Air Starting Valve-MAN B&W Engine

Air start valve installed in the cylinder head. It is opened by the control air from the starting air distributor.

Main starting air at 30bar enter in the valve through circumferential port of valve body. The air pressure will not open the valve because a spring hold the valve shut, at the area of the balance piston is the same as that of the valve lid so the valve is pneumatically balanced. 

 Fir: Air starting valve

When the valve is required to open, air at 30bar from the air start distributor enters the top of the body of the valve and acts on a piston. This force overcomes the spring force holding the valve shut and the valve opens. When the air signal from the air start distributor is vented the spring closes the valve.

When the start sequence is finished the main air start pressure is vented through holes in the main start air manifold.