1. Why does a product have so many names? — — Origin of the other name of rectangular metal expansion joint
When you tell the purchaser, "I want a rectangular metal expansion joint", he looks confused; You switch to "Metal Rectangular Compensator", and he nods immediately. The same thing, called "Corrugated Expansion Joint" on the drawing, "Stainless Steel Compensator" on the spot, became "Metal Soft Connection" in the old mage's mouth.Rectangular metal expansion jointEnough to compile a little dictionary. Why?
Structural characteristicsAndIndustry habits。 From the structural point of view, its core is metal bellows, so many people directly call it "corrugated expansion joint". From the shape, the rectangular section is different from the circular section, so it is called "rectangular compensator". From the functional point of view, it absorbs thermal displacement, reduces vibration and noise, so "compensator" has become a common name. Coupled with the customized names of different industries-power plants are called "flue expansion joints" and cement plants are called "air duct compensators". Each circle has its own name.
But don't underestimate this "address problem". Two days ago, there was a dust removal project, and the customer specified a "non-metallic rectangular compensator". As a result, the on-site temperature was 350℃, and the non-metallic fabric couldn't bear it at all.Metal rectangular expansion jointTo solve the problem. The name is wrong, the equipment is scrapped, and the construction period is delayed. The essence of figuring out the nickname is to figure out the product boundary.
II. Rectangular Metal Expansion Joint vs Non-Metal Rectangular Compensator: Material and Structural Differences Behind the Alias
These two names are often mixed, but they are actually completely different products. It is clearly written in the product library of our website:Metal rectangular expansion joint(corresponding to the "Metal Rectangular Expansion Joint" of this site) andRectangular non-metallic expansion joint(Corresponding to the "rectangular non-metallic expansion joint" of this site). They are all rectangular in shape, but the material determines the performance boundaries.
- Metal rectangular expansion joint: The main body is stainless steel corrugated pipe, which is resistant to high temperature (600℃ +) and high pressure (up to several MPa), and absorbs displacement by corrugation deformation. It is commonly found in boiler flue of power station, cement kiln tail and hot air duct of iron and steel plant.
- Non-metallic rectangular compensator: The main body is fabric fiber + rubber/silicone layer, and the temperature resistance is usually ≤350 ℃, but the compensation is large, the cost is low and the installation is convenient. It is suitable for low-temperature flue gas, dust removal pipeline, fan inlet and outlet.
Some suppliers blow non-metals into metallic alternatives in order to save costs. But to be honest: under the working condition of the main flue of the power plant above 400℃, non-metals will embrittle and crack in one month. If you spend 30,000 on non-metals, why don't you spend 50,000 on themMetal rectangular expansion jointIn ten years. Not called mixed, the selection follows the deviation.
Third, the wrong names in power plants and cement plants
Anyone who actually ran through the scene knows that the names coming out of the mouths of workers and technicians may be far from those written in the instructions.
Power Plant Scenario:Rectangular expansion joint of desulfurization system, they call "flue gas baffle door expansion joint" or "desulfurization flue gas compensator". But technically speaking,Flue gas baffle door(This station has "flue gas baffle door" and "desulfurization flue gas baffle door") is a device that cuts off the airflow, not a compensator. In order to save trouble, the workers mixed the baffle door with the expansion joint. If you don't check the model when purchasing, buy a baffle door and install it as a compensator, and the thermal expansion and contraction of the pipeline will directly be damaged.
Cement Plant Scene:The rectangular pipes at the head and tail of the kiln are "non-metallic expansion joints" when the technician opens his mouth, because traditionally, non-metals are mostly used in the low-temperature section of cement plants. However, that high temperature section (preheater outlet, decomposition furnace inlet) must still be useMetal rectangular expansion joint。 I have seen a case in which a cement factory wrote "metal rectangular compensator" as "metal corrugated expansion joint in cement industry" (there are corresponding products on this site). As a result, it was found to be round when it arrived, because the purchase only read the words "metal corrugated expansion joint" and didn't pay attention to "rectangular".
Therefore, it is also called a net, and you can't get out if you fall into it. The best way to do this is:Fix products with three labels of "Material + Shape + Function"。 For example, "stainless steel rectangular corrugated compensator", you can tell that it is metal, rectangular and used for compensation.
4. Only by buying the right name can you use the right product: case of wrong selection caused by confusion of alias
For the desulfurization project of an iron and steel plant, the bidding list wrote "8 nonmetallic compensators". After installation, the temperature was found to be 380℃. The upper limit of the working temperature of the non-metallic expansion joint is usually ≤350℃. As a result, the fabric layer is burned through and the smoke leaks after two months of operation. Later switched toRectangular metal expansion joint(This site "Metal Rectangular Expansion Joint"), problem solved. Reason: Party A's engineers regard "non-metal" as synonymous with "metal", thinking that all rectangular compensators are the same.
A waste incineration plant, the purchase order writes "rectangular expansion joint", and the supplier sends itRectangular non-metallic expansion joint。 However, what is needed on site is corrosion-resistant metal material, because the waste incineration flue gas contains acidic gas. Non-metallic silicone skin has limited ability to resist acids and alkali, and corrosion and perforation occurs in half a year. Final reprocurementMetal rectangular expansion joint, lined with PTFE (this site has a similar idea of "lined with PTFE metal hose").
What do these two cases illustrate?The name itself is not right or wrong, but the performance parameter that corresponds to the wrong is a disaster.When you hear "rectangular compensator", you must ask: "Metal or non-metal? What is the temperature resistance? What is the pressure?" The more vague the nickname, the more you have to speak with the parameters.
5. One diagram to clarify the alias system of rectangular metal expansion joint
Although I can't post a picture in the article, I can draw a structure diagram for you in words:
Compensator/Expansion Joint(Both are common, and Article 15 of Q&A on this site has a clear explanation)
Divide down by shape:Circular compensator(A large number of products in this site such as "Universal Corrugated Expansion Joint") andRectangular compensator(Subject of this article)
Further down by the material:Metal rectangular expansion joint(stainless steel corrugated) andNon-metallic rectangular compensator(Fabric Fiber)
Further down by industry/application:Corrugated expansion joint for power station industry、Metal Corrugated Expansion Joints in Cement Industry、High temperature axial expansion joint、Desulfurization flue gas baffle doorEtc.
That is to say,Rectangular metal expansion jointIncluding: Rectangular Compensator, Rectangular Corrugated Expansion Joint, Rectangular Metal Bellows, Flue Expansion Joint, Air Duct Compensator, Stainless Steel Rectangular Compensator... But these names all point to the same category of products:Metallic material, rectangular section, bellows structure, for absorbing displacement。
For example, "non-metallic expansion joint" is a side-by-side brother, "circular baffle door" is a valve product of different shapes, and "large tie rod expansion joint" is a different variation of structural form. Aliases don't change the physical nature of the product, but they affect your search keywords and purchase lists.
Find out the nickname and spend less money. Next time you buy rectangular metal expansion joints, don't just look at the name. Write the material, temperature, pressure and displacement clearly, which is more useful than anything else.