Top Steam Trap Questions Answered by Experts -Part-2

Top Steam Trap Questions Answered by Experts -Part-2

Welcome to Part 2 of our expert-driven Steam Trap Q&A series. In this edition, we address some of the most frequently asked and practical questions related to steam trap selection, troubleshooting, monitoring, and maintenance.By reading this post, you will gain valuable insights into improving steam trap reliability, ensuring efficient condensate discharge, preventing steam loss, and optimizing system performance. This knowledge will help maintenance teams and operators extend equipment life, reduce energy waste, and enhance overall plant safety and efficiency.

Q. How do Thermostatic Steam Traps operate?

Ans: Thermostatic traps contain a temperature-sensitive element that contracts to open and

expands to close the trap, responding to the temperature difference between steam and

condensate.

Bimetallic Steam Traps: Use two different metals with different thermal expansion

coefficients that bend to open or close the trap outlet. They are suitable for high

temperature steam tracing applications.

 Balanced Pressure Thermostatic Steam Traps: Contain a liquid-filled capsule that

expands when heated, pushing a valve to its seat. They are ideal for steam tracing

applications and vent air and non-condensable gases.

 Liquid Expansion Steam Traps: Contain a liquid-filled capsule that expands when

heated, pushing a valve to its seat. They are adjustable and can evacuate subcooled

condensate and air.

Q. What is an Orifice Steam Trap?

Ans : Orifice traps use a very small orifice to discharge condensate continuously, designed to prevent steam loss. However, they are sensitive to dirt and debris, which can cause blockages or carryover. They are generally unsuitable for mainline applications due to potential plugging and high steam losses.

Q. How do I choose the right type of steam trap for a specific application?

Ans: The selection depends on various factors including pressure fluctuations, temperature ranges,condensate flow rates, and the presence of non-condensable gases. A comparison table for different trap types can guide selection. Key factors for process applications include equipment peak and minimum steam load, steam pressure, operating temperature, presence of temperature control, and back pressure.

Installation and Maintenance of Steam Traps:

Q. Where should mainline steam traps be installed?

Ans: Mainline steam traps should be installed at specific locations to ensure effective condensate removal:

• At every 30 meters along straight steam distribution lines.
•  At every change in elevation within the distribution network to prevent condensate accumulation at low points.
• At dead ends of steam lines, where condensate will accumulate.
• On headers, designed for separation of steam, air, and condensate.
• Before process equipment to ensure dry steam supply and improve heat transfer efficiency.
• Along with moisture separators to remove water droplets suspended in the steam.

Q. What are drain pockets and why are they necessary?

Ans: Correctly sized drain pockets should be provided to capture condensate formed in the lines so that it can reach the steam trap and be effectively evacuated. The inlet line to the trap should always be taken from the bottom of the drain pocket to ensure complete condensate removal.

Q.Why is a bypass valve important when installing a steam trap?

Ans: Steam traps should always be provided with a bypass valve and an upstream and downstream isolation valve. This allows for safe isolation, in-line maintenance, and inspection of the trap without disrupting the main steam flow. In cases of damage to the pipeline or accessories, manual opening of the bypass valve can prevent significant loss of steam.

Q .What is “group trapping” and why should it be avoided?

Ans: Group trapping involves using a single trap to cater to condensate evacuation from multiple pieces of equipment or more than one heating element of the same equipment. This practice is typically, prevalent across equipment like dryers or storage tanks. It’s a common problem that can lead to poor productivity, process temperature issues, high startup times, and increased