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Industry Headlines

Industry Headlines

Cameron Signs Two Long-Term Transocean Service Agreements

-1 DAYS AGO

Cameron, a Schlumberger company, has signed two 10-year pressure control equipment management service contracts on behalf of Transocean valued at greater than $350 million.

The first contract calls for Schlumberger to manage Transocean’s Cameron risers in the Gulf of Mexico. This comprehensive ag...

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Total Valve Systems, Continental Disc/Groth Sign Distributorship Deal

40 MINS AGO

Total Valve Systems (TVS) announces a new distributorship with Continental Disc (CDC) and Groth Corporation. The two companies will provide customer service and relief & vacuum products to customers worldwide. Total Valve Systems will be responsible for sale and distribution to Oklahoma, Kansas, T...

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Plains All American Expanding Cactus Pipeline Capacity

-1 DAYS AGO

Plains All American (PAA) Pipeline, L.P. is expanding the capacity on its Cactus pipeline from McCamey to Gardendale, TX to approximately 390,000 barrels per day. The expansion will allow PAA to move increasing production volumes from the Permian Basin to Corpus Christi and other delivery points along...

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New Investments Spur Permian Oil Production Increase

1 DAY AGO

The Department of Energy (DOE) said on Tuesday that oil production in the Permian Basin could increase by 53,000 bpd by next month. According to the Energy Information Administration (EIA), that is the largest monthly increase in the region in a year.

“The EIA’s first shale oil forecast o...

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Industrial Production Sees Largest Rise in More Than Two Years

1 DAY AGO

Industrial production rose 0.8% in December, the largest increase since November 2014, after falling 0.7% the previous month. For the fourth quarter as a whole, the index slipped 0.6% at an annual rate.

Manufacturing output moved up 0.2% in December, as an increase in durable manufacturing outweighed d...

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IMF Raises U.S. Economic Growth Forecast

2 DAYS AGO

After a lackluster outturn in 2016, economic activity is projected to pick up pace in 2017 and 2018, especially in emerging market and developing economies. However, the International Monetary Fund (IMF) noted in its new World Economic Outlook, there is a wide dispersion of possible outcomes around ...

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Don't Overlook Linear Actuators on Gate Valves

At a recent sales meeting in California, I was surprised to discover the lack of awareness regarding linear valve actuators. In fact, one veteran of the valve industry remarked, "I didn't know you could operate a gate valve using compressed air and a linear actuator." Most folks in the valve industry are familiar with operating globe valves in this manner, but typically, multi-turn electric actuators have been used when automating gate valves. However, if the control application calls for faster stroke speed, mechanical failure position, precise positioning, or higher thrust, linear pneumatic or hydraulic actuators may be preferred.

The basic principle behind linear actuators is simple: a piston in a cylinder. This type of actuator is very simple and reliable; after all, it only has one moving part. Such a mechanical device has been around for more than 200 years. Pistons in cylinders first saw use in steam engines. Scotland's James Watt crafted the first good ones during the 1770s.

Attaching a linear actuator to a gate valve is fairly straightforward. First, the handwheel and drive nut comes off, exposing the threaded stem. Then, a coupling is used to connect the stem to the piston rod. This allows the linear actuator to move the stem up and down directly. The before-and-after pictures on the left and right, respectively, show the change from a manual valve to an automatic valve with the linear actuator.

Of course, the actuator is now producing "thrust" not "torque," and this is a critical specification for linear actuator design. As it turns out, the size of the cylinder is a function of the required valve thrust and the available supply (pressure x area = force). The cylinder is larger for a higher required thrust and a lower supply pressure. And since the actuator price increases as the cylinder size increases, engineers must verify that the supply pressure given is the highest available at the project site.

Moreover, if the calculated thrust is based on the maximum differential pressure rating across the valve (as defined by ANSI) and not actual operating design conditions, the specified thrust might be much higher than actual, which would require a larger cylinder and thus a higher price. Therefore, it is best to specify thrust based on actual design conditions to get the best price.

Linear actuators can be an effective automation solution for gate valves. As automation increases, so should our choices. That the linear actuator has proven reliable in many applications outside of the valve industry is testament to the enduring design of the pneumatic and hydraulic cylinder.

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