IMPROVEMENTS IN LOCOMOTIVE STEAM ENGINES
Year: 1858

page_text: LETTERS PATENT to Alexander Miller, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN LOCOMOTIVE STEAM ENGINES."-A communication from William Miller,
of Chicago.
Sealed the 31st December 1858, and dated the 11th October 1858.
PROVISIONAL SPECIFICATION left by the said Alexander Miller at
the Office of the Commissioners of Patents, with his Petition, on the
11th October 1858.
I, ALEXANDER MILLER, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN LOCOMOTIVE STEAM ENGINES," a communication from William Miller,
of Chicago, to be as follows, that is to say:-
This Invention relates to a simple and effective mechanical arrangement
for varying the action of the blast pipe of locomotive steam engines so as to
suit its effect to the varying kinds of work which the locomotives have to
perform. In this arrangement the top of the combined blast pipe taking the
discharged steam from both cylinders, is fitted with an eccentrically disposed
horizontal disc plate to form the bearing surface for a rotatory variable blast
chamber. This chamber is formed with four or other number of tapered or
conical blast thoroughfares disposed annularly round the centre on which the.
chamber rotates. It is set upon a vertical stud centre carried in the centre
of the fixed disc plate beneath. Each blast thoroughfare in this chamber is.
of the same diameter at its lower wider end, but each tapers to a different

page_text: smaller diameter at the top where the steam escapes. The rotatory blast
chamber is fitted on its lower side with a toothed spur-wheel gearing with a
corresponding spur wheel fast on the lower end of a vertical shaft passing down
through the smoke box. The upper end of this shaft is connected by bevil
gearing with the front end of a horizontal shaft, which is carried in bearings on
the barrel of the boiler running back to the engine driver's platform, where a
winch handle is attached for turning it. With this arrangement the driver
can at any time bring any one of the blast passages in the rotatory chamber
directly over the blast pipe beneath, so as at once to suit the blast to the
actual work which the engine has to do. The blast passages are arranged in
regular gradations of diameter at the top, so that the driver can pass from one
to another until he arrives at the size he requires. The bottom diameters of
the passages are all somewhat larger in diameter than that of the blast pipe
beneath, so that the escaping steam may have a free escape into the passage
above without tendency to lateral escape at the disc surface. The stationary
disc of the blast pipe may have passages through it to correspond with the
unengaged passages in the rotatory chamber, and thus allow of draught
thoroughfares through the unengaged passages, and prevent any retardation
of the flue draught. This arrangement presents peculiar facilities for the
driver's adjustment of his blast to suit inclines, variable loads, fuel, and other
circumstances.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Miller in the Great Seal Patent Office on the
11th April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MILLER, of Glasgow, in the County of Lanark, North Britain, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of October, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Alexander Miller, Her special license that I, the said Alexander
Miller, my executors, administrators, and assigns, or such others as I, the
said Alexander Miller, my executors, administrators, or 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

page_text: make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "Im-
PROVEMENTS IN LOCOMOTIVE STEAM ENGINES," a communication from William
Miller, of Chicago, upon the condition (amongst others) that I, the said
Alexander Miller, 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 Alexander Miller, do hereby declare
the nature of my 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, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
The said Invention relates to a simple and effective mechanical arrangement
for varying the action of the blast pipe of locomotive steam engines so as to
suit its effect to the varying kinds of work which the locomotives have to
perform. In this arrangement the top of the combined blast pipe taking the
discharge steam from both cylinders, is fitted with an eccentrically disposed
horizontal disc plate, to form the bearing surface for a rotatory variable blast
chamber. This chamber is formed with four or other number of tapered or
conical blast thoroughfares, disposed annularly round the centre on which the
chamber rotates; it is set upon a vertical stud centre, carried in the centre of
the fixed disc plate beneath. Each blast thoroughfare in this chamber is of
the same diameter at its lower wider end, but each tapers to a different
smaller diameter at the top where the steam escapes. The rotatory blast
chamber is fitted on its lower side with a toothed spur wheel gearing with a
corresponding spur wheel fast on the lower end of a vertical shaft passing
down through the smoke box. The upper end of this shaft is connected by
bevil gearing with the front end of a horizontal shaft which is carried in
bearings on the barrel of the boiler, running back to the engine driver's plat-
form, where a winch handle is attached for turning it. With this arrange-
ment the driver can at any time bring any one of the blast passages in the
rotatory chamber directly over the blast pipe beneath, so as at once to suit
the blast to the actual work which the engine has to do.
The blast passages
are arranged in regular gradations of diameter at the top, so that the driver
can pass from one to another until he arrives at the size he requires. The
bottom diameters of the passages are all somewhat larger in diameter than
that of the blast pipe beneath, so that the escaping steam may have a free

