Basic Refrigerant Pressure Regulators
Orifice Tubes and Expansion Valves are the components used seperate the high and low pressure side of the refrigerant system.Think of these two pressure regulators like the nozzle on your garden hose. On one side you have a high pressure liquid, and the spray coming out the other end is a low pressure liquid. When this low pressure liquid is sprayed into the evaporator it is able to boil because it's no longer under high pressure. Boiling liquids of any type can absorb great amounts of heat. Refrigerants like R12 and R134a are used in automotive air conditioning systems because they boil at very low temperatures. It's the pressure regulator that allow the refrigerant to go from a hot high pressure liquid to a low pressure boiling liquid.
While many variations of refrigerant pressure regulators have been introduced since the 1950's. Those listed on the left are the most commonly used in today's vehicles.
