Specialized in manufacturing compensators, expansion joints, baffle doors

1. Why must the transportation of the compensator be fixed? How tragic are the consequences of being unfixed?

Let's tell you the truth first. Last year, a customer bought aUniversal corrugated expansion jointWhen loading, I felt that it was only a few kilometers anyway, so I was too lazy to tie it up. As a result, there was a sudden brake on the road, and the expansion joint rolled directly from the carriage. The bellows fell out of a pit and the flange was deformed. Go to the site to test, air leakage-directly scrap. Do you think it's a loss or not?

The compensator looked solid, but it was actually very delicate. WhetherMetal hose、Corrugated expansion jointStillNon-metallic expansion jointNone of their core components (bellows, fabric bands) can withstand severe impact and extrusion. If it is not fixed during transportation, bumps, sudden braking and turning will make the products collide in the car, ranging from scratching the surface coating to flattening the bellows, bumping the flange and damaging the sealing surface. Not to mention those with limit tie rods, such asLarge tie rod expansion jointOnce the limit bolt is loosened, the direction cannot be found during installation.

So, compensator transportation fixation is not a "do-or-don't" thing, but the last insurance from the factory. If you save a few minutes of bundling time, you may have to lose thousands of dollars of product money-I don't have to forget this account, right?

Second, check before loading: first distinguish which type of compensator is in your home

Before you start fixing it, you have to find out what the compensator is on the car. Different types of compensators, the method of transport fixation varies greatly. It is impossible for us to bundle steel barsrubber compensatorRight?

• Metal hoses: IncludesPTFE-lined hose、Special hose for vacuumEtc. It is characterized by slender, soft, and most afraid of flattening and twisting.
• Corrugated expansion joint: IncludesCorrugated expansion joint for power station industry、Metal Corrugated Expansion Joints in Cement Industry、High temperature axial expansion joint、Direct buried (fully buried) type expansion joint、External pressure single axial expansion joint、Compound hinge transverse expansion joint、Straight pipe pressure balanced expansion joint、Curved tube pressure balance expansion joint、Compound straight pipe bypass pressure balanced expansion joint、Sleeve type pipe expansion jointEtc. This part of products usually has bellows and flanges, which are most afraid of bumps and lateral forces.
• Non-metallic expansion joint: IncludesRectangular non-metallic expansion joint、Non-metallic expansion joint (fabric fiber expansion joint)、Rubber PTFE compensatorEtc. It is characterized by fear of moisture, piercing by sharp objects and heavy pressure.

And there's alsoRound Flap Door (Double Seal)、Double-sealed single-axis circular baffle door、Flue gas baffle door、Desulfurization flue gas baffle door、Manual plug-in insulation door、Electric plug-in insulation door、Single-axis double-flapper doorThese products, although not exactly compensators, should also be treated as metal pieces when transported, and pay attention to protecting the sealing surface.

How to judge quickly? The easiest way: see if there is a bellows in the appearance-those with bellows are basically corrugated expansion joints; If the outer skin of the hose is wrapped with a metal braided mesh, it is a metal hose; If it is a cloth or rubber square/circular loop band, it is non-metallic.

3. Three steps of fixed operation: bundling, cushioning and limiting, none of which can be missed

Okay, I know what goods are on the car. Let's talk about the specific operation. Don't be too long-winded, these three steps are indispensable:

Step 1: Strapping

Use packing tape or nylon tightening tape, never use wire rope-wire rope will strangle the surface of the product. The binding point is selected at the root of the flange or at the reinforcing ring, avoiding the bellows and hose body. ForMetal hoseIt is necessary to put a protective sleeve (foam tube or rubber tube) on the outside of the hose and then tie it, otherwise the tightening belt will be directly strangled on the metal braided net, which will easily break the network cable.

How to master the binding strength? Subject to the fact that the product cannot be moved in the carriage, but do not strangle until it deforms. Think about it,Metal rectangular expansion jointThe corner is very fragile to begin with. If the bundle is too tight, the corner will be deflated directly, and the flange surface will be uneven when installing.

Step 2: Pad support

Strapping alone is not enough. Wooden or rubber pads should be placed on the floor of the carriage, and the products should be overhead to avoid direct contact with the metal floor-especially in rainy days, if water is soakedNon-metallic expansion jointThat ring belt sucked water, and it was moldy and cracked as soon as it was installed at the scene.

For products that are stacked in multiple layers (such as small boreUniversal corrugated expansion joint), each layer should be separated by foam board or cardboard to prevent the flange edges from bumping each other. Don't putrubber compensatorAndMetal hoseMixed with stacking, rubber parts are easily pressed out by metal parts.

