IMPROVEMENTS IN AND APPERTAINING TO MACHINERY FOR COOLING ATMOSPHERIC AIR, PART OF 'WHICH INVENTION IS ALSO APPLICABLE TO MACHINERY FOR COMPRESSING AIR PROVISIONAL SPECIFICATION
Year: 1883

page_text: LETTERS PATENT to Alexander Basil Wilson of Holywood in the County of
Down, Ireland and John Sturgeon of 3 Westminster Chambers Victoria Street
Westminster in the County of Middlesex Civil and Mechanical Engineers for
an Invention of "IMPROVEMENTS IN AND APPERTAINING TO MACHINERY FOR
COOLING ATMOSPHERIC AIR, PART OF 'WHICH INVENTION IS ALSO APPLICABLE
TO MACHINERY FOR COMPRESSING AIR
PROVISIONAL SPECIFICATION left by the said Alexander Basil Wilson and
John Sturgeon at the Office of the Commissioners of Patents on the
6th January 1883.
'
ALEXANDER BASIL WILSON of Holywood in the County of Down Ireland and
JOHN STURGEON of 3 Westminster Chambers Victoria Street Westminster in tho
"IMPROVEMENTS IN AND
County of Middlesex Civil and Mechanical Engineer
APPERTAINING TO MACHINERY FOR COOLING ATMOSPHERIC AIR, PART OF WHICH
INVENTION IS ALSO APPLICABLE TO MACHINERY FOR COMPRESSING AIR"
Our invention relates to that class of machinery for the cooling of air or gaseous
fluid in which the cooling effect is produced by the compression of same and its
re-expansion in the performance of work.
The first part of our invention relates to an improved arrangement of the
air compressing portion of a Cold Air Machine and is also applicable to air
compressing engines generally. In order to cool the air during compression it is
usual to surround the air compressing cylinders with a casing or jacket containing
water. But owing to the thickness of the metal of the air cylinder this cooling
action only partially affects that portion of the air immediately in contact with its
inner surface while the main body of air within the cylinder retains most of the
heat developed during compression and considerably increases the working load
against the piston. This remaining heat is usually got rid of, in cold air machines;
In order to enable us to get
by passing the air through tubes immersed in water
rid of this heat of compression, or of most of it during compression instead of after

page_text: By this
compression, instead of employing one large cylinder in which the air is compressod,
we employ a number of tubes immersed in water, in which tubes the air is
compressed by means of a number of rams or plungers working therein.
means the conducting surface is largely increased and at the same time conduction
greatly facilitated by the great reduction effected in the thickness of the metal,
while the cooling water is applied to smaller bodies of air enabling it to carry off
the heat of compression more effectively during the process of compression and
thus greatly reducing the load against the piston
Another mode of effecting this object is to employ one or more compressing
cylinders of annular form immersed in water with annular pistons working therein,
a free circulation of water being maintained both inside and outside.-By this
means a thin body of air is exposed to the action of the cooling water on two sides
instead of a thick body cooled on the outside as formerly.
The next part of our invention relates to improvements in and connected with
the expansion cylinder of cold air machines Heretoforo it has been usual in such
machines to employ an air compressing cylinder and an air expansion cylinder
geared or connected together so that the air expanding in the expansion cylinder
assists the work of the main driving cylinder in compressing the air. The objection
to this arrangement is the difficulty in regulating the exact proportions of the
capacity of the compressing and expanding cylinders (which proportion varies
with the different conditions of heat and moisture present in the atmospheric air
and the temperature and quantity of the cooling water) so that the air in the
expansion cylinder shall not be expanded below the atmospheric line, as would be
the case if the expansion cylinders were too large or not sufficiently expanded, as
would be the case if the expansion cylinders were too small.
