Steam Traps 101 Webinar – An Overview of Steam Trap Types & Technology

Steam Traps 101 Webinar – An Overview of Steam Trap Types & Technology

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hi everyone thank you for joining us for the latest installment of the tlv corporation webinar series i'm joined by my co-presenter alec newell my name is andrew mohr and we're going to be going through steam traps 101 today so basically covering different types of steam trap technologies along with sizing and selection considerations and just before we dive into things we'll go through this disclaimer quickly about the contents of this webinar so i'll give you a few seconds to read through that okay so i'll now turn it over to alec new who get things kicked off awesome thanks true so one of the key components to system optimization are your steam traps with proper sizing selection and installation steam traps can greatly enhance product quality as well as plant reliability so key a couple key goals to system or steam system optimization are to supply dry steam to your steam users as well as from that equipment and tracing drain that condensate quickly and efficiently and if possible return that condensate to help with overall system efficiency there are three main functions of a steam trap first to discharge condensate from the steam system after discharging condensate from the steam system that trap needs to be able to shut off tightly in order to prevent steam loss and last discharge any incandescent gases so there might be leftover air from your startup situation first trap type i'd like to cover is the thermostatic steam trap the operating principle for these traps are temperature so we're going to cover balance pressure capsules which is going to operate on temperature as well as pressure and then the bi-metallic trap it's going to operate solely on temperature so let's take a look at tlv's one of tov's balance pressure traps the main component here is our x element capsule i'll cover what that is so we have a valve head attached to two lower diaphragms and then two upper diaphragms that encase a thermal liquid this thermal liquid is a mixture of alcohol and water i'm sure many of you familiar with the saturation curve of water so as you increase pressure you also increase the boiling temperature of the water well by having a alcohol water mixture we can actually have a boiling point curve that's a certain degree lower than that water and so the goal here is to maintain a boiling point less than water at any given pressure this animation will take a look at what that looks like during operation so during startup your system is going to be full of air and cold condensate and that air and cold condensate as it begins to enter the steam trap it won't have the thermal energy to vaporize that thermal liquid so this point the trap is going to remain open and it's going to vent out any air and cold condensate the system starts to heat up we get closer to our steam which is going to vaporize that thermal liquid shutting the trap and this condensate that surrounding next element will need to sub cool for that trap to reopen and that's how this trap will begin to cycle so some advantages to this trap type it's very good at venting air during start-up conditions or if there's air in your system during operation it's very compact body and relative to its size it's got a high capacity because this trap operates on temperature it's not sensitive to any insulation orientation and tlv's x element is actually suitable for a small degree of superheat some considerations to think about when installing the steam trap is understand how it's going to operate it's going to back up a little bit of condensate before it reopens and so there's kind of a cyclical discharge to this trap as well as balance pressures pressure traps in general are not suitable for a high degree of superheat next i'm going to go over the bimetallic trap so this is a bi-metal strip it's made up of two different metals one being a high thermal expansion and the other having a low thermal extension so on this left side you'll see a cold unflexed element as it heats up that high thermal expansion side is going to actually curl over causing this element to bend so there's a few different valve types that i'd like to cover one being a upstream valve head so this the valve head is going to seat on the upstream side of the seating surface and on the other side you have your downstream valve head so this valve head is going to seat on the downstream seating surface of the seat so how does this look on the pressure temperature curve well since this is based on temperature we're going to have a fixed closing temperature with this upstream valve head design and the goal here is to set this temperature lower than our steam temperature at our given steam pressure there's a few more things to consider with a downstream valve head as the downstream valve head is going to have to work against the upstream pressure so that's actually going to give us a varying closing temperature so as you increase that inlet pressure that's going to cause the bi-metals to have to pull back even harder against that valve head in order for the trap to close again the idea here is still still to set that closing point lower than our steam temperature since those bi-metals are having to undergo a lot of strength just to pull back on that against the upstream pressure those bi-metals can start to become fatigued and they start losing some of their strength and so that requires a higher temperature under the same pressure so this can cause as you get a closing temperature that's equal or even higher than your steam temperature that will result result in a leaking steam trap last thing to consider with this downstream valve head design is back pressure is going to help those bi-metals close this trap and so as you increase back pressure it's actually going to be pushing up against that valve head closing that trap quicker than what it normally would ultimately resulting in a further degree of sub cooling in your condensate now going back