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Offshore Production Nearly 30% of Global Crude Oil Output

Wednesday, 26 October 2016  |  Chris Guy

Global offshore oil production (including lease condensate and hydrocarbon gas liquids) in 2015 was at the highest level since 2010, and accounted for...



Industry Headlines

Honeywell and Flowserve Collaborate on IIoT Solutions


Honeywell and Flowserve will collaborate to provide Industrial Internet of Things (IIoT) for industrial customers. The collaboration will be part of the Honeywell INspire program, Honeywell's joint customer development program for its IIoT ecosystem.

Honeywell and Flowserve have a long history of colla...


Train Named Executive President of Emerson Automation Solutions


Emerson recently named new senior leadership appointments to its Office of the Chief Executive who now report directly to chairman and CEO David N. Farr, and help develop and guide the company’s global strategies.

Michael H. Train’s new title is executive president of Emerson Automation Sol...


Offshore Production Nearly 30% of Global Crude Oil Output


Global offshore oil production (including lease condensate and hydrocarbon gas liquids) in 2015 was at the highest level since 2010, and accounted for nearly 30% of total global oil production. Offshore oil production increased in both 2014 and 2015, reversing consecutive annual declines from 2010 t...


New 2017 Construction Starts Increasing 5% to $713 Billion


The 2017 Dodge Construction Outlook predicts that total U.S. construction starts for 2017 will advance 5% to $713 billion, following gains of 11% in 2015 and an estimated 1% in 2016.

Manufacturing plant construction will increase 6%, beginning to recover after steep declines in 2015 and 2016 that refle...


Richmond Fed: Manufacturing Rises But Remains Sluggish


Manufacturing activity fifth district (MD, DC, VA, WV, NC, SC) remained sluggish in October, according to the most recent survey by the Federal Reserve Bank of Richmond. New orders and backlogs decreased this month, while shipments flattened. Hiring activity strengthened mildly across firms and wage i...


Consumer Confidence Retreated in October


The Conference Board Consumer Confidence Index, which had increased in September, declined in October. The index now stands at 98.6, down from 103.5 in September. The present situation index decreased from 127.9 to 120.6, while the expectations index declined from 87.2 last month to 83.9.



Water Hammer—Check It Out

Have you ever been in an area of the plant that had just shut down a pump, only to hear an explosive sound a few seconds later? The noise you heard was the pump check valve, accompanied by the water hammer, or reverse flow, that slammed it shut.

Multiple pump systems often use a check valve located between the pump and the discharge header. The purpose of this valve is to prevent backflow from the header to the pump when it is not running. Without the check valve the pump could actually spin backwards.

Depending on the system pressure, these valves can close with such force that they damage the check valve, the pump, and over time even the pump base. Most check valves require reverse flow to close the valve and once this flow momentum has started, it does not stop as quickly as the check valve closes. The result is water hammer, a very destructive force. According to Webster's: Water hammer: a concussion, or sound of concussion, of moving water against the sides of a containing pipe or vessel.

We have seen many plants overcome these laws of physics with the use of an "auto check," also known as a "butterfly check." This concept utilizes a pneumatic-operated butterfly valve, and relatively simple control logic in order to close the valve automatically, prior to shutting down the pump. This action avoids reverse flow, so that the back flow and water hammer never have the chance to develop.

The valves for these applications are typically high-performance butterfly valves with a pneumatic actuator. Accessories include a limit switch and four-way pilot solenoid with two adjustable speed controls. The speed controls restrict the airflow out of the cylinder in both directions, thus regulating the opening and closing speed of the valve.

Control logic for the auto check is simple. When the pump is not pumping, the butterfly valve is closed. When the motor start command is received, either locally or from the PLC, the pump motor is energized. Pressure builds up on the pump side of the auto check valve. A differential pressure switch senses pressure differential between the newly started pump and the header past the auto check. At some predetermined point-such as 1 psi, .5 psi. or .25 psi-the delta p switch makes contact on pressure increase. The switch is sealed in by a relay and energizes the solenoid valve, which opens the butterfly valve smoothly, aided in part by the speed control valves. When the butterfly valve is totally open, a limit switch is tripped and sends a valve-open status to the PLC.

When the motor stop command is received, the pilot solenoid is de-energized and the valve closes at a controlled rate, again aided by the speed controls. When the valve is completely closed the limit switch is tripped, which in turn shuts off the pump motor. This action eliminates water hammer by preventing any back flow from occurring.

BRUCE FENWICK is in technical sales for McJunkin Corporation, Harvey IL. Reach him via 708.225.3120 or at This email address is being protected from spambots. You need JavaScript enabled to view it..

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