That’s Not What It Was Designed For!

Ten years or so ago, Nadi srl in Italy took their solenoid valve technology and applied it to a customer requirement for pressure vessel integrity testing.

The result was the VCT9367 tandem solenoid valve as pictured here with two 100bar rated 2/2 normally closed solenoid valves in series mounted in a common body.

Block & Bleed
The client had tried 3/2 solenoid valves but had problems with maintaining pressure as the valves changed state and needed to be able to apply and release pressure independently using one compact unit. On the resulting VCT9367, the first valve applies pressure to the vessel through the outlet port that connects to the inlet of the second valve which is closed.

When the vessel test period was complete, the first valve was closed and the second valve opened to vent the gas for recycling. This design proved very successful in this application and was made available with brass or stainless steel bodies and options for safe area or ATEX Exd versions.

Recirc & Spray
More recently Red Dragon had a request for a similar duty on high pressure cold water. Many pressure wash systems use a pump feeding a demand valve where the pump has to build pressure while the valve is open and in this automated washing system, this would result in inconsistent cleaning.

In order to overcome this problem, the pressure line needed to be constantly recirculating back to the pump so that the draw off was always at the same pressure. It could be done with separate valves but this takes up more space and time for the installation. The other downside to separate valves was the distance from the recirculation line to the demand valve needs to be as short as possible to prevent pressure losses.

We trialled the VCT9367 in this application using a different configuration from that it was designed for and it worked perfectly. The first valve controls the output from the pump and when open connects to the recirculation line for the manifold. The second valve is the demand valve that permits water to the spray nozzles at a constant pump pressure.

By understanding the clients’ needs and the capability of the Nadi valves, Red Dragon was able to solve their problem and enhance the quality of their product successfully using an existing valve but contrary to its original design intent.

Tel: +44 (0)1443 772 500
Email: sales@reddragonvalves.co.uk
eb: www.reddragonvalves.co.uk

Published: 13th May 2016