In order to obviate this objection and at the same time to simplify the
working parts by dispensing with the levers rods, eccentrics and other parts
bitherto necessary in cold air machines, we make the exhaust valvo of the expansion
cylinder to open inwards by the action of a spring counterweight or other
equivalent contrivance sufficiently powerful to open the valve against the internal
pressure of the air in the expanding cylinder, only when it has reached such a
predetermined difference between the internal pressure and the discharged cooled
air as the spring may be set for. The exhaust valve is thus held shut by the
internal pressure of the expanding air until it has become sufficiently expanded at
which point (which may be earlier or later in the stroke according to the quantity
of air supplied from the compression cylinder or cylinders) the spring automatically
opens the valve against the reduced internal pressure and allows the remainder of
the stroke to be completed without that undue expansion of the air which is found in
other methods. This also ensures the more effective expansion of the air down to
the predetermined point.-During the return or inward stroke the spring holds
the valve full open allowing the cooled expanded air to pass out. On reaching the
end of the inward stroke the valve is closed by a tappet or other convenient
means, before admission of a fresh charge of compressed air, which keeps it shut
against the spring, and in the next stroke the action is repeated.
In addition to the exhaust valve above described we apply in some cases a valve
communicating with the outer air and so arranged that it will be caused to open
as soon as the air is expanded down to atmospheric pressure, so that during the
remainder of the stroke, the outer air may be admitted, and partly mixed with or
floated on the expanded cold air, the whole being expelled during the forward
stroke into the cold chamber.-By these means we avoid the partial vacuum at the
end of the stroke common to other methods where the expansion cylinder is too
large, and we minimise the formation of snow in the expansion cylinder and
outlet valve by taking into the expansion cylinder at a point furthest away from
the outlet valve a body or load of uncooled air which is last to be expelled and
which after being expelled fills or partly fills, the outlet pipe remaining there
until the outlet valve is next open, the cooled air practically never being allowed
to remain stationary in that part of the outlet pipe next the outlet valve.-We

page_text: also by this means deliver into the cold air chamber a larger body of air cooled to
a less degree which in some cases is desirable
In order to ensure the expansion cylinder receiving automatically a charge of
compressed air proportionate to the volume supplied by the compressing cylinder
or cylinders at or near their full pressure and to ensure a sharp cut off at the corre-
sponding point in the stroke we so arrange the admission valve as to make its
action dependent upon the pressure attained in the compression cylinder or cylinders
For this purpose we apply an admission valve so arranged that when once opened,
by tappet or other suitable contrivance it is retained open by the pressure of com-
pressed air admitted into the cylinder acting on one side of the valve against the
pressure of the atmosphere assisted by a spring, weight or other equivalent contri-
vance acting in the opposite direction; that is to say, tending to close it,-until
the advance of the expansion piston has sufficiently diminished the internal air
pressure as opposed to the atmosphere and spring to enable them to close the valve
from which point the air thus trapped into the expansion cylinder continues to
expand against the piston until the point is reached at which the exhaust valve
opens, as already described.-Or we may regulate the amount of air admitted into
the expansion cylinder by the difference in pressure between the air in the com-
pressed air reservoir and the atmosphere determining the position of a link or
other equivalent motion for regulating the admission valve. In these arrangements
it is advisable to have the reservoir space or chamber of compressed air of limited
capacity. To enable this principle of admission to be applied where the compressed
air reservoir is so largo that the advance of the expansion piston would not lower
the pressure sufficiently to ensure an accurate cut off, wo arrange a double valve
comprising a main and secondary valve communicating with the compressed air
reservoir so arranged as to trap in between the two valves a measured charge of
compressed air the amount of which is determined by the difference in pressure
between the compressed air and the atmosphere.
In connection with this arrangement we make each opening of the admission
valve to actuate mechanism so arranged as to drain off the water discharged from
the air by compression at each stroke.-We also arrange the exhaust valve or valves
50 ns to discharge the cold expanded air through the centre of the admission valve,
or through some portion of the compressed air reservoir, theroby keeping the
discharge passages sufficiently warm to prevent their becoming blocked up with ico,
the cold thus parted with being recovered in the reduced temperature of the com-
pressed air before entering the expansion cylinder.
