The D777 purge and pressurization system provides purge flows up to 6,000 Nl/min and is ideal for medium to large Ex p motors.

The system includes a control unit (CU) and a ventilation unit (RLV). The control unit contains pneumatic logic for monitoring and controlling air flow, pressure and purge time, 

and provides system outputs. The RLV measures the purge flow at the outlet and provides overpressure protection for the machine.

The D777 features Expo’s Leakage Compensation System (CLAPS). The system is able to detect changes in pressure inside the housing and adjust leak compensation accordingly.

Pressure changes typically occur during sudden starts of large rotating machines, but can also be caused by changes in operating temperature. The system is specifically designed to 

maintain stable internal pressure within the motor housing.

D777 equipment is equipped with a motor cavity pressure gauge, which can display the motor cavity pressure in real time.

The D777 device has two minimum pressure monitoring points, which can more accurately control the internal pressure state of the motor.

*There are a number of system variants available covering alternative alarm output connections - see specifications and downloads for further details.