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Steam Trap Application and Maintenance

Wednesday, November 3, 2010

This session will cover the basics of what is steam and take you thru the various types of steam trapping technology as well as techniques for maintaining your steam traps and the cost savings involved in a properly maintained trap population, which ultimately will save you money.

  • What is steam?
  • Steam trap technologies
  • Causes for failure
  • Proper testing of steam traps
  • Cost savings

Good morning and welcome to the webinar. My name is Jennifer Addlestein and I am the marketing assistant for Industrial Controls. Today's webinar is steam trap application and maintenance presented by Jeff Nelson of Industrial Controls. The presentation will take about forty minutes and after the presentation we will take some time to answer your questions. During the presentation, feel free to enter your questions and to the chat interface on the right-hand side of your screen and they will be addressed at the end. We will also open it up to voice questions where you can raise your hand and you will be on muted so you can communicate directly with the speaker. Okay, at this time I will pass it over to Jeff to get us started.

Thank you, Jennifer. As Jennifer said, my name is Jeff Nelson and I just want to thank you for attending our webinar today. I want to go over our agenda right now and this will be what we will be discussing for the next forty minutes and hitting on each one of the subject matters. We are going to discuss, what is steam? We want to get a good understanding of that. What is a steam trap? Where are they used? What are the various types of traps that are used? What causes trap failures and the ultimate goal of this whole seminar or webinar is to discuss the cost and savings associated with your steam system.

What is steam? This is something we need to understand. Steam is a colorless vapor created when water is heated to boiling point. In the industrial world and the commercial world there are two types of steam. There is saturated steam. I know many people think that means a wet steam but it is not. Saturated steam is steam at a temperature of a boiling point which corresponds to its pressure. Saturated steam occurs when steam and water are in equilibrium. Superheated steam you will find more in the power industry. Superheated steam is steam heated to a temperature higher than the boiling point corresponding to its pressure. It cannot exist in contact with water nor contain water and resembles a perfect gas. This is a nice little page here to show you a saturated steam condition where we are discussing gage pressures. What you need to notice is as gage pressure increases, heat or temperature increases. As gage pressure decreases, you will see our latent heat or our BTU transfer increases.

What is a steam trap? Everybody hears the term. A steam trap is essentially an automatic condensate value that opens the flow of condensate, air and non-condensable gases and prevents the flow of steam. And all steam systems, we want to remove the water or condensate to prevent the loss of the BTU power of the steam we have.

Here is a good example of where our steam traps used. Steam traps are used in main steam headers, plant steam distribution lines, in your process lines for heat tracing; they are used at unit heaters for HVAC, at tanks for heating coils or jackets for your process, for process heat exchangers and for sterilizers for pharmaceutical. This is a relatively simple slide but what we are showing here is the basics of where a steam trap would be applied and how you would use it. You obviously have your boiler off on the left-hand side that will be distributing steam at a higher pressure. The reason you distribute the steam at a higher pressure is a very small specific volume thus you would use smaller pipelines. The steam would be at the high pressure taken throughout the plant. You will notice that we have a steam trap at the end of main generally at the low point of the main header. The steam then would be distributed to the different process areas. A good example would be on a low pressure system usually an air heater that would provide a process trap, a process heat exchanger, tracers, jacketed kettles and would then be returned back to your flush tank for reuse to make steam again.

What are the types of traps? There are several different styles. One style is a thermostatic steam trap. They operate in response to a surrounding steam temperature. In the thermostatic family, there are three different kinds. There is a liquid expansion trap, a bimetallic style, and a balance pressure thermostatic. In the mechanical steam trap family, mechanical steam traps rely on the difference in density between steam and condensate in order to operate. They can continuously pass large volumes of condensate and are suitable for a wide range of process applications. Basically there are two common types that you will find. One is a ball float and the other is an inverted bucket. Another family of traps is a thermodynamic steam trap. These have the unique operating principle which relies on the dynamics of water and flushed steam. They are simple, robust, very reliable and can operate up to very high temperatures and high pressure. There are two common types. There is the traditional thermodynamic or disc trap and the impulse style trap.

The slide here is indicating that this is our catalog that you can find both online and we can actually supply to you, we can have it mailed out to you. If you look under industrial valve section, you can find our offerings for steam traps. You would then follow down to basically page thirty. We have two different types of steam for offerings that we document in our catalog. We have Yarway and Watson McDaniel. What we are showing here is three pages that showed differing styles of traps that are offered out on the market. To your left, you will see basically a thermodynamic style steam trap. In the center, you will see a Yarway power trap basically, for the high pressure high temperature industry, the power industry. And to your right, you are looking at a repairable drip and tracer steam trap. These are all offered in our catalog on basically page 1105 and this would be an example of the type of information we will provide you with.

Trap selection. This is imperative that the proper trap be applied to the proper situation. If you notice to your left there, there are several types of steam traps, five different styles. In the center, we discuss operation and we discuss typical failure modes. They don't always fail in this matter but it is a typical or not normal failure mode. For a good example, you will be looking at a float and thermostatic trap. We talk about load we are talking about the amount of the condensate that the trap is sized to remove from your steam system. Basically a float and thermostatic would have no action on low load. On light load, it would have usually continuous and may cycle some. On a normal load, it will usually be continuous and may cycle. On heavy loads, it will be continuous and normal failure mode for a trap like that may be in a closed position because the valve is at the bottom. Notice there is inverted buckets, bimetallic and impulse. All of these traps have specific operating conditions and fits specifically in your system.

This is again another page out of our catalog. We are showing you a process thermodynamic steam trap produced by Yarway. In here we show you how to size and select. What you are seeing as we popped up on the right here is that every trap has a capacity that needs to be matched to its application. This is very important. As an example if you were to look at where the arrow is pointing to on the left-hand side, a steam trap of flow rate and pounds per hour. We are looking at 2000 pounds per hour. As you move across the trap model here, you are looking at let's say inlet steam pressure of 200 psi. If you follow the intersecting line between the 200 psi and the 2000 pounds per hour, the selection would be 1/2 inch 40D model steam trap produced by Yarway. This is on every one of our pages in our catalog and we also can assist you with the sizing and selection ourselves if you were to contact Industrial Controls.

This is a very good picture. This is a typical steam system that has been neglected. If you were to look in the upper left-hand corner, we are just depicting a steam trap system, a trap station that is having leaked by corrosion and many other problems obviously. On the right-hand side, we are showing a disconnected steam that is obviously in the fail open position. If you were to look very closely, it has obviously been tested. There is a tag hanging off of the values so just testing the valve or testing the trap is not the only thing that you should do. You need to replace and repair that to reap the benefits.

What kind of problems do we have with steam traps? In a system, 15 to 30% potential failed traps in systems that have not been maintained for three to five years. That means 5% per year average failure rate and the live steam escaping into the condensate system or drain line. Thousands of dollars wasted in energy due to failed traps and a major part of it is misapplied or poorly sized trap resulting in wasted energy or consistent trap failures.


Jeff Nelson

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