Step 3: Limit

This step is the easiest to ignore. Many compensators come out of the factory with transport limits-such asexpansion joint tie rodAn adjustment nut on the adjustment nut, or a temporarily welded positioning plate. Check that these limits are secure before departure. If the limit bolt is found to be loose, it must be tightened, otherwise the bellows will expand and contract freely during transportation, resulting in uneven corrugation spacing.

In addition, for hinged expansion joints (e.g.Compound hinge transverse expansion joint), the hinge should be fixed with an additional wooden wedge to prevent the hinge from rotating itself during transportation and causing lateral force.

4. Fixing points of different products: metal hoses should not be flattened, corrugated expansion joints should not be bumped, and non-metal expansion joints should not be damp

This section is a little more detailed, and it is divided into products:

• Metal hose: It must be laid flat, and it is prohibited to stand up or fold in half. If the length of the hose exceeds 2 meters, add support points in the middle to prevent sagging and deformation. ForPTFE-lined hoseThe PTFE layer is particularly afraid of scratches, so the outer packaging must be kept when bundling, and hard cable ties should not be used.
• Corrugated expansion joint: WhateverCorrugated expansion joint for power station industryStillMetal Corrugated Expansion Joints in Cement IndustryProtective cover should be installed on the bellows (it can be wrapped with thick cardboard or foam board), and heavy objects are strictly forbidden to pile up. The flange face should be placed upward or sideways, and never let the flange be directly stressed. ForExternal pressure single axial expansion jointNote that the external pressure cylinder is easy to be hit and dented. It is recommended to add wooden strips on both sides of the cylinder for protection.
• Non-metallic expansion joint：Rectangular non-metallic expansion jointAndNon-metallic expansion joint (fabric fiber expansion joint)It must be wrapped tightly with waterproof membrane. If it is a rainy day at the time of delivery, the carriage should also be covered with tarpaulin. In addition, the non-metallic loop belt itself is elastic, so it should not be deformed under compression for a long time during transportation, otherwise it will not be recovered. It is recommended to fill the inside of the loop band with sponge support.
• Special Products：Rotary compensatorThere are rotating bearings, and the rotation angle should be locked during transportation to prevent the bearing from being injured during shaking.Double hinge expansion joint for air-cooled island vacuum pipelineThe size is large, so pay attention to the position of the center of gravity when loading to avoid rollover caused by eccentric load.

After unloading, I found that the product appearance was fine, but I couldn't install it once I installed it? Eighty percent is slight distortion in transit. Therefore, to fix this matter, it is better to be tight than loose, and it is better to have more than less.

5. Pits when unloading and removing fixing parts: Don't cut the cable tie in a hurry, first see if the limiting device is still there

When you arrive at the scene, don't rush to take scissors and cut all the straps. Do two things first:

First, check whether the limit rod and temporary positioning plate are intact. Before, some customers tried to save trouble, and after cutting the cable tie, the tie rod nut was loosened. As a result, the bellows popped out with a "bang" and almost hurt people. The correct method is: firstly confirm that the expansion joint does not displace during transportation, and then follow the steps in the installation instructions,Step-by-step removal of limiting device。 For products with tie rods, wait until the pipeline is connected and the installation reference is found before loosening the tie rod nut (refer to FAQ Article 12 "How to adjust the tie rod nut of expansion joint").

Second, see if there is any damage. EspeciallyNon-metallic expansion jointIf water stains or damage are found on the outer packaging, immediately unpack the check ring to see if it is not damp. If the loop is already wet, it needs to be dried in a ventilated place before installation, otherwise it will bulge and crack when heated.

Don't be brutal when unloading the goods. The sling should be hung on the flange or lifting lug, and never strangle it directly on the bellows. Large-ticket products (such asLarge diameter thick wall expansion joint) To use a special hoisting balance beam, single-point hoisting can easily lead to the deflection of the center of gravity, and no one will pay for it if it falls.

Compensator Transport FixedThis matter looks small, but one oversight is enough for you to drink a pot. From loading inspection to unloading and disassembling parts, each link follows these five steps to ensure that your compensator arrives at the site safely. Remember that?

Compensator Storage Raiders: Improper Storage and Direct Scrapping? These 5 Steps Help You Save Wasted Money

To be honest, the compensator looks pretty solid, but if you don't store it properly, it will be scrapped much faster than you think. A customer called the other day and said that two-year-old pieces had been dug up in the warehouserubber compensatorWhen I touch it, the rubber surface is all sticky, like chewed gum-waste. Tens of thousands of dollars have been wasted like this. Do you feel distressed?

Today, let's break it up and talk about itCompensator storage requirementsFive steps, each step has operation details, follow it, at least three years to keep your inventory good. Don't be too long-winded, the last trick to check the list is especially critical.

