Polyurethane Spray Foam polyethylene Wrapping Preinsulated Pipe Production Line
PU Foaming spary Preinsulation Pipe Continuous Production Line
1. Pipe structure
Our company independently developed the spray winding insulation pipe production line, which consists of three parts: shot blasting and rust removal production line, polyurethane spraying production line, and PE winding production line.
2. Polyurethane spray-wrapped insulated pipe is more efficient than the traditional "pipe-in-pipe" process.
1. Its production requires no support, preventing thermal bridges and shortened service life.
2. High-pressure spraying ensures uniform foam density and precise material application.
3. The outer sheath is wound without internal stress, allowing for reduced thickness and material savings.
This process not only improves product performance stability but also significantly reduces the production and operating costs of heating pipe networks.
3. Technological flow:
(1). Steel pipe rust removal: use a hydraulic lifter to transport the steel pipe to conveying line. The steel pipe rotates and enters the shot blasting chamber. When the internal sensor collects the signal of incoming steel pipe, the shot blasting machine starts to work. The shooting projectiles hits the outer surface of the steel pipe, removing rust and impurities attached to pipe surface, and the steel pipe moves onto the conveying line. After shot blasting treatment, the outer surface of the steel pipe meets the requirements of SA2.5.
(2). Polyurethane spraying: The steel pipe moves forward at a constant speed on rotating wheels. The spraying robot blow foaming materials to form umbrella shaped fog to evenly spray it onto surface of the rotating steel pipe. The polyurethane raw materials foam within a short period of time to achieve the required compressive strength and design thickness. When the insulation layer is very thick, multiple times of spraying can be required.
(3). Polyethylene pipe winding: The steel pipe that has been coated with polyurethane insulation layer rotates and moves along the conveying line. The extruder extrudes a certain thickness of molten polyethylene sheet and winds it on outer surface of the insulation layer. As the insulated steel pipe continues to move forward, the extruder continuously extrudes the molten polyethylene sheet material and wraps it on the surface of the polyurethane layer to form protective layer.
(4). Spray cooling: The semi-finished pipe wrapped with a polyethylene outer protective layer is cooled by an online spraying device. The polyethylene outer protective layer tightly wraps the polyurethane insulation layer on the steel pipe, completing the production of insulated steel pipe.
(5). Tracking and cutting: online track the pipe and cut automatically. When the sensor detects incoming pipe, the control system automatically starts the cutting saw. While the saw blade rotates at high speed, the cutting mechanism performs circumferential cutting around the pipe. Online cutting not only ensures high quality cutting ends, but also ensures the continuity of production and improves production efficiency. 4. Main indices of the composite pipe
Item | Standard value | Tested value |
Pipe diameter | DN500-DN1620 |
|
OD contraction rate | <=2% | 1.46 |
Radial shear strength | ≥0.12(23±2ºC)MPa ≥0.08(140±2ºC)MPa | 0.14 0.09 |
Shock strength | (-20ºC, 3Kg, hammer falls from 2 meters high) No visible cracks | OK |
Peak Operating temperature | 140ºC | 150ºC |
Continuous operating temperature | 120ºC | 140ºC |
Service life | ≥30 years | OK |

PU Foaming spary Preinsulation Pipe Continuous Production Line
5.. Main line Composition of the polyurethane coating steel preinsulated pipe equipment:
No. | name |
1 | External wall Shot blasting rust removel machine |
2 | Medium-frequency induction heating furnace |
3 | Polyurethane spray foaming unit |
4 | pipe rotator trolley |
5 | Single screw extruder and diehead mould |
6 | Finished pipe ends trimming machine |
7 | pipe Conveyers and racks |
8 | Electrical system and PLC |
Rust Removal
PE film jacket wrapping

PE Jacket Water quenching
Qingdao Huashida Machinery Co., Ltd was established in 2003. Since its inception, Huashida has focused on plastic polyurethane insulation pipe production line, 3LPE anticorrosion pipe production line, large diameter underground pipe production line and plastic pipe joints for 20 years. We always attach great importance to research and development,collaborating closely with Beijing University of chemical technology, Qingdao university of technology and scientific research institutions. by absorbing advanced technology home and abroad, after 22 years of endeavor we now rank one of the top 3 manufacturers in the industry in China. Huashida machines have been well received in Saudi Arabia, Kazakhstan, Uzbekistan, United Arab Emirates, Turkey, Russia, etc.