Archive: Jun 2016

Ways to Maintain Your Control Valve Maintenance Budget

Today’s power generating plants face two major factors: reduced maintenance budgets and competition from renewable energy.

Maintenance budgets are tight, often forcing managers to put off problems that really require serious attention. The increasing popularity of renewable energy sources is diminishing the demand for traditional fossil power generation.  As a result, plants are regularly operating below intended capacity or coming off line.

Base-loaded fossil power plants operating at reduced generating capacity or become cycling units places heavy demand on control valves in ways they may not have been designed to operate. When control valves operate below their intended capacity they operate closer to their sealing surfaces than intended.

This reduced flow rate greatly increases the velocity within the valve and increases potential erosion. This is especially true on Feedwater and Boiler Feedwater Pump recirculation control valves. Plant managers can begin minimizing control valve seat erosion and reducing subsequent maintenance costs by reviewing sizing of control valve internal trim.

Trending data is excellent for determining actual operational conditions versus what was recommended in the valve specifications.

Control valves are designed with the following factors in mind:

• Fluid type
• Upstream pressure
• Downstream pressure
• Flow rate
• Temperature

Next, plant engineers, procurement, and maintenance planners should understand where the control valves should operate within the facility:

• Less than 10% open should be avoided since the valve will wear quickly.
• Plan to keep the range of control valve operation between 20% and 80% open.

If trending information on the valve is available, managers can quickly see if they are operating within the proper range. If not, they can provide the control valve manufacturer with new operational conditions and request suggestions on improving low flow performance.

The Solution

The takeaway is an oversized control valve will ultimately wear more quickly under lower than designed flow conditions. Plant managers can prevent erosion and limit maintenance spending by reviewing and possibly changing the control valve’s sizing. This can be done in one of two ways:

1. Replace the internal valve trim with the proper size for new operating conditions, or
2. Downsize to a smaller valve.

While a full control valve replacement is more expensive than a trim replacement, both solutions deliver significant long-term maintenance and operating savings.

DFT®’s HI-100® is a competitively priced severe service control valve with a low total cost of ownership. With robust features designed for long service life, the HI-100^® will help keep a plant’s maintenance budget in line.

Sign Up for Monthly Control Valves Tips

DFT® proudly offers a regular Control Valve Newsletters to address common industry applications. Applications covered in recent Newsletters include:

• Feedwater & Steam Drum Level Control
• Sky Vent for Combined Cycle Plants
• Turbine Bypass
• Soot Blower Control
• Attemperator Temperature Control

To receive monthly control valve Newsletters sign up for the DFT® Control Valve Newsletter.

Valve Basics Seminar Recap

Each year, the Valve Manufacturers Association of America (VMA) hosts a series of highly regarded Valve Basics Seminars & Exhibits to give industry associates — ranging from engineering students to experienced professionals looking to broaden their subject knowledge — a hands-on crash course in valves.

Last month’s three-day seminar hosted approximately 70 participants at the Embassy Suites Chicago O’Hare in Rosemont, IL. The dynamic program featured several speaker presentations highlighting different aspects of valves and valve safety, as well as the iconic Valve Petting Zoo, where attendees participated in hands-on demonstrations of what they’d learned earlier in the classroom.

Getting Hands-on with Valves

The Petting Zoo, a relatively new addition to Valves 101 developed based on past participant feedback, turned out to be the highlight of the program. On the second day of the seminar, after each speaker had an opportunity to present, they showcased their topics in action as attendees rotated around nine different stations to gain further understanding through hands-on learning.

“The valve petting zoo was outstanding,” said one attendee. “I learned a great deal by seeing how valves actually function and operate.”

Valves, Actuators & Controls 101 with DFT®

DFT®’s own Director of Sales and Marketing, Jeff Kane, and Regional Sales Manager, Bud Volz; have had the honor of presenting the Valve Basics Seminar & Exhibits for the past several years. This year, Kane’s course segment in “Valves, Actuators & Controls 101” focused on the subject of check valves, the importance of check valve sizing, and preventing water hammer.

In his presentation, Kane discussed how correctly sized check valves can minimize unnecessary costs by preventing low flow situations that lead to valve failure, as well as high velocity flows that can cause high-pressure shock waves (commonly known as water hammer. Students are given an unbiased presentation regarding the features and benefits of all the popular types of check valves.

Next Stop: Texas

Valves 101 will be stopping at the Sheraton Houston Brookhollow Hotel in Houston, Texas on October 18-20 for the next installment of the Valve Basics Seminar & Exhibits program. To date, over 1,500 people have attended these workshops; the VMA looks forward to expanding this number and continuing to spread the word on the importance of valves and valve safety.

To find out more about the next Valve Basics Seminar & Exhibits program and how to attend, visit the VMA.org website.

Learn more about check valves and how to avoid common sizing mistakes by downloading DFT’s free eBook, “Common Mistakes in Check Valve Sizing.”