Find out what a non-metallic compensator does
To put it bluntly, non-metallic compensators are "soft joints" in the pipeline system. Thermal expansion and contraction, equipment vibration, installation deviation-if these displacements are hardened, the pipe will crack sooner or later. Non-metallic compensators rely on flexible materials (rubber, fabric fibers) to absorb these displacements, and by the way, they can isolate vibration and noise.
Compared with other compensators, its biggest advantage is that it is cheap and corrosion resistant. Metal expansion joints (like the one on our websiteUniversal corrugated expansion joint、Although high-temperature axial expansion joint (high-temperature axial expansion joint) has high pressure resistance, it will rust out in two or three years when it encounters acid-alkali flue gas and dust environment. Non-metallic ones can carry them instead. Specific classification:
- rubber compensator: It is used in room temperature water pipes and low pressure air pipes. It is cheap and elastic, but it is afraid of high temperature and oil.
- Non-metallic expansion joints (fabric fiber expansion joints): The temperature resistance can reach more than 1000℃, and it is the first choice for flue gas ducts and hot air ducts.
- Rectangular non-metallic expansion jointSpecially used for rectangular flue and air duct, it is common in power plant desulfurization and steel dust removal systems.
So you see, the first step in model selection is not to pat the head, but to figure out the working conditions. Is the medium flue gas or water? What's the temperature? Is it corrosive? If the direction is reversed, the money will be wasted.
Don't rush to do it before installing, check these four things first
Two months ago, a customer called to say that the compensator was leaking after three days of installation. When asked, the flange hole distance was 5mm different, so it was hard broken up. Can this not leak?
- Pipeline displacement: How many in axial, transverse and angular directions? Don't just look at the temperature, but also look at the direction of the pipe and the position of the fixing bracket.
- Medium temperature: Excessive temperature will cause accelerated aging of the rubber and brittleness of the fabric fibers. National standardJB/T 12235-2015The applicable temperature ranges for different materials are clearly defined in.
- Working pressureGenerally, non-metallic compensators can only be used at low pressure (≤0.1MPa). If the pressure is high, metal must be used.
- Flange Specifications: The center distance of the bolt hole, the diameter of the bolt and the form of the sealing surface must match the pipe flange. Don't believe "almost", it won't fit a millimeter away.
Order after the parameters are calculated accurately. On our websiterubber compensatorAndRectangular non-metallic expansion jointThere are standard specification sheets, so just compare and select the type directly. If you are really unsure, send the working conditions to the manufacturer and let them help you calculate.
Step-by-step installation steps: Details determine life
Installation looks simple, isn't it just screwing the bolts? Wrong. I've seen too many cases of leaks caused by reversed installation sequence.
Step 1: Flange alignment.The compensator flange and the pipe flange must fit naturally, and cannot be forcibly pulled together by bolts. If the misalignment exceeds 2mm, the pipe support must be adjusted.
Step 2: Bolt pre-tightening sequence.Symmetrical tightening, divided into 2-3 times, torque control within the range of instructions. Don't hit it with a wind cannon as soon as you come up. It's okay that the flange of the non-metallic compensator is made of steel, but the rubber or fabric layer can't withstand excessive local stress.
Step 3: How to adjust the tie rod nut?It's a technical job. The function of the tie rod is to limit the overstretching of the compensator. When installing, loosen the nut first, so that the compensator is in a free state. After the pipeline system is installed and the fixing bracket is locked, adjust the tie rod nut to retain the pre-compression amount required by the design. And guess what? Many people screw the nut to death when they come up. As a result, as soon as the pipe expands, the compensator can't move at all and tears directly.
Step 4: Is the screw disassembled or not?This question is asked every once in a while. Answer: The transport screw (used to hold the compensator against transport deformation) must be removed, otherwise the compensator will not work. While the screw on the pull rod is retained after adjustment in place, it provides limit protection. For details, you can see our websiteDo you need to remove the screw of the expansion jointThat question and answer explained it very clearly.
Three of the easiest places to roll over in actual use
The direction is reversed. Especially models with deflectors-such asNon-metallic expansion joints (fabric fiber expansion joints)The direction of the arrow of the deflector must point to the direction of the medium flow. On the contrary, the guide tube will not only fail to protect, but will also take a ride and accelerate the damage. About the role of the deflector, this site also has a special article.
Not enough pre-stretch left. It is written on the design drawing that it is pre-stretched 20mm, and the installer is too troublesome to install it directly. As a result, as soon as the pipe heated up, the compensator did not stretch enough, ripping the fabric layer. What about that? Measure it with a ruler when installing, it takes five minutes more and can guarantee five years of life.
Forgot to set the insulation layer under high temperature conditions. Although the fabric layer of the non-metallic compensator is resistant to high temperatures, if the pipe temperature exceeds 800℃ and there is no thermal insulation lining, the heat directly radiates to the fabric, and it will embrittle in a few months. The correct way to do this is to add insulation on the inside of the compensator or wrap insulation cotton on the outside. OurRectangular non-metallic expansion jointWhen used in power plant flue gas systems, there is generally an insulation option.
Don't be bothered with routine maintenance
Non-metallic compensators are not installed and done once and for all. Every three months, take ten minutes to take a look:
- Are there any bulging and wear in the fabric layer? The bulge indicates that ash or water may have entered the interior, and it needs to be dealt with quickly.
- Is there any aging crack in the rubber part? Pressing with your finger, hardening or appearing fine lines is a precursor to aging.
- Check whether the bolts are loose, especially under high temperature conditions, thermal expansion and contraction will attenuate the torque of the bolts.
Under normal working conditions, the non-metallic compensator can be used for 5-8 years. However, in the corrosive environment such as flue gas desulfurization, we have to keep an eye on the point-acidic condensed water seeps into the fabric and will be wasted in one year. It is recommended to useRubber PTFE compensatorOrPTFE compensatorAnd the corrosion resistance is much better.
Choose the right, install the right, and raise the right, and the non-metallic compensator is the intimate little cotton-padded jacket of the pipeline system. Save worry and money, and the key is not to be lazy on the details.