According to another part of our invention we place the air compressing cylinders
vertically so that the weight of the pistons in descending assists the compression of
the air and we place the delivery valves at the bottom covering the whole area of
cylinder By this arrangement the lubricant is spread more evenly over the
surface than in the horizontal arrangement and it naturally descends so as to
lubricate the lower portion of the cylinder where the highest compression is reached
and the greatest heat generated and where lubrication is therefore most needed,
and by passing evenly over the valve face tends to prevent leakage of the air-
The inlet valves we place in the ends of vertical plunger-pistons working into the
air cylinders so that they may open by gravity during the upward stroke to admit
the air to the cylinders and close by the pressure of air against them in the
descending stroke. We also so arrange the expansion cylinder by preference
vertically that the work of raising the weight of the pistons, crossheads and other
vertically moving parts may be effected by the expansion cylinder the surplus
power of which, if any may be stored up in the flywheel and assist the compression
and we apply a valve or other suitable means to the driving steam cylinder so
arranged as to cut off the steam from the lifting side of the steam cylinder, opening
it to the exhaust; and to reduce the pressure on the acting side in proportion to
the power obtained from the expansion cylinder.
We also actuate the valve or valves of the steam engine driving the machine, by
mechanism connected with the valve moving mechanism of the expansion cylinder―

page_text: This arrangement enables us to work the machine either with crank and fly
wheel, or direct acting without crank and fly wheel as may in some cases bo
desirable. For the purpose of starting the apparatus we apply means to work
either the main or a supplementary valve on the steam cylinder by hand
To prevent leakage of air and at the same time avoid gland friction in the com-
pression and expansion cylinders, instead of or in addition to the ordinary gland or
stuffing box, we cover the end of the cylinder through which the piston rod or ram
works with a canvas india-rubber, leather or other casing of bellows-like form,
one end being fastened to the piston rod or ram and the other to the end of the
cylinder in which it works, so that as the piston rod or ram moves to and fro the
bellows-like casing may collapse or extend to allow of the motion
Another part of our Invention relates to the more effectual cooling of the air
'before admission into the expansion cylinder-For this purpose, we fill the reservoir
already referred to with tubes through which a circulation of water is maintained
O as to abstract any remaining heat from the compressed air after it has passed
from the compressing cylinders, and we so place this reservoir with regard to the
expanding cylinder that the latter may receive its charge of compressed air direct
from the lowest part of such reservoir where the coldest portion of the compressed
air and so that no direct current of uncooled air can flow from the compressing to
the expanding cylinder-We also surround the expansion cylinder with a casing
filled with brine, or non-freezing solution and communicating with a tube or tubes
or other equivalent arrangement situated in the said reservoir-By this arrange-
ment the casing containing the brine solution will at one part be in contact with
air at a lower temperature than at another part, thus maintaining a constant circu-
lation, while the cold thus imparted to the compressed air will be recovered in the
reduced temperature of the air on entering the expansion cylinder
Another part of our invention relates to the abstraction of moisture from the air
so as to reduce the formation of ice or snow-To effect this object we avail
ourselves of the scientific fact that moisture from the atmosphere collects more
readily on sharp edges and points than upon flat or smooth surfaces as is shown by
the ice collecting on grass the hoar frost on leaves, on rough surfaces, and on the
sharp edges of wood and iron work &c.-In applying this principle according to
our invention we cause the air, before entering the compressing and expanding
cylinders to pass over jagged and serrated surfaces or through a chamber or
chambers pipe or pipes the interior surfaces of which are rough and serrated or
filled with tubes rough or serrated, on their outsides, and having water or brine
solution circulating within or otherwise fitted with pointed serrated jagged or
roughened or crystalised surfaces, so as to collect the moisture from the air upon
such surfaces over or through which the air is made to pass before reaching the
expansion cylinder
-
In order to avoid loss of cold by reason of long conducting pipes and radiation
from the expansion cylinder and to obtain a greater degree of cold by supplying
the suppressed cylinder with already cooled air we so arrange the machine that the
compressing and expanding cylinders may be worked inside the insulated and
refrigerated chamber and driven by a steam cylinder outside the chamber and
connected to the compressing and expanding cylinders by a rod or rods passing
through packed openings in the insulated wall of the cold chamber
According to another part of our invention where the steam used for supplying
the power is of low pressure and saturated, we cool the compressed air and reinove
the moisture from the steam by passing the hot compressed air over surfaces
cooled below the temperature of the compressed air by the incoming steam-For
this purpose we compress the air sufficiently to generate a higher temperature than
that of the steam.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Basil Wilson and John Sturgeon in the Great Seal
Patent Office on the 6th July 1883.
