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torque value 3
- Thread starter jacbp
- Start date
You did not provide enough information to do a complete analysis. You did not even provide enough information to do a simplified analysis. What is the thread pitch? What lubricant will be used? What is the bolt threaded into? What is the pressure on this area? What mechanical loads are present? Are you an engineer or a student?
Johnny Pellin
Johnny Pellin
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2
- #3
Here is a chart, but will it be sufficient for your application?
Ted
Ted
- Thread starter
- #4
we are manufacturing transformers. i am using 10mm 4.8 strength nuts and bolts to seal the cover plate and transformer tank flange.6mm thick cork sheet is used between cover plate and tank flange. after that we pressurized this by using transformer oil.the pressure applied in cover plate and flange level is is 0.25 bar. Also there are two lifting hooks welded on top the cover plate and use to lift the transformer. so i need to tight the bolts to avoid any leakages. for that please send me any formula to calculate required torque to tight the cover plate and tank flange. if you need drawing of flange and cover plate i can attached them. cover plate thickness is 5mm. and flange thickness is 6mm.
Are those lifting lugs really welded on the coverplate? So you'll lift the transformator through the lugs, the 5mm plate and some 10 mm bolts?
And a 6mm cork gasket needs to seal the oil tank?
I'd change the design, and buy a John Bickford book about gasketed joints, and some design guides as well as this sounds like a really bad idea.
just my 0.02$ worth...
And a 6mm cork gasket needs to seal the oil tank?
I'd change the design, and buy a John Bickford book about gasketed joints, and some design guides as well as this sounds like a really bad idea.
just my 0.02$ worth...
I agree with kingnero. This sounds like a really bad design.
The level of help that you require is far beyond what you can reasonably expect to achieve for free in an internet tips forum.
You need to hire a qualified mechanical engineer.
The level of help that you require is far beyond what you can reasonably expect to achieve for free in an internet tips forum.
You need to hire a qualified mechanical engineer.
Kingnero.... Your .02$ worth, is worth at least 10 bucks. This OP just proves that we walk around and under way to many things designed and manufactured by people who don’t have the vaguest idea of what their real product (except by name) or real problem is; or even how to explain it in enough detail to illicit a meaningful answer.
I think the OP’er should get some local engineering and design help with his problem, from his boss or a senior engineer, rather than coming here for a supposed simple formula, all rolled into one, to solve his problem. If for not other reason than to keep his company out of legal trouble, but more importantly so as not to hurt other unsuspecting people or electric rate payers who buy their equipment. This is not a particularly difficult design problem, but the OP’er doesn’t even show the basic engineering understanding to break it down into its parts. As he describes it, it sounds like a bad design to me too.
I think the OP’er should get some local engineering and design help with his problem, from his boss or a senior engineer, rather than coming here for a supposed simple formula, all rolled into one, to solve his problem. If for not other reason than to keep his company out of legal trouble, but more importantly so as not to hurt other unsuspecting people or electric rate payers who buy their equipment. This is not a particularly difficult design problem, but the OP’er doesn’t even show the basic engineering understanding to break it down into its parts. As he describes it, it sounds like a bad design to me too.
Similar to what others have said, my opinion is asking a compressed gasketed joint to serve a structural function is probably asking for trouble. One way around it might be to have the cover and flanges stout enough, and use an o-ring so the joint would be drawn up hard, metal-to-metal. Or replace some of the cover bolts with lifting eye bolts.
It looks like for transformers above a certain size the lifting function is kept separate from the cover. I have no clue if that might even be driven by some code.
It looks like for transformers above a certain size the lifting function is kept separate from the cover. I have no clue if that might even be driven by some code.
Cork gasket? Blech! I didn't think that anyone used cork anymore.
Anyhow, how much does this thing weigh? Can you give some dimensions? You'll want to do a proper analysis to make sure that something doesn't break and kill someone.
Usually you'll want to crank the bolts down to 75% yield or something along those lines.
As was said, asking a gasketed joint to do yeoman's work is probably not a good idea, unless you've specifically designed it to do so.
//signed//
Christopher K. Hubley
Mechanical Engineer
Sunpower Incorporated
Athens, Ohio
Anyhow, how much does this thing weigh? Can you give some dimensions? You'll want to do a proper analysis to make sure that something doesn't break and kill someone.
Usually you'll want to crank the bolts down to 75% yield or something along those lines.
As was said, asking a gasketed joint to do yeoman's work is probably not a good idea, unless you've specifically designed it to do so.
//signed//
Christopher K. Hubley
Mechanical Engineer
Sunpower Incorporated
Athens, Ohio
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- #12
Transformers with bolted top covers usually incorporate lifting points to lift the cover off the tank. There are (should!) be separate lifting points for the main tank. From experience there are normally two on diagonally opposite corners for smaller units up to say 6 tonnes with four fitted on larger types, and jacking / skate locations for the big ones. I've twice stopped riggers from lifting a transformer using the cover. I suspect the result would have been messy.
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If we learn from our mistakes I'm getting a great education!
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If we learn from our mistakes I'm getting a great education!
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