Step 1: Find out what fairy your flue expansion joint is
Don't rush through the table, you have to ask yourself a question first: Is this thing metal or non-metal? Is it round or rectangular?
Why should we distinguish it clearly? Because weight algorithms are completely different things.Metal expansion joint(For example, the one in our stationUniversal corrugated expansion joint、High temperature axial expansion joint) The main body is stainless steel or carbon steel bellows, which has high density and mainly relies on steel for weight. WhileNon-metallic expansion joint (fabric fiber expansion joint)Inside, it is fiber cloth, silicone cloth and insulation cotton, which is much lighter, and the weight is largely on the flange and frame.
Shape doesn't escape either. The circular diameter is small and the wall is thin, so it can be calculated as a cylindrical volume; What about the rectangular ones? With large area and long side length, the amount of section steel of flange frame doubles, and the weight naturally rises. It would be a joke if you put the circle formula into a rectangle.
Step 2: Find out several 'life gates' that affect weight
The variety is settled, and then the following four parameters are held down, and none of them can be missed:
- Diameter/Section Dimensions: Look at DN (nominal diameter) for circles, and look at length × width for rectangles. This directly determines the deployment area of the bellows or skin.
- wavenumber: The number of ripples. The more wavenumber, the longer the bellows and the weight increases linearly. Remember, it's not the more the better, just enough.
- wall thickness: For every 0.5mm increase in the wall thickness of the bellows, the weight difference can be 10% ~15%. Especially in high-pressure occasions, when the wall thickness increases, the weight soars.
- Flange Material: Carbon steel flanges (Q235) and stainless steel flanges (304/316) are about the same density, but often have different thicknesses. Also, the flanges of non-metallic expansion joints are often welded with angle steel or channel steel, and you have to calculate the weight of the section steel.
For example, two days ago a customer askedCorrugated expansion joint for power station industryFor the weight of DN400, I asked him to report the wave number and wall thickness. He said, "The wave number is 8, and the wall thickness is 1.2mm", which is only 28 kilograms. Later, he changed his mouth and said that it actually needed 32 waves, the wall thickness was 2mm, and the weight was directly turned to 85kg. Look, how much difference?
Step 3: Step-by-Step Teaches You to Estimate Weight – Two Ways
Okay, the parameters are all set, let's get serious. Two paths, you choose:
Method 1: Check the experience table
We have a copy in our stationMetal expansion joint weight tableThe weights of common specifications are listed according to DN, wave number and wall thickness. Such asUniversal corrugated expansion jointDN100, 4 waves, 1.0mm wall thickness, the table says about 3.5kg. You look for your own parameters, and it is almost inseparable.
Experience tables usually give data according to standard wavenumbers (such as 4 waves and 8 waves). If your wavenumber is non-standard, you have to convert it proportionally. For example, 8 waves inside and outside are 7 kilograms, and you want 12 waves, then 7× (12/8) =10.5 kilograms. Don't just copy it silly.
Method 2: Simple formula estimation
Don't want to look up the table? That's okay. Here's a fool's formula:
Weight of circular metal expansion joint ≈ 3.14× diameter (mm) × bellows length (mm) × wall thickness (mm) ×7.85×1.1(7.85 is the steel density and 1.1 is the flange and end tube allowance).
For example, DN400, wall thickness 1.5mm, bellows length 300mm, calculated: 3.14×400×300×1.5×7.85×1.1 ≈ 4.88×10⁶ grams, about 4.88 kilograms? Wait, this unit is not right! Note that the diameter and length are in mm, which is calculated as grams. Divide by 1000 to get kilograms. The above example works out to be 4.88 kilograms? Wrong, the actual DN400 is at least a few tens of kilos. Because in the formula, the diameter is 400mm, the length of the bellows is 300mm, the volume = π ×400×300×1.5 ≈ 565,200 cubic millimeters =0.565 cubic decimeters, multiply by the density of 7.85 to get 4.44 kg, and add the flange balance to about 4.88 kg. However, the actual length of DN400 bellows is more than 300mm, and the wave number is large. The actual unfolded length of bellows is wave pitch × wave number. Generally, if DN400 has 8 waves, the wave pitch is about 50mm and the length is 400mm, which is calculated to be about 6.5kg. Plus the flange and end pipe, the total weight is about 15~20kg. This formula only counts the bellows body, you remember to add the flange weight (check the flange standard).
Tips: Think manual is troublesome? Go straight through ourMetal expansion joint weight tableWorry-free.
ForNon-metallic expansion joint, the weight is concentrated on the frame and flange. When estimating, calculate the perimeter of the rectangle, multiply it by the meter weight of the frame section steel (for example, angle steel 40×40×4, the meter weight is about 2.42kg/m), add the skin (very light, ignore or according to the area ×0.5kg/m²), and finally add the sealing gasket. The formula is simple:Weight of non-metallic expansion joint ≈ total length of frame section steel × meter weight of section steel + flange bolt weight + skin weight。
Step 4: Don't be in a hurry to place an order after getting the weight
Weight figured out, then what? Direct to Purchase? Wait! You have to think about three things:
- Transport: Can overweight trucks be pulled? Such asLarge diameter thick wall expansion jointEasy hundreds of kilograms, have to use forklift or crane to load and unload, the freight is also expensive.
- hoist: Is there a hoisting point on site? Your choiceCompound hinge transverse expansion jointOrStraight pipe pressure balanced expansion jointThe structure is complicated, and the center of gravity may not be in the center. Be careful not to break the bellows when hoisting.
- Pipe support: Can the pipe support bear this weight? EspeciallyNon-metallic expansion jointAlthough the body is light, the support points are strengthened after adding flanges and frames. Otherwise, the pipe sinks, the expansion joint is deformed under force, and the service life is shortened.
Don't laugh, somebody really bought itSleeve type pipe expansion jointWhen it was transported to the scene, it was found that the crane was out of reach, and it was temporarily paid to rent a big crane. So weight isn't just a number, it's a cost.
Step 5: Take a seat with our products
In the last step, compare the calculated weight with the products in our station, and feel more bottom.
- Universal corrugated expansion joint: DN50~ DN600, wall thickness 0.8~2.0mm, weight range from 1kg to 150kg. Small diameter is light, and large diameter is heavier with flanges.
- Metal rectangular expansion joint: Rectangular section, side length several hundred millimeters to several meters, frame of channel steel or I-beam, the weight is usually measured in hundreds of kilograms.
- Non-metallic expansion joint (fabric fiber expansion joint): Same diameter, only 1/3 to 1/5 of the weight of metal. For example, for a 1000×500 rectangle, it may cost 150kg for metal and 40kg for non-metal. However, note that the pressure and temperature resistance of non-metals are limited.
- High temperature axial expansion joint: It is used for high-temperature steam or flue gas, with thicker wall thickness and more wavenumber, and its weight is 30% ~50% heavier than that of ordinary type.
- Metal Corrugated Expansion Joints in Cement Industry: Often bring guide tubes and liners, and the weight is added to the next layer.
You asked if there is a universal weight scale? Yes, ourMetal expansion joint weight tableMost of the common specifications are sorted out in. But remember, the final weight is subject to the actual drawings, and the estimate is just to help you not step on the pit.
After all, the flue expansion joint weight is not counted correctly, and the back is full of trouble. Follow the above three steps, and think about transportation and support, and the selection will be stable. Have you learned it?