to the upstream valve head design this is tlv's lex lex steam trap so you can see there's air and cold condensate entering this trap right now and those bi-metals remain unflexed this trap is wide open discharging condensate and as steam or hot condensate surround those bi-metals you'll see those bi-metals flex now that animation is sped up just to show how this trap cycles but that's pretty much how this trap will operate some advantages to this trap type you're setting that set you're you're able to adjust that set temperature to better match your application you can use this as a pre-freeze drainage so you set that temperature very low and that will open up to relieve any condensate in your life in your equipment before it freezes in addition this can be installed in any orientation since it's really operating off of the temperature change there's a built-in auger device for cleaning and i'll cover that in this next slide some considerations to think about when installing the steam trap know that it is going to back up condensate just like that balance pressure element and also you want to make sure you're setting that temperature to match your application so let's look at the augering device so this is kind of a built-in cleaning feature that tlv has incorporated with this steam trap model and so you can screw that adjustment screw all the way down kind of freeing any dirt and debris that may have settled on the seating surface this is very common in copper tracing if you're familiar with that the next trap i'd like to cover is mechanical steam traps the operating principle principle for mechanical steam traps is buoyancy so we're going to cover an inverted bucket trap a lever trap as well as tlb's free float so here's the animation of an inverted bucket trap you can see the buoyancy element is that bucket since it's upside down so this bucket's not going to have buoyancy until we build up a water prime and there's either steam or air inside of that bucket which is again then going to lift the bucket closing off your valve seat and you can see those linkages with your valve head and valve seat on the top side of that trap now when there's air in that bucket there's actually a tiny weep hole that slowly bleeds that air and that's how that trap gets rid of the air in the system just kind of during startup so as we get closer to our steam interface you'll begin to get steam introducing to this trap filling up that bucket giving that bucket buoyancy again which then closes off the trap and this trap will continue to cycle as that steam is either bled through the weep hole or condenses with the water prime that's in the bucket already so some advantages to this model depending on your material and connection size this can be a relatively inexpensive steam trap it's suitable for high back pressure so mechanical steam traps in general can handle a high back pressure as long as you maintain some sort of pressure differential and based on its operation this is suitable to be installed on a steam locking application some can some considerations to think about with this trap is its air venting capability so there's really just that there's no added element for air venting it's just that tiny weep hole and that will bleed air as well as steam without having a water prime this bucket has no way to float and so if you lose that water prime for some reason this trap will remain wide open one of those situations that you may lose your water prime is during super heat so this trap is not suitable for superheat as that superheat could vaporize your water prime inside of the sink trap it is a cyclical discharge that's just something you have to consider when using this trap and due to the linkages single valve head and single valve seat it's kind of susceptible to localized wear which will eventually lead to leakages as well as trap failure the next steam trap i want to cover is a lever float so this lever float actually has a thermostatic element inside of it and so during startup cold condensate and air that thermostatic element is going to be wide open and it's going to discharge air as condensate begins to enter the trap that floats going to become buoyant opening the lever mechanism allowing condensate to pass through the main valve seat and as our system heats up our xl or sorry not our x element the thermostatic element is going to close due to high temperatures and then once we discharge all that condensate that float and lever mechanism will then shut some advantages to the steam trap is it's more of a continuous discharge so because this is a float floating on the liquid level it will change based on what's coming in as i mentioned there is a thermostatic element so this is very good at venting air because of its lever mechanism it actually allows you to have incorporate a larger orifice size which then results in high capacities some considerations for the steam trap you still have similar linkages a single seating surface being a single valve head and a single valve seat which could eventually wear out giving you leaks and there's no added measure of protection against water hammer and so if you get into a water hammer event it could damage your lever mechanism or even damage your seating surfaces this trap is going to be sensitive to how it's installed based because of the float and lever mechanism the next the next trap i'm going to cover is tlv's free float so you'll notice there's a float in the bottom as well as the x element that i discussed earlier so we discussed how the x element operates it's going to be wide open during air and cold condensate so this will help out with the startup of your system as steam enters excellent is going to close and now our main operating function is that float and orifice at the lower side of the track as condensate begins to enter the trap the float becomes buoyant and just kind of modulates around that orifice allowing condensate to discharge downstream so let's take a look at what that looks like with an actual video so because this float has to become buoyant there it always is under normal operation a