METC SOA Test Valve No. A-6: 6-Inch Rockwell Nordstrom Plug Valve

摘要

This report documents the results of ambient temperature static tests on a 6-inch Rockwell Nordstrom lubricated plug valve, ANSI Class 250, Rockwell Nordstrom Figure 265 (NETC SOA Test Valve A-6). The valve body and plug are of cast iron construction, with TFE coating of the plug surface. The objectives of the test were to determine baseline leakage rate and valve response time data. The test valve was cycled a total of 479 times during seven different runs. Run 07 was performed to establish baseline data for the new, factory-assembled valve. A total of 90 leak tests were performed during this run, while the total number of valve closure cycles at the end of this test period was 261. Leakage values remained within specification limits (6 scfm). Evidence of pressure being trapped in the plug was noted. Test Runs 07B through 07E were all performed in attempts to repeat the baseline leak rates results for Test Runs 07 and 07A after valve disassembly, inspection, and reassembly. This goal was not achieved as documented in the Procedure and Results section. Test Run 07F was performed after the valve plug and seat had been lapped to achieve metal to metal contact which is a different configuration than for prior tests which used plastic coating on the plug; both configurations used a lubricant seal, but different lubricants were used for each configuration. This arrangement yielded leak rate results which were 200% to 600% lower than the results of Test Runs 07 and 07A. However, intermittent leakage of unknown magnitude occurred which required maintenance of the valve including the addition of lubricant and increasing the load between plug and seat by tightening the packing gland. (ERA citation 04:050990)