Year: 1879

page_text: I WILLIAM HENRY NORTHCOTT 7 Saint Mary's Road Peckham, London S.E.
seek leave to amend the specification of Letters Patent, No. 1200 of 1879, as shown
in red ink in the copy of the original specification hereunto annexed:-
My reasons for making this amendment are as follows:-
A draughtsmans error has been made in Fig. 1 whilst Figs. 3 and 5 are of
little use.
August 12th, 1885,

page_text: DECISION.
Having leard Mr. Lloyd Wise as Agent for the Applicants and Mr. Aston as
Agent for the Opponent, I allow this Specification and the drawings forming part.
thereof to be amended in the manner shewn in the Blue Book hereunto annexed
marked "A" and initialled by me upon condition that no action for infringement
or other proceeding be taken by the said William Henry Northcott against the
said Frank Walter Scott or against any other person or persons in respect of any
machine or machines, or the use of any machine or machines, manufactured by the
said Opponent prior to the 21st day of April 1886.

page_text: LETTERS PATENT to William Henry Northcott, of 8, Union Court, Old Broad
Street, London, E.C., for the Invention of "IMPROVEMENTS IN MACHINERY OR
APPARATUS FOR COMPRESSING AIR AND OTHER GASES."
Sealed the 19th September 1879, and dated the 26th March 1879.
"
PROVISIONAL SPECIFICATION left by the said William Henry Northcott at
the Office of the Commissioners of Patents on the 26th March 1879.
WILLIAM HENRY NORTHCOTT, of 8, Union Court; Old Broad Street, London, E.C.
IMPROVEMENTS IN MACHINERY OR APPARATUS FOR COMPRESSING AIR AND OTHER
GASES."
C
In the construction of my improved machine for compressing air and gases gene-
rally I employ a main cylinder, the piston of which is prolonged to form a second
cylinder of smaller capacity. The air drawn into the main cylinder by the motion
of the main piston in one direction is forced into the smaller cylinder during the
return stroke, and is there further compressed by a stationary piston, upon which
the second cylinder works. Water is admitted with the air into the first cylinder
to lubricate and keep cool the interior parts, and with great increases of density or
quick compression, I also cool the air by passing it through a cooling coil between
the stages of the compression, also through another cooling coil after leaving the
final cylinder. I also surround the whole of the compressing apparatus and coils
with water, and maintain a constant circulation of cold water through this casing,
either by a separate water pump or other means of circulation, or by preference by
the moving piston acting as a water pump on one side, and an air pump on the
other. I prevent the engine racing when worked by means of steam by any form
of governor, but I prefer to make the pressure in the water chamber, which varies
with the speed of the pump, act on the steam valve. In some cases I employ two
or more of these compressors arranged side by side, the one delivering compressed
air to the other for further compression, and in other cases I arrange the com-
pressing cylinders the one inside the other, whereby I obtain four compression
stages in the same space as is occupied by a single cylinder,
t

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Northcott in the Great Seal Patent Office on the 25th
September 1879.
:
WILLIAM HENRY NORTHCOTT, late of 8, Union Court, Old Broad Street, London,
E.C., now of Hatcham Ironworks, Pomeroy Street, London, S.E. "IMPROVEMENTS
IN MACHINERY OR APPARATUS FOR COMPRESSING AIR, AND OTHER GASES."
..
My improvements in machines or apparatus for compressing air and other gases
refer mainly to those parts of the machinery directly employed in the compression
and not to the actuating or driving part. The construction of my improved
machinery is illustrated by a series of sectional views, numbered 1 to 6 3 in the
Sheet of Drawings appended hereto, and will be fully understood by the aid of the
following description
Figures 1 and 2 are two sectional elevations of one form of my compressor,
wherein a is the main cylinder, into which air or other gas is drawn at the valve b,
a spray of water being at the same time admitted through the channel c. The
piston d works within the cylinder a, and draws air into the cylinder by its upward
movement, the apparatus, as shown, being arranged to work vertically. The piston
rods, as in this case there are two, e, e, are attached to the piston d, and proceed
outwards through stuffing boxes f; f, to the crank or steam piston driving the com-
pressor. The air or other gas in the cylinder at the end of the upward stroke of
the piston d is on the down stroke of this piston forced through the valve g into a
smaller cylinder h. This cylinder is formed by a continuation upwards of the main
piston d. The piston i belonging to the cylinder h is stationary. When the
piston d is at the bottom of its stroke the air drawn into a has been wholly com-
pressed into the cylinder h, which has a smaller capacity than the first or main
cylinder a. On the next upward stroke of the main piston d' the valve g closes, a
fresh supply of air is drawn into the cylinder a, whilst the contents of h are expelled
through the valve k and cooling coil off to a reservoir or other receptacle at m.
These cylinders are so proportioned in size that the same maximum strain comes
upon each piston. Sometimes instead of admitting water at c I admit it by a
smaller valve at n opening into the air cylinder from the water chamber. The
main cylinder a is provided with a jacket o, through which a circulation of water
is maintained by means either of a separate pump or other ordinary means, but
preferably by the action of the apparatus itself, as will presently be described. The
small valve t'on the top of the cooling coil is an escape or safety valve. The cir-
culating or cooling water enters the jacket by the valve p, and passes through
holes q, q, to the inside of the cylinder a on the upper side of the piston d, and is
expelled through the valve r. Or the water may be drawn in at r and expelled at p,
or otherwise, the object being to bring a continuous supply of cold water into
contact with all the parts likely to rise in temperature in consequence of the com-
pression. The water circulation is effected without the aid of any separate pump

