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How do you say non-metallic compensator in English? All three types of translation engineers use

Two days ago, a foreign trade buddy called me, and when he came up, he asked, "Hey, how do you say non-metallic compensator in English? I reported it to foreigners here, and they returned the email saying they didn't understand, which was embarrassing." This problem is actually very common, especially in the B2B circle. The Chinese product name you wrote was translated in the past, and foreigners didn't buy it at all. Today, we're gonna get this out of the way.

1. What is the use of understanding English terms? — — Foreign trade quotation, standard docking and technical documents can't be avoided

To be honest, there are only a few English words for non-metallic compensators, but if you use them incorrectly, big things will really happen.
Let's talk about foreign trade quotation first: the product name you quoted to the customer is "Non-metallic Compensator". the customer may think that you are talking about metal bellows, or directly ask "What's the material?". Because foreigners are used to calling them according to materials and structures, unlike us collectively referred to as "compensators".
Let's talk about standard docking: the official English name of non-metallic expansion joint is stipulated in the domestic JB/T 12235-2015 standard, but there is no such word in foreign standards such as EJMA and ASME. If you want to check the drawings with the European engineers, you have to use the terms they recognize, otherwise the other party will directly refund the order.
The technical document is the hardest hit area: "Fabric Expansion Joint" is written as "Non-metallic Bellows" in an installation manual, and foreigners have to think about it for a long time-does it mean cloth bags or the kind with metal mesh?
So, don't just look at one word. Behind it is the quotation success rate, technical communication efficiency, and the compliance of the whole project. If you get it right, you will save yourself a big deal.

2. The national standard has the final say: What is the official English name in JB/T 12235-2015?

Let's look at our own standards first. JB/T 12235-2015 "Non-Metallic Expansion Joint" clearly written: English name isNon-metallic expansion joint。 Note that "expansion joint" is used here instead of "compensator".
This standard tube is fabric fiber expansion joint (that is, the classification of "non-metallic expansion joint (fabric fiber expansion joint)" in our website). In structure, it is mainly rubber/fiber cloth + silicone cloth + thermal insulation cotton, which absorbs heat displacement by flexible materials.
So if the customer asks "Is there a national standard product?", you just throw this sentence : Non-metallic expansion joint per JB/T 12235-2015. Professional, nothing wrong with it.
But don't worry and be happy, the national standard is only for domestic use. If you send an inquiry to the United States, the other party will probably return to you "What's a non-metallic expansion joint? You mean fabric expansion joint?"

3. Expansion joint or Compensator? Can these two be mixed in English circles?

Don't mix. But you may not believe the reason.
In our Chinese context, "expansion joint" and "compensator" are exactly the same, as you can see in Article 14 of Q&A on this site. But in English, Expansion jointIs a common term in the industry, covering metals and non-metals; WhileCompensatorMore refers to "compensating devices", such as "pipe compensators" have a wider range, including Rotary compensators, sleeve compensators, and so on.
How do foreigners use it?
-People who engage in power generation, petrochemicals and HVAC, it is customary to say Expansion joint, especially equipment manufacturers.
-Boiler, flue, maybe Expansion joint for flue gas duct。
-For chemical pipelines, occasionally Compensator, but more common in European standards (such as DIN).
And guess what? I turned through hundreds of foreign inquiries. When 90% of foreigners look for non-metallic products, the key word is "Fabric expansion joint". So for the sake of insurance, write when quoting Non-metallic expansion joint/Fabric expansion jointDouble labeling is the most robust.

