AN IMPROVED MACHINE FOR PRODUCING COLD AND MOTIVE POWER
Year: 1874

page_text: LETTERS PATENT to Hugo Nehrlich, of Frankfort-on-the-Maine, in
the Empire of Germany, Civil Engineer, for the Invention of "AN
IMPROVED MACHINE FOR PRODUCING COLD AND MOTIVE POWER."
COMPLETE SPECIFICATION filed by the said Hugo Nehrlich at the
.
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 29th May 1874, pursuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUGO
NEHRLICH, of Frankfort-on-the-Maine, in the Empire of Germany,
Civil Engineer, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED
MACHINE FOR PRODUCING COLD AND MOTIVE POWER," and have petitioned Her
Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and have made solemn Declara-
tion that I verily believe myself to be the first and true Inventor
thereof.
NOW KNOW YE, that I, the said Hugo Nehrlich, do hereby declare
that the following Complete Specification under my hand and scal fully

page_text: i
.
describes and ascertains the nature of my said Invention, and the
manner in which the same is to be performed, reference being had to the
Drawing hereto annexed and forming part of this Specification, and to
the figures and letters marked thereon, that is to say :-
-
This improved machine for producing cold air and motive power is
based on the application of the known principle of the compression and
expansion of atmospheric air, causing the latter during the action of
expansion to perform external labour, and by this means to abstract heat
from the atmospheric air and convert it into motive power, and on the
other hand produce cold air which may be employed for cooling rooms,
ice making, or for other refrigerating purposes. I am aware that this
principle is employed in the construction of the freezing and ice making
machine for which Letters Patent were granted to Franz Windhausen,
of Brunswick, and dated the Fifth day of March, one thousand eight
hundred and sixty-nine, No. 669; but although the principle is the same
the arrangement and construction and the application are different, thus
rendering my improved machine for the production of cold air and
motive power new in its essential parts and in their combination.
By my improved construction of machine the motive power or steam
produced is not only sufficient to work the machine for the production
of cold air, but leaves a surplus which may be utilized for other purposes.
The improved machine is constructed of four separate apparatuses
connected together and working in combination, and consisting of a
compressing cylinder, refrigerators, an expansion cylinder of an injection
pump, and also of a steam engine.
To make my Invention better understood I will now proceed to
describe the same by reference to the accompanying Drawing, confining
my description to the essential or new parts of my improved machine
and its action..

page_text: upper escape pipe is provided for the water as it becomes heated whereby
the cylinder is kept cool, thus carrying off at the point of cooling of the
compression heat a part of this heat, and lessening the expenditure of
power required for the compression of the air in the cylinder.
The piston, piston rod, and their connection with the beam of the
engine are of known construction, and therefore require no description.
The arrangement and construction also of the inlet valves e, e, and of
the outlet valves a, a, can be easily understood from the Drawing.
The mechanism by which the opening and closing or regular alternate
play of the valves is obtained is as follows:-The outer ends of the rods
of the inlet valves e, e, are jointed to rods by means of parallel levers
which are moved intermittently by the beam of the engine, and the rods
with the now open valves connected with them are at the required
moment, that is to say, at nearly the end of the stroke closed by the
beam against the atmospheric pressure, so that at the commencement of
the reverse movement of the piston they will be shut, and will not allow
any of the inclosed air to escape as would be the case if automatic valves
were employed.
One end of the rod of each outlet pressure valve a is jointed to a lever
having at its other end a rod or bolt passing through the cylinder cover;
the length of this rod or bolt is such that when the valve is completely
open the said rod reaches as far into the interior of the cylinder as the
distance between the double seats of the valves, so that the valve is
completely closed by the return of the bolt to the level of the inner
surface of the cylinder cover, as shewn in detached view at Figure 2.
Thus it is that the outlet valve will completely close at the moment
when the piston reaches the end of its stroke, that is to say, just at the
required moment. The valve remains closed as long as it is requisite,
videlicet, until the opening of the outlet valve opposite to it is effected
by the pressure of the compressed air behind the valve, which air com-
municates by side openings in the valve box with the refrigerating space.
The alternate opening of the outlet valves takes place as soon as by the
compression of the air in the cylinder an excess of pressure over the
atmospheric pressure behind the valve becomes effective, that is to say,
as soon as the maximum of compression required has been attained.
The refrigerators K and L which I employ are for the sake of clear-
ness shewn placed at the side of the compressing cylinder, but they may

page_text: be placed in any other suitable position, and are of the known tubular
construction in which the compressed air passes through tubes sur-
rounded by cold water. The refrigerator and also steam generator K is
made in the form of a field steam boiler, and the water in the tubes is
surrounded by hot air. Above this apparatus is a steam chamber with
the usual appendages, such as a safety valve and a glass gauge of an
ordinary steam boiler. The hot compressed air which comes from the
compressing cylinder passes first into the steam generator K, then into
the refrigerators L, and thence through the tube H into the expansion
cylinder E, while the cooling water is conducted first through the tube
W into the refrigerator, then from the second refrigerator into the annular
space round the compressing cylinder, and is brought finally into the steam
generator in the form of high pressure steam. The waste water which
accumulates in the air pipes from the compressed air by the lowering of
the temperature is collected in the bottom of the refrigerator chamber,
and is drawn off from time to time by means of the cocks f. From this
description it will be understood that the refrigerating apparatuses
operate on the counter current principle, that is to say, the cold water
comes first in contact with the coldest air, and is converted finally into
steam by means of the most heated air. The expansion cylinder E
which I employ is also placed vertically like the compressing cylinder,
and for the same reason the expansion cylinder is surrounded by a
second cylinder or jacket, the annular space thus enclosed communi-
cating with the slide box P of the expansion slides i, i, and into which
the compressed air from the refrigerator enters through the tube H. A
stop valve closes communication between this annular space and the
outlet ports o, 0.
.
The waste water which may still accumulate in the compressed air in
the annular space may be discharged therefrom by a suitable cock.
From the annular space the compressed air enters the slide box P and is
admitted alternately through the revolving inlet slides i, i, into the
ernension aulinder and scanes therefrom through the outlet slides a

