Specialized in manufacturing compensators, expansion joints, baffle doors

What is a large size non-metallic compensator? Let's break the name into three pieces

Don't be fooled by the phrase "large-size non-metallic compensator". When disassembled, it is a straightforward industrial part: the compensator is the expansion joint, and its function is to absorb the displacement caused by thermal expansion and contraction of the pipeline; Non-metal means that the main body of the ring belt does not need metal bellows, but uses flexible materials such as fabric, rubber and fluoroplastics instead; Large size refers to a rectangle or circle with a large cross section-a side length of one or two meters or even larger, which is specially fitted to air ducts and flues. You go to our station "non-metallic expansion joint (fabric fiber expansion joint)" and "rectangular non-metallic expansion joint", which are typical representatives. To put it bluntly, it is a flexible connection that can be telescoped, specializing in serving large-diameter pipes.

Why can non-metals get bigger, but metals can't?

The metal expansion joint depends on the deformation of the bellows to absorb the displacement, but think about it, when the diameter exceeds one or two meters, how much does the wall thickness of the bellows have to be added? The difficulty and cost of processing are soaring up like a rocket, and the materials are easy to become unstable-yesterday, I heard from a friend in a steel mill that they tried a 3-meter diameter metal bellows, and it bulged within two months of installation. There is no such problem with non-metallic belts: silicone cloth, fluororubber and glass fiber cloth. These materials can be stacked into a large format of dozens of square meters, and it is no problem to do it on the spot. More importantly, it is corrosion resistance. The sulfur-containing flue gas in the desulfurization flue of power stations, the metal bellows will erode in a few months, and it is common for non-metals to last for three to five years. And guess what? Some foreign appliance plants use the non-metallic compensator in our station, and the ring belt is changed only once every ten years, which saves a lot of downtime losses.

There are three layers of structure: ring belt, frame and heat insulation. Don't think about complicated

The internals of large-sized non-metallic compensators are far less intimidating than the name. The ring belt is the core, and a layer of sealing film is sandwiched between the multi-layer fiber cloth, just like wearing a leakproof jacket for the pipeline; The frame is welded with metal angle steel or steel plate and is subjected to system pressure; The insulation layer is tucked between the loop belt and the frame to prevent the high temperature from spreading outside. Some working conditions require a guide tube to adjust the direction of airflow-the specific function of the guide tube of the expansion joint, as we talked about in the question and answer, is to reduce vortex erosion. The "rectangular non-metallic expansion joint" in our station is designed according to this logic. By the way, the national standard JB/T 12235-2015 specifically stipulates the strength and sealing requirements of these components. When you buy a product, if the other party doesn't even dare to mention the national standard, just pass.

The three most headache numbers in model selection: temperature, pressure and displacement

When making technical selection, customers like to ask these three parameters. Let's talk about the temperature first: the conventional silicone ring is fine to 250℃, and the fluororubber layer can carry it above 300℃, but don't exceed 400℃. After this thread, the fabric begins to carbonize, and the whole ring belt will be wasted. Stress? Large-size non-metallic compensators are generally used in low-pressure air duct systems, and the design pressure does not exceed 0.1MPa. If it is really high-pressure working condition, obediently choose metal expansion joints. What about the amount of displacement? Axial ± 100mm and horizontal ± 50mm are easy to do, depending on the number of circle layers and wrinkle design. Two days ago, a customer set the parameters of metal expansion joints. Tsk, it was completely confused-metal deforms elastically by bellows, and non-metal slides by fabric folds. The calculation formulas are different, and chaos will cause big problems.

Practical application scenarios are very concentrated: desulfurization in power plants, blast in steel plants, and cement kiln tail

You can see the shadow of large-size non-metallic compensators in any pipeline with large temperature fluctuation, strong medium corrosion and oversized cross section. Desulfurization flue of thermal power plant, blast furnace blast of iron and steel plant, kiln head and tail of cement plant, and waste gas pipeline of chemical plant-it is almost standard in these occasions. Moreover, it is often used in conjunction with baffle doors: for example, the "desulfurization flue gas baffle door" and "circular baffle door (double seal)" of our station are responsible for cutting off the airflow, and the compensator absorbs the thermal strain of the pipeline, which is indispensable. Rectangular air ducts must use rectangular non-metallic expansion joints, and circular air ducts can be rounded. Remember one sentence when installing: the ring belt cannot be twisted, the bolts must be symmetrically tightened, and the insulation layer should not be compacted-compaction will affect expansion and contraction.

