IMPROVEMENTS IN THE CONSTRUCTION OF HOT AIR ENGINES
Year: 1854

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical Draughts-
man, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF HOT
AIR ENGINES." -A communication.
Sealed the 30th June 1854, and dated the 6th April 1854.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton
at the Office of the Commissioners of Patents, with his Petition, on the
6th April 1854.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Mechanical Draughtsman, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF HOT
AIR ENGINES" to be as follows:-
This Invention relates, firstly, to the employment of auxiliary heaters for
raising the temperature of the air to be supplied to the engine preparatory to
its entering the main heater. The auxiliary heaters are so connected together
and with each other by means of valves, that the air for the supply of the
engine shall be pumped in against the minimum pressure within the main
heater while it is worked off at the maximum pressure.
The Invention also relates to the passing of the exhaust air from the working
cylinder, together with the smoke and heated gases from the furnace, through
the auxiliary heaters in one direction, while the air for the supply of the engine
is caused to pass in the contrary direction through tubes within these auxiliary

page_text: heaters, by which means the heat is extracted from the exhaust air and smoke,
and transferred to the air on its way from the air pump to the heater.
Great inconvenience has heretofore been experienced in the working of hot
air engines, from the difficulty of obtaining a packing that will resist the great
temperature to which the piston is liable to be raised. To remedy this
inconvenience, it is proposed to refrigerate the piston by means of a constant
stream of cold water, which is injected into the piston through a hollow piston
rod, and made to circulate through its interior. By this means a temperature
not exceeding that of boiling water is preserved.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alfred Vincent Newton in the Great Seal Patent Office
on the 6th October 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, J, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of April, in the year of our Lord
One thousand eight hundred and fifty-four, in the seventeenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Alfred Vincent Newton, Her special license that I, the said
Alfred Vincent Newton, my executors, administrators, and assigns, or
such others as I, the said Alfred Vincent Newton, my executors, admi-
nistrators, 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 THE CONSTRUCTION OF HOT AIR ENGINES,"
being a communication from abroad, upon the condition (amongst others) that
I, the said Alfred Vincent Newton, by an instrument in writing under my
hand and seal, 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 Letters Patent.
NOW KNOW YE, that I, the said Alfred Vincent Newton, 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

page_text: following statement, reference being had to the Drawing hereunto annexed
and to the letters and figures marked thereon (that is to say):-
This Invention, as communicated to me by my foreign correspondent, consists,
firstly, in the employment of auxiliary heaters, which are so connected together
and with each other by means of valves, that the air for the supply of the
engine shall be pumped in against the minimum pressure within the main
heater while it is worked off at the maximum pressure.
The Invention also consists in passing the exhaust air from the cylinder,
together with the smoke and heated gases from the furnace, through the auxiliary
heaters in one direction, while the air for the supply of the engine is caused to
pass in the contrary direction through tubes within these auxiliary heaters, by
which means the heat is extracted from the exhaust air and smoke, and trans-
ferred to the air on its way from the air pump to the heater.
Great inconvenience has heretofore been experienced in the working of hot
air engines, from the difficulty of obtaining a packing that will resist the great
temperature to which the piston is liable to be raised. To remedy this incon-
venience, the Inventor has adopted the plan of refrigerating the piston by
means of a constant stream of cold water, which is made to circulate through
its interior, and thus preserve it at a temperature not exceeding that of boiling
water.
In the accompanying Drawing, Fig. 1 is a plan of the engine; Fig. 2, a
section on the line W, W, of Figures 3 and 4, the shell of the auxiliary heater
being removed to shew the parts within; Fig. 3 is a section on the line Y, Y, of
Fig. 1; Fig. 4, a section on X, X, of Fig. 1; and Fig. 5, an enlarged section
of the main heater on Z, Z, of Fig. 2.
A is the main heater, into which the air is received from the auxiliary heaters,
and in which it receives a final heating preparatory to being admitted to the
working cylinder. B is the fire box; and C, the ash pit of the furnace beneath
the heater. A, a, are vertical tubes which pass entirely through the heater,
and through which the smoke and burning gases from the furnace pass. D is
a chamber, which entirely surrounds the heater and fire box, and which opens
at the top into the chimuey or smoke box E, and communicates with the
chamber beneath the furnace through the openings d in its bottom plate, the
object of which will be explained hereafter. F is an air pipe of communication
between the auxiliary and the main heaters, which is entirely surrounded by
the smoke flue G, and is furnished with a valve b opening downwards at its
lower extremity. H is the auxiliary heater, which is divided into three sec-
tions or minor heaters H1, H2, H3; these sections are separated from each
other and from the ends of the heater by chambers I, I, I, I, formed by close