liquid level and the benefit to this is that orifice never really sees live steam and so there's really no way for livestream to leak through this orifice during normal operation some of the advantages to this trap type is there's a single moving part the only moving part in this trap is that free float and it's continuously rotating to give you a brand new seating surface continuous discharge and it's going to self-modulate based on how much content is coming in you saw in the animation when there's a lot of condensate coming in that float fully lifted off the orifice as well as the x element is very receptive to any air that enters into the steam trap it's going to open up and allow that air to vent during startup that x elements going to be wide open as well some of our free flip models do include a three point seating and so this is for your super heat conditions or your low load conditions where you may not have that water prime this three-point seating will ensure a very tight shut off with that float and the orifice additional advantage we've taken great care to make sure that this trap is has a high shock resistance to prevent any or to help mitigate any damage from water hammer some considerations to think about when installing this trap because there is the float it needs to seat against the orifice properly it is sensitive to installation orientation the last trap type i'm going to discuss is the thermodynamic or a disc trap so thermodynamic it operates based on bernoulli's principle so there's a relationship between velocity and pressure as velocity increases pressure is going to decrease as well so you can see here with a high velocity going underneath that sheet of paper it's going to create a low pressure pulling that sheet of paper down another situation if you had a high velocity going between two balloons it's going to pull those balloons together because of that low pressure now how does that work in a disc trap well a steam is pushing condensate through this trap condensate won't really have that high of a velocity and then as soon as steam reaches the bottom side of that disc that steam is going to wick across the bottom side of the disc creating a localized low pressure pulling the disc down into the seating surface once that disc is shut there's actually a small pocket of steam that gets trapped on the top side of the disc now with radiant heat loss that pocket of steam will slowly condense losing the closing force because that closing force is pushing down on the disc and our inlet pressure and our back pressure pushing up on the disc once that force dissipates the disc will then open again we'll take a look at what that looks like inside of the steam track so tlb has incorporated a thermostatic element to help with startup conditions or when there's air in the system so this thermostatic element is going to hold that disc off of the seating surface preventing it from fully closing so this is going to help with air and cold condensate during startup now once our system heats up and we start getting seam to this trap that steam again is going to create a localized low pressure under that underneath that disc pulling that disc closed then when our radiant heat we get radiant heat loss vaporizer condensing that pocket of steam on the top side of disc the disc will then cycle again some advantages for the steam trap this is very simple construction each model has a capability of operating underneath the wide pressure range it's very compact design and this track can be installed in any orientation being installed horizontally will give a longer life to the strap because all this uh this trap is made of solid pieces it's very it can handle up it can handle very high pressures as well certain models can some considerations to think about with this trap is it is a cyclical discharge that trap needs to open and close and so every time it's closed you're going to get a small amount of backup so you just need to consider that when installing this trap because your upstream pressures and downstream pressures are pushing up against your disc you need to be considerate of your down your back pressure because it is limited to between 50 and 80 percent of your inlet pressure most other models other than tlv disc traps don't have an added air vent capability there's no added thermostatic element and with this trap operating on radiant heat loss from that on the top side of the disc this is going to be susceptible to any wind or rain it's going to cause this trap to cycle more frequently let's take a closer look at what the thermostatic element looks like so there's a bi-metal ring that hugs the seating surface so when it's cold it's contracted holding that disc or preventing that disc from fully shutting why is that important well this disc trap doesn't really know a difference between air and steam and so air can create that same localized low pressure causing that disc to shut so you can see on the left that disc is shut and on the right side with the added air vent the disc never really fully seated and that air can pass freely if air is trapped on the top side of the disc without the thermostatic ring the only way for that air to discharge is by leaking through that steam trap so that's what i'm going to cover for the trap operating principles if you're interested in reading more tracy snow another one of our engineers wrote a fantastic article and that's available as one of the downloads to this webinar from there i'm going to pass it back to drew all right thank you alec let me grab control all right so now that we've gone through different steam trap technologies we'll take a look at different considerations whenever we're selecting uh and sizing a steam trap so if we look at our typical steam trap installation uh there's a few things we need to consider the first is what is the application we're draining and what is our condensate load next we're going to look at our operating and design pressures and temperatures are commonly known as pmo pma tmo and tma we'll also need to look at our size connection and material of our steam trap the last thing we'll need to consider is what is our back pressure or condensate recovery line pressure now when it comes to application requirements our applications are going to have very different requirements so things like steam distribution are going to have different requirements from let's say process heaters or from tracers so because the app the requirements are so different there's not a one type fits all steam trap for these applications so there's a lot of important considerations like is my steam superheated or saturated do i need continuous drainage or can i tolerate a cyclic discharge steam trap can i tolerate condensate backup and sub cooling or do i need to have immediate condensate drainage from that steam trap and these are just a few of them along with air venting so if we look at condensate load now condensate loads are usually either specified on a data sheet or we can measure or calculate these loads there's actually three different condensate loads that we need to take into consideration the first being our startup load which is typically the maximum load that we're going to see on an application that can be significantly higher than what we would typically see during normal operation of that steam trap because we have a large mass of pipe and equipment that needs to be heated on startup so that's going to require a significant amount of condensate to condense to get that up to temperature next is our normal load what we would expect to see during steady state or normal operation and with some steam traps we might also need to consider what is our minimum condensate load some steam traps may require a minimum flow rate in order to operate properly so these things can all uh affect what our steam trap sizing will look like another important factor for for condensate load is our sizing factor now our sizing factor is basically going to be a buffer uh between what our actual conditions are versus maybe some changes that we may see due to differential pressure or maybe a maximum startup load so typically we'll take our our calculated or specified condensate load multiply that by a sizing factor to establish our sizing load and this is going to vary based on the type of steam trap we have so typical sizing factors we see for something like a tlb free flow would be a 1.5 times sizing factor so for a steam application with a thousand pound condensate load we'd want to size that trap for at least 1500 pounds an hour and for other steam trap types we're typically going to see about a two to three time sizing factor applied but now an important note here is that this is going to vary greatly based on the manufacturer as well as your site specifications so we encourage you to look at your site specifications to determine if you have a specific sizing factor that you're required to meet or if your manufacturer recommends something much larger now looking at operating versus design conditions now our operating conditions we have our minimum normal and maximum operating conditions this is referring to our temperature and pressure and this is the conditions at which our steam trap needs to operate normally at within that range so if we look at pressure for instance we may be operating at a normal pressure but that application may have a range of a minimum maximum that that trap must meet now if we look at our design or our allowable conditions those are conditions that the trap needs to be able to physically withstand without damage but that trap may not be able to operate under those conditions so that's really just a safety type condition that you need to meet and that is going to usually be slightly or significantly higher than your normal or maximum operating conditions now the second important piece when sizing a steam trap beyond our condensate load is our differential pressure so if we look at a steam trap example a trap discharging from 145 psi into a return header running at about 29 psi our normal differential pressure is going to be our inlet pressure minus our outlet pressure or in this instance about 116 psi differential but that is not our maximum pressure differential if we were to take that same application and discharge it to atmosphere now our maximum pressure differential is actually 145 psi so we want to make sure that we're selecting a trap that will both discharge at our maximum pressure differential and yet still have enough capacity at what our normal or minimum pressure differential may be now there's some special considerations we need to take into account with pressure differential specifically with mechanical steam traps so mechanical steam traps unlike thermostatic or thermodynamic are very sensitive to differential pressure and we can install a very large orifice in our mechanical steam trap which will give us a very high capacity however there's a trade-off and we'll have a very low operating pressure with that large orifice now if we use a small orifice in our mechanical trap it'll give us a lower capacity but it'll allow us to use that same trap up to a higher operating pressure so we can see that there's a trade-off between orifice size and maximum pressure per operation now it's important to note that if we exceed that maximum pressure of that orifice our trap will not function and we'll actually lock it shut so if we need more capacity we're going to need to go to a larger trap rather than just going up to a larger orifice if we exceed the orifice pressure now we'll take a look at different types of connections for steam traps and this is pretty common throughout all types of valves and fittings the first is going to be a threaded connection so this is generally seen on low pressure applications and it's easy to install and fairly easy for replacement but the downside to that is it also is a potential leak joint versus something like a welded trap such as a socket welder butt weld trap which is typically used on medium to higher pressures but it is more difficult to install because it doesn't involve welding and it also is more difficult and takes longer to replace because it requires cutting and re-welding