This system can control the pressure difference between inside capsule and outside capsule to be a certain number automatically.When the pressure difference is lower than the setting value,let the nitrogen in;when it is higher than the setting value,the air of inside capsule will be exhausted.

1. The setting values of pressure difference can be setted from the colorful touch screen,including the sensor range measurement,the open value and the close value of the nitrogen solenoid,the open value and the close value of the exhaust solenoid.
2. When the pressure difference is lower than the setting value,DDC controller will send an open signal to the nitrogen solenoid,it takes action and the nitrogen is in the capsule,the pressure of inside capsule is increasing.DDC controller again send the close signal to the nitrogen solenoid and it close when the pressure difference reaches to the highest setting value.
3. When the pressure difference is higher the the highest setting value,DDC controller will send an open signal to the other solenoid,the inside air will exhaust out unless the pressure difference is down to the admitted value.