Maintenance Technology August 2017 - 32

ULTRASOUND

It's Time to
Inspect Your
Steam Traps

Any steam system can leak, and any trap can potentially waste steam.
Properly performed, well-planned, routine system inspections are crucial.

SAVVY MAINTENANCE teams are consistent and
persistent in following a protocol that monitors plant steam
systems. According to a Steam Trap Inspection Guide from
UE Systems (uesystems.com, Elmsford, NY) these systems
should be inspected routinely-and for good reason: Faulty
steam traps not only waste energy, they can contribute to
pipe erosion, negatively affect product quality in various
processes, and even play a role in environmental pollution.
To be clear, the frequency of steam-trap inspections
is often determined by application. For example, steam
systems used just for facility comfort, i.e. heating, are usually
inspected annually (in the fall), while those associated with
production operations might be inspected biannually or
quarterly, depending on the impact of steam on the process.

Ultrasonic inspections
Ultrasonic testers translate the high-frequency emissions of a
trap down into the audible range where they are heard through
headphones and seen as intensity increments on a meter. Some
units have frequency tuning to filter out additional signals and to
tune into the sounds of steam and condensate while others have
on-board recording and data logging.
Although there are a variety of trap designs, for purposes of
inspection, there are basically two main types: continuous flow
and intermittent (on/off). Each type has its own unique pattern.
It's important to listen to a number of traps to determine a
"normal" operation in a particular situation before proceeding
with a survey. Generally, when checking a trap ultrasonically, a
continuous rushing sound will be the key indicator of live steam
passing through.
The most common method for ultrasonically testing a steam
trap is to touch it on the downstream side. The technician should
then adjust the sensitivity to the point where the trap sounds are
capable of being heard. This is usually a setting at which the meter's intensity indicator is in a mid-line position. Adjusting the
sensitivity to levels that are either too low or too high will make
the trap sounds difficult to hear. If frequency tuning is available
on the instrument, choose 25 kHz.
Important considerations
■ Since ultrasonic testing of steam traps is a positive test, it
provides results in real time. The main advantage of this
technique is that it isolates the tested area by eliminating
confusing background noises. Personnel, in turn, can quickly
adjust to recognizing differences among various traps.
■ While performing a steam-trap survey, it's important to
note specific trap conditions on a chart. Every trap should
have a tag with a corresponding identification code. Poorly
operating units should be documented in a non-compliance
report and follow-up procedures planned. Be sure to include
digital photographs of traps. These reports should reference
items such as trap number, condition, and date of repair.
■ As part of a quality-assurance procedure, all repaired traps
should be scheduled for re-test. A comprehensive report
describing the results of a steam-trap survey is recommended.
This report should include items such as the number of traps
tested, the number found in good condition, and the number
of faulty ones. A cost analysis indicating the gross amount
of savings, repair costs, and net savings associated with the
survey should also be included.
Keep in mind
Any steam system can leak, and any trap can potentially waste
steam. If performed properly, a routine, planned program of
steam-trap inspection and repair can continually pay for itself
and contribute to a company's bottom line in terms of productivity, quality, and energy savings. MT

-Jane Alexander, Managing Editor

For information and registration details regarding UE Systems' September 2017 webinar series on steam-system inspections,
email Adrian Messer at adrianm@uesystems.com, or telephone 914-282-3504.

32 |

MAINTENANCE TECHNOLOGY

AUGUST 2017

http://www.uesystems.com

Table of Contents for the Digital Edition of Maintenance Technology August 2017