4. Don't just focus on one word: What products do Fabric, Non-metallic and Bellows correspond to?

There's a pit here that newbies are easiest to fall into.
Fabric expansion joint— — Fabric expansion joint, specifically refers to the compensator with fiber cloth/glass fiber/silicone cloth as the main body and without metal bellows. Typical products: "Non-metallic Expansion Joints (Fabric Fiber Expansion Joints)" and "Rectangular Non-metallic Expansion Joints" on our website. Flue gas, dust and low pressure scenarios are preferred.
Non-metallic expansion joint— — Non-metallic expansion joint, the range is slightly larger than that of fabric, and also includes rubber compensator and PTFE compensator. Like the "Rubber Compensator", "Rubber PTFE Compensator" and "PTFE Compensator" of this site are all of this kind.
Bellows— — Bellows, this basically refers to the expansion joint of metal bellows. However, some foreigners also call non-metallic ring structures "bellows", such as rubber bellows. However, most of the time, when you use bellows to report non-metallic products, the other party will mistakenly think that you want metal.
So to summarize:
-Fabric fiber type → Fabric expansion joint
-Rubber/PTFE type → Non-metallic expansion joint or Rubber expansion joint
Polytetrafluoroethylene type → PTFE expansion joint
-Don't use Bellows unless you are quoting metal Bellows (e.g. "Universal Corrugated Expansion Joints", "Corrugated Expansion Joints for Power Station Industry").

5. Practical suggestions: choose English names according to working conditions, and take stock of similar products of non-metallic compensators in this site

One thousand words, one thousand, one thousand, one thousand, one thousand, one thousand Let me give you a simple principle:
Look at the working conditions and set the keywords.
-Working conditions: flue gas, high temperature, rectangular pipe → in English Fabric expansion joint→ Corresponds to "rectangular non-metallic expansion joint" and "non-metallic expansion joint (fabric fiber expansion joint)" of this site.
-Working conditions: water, weak acid and alkali, flexible connection of pipeline → in English Rubber expansion jointOrNon-metallic expansion joint→ Corresponds to "rubber compensator" and "rubber PTFE compensator".
-Working conditions: strong corrosion, high temperature (PTFE) → English PTFE expansion jointOrTeflon expansion joint→ Corresponds to "PTFE Compensator".
As for other products, such as "metal hose", "PTFE-lined metal hose" and "flue gas baffle door", they are all metal systems or valve systems, so don't mix them into non-metal systems.
Finally, when you write an e-mail inquiry, include the title Non-metallic Fabric Expansion JointWrite the national standard number, size, medium, temperature and pressure clearly in the text. Foreigners can understand at a glance, and the quotation speed can be 50% faster.
Well, about "How do you say non-metallic compensator in English?" This matter, you shouldn't have to worry about it anymore, right? Next time you meet a customer and ask, just throw these words away, steady.

Find out what a "large-size" nonmetallic compensator is first

Many people ask "What are the large-size non-metallic compensators?" as soon as they come up, but they have to figure out the concept first. Large size, in the industry usually refers to pipe or air duct connections with a diameter or side length of more than 1 meter, or even to 5 meters or 10 meters. It is completely different from metal compensators-metal compensators absorb displacement by bellows, non-metal compensators use flexible bands, and the main body is made of fabric, rubber or PTFE composite. To put it bluntly, non-metallic is a layer of "soft connection", which can cope with multi-directional displacement at the same time, and is corrosion-resistant, high-temperature-resistant and light in weight.

And guess what? In places such as desulfurization flue of power plant and cement kiln tail, metal compensators can't bear corrosion and dust accumulation at all, while non-metallic compensators have become just needed. Therefore, don't stare at the selection of metal parts as soon as you come up, but first see if the working conditions are right.

By shape: What are the doorways of rectangle and circle?

Rectangular non-metallic expansion joint

Rectangular structure is mainly used in square flue and air duct. For example, the hot and cold air ducts of power station boilers and the inlet and outlet of desulfurization towers. OurRectangular non-metallic expansion jointThe frame is usually welded with angle steel or channel steel, and the loop belt is compounded with multi-layer fabric + insulating cotton + sealing film. This shape has the advantage of absorbing large lateral displacements and facilitating on-site installation. The disadvantage is that the pressure bearing capacity is weak, and it is generally only used in low pressure (≤0.1MPa) occasions. Two days ago, I met a cement factory customer. The size of the kiln tail flue was 3m ×4m, and the temperature was 350℃. Finally, I chose a rectangular non-metallic expansion joint, which took three years without any problems.

