The safety arrangement is basically a solenoid valve with a non-return valve built into it. A user requiring a safety arrangement may want to use a normally open Pinch Valve as a normally closed Pinch Valve. The safety arrangement works by keeping the Pinch Valve closed if there is a loss of air or electric on site. It lets air in, but not back out unless operated by the user.
Scenario 1
The Pinch Valve is closed and the user loses air on site. As the Pinch Valve is closed and the non-return valve will not let the air out then the Pinch Valve stays closed.
Scenario 2
The Pinch Valve is closed and the user loses electric on site. The Pinch Valve will stay closed because the air is still available and will not be able to escape.
Scenario 3
The Pinch Valve is open and the user loses electric on site. The Pinch Valve will still be able to close because there is still air available.
Scenario 4
The Pinch Valve is open and the user loses air on site. Unfortunately the safety arrangement system does not cover for this – the way to get around this problem is to have an air cylinder filled with air (air reservoir – amount of air required dependent on size of the Pinch Valve) that will shoot into the Pinch Valve. The air is held in this canister until it is required.
In the event where there could be a loss of both air and electric on site, if the Pinch Valve was held in the closed position it would stay closed. If the Pinch Valve was held in the open position, the air reservoir would close the valve from the canister.
See more Accessories for Pinch Valves.
