New check valves by HAWE Hydraulik offers better error elimination

Twin check valve with hydraulic release (left) and check valve (right). Both are available for system pressures up to 700 bar.
Photo by HAWE Hydraulik SE plc

Pilot-operated check valves are indispensable components for hydraulic systems in machine tools. If they work reliable the risk of malfunctioning hydraulic consumers is reduced. With four types of check valves the Munich-based HAWE Hydraulik SE now offers an error elimination certificate for two error assumptions pursuant to the safety standard DIN EN ISO 13849-2:2003.

When assessing the risk to hydraulic functions, manufacturers of stationary machine tools can now assume error elimination for pilot-operated check valves of the types RH, DRH, RHC and RHCE. This applies to the error assumptions according to Annex C4 of ISO 13849: independent changing of the starting position without input signal, “Not Closing” and “Not Fully Closing”. In practice this means for example that the valve control for hydraulic workpiece clamping in machining centers can be significantly simplified because additional monitoring functions are omitted.

According to the DIN EN ISO 13849 standard the safety level of a machine must be assessed. The certificate from HAWE Hydraulik makes calculation the risk assessment easier and thereby helps reduce development expenses, as the structures for eliminating the listed faults need not be built.

To eliminate error assumptions, HAWE Hydraulik tested according to the FMEA method and made extensive analyses of possible faults and their impact on the machines’ safety. In addition, the company conducted a statistical assessment of service reports by precisely analyzing the failure causes of the returns received over the last five years.

For more information, please visit http://www.hawe.de.

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