| 摘要 |
A valve for venting air from the pumping chamber of a liquid pumping system. A valve plate is normally held in open position remote from the valve seat by a spring. A flexible diaphragm is attached to the valve plate and divides the valve housing into a through passage and a chamber which communicates with the inlet port of the valve. The valve seat-valve plate arrangement defines a venturi region in the through passage of the valve. Under low pressure, low volume flow conditions, the valve remains in open position. As the flow rate increases, the decrease in pressure across the venturi together with the increased pressure in the chamber behind the diaphragm overcomes the spring pressure to close the valve.
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