Specialized in manufacturing compensators, expansion joints, baffle doors

选型失误是寿命短的第一杀手——材质和结构决定了你能用几年

前两天碰到个客户，抱怨他们厂里的膨胀节两年就漏了，拆下来一看，波纹管都烂穿了。一问工况——高温蒸汽管道，压力1.6MPa，温度350℃，结果当初图便宜选了通用型波纹膨胀节，材质还是304不锈钢。这不是找死嘛？

选型这事儿，说白了就是“什么马配什么鞍”。高温工况老老实实上高温轴向型膨胀节，材质得用Inconel 625或者至少321不锈钢；腐蚀性介质比如脱硫烟气，那就得考虑衬四氟金属软管或者非金属膨胀节（织物纤维膨胀节），甚至橡胶补偿器都能扛一阵。颗粒冲刷严重的场合，比如水泥行业的风管，水泥行业金属波纹膨胀节必须带耐磨导流筒，否则不到半年就磨穿。

结构上更别马虎。轴向位移大的管道，直管压力平衡型膨胀节或者复式直管旁通压力平衡型膨胀节是正解；需要吸收横向位移的，复式铰链横向型膨胀节或者曲管压力平衡型膨胀节才是对的。选错了类型，就跟让短跑运动员去举重一样，报废是迟早的事。

安装环节的“隐形杀手”：拉杆调整不到位、导流筒装反，再好的膨胀节也白搭

设备选对了就能高枕无忧？太天真了。安装环节的坑，一个比一个深。最常见的就是拉杆螺母没调整好。膨胀节拉杆的作用是限制波纹管过拉伸或过压缩，但很多安装队直接把拉杆锁死，或者干脆没拆运输固定件。你猜怎么着？管道一升温，膨胀节根本没空间补偿，波纹管直接鼓包报废。正确的做法是：安装后拆除运输螺杆，然后根据补偿量调整拉杆螺母，具体怎么调，参考我们站内的“膨胀节拉杆螺母怎么调整”那篇文章。

还有个更隐蔽的问题——导流筒装反了。膨胀节导流筒具体的作用是引导介质流向、保护波纹管免受冲刷。但箭头方向装反，介质直接冲击波纹管根部，腐蚀和磨损速度翻倍。记住：箭头方向必须与介质流向一致。别笑，现场至少三成安装工人会犯这个错。

运行中的磨损与腐蚀：介质温度、颗粒冲刷、化学侵蚀，这些坑你踩过几个？

正常运行阶段，膨胀节不是装上去就能躺平的。介质温度超过设计值10℃，波纹管疲劳寿命可能直接打五折。颗粒冲刷？那更是软刀子割肉。有些水泥厂用普通金属矩形膨胀节，内部没加导流筒，半年下来波纹管壁厚从3mm磨到0.5mm，你说能不穿孔吗？

化学侵蚀更头疼。脱硫系统里的酸性冷凝液，对金属波纹管是致命打击。这时候要么选衬四氟金属软管或聚四氟乙烯补偿器，要么用非金属膨胀节（橡胶四氟补偿器也行），但必须注意橡胶老化问题。顺便问一句：你们厂膨胀节表面有没有出现点蚀、晶间腐蚀？如果有，说明材质选型就有问题，趁早换。

定期巡检不是走过场：波纹管裂纹、橡胶老化、非金属层剥落，早发现早处理

很多工厂的巡检就是拿着手电筒走一圈，什么也没看出来。其实膨胀节失效是有前兆的。金属波纹管表面出现细微裂纹或者“橘皮”状变形，说明已经接近疲劳极限了。橡胶补偿器或非金属膨胀节，注意看表面有没有变硬、龟裂、或者分层剥落。尤其是橡胶，受臭氧和紫外线影响，寿命三到五年到头了，到时间就该换，别等漏了再停机。

另外，检查拉杆和螺栓的预紧力有没有变化。膨胀节运行一段时间后，拉杆可能会松动，导致波纹管偏移。要是发现波纹管有偏磨痕迹，说明管道支架可能下沉或者补偿方向错了。早发现早调整，还来得及。

环境因素管不管？保温、支撑、排水做对了，寿命直接翻倍

环境因素常被忽略，但往往是压死骆驼的最后一根稻草。比如室外安装的膨胀节，不做保温，冬天低温下金属脆性增大，波纹管更容易开裂。再比如蒸汽管道上的膨胀节，如果没有合理的排水设计，冷凝水积聚在波谷处，形成“水锤”，冲击损伤波纹管。怎么解决？在低位设置排水阀，或者选用带排水结构的套筒式管道膨胀节。