Step 1: Choose the right place to store it – temperature and humidity are invisible killers

You must not putcompensatorThrow it in an open corner or in a damp garage. Especiallyrubber compensatorAndNon-metallic expansion joint (fabric fiber expansion joint)These two categories are most afraid of two things: direct sun and humidity.

UV rays can make rubber age, harden, and crack. What about fabric fibers? When the moisture bubbles, it will mildew and rot directly. Do you thinkMetal bellowsIs it all right? Don't be careless. If the warehouse is near the acid-alkali storage tank area, and there is acid-alkali gas in the air, the stainless steel will still rust-don't ask me how I know, in the corner of the chemical plant warehouseUniversal corrugated expansion jointIt's a tragedy.

How to do it specifically?

• Be sure to store indoors, the temperature is controlled between-20℃ and +40℃, and the relative humidity should not exceed 80%.
• Stay away from radiators and air-conditioning outlets, the temperature difference fluctuates too much, and the seals will accelerate aging (such asPTFE compensatorThe sealing ring is crispy in a few months).
• You can only put it outside? Okay, set up a rainshade, and the bottom is raised by more than 200mm, otherwise the ground will be damp,Direct buried (fully buried) type expansion jointThe flange surface is the first to show you.

Tips:Do you have an area in your warehouse near acid and alkali storage tanks? If you have it, hurry upMetal hose、PTFE-lined hoseMove away, even a wall is not safe.

Step 2: Don't unpack the packaging too early-the original packaging is the best protection

As soon as the goods arrive, many masters are anxious to tear the plastic film and unpack the wooden box, and they still chant "check it". When you really want to install it, you will find that the flange surface is knocked in a pit, the bellows is all dust and oil,expansion joint guide tubeThe edges are deformed. You say it was wrong or not?

The rust-proof paper, desiccant and buffer foam in the original factory packaging are according to the manufacturersCompensator storage requirementsDesigned, it is a hundred times more reliable than the wrapper you temporarily find.

1. After arrival, check the model and quantity first, confirm that it is correct and put it back in its original place.
2. The packaging box is marked with "No trampling" and "Rain-proof and moisture-proof". It is best to write larger points with a marker.
3. With flanged protective coverMetal hoseAndDirect buried (fully buried) type expansion jointDon't remove the protective cover in advance.
4. When you need regular inspection, only open a small opening to see the appearance, and seal it back immediately after reading it. Don't try to save trouble and leave it open.

Note:PTFE compensatorAndPTFE-lined hoseThe inner lining layer is very delicate. Once the package is broken, dust will drill in, and it will leak after installation. I have seen a case, just because the packaging was broken, it leaked after three days of running, and it cost more than 60,000 yuan to replace it.

Step 3: Anti-deformation support – especially for metal bellows and rubber compensators

Have you seen one that has been kept for a yearBellowsInto *? That's the consequence of not doing support.Metal compensatorAndrubber compensatorThey are all elastic. If they are stacked vertically or laminated for a long time, the ripples will deform permanently, and they can't expand and contract normally when installed-do you think it's irritating?

• All compensators must be placed horizontally and stacking upright is strictly prohibited.Large diameter thick wall expansion jointAndCompound hinge transverse expansion jointThis kind of long guy should be evenly supported by brackets, with a fulcrum every 1.5 meters, so don't save money on brackets.
• rubber compensatorAndRubber PTFE compensatorThe inside should be inflated or stuffed with clean soft filler to prevent collapse. My recommended method: stuffing rags in, not newspaper (stuck to rubber after moisture).
• Sleeve type pipe expansion jointThe sliding sleeve part of the sliding sleeve must be kept in a free state. Do not tie it with iron wire, otherwise the sliding surface will be stuck.

And guess what? Two days ago, a client placed a boxRotary compensatorIt leaned against the wall vertically, but as a result, the top flange was directly crooked, and the bolts couldn't be screwed up during installation. In the end, it had to be returned to the factory for repair. The round-trip freight plus repair cost was 2,000 yuan gone.

Step 4: Turn over and check regularly-rubber parts and fabric fibers are afraid of pressure and moisture

Don't think let's just let it go. Compensators that are in stock for more than three months have to be doubled every two months. EspeciallyNon-metallic expansion joint (fabric fiber expansion joint)And rubber products, long-term immobility is easy to produce permanent compression deformation due to local compression-this is called "indentation memory", which can't be recovered.

Specific checklist (printed out and posted on the warehouse wall):

• See if the outer packaging is damaged, damp or eaten by insects. Mice love to chew on packing boxes, and when they bite, they will get ashed.
• Open the package to check whether the rubber surface is cracked or sticky-press it lightly with your finger to see the rebound, and it will be wasted if it does not rebound when pressed.
• Metal bellowsAre there any rust spots on the exterior? EspeciallyUniversal corrugated expansion jointAndCorrugated expansion joint for power station industryStainless steel will also rust-in the chloride ion environment, 304 stainless steel still can't bear it.
• Flange sealing surface,expansion joint guide tubeAre there any bruises on the edges? If the guide tube is deformed, it will directly affect the flow direction of the medium, and in severe cases, it will cause vibration and abnormal noise.
• Are the tie rods and nuts rusty? Don't forget a common occurrence:Function of expansion joint tie rodIt is a limit, and it may not be twisted after rusting, so it can't be adjusted during installation.

