IMPROVEMENTS IN THE CONSTRUCTION OF PORTABLE STEAM ENGINES
Year: 1866

page_text: LETTERS PATENT to George Davies, of No. 1, Serle Street, Lincoln's
Inn, in the County of Middlesex, and No. 87, St. Vincent Street,
in the City of. Glasgow, Civil Engineer and Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN THE CONSTRUCTION OF PORTABLE STEAM
ENGINES. A communication from abroad by Isidore Nillus, the younger,
of Paris. Machine Maker.
Sealed the 27th July 1866, and dated the 5th March 1866.
PROVISIONAL SPECIFICATION left by the said George Davies. at the
Office of the Commissioners of Patents, with his Petition, on the 5th
March 1866.
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the
County of Middlesex, and No. 87, St. Vincent Street, in the City of Glasgow,
Civil Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF PORTABLE STEAM ENGINES,"
(a communication to me from abroad by Isidore Nillus, the younger, of Paris,
Machine Maker,) to be as follows:-
The Invention which forms the object of the present application is
characterized by the construction of a system of portable steam engine, which
offers the same economical advantages and ease of working as the best fixed
engines. The relatively small dimensions of portable engines render very
difficult the construction of a good boiler, having a furnace large enough, and

page_text: a sufficiently extended heating surface without being obliged to increase the
intensity of the fire under conditions very prejudicial to the economy of the
combustible and to the preservation of the boiler itself. Besides, by the
superposition of the working parts of the engine and the boiler, serious
difficulties are experienced in conveniently isolating the working parts, and
protecting them from the effects of too great a heat, and at the same time
giving them the necessary connection and solidity. It is to solve these
principal difficulties, as well as various others hereafter alluded to, that the
following combination and arrangement have been designed. The boiler is
composed principally of a horizontal cylindrical body and a vertical body, the
lower part of which contains the furnace, and which rising considerably forms
a vast steam chest. The interior of the outer casing contains the furnace, a
water space with fire tubes, and a smoke box, to which the chimney is con-
nected externally. This arrangement allows a greater traverse to the products
of combustion than those ordinarily employed. The heated gases and flames
(which are not so liable to be extinguished as when they enter tubes of small
diameter) circulate through the boiler tube, the heating surface of which is
considerable. At its extremity these gases rise, and pass through tubes which
conduct them towards the front of the engine into the smoke box, which is
connected to the chimney by a conduit which passes through the steam chest.
Thus the utilization of the heat of the products of combustion is as complete
as possible; and, moreover, the latter part of their passage is utilized for
drying the steam contained in the reservoir or steam chest, whence it is taken
away directly to supply the cylinder. Numerous experiments have shown
that the hourly consumption of fuel per horse-power was less and the weight
of water vaporized by a given amount of fuel was more than is usually
attained by portable engine boilers. As for the working parts which compose
the engine they present all the peculiarities by which the most complete and
improved engines are distinguished; only the framing by which the whole of
the other parts are exclusively supported is of a structure specially appropriate
to this kind of engine, the driving shaft of which (as is well known) cannot
bave any external support. The plate which serves as a base for all the
engine is mounted on the boiler by means of eight cast-iron brackets, the
height of which is so arranged as to place such a distance between the boiler
and the engine that, the communication of heat shall not be considerable.
To this plate are bolted (in the ordinary manner) the steam cylinder, the
upper slides which guide the cross head or coupling of the piston rod and
connecting rod, and the feed pump; the latter is placed in an inclined
position and is actuated by a circular excentric mounted on the shaft. Lastly,

page_text: I may remark that the driving shaft is provided with a fly wheel and pulley
at each extremity, in order to equalize the torsion of the shaft from whichever
side the power may be transmitted.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Davies in the Great Seal Patent Office on the 5th
September 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of Middlesex; and
No. 87, St. Vincent Street, in the City of Glasgow, Civil Engineer and Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of March, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said George Davies, Her special licence that I, the said George Davies,
my executors, administrators, and assigns, or such others as I, the said
George Davies, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN THE CONSTRUCTION OF PORTABLE STEAM ENGINES," (a communication
to me from abroad by Isidore Nillus, the younger, of Paris, Machine
Maker,) upon the condition (amongst others) that I, the said George
Davies, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, 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 George Davies, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following.
statement in writing, and on reference to the accompanying Sheet of Drawings,
that is to say:-
The Invention which forms the object of the present application is

