As those of you who follow this group will have read, I have been
struggling to engineer a smooth control system raising and lowering my
tilting induction furnace body - the two 3" cylinders happily slapping
it up and (destructively) down with little control.
John suggested air over oil, to avoid the conpressability of the air
on the down stoke and this is the method I've adopted which is highly
satisfactory - thanks John. I have formed an oil reservoir (slice cut
from CO2 cyclinder) with the 'up' air entering at the top, forcing oil
out of the bottom, this goes to a 'tee' with two one way valves
pointing in opposite directions. Each has a flow control valve in
series and the flows rejoin at another 'Tee' and go to the bottom half
of the two paired double acting cyclinders. This way I can control
both the raise and lower flows and hence speed of furnace movement.
During this exercise I've started using Loctite 542 hydraulic thread
sealant and I must say I am very impressed. The new 'plumbing' has 32
threaded joints each needing rotational alignment and not a single
leak (tested at 150 psi with soap solution before putting to use).
Next thing I need to tackle is a quick disconnect system for the
furnace water coolant / power hoses so I can swap between the two
furnace bodies easily. These carry water / antifreeze at 45 psi / 25
litres minute and drive power at peaks of 300 amps / 1000v at 3Khz
when at resonance. The hoses terminate in 3/4" BSP so I'm thinking of
using brass 'snap-tite' 72 hydraulic couplers with a welding 'dinse'
cable connector across them to carry the current - any comments?????
- posted 15 years ago