High Pressure PU Foam Machine Parts Injection Mixing Head Corrosion Proof

Mixing head Introduction: 

The mixing head of a polyurethane high-pressure foaming machine is a precision component. Its core function is to instantly, intensely, and evenly mix components such as isocyanate (ISO, commonly known as black material) and polyol (POLY, commonly known as white material) under extremely high pressure. This mixing head then injects the components into the mold, triggering a chemical reaction that produces polyurethane foam.

The design of the mixing head directly determines the quality of the final product, including the uniformity of the foam's density, cell structure, and the presence of defects.

Mixing head Working Principle:

High-Pressure Collision Mixing

This technology is completely different from the mechanical stirring mixing principle used in low-pressure foaming machines. Its core is self-cleaning, high-pressure collision mixing.

1. High-Pressure Pumping: The main pump pressurizes the ISO and POLY components to very high levels (typically between 100-200 bar).
2. Circulation: During the non-injection phase, the component materials flow through the internal channels of the mixing head and, blocked by a piston or needle valve, return to the raw material drum via a circulation line to maintain stable material temperature and properties.
3. Injection/Mixing Phase:
· When injection is required, the actuator (pneumatic or hydraulic cylinder) activates, rapidly lifting the piston or opening the needle valve, clearing the path to the mixing chamber.
· The high-pressure component liquids are ejected at extremely high speeds (over 100 m/s) through a tiny nozzle into a narrow mixing chamber. These high-speed jets collide and shear against each other within the mixing chamber. Their immense kinetic energy breaks the liquid into extremely fine droplets, achieving instant, uniform mixing without the need for mechanical agitation.

4. Self-cleaning: After injection, the piston or needle valve quickly returns to its original position, acting like a "knife" to cut off the material flow and scrape any remaining material off the mixing chamber walls. This process effectively prevents cross-contamination and solidification blockage within the mixing head.