IMPROVEMENTS FOR DIRIFISHING THE CONSUMPTION OF FUEL, AND IN PARTICULAR AN ENGINE CAPABLE OF BEING AFFLIED TO THE MOVING MACHINERY OF A PRINCIPLE ENTIRELY HAW
Year: 1816

page_text: LETTERS PATENT to Robert Stirling, of Edinburgh, Clerk, for his
invented "IMPROVEMENTS FOR DIRIFISHING THE CONSUMPTION OF FUEL, AND IN
PARTICULAR AN ENGINE CAPABLE OF BEING AFFLIED TO THE MOVING MACHINERY OF A
PRINCIPLE ENTIRELY HAW."
6 months.
Dated 16th November 1816.

page_text: LETTERS PATENT to Robert Stirling, of Edinburgh, Clerk, for his
invented "IMPROVEMENTS FOR DINIFISHING THE CONSUMPTION OF FUEL, AND IN
PARTICULAR AN ENGINE CAPABLE OF AKING APPLIED TO THE MOVING MACHINERY ON A
PRINCIPLE ENTIRELY NEW."
6 months.
Dated 16th November 1816.

page_text: LETTERS PATENT to Robert Stirling, of Edinburgh, Clerk, for his
invented "IMPROVEMENTS FOR DIMINISHING THE CONSUMPTION OF FUEL, AND IN
PARTICULAR AN ENGINE CAPABLE OF BEING APPLIED TO THE MOVING MACHINERY ON A
PRINCIPLE ENTIRELY NEW."
6 months.
Dated 16th November 1816.

page_text: THE CENTENARY OF THE HEAT REGENERA-
TOR AND THE STIRLING AIR ENGINE.
THE library of the Patont Office luis rocontly boon
the recipient of the original specification in the hand-
writing of the inventor, the Rev. Robert Stirling,
D.D., of the Hent "Regenerator," and the Stirling
Air Engine (Letters Patent No. 4081 of 1816). For
Home reason, not definitely ascortained, this specifica-
tion, though duly signed, attested and stamped, was
not enrolled. Hence, it does not appear in tho
Official Blue-book serios, and has always boon
treated as a lapsed application. It is now pub.
lished in extenso for the first time, although it is
known that copius of the Scotch specification were
produced in evidence in the nolebrated trials of the
Neilson Hot-blast patent. It is, we believe, ostab-
lished lunt the first appliention of the rogonorative
principlo to iron smelting by James Baird in 1825
was due to the suggestion of Robert Stirling, who,
it is stated, lind included iron smelting furnace" in
the original draft of his specification, but had
struck out the words, and gave only one examplo,
selecting a glass furnace for the purposO.
omission probably savod Neilson's patent, while
it accounts for the fact that Stirling was not called
to give ovidonee at the Edinburgh trial in spite of
ho prossure put upon him by tho dofondants. It
should be observed that the term "rogenerativo
furnace was not coined by Stirling, who olowhoro
stated that he preforryd to doscribe his invention as
an "Economisor," but the term coined by Ericsson
was so firmly rooted in the langungo in Siemons' timo
that the latter accepted it under protest (Proo. Inst.
C.E., vol. xii., 1852-3). Further, it is worthy of note
that nearly all the applications of the regonorativo
principle in heating and cooling wore forosoon by
Stirling, and indicated by him in his specification.
Thin
The principle of the Stirling Air Engine differs from
that of Sir George Cayloy (1807), in which tho nir
in forced through the furnace and exhausted, whoroas
in Stirling's ongine the air works in a closed circuit.
It was to it thint the invontor devoted most of his
attention. A two horso-power engine, built in 1818,
for pumping water at an Ayrshire quarry, continuod
to work for some time, until a carelous attendant
allowed tho hontor to become overheated. This
experiment proved to the inventor that, owing to tho
low working pressure obtainable, the ongine could
only be adapted to small powers for which there was
at that time no domand. His youngor brother,
James Stirling, O.E., suggested, in 1824, using com-
pressed air, and in 1843 built an engine of 45 brake
horso-powor, which successfully drove tho machinery
at the Dundee Foundry for Hovoral yours, thus domon-
strating the adaptability of the principle to higher
powers.
