Performance Tests - PTFE Clamp Valves The tests described in this section illustrate the capabilities of the PTFE Clamp Valve. Such tests were run to qualify the valve design and occasionally similar tests are run as a periodic control of current production. Except as noted, they do not constitute test requirements for any specific production order. Positive Shut-off Test This test is performed on every valve manufactured. The valve is closed using the specified torque and 225 psi air is applied for 1 1/2 minutes. Zero leakage is required. The 6" and 8" valves with 3:1 gear boxes are tested at 75 psi, which is the maximum pressure recommended for this valve-gear box combination. Structural Proof Pressure Test This test is performed on every tenth valve manufactured. The valve is fully opened and 350 psi air is applied for 5 minutes. Zero external leakage is required. High Pressure Flex Life Test The valve is cycled from full open to full closed for 10,000 cycles. Of the total cycles, 5000 are run at room temperature and with 225 psi pressurized oil circulating in the valve test loop. The remaining 5000 cycles are run at 400°F oil temperature (350°F for the 6" and 8" sizes) and a pressure of 150 psi. At the completion of the test the valve is degreased and pneumatically checked for shut-off and proof pressure per the above tests. Low Pressure Flex Life Test This test is run for 5000 cycles at room temperature and 5000 cycles at the maximum rated temperature, as above, except that the internal pressure is maintained at 30 psi throughout. Cleaning, Proof testing and Shut-off tests are run as for the High Pressure Flex Life test. Steam-Cold Water Cycling Test This test produces thermal shock loading by alternately applying high temperature steam followed by cold water to a loop containing the test valve. The steam is supplied at 125 psi (353°F) and the water is taken from the cold water tap, but is limited to a maximum temperature of 80°F. A cycle consists of steam flow for 165 minutes, a 2-3 minute drain period and then cold water flow for at least 25 minutes. The water is drained for 3-5 minutes and then the cycle is repeated. A test consists of 50 cycles run with the valve fully open, 30 cycles at 1/2 open, and 20 cycles at 1/4 open. Proof testing and shut-off tests are run to confirm that the valve is not impaired. Blister formation on the PTFE I.D. is acceptable. Vacuum Test The ability of the valve to operate under vacuum conditions and be able to completely seal against a vacuum is demonstrated by the Vacuum test. Initially, the valve is checked by having the valve lock-in a full vacuum of 29.92" Hg. The vacuum is monitored for possible decay for 5 minutes. The valve in the full open position is then placed in an oven at maximum rated temperature, (400°F for 1" thru 4", 350°F for 6" and 8") for a 3 hour temperature soak while full vacuum is continually applied. After the soak period, the valve is then cycled open-close-open ten times. This cycling is repeated at 30 minute intervals for a total of 100 cycles, all the while the high temperature and full vacuum are maintained. At the completion of the cycling the valve is tested for vacuum decay at room temperature as in the initial test above. Room Temperature Burst Test This test proves that the burst capability of the valve is at least 4 times the rated pressure at room temperature. The valve, in the full open position is filled with a suitable test fluid. The pressure is increased at a rate not exceeding 1000 psi/min. until a burst is obtained. The minimum acceptable burst pressure is 900 psi for all sizes. High Temperature Burst Test This test is run at elevated temperature to demonstrate the burst capability is 600 psi at a temperature of 400°F for all sizes. The test is run with the valve fully open. The temperature is built up either by an oven soak for 3 hours or fluid conditioning by circulating 400°F oil through the valve for 3 hours. The valve is then tested by increasing the fluid pressure at a rate not to exceed 1000 psi/min. until burst is obtained. Nitric Acid Exposure Test This test is representative of the type of testing performed during the development of the valve. It demonstrates the ability of the valve to withstand extreme corrosives and function for thousands of cycles without a loss of performance capability. The valve is set up with a power actuator in a test loop flowing 60% HNO3 at 200°F and 50 psi. The ambient temperature is between 70°F and 100°F. A cycle is defined as moving from the full open position to the full closed position, holding for 15 seconds and then returning to the full open position. The valve is cycled 10,000 times. At the completion of the cycling the valve is cleaned and tested with air for shut-off at 225 psi and proof at 350 psi. The valve is full disassembled and inspected for physical damage.