MACHINES FOR PRODUCING COLD AIR."
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Everard Hesketh at the
Office of the Commissioners of Patents on the 15th September 1881.
EVERARD HESKETH, of Dartford, in the County of Kent.
MACHINES FOR PRODUCING COLD AIR."
"IMPROVEMENTS IN
This Invention has for its object improvements in machines for producing cold
air, and the improvements relate to machinery of that class in which air after
being compressed is allowed to expand in a cylinder to atmospheric pressure or
nearly so. In order to prevent the accumulation of snow in the expansion cylinder
I place the delivery valves through which the air is discharged after being
expanded at the end or ends of the cylinder, and I make the end or ends of the
cylinder to slope or converge towards the delivery valves, so that when the
delivery valves are opened for the expanded air to be delivered through them
all snow deposited in the cylinder is swept along and discharged through them.
The delivery valve may be either a slide, or a disc, or other form of valve; if a
dise valve is used its surface towards the piston of the cylinder should be of a
conical form.
In order to abstract the snow from the air after it has been discharged from the
cylinder I cause it to be discharged into a "snow box" in which the snow deposits
itself, and I adapt to this snow box an automatic arrangement for clearing the
snow from it. The snow extracted from the snow box may either be allowed to
thaw by the ordinary heat of the atmosphere, or it may be used to cool pipes
through which the compressed air passes before it enters the expansion cylinder.
I use a snow box of any convenient form, preferably circular, and I fit
within it scrapers worked by mechanism from the refrigerator. One method is to
employ arms revolving in a circular snow box, the arms being of a curved form to
make the snow accumulate at the periphery of the box. Along one side of this
box I make a recess, into which the snow is pushed by the arms, and from this it
[Price G1

page_text: is delivered by a revolving worm to the outside of the box. It may then fall into
a trough or other receptacle, through which pass the compressed air pipes on their
way to the expansion cylinder; or, as previously stated, the snow may be
allowed to melt by the natural heat of the atmosphere; in both cases it is run off
as water.
Another means of getting rid of the snow is to place in front of the exit from the
expansion cylinder an endless piece of wire gauze or other porous and flexible
material; this is made to travel by suitable mechanism from the refrigerator and
passes through roller in and out of the box into which the air exhausts. The wire
gauze or other material after passing out through the rollers is cleared of snow, and
passes in again at the other end.
The snow can be utilized or not as before.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Everard Hesketh in the Great Seal Patent Office on the 15th March
1882.
EVERARD HESKETH, of Dartford, in the County of Kent.
MACHINES FOR PRODUCING COLD AIR."
"IMPROVEMENTS IN
This Invention has for its object improvements in machines for producing cold
air. The improvements relate to machinery of the class in which air after being
compressed is allowed to expand to atmospheric pressure or nearly so. This
expansion is accompanied with the formation of a small amount of snow, and it is
important that this should be driven out of the cylinder of the machine at each
stroke of the piston.
With this object I place the delivery valve at the end of the cylinder, and make
the end to slope or converge to the aperture to which the valve is fitted.
If the cylinder be double acting it has a delivery valve at each of its ends.
Also in the snow box which is employed to collect the snow, and separate it
from the cold air after it leaves the cylinder, I provide automatic machinery to
remove the snow from the surfaces of the box and to deliver it continuously.
These improvements may be used separately or in combination.
And in order that my Invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a section of a part of the expansion cylinder with its cover or end
and delivery valve.
A is the portion of the expansion cylinder; in this a piston moves to and fro
doing work upon a crank on a shaft, which is also driven by steam or other power,
and from which compressing apparatus is worked to maintain the supply of
compressed air to the expansion cylinder. A' is the passage by which the air
enters the cylinder A. The admission valve closes at a prearranged point in the
stroke, and while the stroke is being completed the expansion takes place. B is
the cylinder end, and B₁ the outlet aperture in it to which the exit valve C is
fitted; B are the sloping surfaces in the cylinder end leading to the valve
aperture. The valve C represented in the Drawing is a disc valve, and this form
of valve is preferred, although other valves may be used. The inner face of the
valve C is slightly coned, so that the snow may be less liable to accumulate upon
it. The valve is opened and closed at the proper times by a cam or in any other
convenient manner. The cooled air passes away by the conduit D, first to the
SDOW box and then to the refrigerator or place where the cold air is utilized.
Figure 2 is a longitudinal section of the snow box with its automatic delivery
apparatus; Figure 3 is a plan; Figures 4 and 5 are end elevations partly in
section, and Figure 6 is a transverse section of the same.
In Figures 2, 3, 4, 5, and 6, A is the snow box arranged generally inside the
bed plate B of the machine. This snow box is of a circular form containing several
diaphragms, so arranged that the air has to pass by circuitous course out of the
box; H is the inlet and I the outlet pipe. The shaft C passes through the snow
box, and on it are fixed the scrapers D, D, D, &c. In a recess E below the snow
box is a continuous eanvas band F, which is supported on rollers G, G, at the ends.
Motion is given to the shaft C and one roller G by any convenient mechanism
worked from the moving parts of the machine.

page_text: As represented in the Drawing a reciprocating part of the machine actuates a
lever, L, carrying a pawl which takes into the teeth of a ratchet wheel in the
axis M.
There is a worm M¹ on this axis gearing with a worm wheel fixed on the
axis C, and there is also a pinion M2 which gears with a spur wheel G¹ on the axis
of one of the rollers G.
When the air from the expansion cylinder sur-charged with snow passes into
the snow box through pipe H the snow is intercepted by the diaphragm and
collects thereon. As the scrapers revolve the snow is dislodged from the surface
of the snowbox on which it had adhered, and is deposited in the recess in which
the continuous belt is travelling. This belt conveys the snow to one end of the
snowbox, at this end of the snowbox is a trough J, through which passes a pipe K
conveying the compressed air on its way to the expansion cylinder, heat from
which is absorbed by the snow, which is thereby melted, and resulting water is
allowed to run off by a water trap.
By the adaptation of automatic apparatus to the snow box, as above described,
I avoid the necessity of opening the snow box from time to time to empty it.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim, my improvements in
machines for producing cold air, substantially as herein described.
In witness whereof, I, the said Everard Hesketh, have hereunto set my hand
and seal, this Fifteenth day of March, in the year of our Lord One
thousand eight hundred and eighty two.
E. HESAETH, (LS)