Working Principle of Polyurethane High Pressure Foaming Injection Machine

1. Raw Material Processing and Delivery System
When the polyurethane high pressure foaming injection machine is working, material A (polyether polyol) and material B (isocyanate) are stored in sealed material tanks respectively, and the temperature is maintained in the range of 21-25℃ through the heating system (such as electric heating or heat transfer oil circulation) to ensure the fluidity and reactivity of the raw materials. Dry compressed air is injected into the material tank due to air pressure (0.25-0.3MPa for material tank A and 0.15-0.2MPa for material tank B), and the raw materials are pushed into the delivery pipeline through the air pressure difference. The polyurethane high pressure foaming injection machine uses an axial piston pump or a low-speed gear pump to control the A/B material ratio.

2. High-pressure mixing
The low-pressure raw material (about 0.5MPa) is converted to high pressure (8-15MPa) and sprayed into the mixing chamber at high speed through the nozzle. In the mixing chamber, the A/B materials collide with each other at an ultra-high pressure of 8-13MPa and a flow rate of 10-15m/s, forming a turbulent mixture to ensure the uniformity of the chemical reaction.

III. Foaming and molding
The foaming agent (such as HCFC-141b) in the raw material releases gas (CO₂ or physical foaming agent gasification) under the action of a catalyst (such as amine compounds) to form a closed-cell foam structure. After the mixed material is injected into the mold, the foaming rate is adjusted by mold temperature control (30-60℃) to ensure uniform foam density. Through mold exhaust design or dynamic pressure adjustment, the expansion stress is balanced to prevent product deformation.