Flange leakage

[Giray Veli]

Hi everyone, we have a hidrocloric acid furnace, this furnace has 3 part and every part connected each other with flanges. We are running that furnace for 15 months and furnace temperature between 250-400 C(varies according to load) this furnace has leakage from the flanges connections. When we tighten the bolts ıt ıs not stopping, there is no any crack or etc. I am sure ıt ıs tighten problem because last week when ı tighten the bolts leakage has stoppen but we had a shot down and restart the furnace after that it started the leak. For tightining if you have any idea please let me know.

 

[r6155]

More data: bolt material, diameter, flange type, gasket type / material, pressure, ....... etc.

 

[LittleInch]

Agree. I'm thinking these are large diameter low pressure flanges with many bolts. These types of flanges are notoriously difficult to seal as very slightly distortions can easily occur.

Tightening bolts is a poor way to get accurate bolt force. You might need to use hydraulic pensioners instead.

Having high temperatures is difficult so you might need things like belville washers to maintain more fixed force over your temperature range.

But without more details, it's all very vague...

 

[Giray Veli]

More data: bolt material, diameter, flange type, gasket type / material, pressure, ....... etc.

Bolts are carbon steel and M20, this purple area has leakage, gaskets are viton and furnace steam pressure is 5 barg.

 

[Giray Veli]

Agree. I'm thinking these are large diameter low pressure flanges with many bolts. These types of flanges are notoriously difficult to seal as very slightly distortions can easily occur.

Tightening bolts is a poor way to get accurate bolt force. You might need to use hydraulic pensioners instead.

Having high temperatures is difficult so you might need things like belville washers to maintain more fixed force over your temperature range.

But without more details, it's al

There are spring bolts on these furnaces other connections. The vendor send us the dimensıons of tightening but for that bolts which has leakage no information, no dimensions thats why we are facing with that problem.

 

[r6155]

1) The tightening sequence of the bolts must be controlled.
2) For bolts L>5d, the required elongation must be measured (torque value is not applied here)
3) Carbon steel bolt is undefined. Need exact material stamped in the bolt and nut
See ASME PCC-1

Also the gasket may be damaged.

 

[Giray Veli]

Thanks for your kindly replies, we have solved the problem. The problem ıs our return line valve was broken and we didn't know that today we observed it and when we change the valve the problem solved.