Note:If slight rust is found, apply anti-rust oil after polishing with fine sandpaper. Never use acid wash. Pickling will destroy the passivation film on the surface of stainless steel and accelerate corrosion.

Step 5: Final inspection before installation-pull rod, guide tube, flange surface must not be missing

It's finally going to be packed, don't rush to unpack it. It takes less than five minutes to do three things first:

1. Check whether the model is consistent with the pipeline design. For example, what you want to pretend isDouble-sealed single-axis circular baffle doorAs a result, the warehouse was takenSingle-axis double-flapper doorWaste half a day's effort and still have to change.
2. Check that the transport limiter is still in place. Many expansion joints come from the factory with temporary tie rods or support blocks (e.g.External pressure single axial expansion joint), these must not be disassembled before installation, otherwise the bellows will be pulled out during transportation. However-after installation, it must be removed according to the instructions, otherwise the compensator will not work. Have you ever seen a temporary tie rod not removed after installation? As soon as the pipe expanded, it exploded.
3. Clean flange sealing surfaces. Wipe the anti-rust oil and packaging debris clean and check for scratches. EspeciallyHigh temperature axial expansion jointAndSpecial hose for vacuumEven a scratch on the flange surface may leak.

Final reminder:For compensators stored for more than two years, even if the appearance is fine, it is best to contact the manufacturer for a pressure test or stiffness test. After all, rubber and seals will age naturally, and it costs money to install and replace them-downtime losses are the real big head.

All right, five steps. Save this article for next purchaseCompensator storage requirementsWhen you don't understand, dig it out and read it again. Remember, storage takes care and installation can be worry-free.

Compensator debugging steps, follow no error

A customer called the day before yesterday and said they had installed a new one in their factoryUniversal corrugated expansion jointAs a result, it leaked as soon as it was turned on. As soon as I heard it, I knew that it was probably that the limit screw was still screwed and unremoved. You say it was wrong or not? The compensator looked simple, but there were many ways to adjust it. Today we'll break it apart and crumble itCompensator debugging stepsMake it clear thoroughly. If you follow these six steps, you will be sure to make no mistake.

Step 1: Don't worry when you get the compensator, check the model and appearance, and remove the screw that should be removed

Equipment arrived? Don't rush into the pipe yet. The first step is the most important —Check model number。 Do you see if the model number on the nameplate is consistent with the design drawings? For example, what you buy isHigh temperature axial expansion jointAs a result, arubber compensatorThat certainly won't work. The appearance also has to be swept: did the bellows bump? Is there a scratch on the flange surface? Is the deflector distorted?

Screw removal。 Almost allMetal corrugated expansion jointWhen leaving the factory, the bellows will be locked with the limit screw to prevent damage during transportation. If you install it without disassembling it, the bellows can't be expanded or contracted at all, and it will burst directly when it heats up. How far? It's simple-loosen all the nuts on the screw, and then pull the screw out or put it in the longest position to allow the bellows to move freely. Pay attention to keep these screws well, and they may be used in future maintenance.

Tips:Some manufacturers will mark the screw, and you see it to remind you to "dismantle it quickly".

Step 2: Do pre-compression or pre-stretching according to the direction of the pipe, don't do it in the opposite direction

Many people stumbled over this step. The compensator should be pre-deformed in advance to adapt to the thermal expansion and contraction of the pipeline. Specifically, whether it is pre-compressed or pre-stretched depends on the temperature and environment when the pipe is installed.

For example, steam pipe, when the temperature is high during operation, the pipe will extend, then you installMetal hoseOrDirect buried (fully buried) type expansion jointDo it when youPre-stretching-Stretch the compensator a little longer to reserve space for the pipe to shrink. Conversely, if it is a cryogenic pipeline (such as a liquid nitrogen pipeline) and the pipeline shrinks during operation, you have to doPre-compression。

Then how to judge the direction? The easiest way:See the installation instructions given by the manufacturerThe amount and direction of the pre-deformation will be written on it. If not, you pre-adjust it at 50% of the design displacement value of the pipe. Use special tools when adjusting, don't pry the bellows, it is easy to damage.

Note:Pre-stretched or pre-compressed dimensions must be measured with a caliper, don't rely on feel. If you skew a few millimeters, you will be in great trouble later.