ALEXANDER BASIL WILSON of Holywood in the County of Down, Ireland, and
JOHN STURGEON of three Westminster Chambers, Victoria Street, Westminster in
the County of Middlesex IMPROVEMENTS IN AND APPERTAINING TO MACHINERY
FOR COOLING ATMOSPHERIC AIR, PART OF WHICH INVENTION IS ALSO APPLICABLE
TO MACHINERY FOR COMPRESSING AIR
Our invention relates to that class of machinery for the cooling of air or gaseous
fluid in which the cooling effect is produced by the compression of same and its
re-expansion in the performance of work.
The first part of our invention relates to an improved arrangement of the air
coin pressing portion of a cold air machine, and is also applicable to air compressing
engines generally. In order to cool the air during compression it is usual to
surround the air compressing cylinders with a casing or jacket containing water.
But owing to the thickness of the metal of the air cylinder this cooling action only
partially affects that portion of the air immediately in contact with its inner
surface, while the main body of air within the cylinder retains most of the heat
developed during compression, and considerably increases the working load against
the piston. This remaining heat is usually got rid of in cold air machines by
passing the air through tubes immersed in water. In order to enable us to get rid
of this heat of compression, or of most of it, during compression instead of after
compression,-in place of each large air compressing cylinder such as is usually
employed, we employ a number of small tubes, of total equivalent area, immersed
in water, in which tubes the air is compressed by means of a number of rams or
plungers working therein. Fig. 1 of the accompanying drawing shows an elevation,
partly in section, of a cold air machine arranged in accordance with our invention.
A, A, are the rams or plungers, attached to the rim of a circular crosshead B, B,
carrying the expansion piston or ram in its centre, and C, C, are the tubes or
cylinders within which the plungers A, A work, the tubes C being surrounded
with water contained in the casing D ;-and, being of thin brass or other suitable
material, which their small size allows of without diminishing their strength, a
more rapid and effective conduction of the heat of compression is obtained than is
possible with the ordinary cylinders of thick metal. By this means, also, the
conducting surface is largely increased, while the cooling water is applied to
smaller bodies of air, enabling it to carry of the heat of compression more
effectively during the process of compression, and thus greatly reducing the load
against the piston.
Another inode of effecting this object is to employ one or more compressing
cylinders of annular form, immersed in water, with annular pistons working
therein, a free circulation of water being maintained both inside and outside. By
this means a thin body of air is exposed to the action of the cooling water on two
sides, instead of a thick body cooled on the outside only, as formerly. The cross
section in Fig. 1 will serve to represent this arrangement, by assuming the inner
side, a, of the tube C to represent a complete cylinder surrounding the expansion
cylinder E, and the outer side, a³, as another complete cylinder,-the annular space
In this
between being filled by A, representing an annular plunger or ram.
arrangement the valves, as shown, might be annular, or might consist of a number
of small circular valves. In the latter case a passage may be formed between any
two of the air delivery valves leading from the inner to the outer water casing, to

page_text: allow of free circulation of the water, the end of the plunger being recessed so as
to clear the casing of such water passage. Successive concentric annular cylinders
may be arranged in the above manner.
