| 摘要 |
<p>A device relieves a positive pressure difference between the inside of a vessel and the outside of the vessel through an opening in the vessel. The device has a bas e portion a cap portion and a biasing means. The base portion has a means for moun ting the device in the opening; a cap seat providing an orifice through which the pre ssure difference may be relieved; and a generally hollow body portion attached to the cap seat and extending concentrically with the cap seat into the vessel. The cap portion has a cap having an external surface with a diameter larger than the diameter of the cap s eat to retain the cap external to the cap seat in sealing relationship; a rod mounted concentrically and normal to the internal surface at one end the other end exten ding into the body portion and terminating in a piston with a shoulder the piston being in concentric sliding engagement within the body portion. The biasing means has a compression spring acting between the interior of the body portion and the piston shoulder to urge the cap, into sealing relationship with the cap seat; and a damping means with the piston effectively dividing the body portion into first and second chambers a channel communicating one chamber to the other and a fluid in the chambers so movement o f the piston in either direction requires a portion of the fluid to pass through the c hannel from one chamber to the other.</p> |
