Flange contact surface sealing problem
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There is a 1200mm pipeline in our factory. The valve and the butt flange surface are not parallel. It cannot be sealed with ordinary asbestos pads. What kind of sealing is better? Please help.
You can make it yourself. It depends on the pressure. If it is less than 2.5, use annealed aluminum plate to wrap asbestos nickel wire filler to make a pad! Theoretically yes!
Pipe specs? How big is the non-parallelism?
The pipe is 1200mm, and the angle between the flange surfaces is about 5°.
It's not easy to handle. I suggest the poster cut off the flange and re-weld it.
It seems that mechanical methods (flange closer and flange adjustment tools) are more difficult to solve.
What's the pressure in the pipeline? Is the medium gas or liquid? If the pipeline pressure is high and the medium is gas, it is safer and safer to cut off the flange and re-weld it. If the pressure is low and the medium is better sealed, you can use a gasket with a softer material to compensate, and it should be barely usable.
Add a section, a expansion joint for steam pipes!
I've seen sealing methods like this. First make a ring of the same size as the sealing surface from a thin plate, and then wrap the ring with Teflon rope (diameter 3-6). The coating process must be done carefully. It is best to wrap 2 layers. Then wrap more targeted (slightly denser) windings at the angles. This pad can make up for the trouble of non-parallel flanges during installation. But suitable for low pressure pipelines (gas). Hope it helps.
Weld again. If the diameter of the pipe is smaller, you can also bend it.
Suggestions: 1. Cut off the flange, fix the flange and the valve before welding. 2. If the flange and the valve can be separated by a certain distance, make a metal pad with the opposite slope to the flange, and add asbestos pads on both sides for sealing.
If the medium used is water, it is recommended to use asbestos boards to make inclined gaskets.
1200mm pipeline? It should probably be buried. For safety reasons it is best to cut it off and redo it. Connect the flange first and then weld it.
An over-the-top steel pad can be made. The two surfaces should not be parallel machined so that the inclination angle of the flange is basically the same. Putting sealing gaskets on both sides should be able to solve the problem.
If the angle is not too big, you can try expanded PTFE. The operation is relatively simple.
Calculated based on the diameter of 1200 and the angle of 5 degrees, the maximum gap is 104mm. The most effective method is to cut the original pipe at a certain distance away from the flange, and weld a Xiami elbow section in the middle. The angle of this Xiami elbow is 5 degrees. The length is accurately determined by on-site measurement.
Learn again* :handshake :victory:
1. Cut it and prepare it again. 2. If the fire cannot be used or replacement is inconvenient, add a slanted orifice plate for installation (it is too big and the tofu plate will become meat! )