Fluid Handling / Environmental Health & Safety / Safety Instrumented Systems

Flowserve Limitorque MXa Actuator Receives SIL 3 Certification

By Chemical Processing Staff

Jun 21, 2012

Flowserve has announced the availability of the Limitorque MXa electric actuator with up to a SIL 3 safety rating. The SIL 3 capable rating was obtained from Exida Certification Services after passing rigorous failure mode effects design analysis (FMEDA) and total time in service tests.

The MXa with the SIL 3 capable rating is designed to provide customers reliable actuation in critical environments without compromising their Safety Instrumented Systems (SIS). The MXa actuator carries the safety rating in a one out of two (1oo2) configuration, which requires two actuators and valves to be installed into a SIL 3 rated environment.

Flowserve Limitorque MXa has multiple features that make it advantageous for critical environments requiring SIL 3 certification, including LimiGard technology that automatically monitors the health of each coded signal and is designed to ensure that no component failure can cause the actuator to move unexpectedly.

Also a part of the LimiGuard technology, a unique absolute encoder designed with Built-in Self-Test (B.I.S.T.) capability. The B.I.S.T. feature confirms the sound operation of the encoder, ensuring the actuator is operating safely.

By comparing redundant signals, the LimiGard design of the encoder achieves a SIL 3-capable rating and contributes to the health of the actuator. MXa SIL 3-capable rating is a standard configuration that includes S1 and S2 contacts as well as the monitor relay. As a result, users do not need to utilize external SIL-rated contacts to bypass the actuator's internal contacts that are not SIL rated.

For more information, visit http://www.flowserve.com.