Simple valve gear?

[Dianne BestParticipant @diannebest69516]

I have been working with full size steam most of my life and built a 1/2 scale traction engine in 1995/96

I have recently started on a sternwheel ship model, 48" long, 10" beam, and would very much like to make it steam operated.

Because the ship is small, the goals for the engine are: small, light, low friction, reversible, easy to make (without precision machining). It would be nice (but not required) to have variable cut-off.

I have a cylinder design that is simple and eliminates packing glands but I am going in circles trying to develop a simple valve gear.

Has anybody seen a valve design on the Internet that would be low-friction and easy to build?

Thanks

Edited By Dianne Best on 06/10/2016 12:54:15

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Edited By Dianne Best on 06/10/2016 12:56:18

[Dianne BestParticipant @diannebest69516]

looking for simple, easy-to-build valve gear

[Neil WyattModerator @neilwyatt]

If you have space for two eccentrics per cylinder, it doesn't get much simpler than Stephenson's link gear.

Neil

[Dianne BestParticipant @diannebest69516]

That's a lot of parts to fit in a tight space and requires very precise fits to work well.

Back to the drawing board!

[JAParticipant @ja]

My understanding is that it does not get much nicer than Stephenson's link gear.

JA

[Martin WParticipant @martinw]

Dianne

There is a design for a small steam engine here. It uses a spool type valve gear the design of which may be suitable for your application, the reverse motion is achieved by reversing the steam flow rather than changing the phase of the valve gear which keeps things simple.

Hope this is useful

Martin W

[Dianne BestParticipant @diannebest69516]

Thanks Martin – that has promise.

[duncan webster 1Participant @duncanwebster1]

You could look at SUJEN valve gear. It's a bit like slip eccentric, but you can power it from forward to reverse. Despite it's inventors claims it cannot deliver variable cut off. It was described in ME, I've tried googling to no avail. The eccentric is driven by a train of gears and you can change the angle of advance by moving the idler gears.

[Ady1Participant @ady1]

Heres a SUJEN article from 1996 (ME 3990)

Edited By Ady1 on 07/10/2016 01:28:14

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