Author Topic: Short video - steam engine with unusual reversing arrangement.  (Read 165 times)

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1002
  • North Yorks - UK.
Hi,

I came across this slightly unusual engine while browsing youtube and thought it may be of interest. It looks to be a small full size boat engine but has an unusual reversing set up.


Anyone got any thoughts on how it works ?  I'm assuming the brass plunger alters the path of the steam flow but I still can't be certain what is happening inside. It looks to have just 1 eccentric per cylinder with the steam chest(s) between the cylinders.

If it was a successful design I wonder why it wasn't more common, presumably it is easier to make and maintain than a Stephenson link ?

Offline MJM460

  • Full Member
  • ****
  • Posts: 552
  • Melbourne, Australia
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #1 on: June 12, 2018, 01:15:22 PM »
Hi Gas Mantle,

I wonder if the reversing gear is an external hand operated piston valve, which swaps around the supply and exhaust.  This will not work on the small engine which appears to have slide valves, but the larger engine may have piston valves which lend themselves to reversing this way.

Unfortunately the film did not say much about the engines or how they work, and in fact seemed surprised that the larger engine did reverse.  The few quick views of the top head did not make it easy to determine what kind of valves were utilised.

MJM460


The more I learn, the more I find that I still have to learn!

Offline Jasonb

  • Full Member
  • *****
  • Posts: 5438
  • Surrey, UK
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #2 on: June 12, 2018, 01:23:17 PM »
+1 for piston valve and a way of diverting the inlet & exhaust.

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1002
  • North Yorks - UK.
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #3 on: June 12, 2018, 01:48:39 PM »
I did think it may have piston valves but it's still a bit of a mystery how a the plunger swaps the inlet and exhausts on a twin double acting engine ?

Whatever is going on inside the plunger housing and steam chests looks to be compact and it appears to work well so I'm wondering why it wasn't more common ?

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 11114
  • Hampshire, england.
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #4 on: June 12, 2018, 02:34:18 PM »
Yes it uses Piston valves and has a steam control valve that has a hollow bobbin for reversing the steam feed  ;) The problem with them is that piston valve engines have a habit of consuming more steam as you cannot provide any lap on the valves as you have to set the eccentrics at 90 degrees to allow for reversing. And small piston valves have a habit of leaking after long periods of use  :facepalm:

Peter if you want to make a piston valve engine then the Borderer by John Bertinat is available.

Jo
Usus est optimum magister

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1002
  • North Yorks - UK.
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #5 on: June 12, 2018, 02:46:05 PM »
Thanks Jo I have made a few small piston valve engines (Stew Harts potty series are piston valve engines) and they do work well but I was looking at this engine more as a matter of interest.

Having said that I do want to start building a fairly big engine to my own design later in the year so I keep drooling over the small engine in the video pondering whether something like that is possible on my 10x22 Chineseum bench lathe and mill.  :)

Here's another video of the same 2 engines



Offline Jasonb

  • Full Member
  • *****
  • Posts: 5438
  • Surrey, UK
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #6 on: June 12, 2018, 02:52:53 PM »
I keep drooling over the small engine in the video pondering whether something like that is possible on my 10x22 Chineseum bench lathe and mill.  :)

Anything is possible :LittleDevil:

Offline Gas_mantle

  • Full Member
  • ****
  • Posts: 1002
  • North Yorks - UK.
Re: Short video - steam engine with unusual reversing arrangement.
« Reply #7 on: June 12, 2018, 03:11:49 PM »

Anything is possible :LittleDevil:

You reckon it's achievable then ?

I kinda want to build something reasonably big that could do some real work if it was needed. (I don't necessarily want an engine for a specific job, I just want something I know could do real work).

When I upgraded my lathe to a 10x22 last year the 2 main reasons were I wanted a 10" turning capacity and T slots on the crosslide to bore larger cylinders between centres.