page_text: by the motion of the piston d, which alternately increases and decreases the
capacity of the water chamber after the manner of a pump. The downward
motion of the piston d causes water to flow into the water chamber through the
suction valve p, and its upward motion expels it through the valve r.
The actual
quantity drawn in is regulated by a cock on the suction, or other usual means.
8, 8, are pillars, whereby the air compressing cylinder is attached to the steam
cylinder or baseplate.
The compressor, as described, completes its work in two stages, but for very high
pressures the air delivered at m is conveyed into another compressor of similar con-
struction, and there further compressed.
In some cases I introduce a cooling coil between the cylinders a and h. This
coil receives the air from a valve situated similarly to the valve n, and delivers it
to another valve arranged in the same manner, but communicating with the cylin-
der h. Figure-3-shows-a-compressor-in-which-the-compression-of-the-air-or-other
gas is effected in-four stages. a is the main oylinder; b, its piston, the upward
motion-of-which-causes-air-to-flow-in-at-the-valve-c. On-the-downward-stroke-the
air-is-expelled-into the chamber d through the valve-e.--On-the-next-upward-stroke
the-air-is-expelled-through-the-valve-f-into-the-chamber-g,-and-on-the-next-down-
ward-stroke-the-air-in-g-is-expelled through the valve-h-into-the-inner-chamber-i,
thence-again-on-the-next-upward-stroke-through-the-valve-k-into-the-cooling-coil-l,
and-off-to-the-reservoir-at-m.--The-eireulating-water-is-drawn-in-at-n,-and-expelled
at-o-by-the-same-means-as-before.
Figure 4-shows-u-somewhat different-form-of-my-4-stage-compressor.--Air-drawn
into-a-is-compressed first-into-by-secondly-into-e-thirdly-into-d, and fourthly-inte
the-reservoir. The-cooling-water-is-eireulated-as-before.
In Figure 5-the-air-drawn into-a-is compressed into-by-then-into-c-and-again
into-the-reservoir-through-the-valve-d, this being-a-three-stage-compressor.
In Figure 63 the air or other gas with a slight admixture of water is drawn
through the valve a into the cylinder b. It is then compressed into the cylinder
or chamber c, then through the valve d and the cooling coil e into the chamber f,
then again into the reservoir through the cooling coil g, the compression in this case
also being effected in three stages. The cooling water is circulated by means of
a separate pump, or its equivalent.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is-
1. The stage compressor substantially as described and shewn in Figs. 1 and 2.
2. The three stage air compressor shewn at Fig. 3 and substantially as described.
In witness whereof, I, the said William Henry Northcott, have hereunto set
my hand and seal, this Twenty-fourth day of September, in the year of
One thousand right hundred and coments nine

