Compressed air-actuated valve means

摘要

A compressed air-actuated valve means useful for attachment to devices used in chemical analysis wherein a piston actuates a suitably positioned slide member in the piston thrust direction. The slide member glides on a base member provided with spaced-apart holes that extend approximately perpendicular to the glide surface of the base member. The holes are connected to one another on the side of the base member facing the slide member via at least one appropriately arranged groove positioned in the slide facing the base member. Intake and discharge nozzles are connected with such holes on the opposite side of the base away from the slide member. The piston is a double-headed piston with each piston head being of a different diameter and each head being positioned at opposite ends of the slide member so that the slide member moves with the piston. The piston head with a smaller diameter is constantly biased with compressed air from a suitable compressed air source and the other piston head with the larger diameter is selectively biased with compressed air from the same source for controlling the slide movement.