IMPROVEMENTS IN AIR ENGINES
Year: 1875

page_text: LETTERS PATENT to John Garrett Tongue, of the Firm of Tongue
& Birkbeck, of 34, Southampton Buildings, Chancery Lane, in
the County of Middlesex, Patent Agents, for the Invention of
** IMPROVEMENTS IN AIR ENGINES."—A communication from abroad by
Alexander Kirk Rider, of Walden, in the County of Orange, and
State of New York.
Sealed the 10th March 1876, and dated the 30th September 1875.
PROVISIONAL SPECIFICATION left by the said John Garrett Tonguo
at the Office of the Commissioners of Patents, with his Petition,
on the 30th September 1875.
I, JOHN GARRETT TONGUE, of the Firm of Tongue & Birkbeck,
of 34, Southampton Buildings, Chancery Lane, in the County of Mid-
dlesex, Patent Agents, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN AIR ENGINES," a communication to me from
abroad by Alexander Kirk Rider, of Walden, in the County of Orange,
and State of New York, to be as follows :-
This Invention relates to engines which are designed to be operated by

page_text: the successive compression, heating, expansion, and cooling of atmospheric
air or other gaseous fluid or vapor applied, either at its normal density
or at a higher or lower pressure as desired, such air, gascous fluid, or
vapour being used continuously, and merely passing from one portion of
the engine to another part thereof alternately, and requiring no renewal
besides what may be necessary to supply deficiencies consequent on
leakage. The engine comprises a power or working cylinder and a com-
pression or supply cylinder, with their respective pistons, packings,
connections, and main or fly wheel shaft, together with a heater, re-
generator and cooler, and connecting openings or passages, which devices
under different constructions, combinations, and arrangements arc
used in other engines of the description this Invention relates to.
The Invention relates to certain novel constructions and combinations
or arrangements of various parts of the engine, including a disposition of
the compression chamber and its cooler below the air passage connecting
said chamber with the heater of the power cylinder, whereby the
lubricant used is prevented from clogging said passage and parts con-
nected therewith, and is collected in the bottom of the chamber.
Said Invention likewise comprises in combination with the power and
compression cylinders and heater of the engine, a regenerator composed
of plates arranged horizontally in the passage between said cylinders,
and communicating therewith at its ends for the purpose of heating and
cooling the air passing from one cylinder to the other, and traversing
said regenerator.
The Invention also rolates to a novel means of packing the cylinders
or their pistons, whereby numerous specific advantages are obtained,
and an air engine combining increased durability with efficiency is pro-
duced.
The object or objects and nature of the Invention having been thus
explained, it will now be described with reference to the accompanying :
Drawing.
Figure 1 represents an air engine constructed in accordence with the
Invention, and Figure 2 an end view upon a larger scale of the
regenerator.
A is the power cylinder situated directly over the fire-chamber B, and
having attached to its lower flange 6 the heater O which may be of any
suitable construction. Fitted to and inserted in the lower interior

