Find out first: What is the difference between non-metallic compensator and metal compensator?
Many customers ask as soon as they come up, "Isn't the compensator just a metal bellows?" Alas, this misunderstanding is big. The materials used in non-metallic compensators (also called non-metallic expansion joints and fabric fiber expansion joints) are glass fiber, silicone cloth and polytetrafluoroethylene, which are not deformed by metal corrugations at all. Its core ability is to absorb the thermal displacement of the pipeline in all directions-axial, transverse and angular directions, and the thrust on the pipeline is particularly small. Think about it. In the big flue of the power plant, when the temperature rises, the iron pipe can jump for several centimeters. If the metal bellows is carried hard, the thrust is so strong that the bracket can be crooked. What about non-metal? Soft connection with almost zero force. So,What does a nonmetallic compensator do?The first is "large displacement, low thrust".
High temperature resistance and corrosion resistance are its special skills
Commonly used non-metallic materials, silicone cloth can withstand more than 300℃, and polytetrafluoroethylene (that is, the PTFE-lined and rubber PTFE compensator in our station) is stable to strong acid, strong alkali and desulfurization flue gas. Look at the pipe connected behind the desulfurization flue gas baffle door. The medium is wet and acid, and the metal bellows will be corroded in less than a few months. Replace withNon-metallic expansion joint (fabric fiber expansion joint)For three or five years. And it is not afraid of dust accumulation, rectangular pipes (likeRectangular non-metallic expansion joint) Especially easy to use. Two days ago, I met a customer from a cement factory, saying that the high-temperature air duct at the end of their kiln had been leaking ash with metal before, and it was directly cured with non-metal. Therefore, the second function: in the harsh working conditions of high temperature, corrosion and dust, non-metal is the only reliable choice.
Reduce vibration and noise, and solve the sealing problem by the way
When such equipment as fans and compressors is turned on, the pipes shake like sieves. Metal compensators can reduce vibration, but they also pose a risk of metal fatigue. Because the material of non-metallic compensator is soft, it is born to absorb vibration, and it can eat a lot of noise. And its sealing performance is critical-a lot of flapper doors (Round flapper door、Double-sealed single-axis circular baffle door) Soft connections are required both front and back to ensure zero leakage. When installing with other products in the station (such asElectric plug-in insulation door) cooperation, the non-metallic section just plays the role of flexible transition. And guess what? Some customers specifically requested a non-metallic compensator insteadrubber compensatorBecause the upper limit of pressure and temperature resistance of fabric fibers is much higher than that of pure rubber. The third function: vibration and noise reduction plus high-grade sealing, three birds with one stone.
Actual scene: power station, cement, desulfurization, none of them can run away
It's useless to just talk about theory. Let's talk about real working conditions. Power station industry: The flue from the boiler outlet to the dust collector, with large temperature change and large pipe section, can only be usedRectangular non-metallic expansion joint。 Cement industry: raw material mill, kiln tail high temperature fan, airflow contains dust, useNon-metallic expansion joint (fabric fiber expansion joint)Most stable. Desulfurization system: inlet and outlet of absorption tower, the medium is gypsum slurry and wet flue gas, which is highly corrosive. The non-metal compensator is equipped with PTFE lining, and its life is three times longer than that of metal. Look at the product list in the station, "Desulfurization flue gas baffle door”、“Corrugated expansion joint for power station industry”、“Metal Corrugated Expansion Joints in Cement Industry"There are all, but the non-metallic models that truly withstand corrosion and high temperature are the key connection points of these systems. Article 4 Function: Specializing in the treatment of stubborn diseases in the industry of high temperature, corrosion and large displacement.
Do not step on pits when selecting models: pay attention to temperature, pressure and displacement
Many customers choose non-metal according to the parameters of metal compensator, and the result is broken in a few months. The weakness of non-metallic compensator is that the pressure bearing capacity is not as good as that of metal, and it is generally only used in flue duct systems with low pressure (below 0.1MPa). The temperature should be distinguished between the medium temperature and the surface temperature. The fabric fiber can carry it to 1000℃, but the lining insulation layer should be calculated well. In terms of displacement, non-metals can be very large (such as 100mm in the axial direction and 50mm in the horizontal direction), but the flange connection and guide tube need to be designed well-you refer to the question and answer on "Specific Function of Expansion Joint Guide Tube" in the station, and non-metals also have to be equipped with guide tubes, otherwise the airflow will directly scour the fabric lining and wear it out quickly. Also, when installing, do not tighten the fastening bolts too tightly to prevent crushing the non-metallic sealing surface. Remember one thing: non-metallic compensators are designed according to the idea of "soft connection", so don't let it suffer. Fifth Function Tip: Choose the right one, it is more durable than metal.