IMPROVE- MENTS IN STEAM AND AIR ENGINES
Year: 1874

page_text: LETTERS PATENT to Jerome Harper, of Clinton Mills, Province of
British Columbia, North America, for the Invention of "IMPROVE-
MENTS IN STEAM AND AIR ENGINES."
Scaled the 8th May 1874, and dated the 17th March 1874.

page_text: NOW KNOW YE, that I, the said Jerome Harper, do hereby declare
that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed in and by the following
statement:-
My said Invention consists in superheating ordinary steam at the
instant of putting it under the piston of a steam engine, so that the full
value of the power developed by superheating it will be obtained in
driving the piston. To do this I construct an engine of a peculiar style,
which is at once compact and cheap, and which can be run with very
little expense for fuel.
In order to explain my Invention, so that others will understand its
construction and operation, reference is had to the accompanying
Drawings forming a part of this Specification, in which Figure 1 is a
perspective view of my engine; Figure 2 is a section showing the
cylinders in position over the fire-place; Figure 3 is a longitudinal
section in elevation showing the relative position of the parts.
A is a furnace, which may be constructed of iron or masonry, and is
provided with a fire-place M. B is an upright boiler, which is mounted
upon one end of the furnace A, so that the heat and products of com-
bustion from the furnace will pass up through the boiler and stack and
heat the water in the boiler in the manner of an ordinary upright engine
and boiler. Upon the opposite end of the furnace and directly over the
fire-place I set two upright open top cylinders C, C, so that their lower
ends extend down into the fire-place through the top of the furnace.
The pistons D, D, each consist of a tube of the desired length having a
partition or diaphragm passing across its middle, thus forming a double
cup-shaped piston, the tube serving as a guide to the moving piston.
The pitman F of each piston is secured to the center of the diaphragm
at its lower end, while its upper end is secured to a crank on the crank
or driving shaft g. The pistons move up and down in the open topped.
cylinders, being connected by their pitmen to double cranks on the
crank shaft, so that the upward movement forces the other down
alternately.
If desired the cylinders C, C, can each be constructed with an inner
tubo which is smaller than the evlinder and inside of which the niston.

page_text: and tube will be closed, and the tube will not extend quite to the bottom
of the cylinder, thus providing a space or jacket between the two, which
communicates below the tube with the space below the piston. Suitable
packing is secured around the pistons in order to render them steam-
tight in the cylinders. A tube p, which is provided with a proper valve,
connects either with the space below the piston or with the. jacket
between the cylinder and its inner tube, through which a quantity of
air will be drawn by the pumping action of the piston after the exhaust,
valve closes, and before the steam port is opened for the up stroke of
the piston. These air valves can be used or not, as desired, my improve-
ment in working steam not depending upon them further than to use
them as accessories.
R is the steam chest, into which the steam is conveyed from the
boiler by the pipe S, and T is the exhaust pipe, which conveys the
exhaust steam after each stroke of the piston to the smoke stack. The
steam valve is operated by crank U, connecting link V, and eccentric W
from the main driving shaft g.
The fire which heats the water in the boiler also heats that portion of
the cylinders C, C,' which extends down into the fire-place, and when
thus heated the steam which is admitted below the pistons is suddenly
superheated by coming in contact with the heated chamber, and its
power is greatly multiplied at the very instant and in the exact situation
in which it will work effectively.
Superheated steam has heretofore been used in steam cylinders, but
it has always been superheated in an intermediate heater between the
boiler and engine, and introduced into the cylinder in a highly heated
condition. While the cylinder was at a much lower temperature, and
while much better results were obtained in this way than in using steam
at ordinary temperatures, the conditions were such that the cylinder and
piston were soon destroyed by the action of the superheated steam; but
by my plan the cylinders themselves are kept at the highest temperature
and made to serve as superheaters as well as cylinders, giving the
additional advantage of utilizing the explosion or sudden expansion
caused by superheating at the instant the expansion occurs.
In the present case I have shown an ordinary slide valve for working
the steam, but it is manifest that any of the known methods of admitting
steam and cutting off at different parts of the stroke may be employed

page_text: as may be found most suitable for the style of engine to be used by actual
tests with my engine. A resulting advantage of three to one is obtained
by using steam superheated on cylinder heaters as above described over
the use of steam at ordinary temperatures.
I am aware that water has been injected into the cylinder and there
converted into steam under the piston, I therefore do not claim con-
verting water into steam beneath the piston, but what I do claim as new
and desire to secure by Letters Patent is,―
1st. The method herein described for working steam consisting in
introducing steam from the boiler into the steam chest and cylinder and
superheating it at the moment it is introduced under the piston, as set
forth.
2d. The boiler B in combination with the furnace A and open topped
cylinder D arranged to set into the fire-box, and having suitable steam
connections, as set forth and for the purpose described.
3rd. The cylinders C, C, either with or without the air valves p, in
combination with their double cup-shaped pistons D, D, pitmen F, and
crank shaft g, substantially as and for the purpose above described.
In witness whereof, I, the said Jerome Harper, have hereunto
set my hand and seal, this Twentieth day of February, in
the year of our Lord 1874.
TADATTATOR