Maintenance is simple enough to surprise you

Routine maintenance is to check whether there are aging cracks on the surface of the ring belt and whether the frame bolts are loose. Found a partial breakage? Treat it temporarily with special repair tape, but in severe cases, you have to change the tape as a whole. Don't worry about the money-a non-metallic compensator costs only 1/3 of the price of the same caliber metal, and it can be changed as fast as hell: loosen the bolts, pull out the old ring belt, stick in the new one, and tighten it again, and two or three people can do it in a day. You have to ask about longevity? Depending on the working conditions: the indoor clean air duct is 8-10 years, and the outdoor corroded smoke is 3-5 years, but compared with the 1-2 years of metal bellows, is it much stronger?

Let's first talk about how this "Type A" came from

In the circle of non-metallic compensators, Type A is not an official standard model-looking through JB/T 12235-2015 "National Standard for Non-metallic Expansion Joints", you can't find the word "Type A". It is a conventional name in the industry according to the structural form. To put it bluntly, it usually refers to the kind of structure with an integral frame, multi-layer composite skin, and flanged connection.

When you open the product page of "Non-metallic Expansion Joints (Fabric Fiber Expansion Joints)" on this site, you will find that the actual products match Type A-skin, thermal insulation cotton, stainless steel wire mesh and flange. Why is it called Type A? Because when the non-metallic compensator was first made, this simplest and most versatile structure was ranked first, and it became the default option over time. Like A4 paper for typing and typesetting, no one stipulates that it must be called A4, but everyone just calls it.

Dissecting a Sparrow: What Does a Type A Nonmetallic Compensator Really Look Like?

frame(angle steel or channel steel welding),skin(multi-layer composite of silicone cloth + fluorine adhesive cloth + glass fiber cloth),fill layer(aluminum silicate wool or rock wool). Here is a detail that is easy to overlook: the skin is not a layer of cloth, but stacked like a thousand-layer cake. Each layer of material is responsible for different functions-the outer layer is weather-resistant, the middle layer is pressure-bearing, and the inner layer is temperature-resistant. What is the temperature resistance you ask? The conventional A-type can carry about 350℃. If the flue gas temperature is higher, it has to be high-temperature resistant, such as the all-metal scheme of "high-temperature axial expansion joint" of this station.

Let's talk about the framework. A-frame is generally symmetrical on four sides, and can be made in circular or rectangular shapes. However, there is a pit when it is rectangular: the aspect ratio can't be too large, and the stress at the corners is concentrated when it exceeds 2:1, so the skin is easy to tear. We'll talk about this case later.

What is the difference between type A and type B and type C?

To be honest, the definitions of Type B and Type C of different manufacturers may be different. Some call the one with the guide tube type B, and some call the one with the insulation layer type C. But Type A is almost a consensus-the most basic, the cheapest, and the fastest delivery time.

Take a practical case. Two days ago, a cement factory purchaser called, saying that their pipeline went through the kiln tail flue gas, the temperature fluctuated greatly, and there was dust, so they had to have a non-metallic compensator. I asked him you choose type A? He's right. But when I looked at the working conditions, the pipeline section was square, and the aspect ratio exceeded 2:1. When the four-sided symmetric structure of Type A was used, the stress at the corners was concentrated, and the skin would tear before long. Finally, the "rectangular non-metallic expansion joint" is recommended, which is actually a variant of Type A, but the frame shape and corner treatment have been strengthened. So, don't stare at the letters. Whether the structure can adapt to the direction and displacement of your pipe is the key.

If the pipe is round and the temperature is not high, use Type A casually. However, if it is a square section, large displacement, and high temperature, you have to consider rectangular non-metallic expansion joints or metal solutions.

Which industries love to use non-metallic compensator type A?

For desulfurization flue in power industry, kiln head and tail in cement industry, and hot air duct in chemical industry, you can look through the product list of this site-"desulfurization flue gas baffle door" and "metal corrugated expansion joint in cement industry" are all matched. The biggest advantage of Type A is that it absorbs large displacements, especially lateral and angular displacements, which are unmatched by metal compensators.

For example, at the chimney outlet of a power plant, the thermal expansion is several centimeters. With a type A non-metallic compensator, one can handle the axial, transverse and torsional directions. If you are on metal, you have to string several models to achieve it. Moreover, non-metal has good vibration isolation effect and low noise, which is why power plants like it.

There were three pits in the selection and I've seen too many people fall into them

The first one: the temperature margin.The design temperature is 350℃, and you just choose Type A at 350℃. As a result, the flue gas contains sulfur and is corrosive, and the aging rate of the skin doubles. To leave a margin, at least above 50℃. The skin material under corrosive media should be upgraded, for example, fluorine tape should be used instead of silicone tape.

Second: Installation space.Type A generally needs to reserve an installation length of 200-300mm, and the space is not hard enough to plug, which compresses the compensation amount. Some customers only have a gap of 150mm on the site, so they have to install Type A. As a result, it collapses as soon as it is installed. In this case, it is better to replace a "rubber compensator" or a "rubber PTFE compensator", and it is better to use rubber for lateral displacement.

Third: media particles.With hard particles (such as fly ash) in the pipe, wear-resistant lining should be added to the inner layer of the skin, otherwise it will wear out in three months. The "rubber compensator" of this station can actually cover some working conditions, but its wear resistance is not as good as the A-type liner scheme. The cost increases by about 30% after adding liners, but the life can be doubled.

In this aspect of maintenance, Type A has an innate advantage

The skin can be replaced locally. Unlike a metal compensator, one breaks the whole cut. You open it every other year and check it to see if the skin is bulging and cracked, and if the insulation cotton has collapsed. Referring to the service life of the expansion joint mentioned in the question and answer of this site, generally, Type A can be used for 5 to 8 years under normal working conditions, but if the medium temperature fluctuates frequently or there is chemical erosion, it has to be replaced in three years.

When installing, apply a layer of high-temperature sealant to the flange connection, which can last for two years. In addition, if you find that the skin is partially damaged, you don't need to change the whole strip. Find a manufacturer to buy a skin piece of the same specification, and fix it by pressing the strip on the spot. Is it much less hassle than a metal compensator?

Let's be clear first: what is the "wet method" working condition, and why does it make ordinary expansion joints have a headache?

Wet desulfurization, at present, the mainstream is limestone-gypsum method. The flue gas from this process is pitifully low-usually 60-80℃, near saturated humidity, and full of a mixture of acidic droplets (sulfuric acid, sulfurous acid) and gypsum slurry. To put it bluntly, it is a harsh environment of "acid fog + mud".

This condition is a disaster for the metal expansion joint. Pitting corrosion, stress corrosion cracking, find your door in minutes. The stainless steel bellows you spend a lot of money on may leak in less than a year. Therefore, the industry generally turns to non-metallic expansion joints (fabric fibers, rubber) as the mainstream choice. But here's the question: Can any non-metallic expansion joint be installed?

Of course not. In wet working conditions, non-metallic expansion joints have to bear not only corrosion, but also dust accumulation, condensate water and frequent displacement fatigue. If you choose the wrong material, it will be powdered in half a year; The structural design is wrong, and it will get stuck in one year. Let's talk about it one by one.

The real advantage of non-metallic expansion joints in wet scenarios is not just "not afraid of corrosion"

Many people think that non-metallic expansion joints are powerful in anti-corrosion. In fact, what is more important is that they have strong ability to resist fatigue and absorb multi-directional displacement. For example, in our product lineNon-metallic expansion joint (fabric fiber expansion joint)Andrubber compensatorAnd can simultaneously cope with axial expansion and contraction and lateral deflection. The direction of the inlet and outlet pipeline of the desulfurization tower is complicated, and the thermal displacement is often not a simple straight line. It is difficult for the metal expansion joint to handle the displacement in multiple directions at the same time, but the non-metal fabric layer can easily absorb it. Moreover, the weight is light, the requirement for the bracket is low, and the installation cost is greatly saved.

But there is a big pit-if the material is not selected correctly, it will be wasted in half a year. You said you wanted to buy an ordinary silicone cloth cheaply and try to soak it in an acidic droplet at 60℃ for three months? Soak it straight away. Therefore, knowing the word "non-metal" is far from enough, and we have to dig deeper.

The first level of selection: How to pick the skin material? Don't just focus on "temperature resistance"

The temperature of wet flue gas is low, only 60~80℃, and general rubber can carry it. However, acidic dew point corrosion is an invisible killer-once the smoke condenses on the skin surface, forming dilute sulfuric acid, ordinary rubber immediately expands and cracks. Viton rubber (FKM), polytetrafluoroethylene (PTFE) liners are the base configuration. We have them in our stationRubber PTFE compensatorIt is specifically aimed at this working condition: the inner polytetrafluoroethylene film is acid-resistant and non-adhesive, and the acid drops up and slides away directly.

In addition, the outer layer should be protected from ultraviolet rays and mechanical damage. Some on-site pipes are laid out in the open air, and ultraviolet rays can brittle the rubber layer in a few months. The skin structure has at least four layers: corrosion resistant layer (contact with smoke), insulation layer (prevent condensation), reinforcement layer (pressure-bearing) and outer protective layer (prevent environmental aging). With one less layer, the lifespan is compromised.

In the structural design, the cooperation of rectangular non-metal expansion joint and circular baffle door is the key

Desulfurization flue is mostly rectangular large cross-section, in our productsRectangular non-metallic expansion jointThat's what it does. However, many problems on the spot are because the interface between the expansion joint and the baffle door is not handled properly. For example, you are matchedDesulfurization flue gas baffle doorOrDouble-sealed single-axis circular baffle doorThe compensation amount of the expansion joint is not reserved enough, and the compensation amount of the expansion joint is directly dead during high-temperature expansion. There are also deflectors-which must extend to the inward side of the media flow. Do you know why? If it is not extended in, the gypsum slurry in the flue gas rushes directly into the wave gap of the expansion joint, slowly hardens, and the ash accumulates thicker and thicker, and finally the ripples are stuck.

In addition, the drain outlet must be added. Wet pipeline condensate more, not draining liquid will corrode the frame. Some design drawings save trouble without opening a drainage hole, and the bottom of the expansion joint rust through after half a year's operation.

In installation and routine maintenance, 80% of faults are in the details

The tie rod nut is installed in the reverse direction. We wrote specifically beforeHow to adjust the tie rod nut of expansion jointThe locking surface of the nut must face the expansion joint body, otherwise it will be loosened after a few vibrations, losing the limiting effect, and the excessive amplitude displacement will directly tear the skin.

Shipped unreinforced and the skin was pressed out of permanent folds. In order to save freight, some manufacturers stack and transport the expansion joints. As a result, the skin has been creased at the site-this kind of gap is the easiest to hide acid, and it will quickly corrode and penetrate.

What is the key point of inspection under wet working conditions? Look at the surface of the skin for any maculae with acid oozing. That's a sign that the inner layer is leaking, and once it is found, it must be shut down for replacement. In addition, if the pipeline is out of operation for a long time (for example, the maintenance period exceeds two weeks), it is necessary to manually drain water regularly, otherwise the gypsum slurry will harden in the folds of the expansion joint, and the thermal stress will directly crack the hard block when driving. And guess what? I have seen a power plant that stopped the furnace for a month without draining water. On the day of resumption, the expansion joint burst, and the whole flue emitted white smoke.

Finally, let me say something that is easily overlooked: the national standard JB/T 12235-2015 has clear provisions on non-metallic expansion joints

The national standard JB/T 12235-2015 specifies the technical requirements, test methods and inspection rules of non-metallic expansion joints in detail. Such as flange width, bolt hole spacing tolerance, bond strength between skin layers. However, in order to reduce the price, some small factories narrow the flange by 5mm. During installation, the bolt holes don't match, and the workers forcibly pull the flange through the bolts-the result? The skin was ripped out of internal injuries, and the first inspection leaked air.

Made exactly according to national standardsRectangular non-metallic expansion jointThe import and export of the desulfurization tower of a power plant in Shandong has been running continuously for three years without changing; However, a low-priced product leaked in one year. After shutting down and changing it once, it burned 150,000 electricity bills, plus labor and material costs, which was enough to buy three qualified products. So budget is not an issue, the question is whether you can survive a major overhaul cycle-the downtime loss of replacing an expansion joint is enough to buy three qualified products. Listen to my advice, the national standard is not a decoration, but the bottom line of life-saving.

Rubber Compensator vs Non-Metallic Expansion Joint: What's the Difference? Don't wait until you put it on to regret it

Two days ago, an engineer doing a desulfurization project called and asked, "What is the difference between rubber expansion joints and non-metallic expansion joints? I think the quotation is similar, but the manufacturer said it is not the same thing." This problem is actually quite representative-many purchasing and designers are prone to confusing these two names, thinking that they are soft and can absorb displacement anyway, so just choose one. And the result? Either the rubber compensator (rubber expansion joint) is directly carbonized at high temperature, or the non-metallic expansion joint of the fabric fiber does not last a maintenance cycle in acidic medium. Today, I will break it up and crumble it into pieces to explain clearly how to choose.