Step 3: The gasket should be centered when the flange is connected, and the bellows should be avoided when welding. Pay attention to the guide tube arrow

Then there is the installation link. If it is a flanged connection,Gasket must be centered。 The gasket is biased, and it will be squeezed and deformed as soon as the bolt is tightened, and it will leak 100% later. The gasket material should also be selected correctly-metal winding pads for high temperature steam, corrosive mediaPTFE compensatorMatching PTFE gasket.

If it is welding, pay attention to:The welding current must never pass through the bellows。 The ground wire of the welder should be connected to the pipe, not to the flange of the compensator. The arc will break through the thin bellows wall, and the compensator will be wasted directly. When welding, the bellows should be wrapped with a damp cloth or asbestos cloth to prevent welding slag from splashing and burning.

And the deflector tube. Mostlyexpansion joint guide tubeThere will be an arrow on it, and that arrow indicatesDirection of medium flow。 Installed backwards, the guide tube will not only fail to divert the flow, but also hold up impurities and accelerate wear. Especially lined products such asPTFE-lined hose, the direction of the arrow is installed backwards, and the PTFE layer can easily be washed off. If you take a closer look, the arrow usually says the word "flow direction". Don't pretend to be reversed.

Step 4: Cold tightening and tie rod nut adjustment, different compensator adjustment methods are different

This step is technical work. Let's start with what "cold tightness" means. Cold tightening is to artificially tighten or push open the pipe at room temperature, so that the compensator is stressed in advance. The purpose is to reduce the maximum stress of the pipeline during operation. The cold tightness is usually calculated according to 50% ~100% of the design displacement, which will be written on the specific numerical design drawing.

Let's talk about the tie rod nut. Different types of compensators have completely different adjustment methods:

• Universal corrugated expansion joint: The tie rod mainly plays an auxiliary support role, and the nut only needs to be loosened to not restrict the axial movement of the bellows, so it does not need to be screwed to death;
• Large tie rod expansion joint: There are two nuts on the tie rod, one locking and one adjusting. When adjusting, loosen the locking nut, then rotate the adjustment nut to compress or stretch the bellows to the specified displacement, and then tighten the locking nut. Pay attention to the synchronous adjustment of the tie rods on both sides, otherwise the compensator will be crooked;
• Compound hinge transverse expansion joint: Its pull rod is a hinge structure, and the nut only plays a role in fixing the position of the hinge. When adjusting, it is necessary to ensure that the hinge rotates flexibly;
• Rotary compensator: There is no pull rod, and it is adjusted by rotating sleeve. Make sure the sealing surface is clean and lubricated.

There was a previous article devoted toHow to adjust the tie rod nut of expansion jointYou can flip through it. In short, check after adjustment: Are each nut evenly stressed? Is the bellows twisted?

Step 5: Take your time to boost the system pressure, and stare at the pressure gauge to see if there is any leakage when holding pressure

After installation and debugging, start pressure testing. Don't take this step in a hurry.System boost should be slowIt is recommended to be staged: first rise to 30% of the design pressure, stop and check it again; No problem go up to 60% again and check again; Finally rise to the design pressure (or test pressure). Each boost is spaced at least 5 minutes apart to allow the pressure to stabilize sufficiently.

During the pressure holding period, you mainly focus on two things: One ispressure gaugeAnd see if the pointer keeps going down. If the pressure drops quickly, it means there is a leak. The other isCompensator itselfSee if the bellows has any abnormal bulging and deformation. Especiallyrubber compensatorAndRubber PTFE compensatorRubber parts are prone to bulge and break under overpressure, so be careful. If a leak is found, immediately relieve the pressure and treat it. Never screw the bolts with pressure.

Note:If the pressure test medium is water, the water should be drained clean after the test, especially in winter, to prevent the corrugated pipe from freezing and cracking. Some customers try to save trouble and not drain water, but the next day they find that the compensator is cracked. Is it a loss?

Step 6: Inspect more in the first week after operation, listen to the sound and watch the displacement, and find and deal with problems early

The first week after the equipment is officially in operation is the most prone to problems. At this time, you should go to the scene more often and do three things:

• Listen to the sound: Get close to the compensator to listen for a "fizz" of air leakage, or a "rattle" of metal rubbing. The latter may be that the tie rod nut is loose and the bellows hits the wall;
• Look at displacement: Make a mark on the compensator shell, and measure the distance during each inspection to see if the actual displacement is within the design range. If the actual displacement exceeds the design value, there is a problem with the pipe support or guide;
• Touch temperature: Feel the surface temperature of the compensator with the back of your hand. If it is locally overheated or overcold, it may be that the insulation layer falls off or the medium flows unevenly.

Some power plant installedCorrugated expansion joint for power plant industryOn the third day of operation, I heard an abnormal noise, and it was checked that the solder joint of the guide tube fell off and was stuck in the bellows. Fortunately, it was found early and didn't cause an accident. You see, more inspections, how much can you save on maintenance costs?