Tho
The next part of our invention relates to improvements in and connected with
the expansion cylinder of cold air machines. Heretofore it has been usual in such
machines to employ an air compressing cylinder and an air expansion cylinder,
geared or connected together, so that the air expanding in the expansion cylinder
assists the work of the main driving cylinder in compressing the air.
objection to this arrangement is the difficulty in regulating the exact proportions
of the capacity of the compressing and expanding cylinders,-(which proportion 1
varies with the different conditions of heat and moisture present in the atmospheric
air, and the temperature and quantity of the cooling water,)-so that the air in the
expansion cylinder shall not be expanded below the atmospheric line, as would be
the case if the expansion cylinder were too large, or not sufficiently expanded, as
would be the case if the expansion cylinder were too small.
In order to obviate this objection, and at the same time to simplify the working
parts by dispensing with the levers, rods, eccentrics and other parts hitherto
necessary for working the valves of the expansion cylinders in cold air machines,
we make the valves to open and close automatically by means of the variation in
pressure of the compressed air itself, inside and outside of the expansion cylinder. 2
This principle of working the valves we find to be most conveniently applicable in
connection with lift valves, although applicable also to slide valves. Thus, we
make the exhaust valve of the expansion cylinder to open inwards by the action
of a spring, counterweight, or other equivalent contrivance sufficiently powerful, to
open the valve against the internal pressure of the air in the expansion cylinder, 2
only when it has reached such a predetermined difference between the internal
pressure and the discharged cooled air as the spring may be set for. The exhaust
valve is thus held shut by the internal pressure of the expanding air, until it has
become sufficiently expanded, at which point, (which may be earlier or later in the
stroke according to the quantity of air supplied from the compression cylinder or 3
cylinders) the spring automatically opens the valve against the reduced internal
pressure, and allows the remainder of the stroke to be completed without that
undue expansion of the air which is found in other methods. This also ensures
the more effective expansion of the air down to the predetermined point. During
the return or inward stroke the spring holds the valve full open, allowing the 3
cooled expanded air to pass out. On reaching the end of the inward stroke the
valve is closed by a tappet or other equivalent contrivance before admission of a
fresh charge of compressed air, which keeps it shut against the spring, and in the
next stroke the action is repeated.
This arrangement is shown at E, Fig. 1 of the drawing. F is the exhaust valvo 4
referred to, resting upon the spring G, which tends to lift it off its seat. As the
piston H descends it drives the expanded cold air out through the valve F which
is held open by the spring G until the piston H reaches the end of its stroke,
where it comes in contact with the open valve and presses it up to its seat, thus
closing it, and at the same time forcing open the admission valve I, and admitting 4
compressed air into the cylinder. The pressure of the air thus admitted holds the
valve F to its seat, against the force of the spring, until the compressed air, by the
advance of the piston in its upward stroke, becomes sufficiently expanded and
reduced in pressure to enable the spring to lift the valve off its seat. The strength
of the spring G should be so regulated as to allow the air to be expanded as near 5
as possible to atmospheric pressure before the valve Fopens. On the opening of
the valve the expanded cooled air passes out through the hollow stem of the
admission valve I into the snow box J, and is thence conveyed to the chamber to
be cooled, or it may pass direct into the chamber.
