Rotary valves

[Anatol]

I was appending this note to my last post but it seemed to be a new thread.

I was doing a valve job on my old Toyota pickup and marveled at the weight of the timing chain and valve springs. I thought - it takes a lot of energy to throw those valves up and down at speed. It seems that an alternative to the reciprocating valve would be a great advance, and some kind of rotary device makes (theoretical) sense.

There's great website Museum of Retro Technology, which has an almost encyclopedic listing of engine designs (EC and IC). The owner, Doug Self, is very pessimistic about rotary anything, and documents the sad history of failed attempts to make rotary valves.

I'm not saying I can buck the trend, but I'm going to try (fools rush in). There seem to be several possible topologies which offer great efficiencies in terms san er energy and reduction of moving parts.
Each with its own problems. Clearly seals are one of the big issues. I'm intrigued by the possibility of labyrinth seals.
The shapes I've thought about include:
1. rotating variant of spool valve,
2. hollow rotating tube valve,
3. rotating disc
4. etc
If anyone would like to discuss these issues, I'd be glad to hear from you.
thanks!

 

[Anatol]

I found a nice page on a Westbury Gemini build (and variants) by Graham Meek here -
http://modelengineeringwebsite.com/HS_Steam_engine_trio.html
These engines use (versions of?) ETWs original rotary valves (and a toothed timing belt).
Has anyone had experience making or using such valves? They have axial and radial passages (?) I'm not sure how this worked - still looking fir drawings of the steam chest.
They also have no obvious seals. very curious.

 

[Anatol]

continuing discussion that started at
https://www.homemodelenginemachinist.com/threads/rotary-valve-twin-steam-engine.8805/page-2

It seems the term 'rotary valve' or orbital valve' can mean several things.
As Gary explained, Kouhoupt used part of the crankshaft as a rotating valve with milled passages.
Westbury made something he called an orbital valve for radial engines -(roughly) a disc mounted in the crankshaft. Both these styles reduce moving parts but extend steam passages.
Westbury also discusses a vertical rotary valve driven by bevel gears serving both cylinders
Meeks shows belt driven overhead rotating valves on a 3 cylinder gemini (also Westbury).
Bogstandard/Blogwitch's Puddleduck has, I think, hollow rotating overhead valves.

I'd be pleased to hear reports/opinions on any of these or other variants.