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CN-122008581-A - Polyurethane spraying polyethylene winding heat-insulating pipe production system and process

CN122008581ACN 122008581 ACN122008581 ACN 122008581ACN-122008581-A

Abstract

The invention relates to a polyurethane spraying polyethylene winding heat-insulating pipe production system and process, wherein the production process comprises the following steps of 1) spraying a layer of polyurethane foaming material on a working steel pipe, solidifying the foaming material to obtain a heat-insulating base layer, controlling the thickness of the heat-insulating base layer to be smaller than the design thickness of a heat-insulating layer, calculating the difference between the thickness of the solidified heat-insulating base layer and the design thickness of the heat-insulating layer, taking the difference as a reference value, 2) spraying a layer of composite layer of polyurethane foaming material and polyurethane solid particles on the surface of the solidified heat-insulating base layer, winding a polyethylene outer protective layer before solidifying the composite layer, and solidifying the composite layer to obtain the polyurethane spraying polyethylene winding heat-insulating pipe, wherein the granularity of the polyurethane solid particles is determined according to the reference value calculated in the step 1). The invention can solve the difficult problem of controlling the thickness of the polyurethane heat-insulating layer and can improve the bonding strength between the polyethylene outer protective layer and the polyurethane heat-insulating layer.

Inventors

  • Yu Lukun
  • TIAN YOUJIA

Assignees

  • 河南锐特热力管道科技有限公司

Dates

Publication Date
20260512
Application Date
20260312

Claims (7)

  1. 1. The production process of the polyurethane spraying polyethylene winding heat preservation pipe is characterized by comprising the following steps of: 1) Spraying a layer of polyurethane foaming material on the working steel pipe, curing the polyurethane foaming material to obtain a heat-insulating base layer, controlling the thickness of the heat-insulating base layer to be smaller than the design thickness of the heat-insulating layer, calculating the difference between the thickness of the cured heat-insulating base layer and the design thickness of the heat-insulating layer, and taking the difference as a reference value; 2) And (3) spraying a layer of composite layer of polyurethane foaming material and polyurethane solid particles on the surface of the cured heat-insulating base layer, winding the polyethylene outer protective layer before the composite layer is cured, and curing the composite layer to obtain the polyurethane spray-coated polyethylene winding heat-insulating pipe, wherein the granularity of the polyurethane solid particles is determined according to the reference value calculated in the step (1).
  2. 2. The process for producing a polyurethane-coated polyethylene-wrapped insulation pipe according to claim 1, wherein in step 1), the reference value is not more than 1/5 of the design thickness.
  3. 3. The process for producing a polyurethane-coated polyethylene-wrapped insulation pipe according to claim 1, wherein in step 2), the polyurethane solid particles are obtained by pulverizing and sieving recycled polyurethane waste.
  4. 4. A process for producing a polyurethane-sprayed polyethylene-wrapped insulation pipe according to claim 3, wherein in step 2), the particle size of the polyurethane solid particles is 1.0 to 1.5 times the reference value.
  5. 5. The utility model provides a polyurethane spraying polyethylene winding insulating tube production system, includes polyurethane spraying district and polyethylene winding district, its characterized in that still includes polyurethane waste recovery district, and polyurethane waste recovery district is equipped with polyurethane waste crusher, screening machine, storage storehouse and conveying mechanism, and conveying mechanism is connected to polyurethane solid particle charging mechanism, and charging mechanism's discharge gate is used for adding polyurethane solid particle in the outside of working steel pipe, and the discharge gate is equipped with the polyurethane shower nozzle along the upstream side of working steel pipe direction of rotation.
  6. 6. The polyurethane-sprayed polyethylene-wrapped insulation pipe production system according to claim 5, wherein the polyurethane-sprayed area and the polyethylene-wrapped area are both spiral conveying lines, and the feeding mechanism is arranged in the polyurethane-sprayed area.
  7. 7. The polyurethane-sprayed polyethylene-wrapped insulation pipe production system according to claim 5, wherein the polyurethane-sprayed area is conveyed by a mobile trolley, the polyethylene-wrapped area is conveyed by a spiral conveying line, the feeding mechanism is arranged in the polyethylene-wrapped area, and a polyurethane spray head is arranged at the inlet end of the polyethylene-wrapped area.

