath 2 and insulation material according to the preset dimensions.

[0033] S2. The walls of the working pipe 1 and the outer sheath 2 are sandblasted to remove rust and dirt. Quartz sand or diamond sand is used as abrasive for sandblasting, and the sandblasting pressure is 0.5-0.8MPa.

[0034] S3. Wrap insulation material around the working pipe 1 and secure each layer of insulation material with tape. The insulation material includes aerogel fiber blanket 302, ceramic fiber filament blanket 303 and glass wool 304. The aerogel fiber blanket 302, ceramic fiber filament blanket 303 and glass wool 304 are wrapped around the outer wall of the working pipe 1 in sequence. Aluminum foil reflective cloth 301 is provided between the aerogel fiber blanket 302 and the ceramic fiber filament blanket 303, between the ceramic fiber filament blanket 303 and the glass wool 304, and on the outside of the glass wool 304. The insulation material and the aluminum foil reflective cloth 301 together form the insulation layer 3 of the working pipe 1.

[0035] S4, such as Figure 2 , Figure 3 As shown, a diaphragm 6 is laid on the inner wall of the outer sheath 2. The diaphragm 6 has a tubular structure. The diaphragm 6 is installed inside the outer sheath 2. Both ends of the diaphragm 6 extend out from the ends of the outer sheath 2 and are folded outward. The ends of the diaphragm 6 are tied to the outer sheath 2. The length of the diaphragm 6 inside the outer sheath 2 is greater than the actual length of the outer sheath 2. The diaphragm 6 is located in the outer sheath 2 in a relaxed state.

[0036] The working tube 1 with the insulation layer 3 is fitted into the outer sheath 2 with the diaphragm 6, and the gap between the working tube 1 and the outer sheath 2 forms an insulation cavity.

[0037] Fixing brackets 4 are welded between the two ends of the working tube 1 and the outer sheath 2 to keep the working tube 1 and the outer sheath 2 fixed; before welding, notches are made on the diaphragm 6 for welding the fixing brackets 4. The fixing brackets 4 are arranged in a circular array around the working tube 1.

[0038] S5. Fill the insulation cavity with polyurethane foam 5 and untie the binding on the end of the diaphragm 6.

[0039] S6. Seal both ends of the insulation cavity by wrapping them with plastic film, with the plastic film overlapping the outer sheath 2 and the working tube 1.

[0040] In step S5, the expanded polyurethane 5 is filled into the insulation cavity using the filling component 7, such as... Figure 4-6 As shown, the filling component 7 includes a support ring 701 and a set of spray tubes 702 spaced apart on the support ring 701. The spray tubes 702 are connected to an external polyurethane foam supply device. The inner diameter of the support ring 701 is greater than or equal to the outer diameter of the outer sheath 2. The spray tubes 702 are bent backward from the support ring 701 and suspended. The end of the spray tube 702 is provided with a nozzle 703. The spray tubes 702 are arranged in an array around the support ring 701. The fixing rod 704 is fixed to the mounting frame or the roof, that is, the fixing rod 704 is fixed relative to the ground. The support ring 701 is fixed relative to the ground by means of the fixing rod 704.

[0041] After welding, the working pipe 1 and the outer sheath 2 are supported by a support frame 8. The support frame 8 includes a support 801 and an arc plate 802 set on the support 801. The arc plate 802 abuts against the pipe wall of the outer sheath 2. The support 801 is guided to slide with a slide rail 9. The slide rail 9 is fixed on the ground along the axial direction of the support ring 701.

[0042] In step S4, the outer sheath 2 with diaphragm 6 is placed on the arc plate 802. At this time, the position of the outer sheath 2 is adjacent to the overhanging end of the spray pipe 702. The support 801 moves along the slide rail 9 toward the support ring 701. The spray pipe 702 on the support ring 701 enters the outer sheath 2. Preferably, the end of the support ring 701 is a trumpet-shaped structure to facilitate the entry of the outer sheath 2 into the support ring 701. Then, the working pipe 1 is pushed into the outer sheath 2 from the bent side of the spray pipe 702. That is, the working pipe 1 and the outer sheath 2 move towards each other from both sides of the filling component 7. During the pushing process, the working pipe 1 supports the spray pipe 702, which may fall, between the insulation layer 3 and the outer sheath 2.

[0043] In step S5, when filling with polyurethane foam 5, the spray pipe 702 sprays the polyurethane foam 5 using the nozzle 703. The support 801 carries the working pipe 1 and the outer sheath 2 along the slide rail 9 to make the spray pipe 702 exit the insulation cavity. The spray pipe 702 sprays polyurethane foam 5 intermittently. The nozzle 703 of each spray pipe 702 sprays multiple segments of polyurethane foam 5 between the insulation layer 3 and the diaphragm 6 on the inner wall of the outer sheath 2. The multiple segments of polyurethane foam 5 are arranged at intervals along the axial direction of the outer sheath 2. Each spray pipe 702 is arranged in a circumferential array around the support ring 701. The foamed polyurethane 5 sprayed from each spray pipe 702 is arranged in a circumferential array around the working pipe 1. After the foamed polyurethane 5 solidifies, it supports the working pipe 1 and presses the diaphragm 6 tightly against the inner wall of the outer sheath 2. The diaphragm 6 is a sacrificial layer for the relative movement between the foamed polyurethane 5 and the outer sheath 2. The foamed polyurethane 5 can slide relative to the outer sheath 2 along with the insulation layer 3. The diaphragm 6 is only laid on the inner wall of the outer sheath 2, serving as a barrier to prevent the foamed polyurethane 5 from sticking to the outer sheath 2. It does not affect the relative displacement of the foamed polyurethane 5 and the outer sheath 2 when they expand and contract at different times during subsequent use.