page_text: characterised by the construction of a system of portable steam engine,
which offers the same economical advantages and ease of working as the best
fixed engines. The relatively small dimensions of portable steam engines
render very
difficult the construction of a good boiler having a furnace large
énough and a sufficiently extended heating surface without being obliged to
increase the intensity of the fire under conditions very prejudicial to the
economy of the combustible and to the preservation of the boiler itself.
Besides, by the superposition of the working parts of the engine and the
boiler serious difficulties are experienced in conveniently isolating the working
parts, and protecting them from the effects of too great a heat, and at the
same time giving them the necessary connection and solidity. It is to solve
these principal difficulties, as well as various others hereafter alluded to, that
the following combination and arrangement have been designed:-The boiler
is composed principally of a horizontal cylindrical body and a vertical body,
the lower part of which contains the furnace, and which rising considerably
forms a vast steam chest. The interior of the outer casing contains the.
furnace, a longitudinal flue, together with fire tubes, and a smoke box, to
which the chimney is connected externally. This arrangement allows a
greater traverse to the products of combustion than those ordinarily employed..
The heated gases and flames (which are not so liable to be extinguished as
when they enter tubes of small diameter) circulate through the boiler tubes
or flue, the heating surface of which is considerable. At its extremity these
gases rise and pass through tubes, which conduct them towards the front of
the engine into the smoke box, which is connected to the chimney by a
conduit which passes through the steam chest. Thus the utilization of the
heat of the products of combustion is as complete as possible, and moreover
the latter part of their passage is utilized for drying the steam contained in
the reservoir or steam chest, whence it is taken away directly to supply the
cylinder. The plate which serves as a base for all the engine is mounted on
the boiler by means of eight cast-iron brackets, the height of which is so
arranged as to place such a distance between the boiler and the engine that
the communication of heat shall not be considerable. To this plate are bolted
(in the ordinary manner) the steam cylinder, the upper slides which guide
the cross head or coupling of the piston rod, and the connecting rod, and the
feed pump; the latter is placed in an inclined position, and is actuated by a
circular excentric mounted on the shaft. Lastly, I may remark that the
driving shaft is provided with a fly wheel and pulley at each extremity, in
order to equalise the torsion of the shaft from whichever side the power may
be transmitted.

page_text: Such being the nature and object of the said Invention for " Improvements.
in the Construction of Portable Steam Engines," I will now proceed to
describe more in detail the manner in which the same is to be or may be
performed, or carried into practical effect, and in order that the same may be
distinctly understood I have annexed hereunto a Sheet of Drawings illustrative
thereof, and have marked the same with figures and letters of reference
corresponding with those in the following explanation thereof, that is to.
say:-
Figure 1 represents a side elevation of this portable steam engine, the boiler
being shown in longitudinal section, and the engine (properly so called) in
exterior view; Figure 2 is a general plan view; Figure 3 is an exterior view
of the end furthest from the opening of the fire-grate; Figure 4 is a partial
transverse section through the centre of the grate. The boiler is composed
principally of a horizontal cylindrical body A, and of a vertical body B,
of which the lower part limits the fire-grate, and which forms as it rises
considerably a vast reservoir of steam. The inside of the exterior body.
encloses the fire-grate (which I prefer being of steel plate), a flue D, several
tubes E, and a smoke box F, to which is joined externally the chimney G.
This arrangement allows a much greater traverse to the products of com-
bustion than those ordinarily in use, where the products of the fire-grate pass
immediately through tubes which extend from the fire-grate and escape directly
into the smoke box placed at the extremity opposite the boiler. Here the
warm gas and the flames (which are not so liable to be extinguished as when
they are forced to enter narrow tubes) circulate in the flue D, in which the
heating surface is considerable. At its extremity these gases rise and pass
through the tubes E, which carry them back again towards the front of the
engine into the smoke box, which is connected to the chimney by a pipe
passing through the steam reservoir. Hence the utilization of the heat from
the products of combustion is as complete as possible, and besides, the
extremity of their passage through the pipe F¹ is utilised for drying the steam
contained in the reservoir, whence it is taken directly by the feed pipe to the
cylinder.
Various experiments have shown that the hourly consumption of the
fuel per horse-power was but 4 lbs., which is a very good result for the
portable steam engine; the weight of water evaporated for every two pounds
of coke has been constantly eighteen pounds, although this water has been
taken at a temperature of 46° Fahrenheit. In general it may be remarked
that every square or cubical form is avoided in this boiler, in which all the
parts, and especially the fire-grate, are cylindrical, so as not to require stays.

