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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...

Diagnostics for Commissioning and Startup

Diagnostics for Commissioning and Startup

Many facilities have found value in perf...

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Industry Headlines

Natural Gas-Fired Electricity Conversion Efficiency Grows, Coal Stable

Monday, 21 August 2017  |  Chris Guy

From 2006 to 2015, annual average heat rates of natural gas-fired electricity generators decreased 7% as heat rates of coal-fired electricity generato...

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Safety Relief Valve FAQs

Safety Relief Valve FAQs

Monday, 14 August 2017  |  Lyndon Garrick

Companies that repair, test, maintain or supply valves routinely receive inquiries from end users about safety-relief valves. Here are a few questions...

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Industry Headlines

Rotork Contracted to Supply UAE Oil Field

13 HOURS AGO

Rotork has received an order for 220 pneumatic actuators for the NASR Phase II Full Field Development Project in the UAE. The aim of the project is to increase the field's oil production capacity to 65,000 barrels per day (bpd) from the existing capacity of 22,000 bpd.

Awarded by Hyundai Heavy Industri...

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Forum Energy Technologies Acquires Multilift

4 DAYS AGO

Forum Energy Technologies, Inc. has acquired the stock of Multilift from Pelican Energy Partners, a Houston-based oilfield services focused private equity fund, and management. Based in Houston, Multilift manufactures the patented SandGuard and the Cyclone completion tools; products that extend the ...

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Natural Gas-Fired Electricity Conversion Efficiency Grows, Coal Stable

9 HOURS AGO

From 2006 to 2015, annual average heat rates of natural gas-fired electricity generators decreased 7% as heat rates of coal-fired electricity generators remained stable, increasing only 1%. Heat rates are calculated based on the amount of energy (measured in British thermal units) reported to the U....

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Executive Order to Speed Up Infrastructure Project Approval

4 DAYS AGO

President Trump signed an executive order intended to roll back “rules regarding environmental reviews and restrictions on government-funded building projects in flood-prone areas as part of his proposal to spend $1 trillion to fix aging U.S. infrastructure,” Reuters reports .

“Trump's...

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U.S. Factory Output Declined in July

3 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

5 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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Check Valves: Repair or Replace?

In today’s environment of shorter outage windows and shrinking maintenance budgets, the maintenance team should explore all available options when faced with a decision to repair or replace a valve.

As an example, let’s consider the choices when a damaged seat is discovered in a large bore, high-pressure swing check and/or reverse current valve in a typical steam system. Due to the difficulty in making a successful seat repair on this type of valve, the traditional approach has been to “limp” along until a replacement valve is available and an extended outage window is planned to allow the project.

 

The valve replacement approach is typically very costly because:

  • the new valve is expensive and usually has a long lead time
  • removal of the existing valve and installation labor and equipment is costly
  • the replacement process usually requires civil engineering to establish a rigging plan, restraint system and overall safe removal of existing valve and installation of the new one
  • the replacement process will more than likely require quality control management of extensive nondestructive examination and pre/post-weld heat treatment.

An Alternative
Most check valves are designed with a welded, integral seat located in a narrow valve throat and typically set at a 30-degree angle. This design makes repair of the seating surface virtually impossible using “off the shelf” machines and tooling. The lack of equipment to adequately make this repair has in the past left the end-user with one option to restore the integrity of the system—valve removal and replacement.

To remove and replace check valve seats reliably and in a cost-effective manner, the valve repair vendor must utilize custom tooling, procedures and techniques.

Utilizing this special tooling, craft personnel have performed numerous successful seat replacements on check valves, ranging in size from 12-inch NPS to 50-inch NPS. In this repair process personnel typically:

  • document “as-found” condition and dimensions
  • perform liquid penetrant testing (LPT) of the existing seating surface
  • machine-remove the existing alloy 21 hardfacing
  • perform LPT of the base metal (valve body)
  • perform base metal repairs if needed
  • install new alloy 21 hardfacing
  • machine a new seating surface to OEM specifications
  • perform liquid penetrant testing of the new seating surface
  • re-assemble the valve and “blue check” the seating surface to ensure 100% contact
  • document the “as repaired” critical valve dimensions.

These new techniques, along with the traditional valve repair procedures, provide the end-user with a refurbished component, restored to OEM specifications, in this critical application—without the time and expense required for a full valve replacement.

As with all mechanical components, routine maintenance and inspection is critical to keeping these types of valves in proper working order. Most end-users follow a carefully planned maintenance schedule; however, it is worthwhile to recap the elements of a successful program:

  • Schedule routine inspection and documentation of valve condition.
  • Perform non-destructive examination of valve seating surfaces and base metal pressure-containing components.
  • Maintain seating surface condition through a repair process such as the one described in this article.
  • Refurbish or replace worn valve components discovered during the inspection process.

If replacement of these types of valves does become necessary, contact an OEM to assist in the selection of the best valve for the application; make allowances for rigging and restraining the existing piping prior to valve removal; and take the opportunity to make any configuration changes needed to improve valve maintenance accessibility.

TY L. POTTER is Vice President of Operations, Southeast Valve, Inc.  located in Charlotte, NC. Reach the author at 704.588.0973.

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