Let's talk about the material and structure first-one like a tire inner tube, the other like an insulated quilt

The rubber compensator (rubber expansion joint) is made of rubber, usually nitrile, chloroprene or EPDM, reinforced with nylon cord or steel wire sandwiched inside, and equipped with a loop flange or fixed flange at the end. Look at its cross-section, it is a thick rubber layer and fabric skeleton, like the inner tube of a big tire. The non-metallic expansion joint (fabric fiber expansion joint) is completely different. It is made of multi-layers of flexible fabrics (glass fiber, ceramic fiber, PTFE coated cloth) superimposed, which can be filled with thermal insulation cotton in the middle and fixed with metal mesh or strip on the outside. Structurally, the non-metallic expansion joint is more like a stacked insulated quilt-it can withstand high temperatures but not pressure. Neither is the pure head-to-head compensation method of metal bellows, but the internal logic is very different.

Performance differences are the key — temperature, pressure, corrosion resistance, displacement, all of which make life or death decisions

Temperature is the first watershed. The upper temperature resistance limit of rubber compensator is usually 150℃, and the special formula can reach 200℃; Because of the use of ceramic fiber and high-temperature resistant coating, the working temperature of the non-metallic expansion joint can easily reach 600℃, or even over 1000℃ for a short time. You said that the flue gas temperature fluctuates between 180℃ and 350℃ in a desulfurization flue, using a rubber compensator? It carbonizes and cracks in less than three months. What about the stress? Just the other way around: the rubber compensator can carry 1.6MPa or even higher, while the non-metallic expansion joint is usually only used in the micro-positive or negative pressure pipeline of about 0.1MPa-you take the non-metallic expansion joint to connect the water pump outlet, and it will bulge and tear in minutes. Corrosion resistance is also a thing: rubber is afraid of strong acid, strong alkali and ozone aging, and non-metallic expansion extracted fluororubber coating is more stable in the harsh environment of desulfurization flue gas. In terms of displacement compensation ability, non-metallic expansion joints are more flexible in three-way displacement (axial, transverse and angular), and rubber compensators are mainly good at axial compression and a small amount of lateral offset. To put it bluntly, both have their own shortcomings, and choosing the wrong is gambling with the life of the equipment.

The application scenario is not a casual guess-if you choose the wrong one, the construction period and money will be lost

Flue duct of power plant, desulfurization system, flue gas pipe at the tail of cement kiln-these working conditions have low pressure but large temperature fluctuation, and the medium contains sulfur. Non-metallic expansion joints are all used in the industry. This site has rectangular non-metallic expansion joints, high-temperature axial expansion joints and other products to deal with this kind of scenario. Chemical, heating and water treatment pipelines, with high pressure, low temperature, and mostly water or weak acid and alkali, rubber compensator (this station has rubber PTFE compensator) is the most cost-effective choice. In extreme cases, such as the air-cooled island vacuum pipe, you have to use the double-hinged expansion joint or metal hose of the air-cooled island vacuum pipe. There are also those steam pipes that have both high temperature and high pressure-sorry, rubber and non-metal can't handle it, so you have to find universal corrugated expansion joints or external pressure single axial expansion joints. In the end, it's not just a question of which to choose, but you have to know what is running in your pipe first: How hot is it? How stressful? How corrosive is the media? Ask these three questions clearly, and the answer will come out by itself.

Finally, give a simple selection formula-remember these four sentences and step less than 80% of the pits

• Temperature over 250℃ or pressure below 0.05MPa, preference is given to non-metallic expansion joints (fabric fiber expansion joints).
• The pressure exceeds 0.5MPa and the temperature is below 150℃Rubber compensator is more reliable.
• The medium contains strong oxidizing agent or concentrated acidAsk the manufacturer one by one for a chemical corrosion resistance report, don't just look at the name of the material.
• If both high temperature and high pressure— Sorry, neither of these can handle it. We have to find the metal corrugated expansion joint.

There is no universal product, only the design that best suits the working conditions. After all, if an expansion joint is installed incorrectly, the loss of dismantling the pipeline and stopping production during maintenance can't be made up by saving that little selection time.

