Patent ID: 8777246

Claim:
A compressed air supply assembly for operating a pneumatic assembly, the compressed air supply assembly comprising: a compressed air supply; a compressed air connection to the pneumatic assembly; a purge connection to the environment; a pneumatic main line between the compressed air supply and the compressed air connection, the pneumatic main line including an air dryer; a purge line between the compressed air connection and the purge connection; a solenoid valve arrangement including a 2/2 way control valve to control a purge valve, the 2/2 way control valve being connected to a control valve connection in a pneumatic control line connected to a pressure control connection of the purge valve, and the purge valve being connected to a purge valve connection in the purge line; and a pressure-maintaining pneumatic device connected to the pneumatic control line, the pressure-maintaining pneumatic device being adapted to maintain control pressure at the pressure control connection independently of pressure in at least one of the purge line and the pneumatic main line when the purge valve connection of the purge valve in the purge line is open.