| 摘要 |
A pressure reducing valve comprises a valve body (2) with an inlet (8) and an outlet (9) and a pressure reducing assembly (4,5) providing communication therebetween. The pressure reducing assembly comprises an outer tubular guide element (4) with a plurality of axially spaced inner guide formations (13, 14, 15, 16) and an inner flow control sleeve (5) slidable on said guide formations to define within the pressure reducing assembly a plurality of axially spaced chambers (20, 21, 22). The flow control sleeve (5) has a plurality of axially spaced sets of pressure reducing orifices (24, 25, 26) positioned such that in a first position of the flow control sleeve each chamber (20, 21, 22) registers with a set of said apertures (24, 25, 26) and in a second position of the sleeve the orifices are closed by the guide formations (13, 14, 15, 16). Additionally the pressure reducing assembly has a plurality of flow transfer passageways (17, 18) arranged to allow fluid to pass serially through said sets of pressure reducing orifices and said chambers from the inlet (8) to the outlet (9), whereby pressure reduction is effected in a number of stages. |
