ENS 50025
ENS Event | |
|---|---|
07:00 Apr 10, 2014 | |
| Title | Part 21 - Barton Model 288A and 289A Differential Pressure Switch Defect |
| Event Description | {{#Wiki_filter:Cameron Measurement Systems is reporting a defect affecting versions of the Barton Model 288A and 289A differential pressure indicating switches and spare switch assemblies for these products. The defect being reported is an out of specification concentricity issue with the roller that actuates the switches. This represents a switch setpoint repeatability concern.
Any additional safety significant issues that might be identified in our ongoing investigation will be addressed in subsequent advisories that will be published. If you have any questions please contact Chuck Rogers, Director of Quality and Safety, at (281) 582-9507 or Jim Greer, Engineering Manager, at (800) 291-3550.
The following information was excerpted from an e-mail: Cameron has performed switch setpoint repeatability testing which has verified that rollers, even those with out of tolerance run-out, can meet the published 0.25% repeatability specification as long as the roller moves freely along the switch operating cam. However, if the roller were to 'skid' or 'skip' on the cam, or rotate when the roller is off the cam due to vibrations such that the roller does not return to the exact same radial position when it's on the cam at the switch setpoint there may be a setpoint shift unless the roller has no run-out. A change in the switch setpoint could be as much as �0.32% even for the current run-out specification of 0.0003 inches. As such, given that Cameron could ship product with switch repeatability verified to be 0.25% during production testing and that an additional 0.32% could be possible due to the allowable roller run-out, a field performance of 0.57% is possible. Given wear and other uncertainties Cameron would recommend that a user consider a conservative field repeatability value for switch setpoint calculations. An important piece of information that was gleaned from the current testing effort is that switch repeatability testing is very dependent on the sensitivity of the calibration equipment utilized. Most calibration pressure sources and measurement displays have lags in the indication of the actual pressures applied that can cause errors and, even more critical, is the lag that occurs between the operator's response to the indication of the switch trip and the reading of the pressure source display. Cameron discovered that the observation of the indicator pointer (properly calibrated) is more accurate in verification of switch repeatability than any pressure source and electrical switch contact monitoring device we utilized. Once the switch setpoint is established, a pencil mark at this trip point on the indicator scale can be utilized to verify subsequent trip points. In conversations with customers that called to discuss the original Advisory concerns, Cameron became aware that some users may believe that the Model 288A and 289A switch performance is not impacted by changes in the environment where they are located. The Barton qualification for these products was a radiation augmented mild environment test program. A sample of products was exposed to 3 Mrads of radiation and then subjected to a 12G maximum seismic simulation. The products performed within specification for this limited testing at standard factory environmental conditions. In our opinion, field calibrations and switch setpoint testing should be performed at the same temperature conditions as expected when the instruments are required to perform their safety functions. Performance testing at one temperature may not necessarily ensure appropriate performance at another temperature. If you have any questions, want to place an order for a replacement instrument, switch actuation arm (with roller) or a switch and plate assembly, or want to begin the RMA process for an instrument factory repair please contact Mabel Loo, Customer Service Manager, Cameron Measurement Systems, City of Industry, CA at (800) 291-3550. Notified the R1DO (Dental), R2DO (Freeman), R3DO (Daley), R4DO (Werner), and Part-21 Group (via e-mail). }} |
| Where | |
|---|---|
| Cameron Measurement Systems Industry, California (NRC Region 4) | |
| Organization: | Cameron Measurement Systems |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+13.35 h0.556 days <br />0.0795 weeks <br />0.0183 months <br />) | |
| Opened: | Chuck Rogers 20:21 Apr 10, 2014 |
| NRC Officer: | Charles Teal |
| Last Updated: | Jun 9, 2014 |
| 50025 - NRC Website | |
Cameron Measurement Systems with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 504392014-09-09T07:00:0009 September 2014 07:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Report - Defective Barton Differential Pressure Switches ENS 500252014-04-10T07:00:00010 April 2014 07:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Barton Model 288A and 289A Differential Pressure Switch Defect 2014-09-09T07:00:00 | |