Description

Polyurethane spraying polyethylene winding heat-insulating pipe production system and process Technical Field The invention belongs to the technical field of production of heat-insulating pipes, and particularly relates to a production system and a production process of a polyurethane spraying polyethylene winding heat-insulating pipe. Background The polyurethane spraying polyethylene winding heat-insulating pipe is commonly used in the fields of petrochemical industry, thermal transmission and the like, and has the structure that a polyurethane heat-insulating layer is sprayed outside a main pipeline, and a polyethylene outer protective layer is wound outside the cured polyurethane heat-insulating layer. The polyurethane heat-insulating layer plays a key role in heat insulation, and the thickness of the polyurethane heat-insulating layer is an important control index. When the thickness of the cured heat-insulating layer is smaller than the design requirement, the problem can be solved through repair spraying, but the heat-insulating layer needs to be cured again to be placed and waited, so that the efficiency is reduced. The thickness is too large, so that the material consumption is increased, and the reworking treatment difficulty is high. The polyurethane insulation layer is subjected to foaming expansion and curing shrinkage stages after being sprayed, and the thickness of the cured insulation layer is generally controlled by empirically adjusting the spraying thickness. Other methods are also used to improve the accuracy of thickness control, such as the method for calculating the thickness and density of the sprayed winding insulating tube disclosed in patent CN 202311705757.6. In addition, the bonding strength of the polyethylene outer protective layer and the polyurethane heat-insulating layer is also an important factor affecting the quality of the heat-insulating pipe. A process for producing a high performance spray wound insulating tube as disclosed in patent CN 202011421267. X, a hot melt adhesive powder for polyethylene/polyurethane foam bonding, and patent CN 201911385158.4. The bonding strength is enhanced by adding an adhesive medium between the polyethylene outer protective layer and the polyurethane heat insulation layer, but the above proposal also increases the cost of raw materials. Disclosure of Invention Aiming at the defects existing in the prior art, the invention firstly provides a production process of a polyurethane spraying polyethylene winding heat-insulation pipe, which comprises the following specific scheme: A polyurethane spraying polyethylene winding heat preservation pipe production process comprises the following steps: 1) Spraying a layer of polyurethane foaming material on the working steel pipe, curing the polyurethane foaming material to obtain a heat-insulating base layer, controlling the thickness of the heat-insulating base layer to be smaller than the design thickness of the heat-insulating layer, calculating the difference between the thickness of the cured heat-insulating base layer and the design thickness of the heat-insulating layer, and taking the difference as a reference value; 2) And (3) spraying a layer of composite layer of polyurethane foaming material and polyurethane solid particles on the surface of the cured heat-insulating base layer, winding the polyethylene outer protective layer before the composite layer is cured, and curing the composite layer to obtain the polyurethane spray-coated polyethylene winding heat-insulating pipe, wherein the granularity of the polyurethane solid particles is determined according to the reference value calculated in the step (1). In the invention, the heat-insulating base layer formed by the first polyurethane spraying is controlled in a range smaller than the design thickness, and the thickness of the heat-insulating layer is finally increased to the design thickness by the second spraying. The method is beneficial to controlling the thickness of the heat preservation layer. The composite layer of polyurethane solid particles and polyurethane foaming materials is adopted in the second spraying, the polyurethane solid particles have certain strength, and can play a supporting role, so that the foaming expansion of polyurethane is prevented from being influenced by the extrusion of the second spraying layer during polyethylene winding. Polyethylene winding can be directly carried out after secondary spraying, so that curing waiting time after spraying is omitted. In addition, the polyurethane foaming material sprayed for the second time has better adhesive capability before solidification, and can improve the connection strength between the polyethylene layer and the heat-insulating base layer formed after primary spraying solidification. Further, in step 1), the reference value is not more than 1/5 of the design thickness. Further, in the step 2), the polyurethane solid particles are obtained by crushing and sc