|
Hi Lawrie,
from what I can understand of the explanation on
oil compensating a motor on the ROV site is this....
If you have a motor with half pie reasonable seals,
you just fill it with a suitable low viscosity oil.
You have a drain nipple in to the bottom of the
motor casing & a nipple for attachment of a hose
on the top of the casing. You attach a tube from
the top nipple to a bellows or as they suggested
something like the bladder in a football. This is
filled with oil & pressurized to about 15 psi so there
is always an external pressure of the motor
oil over the internal pressure of the sea or lake water of
15 psi no matter what depth you are at. You can use
the one bladder for all your motors.
The other option they mentioned was in the case
where the motor might not be designed for underwater
applications & the seal not so good. In this
case you can make an enclosure, put a suitable shaft seal
in the enclosure & do the same as the first
option with the nipples tube & bladder but on the enclosure
not the motor. The motor inside would need to be
filled with oil & have an opening in it. There shouldn't be
any air in these systems.
The idea of the seals back to back seems to be an
additional option as a safe guard.
I bought a couple of trawling motors that I
couldn't easily change the seals on so will be trying the oil
bladder method & if I'm going through too much
oil then maybe air compensation or buying some better motors.
Regards Alan
----- Original Message -----
|