Subject: Re: Oscillating and Ericcson Engines?

From: [email-masked] (Jim Shockey)
Date: 21 Jul 1996 06:31:01 -0700

In article <[email-masked]> [email-masked] (dsg) writes:
>From: [email-masked] (dsg)
>Subject: Oscillating and Ericcson Engines?
>Date: Sun, 21 Jul 1996 05:36:27 GMT

>Could someone tell me how the oscillating steam engine works?
>I have seen pics of it, and it apparently does not seem to have 
>any obvious valves. Is this engine that simple? Is it only
>for special low power purposes or can it be upscaled for
>heavy work?

Take a look at the drawing found at the 
following URL:

http://www4.infoanalytic.com/modeltec/dodi.htm

This should explain the basic principle of 
the thing. How much work you can get out 
of one, I don't know. But, I bet someone 
here could give us an idea. 

Good luck,

--jim			<[email-masked]>

---

From: [email-masked] (Mick Collins)
Date: Sun, 21 Jul 1996 18:45:21 BST

[email-masked] (Jim Shockey) wrote:

> . How much work you can get out  of one, I don't know. 

  Small oscillating steam engines developing several HP were
once made as 'wall engines'.  Mounted directly on the wall of
a shop they took up little space and were used for driving
machines of all kinds.  These were often fitted with some
form of valve gear to permit expansive working..
  Much larger oscillating engines up to several hundred HP 
were used in early paddle steamers.  These invariably had
valve gear to allow the ship to run astern.

  The Ericsson (cycle) engine is a complicated type of hot air
engine using valves.  Although many hundreds were made in FHP
sizes, they were not popular due to noisy operation and valve
trouble.  So Ericsson turned to the Stirling cycle in which
the same air is alternately heated and cooled to create the
pressure variations needed to drive the power piston.  No 
valves are used and although efficiencies were low these 
engines were made in large numbers and gave good service.

  Most of the remaining Ericsson engines and virtually all
the model engines, are of this later design - apart from the 
linkage, they are virtually inverted copies of Stirling's 
first engine.

  Incidentally, Ericsson originally intended his engine to
run on solar heat and "bring power to the desert".
  -- 
      Cheers - Mick

---

From: Pat Kelley <[email-masked]>
Date: Mon, 22 Jul 1996 15:50:22 -0500

> >for special low power purposes or can it be upscaled for

	The way it works is that the cylinder has a port in the side
facing its support bracket, and the cylinder itself pivots up and
down, connecting the port alternately to the steam inlet and the 
exhaust port, which are in the ctlinder support bracket. I don't
imagine that it could be scaled up too much. The Ericsson engine,
which was really  more of a brand name than something very different
>from  the Stirling, often did supply useful power in small sizes.
The Stirling engine mutated through many strange and surprising
forms during its heyday, and the only real difference between the
Ericsson and the Stirling engines was that Ericsson's did not use a
regenerator, or "economiser" as Stirling called it. This made them
simpler but less efficient, not much of an issue when fuel is cheap.
And then, if course, the internal combustion engine killed them both.

-- 
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               Pat Kelley ([email-masked])
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