Control valve

Claim 1

An easily assembled and disassembled control valve comprising: (a) a main bifurcated case including an upper case and a lower case, joined together; (b) a device for converting angular motion into linear motion comprising a ball screw which includes a threaded shank and a nut associated therewith and disposed therearound, which nut is fixedly secured to a sliding body mounted axially with respect to said threaded shank and nut in said lower case, such that said sliding body is movable longitudinally in said lower case but is prevented from rotating within said lower case, wherein said upper case has a bottom wall separating said upper case from said lower case and supports said threaded shank by way of an upper thrust bearing; (c) a reversible electric pulse motor affixed to a free end of said upper case, having a rotating shaft extending into said upper case, and wherein said threaded shank of said ball screw extends into said upper case from a lower end of said upper case opposite said free end and adjoining said lower case, and wherein said rotating shaft and said threaded shank are joined together by a coupling in said upper case, wherein said upper and lower cases being joined together and said pulse motor being affixed to said upper case by a plurality of elongated bolts, each bolt extending through said pulse motor and upper case to be anchored in said lower case, such that said pulse motor and upper case are removable from said control valve by simply removing said elongated bolts; (d) a valve stem removably attached to a lower end of said sliding body; (e) a valve body having an inlet, an outlet and a channel, terminating in a seat, connecting said inlet and outlet, said valve body being removable connected to said lower case; (f) a stuffing box separating said valve body from said lower case and through which said valve stem projects, said stuffing box being removably attached to said lower case by threads on a bottom wall of said lower case cooperating with threads on a circumferential outer surface of said stuffing box; and (g) a tapered needle plug affixed to the end of said valve stem projecting into said channel and sealable at said seat, wherein said nut, said sliding body, said valve stem and said tapered needle are also supported by said bottom wall of said upper case.