developing a inner pipes inspection robot

[Oliveros]

Users,

i'm developing a inner pipes inspection robot, it will work inside 200 mm diameter pipes, and those pipes are under sea water, at 30 m depth. it must be four wheel drive, but i need design the water proof system. All the motors will be inside the case, and the controls and electronics will be on surface. here goes the questions:

1. how can i design the water proof system?, how i connect the wheels to the shaft in a very reliable water proof manner?

 

[patprimmer]

Can you use a magnetic drive, so there is no hole to seal

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Oliveros]

pat,

thanks, your answer in eng-tips is very helpful.
but i'm stll have some question, where can i learn about magnetic drive?. is first time that i hear this kind of drives. if you can help me.


regards

 

[patprimmer]

Put simply, there is a driven flange on the inside of the hull, very close to the hull, with two magnets inserted into it with say the north poles close to the hull surface and 180 degrees apart.

The wheel is mounted on a device completely outside the hull and has a flange with two magnets with the south poles very close to the hull surface, and 180 deg apart.

This system is of course totally waterproof, but is limited in the amount of torque it can transmit, and is very sensitive to the distance between the flanges.

The only applications in which I have seen it used are laboratrory dyeing machines to drive an agetator for the heat transfer medium bath, and for stirers in laboratory beakers.

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[amorrison]

In some situations the motor is flooded with a suitable liquid to react to the external water pressure.
Should be environmentaly friendly liquid in case of leakage.
I am aware of a hydraulic drive system that uses peanut oil so as not to "contaminate" anything.

 

[amorrison]

Using "oil filled motor" -transformer* -mounts -sump -sewage -thermally -little –giant
in Google I only got these. I thought they would be much more common!

http://www.empiremagnetics.com/articles/deep_sea.htm

http://www.empiremagnetics.com/prod_wat/prod_wat.htm

http://www.vibolucht.nl/at_prod_offshore.html

Good luck

 

[Oliveros]

thanks about the tips, but remember, the motor that i asking about are 'toy motors' 12V, very small, to a robot of 10 inches.

oliveros