支撑也很关键。膨胀节本身不承受管道重量，附近必须设置导向支架和固定支架。很多现场把膨胀节当成管托用，结果波纹管被压扁，三个月就废。你想想，一个几万块的膨胀节，因为几个几千块的支架没做好而提前报废，值不值？

什么时候该换别硬撑：失效前兆判断与针对性预防策略

膨胀节不是终身免维护的。出现以下几种信号，赶紧换，别抱侥幸心理：第一，波纹管有明显裂纹或穿孔；第二，非金属膨胀节的织物层大面积剥落，已经能看到内部保温棉或钢丝网；第三，橡胶补偿器表面硬化到按不动，或者有气泡鼓起；第四，膨胀节整体出现明显扭曲变形，说明管道位移已经超出设计范围。

根据介质特性和工况，提前选对类型（比如电站行业用波纹膨胀节、空冷岛真空管道双铰链膨胀节等专项产品），安装时严格执行规范，运行中定期检查、及时调整。如果条件允许，在关键位置加装位移监测传感器，实时看着波纹管的伸缩量，心里就有底了。

说白了，延长膨胀节寿命就三个字——选、装、养。选对，装好，养勤。做到这三点，服役十年以上不是梦。

非金属补偿器漏了？别急着换，先试试这几步补漏方法

前两天接了个电话，客户说他们除尘系统的非金属膨胀节用了半年就开始冒烟。拆开一看，烟气里的颗粒物把蒙皮磨了个洞——这种事儿在水泥、电力行业太常见了。非金属补偿器（也叫织物纤维膨胀节）漏了，你第一反应是换新的？别急，先搞清楚泄漏点，80%的情况现场就能搞定。

泄漏点在哪？三种常见位置

非金属补偿器用在烟气管道、脱硫系统，介质温度高、腐蚀性强，泄漏基本就三个位置：一是层与层之间的搭接缝，二是法兰连接处的密封面，三是导流筒与蒙皮的铆接点或焊缝。你猜怎么着？很多时候根本不是蒙皮本身破了，而是螺栓松了——法兰面漏气，拧紧就能解决。所以第一步别急着买新件，先拿手电筒照照，肥皂水刷刷，看气泡从哪冒。

介质含硫或者强酸碱，密封垫老化变脆，一碰就碎。这时候你得判断泄漏类型：是点蚀穿孔（小洞），还是密封面失效，还是整体疲劳开裂？不同情况对策完全不同。

补漏前的准备：材料选错等于白干

别拿随便什么胶水往上糊。本站有橡胶补偿器、橡胶四氟补偿器、非金属膨胀节等产品，补漏材料必须匹配工况。高温烟气管道用耐高温硅橡胶或氟橡胶密封剂，温度超过300℃就得换陶瓷纤维修补料。如果介质含酸碱，用四氟密封带，参考本站衬四氟金属软管的耐腐蚀思路。

补漏前一定要清理干净。油污、积灰、旧胶层都得铲掉，露出新鲜基材。拿丙酮或酒精擦一遍，等完全干燥再动手。不然补了也白补，两天就掉。

对了，法兰面泄漏先检查螺栓——很多时候只是热胀冷缩导致松动，拿扭矩扳手按原厂力矩重新拧紧就行。别一上来就动大手术。

实战三种补漏方法

方法一：小型穿孔或裂缝，用耐温胶泥+玻璃纤维布多层贴补。 先把胶泥涂在破口处，贴上裁剪好的玻璃纤维布，再用刮板刮平，确保没有气泡。贴一层等干透（通常4-6小时），再贴第二层，至少三层。最后在外表面刷一层耐温密封胶，形成保护膜。这个方法适用于直径小于20mm的穿孔。

方法二：局部破损面积较大，裁剪同材质的蒙皮替换。 本站有现成的非金属膨胀节蒙皮材料，按破损区域裁剪，搭接宽度至少50mm。用耐高温粘接剂涂在搭接面，粘贴后用不锈钢压条和自攻螺丝铆接固定。注意压条间距不超过150mm，铆接点要错开原结构孔位，避免应力集中。

