AJT design, supply and install 96” Automatic Self Closing Valve

AJT Site Services installation team, prior to installing the new ASCV

The original 96" Glenfield valve

Lifting the new valve and actuator from the transport

Refurbished Anti-Vacuum valves and paddle trip mechanism

Completed valve installation following commissioning and infill flooring installation

AJT were recently contracted to design, supply and install a new, fully bespoke 96” (2438mm) Automatic Self Closing Valve (ASCV), manufactured and supplied by VAG Group in Germany. This was to replace the existing 1950’s Glenfield valve and meet with current safety requirements. The newly installed unit features twin oil actuated open and counterweight close failsafe actuation, offering a safer alternative to the previously existing oil open/oil close servo. The new valve is capable of closing against almost 100cumecs to protect the low-pressure tunnel and power station against any ruptures or incidents.

Having already installed an identical 96” sister valve in 2019, AJT were experienced in what a project like this entails. Not only did the valve require replacing, but all the associated ancillaries, control system, access and guarding.

The valve was removed utilising the existing valve house crane and laid onto a custom-made skid frame (designed for its sister valve in 2019). The valve was then skidded from the valve house and lifted using a mobile crane on to transport.

Following removal of the valve, the pipeline underwent blasting and painting works. The two 35” Anti-Vacuum valves underwent a full strip down and refurbishment at AJTs Aberdeen based fitting facilities. The 10” bypass pipework and 12” drainage pipework was replaced with new stainless-steel pipework fabricated in-house by AJT. A new RIKO control valve was installed to provide the client with full regulation on Penstock filling rates.

Installation was the reverse of removal, with the skid frame integral in locating the valve within the valve house. The refurbished anti-vacuum valves were installed, along with bypass valve, pipework and drainage system.

Upon successful installation, AJT installed new infill flooring. This was designed by Envision Engineering and Design and fabricated in house by AJT. This provides access to the primary valve actuator and the integrated locking pins, allowing the user to lock the valve in either the open or closed position.

Commissioning activities were extremely successful, with handover of the valve completed to the client’s satisfaction.

AJT now move to the next phase of works which include installing fully designed PUWER compliant guarding around the counterweights and a new state-of-the-art flow monitoring system from our partner Rittmeyer of Switzerland.

For more information contact:

Tel No: 01224 871791

Email: info@ajt-engineering.co.uk

Website: www.ajt-engineering.co.uk

LinkedIn: https://www.linkedin.com/company/ajt-engineering-ltd/