a steam trap in that line another common type of connection is your flanged connection these you generally see on larger steam traps and at higher pressures but replacement of this often requires either an exact face to face or piping modifications which can be a bit difficult another common steam trap connection type is what we call the quick trap connector this is a two-piece steam trap consisting of an inline connector and a steam trap module now with this it has a two bolt module which makes it easy for maintenance and replacement and it can be insta the connector can be installed in any piping configuration and since it is a bolt-on module there are different steam trap technologies that can be bolted onto the same connector so here's examples of tlv's free float along with a thermos thermodynamic as well as thermostatic trap modules that can be attached to that same connector and another nice thing is is that it is fairly universal across most steam trap manufacturers so many different manufacturers connectors will fit many different manufacturers steam trap modules now we can take a look at steam trap material and a very common material that we see is cast iron in cast iron this is generally seen for low to medium pressures and temperatures generally below about 450 degrees fahrenheit and this is very common in light industry as well as institutional type settings such as universities or district uh steam distribution systems another is carbon steel which is generally seen in higher pressures and temperatures typically up to about 800 degrees fahrenheit and it's good for higher for its higher strength and its corrosion resistance over cast iron and you see this very often in heavy industry such as the oil and petrochemical industry and then the third type of materials we see are stainless steel and alloy steels and these generally have the highest pressure and temperature capabilities uh sometimes up to a thousand degrees fahrenheit or more and it has very high corrosion resistance and we see this very often in the power generation industry because it is suitable for very high pressures and temperatures then we also see stainless in a lot of food and pharmaceutical applications because of its high corrosion resistance now it's important to also look at life cycle cost of a steam trap whenever we're taking all of these things into consideration so if we look at a few different different items for two different steam trap models we have model a which may have a higher initial purchasing price but it is a more energy efficient and a typically longer lasting steam trap versus model b which has a lower purchasing price but it's not as energy efficient or as long lasting so it's important that we look at the entire life cycle of that steam trap and what it looks like for failure and replacement because a longer lasting higher efficiency steam trap may cost us significantly less in the long run versus a lower price point steam trap and if you want to know more about uh steam trap and the costs associated with steam trap failures jim risco wrote a great article back in february 2011 uh published in chemical engineering progress magazine and this is attached to this webinar and you can also find it on our website so now we'll switch gears a little bit and get into steam using applications and look at typical equipment and applications for these steam traps and what do we need to really consider when selecting steam traps for these applications so we'll start off by talking about steam mains and steam distribution type applications we'll look at steam tracing as well as some process equipment and the different considerations we need to account for when selecting a steam trap so first we'll start off with steam mains and our drip pocket locations so this is a typical drip pocket with a condensate discharge location and we're generally going to want to see a drip pocket on a steam main about every 100 to 150 feet in order to drain out any condensate that is going to form due to radiant heat loss of our steam distribution piping and here we're going to want to have a full size pocket to allow condensate dirt to fall out of that steam system to be drained so we're not carrying it downstream degrading the quality of our steam and it's also ideal to locate those valves in that steam trap down low preferably near grade or somewhere where we have easy access so we can maintain that trap we definitely don't want it to have it up in the pipe rack where that steam trap is inaccessible and unmaintainable so here's an example of a condensate drip pocket sizing we want to make sure that we're that we have the appropriate diameter as well as depth of that pocket to allow that condensate and dirt to fall out of our system because if we make that pocket too small that condensate can basically pass right over it and we can carry that condensate down our system which can lead to erosion and potentially even water hammer now our condensate discharge location you can see here there's many different components and this is what we would consider an ideal condensate discharge location but the condensate discharge locations at your site may look a little bit different depending on what your site specifications are so you may see all or maybe only a portion of these components so first is going to be an upstream blow down valve followed by an inlet isolation valve next we have a y strainer which is helping protect that steam trap from dirt and debris and preventing that steam trap from being blocked which can cause condensate backup of course we have our steam trap as well as a bypass valve now for critical applications we might have a bypass to make sure that we have that we always have condensate drainage in the event that our steam trap becomes blocked or the steam trap requires maintenance so you may or may not see that bypass valve we have an outlet check valve if we're returning to a condensate return header that has a back pressure as well as an outlet isolation valve and a bloat and a downstream blow down or test valve which is going to allow us to see that condensate