page_text: escape into the passage above without a tendency to lateral escape at the disc-
surface. The stationary disc of the blast pipe may have passages through it.
to correspond with the unengaged passages in the rotatory chamber, and thus
allow of draught thoroughfares through the unengaged passages, and prevent
any retardation of the flue draught. This arrangement presents peculiar
facilities for the driver's adjustment of his blast to suit inclines, variable loads,
fuel, and other circumstances.
And in order that the said Invention may be properly understood, I shall
now proceed to describe the several Figures on the explanatory Sheet of
Drawings which I have hereunto appended for the purpose of showing certain
modifications under which the improvements may be judiciously carried out
in practice, that is to say :-
Figure 1 on the accompanying Drawing is a sectional end view or elevation
of one modification of the improvements; Figure 2 is a plan corresponding to
Figure 1; Figure 3 is a sectional end elevation of another arrangement of
apparatus for regulating the action of the blast pipe in locomotive engines;
and Figure 4 is a corresponding plan.
The construction and arrangement of the boiler A of the engine, and smoke
box B, the steam pipe C, the cylinder D, and the blast pipe E, do not differ
from those in ordinary use, and need not be more particularly referred to.
The upper extremity of the blast pipe E is made with a flange, to which is
bolted the blast chamber F; this chamber consists of a horizontal disc plate,
the periphery of which forms a toothed wheel G; the upper part of the blast
chamber is divided into four conical openings, which are arranged round the
central retaining bolt or stud centre on which the chamber is free to turn.
The openings H are by preference made of a conical figure; one of these
apertures correspond in diameter to the interior of the blast pipe, the other
three being respectively reduced in diameter, as shown in Figure 2 on the
accompanying Drawing. The variation in the size of these vertical openings
enables the engine driver to contract or enlarge the passage through the blast
pipe as required, the eccentric arrangement of the blast chamber admitting
of the tubular openings H, being brought successively over or in a right line
with the interior of the blast pipe E. Parallel to the axis of the blast pipe is
arranged a vertical shaft I; the lower extremity of this shaft works in a
footstep bearing on the upper side of the valve chest or other convenient
place; the upper part of the shaft works in a collar bearing just inside the
boiler shell A, the extremity of the shaft passing out through the shell, and
having keyed thereto the bevil pinion J; a spur wheel K is fitted to the
shaft I so as gear with the wheel G, and thus cause the blast chamber F

page_text: to rotate when the shaft is put in motion. The pinion J gears with a corre-
sponding pinion L on the extremity of a horizontal shaft, which extends along
the exterior of the boiler, and terminates in a handle that is within con-
venient reach of the engine driver. By turning the operating handle, the
engine driver is enabled to bring the openings H successively over the blast
pipe E, and in this manner he can check the velocity of the blast when the
engine is running upon a level or with a reduced load; and, on the contrary,
he can increase it when the full power is required, as in ascending inclines or
when a heavier load is to be put in motion.
The modification shown in Figures 3 and 4 on the accompanying Drawing
differs in the arrangement of the mechanical details, by means of which the
blast chamber is caused to rotate upon its central stud.
The arrangement of the boiler, the smoke box, steam pipe cylinders, and
blast pipe, all correspond to the similar parts in Figures 1 and 2, and are
marked with corresponding letters of reference. The blast chamber F, which
is similar in its form to the modification herein-before described, rotates upon
the disc G, which is formed on the upper end of the blast pipe E. The lower
edge of the blast chamber has four inclined projecting parts I formed thereon,
the spaces between these projections forming so many recesses or notches on
the periphery of the lower edge. An arm J turns loosely on the central stud,
which projects through to the under side of the disc G; the free extremity of
this rotating arm carries a stud, on which is centred the oscillating arm K,
the central extremity of which is connected to the link L, the two free
extremities of the arm being alternately in contact with the periphery of the
lower edge of the blast chamber; the other extremity of the link L is attached
to the lever arm M, which is fast to the vertical shaft N; the upper extremity.
of this shaft passes out through the smoke box, and to it is fitted a short lever
arm O, which extends along to the backward end of the engine, where it has
fast to it a lever handle, by means of which the moving parts of the apparatus
are actuated. Upon the engine driver moving the handle backwards, the heel
of the oscillating arm K comes in contact with the periphery of the blast
chamber F; this raises the other extremity of the arm so as to release it
from the notch or recess formed by its contiguous projection I; this move-
ment or release of the arm K allows it to slide round the periphery of the
blast chamber a distance corresponding to the backward traverse of the
actuating horizontal rod, the heel or upwardly turned end of the arm passing
freely over the projections I. The forward movement of the actuating handle
causes the front end of the arm K to catch against the end of the nearest
projection I, and thus draw the blast chamber F round the fourth part of a

page_text: revolution, so as to bring one of the tubular apertures H over or in a line with
the blast pipe E. The traverse of the actuating rod is thus so arranged that
every to-and-fro motion of the handle brings the tubular apertures H succes-
sively over the blast pipe E. In this manner the engine driver is enabled to
control the emission of the blast, so as to adapt it to the load or nature of
the line on which the engine is travelling, and thereby economise the fuel
when a diminished draft is sufficient.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion
to describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of the Invention; but what I
consider to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of the mechanical arrange-
ment or apparatus for regulating the blast in locomotive steam engines, as
herein-before described and shown in the accompanying Drawings.
Second, the system or mode of controlling and regulating the emission of
the blast in locomotive engines, by means of the mechanical apparatus
herein-before described and shown in the accompanying Drawings, or any
mere equivalent therefor.
Third, the application and use of a rotatory blast chamber in locomotive
engines, together with the mechanical arrangements for actuating the same,
for the purpose of bringing the tubular apertures successively over the blast
pipe of the engine, as herein-before described.
In witness whereof, I, the said Alexander Miller, have hereunto set
my hand and seal, this Eighth day of April, One thousand eight
hundred and fifty-nine.
ALEXANDER MILLER. (L.S.)