Compensator debugging stepsNot rigid dogma, every device has its own temper. If you are unsure, ask the manufacturer's technical support directly, and don't think about it yourself. After all, safety comes first, do you think that's the case?

Compensator flushing precautions: If these 5 steps are done wrong, the equipment will have to be reworked

Two days ago, I met a customer, and I called in a hurry to say that the newly installed compensator was wasted-the bellows was deflated directly after flushing, and the tie rod also collapsed. Only after asking did he know that he took the water gun for washing the fire pipe and rushed at the rubber compensator, and the pressure was adjusted to 0.8MPa. Alas, I've seen this too much. In fact, compensator flushing is not as mysterious as you think, but there are pits in every step. Today, let's break it up and crumble it, and explain these five steps clearly. You follow it and at least save money on rework.

Step 1: Find out what material the compensator in your hand is made of-metal, rubber, non-metal, and the rinsing method is completely different

Don't open the water valve as soon as it comes up. You have to look at the nameplate or the contract first to determine what the compensator is made of. If it isUniversal corrugated expansion jointOrCorrugated expansion joint for power station industryThis kind of metal is okay with pressure and temperature resistance, and ordinary water flushing is no big problem. But if you run intorubber compensatorOrRubber PTFE compensatorThen you have to be careful-rubber is afraid of oil, high-temperature water, and even more afraid of high-pressure water column.

Another category isNon-metallic expansion joints (fabric fiber expansion joints)AndPTFE compensatorTheir weak link is at the skin and flange junction. If you flush it with a high-pressure water gun, the fiber layer will be directly layered, and it will be wasted. So how to do it? First turn through the product information and see the maximum flushing pressure written by the manufacturer. If not, follow the steps below.

Step 2: Preparation before flushing-do you remove the deflector or not? Do you want to loosen the tie rod nut?

Many people will forget this step. Let's start with the deflector. We talked about it earlierSpecific Function of Expansion Joint Guide Tube-It mainly diverts flow and protects bellows. If there are impurities in the pipe (such as welding slag and rust), the impurities will get stuck between the guide tube and the bellows during flushing, wearing the bellows through. So advice: If it is the first time the new pipe is flushed, it is best to remove the deflector (provided you can remove it). If it can't be disassembled, make sure that the rinsing medium is clean and the flow rate is not too fast.

Let's talk about the tie rod nut. And guess what? Many people find that the compensator is deformed after rinsing, just because the tie rod is locked too dead. The correct way to do this is: before rinsingExpansion joint tie rod nutLoosen to the initial position when installed (generally marked at the factory) to allow the bellows to expand and contract freely. If the tie rod is used to limit the position, then loosen the nut to leave a 2-3mm gap. How exactly to adjust? You can read our previous Q&AHow to adjust the tie rod nut of expansion joint。 Remember: flushing is not a pressure test, don't use a pull rod to harness the pressure.

Step 3: Selection of flushing media and pressure-water pressure, air pressure, or chemical cleaning? How much pressure is going to be bad?

Okay, the material is confirmed, and the preparations are done. Now select media. In most cases withClearwaterJust do it, and the water temperature should not exceed 60℃. If there is oil in the pipe, consider adding a neutral cleaning agent, but remember-never use it onrubber compensatorOn, rubber is afraid of solvents. Air pressure flushing Don't use it! Unless your equipment design allows, pressure relief after compressed air is pumped in can easily bulge the bellows. How do you set the pressure? refer toMetal hose pressure standardAnd the design pressure on the nameplate of the compensator, the flushing pressure should preferably not exceed 1.2 times the design pressure. For example, a design pressure of 1.0MPaUniversal corrugated expansion jointThe flushing pressure is 0.6MPa at most, and the bellows can't stand it anymore. Pay special attention toSpecial hose for vacuumSuch thin-walled parts may deflate when the pressure exceeds 0.2MPa.

If what you encounter isDesulfurization flue gas baffle doorOrFlue gas baffle doorFor this type of sealing structure, don't flush the sealing surface with high-pressure water, which will damage the sealing strip. Just rinse the exterior with low pressure water.

Step 4: Practical points in the flushing process-sequence, flow rate and time. If one is not right, the bellows will deflate

From branch to main, from low to high. Why? Avoid backward water from heights. You flush the branch first and then open the main valve so that the dirt doesn't flush into the compensator.

How to control the flow rate? Look at the water. Don't be like a water gun. There is a critical point of laminar flow inside the bellows. If the flow speed is too fast, vortex will form, which will vibrate the bellows. A native method: put your hand on the outer wall of the pipe to feel it. Slight tremor can be done, but violent jitter means that the flow rate is too high. In terms of time, flush each section of pipe for 10-15 minutes until the water is clear. Don't be quick, I've seen people rush for half an hour, and it turns outPTFE-lined hoseA piece of the lining was washed off directly.

