Conduit around cylindrical structures

[dmxrr]

Hi all,

Thinking of running some 25mm galv around the inner skin of our large silo's for lighting. 

Problem is getting the bends spot on because I've got to make it up all outside and cart it in.

It requires lots of little small deg bends to get the arc right.

Apart from the usual way of eyeing it up, Is there a mathematical way of calculating the spacing and degree of the little bends? 

Cheers.

 

[Rob_the_rich]

The circumference of the circle is pi (3.141....) x diameter.

decide how many bends you want per length, to work out the distance between bends

divide the circumference by the distance between bends = number of bends

divide 360 by the number of bends to get the angle of each bend

if you can, chose a distance between bends so that you start bending a length of conduit half that distance from the end, so that when joined, the joint is in the middle of a standard sized straight bit. If that makes sense.

 

[Essex1]

We do a lot of these in railway arches. Forget maths. Just need an eye and bend each 'kink' a lot lot less than you think. 

 

[Evans Electric]

And may the Lord have mercy on your soul .

I think I'd be looking at Pyro or similar TBH.

This is a wind up ....25mm steel conduit curving round a silo.!

 

[Andy™]

get a tube roller

 

[kerching]

As an apprentice i ran the conduit around a spiral stone staircas. Up into a church bell tower.......think bending a circle BUT in three dimensions.      Hilmor bender?.......nope!    Piece of 4x3 with a hole in it!

just reeling at the thought of it

 

[Essex1]

And may the Lord have mercy on your soul .

I think I'd be looking at Pyro or similar TBH.

This is a wind up ....25mm steel conduit curving round a silo.!

Can be done easily. A man of your caliber should have no problem.  :B

 

[dmxrr]

This is a wind up ....25mm steel conduit curving round a silo.!

Nope, I've done it before. Just a bit tricky this one as its all got to be bent and threaded on the floor outside.  

 

[Evans Electric]

Why do you need 25mm ?    Thats a lot of lighting  I have to say.   What is gained by using 25mm steel conduit. I ask?

It reminds me of a ridiculous job we had to some years ago .    We used to do a lot of work at local hospitals and one was to rewire a remote admin building which was actually a 5 bed 1930s house within the hospital grounds , now used as offices.

Trouble was , the NHS standard specification didn't cover any work done in T&E  (  6242Y  etc)  and it was obviously beyond the realms of possibility to ammend that so.........  the house had to have the rubber T&E removed and  B/E Steel conduit installed flush ,in accordance with their standard Spec.  

 

[Tony S]

Just an idea. Make a cardboard/hardboard template of the curve, you can then work to it outside. A wooden bending block is better than a Hilmore for long curves.

 

[kerching]

I Was going to suggest drawing a chalk circle on the floor as a guide line. Just make sure it is smaller than the diameter of the Silo by 2x the spacer saddle base if you are using them

 

[Tony S]

The Circle of Chalk by Li Xingdao (14c)

 

[Rob_the_rich]

chalk lines in a farm? you'll have all the chickens hypnotised.

 

[Evans Electric]

You could make your job even harder by doing it in steel trunking ..................make thousands of saw cuts and then push it into place . 

 

[binky]

armoured copex?

 

[kerching]

Why not do it in stainless steel conduit for a laugh?

mind you, when silo is full will you even see the lights?.....i know little of the innards of a silo! The last one i saw contained an ICBM

 

[Blue Duck]

what is going in the silo? does it need to be EX? 

If it's has to be EX you can get EX rated flexible conduit and glands.

linky

 

[Blue Duck]

Why not do it in stainless steel conduit for a laugh?

mind you, when silo is full will you even see the lights?.....i know little of the innards of a silo! The last one i saw contained an ICBM

are they the silo's near the end of the runway at Kerch towers near the horse wash? 

:innocent

 

[dmxrr]

Why not do it in stainless steel conduit for a laugh?

mind you, when silo is full will you even see the lights?.....i know little of the innards of a silo! The last one i saw contained an ICBM

They are large, approx 100m circumference and have a bund wall which is where the lighting will be going to allow for maintenance work on internal pipework.

No need to be Ex rated and I still prefer rigid conduit for these applications rather than copex personally.

 

[kerching]

are they the silo's near the end of the runway at Kerch towers near the horse wash? 

:innocent

We got rid of the ICBM silos after the "uprising' of 1999...staff thought that since we were reaching the millenium they should strt to be paid! As if!