page_text: portion of the power cylinder A. is, a shield or tube D, the use of
which is to deflect and distribute the inflowing air in a thin sheet over
the interior surface of the heater O, and thereby serve to produce a most
efficient heating of the charge of air.
E is the power piston, the advantageous construction of which, as
here shown, is that known as the "trunk," but any other kind may be
used. Said piston is extended downwards into the heater as usual, and
its lower portion is filled with non-conducting material to prevent the
undue heating of the cylinder and packings; it is shown connected
direct to the crank F on the engine shaft S, but may be connected by
beam or lever if preferred; G, G³, are the piston packings, which may
be of leather. These packings are in duplicate for each cylinder; the
lower one of these packings has its lap downwards to resist the escape
of the air below the piston while the upper packing has its lap upwards
to prevent the lubricating material from entering too freely into the
cylinder, and also to prevent the ingress of air when the interior
pressure is less than that on the interior of the piston which will
occur under certain conditions; between these two packings G, G', is
a relief ring H. This ring is of peculiar construction, being much
▸ broader or thicker on its inner surface than its outer one, which latter
unites with the former by easy upper and lower curves which gives to
it a flat outer disc shape and inner upright cylindrical form, and so that
it meets the surface of the piston as a fillet on a flange meets its corre-
sponding cylinder or groove. The inner edges of said ring are made
3 as sharp and thin as practicable; the object and use of this relief ring
is important.
As leather packings are usually made they have a tendency to jam
and produce great friction when the direction of motion under pressure
is such as to condense the lap; the combined action of pressure and
motion forcing the leather into a sharp corner, and against the cylinder
in internal packings or against the piston in trunk pistons where the
packing is external. The relief ring constructed, as described, entirely
obviates this difficulty by allowing the packing to slide on to the curvi-
linear surface and effectually relieves the friction by the insinuation of
the sharp edges of the ring between the piston and packing at the point
of greatest resistance. The packing has thus a vertically changing
motion in the direction of the pistons travel, the acting surface boing
reduced where the piston's motion is towards the packing, and increases

page_text: when the motion is reversed. The relief ring is in this case made double
acting, that is, it has a relieving edge on both sides; it may however
be made single acting when only one packing is used under pressure,
and in that case only one side of the ring will require the relieving
edge. Said relief ring and packings are held in position by the cap
ring I, which is dished out on its upper side to give a convenient
reservoir for the lubricant, and it is secured by bolts passing through the
cap ring and an upper flange on the cylinder.
When such relief ring is used with interior packings as in the ordinary
construction of piston the same arrangement of parts will be made
excepting that the plano-cylindric form will be on the exterior edge of
the relief ring in place of the interior as described. J is the compression
cylinder, having about the same piston development or area as the power
cylinder. It is also fitted with a trunk piston K, and has packings
G, G', and interposed relief ring H, as herein-before described with
reference to the power cylinder A and its piston E. Said cylinder J
rests on and is secured by its lower flange c to the cooler L, and is
connected to the power cylinder by the passage M.
The cooler L is situated immediately under the compression cylinder J,
and on its position and proper construction greatly depends the efficiency
of the engine. It is made double to permit a constant current of cold
water to surround the compression chamber J¹ and keep it cool. The
compression chamber J¹ extends downwards from the lower portion of
the compression cylinder J to the base of the engine, and the piston K
of the compression cylinder is made to fit it loosely and to extend to the
bottom of the compression chamber at the lowest part of the stroke.
This position of the compression chamber J', namely, wholly below the
air passage M, causes the oil used in lubricating to flow downwards, and
collect in the bottom of the compression chamber from whence it can be
readily blown out. This prevents the clogging up of the passage M, or
other parts which would otherwise occur.
The compression piston K nearly fills up the interior of the com-
pression chamber, and thereby causes the air on its return from the
heater to be presented in a very thin sheet to the cold surface of the
compression chamber J', and gives the highest efficiency in cooling the
air previous to its compression. R is the regulator; it is situated in the
passage M, between the power and compression cylinders, and is
traversed each way by the air passage from one cylinder to the other.

