Steam Trap Testing and Troubleshooting
If you’ve ever worked with steam, you know it’s incredibly powerful. But did you know there’s a way to harness that power and use it for specific tasks? That’s where steam traps come in. This article will discuss how steam traps work, common problems that can occur, and how to troubleshoot them.
How Do Steam Traps Work?
A steam trap is a device used to remove condensate from a steam system. It allows steam to pass through while trapping the condensate on the other side. This is important because, if left unchecked, condensate can cause serious damage to your system.
There are two types of steam traps: mechanical and thermodynamic. Mechanical traps use a moving part to open and close, while thermodynamic traps use the difference in density between steam and condensate to do the same. The type of trap you need will depend on the application. Let’s take a closer look at how each type of trap works.
How Do Mechanical Steam Traps Work?
Mechanical steam traps have a movable element that opens and closes to allow or block steam flow. The most common type of mechanical trap is the float-and-thermostatic trap.
This trap uses a float that rises and falls with the condensate level in the system. As the float rises, it opens a valve that allows steam to escape. When the condensate level drops, the float falls and closes the valve, trapping the condensate on the other side.
Another type of mechanical trap is the inverted bucket trap. This trap uses an inverted bucket that sits inside a larger water chamber. When steam enters the chamber, it forces the bucket into an upright position, which closes a valve and traps the condensate on the other side.
As the steam cools and condenses, the bucket falls back into place, opening the valve and allowing any remaining condensate to be discharged.
How Do Thermodynamic Steam Traps Work?
Thermodynamic steam traps use the difference in density between steam and water to open and close a valve. When steam enters the chamber, it displaces the lighter water molecules, causing them to rise and close a valve at the top. This traps the condensed water on one side while allowing only steam to escape through an exit valve on the other side.
As more steam enters the chamber, it displaces enough water molecules to cause them to push open the discharge valve at the top of the chamber. This allows any remaining condensed water to be discharged before more steam can enter and raise the level again.
Once all the condensed water has been discharged, only steam can enter, and the trap will be ready to start the cycle over again.
Common Problems
Despite their simple design, steam traps can cause many problems if they’re not maintained properly. Here, we’ll discuss the most common issues with steam traps: liquid carryover and air binding.
Liquid Carryover
The most common problem discovered with steam trap monitors is liquid carryover. This happens when the trap fails to close, allowing condensation and water to enter the system along with the steam. This can cause corrosion and other damage to your system components.
There are a few ways to prevent liquid carryover.
- Install a Moisture Separator Upstream of the Steam Trap: One way to prevent liquid carryover is to install a moisture separator upstream of the steam trap. Moisture separators remove water droplets from the steam before entering the trap. This ensures that only dry steam enters the trap, which reduces the risk of clogging and corrosion.
- Install a Trap With a Higher Capacity Than Required: Another way to prevent liquid carryover is to install a trap with a higher capacity than required. When sizing a steam trap, it’s essential to consider the potential for liquid carryover. If you’re unsure how much liquid carryover to expect, it’s better to err on caution and install a bigger trap. A bigger trap can handle more liquid without clogging or corroding, prolonging its lifespan.
- Choose the Right Material for the Application: Finally, you can prevent liquid carryover by choosing the right material for the application. Some materials are more resistant to corrosion than others. For example, stainless steel is a good choice for applications with the potential for corrosion because it won’t rust as quickly as other materials. If you’re not sure which material is best for your application, be sure to consult with an expert.
Air Binding
Another common problem is air binding. This occurs when air gets trapped in the trap body or seat, preventing it from opening correctly. As a result, condensate can’t drain out of the system, leading to waterlogging and potential system failure.
There are a few things that you can do to prevent air binding from occurring in your steam trap.
- Install an Air Vent Downstream of the Trap: One way to prevent air binding is to install an air vent downstream of the trap. This will allow any air into the trap body to be vented out, so it doesn’t build up and cause problems.
- Periodically Bleed Off Trapped Air From the Trap Body: Another way to prevent air binding is to bleed off any trapped air from the trap body periodically. This can be done by opening the drain valve on the trap and letting some of the trapped air out. You should do this regularly, such as once a week, to ensure no build-up of trapped air in the trap.
Troubleshooting Tips
You can do three main things to troubleshoot a failing steam trap: check for leaks in the system, check the differential pressure across the trap, and listen for any strange noises coming from the trap. Let’s take a closer look at each of these steps.
Check for Leaks in the System
The first thing you’ll want to do is check for leaks in the system. A leaking steam trap can cause many problems, including reduced system efficiency and increased energy costs. Examine the steam trap area for any wet spots or drips to check for leaks. If you see any leaks, make sure to repair them right away.
Check the Differential Pressure Across the Trap
Another way to troubleshoot a failing steam trap is to check the differential pressure across the trap. This can be done by attaching a pressure gauge to the inlet and outlet of the steam trap. If there is a significant difference in pressure between the two sides, it’s likely that the steam trap is not working correctly and will need to be replaced.
Listen for Any Strange Noises Coming From the Trap
Finally, you’ll want to listen for any strange noises from the trap. A failed steam trap can sometimes make a hissing or whistling sound as it tries to release trapped condensate.
Conclusion
Steam traps are an essential part of any steam system – but they’re also one of the most frequent sources of problems. Here, we’ve discussed some of the most common issues and some troubleshooting tips that can help you identify and fix them quickly. Remember – if you suspect a problem with your steam trap, don’t hesitate to call a professional for help.
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