Patent attributes
A unitary slot valve actuator is in a vacuum body between process and transport modules. A separate valve is provided on the unitary actuator for each of two valve slots, each slot being closed or opened according to the position of the unitary actuator. The separate valves allow a vacuum condition to be maintained in the transport module while an adjacent process module is open to the atmosphere for servicing. Access to both open valves for servicing is by centering the unitary actuator to hold both valves open, but not vertically-spaced, relative to the slots. The open valves are easily reached by a service worker through an access port. A computer workstation operates a controller for the slot closure, and for moving the unitary actuator and the valves from the open and centered position, away from the slots to expose seal surfaces around the slots for cleaning.