Circular non-metallic expansion joint

The circular structure is suitable for pipeline butting, with diameters ranging from several hundred millimeters to several meters. Unlike the metal bellows, the circular non-metallic compensator has no corrugated body, but is deformed by the wrinkles of the loop belt. It has the advantage of large axial compensation and is suitable for long straight pipes. Note that circular shapes also have to be connected with flanges or sleeves, so don't confuse them with metal hoses.

According to the material: fabric fiber, rubber, PTFE composite-how to choose different working conditions

• Fabric Fiber Expansion Joints (Non-Metallic Expansion Joints): The main material is glass fiber cloth, polyester fiber cloth, and then superimposed silicone rubber or fluororubber coating. The temperature resistance range is-40℃ to 450℃, and it can reach 600℃ in a short time. It is suitable for the high temperature and weak corrosion environment of power plant air duct and boiler flue. OurNon-metallic expansion joint (fabric fiber expansion joint)This is the type, the loop belt can be customized in layers and thickness.
• rubber compensator: The main body is synthetic rubber (e.g. butyl, chloroprene, EPDM). The temperature resistance is generally lower than 120℃, but it has excellent elasticity and can absorb vibration and noise. It is more used in pump inlet and outlet and air conditioning pipes. Note that rubber is afraid of oil and ozone, and lightning should be protected under working conditions.
• Rubber PTFE compensator: The rubber is lined with a layer of PTFE, which combines the elasticity of rubber with the corrosion resistance of PTFE. The upper temperature resistance limit is about 200℃, especially suitable for pipelines with strong acid and strong alkali media. This product is common in the chemical and pharmaceutical industries, such as ourRubber PTFE compensatorAndPTFE compensatorThe former is soft and the latter is rigid.

Select fabric fiber for high temperature and dust, select rubber for low temperature vibration, and select PTFE compound for strong corrosion. Don't be greedy and choose randomly, otherwise it will leak in three months.

Special scenario: desulfurization flue gas, cement kiln, power station air duct-what are the non-metallic compensators in these industries

Every industry has its own weird temper. Take desulfurization flue gas as an example. The temperature is not high (50-80℃), but the humidity is high and the acid-containing dew point corrosion is serious. At this time, anti-corrosion film (such as FEP or PFA) must be added to the fabric fiber band, otherwise it will rot for half a year. OurDesulfurization flue gas baffle doorIt is often used in conjunction with non-metallic compensators to form a sealed system.

In the flue of cement kiln, the temperature fluctuates greatly, from 200 ℃ to 500 ℃ instantaneously. The non-metallic compensator must choose high-temperature resistant ceramic fiber cloth, and increase the thickness of heat insulation layer. I have seen some manufacturers use ordinary glass fiber, and as a result, it hardens and cracks in a month.

The air duct of the power station is oversized (5 meters ×5 meters at every turn), and it needs to absorb axial, lateral and angular displacements. At this time, rectangular non-metallic expansion joint is the first choice, and the ring belt should be pre-compressed and installed, otherwise it is easy to tear during thermal expansion. Our product information also includesCorrugated expansion joint for power station industryBut that is for metals, and the selection logic of non-metals is completely different.

