Compressed air is admitted through port 1 and flows through radial holes 2 into check valve 3, holding it against its seat, to which it is held preliminarily by helical spring 4. At the same time, the compressed air acts on the annular area outside the seat of valve 5. As the pressure increases, the force acting on this area becomes sufficient to overcome the resistance of spring 6 and the friction force, and valve 5 is shifted to the right. After the valve leaves its seat, the area on which the compressed air acts is drastically increased and the valve is reliably held in its right-hand position. Air entering port 1 passes out through port 8. The pressure at which the valve operates can be regulated by adjusting the force exerted by spring 6 using, for this purpose, threaded member 7. After valve 5 is opened, valve 3 is also opened.
$3629$SHP,Va$