[0044] The diaphragm 6 has a tubular structure and is provided with tear guide lines. After the polyurethane foam 5 is cured, the part of the diaphragm 6 that is in contact with the polyurethane foam 5 can be pulled out, or the diaphragm 6 can be divided into multiple strips and formed into a tube inside the outer sheath 2. After curing, the part that is not touched by the polyurethane foam 5 can be pulled out to avoid the diaphragm 6 being damaged and blocking the moisture outlet later.

[0045] In this embodiment, a polyurethane foam 5 is added between the insulation layer 3 on the working pipe 1 and the outer sheath 2. The polyurethane foam 5 provides multi-point support for the insulation layer 3 on the working pipe 1, preventing the insulation layer 3 from sagging to the bottom of the outer sheath 2 due to the failure of the binding tape. The diaphragm 6 allows the insulation layer 3 and the outer sheath 2 to maintain relative movement. The spaced polyurethane foam 5 forms a through-air layer between the diaphragm 6 and the working pipe 1, creating a path for air convection or diffusion. Figure 7 As shown, a desiccant pipe 10 is installed on the top of the outer sheath 2 or on the connecting sheath, and the desiccant pipe 10 is located between the polyurethane foam 5. The desiccant pipe 10 is connected to the air layer, and the moisture in the air layer can be smoothly discharged through the desiccant pipe 10 on the outer sheath 2. While retaining the air layer, it prevents moisture from accumulating in the insulation cavity, which would cause the insulation material to become damp and fail or the inner wall of the outer sheath 2 to corrode.

Claims

1. A molding process for a high-temperature resistant waste liquid steel-clad steel insulation pipe, characterized in that, Includes the following steps: S1. Cut the working tube (1), outer sheath (2) and insulation material according to the predetermined dimensions; S2. Sandblast the walls of the working pipe (1) and the outer sheath (2) respectively; S3. Insulation material is wrapped around the outer wall of the working tube (1) in sequence, and aluminum foil reflective cloth (301) is wrapped around the insulation material. The insulation material and aluminum foil reflective cloth (301) together form the insulation layer (3) of the working tube (1). S4. The working pipe (1) with the insulation layer (3) is fitted into the outer sheath (2). The gap between the working pipe (1) and the outer sheath (2) forms an insulation cavity. Fixing brackets (4) are welded between the two ends of the working pipe (1) and the outer sheath (2). S5. Fill the insulation cavity with polyurethane foam (5); S6. Seal both ends of the insulation cavity by wrapping them with plastic film.

2. The forming process of a high-temperature resistant waste liquid steel-ladle insulation pipe according to claim 1, characterized in that: In step S2, the sandblasting process uses quartz sand or corundum as abrasive, and the sandblasting pressure is 0.5-0.8 MPa.

3. The forming process of a high-temperature resistant waste liquid steel-ladle insulation pipe according to claim 1, characterized in that: The thermal insulation materials include aerogel fiber blanket (302), ceramic fiber filament blanket (303) and glass wool (304). The aerogel fiber blanket (302), ceramic fiber filament blanket (303) and glass wool (304) are wrapped around the working tube (1) from the inside to the outside. Aluminum foil reflective cloth (301) is provided on the inner and outer sides of the ceramic fiber filament blanket (303).

4. The forming process of a high-temperature resistant waste liquid steel-clad steel insulation pipe according to claim 1, characterized in that: In step S4, before the working tube (1) and the outer sheath (2) are fitted together, a diaphragm (6) is laid on the inner wall of the outer sheath (2), and the working tube (1) is fitted inside the diaphragm (6).

5. The forming process of a high-temperature resistant waste liquid steel-clad steel insulation pipe according to claim 4, characterized in that: In step S5, polyurethane foam (5) is filled into the insulation cavity by means of filling component (7). The filling component (7) includes a support ring (701) and a set of spray tubes (702) spaced apart on the support ring (701). The inner diameter of the support ring (701) is greater than or equal to the outer diameter of the outer sheath (2). The spray tubes (702) are bent backward from the support ring (701) and suspended. The end of the spray tubes (702) is provided with a nozzle (703).

6. The forming process of a high-temperature resistant waste liquid steel-clad steel insulation pipe according to claim 5, characterized in that: The spray pipe (702) is arranged in an array around the support ring (701). The working pipe (1) and the outer sheath (2) are supported by the support frame (8). The support ring (701) is fixed relative to the ground by means of the fixing rod (704).

7. The forming process of a high-temperature resistant waste liquid steel-clad steel insulation pipe according to claim 6, characterized in that: The support frame (8) includes a support (801) and an arc plate (802) set on the support (801). The arc plate (802) abuts against the tube wall of the outer sheath (2). The support (801) is guided to slide with the slide rail (9). The slide rail (9) is fixed on the ground along the axial direction of the support ring (701).

8. The forming process of a high-temperature resistant waste liquid steel-ladle insulation pipe according to claim 7, characterized in that: In step S4, the outer sheath (2) moves toward the support ring (701) by means of the slide rail (9) and the spray pipe (702) enters the outer sheath (2), and then the working pipe (1) is pushed into the outer sheath (2); in step S5, when filling the foamed polyurethane (5), the spray pipe (702) sprays the foamed polyurethane (5) by means of the nozzle (703), and the support (801) carries the working pipe (1) and the outer sheath (2) along the slide rail (9) to make the spray pipe (702) exit the insulation cavity. The spray pipe (702) sprays the foamed polyurethane (5) intermittently, and the foamed polyurethane (5) is set in sections between the insulation layer (3) and the outer sheath (2).

Images