| 摘要 |
The invention relates to a pressure relief valve with a valve piston (4) displaceable within a longitudinal bore (33, 34) in a valve housing (2, 3), a valve spring (5), a plurality of O-ring seals (17, 19, 19') and a plurality of outlets (20', 20'') with outlet openings (24, 25). The object on which the invention is based is to combine the advantages of a conventional small pressure relief valve with the advantages of a large rock burst valve in a single common valve. This object is achieved essentially by the fact that the valve piston (4) has at a spacing (A) two pairs (14, 15) of rows of holes, of which at least one row (14') of one pair (14) of rows of holes reaches its open position slightly before the corresponding row (15') of the other pair (15) of rows of holes, that the ratio of the sum of the cross-sectional areas of the radial openings (21) of the pairs (14, 15) of rows of holes to the inner cross-sectional area of the valve piston (4) is from 1.4:1 to 1.5:1, and that all the O-rings (17', 19'', 19''', 22') have a Shore hardness of at least 90 Shore-A. <IMAGE>
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