Abstract: A pilot-operated diaphragm valve in which the diaphragm seats on a valve seat having an unconstricted flow annulus therearound, and support regions are provided on the valve seat and on the valve body for support of the diaphragm when in closed position. The support region on the valve seat further performs important sealing functions, as does a sealing lip disposed radially-inwardly of the sealing and support region of the valve seat. To stabilize the diaphragm at various partially and fully open positions, and to augment sealing action when the valve is closed, a spring-pressed poppet is disposed above the diaphragm and is guided by a valve stem and bearing. A peripheral region of the poppet bears a certain relationship to the sealing portions of the valve seat.

Abstract: A combined air release and vacuum breaker valve for pipelines has a ball float that acts directly upon both the vacuum breaker and air release valves which are concentric with one another and axially aligned with the ball float. To avoid adverse effects of high velocity flow of water into the float chamber, which tends to initially counteract buoyancy of the ball, a flow disturbing screen is connected to the lower end of the ball. The direct acting ball is connected to the pressure release valve member by means of a resilient lost motion connection, so that slight bouncing of the ball caused by turbulent flow in adjacent areas of the pipeline will not cause the air release valve member to bounce on and off its seat.