方法三：整体外包？别乱来。 有人问能不能直接在外面包一层金属补偿器？不行。本站有高温轴向型膨胀节、通用型波纹膨胀节，但这些金属件是用于管道位移补偿的，结构和非金属蒙皮完全不同，硬包上去会限制热位移，反而加速损坏。更靠谱的做法是定制一段短节式的非金属膨胀节替换破损段，尺寸要和原管道匹配，订货时提供通径、温度、压力、位移量就行。

补漏后的测试和日常维护

补完不能直接投运，先做气密性测试。拿肥皂水或发泡剂刷在修补处，通入0.05~0.1MPa的压缩空气（非金属补偿器设计压力低，千万别超压），观察有没有气泡。如果没有气源，运行后用手感受漏气点，或者用红外热成像看温度异常——泄漏处温度会明显偏低。

每季度检查一次蒙皮表面，有没有起泡、脱层、变硬。尤其是在水泥厂，水泥行业金属波纹膨胀节旁边的非金属段，粉尘磨损是致命的。建议建立台账，记录每次泄漏位置和修复次数，积累数据才能判断什么时候该彻底换新。

什么时候该放弃修补直接换新？

同一部位修补超过两次，或者泄漏面积超过总面积的30%，就别再纠结了。非金属补偿器的设计寿命一般3~5年，温度、腐蚀、机械疲劳都会加速老化。另外注意，如果泄漏发生在与本站的烟气挡板门、电动插板式隔绝门连接的部位，要考虑系统振动是否过大。振动会导致蒙皮疲劳开裂，那补了也没用，得加装阻尼，或者换用带加强网的非金属膨胀节。

别为了省几百块补漏钱，结果泄漏扩大导致停机停产——损失可是几万块起步。该换就换，算总账不亏。

Metal expansion joint desoldering? Don't hurry to scold the manufacturer, the problem may lie in this

Two days ago, I met a customer who said that the metal expansion joint weld of their pipeline was cracked, and asked me if the quality was not good. Alas, who is not in a hurry when it comes to such things-media leakage, production line shutdown, or safety accidents. But let's say, don't rush to throw the blame on the manufacturer. For the problem of desoldering, we must first look at where the welding is located. Is it the bellows and end pipe connection? Or a deflector weld? Or is it a tie rod mount? The causes of desoldering in different positions vary a hundred and eighty thousand miles.

The cracking of the circumferential weld between the bellows and the end pipe is most likely due to fatigue or stress concentration. If the weld of the guide tube is cracked, it is mostly because the guide tube is worn through by the medium or the guide tube is installed backwards, causing the airflow to directly scour the weld. Tie rod bearing desoldering? You have to check whether the tie rod nut is loosened during installation, and whether the limit is regarded as a fixed support. And guess what? Many so-called "quality accidents" were checked over and over again. Either the installation team was fooling around, or the selection didn't match the working conditions at all.

The three most common pits for desoldering

First, fatigue.The pipeline system expands and contracts thermally every day, and the expansion joint expands and contracts repeatedly. Once the stress concentration at the weld exceeds the allowable value, cracks will slowly grow out. Especially the large-diameter thick-walled expansion joint or high-temperature axial expansion joint, the more extreme the working condition, the more sensitive the fatigue life. For example, the temperature of high-temperature flue gas pipelines in the cement industry often fluctuates above 400℃. Every time the bellows expands and contracts, the welds accumulate damage.

Second, corrosion.When there are chloride ions and sulfide in the medium, the weld seam will be corroded preferentially, and the strength will drop linearly. The expansion joint behind the desulfurization flue gas baffle door has a bad corrosion environment. If the right material is not selected or the corrosion resistance treatment is not done, the weld will become slag in less than half a year.

Third, the installation error.When leaving the factory, the tie rod nut was not loosened, the guide tube was installed backwards, and the cold drawing amount of the pipeline was not enough... These operations caused additional stress to be fully pressed on the weld. Many customers complained that "it took three months to desolder". As a result, when they went to the scene, they found that the direction of the guide tube arrow pointed to the opposite direction of the medium flow, and the airflow directly hit the bellows. Tsk, is this pot manufacturer wronged?

What about that?