Special attentionLarge diameter thick wall expansion jointAndDirect buried (fully buried) type expansion jointThis kind of big guy, it is best to blow the debris in the pipe with compressed air before flushing, otherwise the rust will be blocked in the bellows trough, and you won't be able to flush it out.

Step 5: Check and reset after flushing-don't rush to turn on the machine, first see if there are any leaks or deformations in these places

After the water is finished, think it's done? That's naive. Don't rush to put the system into operation, do three things:

• Look at the leak: Focus on checking the flange connection, guide tube weld and tie rod nut root. Take a flashlight. If there are dripping traces, it means that the seal has failed. Especiallyrubber compensatorAndRubber PTFE compensatorThe rubber is easy to shrink after being blistered, and the flange gasket should be re-tightened.
• Look at deformation: Stand on the side to see whether the wave pitch of the bellows is uniform. If you find that a certain wave pitch is significantly larger than others, it is that the bellows has been washed out. You can measure it with a caliper, and if the deviation exceeds 5%, you have to change it. In additionRotary compensatorAndSleeve type pipe expansion jointHas the sealing packing of this rotating piece been flushed out by water? You will know when you look at it.
• reset tie rod: Finally, don't forget to restore the tie rod nut to working condition (that is, lock it to the design position). If this step is missed, the compensator will fail directly as soon as the system runs.

Non-metallic expansion jointIs there any blistering on the skin? Fabric fiber expansion joints will expand when exposed to water, dry and shrink again, and are prone to cracks. If you find a bulge in the skin, you have to remove it and dry it before putting it back in.

Tsk, after saying so much, in fact, the core is one sentence: find out what model of the compensator in your hand is before rinsing, and don't use general thinking to set it. If you haveDouble hinge expansion joint of air-cooled island vacuum pipeOrCompound hinge transverse expansion jointFor this special model, it is best to flip through our product information before rinsing, or ask the manufacturer directly. After all, once reworked, the labor cost and material cost add up to buy another one.

Step 1: Confirm the type of compensator you are using – metal, non-metal, or rubber?

Don't get started in a hurry, first find out which gods are installed on your pipes. Compensators looked similar in looks, but they were made of different materials, and their temper and temperament were far different. What do you haveMetal hose、Universal corrugated expansion jointStillCorrugated expansion joint for power station industry？ YesNon-metallic expansion joint (fabric fiber expansion joint)Stillrubber compensator？ Or the one with PTFERubber PTFE compensator？

How to distinguish? Just take a glance with your eyes: metal (such asHigh temperature axial expansion joint、External pressure single axial expansion joint) The surface is bright, hard to the touch, and usually rippled. Non-metallic (likeRectangular non-metallic expansion joint) It feels like thick cloth, soft and flanged. The rubber one is more direct, dark, elastic, and deformable when pinched. If you seeSleeve type pipe expansion jointThat's another structure-compensated by sleeve sliding. Before determining the type, don't do any maintenance actions, otherwise it will be easy to make jokes.

Step 2: Daily inspection-four-step method of seeing, listening, listening, touching and measuring

A daily stroll at work doesn't take much time, but it saves money on major repairs. Come on, do it:

• look: Eye sweep. Metallic (such asDirect buried (fully buried) type expansion joint) Any rust spots, cracks, deformations? Non-metallic (esp.Non-metallic expansion joint) Is there delamination, peeling, scratching by something? Rubber type (rubber compensator) Are there any bulging, aging and sticky?Flue gas baffle door、Desulfurization flue gas baffle doorThese with baffles, look at the sealing surface for any air leak signs.
• Listen: Prick up your ears. The compensator should not make abnormal noise during normal operation. The hissing may be air leakage, and the clicking may be bellows and guide tubes (yes, that'sexpansion joint guide tubeThat thing) collided. Two days ago, a client said hisDouble hinge expansion joint for air-cooled island vacuum pipelineOld ring, it turned out that the tie rod nut was loose.
• Touch: Touch with gloves (be careful of scalds or frostbite). Is it right to touch the surface temperature? Such asSteam pipelineOn the compensator, a certain section suddenly cools, which may be internal scaling or blockage. Feel the vibration amplitude again, and put your hand on the flange connection to feel it. If you shake badly, there is a problem.
• measure: Take a ruler and measure. Measure the installation length of the compensator and compare it with the original data. Such asCurved tube pressure balance expansion jointOrCompound hinge transverse expansion jointIf the displacement exceeds the design value, it must be adjusted quickly.

