HOW DOES LDS TEST FOR LEAKS?

We use the LDS patented ValveAlyzer® System, site specific databases, custom test procedures, acoustic testing, complex thermal analysis, and other proprietary data analysis methods, to identify leaking Cycle Isolation Valves and Traps.

HOW MANY VALVES PER DAY ARE TESTED?

The average number of conclusions made per day is 50. There can be many more valves tested in order to make conclusions. This is because we identify the source of crosstalk.
Testing speed primarily depends on plant condition and support.
Nuclear testing typically takes twice as long as fossil.

HOW MANY PEOPLE DOES LDS SEND?

We normally send 2 LDS personnel. Occasionally we will send one for various reasons, such as job scope, availability, etc.

WHAT SUPPORT DOES THE PLANT HAVE TO PROVIDE?

• We will need your P&IDs (Flow Diagrams) and Heat Balance Diagram (Full Power) for the database and Loss Potential Analysis
• A contact person is required to answer questions about the diagrams
• Insulators may be required to install inspection holes.
• 1 and sometimes 2 Operators are needed to locate and stroke valves during testing.
• An Instrument Tech should be on call to adjust controls and actuators as needed.
• Prior to Post-Outage testing, LDS will need a list of fixed valves and related details.

WHEN SHOULD A SURVEY BE COMPLETED?

• Full Pre-Outage Survey should be completed to provide ample time for parts ordering etc. You will receive your final report within 10 days of on-site test completion.
• Fossil stations typically require 6-8 week lead time.
• Nuclear plants typically require 8-12 week lead time.

HOW OFTEN SHOULD A PRE-OUTAGE SURVEY BE COMPLETED?

Full Pre-Outage Survey should be completed prior to all scheduled long outage starts.
Audit surveys should be completed annually and at least 2 months before any scheduled short outage. This will maintain a current short list of valves to work in case of a short outage – planned or forced.

HOW OFTEN SHOULD A POST-OUTAGE SURVEY BE COMPLETED?

Post-Outage Surveys should be completed within two months or repairs and outage completion.

WHY COMPLETE POST-OUTAGE TESTING?

LDS encourages its clients to conduct post-outage testing to confirm repair success and to identify any potential new problems. A post-outage report identifies estimates of your plant’s cycle isolation loss improvement as a direct result of your efforts.

HOW MUCH DOES A SURVEY COST?

Typically, a survey costs 5 times less than a plant’s overall savings. Often times, more. We provide a significant return on investment with a very short payback period.
Our services are provided on a flat-fee, all-inclusive pricing method that includes both Pre and Post Outage testing. Pricing varies based on plant type and client status (first time vs. repeat).
Please contact a sales representative at 800.345.7157 to receive a formal quote.

WHAT WILL BE IN THE REPORT?

The report includes a list of leakers, in economic order for repair. Estimated fuel cost recovery is listed for each leaker.
There is also a list of tight valves that can be used to clear unnecessary work orders.
Where appropriate, LDS may also make specific repair recommendations.

HOW SOON CAN WE GET THE REPORT?

The Loss Potential Report and Database List are completed within 2-3 weeks after receipt of plant diagrams and purchase order.
The final written reports are delivered by PDF within 10 days of site departure.

ValveAlyzer® System Questions

HOW DOES THE VALVEALYZER SYSTEM WORK?

The patented ValveAlyzer® System records acoustic emission signatures in the range of 10 - 600 kHz.
Specialized hardware and software features separate leak signals from the high ambient background noise common to power plants. It determines:

• Does the valve leak?
• What is the likely extent of the damage?
• What is the rank of the leak in economic (fuel cost) terms?

DOES IT ONLY WORK ON STEAM VALVES?

It works on steam, water, and other liquids and gasses common to power plants. The original application was to find leaking valves in the circ water systems of submarines.

WHAT IS THE SMALLEST LEAK THAT CAN BE DETECTED?

The decay of turbulent eddies produces acoustic emission signals that are characteristic of a leak. The viscosities and flow velocities common to power plants ensure that almost all significant leaks are turbulent.

The existence of ambient background noise is the real limit of leak detection. The ValveAlyzer® System easily detects the existence of any background noise and readily removes it from the “actual” leak noise.

HOW IS IT BETTER OR DIFFERENT FROM AN INFRARED CAMERA?

An infrared camera does not provide insight regarding the extent of internal damage or the importance of the leak to heat rate.

Temperature methods do not adequately determine whether or not a valve leaks.
Higher temperature does not necessarily mean a leak. For instance, the expansion of steam from high pressure to a lower pressure is a refrigeration process. Sometimes the cooler valve is the one leaking. Some valves are supposed to be hot, even when tight.

HOW IS IT BETTER OR DIFFERENT FROM THE ULTRASONIC GUN WE ALREADY HAVE?

They pick up signals in a narrow band centered on 40 kHz. Power plants are full of strong ambient background noise within the 40 kHz centered frequency band. These ambient background noises give false indications of leakage.
Ultrasonic guns easily invisible gas leaks to atmosphere. Virtually all of LDS clients have and use this equipment for this purpose.