8.5.5. Broad valve
The broad valve provides sharp reduction of pressure of a liquid coolant.
Thus the coolant is sprayed that facilitates evaporation process.
The broad valve also regulates an expense of a coolant submitted to the evaporator.
The expense of a coolant is regulated by size of opening of the spherical valve in the broad valve.
The size of opening is regulated by balance of pressure R-134a on a diaphragm and a resultant pressure force on an evaporator (PI) exit – on the lower part of a diaphragm and force of the spring (Fs) operating on the sharovy valve.
When PI increases, the temperature of the temperature sensor about a diaphragm raises, and Pd warm R-134a – increases by a diaphragm.
When Pd is more than PI + Fs, a diaphragm caves in down, and a shaft attached to the end of a core of the temperature sensor, pushes down the sharovy valve, increasing a coolant expense.
|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-force of a spring; 11-pressure of HFC-134a; 12-pressure on an exit
When the coolant temperature on an exit of the evaporator decreases, PI + Fs becomes more than Pd, the sharovy valve rises, and the expense of a coolant decreases.