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Flowserve Announces SIL 3 Certification for Limitorque MXa Actuator


The MXa with the SIL 3 capable rating is designed to provide customers reliable actuation in critical environments without compromising their Safety Instrumented Systems

FlowserveDALLAS, June 11, 2012 — Flowserve Corporation (NYSE: FLS), a leading provider of flow control products and services for the global infrastructure markets, today 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, as well as Limitorque product experts, will be available at the ACHEMA 2012 Flowserve booth (Hall 8, Stand A64) June 18-22 in Frankfurt, Germany.

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.  

“The addition of a SIL 3 rating to the Flowserve Limitorque MXa underscores our commitment to providing products our customers can trust in their critical environments,” said Arnold Wallace, president, Flow Control Operations. “The MXa, with the SIL 3 rating, is designed to offer reliability and long service life in applications that require additional focus on safety.”

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 is key to achieving 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.  This ensures that the user does not need to utilize external SIL rated contacts to bypass the actuator’s internal contacts that are not SIL rated.

With more than one million Limitorque actuators installed around the world, serving a wide variety of applications, the global network of Flowserve Quick Response Centers and service centers are available to maximize plant uptime and profitability Flowserve customers.

For more information call +1 (434) 528-4400 or visit To see a complete listing of news, presentations and products for ACHEMA 2012, visit online at For more information, visit

About Flowserve

Flowserve Corp. is one of the world’s leading providers of fluid motion and control products and services. Operating in more than 55 countries, the company produces engineered and industrial pumps, seals and valves as well as a range of related flow management services. More information about Flowserve can be obtained by visiting the company’s website at

Technical Contact: Mike Mullin, director, investor relations, (972) 443-6636

Media Contact: Steve Boone, director, global communications and public affairs, (972) 443-6644


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