8.5.5. Broad valve

The broad valve provides sharp reduction of pressure of liquid coolant.
At the same time coolant is sprayed that facilitates evaporation process.
The broad valve also regulates a consumption of the coolant given to the evaporator.
The consumption of coolant is regulated by the size of opening of the spherical valve in the broad valve.
The size of opening is regulated by balance of pressure R-134a upon a diaphragm and the resulting pressure force at the exit of the evaporator (PI) – on the lower part of a diaphragm and force of a spring (Fs) operating on the sharovy valve.
When PI increases, temperature of the temperature sensor about a diaphragm increases, and Pd heated R-134a – increases by a diaphragm.
When Pd is more than PI + than Fs, the diaphragm caves in down, and the shaft attached to the end of a core of the temperature sensor pushes the sharovy valve down, increasing a coolant consumption.

Fig. 8.65. Principle of operation of the broad valve: 1 – diaphragm; 2 – temperature sensor; 3 – shaft; 4 – sharovy valve; 5 – spring; 6 – from the evaporator; 7 – to the evaporator; 8 – from the condenser; 9 – on the condenser; 10 – spring force; 11 – HFC-134a pressure; 12 – pressure at the exit

When coolant temperature at the exit of the evaporator decreases, PI + Fs becomes more, than Pd, the sharovy valve rises, and the consumption of coolant decreases.