Let's see the working conditions first. If it is a pipeline at normal temperature and low pressure, such as a general-purpose corrugated expansion joint, the cracking of the weld joint is probably a problem of the welding quality itself-the current is excessive, the welding electrode is wrong, and the groove is not handled properly. You have to re-weld if you should cut it off and re-weld it. Don't feel distressed. However, if it is a high-temperature steam pipeline or a high-temperature flue gas pipeline in the cement industry, desoldering is often a wrong selection. At this time, we have to consider changing the high-temperature axial expansion joint or the external pressure single axial expansion joint, so that the bellows can avoid the high-temperature area. Another situation: the displacement of the pipeline is too large, and the general-purpose type can't bear it at all, so it is necessary to use the double hinge transverse expansion joint or the straight pipe pressure balance expansion joint to share the stress.

On-site emergency treatment is also particular. Small cracks can be repaired in non-critical parts, but they must be welded with the same material electrode, preheated and controlled cooling speed. If the bellows itself is cracked, don't repair welding-the wall thickness of the bellows is thin, and it will burn through as soon as it is repaired, so replace it directly. In addition, it should be noted that before repair welding, check whether the guide tube is in good condition. If the guide tube is also worn out, the medium will directly wash the inner wall of the bellows, and desoldering is only a prelude. When replacing, it is best to check the adjustment status of the expansion joint tie rod nut simultaneously to ensure that the pre-tension or pre-compression meets the design requirements. As for how to adjust the tie rod nut? After screwing the nut to the limit position, reverse back half a turn to one turn, so that the expansion energy saving can expand and contract freely. Look at the design drawings for specific values, don't screw them blindly by hand feel.

Prevention is really worry-free

The selection stage is not cheap. When providing information to the design institute, write clearly the temperature, pressure, displacement and corrosive medium. For example, the expansion joint behind the flue gas baffle door has a high sulfur content in the medium, so corrosion-resistant alloy or PTFE-lined scheme must be used. In the installation stage, be sure to look at the direction of the arrow on the expansion joint (flow direction mark), and one end of the guide tube faces the direction of the medium. During the operation stage, check the appearance of the weld regularly, tap and listen to the sound, and do penetration testing if conditions permit. Don't forget, the life of the expansion joint is directly tied to maintenance-you let it run over the limit, and it will strike sooner or later.

In the final analysis, 80% of the desoldering of metal expansion joints are not deliberately cut corners by manufacturers. Find the root cause, prescribe the right medicine, change the type, repair the welding, don't curse your mother as soon as you come up. Pipeline safety depends on the cooperation of three rings of selection, installation and maintenance, and one less ring will lead to moths.

1. Where are non-metallic compensators used? Don't use it in the wrong place.

Non-metallic compensator (also called non-metallic expansion joint/fabric fiber expansion joint) is mainly used to deal with low-pressure and high-temperature pipeline systems such as flue gas, hot air and dust. To put it bluntly, where the metal expansion joint can't withstand high-temperature corrosion or large displacement, it should play. For example, the desulfurization flue gas pipeline of the power station, the kiln tail waste gas pipeline of the cement industry, the blast furnace gas pipeline of the steel plant, and even the flue gas purification system of the waste incineration plant-the temperature in these occasions is always five or six hundred degrees, and some instantaneous peaks can rush above 1000℃, and the metal parts are soft for a long time.

Unlike metal compensator, it relies on fiber fabric and rubber composite layer to absorb displacement, and does not generate thrust itself, which can save a lot of trouble in bracket design. But you have to put it on a high-pressure steam pipe? That is wrong-if the pressure exceeds 0.1MPa, you have to choose the type carefully, and don't use it as a high-pressure part. A customer in our station once wanted to use a rectangular non-metallic expansion joint on a 2MPa compressed air pipe, but before it even ran, the fabric layer bulged.

2. Find out these 4 parameters before installation, otherwise it will be in vain.

The first is the displacement-you have to calculate how many millimeters the thermal expansion and contraction of the pipe are offset, and calculate the axial, transverse and angular directions separately. Many on-site pictures save trouble, and they say "come to a 200mm one" when they open their mouths. As a result, the actual displacement is only 30mm, a small horse pulls a big cart, and the fabric folds age quickly. The second is the temperature-the highest temperature and instantaneous peak temperature of the medium directly determine which layer of fabric to choose: silicone cloth can withstand the temperature of about 200℃, fluorine cloth can reach 300℃, and ceramic fiber will be required if it is higher.

The third is the media composition. Have strong acids and bases? That has to be lined with PTFE, which is the "rubber PTFE compensator" or "PTFE compensator" on our station. The fourth is the installation space-rectangular non-metallic expansion joints for square pipes and rounds for round pipes, don't get confused. Two days ago, a customer welded a round one to a rectangular air duct. As a result, the seal was not tight and it took half a month to rework. You say it was wrong or not?

