US Patent 7775501 Pinch valve

A pinch valve has a hose-like valve member with a flexible peripheral wall adjacent to whose outer periphery two diametrally opposite pinch elements are arranged able to be moved toward and away from one another with a greater or lesser pinching of the peripheral wall while performing an operating movement athwart the valve member longitudinal axis. An annular actuating ring coaxially surrounding the valve member may act on the pinch elements for causing the operating movement. The actuating ring is placed in a working space surrounded radially from the outside by a peripheral valve housing wall and is able to be acted on by drive means separate from the actuating ring with a drive force controlling the actuating movement.