AN IMPROVED COLD PRODUCING ENGINE
Year: 1873

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company,
Patent Agency, at Frankfort-on-the-Main, (Germany,) for the In-
vention of "AN IMPROVED COLD PRODUCING ENGINE."-A communication
from Trank Windbouson maiding of Rminatick Coomanal
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the
Office of the Commissioners of Patents, with his Petition, on the
26th September 1873.
I, FRANK WIRTH, of the Firm of Wirth and Company, Patent Agency,
at Frankfort-on-the-Main, (Germany,) do hereby declare the nature of
the said Invention of "AN IMPROVED COLD PRODUCING ENGINE," (a communi-
cation,) to be as follows:-
:-
This Invention relates to a novel combination of apparatus for cooling
atmospheric air to be afterwards employed for cooling the temperature
of rooms and liquids, for manufacturing ice, and for other analagous
purposes. This is performed by first drawing the air into a suitable

page_text: chamber, then compressing it in the presence of injected cooling water,
after which it is dried in a novel manner, and then allowed to expand
again to the pressure of the atmosphere, when it may be used for any of
the cooling purposes herein-before mentioned.
The apparatus consists of a cylindrical chamber, in which a well
fitting piston is caused by crank or other equivalent mechanism to
reciprocate backwards and forwards. Surrounding the outside of the
central portion of this cylinder an annular space is provided, which
communicates by means of open passages with the interior of the
cylindrical chamber, and is designed to receive the cooled air, which may
be led off by means of a pipe or pipes to any requisite outlet. Each end
of this cylindrical chamber further communicates at its lower side with
the outer atmosphere through a valve opening inwards, which admits
the air to be cooled, and also communicates at its upper side by two
passages (one being fitted with a back pressure valve) with a drying
chamber, in which a piston is fitted, which is open to the atmosphere at
the top, and is provided at the lower extremity of its rod with a louvre
perforated diaphragm, beneath which a layer of sponge is situated, which
is employed for extracting any moisture out of the air, which after
compression is brought into contact with such sponge, as herein-after
described.
The cylindrical chamber is further fitted with two auxiliary pistons,
one on either side of the main piston, which move simultaneously by
being connected together, but at a suitable distance apart by means of
parallel rods passing through stuffing boxes in the main piston; and
one of these auxiliary pistons is further connected to a small piston
working in a cylinder of smaller diameter, and forming by preference a
part of one of the covers of the cylindrical chamber. This smaller
cylinder is open to the cylindrical chamber at one side of its piston, and
also communicates through a pipe between the other side of its piston
and the other end of the cylindrical chamber. Each end of this chamber
is also connected by a pipe to a pump or injector of peculiar construction,
forming a part of this Invention, and consisting of a cylinder surrounded
by an annular chamber, which admits the cooling water to the pump
cylinder at the middle of the stroke of the plunger working within it
and at the proper moment for introducing such cooling water to the
cylindrical chamber, which is ensured by the rod of the pump plunger