page_text: LETTERS PATENT to William Henry Northcott, of 8, Union Court, Old Broad
Street, London, E.C., for the Invention of "IMPROVEMENTS IN MACHINERY OR
APPARATUS FOR COMPRESSING AIR AND OTHER GASES."
Sealed the 19th September 1879, and dated the 26th March 1879.
PROVISIONAL SPECIFICATION left by the said William Henry Northcott at
the Office of the Commissioners of Patents on the 26th March 1879.
WILLIAM HENRY NORTHCOTT, of 8, Union Court, Old Broad Street, London, E.C.
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR COMPRESSING AIR AND OTHER
GASES."
In the construction of my improved machine for compressing air and gases gene-
rally I employ a main cylinder, the piston of which is prolonged to form a second
cylinder of smaller capacity. The air drawn into the main cylinder by the motion
of the main piston in one direction is forced into the smaller cylinder during the
return stroke, and is there further compressed by a stationary piston, upon which
the second cylinder works. Water is admitted with the air into the first cylinder
to lubricate and keep cool the interior parts, and with great increases of density or
quick compression. I also cool the air by passing it through a cooling coil between
the stages of the compression, also through another cooling coil after leaving the
final cylinder. I also surround the whole of the compressing apparatus and coils
with water, and maintain a constant circulation of cold water through this casing,
either by a separate water pump or other means of circulation, or by preference by
the moving piston acting as a water pump on one side, and an air pump on the
other. I prevent the engine racing when worked by means of steam by any form
of governor, but I prefer to make the pressure in the water chamber, which varies.
with the speed of the pump, act on the steam valve. In some cases I employ two
or more of these compressors arranged side by side, the one delivering compressed
air to the other for further compression, and in other cases I arrange the com-
pressing cylinders the one inside the other, whereby I obtain four compression
stages in the same space as is occupied by a single cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Northcott in the Great Seal Patent Office on the 25th
September 1879.
WILLIAM HENRY NORTHCOTT, late of 8, Union Court, Old Broad Street, London,
E.C., now of Hatcham Ironworks, Pomeroy Street, London, S.E. "IMPROVEMENTS
IN MACHINERY OR APPARATUS FOR COMPRESSING AIR AND OTHER GASES."
My improvements in machines or apparatus for compressing air and other gases
refer mainly to those parts of the machinery directly employed in the compression
and not to the actuating or driving part. The construction of my improved
machinery is illustrated by a series of sectional views, numbered 1 to 6 in the Sheet
of Drawings appended hereto, and will be fully understood by the aid of the
following description :-
The
Figures 1 and 2 are two sectional elevations of one form of my compressor,
wherein a is the main cylinder, into which air or other gas is drawn at the valve b,
a spray of water being at the same time admitted through the channel c.
piston d works within the cylinder a, and draws air into the cylinder by its upward
movement, the apparatus, as shown, being arranged to work vertically. The piston
rods, as in this case there are two, e, e, are attached to the piston d, and proceed
outwards through stuffing boxes f, f, to the crank or steam piston driving the com-
pressor. The air or other gas in the cylinder at the end of the upward stroke of
the piston d is on the down stroke of this piston forced through the valve
into a
smaller cylinder h. This cylinder is formed by a continuation upwards of the main
piston d. The piston i belonging to the cylinder his stationary. When the
piston d is at the bottom of its stroke the air drawn into a has been wholly com-
pressed into the cylinder h, which has a smaller capacity than the first or main
cylinder a. On the next upward stroke of the main piston d the valve g closes, a
fresh supply of air is drawn into the cylinder a, whilst the contents of h are expelled
through the valve k and cooling coil off to a reservoir or other receptacle at m.
These cylinders are so proportioned in size that the same maximum strain comes
upon each piston. Sometimes instead of admitting water at c I admit it by a
smaller valve at n opening into the water chamber. The main cylinder a is pro-
vided with a jacket o, through which a circulation of water is maintained by means
either of a separate pump or other ordinary means, but preferably by the action of
the apparatus itself, as will presently be described. The small valve t on the top
of the cooling coil is an escape or safety valve. The circulating or cooling water
enters the jacket by the valve p, and passes through holes q, q, to the inside of the
cylinder a on the upper side of the piston d, and is expelled through the valve r.
Or the water may be drawn in at r and expelled at p, or otherwise, the object
being to bring a continuous supply of cold water into contact with all the parts
likely to rise in temperature in consequence of the compression. The water circu-
lation is effected without the aid of any separate pump by the motion of the
piston d, which alternately increases and decreases the capacity of the water
chamber after the manner of a pump. The downward motion of the piston d
causes water to flow into the water chamber through the suction valve p, and its
upward motion expels it through the valve r. The actual quantity drawn in is
regulated by a cock on the suction, or other usual means. 8, 8, are pillars, whereby
the air compressing cylinder is attached to the steam cylinder or baseplate.
The compressor, as described, completes its work in two stages, but for very high
pressures the air delivered at m is conveyed into another compressor of similar con-
struction, and there further compressed.
In some cases I introduce a cooling coil between the cylinders a and h. This
coil receives the air from a valve situated similarly to the valve n, and delivers it
to another valve arranged in the same manner, but communicating with the cylin-
der h. Figure 3 shows a compressor in which the compression of the air or other

page_text: gas is effected in four stages. a is the main cylinder; b, its piston, the upward
motion of which causes air to flow in at the valve c. On the downward stroke the.
air is expelled into the chamber d through the valve e. On the next upward stroke
the air is expelled through the valve finto the chamber g, and on the next down-
ward stroke the air in g is expelled through the valve h into the inner chamber i,
thence again on the next upward stroke through the valve k into the cooling coil l,
and off to the reservoir at m. The circulating water is drawn in at n, and expelled
at o by the same means as before.
Figure 4 shows a somewhat different form of my 4 stage compressor. Air drawn
into a is compressed first into b, secondly into c, thirdly into d, and fourthly into
the reservoir. The cooling water is circulated as before.
In Figure 5 the air drawn into a is compressed into b, then into c, and again into
the reservoir through the valve d, this being a three stage compressor.
In Figure 6 the air or other gas with a slight admixture of water is drawn
through the valve a into the cylinder b. It is then compressed into the cylinder
or chamber c, then through the valve d and the cooling coil e into the chamber f,
then again into the reservoir through the cooling coil g, the compression in this case
also being effected in three stages. The cooling water is circulated by means of a
separate pump, or its equivalent.
In witness whereof, I, the said William Henry Northcott, have hereunto set
my hand and seal, this Twenty-fourth day of September, in the year of
our Lord One thousand eight hundred and seventy nine.
BUDU NADTHCOTT