Some time ago, I found a new version of a valve gear which delivers really good valve event diagrams and does not need an open loop.
The structure of the parts involved is similar to the parts of Baker valve gear. The kinematical structure is similar to Walschaerts valve gear.
If interested, take a look at https://steamtec.s-a-s.ch/?box=valvegear/new_valvegear and request access to get more info.

If you have other concerns about valve gears, see my former article via viewtopic.php?f=1&t=48134 .

Good morning! Just curious, what software are you using to model valve events? I've toyed with the idea of working things up in Solidworks... or COMSOL... and running full thermodynamic simulations, but just haven't had time to dig in.

My dream would be a full thermodynamic model from firebed to stack, with various PV diagrams for various valve gears... along with accessories such as feedwater heaters and all the incarnations of exhaust nozzle setups.

Its probably way more than I have time for, but it might be possible, given today's finite element / CFD codes.

Just a thought.

The new valve gear was modeled in my own online program, at the moment without a detailed adjustability yet. You can see a runnning demo cover with my program on the SteamTec website linked in my signature.

For optimizing a valve gear, it does not make sense to include a thermodynamical calculation. The optimization rules and targets are not very complex and definitely do not include the properties of steam and heat.

I am in contact with someone working on a thermodynamical simulation (tool?). If you like to get in contact with him, please send me a PM with your email address and I will forward your desire to him.

I tried to take a look at the link on my government computer and it said that site was blocked under the category of pornography. Now I like a good valve gear as much as the next guy but that seems a bit excessive!

This is something I understand very well!
It seems to me that the spam filter AI is electrified and her hormones are driven crazy by the reciprocating movement of the valve gear parts and piston in the running demo left on bottom of the website :-D

Those of a certain age may remember

"Round and round went the big red wheel,
In and out went the spike of steel"

An actually functional kind of Raymond valve gear?

I do not think so, but I did not find any info about Raymond valve gear on the web.

It's a French poppet valve gear from the early Thirties. I think it is covered on either Thierry Stora's or Claude Bersano's sites (it may take some wayback-machine searching to locate them now) and for some reason I remember pictures and a short discussion coming up in conjunction with the search to find the 'right' salmon-rod mass and distribution for Cossart valve gear.

It had external pushrods for drive, and it shared with early Caprotti a surprising underestimation of the forces and stiffness required for proper operation on an express steam locomotive.