page_text: fitting partitions ffffff, the chambers I, I, I, I³, communicating
with each other through the tubes C, C, C, K, K³, K. The smoke from the
furnace enters through the pipe G into the chamber 13, thence it passes
through the tubes c, K, into the chamber I, thence through the tubes K', c',
into the chamber I', thence through the tubes K, c, into the chamber I, whence
it passes off by the chimney M.
They, however,
These tubes are
By the arrangement above explained, it will be perceived that the compart-
ments H1, H2, H3, are entirely shut off from the chambers I, I, I, I³, and
from the smoke flues c and K, which pass through them.
communicate with each other through the short tubes L, L.
fitted at their forward ends with valves e, e. The air from the force pump is
admitted into these compartments in succession, passing through the tubes L
and L and the valves e, e¹, in a manner which will be hereafter more fully
described. N is the working cylinder; O, the hot air box which com-
municates with the heater A through the pipe P; Q is the hollow piston,
the piston rod of which is also hollow, as shewn at Fig. 2; g is a tube
enclosed within the hollow piston rod, and penetrating it at about the point h.
R is a receptacle for water; S, S¹, are india-rubber tubes from the top and
bottom of this receptacle, which communicate one with the interior of the
hollow piston, and the other with the small tube enclosed therein. By this
means the water from the receptacle R is caused to circulate continually
through the hollow piston, which is thus prevented from becoming injuriously
heated, as before mentioned. T' is the discharge pipe from the working cylinder,
which is made to enter the ash pit C, immediately beneath the grate bars.
All the advantages resulting from urging the fire with heated air are thus
obtained. The excess of the exhaust air not required by the fire passes through
the openings & into the chamber D which encases the furnace, and escapes
with the heated gases and the products of combustion through the flue G into
the chamber I³, whence the mingled air and gases pass out-in the manner already
described. The object of thus exhausting the hot air from the cylinder into
the ash pit beneath the furnace is two-fold; firstly, the fire is urged with
heated air; secondly, such portion of the exhaust air as is not thus consumed
passes with the products of the furnace into the auxiliary heaters, where it is
refrigerated by the fresh air entering from the force pump, in a manner that will
be presently explained. V is the force pump for supplying the heater with air,
the area of its piston being about one-half that of the working piston. The air
admitted to this pump enters at the valves g', and escapes at valves in the top
of the cylinder into the chamber h', whence it passes by the pipe A' into the
compartment H¹ of the auxiliary heater. It then circulates round the outside

page_text: the pipe
and valve 6 into the heater A.
It is evident that the auxiliary heater may consist of one or more compart-
ments, there being always a valve communication between the last of such
compartments and the main heater.
OPERATION.
The air within the main heater A, as it expands, closes the valve b, which
thus prevents it from returning through the pipe F into the auxiliary heater H;
a charge is then admitted to the working cylinder, the capacity of the heater A.
being such, with relation to the working cylinder, that when cut off at three
quarters stroke, or thereabouts, the pressure within the heater A shall be very
much reduced; the valves b, e', e, then open, or as soon as the pressure in the
compartment is reduced below what it is in the one behind it, and the pressure
for an instant is the same in all the compartments. The expansion caused by
the extreme heat within the heater A soon closes the valve b, the valves e', e,
being in like manner closed, as the heat within the compartment H³ is greater
than that within H, and so on, it being nearer to the furnace.
The pressure within H thus always remains at very near the minimum,
and as the air is pumped into this compartment, it is evident that it is only
resisted by this minimum pressure, while it is worked off from the main heater
A at its maximum pressure. The exhaust air from the cylinder, as before
stated, enters the close ash pit C, and the fire is thus urged by a hot blast.
That portion of the exhaust air not required by the fire passes off with the
products of combustion, and is refrigerated in the auxiliary heater H by the
entering air. The exhaust air may be made to enter the auxiliary heater with
the smoke from the furnace, and thus a portion of the advantages above
described will be secured, but the exhaust beneath the fire is preferable for the
reasons already set forth. Several heaters and auxiliary heaters may be adapted
to a single engine, a charge of air being taken from each in succession.
Having now set forth the nature of the Invention of "Improvements in the
Construction of Hot Air Engines," as communicated to me from abroad, and
explained the manner of carrying the same into effect, I wish it to be under-
stood, that under the above in part recited Letters Patent I claim the above-
described auxiliary heater of one or more compartments in combination with

page_text: the main heater, the two being connected by pipes and valves in the manner
set forth; the products of combustion passing through the said auxiliary heater
in one direction, while the air from the force pump passes in the opposite
direction, by which means the exhaust air and the products of combustion are
refrigerated, and the air from the force pump enters against a pressure much
less than that which exists in the main heater at its maximum.
Second, the method within described of refrigerating the piston by the use
of a current of water in the manner set forth.
Third, I claim throwing the exhaust air from the working cylinder into the
ash pit in the manner described, and passing it off to be refrigerated with the
products of combustion, as set forth.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto
set my hand and seal, the Sixth day of October, in the year of our Lord
One thousand eight hundred and fifty-four.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
A. V. NEWTUN. (L.S.)