IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR.”
Year: 1871

page_text: LETTERS PATENT to David Greig and William Daniel, both of the
Steam Plough Works, Leeds, in the County of York, for the
Invention of " IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR.”
PROVISIONAL SPECIFICATION left by the said David Greig and
William Daniel at the Office of the Commissioners of Patents, with
their Petition, on the 16th June 1871.
We, DAVID GREIG and WILLIAM DANIEL, both of the Steam Plough
Works, Leeds, in the County of York, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR,"
to be as follows:-
This Invention has for its object improvements in machinery for.
compressing air and consists in the employment of such an arrangement
of outlet or delivery valves from the cylinders of machinery for com-
pressing air that the piston working in the air cylinder can be caused to
travel the whole length of the cylinder between the covers without any
allowance for clearance, and by this means to force out the greatest
possible amount of air at each stroke. This is accomplished by making
the cylinder covers themselves the outlet valves, and allowing them to

page_text: open or move away from the ends of the cylinder sufficiently to pass the
compressed air into compressed air chambers. These air chambers are
cast on or bolted to each end of the cylinder and are connected one to
the other by a branch pipe. The cylinder covers, otherwise the outlet
valves, are connected to the front of the air chambers by a thin metal
plate fastened at its outer edge to the air chamber, and at its inner edge
to a projecting ring cast on the back of the cylinder cover. The metal
discs can be made either plain or corrugated, and they form a flexible
air-tight connection between the front of the air chambers and the rings
at the back of the cylinder covers and allow the cylinder covers to move
away sufficiently from the ends of the cylinders to permit the air com-
pressed in the cylinders to escape into the air chambers. To ensure a
rapid closing of the cylinder covers or outlet valves we apply springs
which can be fixed either inside or outside the air chambers. The piston
rods pass through stuffing boxes in the cylinder covers, and the inlet valves
for admitting air to the cylinder are by preference formed by a ring of
india-rubber covering a number of holes drilled through the cover.
In place of employing flexible metal discs to form an air-tight joint
between the cylinder covers and the front of the air chamber the ring
or trunk on the back of each cover or valve may be arranged to work
in a stuffing box formed at the front of the air chamber, and in this case
to overcome the friction of the stuffing box and also to ensure a rapid
closing of the valve we place springs between the cover of the air
chamber and the valve.
In order to keep the piston in the air cylinder in such a position that
it shall work to its proper distance at each end of the stroke we connect
the piston rod of the air cylinder to the piston rod or other part of
the steam engine by which it is driven by a nut having a right and left-
hand thread or by other adjustable coupling.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 3
filed by the said David Greig and William Daniel in the Great
Seal Patent Office on the 16th December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, DAVID
GREIG and WILLIAM DANIEL, both of the Steam Plough Works, Leeds,
in the County of York, send greeting.
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of June, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said David Greig and William Daniel, Her
special licence that we, the said David Greig and William Daniel, our
executors, administrators, and assigns, or such others as we, the said
David Greig and William Daniel, our 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 "IMPROVEMENTS IN MACHINERY FOR COM-
PRESSING AIR," upon the condition (amongst others) that we, the said
David Greig and William Daniel, our executors or administrators, by
an instrument in writing under our or their hands and seals, or under
the hand and seal of one of us or them, 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 imme.
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Daniel, on behalf of
myself and the said David Greig, 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 thereof, that is to say:—
This Invention has for its object improvements in machinery for
compressing air, and consists in the employment of such an arrangement
of outlet or delivery valves from the cylinders of machinery for com-
pressing air that the piston working in the air cylinder can be caused
to travel the whole length of the cylinder between the covers without
any allowance for clearance, and by this means to force out the greatest
possible amount of air at each stroke. This we accomplish by making
the cylinder covers themselves the outlet valves, and allowing them to
open or move away from the ends of the cylinder sufficiently to pass
the compressed air into compressed air chambers. These air chambers
are cast on or bolted to each end of the cylinder and are connected one
to the other by a branch pipe. The cylinder covers, otherwise the outlet

page_text: The metal
valves are connected to the front of the air chambers each by a thin metal
plate fastened at its outer edge to the air chamber, and at its inner edge
to a projecting ring cast on the back of the cylinder cover.
discs can be made either plain or corrugated, and they form a flexible
air-tight connection between the front of the air chambers and the
rings at the back of the cylinder covers, and allow the cylinder covers
to move away sufficiently from the ends of the cylinders to permit the air
· compressed in the cylinders to escape into the air chambers. To ensure
a rapid closing of the cylinder covers or outlet valves we apply springs
which can be fixed either inside or outside the air chambers. The piston
rods pass through stuffing boxes in the cylinder covers, and the inlet
valves for admitting air to the cylinder are by preference formed by
a ring of india-rubber covering a number of holes drilled through the
cover.
In place of employing flexible metal discs to form an air-tight joint
between the cylinder covers and the front of the air chamber the ring
or trunk on the back of each cover or valve may be arranged to work in
a stuffing box formed at the front of the air ehamber, and in this case
to overcome the friction of the stuffing box and also to ensure a rapid
closing of the valve we place springs between the cover of the air
chamber and the valve.
In order to keep the piston in the air cylinder in such a position that
it shall work to its proper distance at each end of the stroke we connect
the piston rod of the air cylinder to the piston rod or other part of the
steam engine by which it is driven by a nut having a right and left 1
hand thread or by other adjustable coupling.
In order that our said Invention may be most fully understood and
readily carried into effect, we will proceed to describe the Drawings
hereunto annexed.

page_text: are pressed by springs d. Three such springs are arranged at equal
distances apart around each cylinder cover; c³, c³, are trunks with which
in this arrangement the cylinder covers are furnished; they pass
through stuffing boxes e¹, e¹, on the ends of the air chambers e; f is a
passage connecting the air chamber e and from which by an outlet at f¹
the compressed air passes to the place where it is required for use;
9, 9, are the inlet valves; they are discs of vulcanised india-rubber
covering holes bored in the cylinder covers.
Figure 3 is a longitudinal section, and Figure 4 an end elevation of
apparatus similar to that already described, but for the trunks c³ and
stuffing boxes e¹ flexible metal discs h, h¹, are substituted, by preference,
we corrugate this disc, as is shewn at h¹, external blade springs d are
shown to take the place of the internal coiled springs in Figure 1. The
air inlets are also shown in Figure 5, which is a transverse section taken
on the line A, B, in Figure 3.
Having thus described the nature of our said Invention, and the
manner of performing the same, we would have it understood that we
claim the construction of machinery for compressing air in such manner
that the cylinder covers may operate as the outlet valves, substantially
as described.
We also claim the construction of machinery for compressing air,
substantially as described and shewn in the annexed Drawings.
In witness whereof, I, the said William Daniel, have hereunto set
my hand and seal, this Fourteenth day of December, in the year
of our Lord One thousand eight hundred and seventy-one.
T