Tips:The frequency of inspection depends on the working conditions. High temperature and high pressure (power station, chemical industry) recommended once a day; Normal temperature and low pressure (ventilation, dust removal) twice a week is sufficient. Don't be lazy or overdo it, or you won't remember whether or not there has been any change.

Step 3: Regular maintenance-cleaning, lubrication, tightening and tie rod adjustment

Maintenance is not a one-time thing, it has to be stuck at a time. What should I do in three months, half a year and one year?

Cleaning (every 3 months)

Take a brush or compressed air to blow off dust and oil. Focus on cleanupMetal rectangular expansion jointThe corrugated gap, where corrosive media are most likely to be hidden. Non-metallic (e.g.Rectangular non-metallic expansion joint) Don't flush with water, wipe with a dry cloth. Rubber compensator is more delicate, don't touch oil solvents.

Lubrication (every 6 months)

The parts that need to be lubricated are mainlySleeve type pipe expansion jointA sliding surface,Rotary compensatorThe rotating parts, and variousexpansion joint tie rodThe thread of. Use molybdenum disulfide grease, don't use ordinary engine oil, it will carbonize when baked at high temperature.

Fastening (every 6 months)

Check all bolts, nuts. Focus on the flange connections, andLarge tie rod expansion jointBoth ends of the tie rod. Use a torque wrench to screw to the specified value, don't rely on the feel. Take a look by the wayexpansion joint guide tubeThe fixing bolts are loose, the thing falls off, the medium directly washes the bellows, and the life is discounted in half.

Tie rod adjustment (when required)

“How to adjust the tie rod nut of expansion joint？” I'll go straight to the steps: first confirm whether the pipe is in a cold state. Loosen the locking nut and rotate the adjustment nut so that the tie rod is in the "pre-stretched" or "pre-compressed" position-see the design drawings for details. After adjusting it, lock it tightly. Notice,Universal corrugated expansion joint、Straight pipe pressure balanced expansion jointThese have tie rods, and the displacement should be checked after adjustment. If you don't understand, just turn the standards. Don't play fool.

Step 4: Quick judgment and handling of common faults

Don't panic when the fault comes. Judge before you start. Here's a quick check list for you:

• Air/water leakage: 80% of the corrugated pipe is broken or the flange gasket fails. Metallic (likeMetal hose、PTFE-lined hose) may be fatigue cracks; Non-metallic may be fabric layer wear. Emergency treatment: Clamp it with a clamp, but it still has to be replaced. Long-term use? Don't think about it.
• abnormal noise: There is a high probability that the guide tube is loose or the tie rod nut is loose. Disassemble and see. If the guide tube falls off, re-weld or rivet it back. IfCompound straight pipe bypass pressure balanced expansion jointThe internal structure is messed up, so you have to contact the manufacturer.
• Stuck/not moving: Generally, there are debris stuck inside, or the guide structure is broken. Such asElectric plug-in insulation door、Manual plug-in insulation doorThese with plug boards, if there is any dust on the track, it has to be cleared. If you can save it, clean it directly, and if you can't save it, change it as a whole.
• Deformation/bulge: Overpressure or overtemperature. Stop the car quickly and check the operation records. LikeHigh temperature axial expansion jointIf the deformation is serious, it means that the material has exceeded the tolerance limit and is directly scrapped.

Step 5: Lifespan is up? These points tell you it's time to replace

Compensators are not perpetual motion machines, they have to retire. I've seen many customers figure to save money, hold on to use, and as a result, the pipe interface is cracked. So when should I change it? Here are a few hard indicators:

• Appearance: Metal bellows have visible cracks, penetrating corrosion holes, or wall thickness reduction exceeding the design value by 30%. Large area delamination, burning and holes appear in non-metallic expansion joints. The rubber compensator is seriously aged, sticky, bulging and bursting.
• Performance: The amount of compensation is not enough. Such asDirect buried (fully buried) type expansion jointIt should have absorbed 30mm displacement, but now it can only move 10mm. The internal bellows may have been plastically deformed, and it won't take a few days to support it.
• temporally: According to the Q&A mentioned "Service life of expansion joint"- -The design life of general metal compensator is 15-20 years, and the actual use is 8-10 years depending on the working conditions; Nonmetals have a short lifespan, 3-5 years; The rubber needs to be inspected in 2-4 years. You have to have a figure in mind, and don't endure according to the design lifespan.

In addition,Gas bellows(For example, the kind on gas pipelines) The state has a mandatory requirement: it is usually changed once every eight years. Never overdue.

Okay, after these five steps, you are basically a half-assed compensator maintenance master. If you are unsure of anything, look through the product information on our website, such asMetal expansion joint weight table、Metal hose size comparison tableCheck it against the model number. If it doesn't work, just call the manufacturer and ask it-but don't ask the nonsense of "How long can I use this?" Only by reporting the inspection data can people give you accurate advice.