discharge to atmosphere for steam trapped troubleshooting now the steam trap requirements for a cdl on a steam main these are generally going to be very light loads and we'll get into load calculations here in a moment but we're going to want something that has little to no condensate backup as well as something that's going to have continuous discharge at or near saturation temperature and because on startup our system is full of air we're going to want to have a steam trap that is able to discharge that air out of the system quickly so for steam trap selections the best selections are going to be a mechanical style trap such as the tlb free float or a thermodynamic trap like our power dime alternatively you could use a balanced pressure thermostatic trap but we would definitely want to avoid using a bi-metallic trap because of its tendency to back up large volumes of condensate so now we can look at steam main startup loads now the startup loads are going to be significantly higher than our normal operating loads because we need to heat up the entire mass of pipe in our steam distribution system so we could look up this equation and find all of these variables looking at the specific heat of our pipe material the weight per linear foot and many other things similarly with our normal loads we can look at many of the same variables or we can do something much easier so tlv has published a condensate load calculator on our website for both startup situations as well as normal running load situations for your steam mates so if we go through an example of this looking at a typical steam main we'll say 100 psi steam header and 100 feet of six inch pipe with typical insulation in a very low ambient condition if we consider a one hour startup time our startup load for this type of application is only going to be about 101 pounds an hour so not a whole lot of condensate most half inch or three quarter inch seam traps are going to be able to handle that amount of load and if we look at our normal load it's even lower at only about 17 pounds an hour now if we have a very large diameter header of 24 or 36 inches and we have several hundred feet of pipe our steam loads our condensate loads could be significantly higher so we want to make sure that we take that in consideration because this will be very dependent on your length and your diameter your pipe now getting into some other types of distribution applications the first being our boiler header this is typically the first condensate discharge location downstream of our boiler the goal here is to supply dry steam from our boiler and we could potentially see high loads due to boiler carryover so this is going to be a much larger trap than our typical steam main drip trap so our trapping considerations here we're generally going to want to size this trap for about five to ten percent of our boiler capacity which is going to result in a large trap and we may even want redundant or multiple steam traps on this application to provide sufficient drainage and we're going to want something that is going to continually drain with minimal backup so our best selection here is going to be a large mechanical trap such as a free float control valve and pressure reduction stations are another important drain point in our condensate discharge location system so the application goals here are we want to drain condensate before and after the valve and that is to really protect that valve trim from erosion caused by condensate and we also want to prevent condensate from pooling when that control valve or pressure reduction valve is closed and a rapid opening of that valve with backed up condensate could lead to a water hammer incident so we want to avoid that so our steam trapping considerations here are going to be very similar to our steam main and work that we're going to want something with continual drainage so our best selections here are going to be a mechanical free float style trap or a thermodynamics trap and again we're definitely going to want to avoid that bi-metal risers and expansion loops we often see changes in elevation in steam systems either going over roads or around objects or just accounting for the thermal expansion of pipe so the application goals here are we want to avoid condensate from pooling which can lead to water cover of course condensate does not want to go uphill so it will not naturally go up these risers we need to drain it before and even after that riser and one thing we need to consider is bi-directional flow so in larger steam systems we may have multiple steam generation points so we could see flow in both directions along this pipeline depending on operation so we need to make sure that we have traps upstream and downstream of these expansion loops and again our trapping considerations are the same for a typical drip trap on a steam main another location is going to be the end of our steam headers our end of mains and here we're typically going to see a higher startup load as well as a high need for air venting especially on startup because everything is being pushed to the end of our system so for this we're typically going to want to have a higher capacity than a normal drip trap along with something that has good air venting or even adds supplemental air venting so our best selections for this will be a slightly higher capacity free flow trap or thermodynamic trap and again this is not the type of application we would want a bi-metallic steam trap on so next is steam traps on superheated steam mains now you may ask yourself well do i really need steam traps on my superheated steam main the answer here is yes you still need steam traps on superheated applications and the reason is you will still see a a pretty heavy startup load uh on initial system startup because that pipe is cold so you need to be able to handle that that condensate on startup now during normal operation you may see almost zero load but there are conditions where you may see uh condensate due to upset conditions where you lose superheat or there's a sudden surge of condensate or something changes in your