Steam trap testing, pt. 1

January 22nd, 2015

Steam traps are a common and integral component of virtually every industrial facility. As such, it is essential that plant managers understand how they function, why they exist and which methods are best suited for testing the traps. In his webinar, Steam Trap Testing, Tristian McCallion of Swagelok walked through these attributes and offered his insight on how to get the most out of steam traps and optimize a plant’s productivity.

In the first part of this segment, we will examine the reasons for a regular steam trap maintenance plan and outline a few of the best methods for steam leak detection.

The three main purposes of a steam trap are to remove condensate as soon as it forms, to prevent live steam loss and to remove air from the system. It accomplishes these purposes by venting gases, discharging condensate and – as the name implies – trapping steam. In this way, steam traps prevent plants from wasting energy and losing efficiency, dropping production rates and creating unnecessary safety hazards. As such, any plant maintenance system should make steam trap checks and repairs as a primary goal.

Steam trap tests save money and energy
In 1998, Fortune Magazine reported that DuPont saved $1 million a year at a New Jersey facility simply by testing and repairing defective steam traps. In 2015 terms, that million is closer to $1.5 million, which is enough to make a significant difference for any company. Additionally, a failed steam trap can create downtime, which can be extremely costly and also damage production rates.

Not only is the dollar figure substantial, carbon emissions can also be a serious issue when failed steam traps are left alone. On average, one steam trap leak can yield 43 tons of steam per year.

For these reasons, plant managers should implement a regular steam trap inspection survey. Regularly scheduled checks can accomplish a variety of goals:

  • Support a safer workplace: Steam leaks can be scalding hot, decrease visibility in the area and limit hearing. Steam leaks that occur outside the facility can freeze in the winter and become a tripping hazard.
  • Improve efficiency: Built-up condensate can slow start up and reduce process efficiency on heat exchange products. Similarly, condensate can make it difficult to know the temperature of the equipment affected. Removing that condensate safely will alleviate those symptoms.
  • Increase energy savings: Every dollar saved on fuel costs is the equivalent of $10 in sales, so the more efficiently a plant can use its fuel, the more profitable it will be.
  • Reduce trap failure: By proactively testing steam traps, plant managers can lower the instances of trap failure.
  • Solve unrecognized problems: Steam trap failure can be the cause of other equipment failures that might have seemed unrelated. The opposite is also true – problems in piping, layout, or other components can cause a steam trap to fail on a regular basis.
  • Prevent downtime: Unexpected downtime can be a serious detriment to production and income. By using predictive maintenance techniques, managers can avoid equipment failure and eliminate downtime.

Inspection methods

There are a number of tools that a plant manager can use to check steam traps, but all the best ones are part of a preventative maintenance plan – a method that addresses potential issues before they turn into equipment failure. Visual and temperature-based techniques are valuable supplemental tools, but the most reliable individual tool is the use of ultrasonic detection. Ideally, a good steam trap maintenance plan will use ultrasound along with visual and temperature inspections.

Ultrasonic leak detection is ideal because it is non-intrusive – it doesn’t require a steam trap to be opened, broken or otherwise tampered with in order to find out if the trap is functioning or not. Ultrasound will clearly indicate if steam is passing through the trap and the meter on an ultrasonic tool indicates the type of malfunction. If the trap is stuck open, there will be a constant sound. This issue can lead to massive steam loss. On the other hand, if the trap is stuck shut, there will be no sound whatsoever – meaning condensate flow is likely blocked off. When setting up an ultrasonic tool, typically frequency should be at 20 to 25 kHz. Lower pressure will require higher sensitivity, while higher pressure will call for lower sensitivity.

Infrared imaging is also a useful technique for leak detection. As ultrasound allows the user to hear something he or she would not normally be able to, infrared allows the user to see where steam is leaking and at what rate. There is a direct relationship between temperature and pressure, so infrared imaging can provide additional information about exact metrics of a steam leak. This information will help a maintenance team analyze what may be wrong with the steam trap and determine the best solution. Click here for Part 2.

Suggested Ultraprobe instruments for steam trap testing: Ultraprobe 3000; Ultraprobe 9000; Ultraprobe 10,000; Ultraprobe 15,000

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