| 摘要 |
A spool valve for fluid systems includes a slidable spool (11) in a bore (14) in a valve block (10) having three ports (16, 17, 18) spaced axially along the bore (14) for control of fluid flow, the spool having three spaced O-ring seals (32, 33, 34) to correspond with the ports (16, 17, 18) and having a reduced diameter portion (29) between two of the O-ring seals (32, 33) and a pressure-equalizing conduit (35) connecting one end (13) of the spool (11) with the outlet port (17) of the valve. Small lands (30', 31') of substantially equal diameter to the spool (11) adjacent the reduced diameter portion (29) before the two O-ring seals (32, 33) provides restricted or throttled fluid flow prior to increased fluid flow via reduced diameter portion (29) during initial opening and closing of the inlet and exhaust ports (16, 18).
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