GB721939A - Improvements in or relating to safety valve for releasing both positive and negativeexcessive pressures - Google Patents

Abstract

721,939. Fluid-actuated valves. UNITED DAIRIES (WHOLESALE), Ltd., MATTHEWS, P., and SHEPPHEARD, G. E. Dec. 4, 1953 [Dec. 4, 1952], No. 30837/52. Class 135. A safety valve for releasing positive and negative excessive pressures from a vessel such as a transportable tank comprises a seating 10 formed on a wall of the tank or vessel or on a neck or other part 11 fixed thereto, the face of which seating is directed away from the interior of the tank or vessel and encircles an opening, a disc or plate 14 of flexible material arranged over the seating 10 and having a central port 15 and an uninterrupted periphery, a closure member 22, for the port disposed on the opposite side of the disc or plate to the seating and secured to the wall of the tank or to the neck 11. The closure member 22 is formed as a boss inside a cap 16 detachably secured to the neck 11. The seating 10 is formed at the base of a recess 13 in the end of the neck 11 which is threaded at 12 for connection to the tank. The recess 13 prevents lateral movements of the disc 14. The cap 16 is pivoted by a bolt 19 to two arms 18 projecting from the neck 11. A stainless steel washer 24 engages a shoulder 23 on the neck 11 and the cap 16 is held in the closed position by a magnet 21 mounted between the washer 24 and a projection 27 and held in place by a plate 28 secured to the projection 27. The magnet co-operates with a soft iron armature 29 welded to clips secured to the cap 16. The space 25 below the cap 14 is open to the atmosphere to allow excess fluid to pass out when the disc 14 leaves the seating 10 or to allow air to pass into the tank when the disc 14 is forced inwardly away from the boss 22. The cap 16 may be screwed on to the neck 11 in which case holes are provided through the cap into the space 25 and the cap is tethered by a chain having a swivel anchorage.