| 摘要 |
A pressure relief valve has a hollow valve body with one or more vent ports in the side wall and a small pilot opening in a first end. A lightweight sleeve, closed at one end, telescopes over the first end of the valve body to close the vent ports. A pressure actuatable element is positioned on the outer surface of the valve body end so as to block the pilot opening therein until the pressure in the valve body exceeds a predetermined value. When the pressure actuatable element unblocks the pilot opening, the interior of the closed end of the sleeve is exposed to the pressure in the valve body, causing the lightweight sleeve to move relative to the valve body to open the vent ports. Suitable pressure actuated elements include a rolling ball or a spring biased closure plate.
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