IMPROVEMENTS IN AIR- REFRIGERATING APPARATUS
Year: 1882

page_text: LETTERS PATENT to Thomas Bell Lightfoot, of No. 116, Fenchurch Stroet,
in the City of London, for an Invention of "IMPROVEMENTS IN AIR-
REFRIGERATING APPARATUS."
PROVISIONAL SPECIFICATION left by the said Thomas Bell Lightfoot at
the Office of the Commissioners of Patents on the 11th February 1882.
THOMAS BELL LIGHTFOOT of No. 116, Fenchurch Street in the City of London.
"IMPROVEMENTS IN AIR REFRIGERATING APPARATUS."
My Invention relates to the construction and arrangement in simple and compact
form of machines for refrigerating by compressing and cooling air and then
expanding it while it performs work. On a hollow base containing tubes through
which water circulates, I mount in bearings a crank-shaft carrying a fly and driving
pulley; to the crank I connect the rod of a double piston working in a cylinder the
front part of which is larger than the hinder part. At each end of the cylinder on
each side thereof I provide valves which are conveniently made like stop cocks and
which are worked by eccentrics or cams on the crankshaft. The machine being
driven by a belt from any suitable motor, air is drawn into the front part of the
cylinder and being compressed therein it is discharged into the hollow base where
it is cooled by contact with the water tubes. The cooled compressed air then
enters the hinder part of the cylinder where it expands assisting the piston in its
forward stroke, and becoming greatly reduced in temperature it is discharged and
conveyed by a pipe to the chamber or locality where the cold air is required.
Instead of driving the machine by a belt, its shaft may be coupled to the shaft of a
steam or other fluid pressure engine so as to be worked thereby directly.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Bell Lightfoot in the Great Seal Patent Office on the
10th August 1882.
THOMAS BELL LIGHTFOOT of No. 116 Fenchurch Street in the City of London.
"IMPROVEMENTS IN AIR REFRIGERATING APPARATUS."
My Invention relates to the construction and arrangement in simple and compact
form of machines for refrigerating by compressing and cooling air and then
expanding it while it perforins work. On a hollow base containing tubes through
which water circulates, I mount in bearings a crank shaft carrying a fly-wheel and
driving pulley; to the crank I connect the rod of a double piston working in a
cylinder, the front part of which is larger than the hinder part. At each end of
the cylinder on each side thereof I provide valves which are conveniently made
like stop cocks and which are worked 'by eccentrics or cams on the crank shaft.
The machine being driven by a belt from any suitable motor, air is drawn into the
front part of the cylinder and being compressed therein it is discharged into tho
hollow base where it is cooled by contact with the water tubes. The cooled com-
pressed air then enters the hinder part of the cylinder where it expands assisting
the piston in its forward stroke, and becoming greatly reduced in temperature it is
discharged and conveyed by a pipe to the chamber or locality where the coold air
is required. Instead of driving the machine by a belt, its shaft may be coupled to
the shaft of a steam or other fluid pressure engine so as to be worked thereby
-directly.-
Fig 1 of the accompanying Drawings is a side view partly in section-and-Fig-2
is a plan of an air refrigerating apparatus according to my Invention. A is the
air compressing pump which takes in air through the cock a¹ and discharges it com-
pressed through the cock a² and pipe B into the hollow foundation C through which
cooling water circulates in tubes D. Behind the pump A and in the same line
with it is the expansion cylinder E which receives the cooled compressed air from C
by the pipe F and through the cock e. The air expands in the cylinder E
assisting the forward stroke of the piston and becoming refrigerated, and issues
through the cock e² and passes by the pipe G to the chamber in which the cold air
is employed. Both the pistons of A and E are connected by a connecting rod to a
crank on the fly-wheel shaft H which may be driven by a belt or otherwise from
any suitable inotor. The cocks a a² e¹ e² are worked by eccentrics K on the
shaft H, these eccentrics being set so as to turn the opening and closing of the
cocks suitably to the movement of the pistons. It is obvious that instead of
cocks turning on their axes, slides might be employed, or valves worked by cams
on the shaft H.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I claim :—
The construction and arrangement of air refrigerating apparatus substantially
as herein described and illustrated by the accompanying Drawings.
In witness whereof I the said Thomas Bell Lightfoot have hereunto set my
hand and seal this Tenth day of August in the year of our Lord Ono
thousand eight hundred and eighty two.
m D LIGHTFOOT