It may be of interest to noto horo that Robert
Stirling was born at Clong. Methvin. Porthshire, in
1790, and entered the Church. At tho dato of his
invention, 1816, he was twenty-six years of age, and
had just been ordained to his first parish.
He
was greatly esteemed as a minister, and was
a noted classical scholar, as well as a sciontist, and
before he died, in 1878, was the Fathor of tho Olurch
of Scotland. His grandfather, Michael Stirling.
of Glassingal, Dunblane, invented thin first rotary
thrashing machino in 1766 (vide Encyclopedia Brit-
tanica, third edition-Thrashing). His brother
James was a celebrated Civil Engineer in Edinburgh,
and four of his sons wero ongineers, who all made
their mark in tho engineering world. Two of them,
Patrick and James, are well known in this country
to locomotive engineers of the present generation.
SPECIFICATION OF STIRLING'S PATENT No. 4081 of 1816.
All my Improvements for diminishing the consumption of fuol
connint. of the different forms or modifications of a Now Mothod,
Contrivance, or Mechanical arrangement for henting and cooling
Liquids, Airs or Gases, and other Bodion by the time of which
Contrivance Hent is abstracted from one portion of such liquids,
airs, and other bodios and communicated to another portion with
very little loss: so that in all cases where a constant accession
of heated liquids or other bodies is required, the quantity of fuol
necessary to minintain or supply it is by this contrivanco groitly
diminished. The First Modification of said Contrivaner or
arrangement is described as follows:-A 1 fig. 1st in n pipe,
channel, or mange, formed of Metal, Stone, Bricks or other
Materials according to circumstaners i.. according to the Cho-
mical agencies of the bodies to be heated or cooled and the degree
of heat in said bolins.-The Hot liquid, gas, or body to be cooled
in by any means made to onter the passage nt A and to pass
along to its other extremity H-In its progress it gives out its
heat to the sides of the passinge or to any bodies contained in it
and issues at Bat nearly the original temperature of the passago.
In this manner the extremity at A and a considerable portion
of the passage is heated to nearly the temperature of the Hot
liquid while the extremity B still retains its original tompern-
Lure nearly. When the temperature of the paaange at B has been
raised a few degrees the motion of the fluid from A to B is stopped
And a portion of fluid which is required to be Hentod and which
is supposed to be a few degrees colder than the extremity of the
passage at B is made to traverse the same passage in a contrary
Direction i.. from B to A; by which means it receives heat from
the sirles of the passage or other bodies contained in it and issues
at A at nearly the same temperaturo with the fluid to be cooled.
When the temperature of the passage at A has thus been lowered
n few degrees, the process is again stopped and a portion of the
fluid to bo cooled is made to pass from A to B and so on 'alter-
nately-
Tho Second Modification of my maid Contrivance or arrange-
ment consists in interposing a thin plate of Metal or other
materials, according to circumstances, between two currents of
liquid gas or vapour which are made to run in opposite directions.
AB fig. 2nd represents such a plato and c, d, two passages
between which it is interposed. The fluid to be cooled is made to
trave the piange d from A to R and the fluid to be heated is
made to travers the passage d from B to A.-The extremity of
the plate at A is kept Hot hy the current in d and the extremity
Bis kept cald hy the current in The plate A, Babstracts the
hont from the fluid in the passage d and communicates it to that
in with very little lons.The waste or esente of heat from the
panges in prevented by their being surrounded with Charcoal
powder, wood, bricks or any aubatanen that does not easily
permit hoal to pass through it, as is represented at c. d. c. f.
fig. 1st and 2nd-In the construction of the passages in both
Modifications of my contrivance for heating and cooling liquids
and other holies I absorve the following rulon:-
1. When the passages are made of metal or any other substance
that conducte or transmits heat easily I make the metal or other
substance as thin as possible to prevent the heat from being
transmitted in this manner from the hot to the cold extremity of
the passages.-2. Liquids and airs being very imperfect con.
