Simple and fast test can be conducted online without risk of impacting production.
SPRING HOUSE, Pa. (October 5, 2004) - Siemens Energy & Automation introduces a Partial-Stroke Valve Testing package to ensure the safe and reliable operation of emergency shutdown valves. In response to a need for reduced test intervals without interrupting operations, Siemens has developed an on-line partial-stroke testing solution for pneumatically operated emergency shutdown valves. The fast test is simple to perform and can be conducted online without risk of impacting production. Additionally, the use of diverse technology to actuate the valve reduces the chance for common cause failures.
The package uses the SIMATIC Safety System, S7-400F, in conjunction with a smart valve positioner, to test pneumatically operated shutdown valves by partially closing the valve, proving the valve moved to the commanded position and resetting the valve to the open position. The test is safeguarded by a failsafe discrete output which serves as an independent method of driving the valve to its failsafe position. The analog output to the positioner, in combination with the discrete output, provides two separate ESD signals to the actuator, resulting in a 1oo2 "failsafe" voting arrangement. Independent certification for this package to IEC 61511 is currently under review.
With the availability of on-line partial-stroke testing, a positive move can be made toward predictive maintenance, as opposed to preventive maintenance.
Furthermore, maintenance costs can be decreased, and overall instrumented system performance can be improved.For more information: www.sea.siemens.com