Improvements in Hot-air Engines.
Year: 1899

page_text: Date of Application, 12th Oct., 1899-Accepted, 16th Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Hot-air Engines.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention, (which has been
communicated to me from abroad by A. Wolf, Junior & Company, of Bleich-
strasse, No. 4, Frankfort-on-Maine, in the German Empire) and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
a
This invention relates to hot-air engines and it has for its object to provide
motor in which very effective and complete cooling takes place and a great
difference of temperature is maintained between the different parts of the dis-
placing cylinder.
In the accompanying drawing Figure 1 represents in vertical section an appara-
tus constructed in accordance with this invention.
Figure 2 is a cross section through the upper part of the displacing cylinder.
Figures 3 and 4 shew the governors or regulators separately as hereinafter
described.
b
In an engine constructed in accordance with this invention the upper part a of
the displacing cylinder is provided with cooling plates (preferably vertical and
radial) and at one side above these plates bis arranged a ventilator c, worked by
the motor the said ventilator forcing cool air into the spaces between the plates b,
whilst the motor is working so that thereby the upper part of the cylinder a is
kept very cool.
To obtain a further cooling of the upper part a of the displacing cylinder, the
lower part thereof is made of porcelain or equivalent material and is secured
to the underside of the base plate e, the metallic upper part a being secured to
the upper side of the said base plate, the consequence being that heat from the
lower part d is not conducted to the part a so as to be detrimental to the working
of the engine.
The lower part d and its isolation from the upper part permits of permanently
heating the part d to a far higher temperature than has been heretofore possible.
The heating may for example be raised so as to attain even a white heat,
A good effect may be moreover obtained if the displacer f be likewise made of
porcelain, or like material, so that it is not liable to be injured by the intense
heat and is less liable to convey heat to the upper part a of the displacing cylinder.
The aforesaid parts which are described as being made of porcelain or the like
may be made of very thin sheet metal the inside and outside of which are covered
with enamel or the like capable of protecting the metal from corrosion and being
a non-conductor of heat.
A. hot-air-motor constructed in this manner, under otherwise equal conditions,
is of an efficiency amounting to thirty per cent. more than that of such motors as
previously made.
In order that the working of the machine may always be kept as constant as

page_text: possible it may be fitted with a governor or regulator constructed in the following
inanner.
A tube 9 closed at the top has its open bottom end screwed into an opening in
the piston h the interior of the said tube being in direct communication with the
interior of the cylinder as shewn and being provided with a slot i over which
a slider shewn as a ball k is adapted to slide up and down on the tube g the said
slider being held between two springs 7 and m so that normally it will completely
close the slot i and the springs and m are so strong that, as long as the engine
retains its normal speed, the slider will retain this normal position. When the
speed of the engine exceeds its normal limit, the slider is displaced by reason
of the inertia overcoming the action of the springs, thus causing the slot i to
be uncovered the consequence of which is, that the interior of the cylinder is
placed in communication with the outer air and that a partial equalisation is pro-
duced, the effect of which is that the speed of the motor is reduced.
Figure 3 illustrates the said slider in the position in which the slot is com-
pletely covered, whilst in Figure 1 the slider is shewn in the position in which
the upper part of the slot is opened.
In order to impart to the governor or regulator a great sensitiveness, the con-
struction represented in Figure 4 may be used.
The lever o carries a weight (shewn in the form of a ball) and is centered at p
and is so balanced by a spring g that the widened part of the lever situated upon
the slot in the tube covers the slot, when the engine is working at normal speed.
When the speed of the engine increases, the lever o moves so that the portion
of the lever which covers the slot, will slide away from over the slot to a corres-
ponding extent, and place the interior of the cylinder in communication with the
outer air as in the first described arrangement.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:
1. In hot-air engines, a displacement cylinder having the upper part provided
with cooling plates, in combination with a ventilator, substantially as, and for the
purpose, hereinbefore described.
2. In hot-air engines, a displacement cylinder having its lower part formed of,
or covered with, porcelain, or equivalent non-conductor of heat, substantially as,
and for the purpose, hereinbefore described.
3. In hot air engines, a displacer made of, or covered with, porcelain, or equiva-
lent non-conductor of heat, substantially as, and for the purpose, hereinbefore
described.
4. In hot air engines, a displacement cylinder having the lower part made of,
or covered with, a non-conductor of heat; and an upper part provided with plates,
and means for causing air to pass between them and a displacer made of, or covered
with, a non-conductor of heat; substantially as, and for the purpose, herein before
described.
5. A regulator, or governor, for hot air engines, the said regulator, or governor,
consisting of a tube closed at the top and opening through the piston into the
cylinder and provided with a slider supported between springs and capable of
closing and opening a slot in the said tube substantially as herein before des-
cribed.
6. A regulator, or governor, for hot air engines; the said regulator, or governor
consisting of a tube closed at top and opening through the piston into the cylin-
der, and provided with a balanced lever capable of closing and opening a slot in
the said tube; substantially as hereinbefore described.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.