Selection and pit avoidance guide: size, compensation amount, temperature, pressure, one parameter is wrong, it is useless

• Dimensions: Measure the spacing between the outer wall of the pipe, do not press the inner diameter. To calculate the peripheral length of the rectangular piece, the width of the ring belt must be greater than the design displacement, otherwise it will be broken.
• Compensation amount: Axial, lateral and angular displacements should be listed separately. The compensation ability of non-metals is greater than that of metals, but it depends on the number of belt layers. In general, a single layer of fabric can compensate for ± 50 mm, and a multi-layer can compensate for ± 150 mm. Don't just look at the maximum value of the sample, but actually leave a margin.
• Temperature: Continuous operating temperature and instantaneous peak temperature are two concepts. When selecting the material of the ring belt, the peak value must not exceed the material limit. For example, silicone rubber coating is ≤250℃, and fluororubber is ≤280℃. If it exceeds, polytetrafluoroethylene or all fabric must be used.
• pressure: The withstand voltage of non-metallic compensators usually does not exceed 0.1MPa (about 1kg), but some reinforced types can reach 0.25MPa. Above this value, don't consider non-metals, and honestly go to metal expansion joints.

A steel mill chose a rubber compensator for use on a 300℃ flue gas pipeline, but it burst in two weeks-because rubber couldn't withstand the high temperature at all. Therefore, the parameters are not accurate, and no matter how cheap it is, it is a waste.

Installation and maintenance: Why are non-metallic compensators more delicate than metallic ones?

Non-metallic compensators are delicate because the bands are flexible and susceptible to mechanical damage. There are a few points to note when installing:

• The loop belt cannot touch sharp objects and is best protected when transported.
• Check that the loop strap is in good condition for scratches or air bubbles before installation. Don't wait until the bolts are finished to find an air leak.
• The flange connection should be symmetrically screwed, and the torque should not be too large, otherwise the ring belt will be crushed. Generally, it is sufficient to screw M16 bolts to 50N·m.
• After installation, adjust the tie rod or limit bolt to ensure that the initial pre-compression amount meets the design requirements. You can refer to our question and answer "How to adjust the expansion joint tie rod nut", which has the same principle.

In terms of maintenance, regularly check the surface of the ring belt for aging cracks, and measure the wall thickness every six months. Don't wait for a leak before replacing it. At that time, the flue is full of smoke, and it is difficult to repair it. Many factories will prepare a set of ring belts as wear parts and replace them at any time. Compared with the metal compensator, which needs to be replaced as a whole, the non-metal ring belt can be replaced separately, which is a money-saving advantage.

So, don't think it's delicate, use it in the right place, and it can save you a lot of downtime costs. The key is to select the type accurately and install it fine.

What job does silicone cloth carry in a non-metallic compensator?

Let's be honest first-many users ask "How to use silicone cloth for non-metallic compensator?" As soon as they come up, thinking that this thing is like plastering, just tear it open and stick it on. Tsk, it's so simple, the equipment factory has long gone out of business.

Silicone cloth is the core skin material of non-metallic compensators (also called fabric fiber expansion joints). It does three things:Temperature resistance, sealing, displacement absorption。 For example, in the smoke duct of power plant and the hot air duct of cement plant, the medium temperature always soars above 300℃, ordinary rubber can't bear it, and the metal is too hard to absorb large displacement. At this time, silicone cloth comes in handy-the silicone rubber coated on its surface can bear high-temperature oxidation, and the glass fiber base cloth provides strength. After the combination of the two, it can deform softly without being burned through.

But don't think it's all-purpose. Two days ago, I met a customer who used a silicone cloth skin in a flue gas pipe containing concentrated sulfuric acid. As a result, it rotted in three months. Why? Silicone cloth is acid resistant but not strong acids, especially organic solvents. If the corrosiveness of the medium is not clear, it will be useless to change any material.

When choosing silicone cloth skin, don't just look at the thickness: temperature, pressure and medium corrosiveness are the key parameters

Many purchasers ask "How thick is it?" as soon as they pick up the silicone cloth. Every time I want to ask back: Where are you buying a quilt? Thickness is of course important, but what is more critical are the following three parameters. One less is easy to step on pits.

• Temperature: The temperature resistance range of silicone cloth is generally-60℃ ~ +250℃, and the special formula can reach 300℃ for a short time. If the medium temperature exceeds 250℃, composite polytetrafluoroethylene (PTFE) membranes or other high-temperature resistant layers should be considered. Don't believe the nonsense of "almost working". If the temperature exceeds the standard of 100℃, the life may be shortened by 80%.
• pressure: The non-metallic compensator itself is not resistant to high pressure, and is usually used in smoke and air systems with positive pressure ≤0.1MPa. If the pressure exceeds 0.15MPa, it can't be supported by silicone cloth skin alone, so it is necessary to add stainless steel wire mesh reinforcement layer or use metal compensator instead. For specific parameters, refer to this site'sNon-metallic expansion joint (fabric fiber expansion joint)Product page, where detailed pressure-temperature curves are available.
• Medium corrosivity: This is the easiest place to roll over. Silicone cloth has good resistance to weak acid, alkali and salt spray, but when it encounters strong oxidizing acid (such as concentrated nitric acid) and halogen gas (such as chlorine), it will bubble and crack in minutes. At this time, either change the fluorine rubber coating or please come outPTFE compensatorTo the rescue.

Also, don't forget to watchNational Standard for Non-Metallic Expansion Joints JB/T 12235-2015, which clearly stipulates the peel strength, aging performance and other test methods of skin materials. When purchasing, don't just look at the thickness. If you want to open your mouth, ask the supplier for the temperature resistance grade and media compatibility experiment report-this is what veterans should do.

The 3 most overlooked details before installation: storage environment, flange surface treatment, and tie rod pre-adjustment

After the silicone skin arrives, don't rush to the pipeline. These three details are not done properly, and it is also a ticking time bomb when loaded.

First, the storage environment.Silicone cloth is afraid of ultraviolet rays, ozone and humidity. If you leave it in the open yard for a month, and the surface is cracked and then loaded, can it still be called compensation? It should be placed indoors in a cool and dry place at a temperature not exceeding 40℃, away from heat sources and chemicals. It is best to check the production date when entering the factory, and don't use old materials that have been in stock for two years.

Second, flange surface treatment.The non-metallic compensator is sealed by clamping the skin with a flange. If there are welding nodules, burrs and unevenness on the flange surface, it is the air leakage point when pressed. Before construction, it must be polished and smoothed, and the oil and iron debris must be cleaned up. The most outrageous case I have ever seen-the old sealing strip left over from the last overhaul is still stuck on the flange surface, and the new skin bulges when pressed onto it.

Third, tie rod pre-adjustment.Non-metallic compensators generally come with a tie rod (also called a limit device), and the tie rod nut is pre-tightened to the installation length when it leaves the factory. Before installation, make sure that the tie rod is not loose or deformed due to transportation. How exactly to adjust? Refer to the FAQ on our siteHow to adjust the tie rod nut of expansion joint》: First loosen the locking nut, let the tie rod be in a free state, wait for the compensator to be aligned, then re-adjust to the designed length, and finally tighten the lock nut. Don't be too troublesome, this step is saved, and the later compensator may directly break the pipeline.

Installation of non-metallic compensator silicone cloth: From hoisting alignment to bolt tightening torque

OK, now to the chase-how to use non-metallic compensator silicone cloth? Do it hand-by-hand.

Hoisting alignment:Use a sling or soft rope, and it is strictly prohibited to strangle the wire rope directly on the skin. Let the compensator and the pipe flange naturally connect first, and do not force it with bolts. If the misalignment exceeds 2mm, adjust the pipe support instead of hard pulling the compensator. Ensure that the compensator is in a free state (without twisting, deflection) when aligning, otherwise additional stress will occur during operation.

