초록 ▼

A slot valve assembly (10) including a housing (11) having a central opening (19), a valve plate (32), a strongback (20) for carrying the valve plate, a pair of actuators (34, 36) for raising and lowering the strongback to position the valve plate over opening (19), and a second set of actuators (24

A slot valve assembly (10) including a housing (11) having a central opening (19), a valve plate (32), a strongback (20) for carrying the valve plate, a pair of actuators (34, 36) for raising and lowering the strongback to position the valve plate over opening (19), and a second set of actuators (240) for moving valve plate (32) into seating engagement with housing (11). Second actuators (240) are in fluid communication with the working chambers (48, 50) of the first pair of actuators (34, 36). First actuators (34, 36) are located within housing (11) to give the housing a much shorter height.

대표청구항 ▼

[ What is claimed is:] [10.] A control system for moving a valve gate longitudinally between first and second holder positions into and out of a flow path and transversely between first and second gate positions into and out of seating engagement with a valve seat, for sealing off the flow path, the

[ What is claimed is:] [10.] A control system for moving a valve gate longitudinally between first and second holder positions into and out of a flow path and transversely between first and second gate positions into and out of seating engagement with a valve seat, for sealing off the flow path, the control system comprisinga first pneumatic actuator for moving the valve gate between the first and second holder positions into and out of the flow path, the first pneumatic actuator including a first working chamber for moving the valve gate from the first to the second holder position into the flow path and a second working chamber for moving the valve gate from the second to the first holder position out of the flow path,a second pneumatic actuator for moving the valve gate into seating engagement with the valve seat,biasing means for biasing the valve gate to unseat from the valve seat, the second pneumatic actuator and the first working chamber of the first pneumatic actuator being in fluid communication with each other,a high pressure source for providing high pressure air to the first working chamber of the first actuator and to the second actuator, anda low pressure source for providing low pressure air to the first and second working chambers of the first actuator,the biasing means applying a force to bias the valve gate to the second gate position,the biasing means being overcome by pressure in the second between the high and low pressures,means to introduce low pressure into the first working chamber to move the valve gate into the second holder position and high pressure into the first working chamber and into the second actuator to overcome the biasing force of the biasing means and seat the valve gate and seal the flow path, andmeans to introduce low pressure into the second working chamber and vent high pressure from the second actuator and the first working chamber, to first cause the biasing force to overcome the pressure in the second actuator, then causing the valve gate to unseat, and then causing the pressure in the first chamber to drop below the low pressure in the second working chamber, causing the valve gate to move to the first holder position.