system so you need to be able to adjust to those conditions so our trapping considerations here are that you need a trap that is going to provide a tight seal even under a no-load condition as well as something that's going to be responsive to any type of upset so here your best selection is going to be something like a three-point seated free float or one of our high pressure thermodynamic power dyne disc traps another location is a steam separator in our header now the goal of a steam separator is to remove and train condensate from your steam main and to supply dry steam throughout your plant so our goals here are that we need to remove a potentially high amount of condensate and typically we size that for at least five to ten percent of the overall steam flow rate through that pipe and we're going to want something with continual drainage so typically we're going to see a large free float style trap on a separator now often we see a large separator in line trying to be drained by a half inch small disc trap which often doesn't have nearly enough capacity in order to drain the amount of entrained moisture so it's important to really consider steam trap sizing with that separator so switching gears a little bit getting into steam tracing so steam tracing for those who may not be familiar we typically have a small diameter steam or copper tube that is attached to our steam system that is connected to the outside of a product pipe and the goal of this steam tracer is basically to provide just a slight amount of heat to that product pipe in order to maintain product viscosity so these are often used for winterization or freeze protection just to keep product pipe warm and our condensate loads are typically fairly minimal usually well less than 50 pounds an hour probably down into the 10 to 20 pound an hour range so our trapping considerations for a low temperature steam tracer one is it's going to be very light load so we don't need a very large steam trap we're going to want something that is very compact and easy to install because these are often just hanging on unsupported tubing rather than hard bite and often we see these in all different orientations so we want something that is not sensitive to its installation orientation we want to be able to select our desired amount of sub cooling because in some cases with steam tracing we actually want to use that sub cooling to heat that product and i won't be talking much about steam locking today but we will be talking about that two weeks during our steam traps 102 webinar but we often see steam locking applications with steam tracing so we want to make sure that if that is a case we need to mitigate that so our best selections for these types of applications are going to be small thermostatic or thermodynamic traps or even a bi-metallic trap depending on what our requirements are for heating that product now we also have high temperature steam tracing so the goal here is that we have a high need for thermal maintenance of that product this may be a very viscous product that we're trying to keep warm to make sure that everything flows properly so we want to make sure that we're getting as much heat into that product as possible with these tracing lines so we want to steam trap with no backup so our considerations here we want something with little to no sub cooling and again we're going to have very small loads usually less than 50 pounds an hour per tracing line so the best selection here would be a free float or a thermodynamic type trap another type of instrument another type of tracing is what we would consider instrumentation tracing so the goal here is to prevent that instrumentation from freezing so this is either a flow meter or analyzer or any other type of instrumentation that in cold climate may not operate properly if it gets too cool so we have a very low temperature requirement but if we have high heat provided to that instrumentation we may damage it so we want to be very careful not to provide too much heat to this application so our trapping considerations here generally they're low pressure very light loads and we're going to want something that is very compact and easy to install and here we're going to want to take advantage of a temperature adjustable trap to actually intentionally back up condensate and use the sensible heat of that condensate to do the heating rather than the latent heat of steam so this is a perfect application for something similar to our lex series temperature adjustable bi-metal trap all right moving on from tracing into our process type applications our hvac heaters and our air coils so often these are referred to as unit heaters comfort heaters many different names but basically they're doing some type of heating or personal comfort and the big goal here is that we want to prevent freeze damage of these coils so if we back up condensate in this type of coil we have very cold air in cold climates going across these coils it could freeze that condensate backed up in those coils and cause damage so trapping considerations we want something that has no condensate backup to prevent that freezing of those coils and the load on these are typically going to be a light to medium load maybe a few hundred pounds an hour but definitely more than our typical drip or tracer application we're going to want something with good air venting as well as something that's tolerant of dirt now one thing with these types of applications is they're often seasonally used meaning that they're turned off once it's springtime and they're never turned on again until the beginning of heating season and fall so that gives the system plenty of time to build build up dirt and scale and rust which will then be flushed into the steam traps on startup so we want to make sure that we can handle that best selection for this type of application is going to be a mechanical style trap such as a free float so calculating condensate loads for air heating applications we've actually made that very easy and we've included a calculator on our tlv website so you can enter in your application