Help with designing thruster for rov.

[eliotegli77]

Hi there,
I plan to build a ROV, and am currently looking at different methods of propulsion. I do not wish to use `o` rings or seals and have considered magnetic coupling for the propellor to the electric motor, or even hydraulics. Cost is an issue. Would appreciate any advice on building a ROV. Plan to build a ROV to use in depths of around 100m. Thanks.

 

[my_wan]

A magnetic coupling sounds like the best way to avoid orings but it should not be a separate magnetic coupling than the one that already exist between the motor and its' rotor. Have you ever seen how an small aquarium water pump works?

 

[eliotegli77]

thanks for reply, no have not seen how one works. Was thinking that the magnetic coupling may be the best option.

 

[Danger]

This came up a long time ago, with quite a long series of responses. One suggestion was to not bother sealing the motor and just flood it with mineral oil to keep water out. I can't remember the exact details, but a forum search should bring it up for you.

 

[eliotegli77]

Thanks danger, will do a search and see what comes up. Have heard of that before, sounds like a good option perhaps easier than the magnetic coupling.

 

[FredGarvin]

I guess I don't understand the aversion to using o-rings. They are easy and cheap. They will handle pretty much any pressure gradient you throw at them and have a wide variety of materials to suit any application.

 

[brewnog]

And there's plenty of bellows/labyrinth glands which will do the job wonderfully too...

 

[FredGarvin]

A labby is probably not the best for this application. They have to be constantly rotating in order to seal. If I am not correct, there are going to be times where these thrusters would not be moving. Plus to get a complete seal it would have to have a buffer supply of air from somewhere.

 

[mo3eed]

please i want to hlep in designing thruster for ROV

 

[ROV freek]

Hi

Use lip seals and fill the whole thing with oil.
Silicone oil is best, but almost any thin floating oil can be used.
+0,3- +0,5 bar compensation on the oil is recommended.
Works fine, and no limits regarding ocean depth.