Bolt tightening:This is the most problematic link. Many people used wind cannons to snap tightly when they came up. As a result, the skin was squeezed into deformation and the seal failed. Correct practice: Tighten symmetrically in 3-4 times, and the final torque is according to the design value (usually 40-60N·m, depending on the bolt specification and skin thickness). The tightening sequence refers to the cross diagonal method of flange bolts, first inside and then outside. Remember one principle:Compress but not kill。 The silicone cloth skin requires a certain amount of compression to seal, but excessive compression can reduce the fatigue life.

Tie Rod Adjustment:After the bolts are screwed, check that the tie rod still maintains the factory pre-adjusted length. If the pull rod is unevenly stressed due to pipe displacement, it is necessary to re-adjust the nut position to ensure the normal limiting function. This step can be referred toCorrect installation method of expansion joint of large tie rodKey points in: Keep a 2-3mm gap between the tie rod nut and the ear plate to avoid rigid constraints.

Pressure test and inspection:After the installation is completed, carry out an air tightness test (≤1.25 times the design pressure), focusing on checking whether there is air bubble leakage at the flange joint. If there is no condition to do the air pressure test, you can also do a light inspection-illuminate one side of the compensator with a flashlight, and observe whether or not light is transmitted on the other side. Once light leakage is discovered, stop the machine immediately to re-tighten or adjust the gasket.

Installation is not the end point: aging cycle, leak troubleshooting, and replacement timing of silicone cloth

It's all right when you install it? Wrong. The lifetime of a non-metallic compensator is largely dependent on post-curing.

Aging Cycle:The theoretical life of silica gel cloth is 3~5 years under normal working conditions (temperature ≤200℃, no strong corrosive medium), but it is greatly influenced by environmental factors. For example, in the back section of the desulfurization flue gas baffle door, the humidity is high, the acidic condensate is large, and the life may only be 1~2 years. It is recommended to check the skin surface every 6 months to see if there are blisters, cracks, stiffness or exposed fibers. Once these signals appear, it means that the silicone cloth has entered the end of its life.

Leak Troubleshooting:In daily operation, if there is an abnormal temperature rise around the compensator (more than 10℃ higher than the surface of the pipe) or a hissing sound is heard, the seal failure can be basically judged. At this time, don't rush to change the whole skin. First, check whether the flange bolts are loose and whether the tie rod is stuck. A lot of times tightening the bolts will solve it. If the skin itself is broken, consider replacing it-but be aware that changing only a single skin may cause secondary leakage due to the different expansion coefficients of old and new materials. It is best to replace the whole compensator together.

Replacement timing:Don't wait until it leaks into a jet plane. When any of the following conditions occur on the skin surface, it is recommended to stop the machine immediately for replacement: ① The exposure of the fabric layer exceeds 5% of the total area; ② The peeling depth of the coating exceeds 1 mm; ③ Penetrating holes or cracks appear. Remember to release pressure and vent before replacing. After removing the old skin, check whether there is rust on the flange surface. If necessary, remove rust and paint. Check the batch number before installing the new skin and avoid mixing different batches of products (due to different degrees of vulcanization).

How to use non-metallic compensator silicone cloth? In fact, there are three core points-choosing the right materials, installing the right process and maintaining the right time. Understand these three points thoroughly, and your plumbing system will have at least 80% less leakage problems. Don't believe it? Try it.

Standard life is just a reference value

JB/T 12235-2015 stipulates that the design life of non-metallic expansion joints is usually 10-15 years, but there are many projects that can last for three to five years in actual projects. The life span of this thing is never determined by the manufacturer. The key depends on how you use it. Take the desulfurization flue of power plant as an example. With corrosive gas and high temperature, non-metallic expansion joints (fabric fiber expansion joints) can last for three years, even if they are high-quality products. On the other hand, it is not unusual to use it for more than ten years in clean ventilation ducts. You ask about the lifespan of non-metallic compensators? The standard is the standard, the reality is the reality, don't take the national standard as a life-saving talisman.