In addition to the exhaust valve above described, we apply, in some cases, 5
a valve communicating with the outer air, and so arranged that it can be caused to
open as soon as the air in the expansion cylinder is expanded down to atmospheric

page_text: pressure, so that during the remainder of the stroke, if any, the outer air may
be admitted; and partly mixed with or floated on the expanded cold air, the
whole being expelled during the forward stroke into the cold chamber. By these
means we avoid the partial vacuum at the end of the stroke common to other
methods where the expansion cylinder is too large. We also so place this valve,
in connection with a vertical expansion cylinder, as to operate at or near the top
of the cylinder, so as to minimise the formation of snow in the expansion cylinder
and outlet valve, by taking into the expansion cylinder at a point furthest away
from the outlet valve, a body or load of uncooled air, which is last to be expelled,
and which, after being expelled, fills or partly fills the outlet pipe, remaining there
till the outlet valvo is next opened, the cooled air practically never being allowed
to remain stationary in that part of the outlet pipe next the outlet valve. We also
by this means deliver into the cold air chamber a larger body of air cooled to a
less degree, which in some cases is desirable. In Fig. 1 of the drawing this valve
is shown at K, in the head of the piston H, and is held up to its seat and thus kept
closed by the internal air pressure so long as any remains in the cylinder. Wnen
the pressure is exhausted the valve opens as described.
In order to ensure the expansion cylinder receiving automatically a charge
of compressed air proportionate to the volume supplied by the compressing cylinder
or cylinders at or near their full pressure, and to ensure a sharp cut off at the
corresponding point in the stroke, we so arrange the admission valve as to make its
action dependent upon the pressure of air produced by the compression cylinder or
cylinders. For this purpose we apply an admission valve so arranged that when
once opened, by tappet or other suitable contrivance, it is retained open by the
pressure of the compressed air admitted into the cylinder acting on one side of the
valve against the pressure of the atmosphere assisted by a spring weight or other
suitable contrivance acting in the opposite direction, that is to say, tending to
close it, until the advance of the expansion piston has sufficiently diminished the
internal air pressure as opposed to the atmosphere and spring to enable them to
close the valve, from which point the air thus trapped into the expansion cylinder
continues to expand against the piston until the point is reached at which the
exhaust valve opens, as already described. This arrangement of admission valve is
shown at 1, Fig. 1. The piston H on arriving at the end of its stroke comes in
contact with the valve I, and forces it off its seat, admitting compressed air from
the chamber or passage L into the expansion cylinder E. Should the air in the
passage L have attained sufficient pressure to resist the force of the spring M
applied through the lever N, it will hold the valve open, until the upward travel
of the piston shall have reduced the pressure below that necessary to withstand
the spring, whereupon the valve will close and the air thus shut into the cylinder
will expand against the piston during the remainder of the stroke. Should the air
not have reached sufficient pressure to withstand the spring, the valve I will return
to its seat as the piston rises, thus preventing any compressed air from being
carried away from the reservoir or passage L, and this action will be repeated until
sufficient strokes have been made by the compressing rams to charge up the passage
or reservoir to the required pressure.
In these arrangements it is advisable to have the reservoir space or chamber of
compressed air of limited capacity. To enable this principle of admission to be
applied where the compressed air reservoir is so large that the advance of the
expansion piston would not lower the pressure sufficiently to ensure an accurate
cut off, we arrange a double valve, comprising a main and secondary valve com-
municating with the compressed air reservoir, so arranged as to trap in between
the two valves a measured charge of compressed air of sufficiently limited volume
to enable the expansion piston by its travel to lower the pressure sensibly below
that necessary to counteract the spring. The action will then be the same as above
described. This arrangement is shown in Fig. 2, in which I is the admission valve
as before, and O the secondary valve carried on the stem of the valve I, and so
arranged that when the latter is opened the secondary valve O covers the ports P

page_text: communicating with the compressed air reservoir, and thus encloses in the space
beneath the valve I a limited quantity of compressed air, which, being shut off
from the reservoir, will be lowered in pressure by the upward travel of the piston
sufficiently to allow the force of the spring to close the valve. When the valve I is
closed the ports P are open, allowing the space underneath the valve to fill up
again with compressed air from the reservoir.
