ENS 46403
ENS Event | |
|---|---|
05:00 Sep 15, 2010 | |
| Title | Part 21 Report - Limitorque Limit Switch Defect |
| Event Description | The following report was received via fax:
During the performance testing of our valves equipped with Limitorque SMB-00 we found that the limit switch contacts proved to be defective. These tests took place in July 2010. Flowserve was advised and sent in replacement parts that were installed by their representatives. The valve-actuator assemblies were cycled and proper operation was assessed. These valves have been shipped to Dominion Virginia. At the time we considered the issue isolated and did not pursue an in-depth corrective action response from the Supplier. Later in September when testing three valves equipped with Limitorque SMB-00 and two valves equipped with Limitorque SMB-2-06, we found again that the limit switch contacts were defective, exhibiting similar problems as found earlier in July. These valves are still at our factory, awaiting the response and corrective action from Flowserve. The limit switch boxes (4 gear train limit switches, 16 sets of contacts) appear to be identical on the two types of actuators mentioned above. Upon closer examination, we determined that construction and installation elements appear poorly controlled, resulting in unexpected failure to operate due to the contact blade (called finger base by the Manufacturer) not returning to a position where it can make contact again. This was documented internally on a Velan internal deviation report on September 3, 2010. We advised Flowserve of our findings on September 15 and issued a formal Corrective Action Request (CAR 25500-73903) on September 16, 2010, with a deadline for responding that expired on October 26, 2010. After a number of follow-ups, we managed to make contact with responsible personnel at Flowserve on October 29. An evaluation report (electrical continuity test performed on sample switch assemblies cycled 2000 times) was submitted to our attention by Flowserve. However, we determined that the test did not answer all our concerns and requested Flowserve to provide additional information. Currently the supplier is engaged in retrieving the defective parts from our facilities and performing additional examinations and tests. The Manufacturer expects to have all necessary tests, examinations and evaluations completed on or before November 19, 2010. Based on functional testing performed at Velan we determined that we have no record of similar defects on valve-actuator assemblies produced prior to these events, we therefore believe that the root cause is relatively recent but there is no way to know until Flowserve analyzes and evaluates the deficiency. This type of defect has the potential to affect other valve manufacturers who may have installed Limitorque actuators equipped with this type of limit switch but we cannot say if such deviation could create a substantial safety hazard.
On January 14, 2011, Velan received the final report from Flowserve concerning limit switches identified in this notification. Velan has accepted the conclusions in the report. The following is a synopsis of those conclusions: It was determined that producing a bend in the contact finger cannot occur during normal cyclic operation of the rotor. It is highly likely that the cause of the bent finger assemblies was due to the use of a flat blade screwdriver. A flat blade screwdriver can also exert enough force to damage the cotter pin hole in the spring stud. Based on testing and evaluations of all returned Velan switches and switches from Flowserve stock, a design deficiency has not been identified. Properly set switches will perform their intended functions. A maintenance update will be issued by Flowserve to guide the industry on any recommendations during their regularly scheduled maintenance outages. Notified R1DO (Newport), R2DO (Sykes), R3DO (Bloomer), and R4DO (O'Keefe). Notified Part 21 Group via E-mail. Notified NRR and NRO via facsimile.
Velan Inc. has issued the final report on this problem with no changes from the January 14, 2011 update. Notified R1DO (Bellamy), R2DO (McCoy), R3DO (Duncan), and R4DO (Clark). Notified Part 21 Group via E-mail. |
| Where | |
|---|---|
| Flowserve Quebec, Canada, (NRC Region) | |
| Organization: | Velan Inc |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+1306.03 h54.418 days <br />7.774 weeks <br />1.789 months <br />) | |
| Opened: | Victor Apostolescu 16:02 Nov 8, 2010 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Feb 8, 2011 |
| 46403 - NRC Website
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Flowserve with 10 CFR 21.21 | |
WEEKMONTHYEARENS 464032010-09-15T05:00:00015 September 2010 05:00:00
[Table view]10 CFR 21.21 Part 21 Report - Limitorque Limit Switch Defect ENS 454772009-11-06T05:00:0006 November 2009 05:00:00 10 CFR 21.21 Part 21 Report - Potential Failure of Bonnet Valve 2010-09-15T05:00:00 | |