Material determines the upper limit, working condition determines the lower limit

Rubber compensator, rubber PTFE compensator, fabric fiber expansion joint-different names, different lives. Rubber is afraid of aging, PTFE is afraid of high temperature, and fabric fiber is wear-resistant but afraid of acid and alkali. Two days ago, I met a customer from a cement factory, who chose the metal corrugated expansion joint in the cement industry. It was not said that the non-metal was cheap and had to be replaced. As a result, the high-temperature dust was washed and it leaked in three months. It's not that non-metals can't be used, you have to find out its temper: when the temperature exceeds 200℃, it begins to lose its life, and the particulate matter in the medium is a life reminder. Alas, in the final analysis, the material just gives you a theoretical ceiling, and the working condition is the real floor.

Installation and maintenance is the real watershed

Whether you put it right or not, the difference is three to five times the life span. There are three common pits: First, the guide tube is installed backwards, and the airflow directly washes the compensation layer; Second, the tie rod nut is adjusted too tightly, which limits the displacement compensation and forcibly cracks the material; Third, there is no pre-deformation left during installation, cold deadlift, and it will explode as soon as it is turned on. You asked how to adjust the expansion joint tie rod? The manufacturer's manual is clearly written, but the on-site master can save trouble and screw it to death directly. No matter how good a non-metallic compensator is, it can't handle this. Is that the truth? If the installation and maintenance are not in place, no matter how good the material is, it will be in vain.

When should I change? Don't wait for it to be completely scrapped

Leaks, surface hardening, fabric delamination, noticeable distortion-don't hesitate to show any of them. Especially the non-metallic expansion joints near the desulfurization flue gas baffle doors corrode faster than you think. It is recommended to check at least once a year, focusing on flange joints and fabric overlap seams. Don't expect it to hold up to fatigue cracks like metal expansion joints, nonmetallic failures are often sudden and more expensive to repair than replace. What about that? Regular inspections are much more cost-effective than mending leaks afterwards.

Let's make one thing clear first: Although non-metallic compensators and metallic compensators are both called compensators, their installation locations are very different

Metals can carry high temperatures and high pressures, such as power station steam pipelines and refinery pipelines, but the strengths of non-metals are low pressure, large displacement and corrosion resistance. The typical scene is smoke duct. Two days ago, a customer called me and asked me if I could install a non-metallic compensator on the steam main pipe. As soon as I heard it, I asked him to stop quickly-the temperature of the steam main pipe started at least 300℃, the pressure was above 0.5MPa, and the non-metallic fabric layer was directly carbonized. I asked him to look at the "high temperature axial expansion joint" on our website, and that was the right answer. Therefore, if the location is not selected correctly, no matter how good the product is, it will be for nothing.

Where is the main battlefield of non-metallic compensators?

The chimney entrance of the power station, the inlet and outlet of the desulfurization tower, the inlet and outlet pipelines of the dust collector, and the kiln head and tail of the cement industry-in these places, the medium temperature is generally below 200℃, the pressure is slightly positive or negative, and the pipeline displacement is large (both lateral and angular). The metal compensator either can't bear the corrosion or the cost is ridiculously high. You go to the 'Non-Metallic Expansion Joints (Fabric Fiber Expansion Joints)' and 'Rectangular Non-Metallic Expansion Joints' on our site, which are specifically designed for these scenarios. For another example, the flue gas baffle door of desulfurization system (such as our 'desulfurization flue gas baffle door') is often equipped with a non-metallic compensator next to it. Why? Because there are sulfur dioxide and water vapor in the flue gas, the metal bellows will rust out in half a year, but the non-metallic fabric layer plus PTFE film can last for three to five years.

Many people think that non-metallic compensators are soft, just find a place to stuff them in. Wrong! It is most afraid of high temperature and high pressure. If the pressure exceeds 0.1MPa, don't put it hard. The non-metallic fabric layer can't bear the high-pressure bulge. We have encountered a customer who installed a non-metallic compensator on a blast furnace gas pipeline with a pressure of 0.2MPa. As a result, it leaked in half a year-the wrong position was selected, and no one could save it.

