The reliable opening and closing of the base valve is performed by a pneumatic actuator developed by RIEGLER together with its customer WLS GmbH. This is activated via the compressed air system of the tank truck or tank car, whereby the cylinder is pressurized with compressed air and the piston inside starts to move. The piston rod, which is attached directly to the piston, presses on the valve seat of the base valve and opens it. A mechanical spring in the pneumatic actuator ensures that the base valve remains closed when no compressed air is applied and that none of the medium can escape. This way, the spring also ensures that the base valve closes in the event of a sudden pressure loss or line break and that none of the medium escapes into the environment. An emergency screw attached to the pneumatic actuator ensures that the base valve can also be opened manually without compressed air.

In order to meet the technical requirements at WLS, RIEGLER developed the pneumatic drive in two different housing materials: aluminum and stainless steel. The robust version made of stainless steel is used when external conditions are harsh and a high level of corrosion protection is required. The aluminum actuator, meanwhile, is the lighter and more cost-effective variant, provided that the external conditions allow it.

The solution developed by RIEGLER did not yet exist in this form on the market, as previously known actuators work as diaphragm cylinders rather than as piston cylinders. WLS received both the CAD data produced by RIEGLER and a product sample for approval in advance.

This project illustrates once again the versatility of compressed air and the multitude of different applications served by products from compressed air technology and pneumatics.

Technical data for the actuator
Working pressure max.: 10 bar
Piston diameter: 125 mm
Cylinder stroke: 32 mm
Use at ambient temperatures: – 40 °C to 50 °C
Weight: 14.3 kg (stainless steel version) / 7.8 kg (aluminum version)