page_text: being actuated by adjustable lever mechanism connected to the cross
head of the main piston.
The action of this apparatus is as follows:- Air being admitted to the
cylindrical chamber by one of the inlet valves, immediately the main
piston passes the passages communicating with the annular space
forming the outlet for the cooled air, it comes in contact with one of the
auxiliary pistons, and causes both auxiliary pistons (being connected
together) to advance along with it, so compressing the air on the front
side of one auxiliary piston and drawing in air with the other auxiliary
piston. This compression of the air first has the effect of raising the
piston in the drying chamber, and so distending the sponge beneath its
perforated diaphragm, at the same time the cooling water is admitted
into the presence of the compressed air by the action of the pump. The
main piston and the auxiliary pistons thus advance together until the
main piston reaches the end of its stroke, by which time the front
auxiliary piston has passed one of the passages leading to the drying
chamber, and thus admitted the compressed air between it and the main
piston, owing to the greater area exposed to the pressure on that side,
the auxiliary pistons are caused to advance to the extreme end of the
cylindrical chamber; the whole of the compressed air having meanwhile
passed through the distended sponge, by which means its moisture is
taken up. The return action of the main piston now commences; when
the piston in the drying chamber immediately falls and thus expresses
any moisture taken up by the sponge, the auxiliary piston now remains
at rest until the passages leading into the annular space are. passed by
the main piston in proceeding in the other direction, when the same
operation is repeated, and the cooled air after expanding again to the
pressure of the atmosphere escapes into the annular chamber ready to
be employed for any requisité cooling purpose.
30 SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frank Wirth in the Great Seal Patent Office of
on the 26th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
WIRTH, of the Firm of Wirth and Company, Patent Agency, at
35 Frankfort-on-the-Main (Germany), send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of September, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Frank Wirth, Her special
license that I, the said Frank Wirth, my executors, administrators,
and assigns, or such others as I, the said Frank Wirth, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED COLD
PRODUCING ENGINE," a communication from Frank Windhausen, a person
resident at Brunswick (Germany), upon the condition (amongst others)
that I, the said Frank Wirth, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Frank Wirth, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawings (that is to say) :-
This Invention relates to a novel combination of apparatus for cooling.
atmospheric air to be afterwards employed for cooling the temperature
of rooms and liquids, for. manufacturing ice, and for other analagous
purposes. This is performed by first drawing the air into a suitable
chamber, then compressing it in the presence of injected cooling water,
after which it is dried in a novel manner and then allowed to expand
again to the pressure of the atmosphere, when it may be used for any of
the cooling purposes herein-before mentioned.
The apparatus consists of a cylindrical chamber, in which a well
fitting piston is caused by crank or other equivalent mechanism to
reciprocate backwards and forwards. Surrounding the outside of the
central portion of this cylinder an annular space is provided, which

page_text: communicates by means of open passages with the interior of the
cylindrical chamber, and is designed to receive the cooled air, which
may be led off by means of a pipe or pipes to any requisite outlet. Each
end of this cylindrical chamber further communicates at its lower side
with the outer atmosphere through a valve opening inwards, which
admits the air to be cooled, and also communicates at its upper side by.
two passages (one being fitted with a back pressure valve) with a drying
chamber, in which a piston is fitted, which is open to the atmosphere at
the top, and is provided at the lower extremity of its rod with a louvre
perforated diaphragm, beneath which a layer of sponge is situated,.
which is employed for extracting any moisture out of the air, which
after compression is brought into contact with such sponge, as herein-
after described.
The cylindrical chamber is further fitted with two auxiliary pistons,
one on either side of the main piston, which move simultaneously by
being connected together, but at a suitable distance apart by means of
parallel rods passing through stuffing boxes in the main piston; and one
of these auxiliary pistons is further connected to a small piston working
in a cylinder of smaller diameter, and forming by preference a part of
one of the covers of the cylindrical chamber. This smaller cylinder is
open to the cylindrical chamber at one side of its piston, and also
communicates through a pipe between the other side of its piston and
the other end of the cylindrical chamber. Each end of this chamber is
also connected by a pipe to a pump or injector of peculiar construction,
forming a part of this Invention, and consisting of a cylinder surrounded
by an annular chamber, which admits the cooling water to the pump.
cylinder at the middle of the stroke of the plunger working within it,
and at the proper moment for introducing such cooling water to the
cylindrical chamber, which is ensured by the rod of the pump plunger
being actuated by adjustable lever machanism connected to the cross
head of the main piston.
The action of this apparatus is as follows:-Air being admitted to the
cylindrical chamber] by one of the inlet valves, immediately the main
piston passes the passages communicating with the annular space
forming the outlet for the cooled air, it comes in contact with one of the
auxiliary pistons, and causes both auxiliary pistons (being connected
together) to advance along with it, so compressing the air on the front
side of ouc auxiliary piston and drawing in air with the other auxiliary