In this Fig. the stem of the valve I is shown working through an ordinary
stuffing box. In order to avoid the friction of a stuffing box, which is very variable
and would therefore tend to make the action of the spring and lever unreliable, we
employ a flexible diaphragm composed of a number of segments of spring-steel
plates placed close together so as to-form a complete disc with a circular opening in
the centre for the stein of the valve to pass through, a collar on the latter supporting
it upon the segments. These segments are shown at Q, Fig. 1, and may be
strengthened by one or more other sets underneath. In order to prevent the escape
of the air the whole are covered over by a thin disc R of sheet tin or other suitable
material, the whole thus making a closed air tight diaphragm sufficiently flexiblo
to allow of the play of the valve, and the resistance of which is constant and not
variable as is the case with the friction from an ordinary gland stuffing box.
We may also regulate the amount of air admitted into the expansion cylinder in
a cold air machine by the difference in pressure between the air in the compressed
nir reservoir or passage and the atmosphere determining the position of a link or
other equivalent motion for regulating the admission valve. One mode of carrying
out this arrangement, applicable to cold air machines in which the expansion
cylinder is worked with valves of ordinary type, is shown in Fig. 3,-where S
represents a portion of the compressed air reservoir communicating direct with the
Bmall cylinder T, containing a piston U, coupled by a rod V to the link W. The
piston U is pressed downwards by a spring. When the air pressure in the
reservoir S rises, it forces up the piston U against the spring and raises the link W,
and when the pressure lowers the spring forces the piston down and lowers the
link. Through the link W the cut off valve is actuated in the ordinary way.
In connection with the arrangements shown in Figs. 1 and 2 we may make each
opening of the admission valve to actuate a small drain valve for the purpose of
draining off the water discharged from the air by compression at each stroke.
We also arrange the exhaust valve or valves so as to discharge the cold expanded
air through the centre of the admission valve, or through some portion of tho
compressed air reservoir, thereby keeping the discharge passages sufficiently warm
to prevent their becoming blocked up with ice, the cold thus parted with being
recovered in the reduced temperature of the compressed air before entering the
expansion cylinder,-as shown at E, Fig. 1.
According to another part of our invention we place the air compressing
cylinders vertically, as shown at A and C, Fig. 1, so that the weight of the pistons
in descending assists the compression of the air;-and we place the delivery
valves, shown at X, Fig. 1, and enlarged in Fig. 4,-nt the bottom covering the
whole area of the cylinder. By this arrangement the lubricant is spread more
evenly over the surface than in the horizontal arrangement, and it naturally
descends so as to lubricate the lower portion of the cylinder, where the highest
compression is reached and the greatest heat generated, and where lubrication is
therefore most needed-and by passing evenly over the valve face tends to prevent
leakage of the air. The inlet valve Y,-shown enlarged in Fig. 4,-
-we place in
the ends of the vertical plunger pistons A, working into the air cylinders C, so
that they may open by gravity during the upward stroke, to admit the free air to
the cylinders, and close by the pressure of air against them in the descending
stroke.
We also so arrange the expansion cylinder, by preferenco vertically, that the
work of raising the weight of the pistons, crossheads, and other vertically moving
parts may be effected mainly by the expansion cylinder, the surplus power of

page_text: which, if any, may be stored up in the fly wheel and assist the compression ;-as
shown in Fig. 1.
We also actuate the valve or valves of the steam engine driving the machine by
mechanism connected with the valve moving mechanism of the expansion cylinder.
This arrangement enables us to work the machine either with crank and fly wheel
or direct acting without crank and fly wheel, as may in some cases be desirable.
This may be effected by connecting a lever to the stem of the valve I, through
which the movement of the latter may be transmitted by a rod to the valve
spindle of the engine Z, Fig. 1, the motion on the upward stroke, in which the
valve I reverses before the piston completes its stroke, being regulated by cataract
or other commonly known method. For the purpose of starting the apparatus we
apply means to work either the main or a supplementary valve, on the steam
cylinder, by hand.