page_text: It is constructed of thin plates d, made preferably of cast iron. The
edges e of these plates are thickened so as to give a uniform space
between each plate of about 3 of an inch, more or less. Said plates are
disposed lengthways of the passage, and give an uninterrupted air way
with the least resistance through and between them. The plates are set
on edge to afford the greatest possible facility for their removal through
a bonneted opening in case they require cleaning. F is the crank on
the shaft S to which the compression piston K is attached.
The cranks F, F, are arranged from about 85 to 98 degrees apart,
that is the one in advance of the other. Their exact position is
dependent on the amount of clearance or waste spaces around the
pistons and in the passage ways. The cranks being furthest apart when
the clearance is at a minimum, the direction of revolution is such that
the power crank is in advance of the compression crank.
When the engine is designed for pumping the pump is bolted to the
cooler and discharges into it, and the pump may be worked by an arm
extending from an ear of the compression piston, the cooler forming a
part of the water pipe..
The operation of the engine is briefly as follows:-The compression
piston K first compresses the cold-air in the compression chamber J' into
about one-third its normal volume, more or less, when by the advancing
or upward motion of the power piston E and the completion of the
down stroke of the compression piston K, the air is transferred from
the compression chamber J', through the regenerator R, and into the
heater C, without appreciable change of volume. The result is a great
increase of pressure corresponding to the increase of temperature, and
this impels the power piston E up to the end of its stroke. The pressure
still remaining in the power cylinder and reacting on the compression
piston K, forces the latter upwards till it reaches nearly to the top of
its stroke, when by the cooling of the charge of air the pressure falls to
its minimum, the power piston descends and the compression again
begins. In the mean time the heated air in passing through the
regenerator has left the greater portion of its heat in the regenerator
plates, to be picked up and utilized on the return of the air towards the
heater as in other hot air engines.

page_text: SPECIFICATION in pursuarce of the conditions of the Letters Patent,
filed by the said John Garrett Tongue in the Great Seal Patent
Office on the 29th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoHN
GARRETT TONGUE, of the Firm of Tonguo & Birkbeck, of 34, South-
ampton Buildings, Chancery Lane, in the County of Middlesex, Patent
Agents, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of September, in the
year of our Lord One thousand eight hundred and seventy-five, in
the thirty-ninth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Garrett Tongue,
Her special license that I, the said John Garrett Tongue, my exe-
cutors, administrators, and assigns, or such others as I, the said
John Garrett Tongue, my 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 AIR ENGINES," (a communi-
cation to me from abroad by Alexander Kirk Rider, of Walden, in
the County of Orange, and State of New York,) upon the condition
(amongst others) that I, the said John Garrett Tongue, my executors
or administrators, by an instrument in writing under my, or their,
or one of their hands and scals, 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 immediately
after the date of the said Lotters Patent.
NOW KNOW YE that I, the said John Garrett Tongue, 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 relates to engines which are designed to be operated
by the successive compression, heating, expansion, and cooling of
atmospheric or other gaseous fluid or vapour applied either at its

page_text: normal density or at a higher or lower pressure, as desired, such air,
guscous fluid, or vapour being used coutinuously and merely passing
from one portion of the engine to another part thereof alternately, and
requiring no renewal besides what may be necessary to supply dificiences.
consequent on leakage. The engine comprises a power or working
cylinder and a compression or supply cylinder with their respective
pistons, packings, connections, and main or fly wheel shaft, together
with a heater, regenerator, and cooler, and connecting openings or
passages, which devices under different constructions, combinations, and
arrangements are used in other engines of the description this Invention
relates to.
The Invention relates to certain novel constructions and combinations
or arrangements of various parts of the engine, including a disposition of
the compression chamber and its cooler below the air passage connecting.
said chamber with the heater of the power cylinder, whereby the
lubricant used is prevented from clogging said passage and parts_con-
nected therewith, and is collected in the bottom of the chamber.
Said Invention likewise comprises in combination with the power and
compression cylinders and heater of the engine, a regenerator composed
of plates arranged horizontally in the passage between said cylinders,
and communicating therewith at its ends for the purpose of heating and
cooling the air passing from one cylinder to the other and traversing said
regenerator.
The Invention also relates to a novel means of packing the cylinders.
or their pistons, whereby numerous specific advantages are obtained,-
and an air engine combining increased durability with efficiency is
produced.
The object or objects and nature of the Invention having thus
explained, it will now be described with reference to the accompanying.
Drawing.
Figure 1 represents an air engine constructed in accordance with
the Invention, and Figure 2, an end view upon a larger scale of the
regenerator.
A is the power cylinder situated directly over the fire-chamber B, and
having attached to its lower flange b the heated O which may be of any
suitable construction. Fitted to and inserted in the lower interior