information for your air heating conditions and calculate your condensate load for that application right now we'll move into process heaters which can be very broad there's many different types of process heaters but we'll take a look at a common shell and tube type heat exchanger where we're taking cold product in the bottom in green we're heating it with steam on the other side of that heat exchanger and we're raising it up to a desired set temperature so the application goals here are to heat a product up to a desired temperature and we're going to want to vent air quickly out of this heat exchanger on startup especially if this is a batch operation type heat exchanger if we can vent air quicker we can have a a shorter batch time and one very important consideration and goal here is to avoid condensate backup because as we back up condensate we could be decreasing production as well as causing corrosion and even leading to water hammer within that heat exchanger now sizing a trap for a process here we can look at our heat transfer equation mcp multiplied by our delta t or we could look at our heat exchanger data sheet and that should give us the information we need for how much condensate is going to be produced out of this heat exchanger given our operating conditions but it's more it's more complicated than that there are many things that we cannot forget when sizing and selecting a steam trap for a process heater so we need to consider things like is my steam pressure changing with my product conditions and is my process temperature fluctuating at all or do i have seasonal changes in this heat exchanger running different loads in the winter versus different loads in the summer also need to consider if my condensate return my condensate return line pressure changes or if i temporarily discharge my condensate degrade so all of these things are going to greatly affect how we size and select a steam trap and most importantly we cannot avoid uh considering the st the heat exchanger going to what we call a stall condition now you might ask yourself what is stall i'm not going to go into detail on stall today but we've attached an article written by jim riscoe back in 2004 detailing what stall is why it happens and how that affects a heat exchanger and how that affects our selection of a drainage device for that heat exchanger you can also watch a recording of our refining and petrochemical applications problem webinar on our website now even though this is a refining and petrochemical webinar the problems are often seen throughout all of industry so it's not the stahl is not a unique application problem for refining but it's really universal so you can learn a lot about stahl in that webinar now when selecting a trap for a process heater what are the conditions that we need to take into account one we want to have a trap that is going to adjust to changes in our condensate load as well as our steam pressure we need something that has good air venting as well as something that's not going to back up condensate so our best selection here is going to be a mechanical trap such as a tlb free flow or if it's a large application a process float trap and if it is a stall application then we need to look at something more than just a steam trap but we need to look at something like a combination pump trap such as tlb's power trap now with all that to consider we don't want to have you burdened with sizing and selecting steam traps for process applications and getting that wrong so we want to be able to help you do that so tlv has what we call a condensate drainage application form we can send you this form you provide us with the operating conditions of your process heating equipment and we will provide you a recommendation with important notes about that application of how that steam trap or power trap should be installed and things that you need to consider when draining that equipment and this is something that we do as a service to you to make sure that you get that piece of equipment right and operating optimally we've covered a lot of different applications and a lot of different considerations so another thing that tlv provides is what we call a standard and trap application review so here we will work with you to provide the best model selection for your steam system based on your individual site specifications and you have you may have many unique steam applications some that we never talked about but we can look at those and come up with best best practice solutions for that as well as well as taking into account your preferred trap technologies from that we develop and we provide you with best practice installation diagrams based on your site's piping requirements and practices for all of these different types of applications this is basically to take the guesswork out of steam trap selection and sizing and make it simple and easy for you to to install those steam traps and optimize your steam system so we thank you for joining us today um our tlv consulting and entering services are available and in north america if you ever have a question about a steam application please feel free to reach out to us at 1 800 tlb trap or email us at ces tlb engineering dot com and if you're not in north america we do have 14 global offices so please feel free to reach out to a local tlv office close to you and they can provide that consulting and engineering services as well and as always please feel free to visit our tlv.com website where you can find the online calculator that i have shown here today as well as many technical articles uh beyond the three that we have shown today as well as watching this webinar recording and all other webinar recordings so with that we thank you for for joining us today and hope that you enjoyed our steam traps 101 please feel free to join us in two weeks for steam traps 102 where we will be talking about steam trap installation problems and frequent frequent problems that you see with failed steam traps so we thank you again and hope to join us in two weeks

2021-08-15 17:35

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