Slotted holes for sliding saddle

[ercegs]

Does anyone know how to determine the length of slotted holes? Are there any standards for them or how? I need slotted holes for sliding saddle support of heat exchangers, and I don't know what length to use. I allways draw it approximately but I need it to be correct?

Thanks

 

[gr2vessels]

Calculate the expected thermal expansion, multiplying the length between saddles with the coeff. of thermal expansion for the given max temperature and multiply with the maximum operating temperature differential. Add some margin and that should be the distance between the centres on the slotted hole. Typically, that distance is a lot smaller than the bolt nominal diameter, so select the distance between centres as the bolt diameter or more generous, the width of the slot. There you go.
Cheers,
gr2vessels

 

[ercegs]

Thanks. If I understood You well, when I have bolt hole diameter e.g. 30mm,then the distance beetwen centres on the slotted hole should be 30mm? So the length of hole would be 60mm? Is that correct?

Thanks once again.

 

[gr2vessels]

Yes, it is correct.
gr2vessels