page_text: The injection pump J which I employ is represented in two sectional
views at right angles to each other at Figures 3 and 4. This pump is
placed between the compressing and the expansion cylinders and is only
an auxiliary, which by the direct injection of water into the compressing
cylinder at the moment of the greatest heat development of the com-.
pressing operation serves to protect the cylinder and piston from a too
intense heat. This pump is not essential to carrying out the principle of
my improved machine, but is employed for additional safety. It is so
constructed that it receives its motion from the pressure of the com- .
pressed air which enters from the compressing cylinder through two
tubes alternately in the upper and lower parts of the same into the
spaces p and p of the pump, and on the opening of the inlet valve at the
corresponding side of the compressing cylinder is sucked back.
The construction of the pump is such that the piston arcas on which
the atmospheric pressure acts are larger than the piston ring areas which
work in a contrary direction to the water; it is obvious that the pump
during the compression of the air in the compressing cylinder injects its
water into the same.
The operation of the machine is as follows: - Assuming that on
putting the machine in motion the compressing piston is at its lowest
point, and the expansion piston is at its highest point, in which position
all the valves of the compressing cylinder and the slides of the expansion
cylinder will be closed, on the elevation of the compressing piston the
lower inlet valve e is at once raised by the external atmospheric pressure
and sucks in atmospheric air through the opening S.into the cylinder,
the upper inlet valve remains shut at the commencement of the com-
pression of the air, whereas the outlet valve will open by this pressure as
soon as this pressure becomes a little in excess of the pressure upon the
valve..
The lower outlet valve a is kept shut during the elevation of the
piston by the excess of pressure of the air under it entering from the
refrigerators into the valve box. By this means when by the elevation
of the compressing piston the fixed maximum of compression of the air
in the cylinder is attained, the upper outlet valve a opens and admits
the compressed air warmed by the action of compression into the
refrigerators L and K.
The compressed air cooled and thereby liberated from steam and water

page_text: expansion cylinder E, and the slide box P of the inlet ports communi-
cating with it for the purpose of being further cooled on the cold surface
of the cylinder, and for the condensation of any steam which may still
remain in it. The object of this arrangement is to withdraw the residue
of steam or moisture from the air or to abstract it here in the form of
water, so that it may not become snow in the expansion cylinder, and
thereby develop oxygen, but be used for the purpose of expansion in
the expansion cylinder where it serves in the same manner as in an
expansion steam engine for the working of the piston, and by this work
loses its still latent heat relatively changing it into power, and becoming
cold, finally escaping through the opening A, and being applied to the
cooling of a room or making of ice.
By the descent of the compressing piston and the consequent elevation
of the expansion piston the same operations are repeated, and by the
continuation of the piston's movements the normal function of the
machine begins. As by the process of cooling the compressed air
without loss of tension loses in volume, a smaller volume of the
expansion cylinder is required which will not therefore produce so much
power as the compressing cylinder consumes. The difference is adjusted
by a Corliss' steam engine working the other end of the crank shaft
which draws its steam from the steam generator, and still leaves a large
portion of steam for further application.
Having now described my Invention and the best means I am
acquainted with for carrying it into effect, I would have it understood
that I do not claim the parts herein-before described taken separately,
but what I do claim and intend to be protected by the said Letters
Patent is,―
Firstly. The vertical arrangement of the various parts of the machine
with the beam placed underneath, in combination with the peculiar
method of working the inlet and outlet valves of the compressing
cylinder, and the Corliss' method of working the inlet and outlet slides
of the expansion cylinder for the purpose of lessening the power required
for the movement of the compressing piston by diminishing the friction
and securing an exact opening and shutting of the slides, as also the
easy regulation of the latter, as herein-before described and represented
in the accompanying Drawing.
Secondly the surrounding the compressing cylinder with cold water
for the purpose of abstracting from the air during the action of com-

page_text: pression, an essential part of the compression heat, and thus effecting a
saving in the expenditure of power for the piston movement, that is to
say, increasing the effect of the machine, as herein-before described and
represented in the accompanying Drawing.
Thirdly. The application of the double-acting water pump with
differential pistons working under the pressure of the compressed air of
the machine, in a manner corresponding to the working of the latter for
the purpose of obtaining a regular water injection into the condenser,
and into the annular space around the compressing cylinder, as herein-
before described and represented in the accompanying Drawing.
Fourthly. The forming an annular space round the expansion cylinder
for the purpose of condensing the residue of steam remaining in the
compressed air on the largest area of the coldest part of the machine
before the air enters the expansion cylinder, and by this means pre-
venting heat being produced in the latter by the changing of the
aggregate condition of the atmospheric moisture, and so preventing the
piston movement being obstructed by the formation of snow, as herein-
before described and represented in the accompanying Drawing.
Fifthly. The method of applying a steam generator for the purpose of
changing the heat withdrawn from the air into steam, as herein-before
described.
In witness whereof, I, the said Hugo Nehrlich, have hereto set
my hand and seal, this Twenty-sixth day of May, in the year of
our Lord one thousand eight hundred and seventy-four.