| 摘要 |
A low pressure relief valve having a flow passage therethrough providing fluid communication between the interior and exterior of a vessel the interior of which is under a low positive or negative pressure. A valve port in the flow passage has a valve seat therearound and a closure member is carried in said valve body for engagement with the valve seat to block fluid communication between the interior and exterior of said vessel. The closure member is of a preselected weight and is free to disengage the valve seat in response to a predetermined increased pressure differential between the vessel interior and exterior, without being affected by any other force than gravity, to permit fluid communication through the flow passage for reducing the pressure differential.
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