Grit Suppression Ball Valve Assembly for Blast Pot
A ball valve with a typical pop-up head has a central vertical threaded insert for receiving a stem. A grit suppression sleeve is placed on the stem concentric with the stem. The grit suppression sleeve is generally a spool with a center hole fitting on the stem. The inside diameter of the stem is larger than the outside diameter of the suppression sleeve, permitting the sleeve to move freely on the stem and providing a controlled air way that will not carry grit, suppressing the grit that previously was exhausted through the main ball valve exit port.
1 . A pop-up ball valve assembly for use in connection with a blast pot having a generally closed top with an open/closing port on the top of the pot and a media inlet port provided by at the bottom of the pop-up ball being of the type having a generally spherical shape with a flat portion at the bottom of the pot and a substantially vertical stem defined by a substantially vertical open ended pipe, coupled for supporting the pop-up ball valve and permitting it to slide on the stem and engage and seal the port when the pot is under pressure and to drop and disengage the port when the pot is depressurized, the pop-up valve assembly comprising:
a. the pop-up ball having a tapped recess on the bottom face,
b. the elongated stem having an enlarged lower end and a threaded upper end, the threaded upper end mated with the tapped recess in the pop-up ball for receiving the threaded upper end of the stem,
c. a sleeve on the stem and freely movable along the entire exposed length of the pipe and able to engage the bottom wall of the ball valve at one end and be seated on the upper end of the vertical pipe.
2 . The pop-up valve assembly of claim 1 , the pot having a gasket for providing a seal between the ball valve and the sleeve when the sleeve is moved into contact with the ball, wherein the sleeve is responsive to the repressurizing of the pot to move upward with the general flow of air during repressurization and move down to the seat during depressurization.
3 . The pop-up valve assembly of claim 1 , wherein a lower end of the pot includes a pipe extending through wall and terminating in a vertical extension inside the pot, the pipe generally projecting upward and terminating at an open upper end, the pop-up assembly further comprising a sleeve having an inside diameter which is larger than the pipe outside diameter, permitting the sleeve to pass over the pipe, the sleeve further including a circumferential ring about its top end adapted to be engaged by the open upper end, the upper open end of the pipe serving as a seat for the sleeve.
4 . The pop-up valve assembly of claim 2 , further comprising an enlarged section of the stem, sized to fit in the open ended vertical pipe, the outside diameter of the pipe sufficient to provide stability to the assembly and including air pathways which are sufficiently sized to let pressurizing air pass through but too small to permit abrasive media particles.