3. Installation steps and the details of the easiest rollover.

Hoist in place → Adjust bolt pre-tension → Weld or flange connection → Remove transport screw. But the worst thing about the rollover is-when will the transport screw be removed? Many people dismantle it as soon as it is installed, and as a result, the compensator is pulled out before the pipe is hot. Correct practice: Wait until the pipeline is installed, the bracket is fixed, and then disassemble it before trial operation. The FAQ of our station specifically mentioned "Does the screw of the expansion joint need to be disassembled?" That's what it said.

In addition, the direction of the guide tube must follow the flow direction of the medium, and the direction of the arrow should not be reversed. And guess what? A cement factory installed the guide tube backwards, and the high-temperature airflow directly washed the fabric layer, which was perforated in three days. We also talked in detail in the FAQ of our station that "the arrow direction of the expansion joint" is for this purpose.

4. In daily use, the three most easily overlooked pits.

Pit 1: Let the compensator bear the load.The non-metallic compensator only absorbs displacement and does not bear weight. The weight of the pipeline depends on the bracket. Even an elbow should be supported separately. Don't let it hang. Some site drawings save trouble, hang the valve directly on the compensator, and the flange leaks within a month.

Pit 2: Neglect insulation.The outer insulation layer not only insulates heat, but also prevents condensed water from corroding the fabric layer. However, many people think that "it can withstand high temperatures anyway" and don't pack it. As a result, the outside condenses and water seeps into the fabric, accelerating aging. Especially noticeable in winter.

Pit 3: Large compensator for small displacement.Some people choose oversized specifications for "insurance", which leads to wrinkles and accelerated aging of fabrics under low displacement. According to JB/T 12235-2015 standard, the working displacement of the compensator is preferably controlled between 60% and 80% of the rated displacement. You say that using a 200mm compensator to absorb a 20mm displacement, isn't that a waste of things?

5. When should I change? Don't wait until it leaks to dismantle it.

The life of a non-metallic compensator is usually 3-5 years, but depends on the operating conditions. If you find that the surface of the fabric layer is cracked, hardened, delaminated, or the flange bolt can't be tightened after it is loose (indicating that the sealing layer has collapsed), then you have to change it quickly. Another signal-the vibration of the pipe suddenly becomes louder, or there is an abnormal noise around it, which may be that the internal guide tube has fallen off. Usually check the appearance quarterly, focusing on welds and fabric overlaps.

If you want to save trouble, rubber compensators are cheaper than fabric compensators, but the temperature resistance is only about 100℃, so don't get confused. When encountering high-temperature flue gas, nonmetallic expansion joints (fabric fiber expansion joints) or rectangular nonmetallic expansion joints have to be used. In the final analysis, with the right selection, the right installation, and the maintenance keeping up, it is not a problem to use a compensator for five years.

What is radial force? Why do so many people fall on this

Anyone who designs pipelines knows that the biggest function of metal expansion joints is to absorb heat displacement. However, when the radial force was mentioned, many people began to be confused. Radial force, to put it bluntly, is the force that pushes the bellows perpendicular to the axis of the pipe, from the center outward or from the outside inward. Wrong direction, light bulge, worse bracket collapse, pipeline twist. Two days ago, I met a customer. A DN600 steam pipe was equipped with a universal corrugated expansion joint. As a result, the radial force was not calculated accurately. After three days of production, the corrugated pipe bulged like a toad's belly. Alas, this kind of thing is not rare.

Radial forces under internal pressure: Outward expansion is mainstream, but not so simple

As soon as the pressure inside the pipe comes up, the bellows expands outward like a balloon-this is the most intuitive direction of radial force, pointing from the central axis to the outer wall. But don't think it's just evenly outward. withUniversal corrugated expansion jointFor example, the radial force generated by internal pressure will make the wave peak expand outward and the wave trough contract inward. The magnitude of this force is directly related to the pressure and wave diameter. If the medium is high temperature and high pressure steam, the radial force has to be doubled instantly. What's more troublesome is that this force will be transmitted to the whole pipeline system, and if the constraint is not good, it can push the fixing bracket askew.