page_text: Every part is accessible for cleaning by aid of the ordinary man-holes, and
the principal body is itself closed at the end opposite the fire by an end piece
A fixed by means of bolts, which can be easily taken out when it is desired to
inspect that extremity of the boiler. As for the mechanism which composes:
the engine it presents all the peculiarities which distinguish the most complete
and perfect engines, except that the framework H, on which all the other
parts exclusively depend, presents a special construction adapted to this class.
of engine, in which the driving shaft cannot have (as is well known) any
external support. Having discovered that sufficient notice is not taken in
ordinary practice of this circumstance, which causes a want of truth, and often
occasions the breakage of this shaft, the Inventor has given to the plate H
the construction shown specially in the plan view, Figure 2, and which furnishes
four points of support, or four pedestals, between which are supported the
crank of the driving shaft I', and the different driving accessories of the
mechanism. The plate H, which serves as a base for all the moving parts, is
mounted on the boiler by means of eight cast-iron brackets J, the height of
which is so arranged that there may be such a distance between the boiler
and the engine that the communication of heat may not be injurious. To the
plate are bolted in the ordinary manner the steam cylinder K, the upper
slides L, which guide the cross-head which couples the piston to the connecting"
rod M, and the feed pump N. This last is placed in an inclined position and
driven by a circular excentric mounted on the shaft. On the slides is mounted
the frame of the governor O, receiving its motion from the driving shaft by
means of two pulleys O¹ and 0%, and a pair of bevil wheels O³.
I will now call attention to the distribution of. steam in the cylinder which
comprises all the details necessary to produce a variable expansion at will.
To this end the steam box P encloses a principal slide valve (pierced with
openings) which has its particular driving excentric Q, and on the back of
this slide are placed two register plates mounted by right and left hand screw
threads on a rod R, which receives from another excentric R₁ a rectilinear
alternating movement; the junction of the rod R with the bar of the excentric
is effected in such a manner as to allow it to turn freely on its own axis when
it is acted upon by means of the cross pin a, and when it is made to turn
thus in order to vary the expansion a small index 6 mounted on the top of
this rod and in a mortice in the cross head c indicates by its displacement in
front of a graduated scale the degree of expansion employed, and at which
it is wished to cut off the steam. I will remark that the driving shaft is
furnished at its two extremities with two fly wheels S, and two driving pulleys T
in order to equalise the torsion of the shaft froin, whichever side the driving

page_text: power may be transmitted. The steam is taken into the valve box P through
its upper part by a pipe U which rises therefrom and descending by a curve
of large radius is connected to the steam regulating tap V fitted directly on
the reservoir or steam chest of the boiler; the position of this tap and the
elevated form of the pipe U are combined with a view to stop the return of
the condensed vapors into the valve box. It is on the tube of the valve box
where the steam pipe is fitted that the throttle valve is placed, the opening of
which the governor is intended to regulate. The escape of the steam is as is
usual by a closed channel connected to the cylinder, and which leads first to
a cylindrical vessel X placed between the boiler and the engine, and through
which passes and repasses the pipe e, by which the feed pump forces the cold
water into the boiler; this vessel X performing the duty of heating the feed
water the exhaust steam circulates therein at first, and then flows away
through the exterior pipe which rises and opens into the chimney to increase
the draught.
Lastly, there remains to mention (with reference to the boiler) that there
are two safety valves placed on a single pipe mounted on the outside of the
fire-box.
"
Having now described the nature and object of the said Invention for
Improvements in the Construction of Portable Steam Engines," together
with the manner in which the same is to be or may be performed or carried
into practical effect, I would remark in conclusion that I claim as the Invention
communicated to me by the said Isidore Nillus, the younger,-
Firstly, the combination of the boiler, flue, and fire tubes in their application
to portable steam engines.
Secondly, the arrangement of the mechanism of the engine and its plate
with four bearings.
Lastly, the general arrangement and connection of the boiler, and the
moving mechanism, and the adjustment of the various parts applicable to
the construction of improved portable steam engines of any power and of any
dimensions.
In witness whereof, I, the said George Davies, have hereunto set my
hand and seal, this Thirtieth day of August, in the year of our Lord
One thousand eight hundred and sixty-six.
GEORGE DAVIES. (L.S.)