Control valve for contaminant-laden gases

Claim 1

A control valve for controlling and directing the flow of gases which may contain substantial entrained quantities of moisture, powdered solids, and granular solids, at moderate pressures and at high flow rates, comprising: a housing enclosing first and second axially aligned transfer chambers; a first external port connected to the first transfer chamber through a first valve port having a valve seat facing inwardly of one end of the first transfer chamber; a second external port connected to the first transfer chamber through a second valve port having a valve seat facing inwardly of the opposite end of the first transfer chamber; a third external port connected to the first transfer chamber intermediate the first and second valve ports; a third valve port connecting the first external port to the second transfer chamber and having a valve seat facing inwardly of one end of the second transfer chamber; a fourth external port connected to the second transfer chamber through a fourth valve port having a valve seat facing inwardly of the opposite end of the second transfer chamber; a fifth external port connected to the second transfer chamber intermediate the third and fourth valve ports; an actuator rod extending axially through the first, second, third and fourth valve ports and through both of the transfer chambers; a first poppet and a second poppet mounted in back-to-back relation on the actuator rod within the first chamber, the first poppet facing the first valve seat and the second poppet facing the second valve seat; a first retainer, mounted on the actuator rod, for limiting movement of the first poppet along the rod toward the first valve seat; a second retainer, mounted on the actuator rod, for limiting movement of the second poppet along the rod toward the second valve seat; first resilient biasing means biasing the first and second poppets toward their respective retainers; a third poppet and a fourth poppet slidably mounted in back-toback relation on the actuator rod within the second chamber, the third poppet facing the third valve seat and the fourth poppet facing the fourth valve seat; a third retainer, mounted on the actuator rod, for limiting movement of the third poppet along the rod toward the third valve seat; a fourth retainer, mounted on the actuator rod, for limiting movement of the fourth poppet along the rod toward the fourth valve seat; second resilient biasing means biasing the third and fourth poppets toward their respective retainers; and actuating means for moving the actuator rod axially between a first position, in which the first poppet engages the first valve seat and closes the first external port from access to the second and third external ports while the second retainer maintains the second poppet clear of the second valve seat so that the second and third external ports are in communication, and the fourth poppet engages the fourth valve seat and closes the fourth external port from access to the first and fifth external pOrts while the third retainer maintains the third poppet clear of the third valve seat so that the first and fifth external ports are in communication, and a second position in which the second poppet engages the second valve seat and closes the second external port from access to the first and third external ports while the first retainer maintains the first poppet clear of the first valve seat so that the first and third external ports are in communication, and the third poppet engages the third valve seat and closes the first external port from access to the fourth and fifth external ports while the fourth retainer maintains the fourth poppet clear of the fourth valve seat so that the fourth and fifth external ports are in communication.