| 摘要 |
<p>The valve (9) has a valve body (36) having a seat (42) with whichcooperates a shutter (43) kept closed by a first spring (48) of substantially constant pressure, and by a second spring (49) varyuing in pressure during at least part of the stroke of the piston (7). The springs (48, 49) are helical compression types, and their pressures are summed on the shutter (43), which has a plate (44) and a stem (46). The first spring (48) is located between the valve body (36) and a flange (52) integral with a sleeve (53) which is fitted to the stem (46) in an adjustable position; and the second spring (49) is located between the plate (44) and the piston (7).</p> |