Rectangular pipes and shaped pipes: What nonmetallic compensators do best

Bellows can be used for round pipes, but rectangular air ducts-such as the rectangular flue of the sintering machine head of a steel mill or the rectangular flue duct of a power plant-metal bellows either can't be made or the price is sky-high. At this time, only non-metallic fabric compensators can be used. Our 'rectangular non-metallic expansion joint' specializes in this, and the installation position is usually in front and behind the fan inlet and outlet, and the baffle door, which is used to absorb thermal expansion and installation deviation. Note: Rectangular pipes are often limited in space, so the installation position of non-metallic compensators should reserve enough maintenance space, otherwise it will be troublesome to die when replaced in the future. I have seen a desulfurization tower renovation project. The compensator is installed close to the wall, and even the wrench can't reach in during maintenance. In the end, it can only smash the wall-tsk, can you die if you leave 30 centimeters more in the design?

Three Forbidden Areas of Non-Metallic Compensators

First, if the medium temperature exceeds 300℃, you don't think about it.Even high-temperature-resistant silicone cloth can't hold it, and the temperature resistance is about 260℃. If it exceeds this number, you have to use 'high-temperature axial expansion joint' or metal products with heat insulation layer. Some customers have to take non-metals to test the export of flue gas heat exchangers, and as a result, they smoke in a month.

Second, there are pipelines with serious accumulation of condensate or dust.Non-metallic compensators are prone to dust accumulation and corrosion. If the location is selected on a horizontal pipe, be sure to consider drainage or ash discharge measures. For example, in the horizontal flue behind the dust collector, there is a lot of dust in the flue gas, and the bottom of the non-metallic compensator will accumulate hard lumps and then wear the fabric layer. What to do? Either install it vertically or open an ash discharge port at the bottom.

Third, the pressure exceeding 0.1 MPa is the red line.Don't believe that "it's okay to exceed it a little". The design pressure of non-metallic compensators is slightly positive pressure. If the system pressure fluctuates greatly, it is necessary to install a pressure relief valve. Remember: the metal can carry 0.5MPa, and the non-metal exceeds 0.1MPa, just wait for the bulge to leak.

Actual Combat Misunderstanding: Non-metallic Compensators Can't Bear Thrust

Some people think that the non-metallic compensator is soft and easy to install, so they install it where it needs to withstand the blind plate force (thrust) of the pipe. Wrong! Non-metallic compensators can only absorb displacement and cannot withstand thrust. For example, at the corner of the pipe or when the valve is closed, the blind plate force will act directly on the compensator, and the non-metallic one can't bear it at all-the fabric layer will be torn apart. At this time, the fixing bracket should be added, or replaced with 'universal corrugated expansion joint' or 'large tie rod expansion joint'. Before selecting the position, calculate the pipe thrust. How does that count? Find the pipeline diagram of the design institute to see the thrust value between the fixed brackets. If it exceeds 0.1MPa, decisively give up the non-metallic scheme.

Final step: three steps to get the installation position

On-site working conditions vary widely. How to locate them specifically? Three simple steps: First, look at the pipeline diagram and find the pipe section between the two fixed brackets with the largest thermal displacement-that place is the candidate location for the non-metallic compensator. Second, confirm that the medium temperature and pressure fall within the parameters of the non-metallic compensator (refer to JB/T 12235-2015 standard). Third, avoid positions where condensation, dust accumulation and mechanical collision are prone to occur. If you are unsure, just ask us about the drawings for sales. The article on our website 'National Standard for Non-Metallic Expansion Joints' has detailed parameters.

By the way, when installing, be sure to align the direction of the arrow with the flow direction of the medium, otherwise the force direction of the fabric layer will be reversed, and it will collapse in less than three months. Alas, this kind of low-level mistake happens several times a year.