Cheltenham, UK – No matter how durable a steam trap may be, like any mechanical device, it will eventually need repairing and/or replacement. And the longer a trap is in service, the more opportunity it has to wear, which will lower the trap’s performance and can eventually impede operation.
Determining when a trap will fail is extremely difficult because a trap’s lifecycle can be influenced by a number of factors, including steam trap type, application, pressure, condensate load, piping configuration, and steam/condensate quality.
To help prevent premature trap failure and identify failures in a timely manner, every plant using steam should establish a steam trap management programme to help optimise the steam system and minimise costs.
Caption: The Basic Mechanism of Steam Traps
A properly operating steam trap will discharge condensate and incondensable gases while preventing unnecessary steam loss.
Unlike manual valves, steam traps regulate flow automatically and help prevent steam from leaking out of the system, while allowing condensate to flow through and be discharged.
Inspecting traps for failure does not only involve checking for condensate blockage or large steam leaks, but it is also important to check for smaller leaks and to confirm that the correct steam trap is installed properly. This includes checking trap type, pressure and temperature ratings, discharge capacity and whether the trap has been installed according to the manufacturer’s installation instructions.
Why Monitor Steam Trap Failure?
Steam trap failure occurs when a steam trap either leaks live steam or blocks condensate discharge.
Caption: Steam Trap Failure
Steam traps fail by either leaking out steam (left) or blocking condensate discharge either partially or completely (right).
Between the two types of failure, blockage can have the greatest impact on safety, reliability and production. When not discharged rapidly from a steam distribution system, condensate can back-up into steam headers resulting in wet steam and/or water hammer.
In process heating applications, a back-up of condensate can cause the heating temperature to drop. This in turn may increase defects and affect product quality. Blocked traps often have a direct impact on production, which often makes them easier to identify than leaking traps.
Conversely, leaking traps do not affect heating efficiency, but rather energy efficiency. Leaking traps result in significant amounts of wasted energy and money, but often remain unnoticed or forgotten because they do not directly affect product heating.
Caption: Wasted Energy = Wasted Money
Steam leakage can represent a significant waste of fuel, water, and treatment costs, and it can also greatly increase a plant's carbon footprint.
Testing Traps
To effectively check whether steam traps are operating properly or not, an inspection needs to be performed while the steam system is running and steam traps are in operation.
Since high pressure and high temperature steam is involved, the working parts of a trap cannot be inspected while a process is in operation. Surveyors therefore inspect other factors, such as:
- Trap appearance and orientation
- Trap discharge
- Temperature
- Pressure
- Vibrations (sound), etc.
From Steam Trap Management to Condensate Discharge Location Management
The true aim of a steam trap management programme is to ensure that steam processes run smoothly and efficiently in order to maintain high-quality processes and production and help conserve energy.
To achieve the best results, these programmes should cover more than just the steam trap. Surveyors should inspect the entire condensate discharge location (CDL), making sure to examine the drainage system around the trap, including all piping and valves associated with it. It is important to inspect the entire CDL to ensure that no problem areas are overlooked.
Recording and analysing data on the performance of steam traps and CDLs is also extremely important. For example, imagine that steam trap failure rate was lowered to 10% after establishing a steam trap management programme. Methods of lowering this rate further will vary depending on the specific characteristics of the failures, such as traps in the same locations failing repeatedly, or traps becoming more likely to fail after they reach a certain age. Only by analysing data to this level of detail can a plant develop an effective strategy for optimising their steam traps and CDLs.
To summarise, establishing a steam trap management programme is important in all plants using steam. It can help to conserve energy and maintain high efficiency throughout the steam system, but inspections should be regular and cover the entire condensate location to enable the maximum return possible.
For further information, call TLV Euro Engineering on +44 (0)1242 227223, email This email address is being protected from spambots. You need JavaScript enabled to view it. or visit www.tlv.co.uk.
