Safety valves in the Safe-air® series

Always aware of the importance of safety, Metal Work has recently developed SAFE AIR® - a full range of products designed to safely relieve excess pressure in compressed air systems.

The ISO 5599/1 valves, which are intrinsically safe and reliable, have been upgraded with some distinctive features, including a diagnostics system that monitors the state of the valve and a double channel guaranteeing system redundancy.

The basic version is obtained from an electro-pneumatically controlled 5/2 monostable valve. When the coil is de-energized, the spool inside is held in the rest position by a spring; when the coil is energized, the spool moves to the drive position.

It may occur that, as the result of any failure, the spool remains stuck in the drive position even when the coil is de-energized, which leads to pressurisation of parts of the system that should be relieved. This problem can be overcome by inserting a sensor that reads the position of the spool in which a magnet has been inserted. This means that any failure can be detected by comparing the state of both coil and sensor.

A dual-channel version (redundant) has been developed with two independent valves mounted in series, whereby when one of the two spools gets stuck, the other ensures continuity of service. Also in this case, the spools are monitored using sensors.

These valves, which are available in 3 sizes to ISO 5599/1, are suitable for use in circuits requiring a degree of safety up to PL=c (single version) or PL=e (double version).

Both single and double valves are certified to EN ISO 13849 by an independent Notified Body.

Corrado Tamiozzo, engineer

Metal Work S.p.A.