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Last updateFri, 29 Apr 2016 5pm

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Food and Beverage Processing

Food and Beverage Processing

When wandering the grocery store aisles,...

Variable Frequency Drives in Electric Actuators

Variable Frequency Drives in Electric Actuators

Electric actuators are vital for operati...

Braided Packing: An Old Technology with a Modern Twist

Braided Packing: An Old Technology with a Modern Twist

Compression packing is the primary metho...

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Industry Headlines

Rotork Acquires Mastergear from Regal Beloit

2 HOURS AGO  |  Chris Guy

Rotork has acquired the entirety of Mastergear’s business and assets from Regal Beloit Corporation for $25 million on a cash-free and debt-free ...

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Industry Headlines

Rotork Acquires Mastergear from Regal Beloit

2 HOURS AGO

Rotork has acquired the entirety of Mastergear’s business and assets from Regal Beloit Corporation for $25 million on a cash-free and debt-free basis and a value of inventory that will be finalized at the end of a transition service agreement.

Mastergear will become part of Rotork's Gears divis...

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Emerson Opens New Helix Innovation Center

23 HOURS AGO

Emerson announced the launch of its “Helix” initiative, including the opening of The Helix innovation center, an industry-first, $35 million hub dedicated to advancing research and education for the global heating, ventilation, air conditioning and refrigeration (HVACR) industry. The new ...

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Energy Sector Weighs on Construction Starts

23 HOURS AGO

At a seasonally adjusted annual rate of $660.5 billion, new construction starts in March receded 1% from February’s pace, according to Dodge Data & Analytics. Total construction starts had jumped 13% in February, led by a huge gain for the electric utility and gas plant category. The dolla...

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Chevron Investing Billions in The Permian Basin

2 DAYS AGO

At Chevron’s annual security analyst meeting last month, chairman and CEO John Watson said that his company plans on investing billions into oil & gas projects in the Permian Basin.

According to the Hobbs News-Sun , Watson predicted they could be pumping up to 350,000 barrels a day out of West ...

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House Passes Bill To Lower Import Tariffs On Manufacturers

1 DAY AGO

This week, the House voted 415-2 for the American Manufacturing Competitiveness Act of 2016. The bipartisan, bicameral bill reforms the way Congress considers legislation for suspending tariffs on products not made in the U.S., what some are calling, “manufacturing tax breaks.” The legis...

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Texas Manufacturing Index Shrinks More Than Forecast

3 DAYS AGO

Texas factory activity increased for a second month in a row in April, according to business executives responding to the Texas Manufacturing Outlook Survey. The production index, a key measure of state manufacturing conditions, rose from 3.3 to 5.8, suggesting a slight pickup in output growth.

Perce...

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A Guide to Valve Cleaning and Specifications

Most of the time we only require that valves be free of basic dirt and debris before they are put in service. However, occasionally service requirements dictate that all traces of oil, dust and grease be removed. A prime example is valves to be used with oxygen. In that case, even a small speck of oil in a 100% oxygen environment can create a devastating explosion. One tiny metallic sliver could cause a minute spark, which is all that would be required to trigger the destruction.

 

Other media that require this level of cleanliness include numerous other pure gases, chlorine, paints and some chemicals. What all this means is that a standard, off-the-shelf valve cannot be used in these media unless it has been properly processed before installation. Decades ago, achieving this degree of cleanliness required the use of vapor degreasing machinery filled with a chlorinated solvent such as trichloroethane. These chemicals worked marvelously to clean, but they have been proved to be carcinogens, so their industrial cleaning usage has all but disappeared. In their place, environmentally friendly aqueous-based cleaners, such as Simple Green, have become the norm.


Follow the Specs

Even with the use of the right cleaning agent, however, it takes more than a simple “wash behind the ears” to ensure that a valve is clean enough for intended service. This is where cleaning standards and specifications come in. Fortunately, there are very good specifications to guide valve assemblers and technicians in the cleaning process. In fact, the American Society for Testing and Materials (ASTM) has a committee that works solely on specifications for oxygen service applications: Committee G04. This group produces ASTM G93, “Standard Practice for Material and Equipment Used in Oxygen-Enriched Environments,” which is a very thorough document and an excellent reference for valve cleaning procedures.

The Compressed Gas Association (CGA) publishes another often referenced cleaning standard: document CGA G-4.1, “Cleaning Equipment for Oxygen Service.” Many end-users that don’t have their own specific procedure reference the CGA 4.1 standard. The Manufacturers Standardization Society (MSS) also recently created a valve cleaning standard, MSS SP-138-2009, “Quality Standard for Oxygen Cleaning of Valves & Fittings.” This document is derived from many end-user specifications as well as CGA G-4.1. For chlorine service cleaning, the Chlorine Institute references cleaning procedures in its document: “Piping Systems for Dry Chlorine.”

The common denominator for all the cleaning standards is removal of all traces of oils, grease, dirt and other contaminants. The methods prescribed include scrubbing, ultrasonic cleaning, pressure blasting and sand blasting.


Rust Elimination

One important issue in cleaning is the presence of rust on carbon steel components after cleaning. With any of the prescribed cleaning processes, the protective film or rust preventative on the steel is removed, which exposes the metal to rapid oxidation, a problem that is particularly acute in humid environments. In many cases, a light blush of rust is acceptable, but gross deposits would not be. As a result, cleaning may need to be performed in a non-humid area. Additionally, carbon steel valves and components that have been cleaned require some form of corrosion protection—either desiccant bags inserted in the valve bore or an exterior wrapping with vapor phase inhibitor paper, or both.

After valves have been carefully cleaned and checked for proper cleanliness, they are usually put in protective heavy-gauge plastic bags to ensure they stay clean until installation.

Cleaning of valves is a straight-forward process that requires some diligence and quality control. However, guidance is available from various standards and specifications. Also, since the valves must be disassembled for most cleaning procedures, it’s important that the personnel involved be familiar with proper disassembly and re-assembly of the valves to be cleaned.

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Greg Johnson, a contributing editor to Valve Magazine, is president of United Valve (www.unitedvalve.com), which offers factory-authorized valve modifications and repair from its Houston, TX facility. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..

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