page_text: portion of the power cylinder A is a shield or tube D, the use of which
is to deflect and distribute the inflowing air in a thin sheet over the
interior surface of the heater C, and thereby serve to produce a most
efficient heating of the charge of air.
E is the power piston, the advantageous construction of which as
here shown is that known as the " trunk," but any other kind may bo
used. Said piston is extended downwards into the heater as usual and
its lower portion is filled with non-conducting material to prevent the
undue heating of the cylinder and packings. It is shown connected
direct to the crank F on the engine shaft S, but may be connected by
beam or lever if preferred; G, G', are the piston packings which may be
of leather; these packings are in duplicate for cach cylinder. The
lower one of these packings has its lap downwards to resist the escape of
the air below the piston, while the upper packing has its lap upwards to
prevent the lubricating material from entering too freely into the
cylinder, and also to prevent the ingress of air when the interior pressure
is less than that on the exterior of the piston, which will occur
under certain conditions. Between these two packings G, G³, is a relief
ring H; this ring is of peculiar construction, being much broader or
thicker on its inner surface than its outer one, which latter unites with
the former by easy upper and lower curves, which gives to it a flat outer
disc shape and inner upright cylindrical form, and so that it meets the
surface of the piston as a fillet on a flange meets its corresponding
cylinder or groove. The inner edges of said rings are made as sharp
and thin as practicable. The object and use of this relief ring is
important.
As leather are usually made, they have a tendency to jam and
produce great friction when the direction of motion is such as to
condense the lap; the combined action of pressure and motion forcing
the leather into a sharp corner and against the cylinder in internal
packings, or against the piston in trunk pistons where the packing
is external. The relief ring constructed as described entirely obviates
this difficulty by allowing the packing to slide on to the curvil-
linear surface, and effectually relieves the friction by the insinua-
tion of the sharp edges of the ring between the piston and packing at
the point of greatest resistance. Tho packing has thus a vertically
changing motion in the direction of the piston's travel, the acting
surface being reduced where the piston's motion is towards the packing

page_text: and increases when the motion is reversed. The relief ring is in this
case made double acting, that is, it has a relieving edge on both sides, it
may however be made single acting when only one packing is used
under pressure, and in that case only one side of the ring will requiro
the relieving edge. Said relief ring and packings are held in position
by the cap ring I, which is dished out on its upper side to give
a convenient reservoir for the lubricant, and it is secured by bolts
passing through it, through the cap ring, and an upper flange on the
cylinder.
When such relief ring is used with interior packings as in the
ordinary construction of piston, the same arrangement of parts will be
made, excepting that the plain cylindric form will be on the exterior
edge of the relief ring in place of the interior as described. J is the
compression cylinder having about the same piston developement or
area as the power cylinder; it is also fitted with a trunk piston K and
has packings G, G', and interposed relief ring H, has herein-before
described with reference to the power cylinder A and its piston E.
Said cylinder J rests on and is secured by its lower flange c to the
cooler L, and is connected to the power cylinder by the passage M.
The cooler L is situated immediately under the compression cylinder J,
and on its position and proper construction greatly depends the
efficiency of the engine; it is made double to permit a constant current
of cold water to surround the compression chamber J' and keep it cool.
The compression chamber J extends downwards from the lower portion
of the compression cylinder J to the base of the engine, and the
piston K of the compression cylinder is made to fit it loosely and to
extend to the bottom of the compression chamber at the lowest part of
the stroke. This position of the compression chamber J, namely,
wholly below the air passage M, causes the oil used in lubricating to
flow downwards and collect in the bottom of the compression chamber,
from whence it can be readily blown out; this prevents the clogging up
of the passage M or other parts which would otherwise occur.
The compression piston K. nearly fills up the interior of the com-
pression chamber, and thereby causes the air on its return from the
heater to bo presented in a very thin sheet to the cold surface of the
compression chamber J¹, and give the highest efficiency in cooling tho
air previous to its compression. R is the regulator; it is situated in tho
passage M between the power and compression cylinders, and is traversed

