Expansion Block/Orifice Tube: Description and Operation

Refrigerant System (R-134a), Components

Restrictor







The restrictor restricts and controls refrigerant flow to the evaporator thus lowering refrigerant temperature and pressure.

Upstream of the restrictor, the refrigerant is hot and under high pressure. Downstream of the restrictor, the refrigerant is cold and under low pressure.

A strainer located upstream of the restrictor filters out any dirt or particles. Another strainer located downstream of the restrictor atomizes the refrigerant before it enters the evaporator.


NOTE:
- Insert restrictor so that Arrow -A- points to evaporator.
- Illustration shows the evaporator from an Audi 90 model.