Last month, an engineer at a chemical plant called and said they hadUniversal corrugated expansion jointAs soon as the furnace was started, it screamed harshly, and the workers on the spot were afraid to approach. The problem of abnormal noise of the compensator is not big or small-let it go, which can disturb the people at least, and the fatigue cracking of the bellows and media leakage at worst. Then the question arises: Where did this noise come from?
1. Resonance is the number one suspect
The bellows itself has a natural frequency. If the flow rate or pressure fluctuation frequency of the medium in the pipe is matched with it, it will trigger resonance. Pay special attention toCorrugated expansion joint for power station industryAndHigh temperature axial expansion jointThis kind of metal parts, the resonance under high elasticity is easy to produce high-frequency howling. How to check? It's simple – touch the compensator body with your hand. If the vibration sensation is obvious and the frequency is stable, nine times out of ten it is resonance. At this time, don't rush to change parts. First, adjust the rigidity of the pipe support or change the flow rate of the medium. If necessary, install a damping device outside the expansion joint.
2. Loose guide tube or liner
Many expansion joints are equipped with guide tubes (about the specific function of guide tubes, we have a special article on our station), which is used to protect the bellows from high-speed fluid erosion. Once the deflector weld cracks or the retaining bolts come off, it clatters like a broken gong in the airflow. Especially forFlue gas baffle door、Desulfurization flue gas baffle doorThe rearNon-metallic expansion jointOrrubber compensatorWhen the medium contains particles, the guide tube wears faster. Inspection method: After shutting down, disassemble the insulation layer and observe the interior with an endoscope. If you find that the guide tube has loosened, repair welding or replace the liner directly, don't hesitate.
3. Installation stress or displacement exceeds limit
directly buried expansion joint、Compound hinge transverse expansion jointThese products are mainly used to absorb displacement in a specific direction. If the cold tightening is not in place during pipeline installation or the supports and hangers fail, it will cause the compensator to bear additional stresses outside the design range. At this time, the abnormal noise is often accompanied by a "click" of metal crash, which sounds like a part being hard pulled. What to do? Recalculate the pipeline compensation amount and adjust the tie rod nut (how to adjust it, refer toHow to adjust the tie rod nut of expansion jointThat Q&A). Remember: the tie rod is not a trim piece, it is directly related to the safe life of the compensator.
4. Media Scour and Foreign Matter Stuck
Metal Corrugated Expansion Joints in Cement IndustryAndRubber PTFE compensatorWhen conveying powder or particle-containing wastewater, the hard particles get stuck in the ripple trough and produce scraping sound with the fluid movement. There are worse scenarios: foreign objects such as weld slag and flange gasket fragments enter the pipeline and get stuck inMetal hoseOrPTFE-lined hoseIn the ripples, the sound was like sandpaper grinding iron. Response: Install the filter or check the cleanliness of the previous process. Don't think that changing a new compensator can solve the problem-if you don't catch the source, it will still ring after changing it.
Finally, emphasize: Don't change parts blindly
First, collect the three information of abnormal noise type, working condition (temperature, pressure, medium) and pipeline layout diagram, and eliminate them one by one according to the above reasons. If you are unsure, report the parameters directly to an experienced expansion joint manufacturer-after allRotary compensator、Sleeve type pipe expansion jointThe debugging methods of these specialty models vary greatly. By the way, two days ago, a client asked whyNon-metallic expansion joints (fabric fiber expansion joints)After half a year, the hole was accompanied by a hissing sound. It was found that the flue gas temperature exceeded the design value of 30℃, and it was directly burned through. Therefore, selection and installation are much less worry-free than remediation after the fact. Don't wait until the "quack" sounds on the scene to be anxious. Check the working parameters in advance, which can save 80% of detours.