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Metal Additive Manufacturing in the Valve Industry

Metal Additive Manufacturing in the Valve Industry

Metal Additive Manufacturing (AM) is a f...

The Past, Present and Future of Fire Testing

The Past, Present and Future of Fire Testing

Because so many of the applications wher...

Advancements in Blue Laser Scanning

Advancements in Blue Laser Scanning

As the industrial world continues to exp...

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Industry Headlines

LNG, Ethanol Sellers Buoyed by China Trade Talk

Wednesday, 23 May 2018  |  Chris Guy

“China's interest in reducing its trade surplus with the United States through increased energy imports could advance plans for U.S. liquefied n...

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Industry Headlines

Curtiss-Wright Supporting Ford-Class Aircraft Carrier Program

1 DAY AGO

Curtiss-Wright has been awarded a contract valued in excess of $85 million to provide main propulsion steam turbines and auxiliary equipment for the U.S. Navy’s Ford-class aircraft carrier Enterprise (CVN 80). The award was received from Huntington Ingalls, Newport News Shipbuilding (HII-NNS) ...

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Crane Celebrates Opening of New Plant in India

1 DAY AGO

Crane ChemPharma & Energy celebrated the inauguration of its newest location, an aseptic diaphragm valve factory in Satara, India. Crane invited hundreds of customers and industry stakeholders to participate in a day-long event complete with a tour of the new plant and luncheon held on May 10, 201...

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LNG, Ethanol Sellers Buoyed by China Trade Talk

4 HOURS AGO

“China's interest in reducing its trade surplus with the United States through increased energy imports could advance plans for U.S. liquefied natural gas (LNG) plants and ethanol sales, said analysts and energy executives involved in developing new LNG facilities.”

Reuters  reports th...

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Chemical Activity Up as Pace of Growth Slows

5 HOURS AGO

The Chemical Activity Barometer (CAB) from the American Chemistry Council (ACC), rose 0.1% on a three-month moving average (3MMA) basis in May to 121.9. The barometer is up 3.9% on a 3MMA compared to a year earlier. The unadjusted CAB showed a second consecutive month of gains, up 0.2% in May and also...

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Philly Fed: Manufacturing Activity Up in May Survey

1 DAY AGO

The Philadelphia Fed’s monthly survey indicate a pickup in growth for the region’s manufacturing sector. The indexes for general activity, new orders, shipments, and employment all improved from their readings last month. The indexes for prices paid and received continued to suggest price ...

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Manufacturers Are Boosting Hiring, Wages and Investment

2 DAYS AGO

A new survey from the National Association of Manufacturers (NAM) shows that manufacturers are keeping their promise after passage of the historic tax reform legislation by boosting wages, hiring and investment. The survey , released by Emerson chairman and CEO and NAM board chair David Farr during a ...

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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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