Do non-metallic compensators count as pipe fittings? Stop being stupid and confused

"Does your rectangular non-metallic expansion joint count as a pipe fitting? I checked according to the pipe fitting standards for a long time but couldn't find the model." This problem is actually quite typical-when many people select pipelines, they see that the nonmetallic compensator is installed in the middle of two sections of pipelines. As soon as the flange is twisted and the weld joint is dozen, it is automatically classified as "pipe fittings". But is that really the case? Let's be clear at the root.

Look at the definition first: Non-metallic compensator and pipe fittings are not the same thing at all

Non-metallic compensators, such as this site'sRectangular non-metallic expansion jointAndrubber compensator, mainly made of fabric fiber, rubber, PTFE and other non-metallic materials. Its core mission is to absorb the thermal displacement of pipelines, reduce vibration and noise-to put it bluntly, it is to serve as a "cushion" for pipeline systems. What about the pipe fittings? According to national standards, pipe fittings refer to rigid elements used to connect pipes, change direction or branch, such as elbows, tees, flanges, and reducers. Functionally, the pipe fitting is responsible for "hard connection" and the compensator is responsible for "soft compensation". Both are not on the same channel.

Then why do people still treat non-metallic compensators as pipe fittings? A common myth is the installation location: it is welded or flanged in the middle of the pipe and looks like a section of "special pipe part". However, the compensator itself does not have the function of pipeline circulation and load bearing, it is only a flexible compensation section. Think of it as in a plumbing systemjointWhile pipe fittings areSkeletal connector— Do you say joints can be considered bones?

Let the data speak: the ability of compensator, pipe fittings really can't learn

Let's take the products of this site as an example.Non-metallic expansion joints (fabric fiber expansion joints)The working temperature is often several hundred degrees, the corrosion resistance is strong, and the compensation amount is often tens or even hundreds of millimeters. However, ordinary pipe fittings (such as carbon steel elbows) are at most pressurized and guided. When encountering the stress caused by thermal expansion and contraction, it can only carry it hard-if it can't carry it, it will crack and leak. Another exampleFlue gas baffle doorThe matching non-metallic compensator specifically solves the stress concentration caused by thermal expansion of high-temperature flue gas pipeline. Can traditional pipe fittings solve this problem? Obviously not.

The compensator can absorb not only axial displacement, but also lateral and angular displacement. Like this site'sCompound hinge transverse expansion joint、Curved tube pressure balance expansion joint, are specially designed for complex displacement conditions. What about the pipe fittings? It can only provide fixed geometric connections with no displacement compensation capability. So functionally, non-metallic compensators are completely different from pipe fittings.

Standard system: each has its own "ID card"

"According to GB/T 12459 pipe fitting standard, is the non-metallic compensator missing?" In fact, nonmetallic compensators have their own exclusive standards- -JB/T 12235-2015。 This standard specifies the technical requirements, test methods and inspection rules of non-metallic expansion joints in detail. The pipe fitting standard does not cover it at all. Although it is classified as "pipe accessory" in some engineering classifications, "accessory" does not mean "pipe fitting". Pipe fittings focus on geometry and connection sealing, and compensators focus on displacement compensation performance-well water does not intrude on river water.

This site'sRubber PTFE compensatorAndPTFE compensatorIf you take the standard pipe fittings to set, the model does not match, and the parameters do not match. Why? Because the fatigue life, displacement absorption and temperature resistance grade are considered in the design of compensator, the pressure grade, wall thickness and sealing surface form are considered in the design of pipe fittings. Two sets of logic, when mixed together, will inevitably go wrong.

Conclusion: The non-metallic compensator is not a pipe fitting, so do not confuse the selection

Non-metallic compensators are not pipe fittings. It is a stand-alone element in the piping system specifically designed to compensate for displacement and dampen vibration. Next time someone asks you, just throw this sentence: "Pipe fittings are rigid connected, and compensator tubes are flexible compensated-different ways do not conspire." When selecting, do not remove the sleeve according to the parameters of pipe fittings, which is easy to cause problems. For example, if you choose the expansion joint with the pressure level of the elbow, you may ignore the displacement; Taking the temperature resistance of the tee to select a non-metallic compensator may not meet the working conditions at all. Don't believe it? Go check out this siteCorrugated expansion joint for power station industryAndMetal Corrugated Expansion Joints in Cement IndustryTheir parameter tables and fittings are completely different from the same way.

Find out the categories, and select models to reduce pits. A non-metallic compensator is a compensator. Don't stuff it in the pipe basket.