Constant flow rate control valve with low pressure drop start.

摘要

A constant flow rate control valve (10) is provided including a cup member (12) disposed in a flow passage through the valve (10). The cup member has an orifice (18) located in an end wall (14) of the cup member (12) and a plurality of side ports (22) in a side wall (16) of the cup member (12). The cup member (12) is moveable axially within the valve (10), with such movement being opposed by a resilient spring member (30) downstream of the cup member (12). The valve (10) includes a fixed retainer ring (26) in a valve body (24) surrounding the side wall (16) of the cup member (12) which blocks or exposes areas of the side ports (22) in response to movement of the cup member (12). Start up slots (34) in a side wall (36) of the valve body (24) are also blocked or exposed in response to movement of the cup member (12). Fluid pressure acting on the end wall (14) of the cup member (12) urges the cup member (12) against the spring (30), so that the retainer ring (26) exposes only that side port (22) area appropriate to the pressure being exerted and the cup member (12) exposes only that start up slot (34) area appropriate to the pressure being exerted.