page_text: each way by the air passage, from one cylinder to the other. It is
constructed of thin plates d made preferably of cast iron; the edges e
of these plates are thickened so as to give a uniform space between each
plate of about of an inch, more or less. Said plates are disposed
lengthways of the passage and give an uninterrupted air way with the
least resistance through and between them. The plates are set on edge
to afford the greatest possible facility for their removal through a
bonnetted opening in case they require cleaning. F is the crank on the
shaft S, to which the compression piston K is attached.
The cranks F, F', are arranged from about 85 to 98 degrees apart,
that is, the one in advance of the other. Their exact position is
dependent on the amount of clearance or waste spaces around the
pistons and in the passage ways. The cranks being farthest apart when
the clearance is at a minimum, the direction of revolution is such that
the power crank is in advance of the compression crank.
When the engine is designed for pumping the pump is bolted to the
cooler and discharges into it, and the pump may be worked by an arm
extending from an ear of the compression piston, the cooler forming a
part of the water pipe.
The operation of the engine is briefly as follows:-The compression
piston K first compresses the cold air in the compression chamber J'
into about one-third its normal volume more or less, when by the
advancing or upward motion of the power piston E and the completion
of the down stroke of the compression piston K the air is transferred
from the compression chamber J¹ through the regenerator R and into
the heater C without appreciable change of volume; the result is a
great increase of pressure corresponding to the increase of temperature,
and this impels the power piston E up to the end of its stroke. The
pressure still remaining in the power cylinder and reacting on the
compression piston K forces the latter upwards till it reaches nearly to
the top of its stroke, when by the cooling of the charge of air the
pressure falls to its minimum, the power piston descends, and the com-
pression again begins begins. In the meantime the heated air in passing
through the regenerator has left the greater portion of its heat in the
regenerator plates to be picked up and utilized on the return of the air
towards the heater as in other hot-air engines.
Having thus described the nature of this Invention and the manner
of performing or carrying the same into practice, what I claim is.—

page_text: First. The compression chamber J' with its cooler Larranged below
the air passage M which connects said chamber with the heater O of the
engine, whereby the lubricating material is restrained from clogging the
passage M and other parts connected therewith, and is collected in the
bottom of said chamber substantially as herein-before specified and
shown in the Drawings annexed.
Secondly. I claim in combination with the power and compression
cylinders A and J and heater C the regenerator R composed of plates &
arranged horizontally in the passage M between said cylinders, and
communicating therewith at its ends, substantially as herein-beforo
described and represented in the Drawings annexed, whereby the air
passing from one cylinder to the other traverses said regenerator and
the air is heated and cooled, as and for the purpose described.
Thirdly. I claim the relief rings H having their inner and outer
surfaces of different breadths united by one or more curves, and leaving
a sharp edge at their junction with the piston or wearing surface in
combination with the packings G, G, substantially as herein-before
specified and represented in the Drawings annexed.
Fourthly. I claim the combination of the power cylinder A, the
piston E, the shield or tube D, the heater O, the passage M and re-
generator R, the compression chamber J' and its cooler L, and the
compression cylinder J and its piston K, the whole being arranged to
act substantially in the manner and for the purposes as herein set forth
and represented in the Drawings annexed.
Lastly. I claim the improved arrangement and combination of
mechanical parts in the construction of air engines arranged to act
substantially in the manner and for the purposes herein-before described
and represented in the Drawings annexed.
In witness whereof, I, the said John Garrett Tongue, have here-
unto set my hand and seal, this Twenty-seventh day of March, in
the year of our Lord One thousand eight hundred and seventy-
six.