What kind of gasket is suitable?
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There are two enamel reaction kettles in my workshop. All the gaskets on the kettles are made of asbestos filler and agglomerated polytetrafluoroethylene. The media in the kettle include sulfuric acid, 120# solvent oil, organic alcohol, and organic acid (weak). The current problem is that each gasket leaks badly, because the packing is elastic and will leak after a short time after tightening. At the same time, solvent oil has swelling properties, and PTFE is very thin and easy to dissolve. I plan to choose a gasket with better sealing, but I don’t know which one is suitable (currently graphite spiral wound gaskets are used in several places, and the effect is OK for the time being, but spiral wound gaskets will cause enamel damage and sulfuric acid corrosion of gaskets). The maximum temperature in the kettle is 170 degrees Celsius, and the maximum pressure is 0. 4Mpa, minimum -0. 08Mpa。 Please help me choose.
Our company has encountered this problem before. Generally, the gaskets brought by Tang glass kettle manufacturers are asbestos-coated PTFE gaskets. If the reaction pressure in the kettle is slightly higher, leakage will easily occur. We now use PTFE plate gaskets wrapped with raw material tape. Of course, the raw material tape must be wrapped a little thicker, but the use effect is very good.
What was said above is the best, but we used to use asbestos board pads wrapped with PTFE tapes and it was still good!
I think using Teflon sheets would be fine.
Use graphite. Its elastic stress is relatively large and its strength is better!
Why are the people upstairs still using asbestos gaskets? Considering the health of others, you should consider using other gaskets. The PTFE gaskets mentioned on the second floor are very good.
I remember that the upper limit of the 4F mat temperature is 180 degrees. Isn’t it also dangerous (the maximum temperature mentioned by the fan is 170 degrees)?
I have a set of various gaskets to choose from, but it cannot be uploaded in the version. I will try again in a few days.
It is recommended to use PTFE material. It should be square in size, 10X10mm in size. When installed and pressed, it will be in the shape of a flat cake. It has a certain elasticity and can be acid and alkali resistant. At the same time, one side is glued.
If the medium is sulfuric acid and organic alcohol, you can also use asbestos wrapped with PTFE gasket and wrapped with raw tape. If it is thin, it is better to use thickened type.
But the 4F gasket is easily squeezed out.
The outer ring of the graphite pad is still metal, which also faces corrosion problems. In addition, graphite has low hardness and is not durable.
Wrap asbestos board with PTFE tape, the effect should be good.
It seems that most people prefer asbestos board gaskets, but they do not know whether asbestos boards can withstand the dissolution of 120# at high temperatures.
Expanded PTFE has the characteristics of corrosion resistance, high pressure resistance, ease of use and flexibility. The temperature is -140-+280 degrees Celsius and the pressure is 5.0MPa. We now use 304+ expanded graphite spiral wound gaskets and it feels okay.
Use PTFE-filled asbestos pads or flexible graphite pads.
Thank you all, I decided to try using asbestos board wrapped with PTFE first.
There is a kind of PTFE-filled asbestos sealing gasket that is very useful. You might as well use it.
What we commonly use is PTFE + raw material tape, and the effect is good.