page_text: piston. This compression of the air first has the effect of raising the
piston in the drying chamber, and so distending the sponge beneath its
perforated diaphragm; at the same time the cooling water is admitted
into the presence of the compressed air by the action of the pump. The
main piston and the auxiliary pistons thus advance together until the
main piston reaches the end of its stroke, by which time the front
auxiliary piston has passed one of the passages leading to the drying
chamber, and thus admitted the compressed air between it and the main
piston, when owing to the greater area exposed to the pressure on that
side the auxiliary pistons are caused to.advance to the extreme end of
the cylindrical chamber; the whole of the compressed air having
meanwhile passed through the distended sponge, by which means its
moisture is taken up. The return action of the main piston now
commences; when the piston in the drying chamber immediately falls
and thus expresses any moisture taken up by the sponge, the auxiliary
piston now remains at rest until the passages leading into the annular
space are passed by the main piston in proceeding in the other direction,
when the same operation is repeated, and the cooled air after expanding
again to the pressure of the atmosphere escapes into the annular chamber
ready to be employed for any requisite cooling purpose.
In order that this my said Invention may be the more readily seen
and understood, I have hereunto annexed a Sheet of Drawings illustrating
two modifications of my Invention.
Fig. 1 is a side longitudinal view partly in section of so much of a
cold producing engine constructed according to my Invention as is
necessary to explain its action; Fig. 2 is a side longitudinal section of a
modification of the cylinder of such engine.
In Fig. I. A is the main cylinder enclosed at either end by the covers B
and B'; C is the main piston secured at one extremity of the piston
rod C³, which passes through a stuffing box in the cover B', where such
piston rod is connected at its other extremity to a cross head C² guided
between the slide bars C³; D and D¹ are the auxiliary pistons, which are
connected together, but on opposite sides of the main piston C by the
parallel rods & and a passing through stuffing boxes formed through the
main piston, one of which is seen in section. The piston D is further
connected by means of a rod d³ with a small piston E working in the
small cylinder F, which by preference is cast in one piece with the

page_text: cover B (or may be affixed thereto in any convenient manner), and is
open to the interior of the main cylinder A, and to the back side of the
piston C at one end, whilst its other end is closed by the cover F¹, but
has a continuation of the rod d² passing through a stuffing box formed
in it in order that the action of the auxiliary pistons made be seen from
the outside, and also to afford a means of testing the degree of friction
with which they are working to and fro; and such small cylinder F
communicates with the far end of the main cylinder A, and with the
other or front side of the piston C through the pipe F*. The main
cylinder A communicates all round at its centre through passages J with
an annular space K surrounding the outside of the main cylinder, and
which space in its turn is open to the outlet pipe L designed for
conveying the cooled air to its required destination. At the bottom the
main cylinder further communicates at either end with the inlet
valves M and M', which admit the air to be cooled direct from the
atmosphere, whilst the smaller valves N and N¹ are opened at the same
time (for the purpose. of allowing the escape of the cooling water, which
would otherwise accumulate in the main cylinder) by having their
spindles resting upon the levers m and m¹ connected to the inlet
valves M and M', as illustrated. The top of the main cylinder is also
in communication at either end by means of two passages with a drying
chamber and O¹, which are fitted internally in a precisely similar
manner, and one of which drying chambers is seen in section, showing
the two passages marked respectively P and P', the former being
provided with a back pressure valve P and adjustable equilibrium
throttle valve P', which may be adjusted from the outside by an index
wheel, as seen on O¹. These drying chambers are each constructed with
a cylinder fitted with a piston ", which is open to the atmosphere at the
top, and is provided at the lower extremity of its rod with a louvre
perforated diaphragm. O³, beneath which a layer of sponge is situated
resting upon the perforated plate O*, and which sponge is employed for
extracting any moisture or water out of the air, which upon compression
is brought into contact with such sponge as herein-after described, and
which moisture or water escapes through the pipe Q into the space
surrounding the inlet valve M, and finally escapes by the smaller
valve N.