ductors of hont I make the passages very narrow (at least in one
direction) in proportion to their length, for the purpose of heating
and cooling more completely the liquids or airs that pass through
them. A transverse section of the passages is given at A and B
C fig. 3rd.-3. When tho passages cannot be made sufficiently
narrow I make their sides jagged or rough hy hodien projecting
from them as represented at fig. 4 or I adopt any similar method
for promoting the internal motions of the fluids and the randy
cominunication of heat to them or to the passage.-4. When
the width of the passage cannot be sufficiently diminished 1
encrease its longth in order to attain the same end.-The form
and construction of the tubes, passages and plates in both the
inorifications of my general Contrivance or Arrangement may he
varied according to circumstances; but the benefit to be derived
from this contrivance arises from the fluids and other bodies to
he heated and those to be cooled being made to move in opposite
directions and it is for the invention or improvement of this
Arrangement that I have applied for and obtained His Majesty's
Letters l'atent.
Having thus described and ascertained the nature of my Inven
tion I shall now describan sovoral of its numerous and useful
applications. The First form or Modification of my general
contrivance or arrangement may bo applied to diminishing the
consumption of fuel in Glass house and other furnaces wherever
a high degree of heat is required, and the nature of the processes
carried on in these furnaces admite of their being accurately
closed, and this application is also capable of producing a much
more intenso heat than can be raised by the ordinary methods.
A fig. 5 is a furnnon Allod with fuel A. EG and ADE (ric.) are
two flues or passages (a transverse section of which is repre
montod at A fig. 6). Bin a passage for introducing the fuel
nccurately clowed at C.-All other parts are likewise closed so that
no air can man through or have access to the fire but through said
flues. The air which supports the combustion is alternately
introduced at F and U by blowing engines, bellows or any other
moans and the gases and vapours which arise from the fire pass off
in an opposite direction leaving the greater part of their heat in

page_text: the flues in the manner above described.-This heat is taken up
by the air which supports the fire and in again left in the opposite
fluo along with the additional quantity produced by combustion.
In this manner the hoat is nccumulated in the furance and the
parts of the fluns adjacont to it. The bodios to be heated are
placod at 1) and E and the openings by which they are intru-
duond are accurately closed. The furnace and flues are con-
structed of the host firebricks or any matorial that may better
resist the intonso heat, and the Manon work, as in other furnnor,
is made sufliciontly thick to provent the waste of heat.-The
form and managemont of the furnace and flues may be varied
according to circumstances; but it must be remembered that the
narrower and longer the fluos are and the more frequently the
direction of the air is changed the greater is tho saving of fuel
and the intensity of the heat produced.
The Second form or modification of my invention may be
applied to the saving of fuol in Brewories, Distilleries, Dye Works
and other Manufacturus, by transferring heat from one portion
of liquid, air, or vapour to another.-No further directions seem to
be necessary for thono applications but this that the quantity of
fluids which is allowed to run through the respective paragon
must be inversely proportional to the specific heat of the respec.
tivo fluids which may ho learned from books or from observing
the degree to which they are respectively hented or cooled in
thoir paяange-Ity aither of the above described Modifications
of iny ni Arrangement 1 construct my Engine, for moving
Machinery and the following is a general description of the
manner in which this is perforined.-1 employ the Expansion and
Contraction (or rithor) of atmospheric air or any of the permanent.
