Construction method for high-pressure clean small-caliber pipeline

Abstract

The invention discloses a construction method of a high-pressure clean small-caliber pipeline, and relates to the technical field of high-pressure clean pipelines, a thin-wall specially-made seamless steel pipe is adopted to meet the high-pressure requirement, the wall thickness of the seamless steel pipe is 1.24 mm, the pressure-resistant standard is 3700 psi-25 Mpa, the inner wall of the seamless steel pipe is treated through a bright annealing process (BA) or electrolytic polishing (EP), the corrosion resistance is improved, and the corrosion resistance of the seamless steel pipe is improved. The pipelines are connected through an automatic welding machine, welding seams are smooth and free of oxidation, the pipelines are connected through automatic welding, and elbows are directly bent on site, passivated and degreased; according to the construction method of the high-pressure clean small-caliber pipeline and the construction method of the high-pressure clean small-caliber pipeline, the cleanliness is improved, the internal roughness ra of the pipeline can be within 0.25 mu m, clamping sleeve connection is basically adopted, a bend is bent in a simmering mode, the construction time is greatly shortened, the construction efficiency is improved, and the construction cost is reduced. The construction period is shortened, the high-quality clamping sleeve joint can be dismounted and mounted for 25 times, and later maintenance is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure clean pipelines, and is mainly used for small-diameter (less than or equal to 3 / 4 inch) pipelines with high pressure (up to 25Mpa) and cleanliness requirements (ra less than 0.5um), such as auxiliary agent and catalyst feeding pipe pipeline projects for high-pressure polymerization reactions, and specifically relates to a construction method for high-pressure clean small-diameter pipelines. Background Art

[0002] With the need for high-quality development of the country, the purity and cleanliness requirements of new materials are getting higher and higher, especially for electronic-grade chemicals, ultra-clean polymers, etc. Their production equipment and pipelines must be resistant to high pressure and corrosion, and polished and clean, with a clean polishing degree of less than 0.5um; Traditional high-pressure small pipeline design and construction practices: The design selection is often thick-walled high-pressure pipelines, according to ASMEB36.19 or HG20553la steel pipe specifications, such as 1 / 2-inch high-pressure pipelines with an outer diameter of 21.5mm and a wall thickness of sch160 up to 4.78mm. Pipes and elbows are manually welded and high-pressure flanges are connected. This traditional thick-walled small pipe is welded. On the one hand, welding is difficult, and high-pressure resistance requires NDT to ensure that the pipeline is concave and convex, and the internal molding is difficult to control. Concave and convex are easy to accumulate materials and are not clean; thick-walled pipes cannot be subjected to BA bright annealing process, and have poor corrosion resistance; thick-walled pipes have a small inner diameter, and it is difficult to do machine polishing and electric polishing, which affects the cleanliness of the pipeline. For this reason, we have improved the above-mentioned existing technologies based on actual usage. Summary of the invention

[0003] The object of the present invention is to provide a construction method for a high-pressure clean small-diameter pipeline to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] 4. A construction method for a high-pressure clean small-diameter pipeline, the construction method comprising the following steps:

[0006] S1: Use thin-walled special seamless steel pipe to meet the requirements of high pressure, and its wall thickness is 1.24mm, and the pressure resistance standard is: 3700psi-25Mpa;

[0007] S2: The inner wall of the seamless steel pipe is treated by bright annealing (BA) or electrolytic polishing (EP) to improve corrosion resistance;

[0008] S3: The pipe connection adopts automatic welding machine to ensure smooth and non-oxidized welds. The pipes are connected by automatic welding. The elbows are directly bent on site and passivated to remove grease.

[0009] S4: The tee adopts sleeve-type finished forged tee, the valve adopts high-pressure ferrule valve, and is connected to the valve by ferrule. It is connected to local equipment by customized adapters and standard flanges. The local connection with the equipment adopts flanges and customized forged adapters. The tail processing progress of the customized adapter is: external dimension + / -0.08mm, inner wall polishing degree is less than or equal to 0.5um, connecting industrial standard flanges and tube pipes, and the flange, adapter head, valve, pipeline or NPT connector are connected as a whole.

[0010] Preferably, the flange, adapter head, valve, pipe or NPT joint integrated connection structure described in step S4 includes a WN flange (1), a customized adapter (2) is welded on the top of the WN flange (1), a connecting pipe is arranged on the top of the customized adapter (2), and a ferrule high-pressure valve (3) is arranged on the top of the connecting pipe, a connecting pipe is arranged on the top of the ferrule high-pressure valve (3), a connecting pipe is arranged on the top of the ferrule high-pressure valve (3), and an NPT joint (4) is arranged on the top of the connecting pipe, and a ferrule (5) is arranged on the inner wall of the NPT joint (4).