page_text: air is being compressed, and must instantly cease when the maximum
limit of compression has been reached. The compression of the air
begins when the piston C in reciprocating from one end of the cylinder
to the other passes over and so closes the passages J, when the injection
of water should commence at the end to which the piston is advancing.
For this purpose each end of the main cylinder A communicates by
means of pipes U and U' with a pump cylinder S, in which a piston V
is caused to reciprocate by having its rod connected to a lever V', which
in its turn is connected to the cross head C2 of the main piston, and
thus participates in the motion of such cross head and main piston. The
pump cylinder S is also surrounded by a passage marked S¹ opening into
an annular space S², which is in communication with the water supply
pipe S³, whilst the entrance to each of the pipes U and U¹ is provided
with a back pressure or ordinary pump valve T and T. By thus working
the injecting pump the injection of the water is ensured at the proper
instant, and the regulation of the quantity of water injected is obtained
by means of the lever X, which may be moved backwards or forwards
in order to shorten or lengthen the stroke of the pump piston V by
moving the connecting rod up or down the slot formed in the lever V¹,
as illustrated; and in order to spread the injected water within the
cylinder the mouth of each of the pipes U and U¹ is formed with a
spreading rose or finely perforated nozzle, as illustrated.
It is not absolutely necessary that the same description of pump as
that illustrated in the Drawing should be employed for introducing the
cooling water into the cylinder, as any other description of pump may
be employed, provided that it is arranged to admit the water only at the
proper intervals.
The action of the engine may thus be described:-The main piston C
is moved to and fro within the limits between a and b by crank
mechanism not shewn in the Drawing, because it presents no feature of
novelty. Now supposing that the main piston C has come in the
direction from 6 to a, and has arrived at the position marked I., and
that the auxiliary pistons D and D¹ occupy respectively the positions
marked II. and III., as the main piston C now proceeds and passes over
the outlet passages J it comes into contact with the auxiliary piston D,
when the three pistons D, D¹, and E, move forward along with such
main piston C, so compressing the air in front of the auxiliary piston D,

page_text: at the same time the cooling water is forced through the pipe U, and by
means of the spreading rose or nozzle is introduced in the form of thin
streams into the presence of the air undergoing the compressing process.
The compressed air presses now partly on the auxiliary piston D and
partly on the smaller piston E, and as long as the pressure on the
piston D is not quite equal to the pressure between the main piston C
and the auxiliary piston D the extra pressure of the smaller piston E is
not able to push the other auxiliary piston D' more than it is drawn
forward by the main piston, but when the piston C has reached the
position marked IV. at that instant the compressed air rushes through
the passage P in the direction of the arrow marked 1, 2, 3, and obtains
admission between the main piston C and the auxiliary piston D, so
almost equalising the pressure on both sides of such piston D, but owing
to the pressure still exercised upon the small piston E the pistons D and
D' are then instantly forced forward to the positions marked V. and VI.
The compressed cooled air in front of the piston D is thus forced through
the drying chamber O in the direction of the arrow 1, 2, 3, and takes up
its position between the piston D and the main piston. In this manner
the air whilst passing through the drying chamber O is drained of its
moisture, as will be now explained. Immediately that the air is com-
pressed in the cylinder A the small piston r rises in the drying
chamber O, and so lifts the louvre perforated diaphragm O³, and allows
the sponge lying beneath it to distend itself by its natural elasticity to
its fullest limit in order to be ready to take up the moisture from the
compressed air whilst rushing through the cooling chamber in the
direction of the arrow 1, 2, 3, as herein-before explained; the louvre
plates of the diaphragm Os being arranged to slant in a contrary
direction to the course of the streaming cooled air in order that any
moisture contained in such air may be deposited upon such plates and
so fall on to the distended sponge and be instantly absorbed. When the
pressure on the same side of the main piston falls below the pressure of
the atmosphere the louvre perforated diaphragm'O' instantly falls, and
thus the sponges are compressed between it and the perforated plate O',
so expressing the moisture or cooling water which then drains away
through the pipe Q. On the other side of the main piston C the cooled
and already expanded air is blown out through the outlet passages J, as
the auxiliary piston D¹ advances towards the position marked VI., as
herein-before described, whilst at the same time on the other side of
such piston fresh atmospheric air is drawn in through the valve M'.

