VALVE FLOW TRANSISTION

摘要

1303316 Valves ROCKWELL MFG CO 7 April 1970 [10 April 1969 30 March 1970] 16297/70 Heading F2V A valve comprises a body having a chamber in which a closure member is movably mounted to control fluid flow between points adjacent the chamber and a flow transition region extending from at least one of the points to one end of the body and having boundary walls which diverge at an equivalent cone angle substantially in the range from 6 to less than 20 degrees and terminate in an abruptly enlarged section C, Fig. 4. When the valve has a flow passageway of non-circular cross-section the rate of change of cross-sectional area with length in the transition region determines the equivalent cone angle. The provision of the section C enables the overall length of the valve to be reduced with minimum pressure drop. A radius r having a value of up to one quarter of the diameter D of the conduit to which the valve is to be connected joins the section which has an equivalent cone angle of more than 60 degrees with the remainder of the transition region. The conical section C may be replaced by a recess 52 as shown in Fig. 5. An internal thread may be provided in a parallel bore at the outer end of the transition region to receive a threaded end on a conduit. Alternatively, the region may be terminated in a manner suitable for butt or socket welding to a conduit. The cone angle is preferably in the range of 10 to 14 degrees and the invention may be applied to plug valves with circular, rectangular or trapezoidal parts or to ball, gate or globe valves.