rocker valve engine

[sacandaga]

Took a ride to Long Lake NY last week to check out the remains of the S.L. Buttercup ( launched in 1882 , sunk in 1885 and brought back to the surface in 1959) which now reposes behind the Long Lake town hall. It is in a caged-in area and could not get close enuff to check out the engine completely, but what I did find was very interesting: the engine was made by J C Todd of Newark, NJ and appears to have been designed by William Baxter (of Colt Baxter fame). This is a typical 4 column, single cylinder vertical, crosshead feed pump engine, bore & stroke estimated as 4x4. What is unsual was a rocking valve instead of a slide valve and a slip eccentric instead of a Stevenson reverse. (I took pics but my "puter will not upload them now). A sketch of this engine can be seen on the back cover of "Steamboating" ,issue 56, winter '94 with the article on page I-- 1-31.
The reason for mentioning this is because I would like to know how the rocker valve works and if any of the readers have had experience with this design (I'd like to put in the engine I'm building for my launch as it seams much simpler than a slide or a piston valve. Thanks, John

[barts]

If rocker valves are not tapered, they don't seal very well for very long. A slide valve is very simple and self adjusting for wear, but does result in high forces if not balanced. Piston valves solve this, but are more complex to make and really need rings and sleeves for long wearing.

- Bart

[Lopez Mike]

What does a rocker valve look like? Don't think I've heard of that one.

[racerfrank]

I always thought a rocker valve was like a Corliss engine, or is it more of a rotating valve that doesn't go all the way around?