Let's talk about what the fluorine glue non-metallic compensator is?
To put it bluntly, it's the same as what we always sayNon-metallic expansion joints (fabric fiber expansion joints)It is similar in length-the main structure is still a non-metal ring belt plus a metal frame. But the key is that there is an extra layer of fluororubber (referred to as fluororubber for short) in the non-metallic layer. This thing can withstand the temperature to about 250℃, and its resistance to acid and alkali, oil and solvents is much stronger than that of ordinary rubber. Those old customers choose it, mostly because the pipeline is filled with strong corrosive media, such as desulfurization flue gas and chemical waste liquid.
Wouldn't you just put it on the metal bellows? Don't worry, the welds and corrugated roots of metal parts are prone to stress corrosion cracking in the environment of strong acid and strong alkali, and the cost is high and the installation weight is heavy. The flexible band of fluorine rubber non-metallic compensator can absorb multi-dimensional displacement, also reduce vibration and noise, and its price is more affordable than that of metal expansion joint. Of course, it is not a panacea either-high-pressure situations have to be cautious.
Where are the core strengths? Temperature tolerance and chemical stability are specialties
Ordinary rubber compensator is soft and brittle above 150℃, while fluorine rubber layer can withstand high temperature, and at the same time, it has the vibration and noise reduction ability of non-metallic expansion joint itself. Note, however, that its pressure-bearing capacity is inherently inferior to that of a metal corrugated expansion joint. Two days ago, a customer who was doing a desulfurization project asked me, "Can you use fluorine rubber compensator instead of metal expansion joint?" I asked him back, "Does your pipeline pressure exceed 0.5MPa?" If it is really high pressure, look at the one in our stationDesulfurization flue gas baffle doorOrCorrugated expansion joint for power station industryMore reliable.
Many people think that fluorine compensator can hold all corrosive media, but it is actually a big mistake. For example, in the environment of concentrated sulfuric acid, fluorine glue can't stand it, so PTFE has to be used. When designing and selecting, the composition of the medium is an iron law, not just by looking at temperature and pressure.
Compared with rubber PTFE compensator and rubber compensator, what is the difference?
Nitrile and neoprene, which are usually used in rubber compensators, are cheap but have poor temperature and corrosion resistance, and they can stop vegetation at 80℃. The rubber PTFE compensator is a rubber + PTFE composite, and the PTFE layer is excellent in corrosion resistance, but the fit should be careful-the PTFE layer and rubber are easy to layer and foam at high temperature. As for fluorine rubber compensator, the whole elastomer is fluorine rubber, which has good integrity and is suitable for working conditions with large temperature span (-20℃ ~200℃).
For example, in concentrated sulfuric acid environment, fluorine glue is better than tetrafluorine? No, in fact, PTFE is more resistant to strong acids, and fluorine glue is more suitable for organic solvents and alkaline environments. This knowledge point is confused by many engineers. I have seen a chemical plant that originally usedRubber PTFE compensatorThe benzene-containing solvent was transported, and as a result, the PTFE layer bulged. After replacing it with fluorine glue, it ran for two years without problems.
What pits should be avoided in installation and maintenance?
First of all, the general installation specification for non-metallic compensators (refer to JB/T 12235-2015) emphasizes that the direction of the deflector must be consistent with the flow direction of the medium, otherwise it will be quickly scrapped by erosion. Secondly, the fluorine rubber ring belt cannot be forcibly stretched when installed, it is less resistant to shear than ordinary rubber. Also, check the outer fabric fibers regularly for wear-even if the fluorine glue is not broken, the fiber layer is broken, and moisture seeps in and still corrodes the inner skeleton.
On our stationRectangular non-metallic expansion jointThere is a case in the product page: a fluorine rubber compensator was used at the outlet of the desulfurization tower of a steel mill. Because the limit tie rod was not installed, the high temperature expansion caused the frame to deform. Lesson! The limit rod is omitted directly by many installation units because it is troublesome. As a result, the lateral displacement of the compensator exceeds the limit and the ring belt is torn. Therefore, when installing, you must match the tie rod according to the drawings, and don't disassemble the adjustment nut. For specific operation, you can turn over the question and answer "How to adjust the tie rod nut of the expansion joint" in the station.
Finally, a selection suggestion: What scene closes your eyes? What scene don't touch?
Suitable scenario:
- Flue Gas Desulfurization (FGD) System: Temperature is about 150℃, contains acidic condensate, and fluorine glue is perfectly matched.
- Chemical pipelines transport halogen-containing organic solvents: such as carbon tetrachloride, chlorobenzene, and fluorine glue have excellent swelling resistance.
- Power Plant Air-cooled Island Vacuum Pipe: Although More RecommendedDouble hinge expansion joint for air-cooled island vacuum pipelineHowever, a size-matched fluorine rubber ring tape can also be used, provided that the vacuum degree does not exceed-0.05MPa.
Don't touch the scene:
- Steam pipeline: high temperature and high pressure (> 300℃,> 1.0MPa), please selectHigh temperature axial expansion jointOrExternal pressure single axial expansion joint。
- Systems with extremely high vacuum (Metal hoseOrSpecial hose for vacuum。
The strengths of fluorine glue are medium temperature, low pressure and strong corrosion. Don't take it as a panacea. When selecting a model, look through the product information of our site, such asrubber compensator、PTFE compensatorThose pages, comparing them, make me feel more confident.