gases by heat and cold to communicate notion to a piston or
other similar contrivance-In order to produce this expansion
and contraction 1 case tu air to pass from a coll to a hint part
of the engine and the contrary alternately either in the saTE
pange in the manner descrill at the explanation of fig. lnt, or
in different anges as described at fig. 2nd-I apply fire to the
warmest part of the engine, in order to supply the waste of heat
occasioned by its transmission from the hot to the cold parts by
the radiating and conducting power of the materials of which
they are formed, by the change of capacity for hent which
tho air suffers from oondonsntion and rarefaction, and by the im-
possibility of transforring to whole of the heat from the air to the
pasanges and the contrary and I apply a stream of cold air or water
to the collent part of the ongine to carry off anid waste hent.-
The passages are of course llot at the one extremity and Cold at
the other, and in passing through them the air in alternately
hontod and cooled or oxpanded and contracted.-The following
is a particular description of that form of my engine which Y
consider as tho bost.-A A D 1) fig. 7 in a cylinder composed of
three parts accurately joined together by rivats or serows and
rendored nirtight by hammering or soldering the joinings.-The
part A 15 is formed of cast iron and accurately bored, the part
BG is made of shoot or cast iron as thin as possible (as one tenth
of an inch), and tho part C D in of Sheet or Cast iron.-To thin
cylinder is fittod a piston E E which is made airtight in tho usual
way, and provided with rods 11 for communicnting its motion.―
FFGG is a hollow cylinder alan na thin as possible made of sheet
iron covered with thin plates of polished brass or silver to prevent
the waste from radiation and divided into compartments by
plates b. b. for tho samo purpose-It is shut on all sides and air-
iight, kept at a small distanco from the outer cylinder by wheels
a, a, or Buy similar contrivance and furnished with a rori II
working through a stulling in the centre of the pinton, by means of
which it is moved up and down.-This inner cylinder 1 call the
Plunger. The part B D of the outer cylinder is kept hot hy the
flame or heated airs of a firo Capplied at D D madlo to descend
on all sides of the cylinder to C and allowed to escape at e.-The
part A B is kept cool by a stream of air or of water directed upon
it, and the part R Concreases in temperature from 1 to C.-The
temperature of the plunger onereases from F to Gand tho interval
between the cylinder and plunger is partially filled with wires
The Operation of the engine is explained as follows.-The
part of the cylinder surrounded by the flues is heated to a tem-
perature of 480 higher than the part A B-In the position
represented at fig, & the plunger is in contact with the piston, by
which means the included air is brought to the warm part of the
cylinder has its elasticity cucreased and presses upon the piston
with a force greater than that of the atmosphere.The piston is
thus forced downwards and the rod ff and crank g upwards till
the pressure if the included air and that of the atmosphere
become equal. The impulse communicated to the fly carries the
end of the crank towaris q, and the arm // and bent lever i fare
brought to such a position as to depress the rod and thus to
raise the plunger from the piston.-The included air is thus made
to descend between the plunger and cylinder and brought to the
cold part; it is cooled in its descent. has its elasticity
diminished, and its pressure becomes less than that of the atmo-
sphere, the piston is forced upwards, and the crank downwards.-
The revolution of the fly and crank again bring the plunger
towards the piston, the air ascends through the same passage by
which it descended, is heated in its ascent and forces the piston
downwards and the crank upwards, and so on alternately.-In
this manner a rotatory inotion is produced which may be applied
to the moving of machinery.-The forer of the engine is regulated
by allowing a portion of air to escape outwards and inwards by a
small cock which is opened and shut by a governor as in Steam
gines, and placed in the cold part of the cylinder immediately
above the highest ascent of the piston.-The listance which the
rod of the plunger H fig. 7 moves through the piston I call the
Stroke of the plunger and I make it equal to that of the piston
when the difference of temperature in the hot and cold parts of
the cylinder is 480°-When the difference is less than 480* I
make the stroke of the plunger proportionally greater than that
of the piston, and the contrary when the difference is greater.-
The length of the arms of the bent lever in i and of the rod k
which is necessary to make the plunger just touch the piston on
the one hand and the upper end of the cylinder on the other I
determine hy experiment as being the most convenient method
known to me.-i do not answer for the absolute correctness of
those in the plan.The cylinder is inverted to prevent the nil
used to make the piston airtight from getting to the hot part and
wasting the heat. In the foregoing description, wherever I have
specified more than one Material or more than one Method of
performing the same thing. I have placed that first to which I
give the preference; But I reserve to myself the power of using
any materials and applying my new contrivance for heating and
enoling bodies, to the purposes to which it is applicable in any
form or n.anner which further experience may prove to be
advantageous and which is not inconsistent with the terins of his
Majesty's Letters l'atent.
In witness whereof I the said Robert Stirling have hereunto
set my hand and seal this Twentieth day of January in the year
of our Lord one thousand eight hundred and seventeen.
Signed sealed and delivered
in presence of
[Seal of
R.S.
Robt. Stirling
(Rob. Cameron) Accountant in Edinburgh,
(Francis F. Cameron) Preacher of the Gospel in Edinburgh.