Do non-metallic compensators count as pipe fittings? Stop being stupid and confused
"Does your rectangular non-metallic expansion joint count as a pipe fitting? I checked according to the pipe fitting standards for a long time but couldn't find the model." This problem is actually quite typical-when many people select pipelines, they see that the nonmetallic compensator is installed in the middle of two sections of pipelines. As soon as the flange is twisted and the weld joint is dozen, it is automatically classified as "pipe fittings". But is that really the case? Let's be clear at the root.
Look at the definition first: Non-metallic compensator and pipe fittings are not the same thing at all
Non-metallic compensators, such as this site'sRectangular non-metallic expansion jointAndrubber compensator, mainly made of fabric fiber, rubber, PTFE and other non-metallic materials. Its core mission is to absorb the thermal displacement of pipelines, reduce vibration and noise-to put it bluntly, it is to serve as a "cushion" for pipeline systems. What about the pipe fittings? According to national standards, pipe fittings refer to rigid elements used to connect pipes, change direction or branch, such as elbows, tees, flanges, and reducers. Functionally, the pipe fitting is responsible for "hard connection" and the compensator is responsible for "soft compensation". Both are not on the same channel.
Then why do people still treat non-metallic compensators as pipe fittings? A common myth is the installation location: it is welded or flanged in the middle of the pipe and looks like a section of "special pipe part". However, the compensator itself does not have the function of pipeline circulation and load bearing, it is only a flexible compensation section. Think of it as in a plumbing systemjointWhile pipe fittings areSkeletal connector— Do you say joints can be considered bones?
Let the data speak: the ability of compensator, pipe fittings really can't learn
Let's take the products of this site as an example.Non-metallic expansion joints (fabric fiber expansion joints)The working temperature is often several hundred degrees, the corrosion resistance is strong, and the compensation amount is often tens or even hundreds of millimeters. However, ordinary pipe fittings (such as carbon steel elbows) are at most pressurized and guided. When encountering the stress caused by thermal expansion and contraction, it can only carry it hard-if it can't carry it, it will crack and leak. Another exampleFlue gas baffle doorThe matching non-metallic compensator specifically solves the stress concentration caused by thermal expansion of high-temperature flue gas pipeline. Can traditional pipe fittings solve this problem? Obviously not.
The compensator can absorb not only axial displacement, but also lateral and angular displacement. Like this site'sCompound hinge transverse expansion joint、Curved tube pressure balance expansion joint, are specially designed for complex displacement conditions. What about the pipe fittings? It can only provide fixed geometric connections with no displacement compensation capability. So functionally, non-metallic compensators are completely different from pipe fittings.
Standard system: each has its own "ID card"
"According to GB/T 12459 pipe fitting standard, is the non-metallic compensator missing?" In fact, nonmetallic compensators have their own exclusive standards- -JB/T 12235-2015。 This standard specifies the technical requirements, test methods and inspection rules of non-metallic expansion joints in detail. The pipe fitting standard does not cover it at all. Although it is classified as "pipe accessory" in some engineering classifications, "accessory" does not mean "pipe fitting". Pipe fittings focus on geometry and connection sealing, and compensators focus on displacement compensation performance-well water does not intrude on river water.
This site'sRubber PTFE compensatorAndPTFE compensatorIf you take the standard pipe fittings to set, the model does not match, and the parameters do not match. Why? Because the fatigue life, displacement absorption and temperature resistance grade are considered in the design of compensator, the pressure grade, wall thickness and sealing surface form are considered in the design of pipe fittings. Two sets of logic, when mixed together, will inevitably go wrong.
Conclusion: The non-metallic compensator is not a pipe fitting, so do not confuse the selection
Non-metallic compensators are not pipe fittings. It is a stand-alone element in the piping system specifically designed to compensate for displacement and dampen vibration. Next time someone asks you, just throw this sentence: "Pipe fittings are rigid connected, and compensator tubes are flexible compensated-different ways do not conspire." When selecting, do not remove the sleeve according to the parameters of pipe fittings, which is easy to cause problems. For example, if you choose the expansion joint with the pressure level of the elbow, you may ignore the displacement; Taking the temperature resistance of the tee to select a non-metallic compensator may not meet the working conditions at all. Don't believe it? Go check out this siteCorrugated expansion joint for power station industryAndMetal Corrugated Expansion Joints in Cement IndustryTheir parameter tables and fittings are completely different from the same way.
Find out the categories, and select models to reduce pits. A non-metallic compensator is a compensator. Don't stuff it in the pipe basket.