12072016Wed
Last updateTue, 06 Dec 2016 8pm

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HR Professionals Gather at VMA Workshop

HR Professionals Gather at VMA Workshop

Human resources managers, executives rep...

Valves in a Cement Slurry Line

Valves in a Cement Slurry Line

Basically everywhere you look in modern ...

Triple Offset Butterfly Valves

Triple Offset Butterfly Valves

Since their introduction to the market m...

Digital Valve Control Leads to Increased Plant Availability

Digital Valve Control Leads to Increased Plant Availability

Surge is characterized by fast flow reve...

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Industry Headlines

Industry Headlines

Apollo Valves Combining with Shurjoint Mechanical Groove Systems

9 HOURS AGO

Aalberts Industries, parent company of Apollo Valves, has acquired 100% of Shurjoint Piping Products USA, Inc., Haohan Metal (Kunshan) Co. Ltd. and Shurjoint Metals Inc., effective November 29, 2016. The acquisition will be led by Aalberts CEO Glenn L. Mosack and sr. vice president global sales and ma...

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Largest Canadian Ethanol Producer Wins Emerson Reliability Award

9 HOURS AGO

Ethanol Greenfield’s Varennes, Quebec site won the 2016 Reliability Program of the Year at the Emerson Global Users Exchange in Austin. The site converts corn into fuel-grade ethanol, distillers grains, carbon dioxide and corn oil.

Emerson’s Reliability Program of the Year recognizes specif...

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New Pipeline Safety Rule Expands Excess Flow Valve Requirements Again

6 HOURS AGO

In October, 2016, The Pipeline and Hazardous Materials Safety Administration (PHMSA) announced a final rule that expands safety requirements for excess flow valves (EFVs) to multi-residential and commercial applications. That version of the rule covered the installation of EFVs in new or replaced se...

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New Wastewater Rules Preceded Reduction in Seismic Activity

8 HOURS AGO

“The rate of earthquakes in Oklahoma has dropped dramatically since late May, when the state limited wastewater injections into energy wells,” according to a statistical analysis from the Associated Press .

“This year, before the new rules went into effect on May 28, Oklahoma averaged 2...

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ISM: U.S. Manufacturing Expands at Best Pace in Five Months

1 DAY AGO

Manufacturing expanded in November as the Institute for Supply Management’s (ISM) Purchasing Managers Index (PMI) registered 53.2%, an increase of 1.3% from the October reading of 51.9%, indicating growth in manufacturing for the third consecutive month. A reading above 50% indicates that the ma...

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U.S. Adds 178,000 Jobs, Unemployment Rate at 4.6%

4 DAYS AGO

The unemployment rate declined 0.3% to 4.6% in November, and total nonfarm payroll employment increased by 178,000, the Department of Labor reported today. Employment gains occurred in professional and business services and in health care.

Employment in construction continued on its recent upward trend...

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The Human Factor in Valve Operation

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Worker safety, efficiency and the cost of operations, and most recently, new methods of control, are key focal points in operating valves. One factor that affects all areas is the role and level of human involvement in the processes.

THE CHOICES

Opening or closing valves can be completed either by manual input or automated devices driven by various energy sources. Manual operators are simple, inexpensive and require little peripheral planning beyond the installation and orientation of operators in the process line. Automated devices, on the other hand, require input energy systems, control systems, additional installation space and infrastructure for support, operation and maintenance.

Two concerns considered during selection of manual operators are the effort required to operate the valve and the number of turns some valves require. A lot of effort and a high number of turns can result in personnel fatigue, safety concerns, excessive time for operation and the need for multiple personnel. Also under consideration in selecting manual operators are the valve’s expected frequency of operation and the physical location of the operation, such as whether it might be high in a superstructure or situated in an inhospitable environment. Both also present challenges to humans.

Designers have to weigh all of these factors in their decision matrix to receive the most productive yet acceptable selection of how a valve should be operated. Two aspects that primarily define operator selection are human factors and economic factors. Human factors can be defined as the human capability to cycle the valve in a safe, timely and economically sound manner. These factors require considerations such as the work needed to be done (turns and rim pull) to operate the valve, the environment in which the valve is located, the time required to complete the task, and the health and safety of the personnel involved. Economic factors include the cost of the actuator as well as the cost of infrastructure, which could include wiring, controls system, power required and ongoing maintenance to support automated solutions.

THE SPECS INVOLVED

Specifications for the highest values personnel should exert on levers or handwheels to operate a valve are defined in the industry, with current API specifications limiting pull to 360 newtons (80 pounds-force). Mechanical advantage can be used to decrease the pull required to open or close the valve by increasing the length of the lever or diameter of the handwheel mounted on the valve. How­ever, the maximum lever length or handwheel diameter is also limited by industry specifications.

As valve torque increases, maximum limits imposed by industry standards result in levers transitioning to gear units to increase mechanical advantage. However, this increase in mechanical advantage comes with the disadvantage of increasing the number of turns to move the valve across the full stroke distance.

The higher number of turns results in longer time required to cycle the valve at a constant number of revolutions per minute. With significant gear reduction, the number of turns required for full cycle can number in the hundreds. This increased number of turns leads to a greater opportunity for accidents or injury to personnel due to repetitive motion and fatigue. Companies will limit the rim pull and number of turns to reduce the risk. Once established limits are exceeded for turns, the valve is generally required to be automated.

Communicating what human factor limits might be imposed on valves can provide suppliers the opportunity to recommend the best value of operator for manual valves. Until recently, the valve industry was limited to levers, bevel gears and traditional worm gears for manual cycling. Once these devices exceeded worker safety limits, a valve purchaser’s only choice was to select an automated solution. However, new devices available in the marketplace extend the range of manual operators. These devices can reduce initial capital costs, reduce site design complexity and minimize operating expenditures. The devices include high-efficiency gear operators and portable drivers coupled with well-designed arrestors.


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