Don't ignore end effects

Where the ends of the bellows are close to the end pipe, the radial force distribution will change abruptly. Stress is concentrated there, and the ripples are more likely to crack. So a lotHigh temperature axial expansion jointThickened walls or reinforcing rings may be provided at the ends in order to hold the non-uniform radial forces of this piece.

Radial force reversal under displacement condition: axial compression, transverse tension, direction change accordingly

Internal pressure is only the basic working condition, and what really makes the radial force "discolor" is displacement. When the pipe is heated and elongated, and the expansion joint is axially compressed, the relative positions of the peaks and valleys of the bellows change, and the direction of the radial force will be partially reversed-the place that originally wanted to be pushed out may be retracted inward at this time. Conversely, if it is a lateral displacement (such as a pipe route turning), the radial force will become a complicated state of "pulling and pressing at the same time". At this time, useCompound hinge transverse expansion jointOrLarge tie rod expansion jointCan effectively restrain and avoid the radial force runaway.

I've seen a case in the cement industry, usingMetal Corrugated Expansion Joints in Cement IndustryOriginally, the axial displacement was handled well, but the radial force reversal was not considered after the lateral displacement was added, and the spacing between the guide brackets was too large, so the bellows was directly twisted into a twist. Tsk, it's more expensive to fix than to buy a new one.

Differences in Radial Force of Different Types of Expansion Joints: From Universal Type to Pressure Balance Type

Different structural designs, the performance of radial force is very different.

• Universal corrugated expansion joint: The radial force caused by internal pressure is the largest. If there is no guide tube, the bellows will easily become unstable under high pressure.
• Straight pipe pressure balanced expansion jointAndCurved tube pressure balance expansion joint: Most of the internal pressure thrust is offset by balancing the bellows, and the radial force mainly comes from media flow disturbance and installation deviation, which is relatively easy to control.
• Compound hinge transverse expansion joint: The radial force is concentrated on the hinge structure, and the bellows itself is more stressed, but special attention should be paid to the fatigue life of the hinge.
• External pressure single axial expansion joint: On the contrary, its bellows is compressed on the outside, and the radial force generated by the internal pressure is squeezed inward, in the entire reverse direction. Don't get confused when designing.

You see, it is also called an expansion joint, and the direction of radial force varies widely. When you don't see clearly when you select the model, you have to cry at the scene as soon as you sign the drawings.

Common consequences of misdesigning radial forces: bulging, twisting, stent collapse

The radial force is not counted correctly, how serious are the consequences? Tell me a few real things:

• bulge: The internal pressure radial force is too large, the bellows peak excessively expands outward, and the material forms permanent bulge after yielding. Common inLarge diameter thick wall expansion jointAlthough the wall thickness is large, the stress is concentrated in the zone of abrupt curvature change.
• Twisted: The direction of the radial force is inconsistent during lateral displacement, causing the bellows to twist like twisting a towel. Generally occurs in the middle of long pipelines, when the spacing between guide brackets exceeds the standard.
• Stent collapsed: The radial force is transmitted to the fixed bracket through the end tube, and if the bracket is not designed according to the thrust, it will tear the base directly. There was a desulfurization flue project last year, usingDesulfurization flue gas baffle doorAndNon-metallic expansion jointCombination, just because the radial force is not counted, the fillet weld of the steel support is broken.

These problems can actually be avoided by preliminary calculation. The point is, you have to know exactly where the radial force is pushing.

How to judge the direction of radial force during installation? Look at arrows, calculate thrust, set guidance

Don't have time to do finite elements for on-site installation? There are shortcuts, too.

First, look at the arrows.Products in the station (such asUniversal corrugated expansion joint) Before leaving the factory, arrows are basically made, and the direction of the arrows is the flow direction of the medium, which also corresponds to the main direction of the radial force after installation-the flow direction side is the peak expansion side, and the reverse side is the trough contraction side. Don't act backwards.

Second, count thrust.The internal pressure thrust formula is not complicated: F = p × A (A is the effective area of the bellows). However, the radial force has to be multiplied by a coefficient, which is related to the shape and height of the wave. In the stationStiffness and Calculation Formula of BellowsThe detailed algorithm is listed in the question and answer, so just apply it directly.

Third, set the guidance.Whether the radial force can be controlled or not, the guide bracket is the key. normalUniversal expansion jointThe first set of guide brackets is required to be Direct buried (fully buried) type expansion jointIt is another set of calculation logic to consider the influence of soil lateral constraint on radial force.