[0011] Preferably, the connection process to the valve using a ferrule connection includes: first, fully insert the ferrule into the NPT connector and press against its internal shoulder position; second, tighten the nut on the NPT connector with your fingers; second, mark the nut at the 6 o'clock position; third, firmly hold the connector body of the NPT connector and tighten the nut above one and a quarter turns to stop at the 9 o'clock position.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The construction method of the high-pressure clean small-diameter pipeline provided by the present invention improves the cleanliness. The internal roughness of the pipeline can reach within ra=0.25um. The ferrule connection is basically adopted, and the elbow is bent, which greatly reduces the construction time and shortens the construction period. The high-quality ferrule joint can be disassembled and installed 25 times, which is convenient for later maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the integrated connection structure of the present invention;

[0015] Figure 2 It is a schematic diagram of the connection joint between the valve and the ferrule of the present invention.

[0016] In the figure: 1. WN flange; 2. Customized adapter; 3. Compression fitting high-pressure valve; 4. NPT connector; 5. Compression fitting tube. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-2 The present invention provides a technical solution: a construction method for a high-pressure clean small-diameter pipeline, the construction method comprising the following steps:

[0019] S1: Use thin-walled special seamless steel pipe to meet the requirements of high pressure, and its wall thickness is 1.24mm, and the pressure resistance standard is: 3700psi-25Mpa;

[0020] S2: The inner wall of the seamless steel pipe is treated by bright annealing (BA) or electrolytic polishing (EP) to improve corrosion resistance;

[0021] S3: The pipe connection adopts automatic welding machine to ensure smooth and non-oxidized welds. The pipes are connected by automatic welding. The elbows are directly bent on site and passivated to remove grease.

[0022] S4: The tee adopts sleeve-type finished forged tee, the valve adopts high-pressure ferrule valve, and is connected to the valve by ferrule. It is connected to local equipment by customized adapters and standard flanges. The local connection with the equipment adopts flanges and customized forged adapters. The tail processing progress of the customized adapter is: external dimension + / -0.08mm, inner wall polishing degree is less than or equal to 0.5um, connecting industrial standard flanges and tube pipes, and the flange, adapter head, valve, pipeline or NPT connector are connected as a whole.

[0023] Preferably, the flange, adapter head, valve, pipe or NPT joint integrated connection structure described in step S4 includes a WN flange, a customized adapter is welded on the top of the WN flange, a connecting pipe is arranged on the top of the customized adapter, and a ferrule high-pressure valve is arranged on the top of the connecting pipe, a connecting pipe is arranged on the top of the ferrule high-pressure valve, a connecting pipe is arranged on the top of the ferrule high-pressure valve, and an NPT joint is arranged on the top of the connecting pipe, and a ferrule tube is arranged on the inner wall of the NPT joint.

[0024] The connection process with the valve using a ferrule connection includes: first, fully insert the ferrule 5 into the NPT connector 4 and press against its internal shoulder position; second, tighten the nut on the NPT connector 4 with your fingers; second, mark the nut at the 6 o'clock position; third, firmly hold the connector body of the NPT connector 4, and tighten the nut above one and a quarter turns to stop at the 9 o'clock position.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for a high-pressure clean small-diameter pipeline, characterized in that: The construction method includes the following steps: S1: Use thin-walled special seamless steel pipe to meet the requirements of high pressure, and its wall thickness is 1.24mm, and the pressure resistance standard is: 3700psi-25Mpa; S2: The inner wall of the seamless steel pipe is treated by bright annealing (BA) or electrolytic polishing (EP) to improve corrosion resistance; S3: The pipe connection adopts automatic welding machine to ensure smooth and non-oxidized welds. The pipes are connected by automatic welding. The elbows are directly bent on site and passivated to remove grease. S4: The tee adopts sleeve-type finished forged tee, the valve adopts high-pressure ferrule valve, and is connected to the valve by ferrule. It is connected to local equipment by customized adapters and standard flanges. The local connection with the equipment adopts flanges and customized forged adapters. The tail processing progress of the customized adapter is: external dimension + / -0.08mm, inner wall polishing degree is less than or equal to 0.5um, connecting industrial standard flanges and tube pipes, and the flange, adapter head, valve, pipeline or NPT connector are connected as a whole.

2. A construction method for a high-pressure clean small-diameter pipeline according to claim 1, characterized in that: The flange, adapter head, valve, pipe or NPT joint integrated connection structure described in step S4 includes a WN flange (1), a customized adapter (2) is welded on the top of the WN flange (1), a connecting pipe is arranged on the top of the customized adapter (2), and a ferrule high-pressure valve (3) is arranged on the top of the connecting pipe, a connecting pipe is arranged on the top of the ferrule high-pressure valve (3), a connecting pipe is arranged on the top of the ferrule high-pressure valve (3), and an NPT joint (4) is arranged on the top of the connecting pipe, and a ferrule (5) is arranged on the inner wall of the NPT joint (4).

3. A construction method for a high-pressure clean small-diameter pipeline according to claims 1 and 2, characterized in that: The process of connecting the ferrule to the valve includes: first, fully insert the ferrule (5) into the NPT connector (4) and press against the shoulder inside; second, tighten the nut on the NPT connector (4) with your fingers; second, mark the nut at the 6 o'clock position; third, firmly hold the connector body of the NPT connector (4) and tighten the nut on it one and a quarter turns to stop at the 9 o'clock position.

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