The Air-Lock pressure static device is composed of a TP Pneumatic pressure switch combined with 2 x 3 way valves ND 1/4” in a single body. The Air-Lock pressure static device is mounted on pneumatic actuators when they need to be isolated from control devices (for example: positioners or electro-pneumatic distributors) in the event air pressure falls below the pre-determined operating safety point. The Air-Lock device consists mainly of a pneumatic pressure switch with an adjustable set point. This device synchronously drives the 2 x 3 way valves. The switching device operates immediately, even in the case of a gradual air-pressure decrease to the set value. The device will automatically reset after a failure when the line pressure is 1 bar greater than set pressure, to avoid instability around the device set point.