To prevent leakage of air and at the same time avoid gland friction in tho
compression and expansion cylinders, instead of the ordinary gland or stuffing box,
we cover the end of the cylinder through which the piston rod or ram works, with
a canvas, india rubber, leather or other casing of bellows-like form, one end being
fastened to the piston rod or ram, and the other to the end of the cylinder in
which it works, so that, as the piston rod or ram moves to and fro, the bellows
like casing may collapse or extend to allow of the motion.
Another part of our invention relates to the more effectual cooling of the air
before admission into the expansion cylinder. For this purpose we fill the
reservoir or passage L already referred to with tubes, as shown, through which a
circulation of water is maintained, so as to abstract any remaining heat from the
compressed air after it has passed from the compressing cylinders, and we so place
this reservoir or passage with regard to the expanding cylinder, that the latter may
receive its charge of compressed air direct from the lowest part of such reservoir,
where the coldest portion of the compressed air is found, and so that no direct
current of uncooled air can flow from the compressing to the expanding cylinder,―
as shown at L, Fig 1.
We also surround the expansion cylinder with a casing filled with brine or non
freezing solution, and communicating with a tube or tubes or other equivalent
contrivance situated in the compressed air reservoir or passage. By this arrange-
inent the casing containing the brine solution will at one part be in contact with
air at a lower temperature than at another part, thus maintaining a constant
circulation, while the cold thus imparted to the compressed air will be recovered
in the reduced temperature of the air on entering the expansion cylinder.
Another part of our invention relates to the abstraction of inoisture from the
air so as to reduce the formation of ice or snow. To effect this object we avail
ourselves of the scientific fact that moisture. from the atmosphere collects more
readily on sharp edges and points than upon flat or smooth surfaces,-as is shown
by the ico collecting on grass, the hoar frost on leaves, on rough surfaces, and on
the sharp edges of wood and iron work &c. In applying this principle according
to our invention, the chamber or chambers, pipe or pipes, through or over which
the air passes have their surfaces rough serrated or crystalline on the side exposed
to the air, such surfaces being kept cool by having water or brine solution
circulating over the other side thereof, or otherwise provided with pointed,
serrated, jagged, roughened or crystalline surfaces, so as to collect the moisture
from the air upon such surfaces, over or through which the air is made to pass
before reaching the expansion cylinder.
In order to avoid loss of cold by reason of long conducting pipes and radiation
from the expansion cylinder, and to obtain a greater degree of cold by supplying
the compressing cylinder with already cooled air, wo so arrange the machine that
the compressing and expanding cylinders may be worked inside the insulated
cooling chamber, and driven by a steam cylinder outside the chamber and con-
nected to the compressing and expanding cylinders by a rod or rods passing
through packed openings in the insulated wall, floor or ceiling of the cooling

page_text: chamber. This may be readily understood by assuming the engine Z, Fig. 1, to
be fixed above the ceiling of the cooling room, such ceiling forming the partition
between the engine room and the cold air chamber below, within which the cold
air machine proper is fixed.
According to another part of our invention where the steam used for supplying
the power is of low pressure and saturated, we cool the compressed air and remove
the inoisture from the steam by passing the hot compressed air over surfaces cooled
below the temperature of the compressed air by the incoming steam. For this
purpose we compress the.air.sufficiently to generate a higher temperature than
that of the steam.
Having thus described our invention and shown by the drawing annexed one
mode of practically carrying it out, wo would have it clearly understood that we do
not confine ourselves to the precise methods strewn and described, as the same
may be in many ways modified in detail while still retaining the principles and
the characteristic features of our invention, but we claim as our invention the
improvements relating to cold air machinery substantially as set forth, illustrated,
or described herein, whether separately or in combination, together with the
application to engines used only for compressing air, of those portions of the herein
described improvements relating to the air compressing portion of cold air
machines as are applicable thereto.
In witness whereof, we, the said Alexander Basil Wilson and John Sturgeon,
have hereunto set our bands and scals, this fifth day of July, in the year
of our Lord One thousand eight hundred and eighty three