Bellows driver slot valve
First Claim
1. A slot valve for creating an air tight seal to a vacuum chamber, comprisinga valve housing defining a valve chamber, the valve housing having first and second aligned openings for passage of air along a flow path from one side of the valve housing to the other side,a valve holder longitudinally reciprocable within the valve housing between a first holder position remote from said openings and a second holder position between said openings,a valve gate including a seal transversely reciprocable within said holder between a first gate position spaced from said openings and a second gate position sealing off one opening,a first actuator within the valve chamber for moving the valve holder between first and second holder positions, anda second actuator carried on the valve holder for moving the valve gate between first and second gate positions,the first and second actuators being within the valve chamber, andthe slot valve having a low profile.
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Accused Products
Abstract
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.
462 Citations
18 Claims
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1. A slot valve for creating an air tight seal to a vacuum chamber, comprising
a valve housing defining a valve chamber, the valve housing having first and second aligned openings for passage of air along a flow path from one side of the valve housing to the other side, a valve holder longitudinally reciprocable within the valve housing between a first holder position remote from said openings and a second holder position between said openings, a valve gate including a seal transversely reciprocable within said holder between a first gate position spaced from said openings and a second gate position sealing off one opening, a first actuator within the valve chamber for moving the valve holder between first and second holder positions, and a second actuator carried on the valve holder for moving the valve gate between first and second gate positions, the first and second actuators being within the valve chamber, and the slot valve having a low profile.
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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 comprising
a 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, and a 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, and means 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.
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16. A pneumatic slot valve for sealing off a vacuum chamber, the slot valve comprising
a valve housing defining a valve chamber, the valve housing having first and second aligned openings defining a flow path for the passage of air from one side of the valve housing to the other side, a valve gate movable into and out of seating engagement with the valve housing about the first opening, to seal off the flow path, a first pneumatic actuator within the valve chamber for moving the valve gate into and out of the flow path, the first pneumatic actuator comprising a linear pneumatic motor having a first working chamber for moving the valve gate into the flow path and a second working chamber for moving the valve gate out of the flow path, a second pneumatic actuator for moving the valve gate into seating engagement with the valve housing about the first opening, a valve holder for carrying the valve gate and the first pneumatic actuator, the second pneumatic actuator and the first working chamber of the first pneumatic actuator being in fluid communication with each other, the second pneumatic actuator including biasing means for unseating the valve gate, a high pressure source in fluid communication with the first working chamber for seating the valve gate, a low pressure source in fluid communication with the first and second working chambers of the first pneumatic actuator, for moving the valve holder into and out of the flow path, wherein the pressure necessary to overcome the biasing force of the biasing means is between the high and low pressures provided by the high and low pressure sources.
Specification