DVG AUTOMATION - Holding Industrial · 2019. 5. 13. · DVG DVG Automation can provide actuators and control system fitted with several Partial Stroke Test systems to reduce the probability

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DVG

DVG AUTOMATION

MECHANICAL STROKE TEST DEVICE

DVG MST

Sales Office North and Latin America:

Holding Industrial S.A de C.V.www.holdingindustrial.com

Privada Guerrero 22-1 Col. Minerva Tampico, Tamaulipas C.P. 89110

http://www.dvgautomation.it/

mailto:[email protected]

DVG

DVG Automation can provide actuators and control system fitted with several Partial Stroke Test systems

to reduce the probability of failure on demand (PFD) and to increase the whole system reliability. The PST function will allow to partially operate the valve with no impact on the process. DVG can provide a wide range of PST systems such as: • Mechanical (local only) • Pneumatic/Hydraulic (local & Remote) • Electric (local & Remote) • Smart field device (local & Remote)

Partial stroke testing (or PST) is a technique used in a control system to allow the user to test a percentage of the possible failure modes of a shut down valve without the need to physically close the valve. PST allows actuator control elements (solenoids, positioners, relays, limit switches, etc.) to be fully tested.

PST is used to assist in determining that the safety function will operate on demand. PST is most often used on high integrity emergency shutdown valves (ESDVs) in applications where closing the valve will have a high cost burden yet proving the integrity of the valve is essential to maintaining a safe facility. In addition to ESDVs PST is also used on high integrity pressure protection systems or HIPPS.

What is the PARTIAL STROKE TEST?





according to any Customer requirement, this in order



https://en.wikipedia.org/wiki/Shut_down_valve

DVG

The DVG MST Device is a mechanical jammers inserted into the valve and actuator assembly that physically prevents the valve from moving past a certain point. These are used in cases where accidentally shutting the valve would have severe consequences, or any application where the end user prefers a mechanical device. • External device wafer mounted between the valve top-works and the actuator • Normally integrated in valve mounting hardware • The locking device mechanically limits the valve/actuator assembly stroke to 20deg (or as per specific Customer request) clockwise or counter-clockwise • Once disengaged, the complete assembly is free to travel for the entire stroke with no interference • Remote indication of PST status (engaged or not) can be provided as an option.

DVG MST Device can be provided on a brand new automated valve or supplied for field retrofitting to existing valve/actuator packages. The complete kit consists of a DVG MST Device, Engaging Key, a Stem Coupler adaptation between actuator and valve and a limit switch, when the remote indications of PST status is required.

DVG MST Device







DVG

The DVG MST Device has an internal cam which is disengaged during normal valve operation, and the actuator is free to stroke the valve on demand. To perform a partial stroke test, a user must insert the stainless steel engagement key into the DVG MST Device pivot seal. The screws limit the excursion, preventing the overrun.

The DVG MST Device engagement is carried out turning the key of 90 degrees clockwise. The Partial Stroke Test can be performed: - Manually, using a pneumatic hand valve - Remotely, using the remote control room electrical signal The test finally consists in:

- Verify the actuator movement. - Reset the solenoid valve – if any – or wait for confirmation from control room, in case of remote electric test. The DVG MST Device disengagement is carried out turning the key of 90 degrees counterclockwise.

DVG MST Device Operations







DVG

The DVG MST Device can be equipped with an external limit switch, mechanical or magnetic, to remote the PST status transmission to the control room.

Test assessment released by TÜV Rheinland are based on the following Test Specifications: IEC 61508: 2010 Part 1÷7 Functional Safety of Electrical/Electronic/Programmable Electronic Safety Related Systems IEC 61511-1: 2016, IEC 61511-2: 2003, IEC 61511-3: 2003 Functional Safety – Safety Instrumented Systems for the process industry sector

The assessment demonstrates the suitability for use of the DVG Automation mechanical partial stroke test device, model “Mechanical Stroke Test Device”, connected to an actuator used in a Safety Instrumented System for protective application up to SIL 3.

Remote PST status transmission

SIL3 Certification







DVG AUTOMATION - Holding Industrial · 2019. 5. 13. · DVG DVG Automation can provide actuators and control system fitted with several Partial Stroke Test systems to reduce the probability

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