GF83.30-W-3103A | Expansion valve, location/task/design/function | 18.3.96 |
MODEL 950, 952, 953, 954 with BODY 942.899
W83.30-0006-12
Body
1 Diaphragm
2 Pin
3 Ball
A from evaporator
B to evaporator
C from condenser
D to refrigerant compressor
Function
Once the refrigerant compressor starts working, the pressure in the evaporator drops and the valve can open. The control pressures: pressure of the temperature sensor and the suction pressure downstream of the evaporator act on opposite sides on the diaphragm (1) in the head of the expansion valve. The control movements of this diaphragm are transmitted via a pin (2) on the ball (3), which closes the valve opening, and thus control the injection quantity.
If the pressure in the evaporator is reduced when the refrigerant is suctioned off, the valve opens.
The same is true when the temperature at the evaporator outlet increases. In this case, the expansion valve also permits more refrigerant into the evaporator.
Overheating of the refrigerant is approx. 2 - 4 °C in the process. Thereby it is ensured that the entire refrigerant evaporates and only gaseous refrigerant is suctioned off through the refrigerant compressor.
Refrigerant overheating is defined as the temperature difference between the vaporization temperature and the effective temperature at the evaporator outlet.
Location | The expansion valve is mounted in front of the evaporator inlet. The temperature sensor and the pressure compensation line are connected to the evaporator outlet. | ||
Task | The expansion valve has the important task to inject the amount of refrigerant into the evaporator that is needed for the best possible evaporation. It has to be controlled irrespective of the outside temperature and refrigerant compressor power and is done dependent on the evaporator pressure and the temperature at the evaporator outlet. Furthermore, the expansion valve represents a point of separation between the high and low pressure section in the refrigerant circuit. | ||
| Condenser, design/task/function/location | ||
| Evaporator block with evaporator sensor, task/function/location | ||
| Refrigerant compressor, task/function/location |