The Gloy engine
Since some longer time not being in my workshop, I recovered an idea of a Stirling design from Robert Sier's book, which looked quite interesting, at least for hobbyist's engine.
It's the Gloy engine (Patent by W.Gloy;1877;
Holzminde(sic?>Holzminden?)Germany)
It's basic design is to use a turning (back and forth; not a rotating one
!) displacer, a segment, to displace the gas. This has the advantages/features,
that
- the rod, to move the displacer, is only turning (side force
reduction&sealing advantage)
instead of moving back and forth,
- a very compact engine with high swept volume can be built.
- (specially for hobbyists without access to a lath) common compounds
(like cans etc.) can be used to build an engine.
As I usually do, I've built a proof-of-concept
engine
,
that run on an alcohol burner.
I've modified the original Gloy design to achieve a more compact design,
although MANY OTHER modifications to the Gloy are possible and may by far
better than my proof-of-concept engine!
As you might easily find out, the basic design of using a turning displacer can be as well applied to other basic designs we know. So the Gloy-concept can be modified for a
- Ringboom or
- Free piston or
- Liquid Piston or
- Moving cylinder engine
Of course, there is more that has to be evaluated for a Stirling engine, but in principle the forces(and sizes) are similar in a Gloy to a classical cylinder engine:
- about the same relation of displacer volume to swept volume
- about the same relation of heating/cooling surfaces
- vibration forces will be as much as in a classical cylinder, except that
the vibrational forces will be 'turning' instead of back and forth.
From the thermodynamic point of view, the advantages of the Gloy-concept
are not that much impressing, (in relation to a classical cylinder/piston
engine)
BUT>> from the hobbyists point of view, the advantages are SIGNIFICANT:
- most easy and cheap to achieve compounds, like cans, oil barrels etc.
and even the displacer can be build(by soldering) from another can,
- you can solder it,
- get a quite precise geometry, without much work, or special tools,
so the hobbyist can build a rather precise and accurate engine
- a quite airtight cylinder, when you lead the displacer's axis through a
brass tube with an inner
diameter of the axis.
- and even the cooling water jacket is easy to build, by using a half of
a
same sized can.
Some pictures of the Gloy I did:
