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Last updateFri, 23 Sep 2016 2pm

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An Alternative Basics Education: Valve Ed Comes to You!

An Alternative Basics Education: Valve Ed Comes to You!

For the first time in the seven-year his...

Give Your Flow Meter a Happy Home

Give Your Flow Meter a Happy Home

Increased emphasis on the need to improv...

What’s in Store for the Construction Market?

What’s in Store for the Construction Market?

As was the case with many of the present...

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Industry Headlines

Pentair Valves & Controls Hosts Customer Appreciation Training Event

3 DAYS AGO
Pentair Valves & Controls Hosts Customer Appreciation Training Event

More than 200 representatives from Houston’s refinery, chemical and petrochemical industries joined Pentair Valves & Controls on Sept. 15 at its Pasadena, TX facility for a customer appreciation BBQ and training event . The presented seminars are a part of Valves & Controls’ Pentai...

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Mueller Water Products Recognized for Best Smart Water Solution

4 DAYS AGO

Mueller Water Products, Inc. received the 2016 Best Smart Water Solution award at the third annual Smart Water Summit in Palm Beach Gardens, FL. Mueller Water Products, who won this award for the second time, was recognized for smart technology solutions offered through its Mueller Co., Mueller System...

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Senate Overwhelmingly Passes Water Resources Development Act

3 DAYS AGO

The U.S. Senate recently passed the Water Resources Development Act (WRDA) of 2016 with a broad bipartisan vote of 95 to 3. This legislation not only authorizes critical U.S. Army Corps of Engineers projects that drive investment in navigation, flood management, and ecosystem restoration, it provides ...

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Alaska Railroad Prepares First U.S. Shipments of LNG

3 DAYS AGO

The Alaska Railroad (ARRC) will demonstrate its ability to safely transport liquefied natural gas (LNG) in intermodal LNG ISO containers from southcentral to interior Alaska during a month-long operational performance project in early fall 2016.

ARRC is the first railroad in the country to obtain permi...

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Manufacturing Growth Eases Again in September

2 DAYS AGO

At 51.4 in September, the seasonally adjusted Markit Flash U.S. Manufacturing Purchasing Managers’ Index (PMI) was down from 52.0 in August and pointed to the weakest improvement in overall business conditions since June. The latest PMI reading marked seven years of continuous growth across the ...

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Leading Economic Indicators Down Slightly in August

3 DAYS AGO

The Conference Board Leading Economic Index (LEI) for the U.S. declined 0.2% in August to 124.1, following a 0.5% increase in July, and a 0.2% increase in June.

“While the U.S. LEI declined in August, its trend still points to moderate economic growth in the months ahead,” said Ataman Ozy...

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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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