Monitored Dump Valves

CAT 4 / CAT 2 Monitored Dump Valves: The issue of safety in the workplace is becoming increasingly important for machinery manufacturers who are forced to sort out a mass of continuously evolving standards, the focal point of which remains the Machinery Directive. In order to ensure conformity of the machine, the manufacturer must verify that it meets the safety Requirements listed in the directive and guarantee compliance with the harmonised standards published in the European Union’s Official Journal and relating to the product in question.

SAFE AIR® Using the series of sturdy, reliable valves, such as those to ISO 5599/1, some special features have been added, such as the presence of a valve status diagnostic system and the creation of a double channel guaranteeing architecture redundancy. The simplest version features one electro pneumatically operated 5/2 monostable valve. It is common knowledge that when this type of valve is in the idle state (coil not energized), port 1 is connected to port 2, and port 4 relieves. When the valve is operated (coil energized), port 1 is connected to port 4, and port 2 relieves. When the coil is de-energized again, the valve is returned to the idle state (so port 4 relieves) by means of a spring that returns the spool to the home position. In the event of a failure, the spool may remain in the actuating position, even with coil de-energized, leaving port 4 pressurized.

To offset this problem, we have added a Hall effect sensor that reads the spool position. This means that when the valve is deactivated, the sensor is on, and when the valve is activated, the sensor is off. A status in whichthe sensor is off and the coil de-energized indicates a problem. To reduce the probability of risk during plant maintenance, the manual actuator mounted on the Cnomo electric control is the monostable type. The sensor inside the valve is available in the standard version with a 2.5m three wire cable (standard or ATEX certified) or with an M8 connector and a 300 mm cable. This valve, which is available in 3 sizes for the ISO 5599/1 series, isa category 2 component according to ISO EN 13849 and is suitable for use in safety circuits up to PL=c. For those requiring higher PLs, we have also developed a double channel version (redundant) that requires the use of ISO 5599/1 valves with a monitored coil arranged so that ports 2 are in parallel and ports 4 are in series. If just one of the valves de-energizes, port 4 relieves, so, even if one of the two coils remains blocked, the otherguarantees relief of the compressed air circuit. In this case, too, the presence of spool position sensors can be used to monitor the status. The double valve is also available in 3 sizes for the ISO 5599/1 series. It is a category 4 component according to ISO EN 13849 and is suitable for use in safety circuits up to PL=e. Both the single and the double channel valve come with: a Type Approval n° P13104/11/MC/nb issued by Bureau Veritas in accordance with EN ISO 13849 a certificate of compliance examination to the Machinery Directive 2006/42/EC CV **No. CV 002/10/2011 released by Bureau Veritas.

An overview of the standards can be found by clicking here  Image result for atex logo