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Applications in Water Harvesting Systems

Applications in Water Harvesting Systems

Water harvesting in commercial projects ...

Safety Relief Valve FAQs

Safety Relief Valve FAQs

Companies that repair, test, maintain or...

An Update on U.S. Valve-Related Standards

An Update on U.S. Valve-Related Standards

It takes much time and effort by many pe...

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Industry Headlines

Group Asking Feds to Halt LNG Exports

Wednesday, 23 August 2017  |  Chris Guy

The Industrial Energy Consumers of America recently sent a letter to the Secretary of Energy on two LNG export demand scenarios. They argue that the O...

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Low Cracking Pressure in Chemical Processing Condensate Lines

Low Cracking Pressure in Chemical Processing Condensate Lines

Tuesday, 22 August 2017  |  Arie Bregman

Steam condensate is the liquid by-product formed when steam goes from the vapor state to the liquid state; this process occurs in a wide range of appl...

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Industry Headlines

Velan Names Duc Tran Vice-President, Engineering

-1 DAYS AGO

Velan Inc. has appointed Duc Tran as its new vice-president, engineering. Tran will be a key member of the company's senior management team and is succeeding Gil Perez, who has assumed a new mandate as vice-president, product technology and strategic initiatives. He will report directly to president...

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AIV and Gulf Coast Modification Opening NW Houston Facility

22 HOURS AGO

AIV, LP has announced plans for a new 320,000+ square-foot facility at NW Lake Drive, near Telge Road and Highway 290 in northwest Houston. The 32-acre construction site allows for the future expansion of up to 700,000 sq. ft. This facility will consolidate AIV and Gulf Coast Modification ’s curr...

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Group Asking Feds to Halt LNG Exports

-1 DAYS AGO

The Industrial Energy Consumers of America recently sent a letter to the Secretary of Energy on two LNG export demand scenarios. They argue that the Obama Administration’s “public interest” LNG export studies, which are still being used to justify LNG export approvals to non-free tra...

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Chemical Activity Barometer Shows Modest Slowing

17 HOURS AGO

The Chemical Activity Barometer (CAB) from the American Chemistry Council remained unchanged from July, continuing a modest deceleration of growth. The flat reading follows a 0.1% increase in July and a flat reading in June. Compared to a year earlier, the CAB is up 3.2% year-over-year, an easing fr...

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U.S. Factory Output Declined in July

4 DAYS AGO

Manufacturing output edged down 0.1% in July. The index for durables decreased 0.5%. Among durable manufacturing industries, with the indexes for primary metals and for furniture and related products each dropped more than 1%. The index for other manufacturing (publishing and logging) moved down 0.4%....

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Empire State Manufacturing Index Highest in Nearly Three Years

6 DAYS AGO

Business activity grew strongly in New York State, according to firms responding to the August 2017 Empire State Manufacturing Survey. The headline general business conditions index climbed fifteen points to 25.2, its highest level since September 2014. The new orders index rose seven points to 20.6 a...

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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.

—————

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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