1.At the beginning, main valve spool of Self-operated micro pressure control valve keeps closed under spring11 action force. Director 08 keeps open under spring 17 action force.

2. The medium flows into Self-operated micro pressure control valve under arrow direction, through relief valve 06, flow to director 08, through director 08 and throttle valve 13,flow to actuator 07 diaphragm chamber below. The pressure from actuator07 diaphragm chamber below is rising. The main valve will open under pressure. The medium flows into the valve,through pressure tap 09 and 21,then flow into the actuator07 diaphragm chamber above and director 08 diaphragm chamber above.

3.When the pressure P2 after valve is rising, the pressure P4 acting on the actuator 07 diaphragm chamber above is rising, main valve opening degree is reducing and pressure  after valve is reducing(initial adjustment). Meanwhile,the pressure P6 acting on  the director 08 diaphragm chamber above is rising and director 08 opening degree is reducing. The pressure P5 into actuator 07 diaphragm chamber below is reducing. The Self-operated micro pressure control valve main valve opening degree is reducing further and the pressure after valve keeps reducing(fine adjustment).

4.When the pressure P2 after valve is reducing, the pressure P4 acting on the actuator 07 diaphragm chamber above is reducing.Main valve opening degree is increasing,and pressure after valve is rising(initial adjustment). Meanwhile, the pressure P6 into director 08 diaphragm chamber above is reducing , director 08 opening degree is increasing, and pressure P5 into the  actuator 07 diaphragm chamber below is rising. The main valve of Self-operated micro pressure control valve opening degree is increasing further and the pressure after valve keeps increasing(fine adjustment).

5.The main valve spool of Self-operated micro pressure control valve and director 08 won’t stop working until it reaches the set value. At this moment, the pressure after valve is set value,  dynamic decompression can be realized.