page_text: It will thus be seen that at each to-and-fro movement of the main
piston C from a to b, and vice versa, the expanded cooled air contained
in such cylinder is blown out through the passages J and outlet pipe K.
The auxiliary pistons D and D¹ remain in the positions V. and VI. until
the main piston in proceeding in the direction from a to 6 passes over
the outlet holes J and comes in contact with the auxiliary piston D¹,
when the same operation as herein-before described is repeated on the
other side of the cylinder; the auxiliary pistons D and D¹ being pushed
for the distance beyond the stroke of the main piston by the compressed
air passing through the pipe F³ and exercising its pressure on the back
of the small piston E.
.
In order to avoid a knocking together of the main piston and the
auxiliary pistons it is arranged that such pistons shall never come into
close contact, but that a stratum of air shall be left between such pistons,
which acts as a cushion, and assists in starting the auxiliary pistons
in either direction, and to prevent such auxiliary pistons coming in
contact with the cover of the cylinder A at either end india-rubber
buffers B' are affixed in each of the covers, and for the same purpose
small segmental slides are attached to the upper edges of the auxiliary
pistons, which partially close the passages P at each end of their course
and so form an elastic cushion for stopping the movement of such
piston.
The main piston C may also be provided with india-rubber buffers on
each of its faces, and so still further assist in reducing the tendency to
knock together when the pistons approach each other.
The movement of the auxiliary pistons at the proper moment can also
be effected by a direct mechanical action, viz., by means of a crank and
rod, in which case the small cylinder F would be dispensed with and the
rod ɖ would pass through the cylinder cover B in order to be acted upon
by the crank and rod.
If it is required to cool and supply larger quantities of cold air with
the same stroke of piston in the engine herein-before described the
auxiliary pistons D and D' must be moved independantly of one another,
and the piston C made of a width or thickness equal to the length of its
stroke, minus the breath of the holes J, whilst the cylinder A must be
proportionately longer. The functions of the pistons D and D' remain
the same as described in reference to Fig. 1; they must, when the

page_text: corresponding side of the piston C has reached the end of its stroke, slide
to the end of the cylinder in order to drive the compressed air through
the drying chambers O and O¹. As soon as the piston C begins to open
the holes J the pistons D and D' slide from the corresponding end of
the cylinder up to the holes J, so forcing the cooled air away through
them on the one side, whilst on the other side they draw in air by the
inlet valves M and M'. An engine arranged in this manner is shewn in
Fig. 2, in which the pistons D and D¹ move independantly of one
another, so that the parallel rods d and d¹ (seen in Fig. 1) are dispensed
with. The pistons D and D' are each connected by means of a piston
rod with the pistons E and E¹ working respectively in the small
cylinders F and F¹. The forward motion of the pistons D and D' from
the end of the stroke of the main piston is effected by the pressure. of
the compressed air, as described in reference to Fig. 1; but the pushing
of such pistons up to the holes J in order to throw out the cooled air is
performed by the extra pressure on the back side of the pistons E and F¹,
which pressure is conducted through pipes from a reservoir in which it
is constantly stored. This air pressure must be less than the maximum
pressure in the cylinder A, and yet must be sufficient to slide the
pistons D and D' at the required instant up to the holes J.
It will be readily apparent that other arrangements might be adopted
besides the methods herein-before described for pushing the pistons from
the respective ends of the cylinder up to the holes J.
Having thus particularly described and ascertained the nature of the
said Invention, together with the best methods with which I am
acquainted for carrying the same into practical effect, I wish it to be
understood that I claim,-
1st. The general construction and arrangement of cold producing
engine for compressing and expanding atmospheric air in one and the
same cylinder and on both sides of the main piston C, and expelling
such air cooled according to the degree of expansion through outlets
formed within the course traversed by the piston by the respective
motions of the main piston C. and auxiliary pistons D and D', as and
for the purposes herein-before described and illustrated on the accom-
panying Drawing.
2nd. Constructing the holes J in the cylinder A within the course
traversed by the piston C, as and for the purposes herein-before described
and illustrated on the accompanying Drawing.

page_text: 3rd. The arrangements of the auxiliary pistons D and D¹ and methods
of actuating them, as and for the purposes herein-before described and
illustrated on the accompanying Drawing.
4th. The method of and apparatus for draining the air in the drying
chambers O and O¹, as and for the purposes herein-before described and
illustrated on the accompanying Drawing.
5th. The arrangement and construction of the injecting pump, and
especially constructing the inlet holes for admitting the injection water
at the middle of the stroke of the pump piston, whereby the admission
of the injecting water to the compressed air is ensured at the proper
moments, as and for the purposes herein-before described and illustrated
on the accompanying Drawing.
In witness whereof I, the said Frank Wirth, have hereunto set my
hand and seal, this Twenty-third day of March, in the year of
our Lord One thousand eight hundred and seventy-four.