rotary to linear mechanism 1

[Clive]

I seek an alternative mechanism that will convert rotary motion into linear motion in the same way as a rotary govenor does on a steam engine.This is to control a needle valve proportional to r.p.m

 

[butelja]

One method is a hydraulic governor. The rotating shaft drives a gear pump that circulates oil. There is an orifice in the discharge line of the pump. The oil pressure upstream of the orifice will be proportional to the shaft rpm. This pressure signal can be used to control a linear hydraulic actuator on the valve. This is similar to how the governor on a steam turbine works.

 

[Clive]

Many thanks this could be the method i am looking for.

i have an electronic controller for my gas turbine that would normally control an electric fuel pump, my new engine will be propane powered and has a gas needle valve, I can link these up.

 

[butelja]

Just another thought. If you replace the fixed orifice I mentioned above with a needle valve and use a spring return actuator on your gas valve, then the needle valve will effectively become your throttle. You may also want to consider a needle valve in parallel with a fixed orifice. Without the orifice in parallel, it would tend to drive your gas valve wide open if the needle valve is closed.

 

[Clive]

My current show stopper is how to supply the necersary oil to fill a needle actuator cylinder. This system will be required to fly and take up all manner of attitudes so a conventional oil tank is out of the question. Do you have a schematic for the two previous suggestions.
Clive

 

[butelja]

A possible solution for the oil tank is to use an accumulator. This is a small pressure vessel with a piston or diaphragm that separates the liquid from a pressurized gas. It is pressurized with nitrogen, and then the oil is pumped into it. The system will then have to be bled free of air.

 

[Clive]

I had this in mind but was not sure how the back pressure of the gas/piston would be affected. Could you pass me a simple schematic of the options allready discussed, any format will do including autocad *.dxf to chl@star.sr.bham.ac.uk

Regards
clive

 

give me instructions to how to build this