District Heating Pipe HDPE Outer Casing Extrusion Line, Vacuum Calibration Pre-Insulated Pipe Equipment

District Heating Pipe HDPE Outer Casing Extrusion Line, Vacuum Calibration

Pre-Insulated Pipe Equipment

The equipment consists of a steel pipe chain conveyor and pipe assembling table. The conveyor continuously passes the steel pipe into the PE jacket on the assembling table.

Qingdao Huashida District Heating Pipe HDPE Outer Casing Extrusion Line is a professional HDPE outer casing extrusion system designed for DN110-560mm / DN600-1200mm / DN980-1680mm / DN1155-2000mm (outer casing diameter) pre-insulated district heating pipes.

This line features vacuum calibration for perfect roundness, patent-pending centering device to prevent eccentricity (huashida proprietary), high-speed hdpe extrusion, high-efficiency screw technology (30% output increase), proven in multiple heating pipe projects, delivering reliable HDPE casing quality for district heating networks, combined heat and power (chp) distribution, urban central heating pipelines, pre-insulated pipe manufacturing.

With vacuum calibration technology and patent-pending centering device, this system is optimized for the China, Russia, Northern Europe, Central Asia, district heating companies, pre-insulated pipe manufacturers market. Backed by over 20 years of manufacturing experience since 2003, with 58 invention patents, and proven in multiple district heating pipe projects across China and Russia, Huashida ensures stable operation, perfect roundness, and casing quality that meets GB/T 29047 and EN 253 standards.

Technical Prameters:

HDPE Jacket Process Flow:

1. Vacuum Feeding of PE Granules: The raw PE granules are automatically fed into the system via vacuum suction.
2. Hot Air Drying: The granules are dried using hot air to remove moisture, ensuring optimal extrusion quality.
3. Extrusion Plasticizing: The dried granules are plasticized through the extruder, heated and mixed to form a molten plastic mass.
4. Mold Shaping: The molten plastic is shaped into the desired pipe profile by passing through the extrusion die.
5. Vacuum Sizing: The pipe is then subjected to vacuum sizing, adjusting its dimensions to precise specifications.
6. Water Cooling: The pipe is cooled rapidly by immersion in a water tank to solidify its shape and structure.
7. Pulling Out: The solidified pipe is pulled out of the cooling tank at a controlled speed.
8. Cutting: The pipe is cut to the desired length using a precision cutting machine.
9. Carrier Laying-off: The cut pipes are then neatly laid off onto a carrier for further handling or packaging

Composition of Equipments:

1. Hopper Dryer
2. Single Screw Extruder
3. Extrusion Mould Die
4. Head Bracket
5. Vacuum Calibration Device
6. Water Cooling Tank
7. Haul-off Unit
8. Planetary Cutting Machine
9. Pipe Bracket
10. Loader
11. PLC (Programmable Logic Controller)

The production steps of the insulation layer for a pre-insulated pipe, specifically focusing on the polyurethane (PU) foam insulation, are outlined below in detail:

1. Formation of the Casing Structure:
   • The steel pipe is first inserted into the high-density polyethylene (HDPE) outer protection pipe, creating a casing structure.
   • Supports are evenly arranged in the annular space between the steel pipe and the HDPE outer pipe to maintain a uniform distance and prevent the two pipes from touching directly.
   • The two ends of the casing are sealed with flanges to ensure that the polyurethane foaming material will be contained within the space during the injection process.
2. Preparation of the Steel Pipe Surface:
   • Prior to the injection of the insulation material, the surface of the steel pipe undergoes pre-treatment such as shot blasting or blast cleaning. This step removes any impurities, rust, or scale, providing a clean and suitable surface for optimal adhesion of the polyurethane insulation.
   • Additionally, corona treatment of the polyethylene pipe shell's surface may also be performed to enhance its adhesion properties.
3. Injection of Polyurethane Foaming Material:
   • The casing structure is hoisted onto a foaming platform specifically designed for this purpose.
   • A high-pressure foaming machine is used to inject the polyurethane foaming material into the casing. The material expands and fills the entire annular space between the steel pipe and the HDPE outer pipe.