Is your 3/2 solenoid valve redundant?

Of the vast number of 3/2 solenoid valves worldwide it is impossible to tell how many are piloting actuators that are part of ‘critical’ processes, i.e. processes that have an immediate impact on the safety or throughput of a system or plant. In many cases, any failure of a critical control valve can result in tremendous commercial losses until the cause of the failure can be addressed and in the wake of several high profile industrial incidents, the trend is for increased levels of control system complexity to achieve greater reliability.

Redundancy for all?

One way of achieving a reduced probability of failure is to double up on components that can fail. Solenoid valves can be combined in a 1oo2 configuration so that with two valves fitted and both coils energised, only one out of the 2 valves needs to operate correctly in order for the control function to be achieved. This only requires the mounting of a second valve, additional pipework and the control valve then has redundancy in the solenoid control circuit, but there are drawbacks:

For existing systems, it isn't a retro-fit solution.

An additional valve and piping may be difficult to fit in a restricted space.

Additional piping introduces more time required for the installation and depending on the piping material, can be a significant extra cost.

Extra piping can manifest in slower operation of the control valve through increased piping volumes, restrictions and pressure drops.

There is also the potential for increased air loss through additional potential leak paths due to the larger number of pipe connections.

Ask for a Redundant valve instead

The Nadi C90 series valve manufactured in Italy, offers 3/2 operation and 1oo2 redundant configuration in a single compact unit as well as:

3 port design - can be fitted in place of existing single 3/2 valves.

Compact design with IP65 or ATEX Exd coils.

No additional leak paths or air restrictions introduced.

Eliminates additional piping and installation costs.

Enables replacement of a solenoid coil while the other is still in operation.

Available in brass or 316 stainless steel bodies and suitable for ambient temperatures between -60 degress C and +60 degress C, this is a robust solution to an increasing concern and is much more cost effective than piping a second valve. For details on this and the soon to be released C91 series valve, please contact Red Dragon’s sales team.

Red Dragon Valves
Tel: 01443 772500
Email: sales@reddragonvalves.co.uk
www.reddragonvalves.co.uk

Published: 9th December 2013