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Cleanliness Inspection of Hydraulic Actuators

Six years ago Oliver Valvetek changed its method of cleanliness inspection of hydraulic actuators and has not looked back.

Flush cleaning of actuators involves passing clean hydraulic fluid through an actuator at a sufficient flow rate to ensure turbulent flow is achieved.  Turbulent flow is when the Reynolds number exceeds 4000, the Reynolds number is calculated using the flow and the physical properties of the hydraulic fluid.

Originally during flushing of gate valve actuators with hydraulic fluid, in-line particle analysers were used to monitor the number and size of particles against a the NAS 1638 standard.  However, the analysers were poor at differentiating air bubbles and could give no indication as to the type of particles.

The NAS standard was superseded by ISO 4406 and SAE AS 4059F all of which clearly list the maximum contamination limits for cumulative particle counts.

For comparison and understanding of particle sizes, the analysis process and acceptable limits of SAE AS 4059F look at particulates in the process which are approximately 1/10th of the thickness of a human hair or 6um and bigger !!

In 2015, Oliver changed from in-line analysers to the far more sensitive optical analyser method.  The Pamas Fast Patch 2 Go system was chosen and provides the level of detail needed to ensure the cleanliness levels called for by our customers is met.  Since its installation over 6000 patches have been analysed.

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Oliver Valves has done it once again… “A Value Engineering Project” for a well known Middle East Customer

The Customer was using a combination of several valves and fittings to achieve the hook-up as per below picture on a Christmas tree. Oliver’s Middle East Sales Team worked hard with the End User, Christmas Tree Manufacturer, Integrator and in house Engineering to provide a value engineered product over a period of several months. Design reviews included Orientation of Valve Handles, ports, Pressure gauges and Clash Analysis of valves, handles and Pressure Gauges in a very confined space and of course weight reductions needed by the client.

This finally ended up in a Bespoke designed Double Block and Bleed with extra Test Port to give a much smaller, safer installation, avoiding extra leak paths, significant reduction in Weight (over 50%) thus reducing cost and eliminating vibrations and frequent replacements.

The complete supply is in 6Mo material, 10,000 psi rated with Handle Locking, Anti tamper vent facility, maintaining the minimum bore of 5mm. Supplied with fully traceable 3.1B materials for all wetted components.

So far we have supplied over 300 of these valves and this will now become the standard Hook Up for the future.

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Successful Client Cycle Test on Oliver Valvetek 1” Subsea Multi-turn Gate Valve

Traditionally the actuation of subsea valves is through the use of either manual operation, i.e. divers and remote operating vehicles (ROV) or hydraulic actuators.  Hydraulic actuators, as the name suggests, utilises pressurised hydraulic fluid acting on pistons to force the valve to either open or close.  Frequently using a spring to reverse the operation.  The supply of the pressurised hydraulic fluid can involve lengthy and costly umbilicals.  One alternative approach which is gaining more and more acceptance is for the use of subsea electrical actuators.

Over the past 3 years, Oliver Valvetek has supplied a number of 1” subsea multi-turn gate valves for operation by a particular client’s subsea electric actuators.  In a recent discussion between our client and their end user, a question was raised concerning increasing the rotational speed of the actuator to 40RPM and its effects on the Oliver gate valve.

To address this, our client performed a series of endurance tests on one of the production Oliver 1” gate valves.  The test program included a series of opening cycles with the valve under differential pressure, followed by 200 opening and closing cycles and finally a repeat of the opening cycles with the valve under differential pressure.  The objective being to review the torque to operate the valve through all the cycles noting any changes in torque profiles.

The 200 opening and closing cycles would be performed with no pressure in the valve in order to minimise resistance to the momentum of the rotational movement.

Overall the valve passed the test with consistent torques throughout all the cycles all being well within the design limits of the product.

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Michael Oliver, Chairman of Knutsford-based manufacturer Oliver Valves, has been named Manufacturing Entrepreneur at the Ernst and Young Entrepreneur of the Year Awards (North and Midlands).

The judges commended Michael on his “first-class business, built from scratch, debt-free and independent of the banks with a clear focus on values” and described the firm as “truly world­ class -a quality manufacturing business with global reach.”

Michael Oliver said: “It has taken more than 30 years of hard work, determination and innovation to get the business to where it is today and I think the judges recognised this.

It is also important to remember that building a business is not a solo achievement, and I owe a lot of thanks to my talented and hard-working colleagues at Oliver Valves.”

Michael will now go on to compete in the national awards, taking place in October. The awards were presented at Manchester’s Lowry Hotel and were judged by a panel presided over by North West Regional Development Agency’s deputy chair, Vanda Murray.