FIELD: mechanical engineering. SUBSTANCE: assembled on mounting plate is housing with passages for supply and discharge of working medium. Spring-loaded valve unit with shut-off members equipped with seals is mounted in housing. Two covers are secured on housing with seals laid between covers and housing. Spring is located in one of covers. Pusher hollow on one side is rigidly connected with guide which holds ring made of antifriction material. Second cover is provided with axial hole. Pusher and guide are arranged inside cover for engagement of hollow end of pusher with valve unit and extending of opposite end through hole in the cover. Passage located in housing on side of spring is brought in communication with atmosphere. Passage located on side of pusher is connected with vacuum and passage located shut-off members is connected with pneumatic system. EFFECT: enhanced reliability. 3 cl, 2 dwg
