IMPROVEMENTS IN STEAM ENGINE BOILERS, AND IN STEAM PROPELLING MACHINERY
Year: 1851

page_text: MILLS, of Southampton, in the County of Hants, Engineer, send grecting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Iler
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-second day of
November, One thousand eight hundred and fifty-one, in the fifteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said George Mills, my exors, admors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said George Mills, my exors,
adiiors, and assigns, or such others as I, the said George Mills, my exors,
adiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN STEAM
ENGINE BOILERS, AND IN STEAM PROPELLING MACHINERY;" in which said Letters
Patent is contained a proviso that I, the said George Mills, shall cause a par-
ticular description of the nature of my said Invention, and in what manner the
same is to be performed, by an instrument in writing under my hand and
seal, to be enrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Mills, hereby declare that the nature of my said Invention, and in

page_text: what manner the same is to be performed, are fully described and ascertained
in and by the present Specification thereof, reference being had to the Drawings
hereunto annexed, that is to say:-
Firstly, my Invention, in so far as regards steam engine boilers, consists in
the improvements represented in Figures 1 to 10, both inclusive.
Figure 1 is an elevation, partly in section, of a steam boiler constructed for
marine purposes, and with a special view, therefore, to including in a given
space the largest possible amount of heating surface combined with strength
and durability. The boiler is tubular, and the tubes a, a, are flat sided and
narrow, with hemispherical indentations or corrugations, two or more (b, b,)
formed in them, as separately represented on an enlarged scale in Figure 9.
These indentations serves two purposes, first, by bringing the indented parts on
one side of each tube opposite to the indented parts of the opposite side, so that
the two shall touch and abut against each other; they serve as so many
internal stays to the tube, and impart great additional strength thereto. And
second, when a number of such tubes are arranged in the above position, the
hollow sides of the indentations form water spaces (running in the reverse
direction to the tubes themselves), which add considerably to the amount of
evaporative surface. The flues are bent and overlapped at the ends, or at top
and bottom, as the case may be, and firmly rivetted together, as shewn in
Figures 8 and 9; or they may be united at these points by a curved joint piece,
as shown in Figure 10, or by common angle iron in the usual manner.
Figure 2 is a transverse section of the boiler represented in Figure 1, shewing
an elevation of one of the flues, with the indentations or corrugations b, b.
Figures 3 and 4 are transverse sections exemplifying a modification of the
preceding mode of construction. In Figure 4 the tubes are indented or corru-
gated throughout their whole length, but those in Figure 3 for a portion only of
their length, the corrugated parts forming on the hollow side longitudinal water
chambers, which are made to meet, as shewn in section, Figure 1. The mode
of firing amidship adopted in Figures 3 and 4 is intended for vessels of large
power, where there is sufficient space to get a well ventilated stoke-hole.
Figure 5 is an elevation, partly in section, of a marine steam boiler, having
two tiers or sets of flues c, c, placed one over the other, and lying horizontally
over the furnaces, and connected at the ends in the manner before described.
This arrangement is intended to be applied where the height of the boiler is
no object.
Figure 6 is a transverse section of Figure 5, shewing an elevation of one
of the flues, and the arrangement of the indentations or hemispherical
chambers d, d.

page_text: Figure 7 shows two transverse sections of a boiler constructed with two sets
of flues, as above described, having the flues formed of plates of iron, indented
or corrugated, and arranged in the same manner as in Figures 3 and 4..
The section A of Figure 7 shows no smoke box or door, but a water space e
placed between the flue fleading to the uptake and the front of the boiler, an
arrangement which is adopted wherever space and other circumstances will
permit. The flues would in that case be cleaned either from the back of the
furnace or from the uptake.
Secondly, my Invention, in so far as it regards steam propelling machinery,
consists in the different improved arrangements represented in the, Drawings
marked No. 1, No. 2, No. 3, and No. 3". No. 1 is a plan, and No. 2 a section on
the line A, B, of an arrangement which is more particularly applicable to screw
propelled ships of war. Here, in order to keep the machinery low down, the
cylinders are laid horizontally; but the better, to ensure uniformity of motion,
they are set at right angles to one another, or thereabouts, and the power is
transmitted through a vertical crank shaft, with one crank only, to a bevil wheel
and pinion, and thence to the screw propeller shaft, whereby a great speed of
the screw propeller is obtained (at comparatively a disproportionate loss of power.)
P, P, P, represents the bed plate of the engines; A, A, the steam cylinders;
B, B, the pistons, which are of the chambered or box form of construction, fully
shewn in all its details in Figure No. 2. C, C, are the connecting rods of the
pistons; D, D, slide valves and cases; E, E, steam ports; F, F, excentric
rods; G, G, exhaust passages; H, air pump; I, air pump trunk; K, L, L, alr
pump connecting rods; M, condenser; N, N. discharge valves, immediately
beneath which are the usual foot valves; 0, 0, discharge pipes; Q, crank pin;
R, return crank for driving the excentric; S, S, the bevil wheel on the crank
shaft; V, the pinion; U, the screw shaft; and W its pillow block. a, a, arc
the throttle valves, and g, g, the handles thereof; b, b, the blow through valves,
and h, h, their handles; c, c, steam pipes; e, e, injection valves, with handles f,f;
d is the starting wheel, and i the disengaging handle.
Another horizontal arrangement, applicable as well to merchant vessels as to
ships of war, is shewn in the Drawing No. 3, Figure 1 being a plan, and
Figure 2 a longitudinal section on the line A, B. 1, 1, are the steam cylinders;
2, condenser, with double-acting air pump underneath; 3 (Figure 2), the air
pump; 4, vertical crank shaft with one crank (as in the arrangement first
described); 5, crank; 6, bevil wheel; 7, pinion which transmits the motion to
the propeller shaft; 8, cross bracket. which supports the crank and pinion
shafts 9, air pump rods; 10, connecting rods; 11, piston rod guides; and 12,
steam nozzles. The Drawings marked No. 3b shew an arrangement which

page_text: differs from the preceding chiefly in the lesser angle at which the engines are
set in regard to each other. A is an elevation of the machinery partly in
section; and B a longitudinal section; C is a longitudinal section, with the air
pump in a reverse position to that represented in A and B.
And having now described the nature of my said Invention in the several
parts thereof, and in what manner the same is to be performed, I declare that
the improvements which I claim are as follows:-
First, I claim the employment in steam engine boilers of flat-sided flues
having indentations or corrugations (two or more) therein, touching and
abutting against one another on the protuberant sides, and forming water spaces
on the hollow sides, as before described.
Second, I claim the improved arrangements of steam propelling machinery
respectively represented in No. 1 of the Drawings annexed, in No. 2 and No. 3,
and in No. 3, cach in the peculiar arrangement and combination of known
parts of which it consists.
And, third, I claim the constructing of the pistons of steam engines of the
chambered or box form represented in the Drawings No. 1 and No. 2, and
before described.
In witness whereof, I, the said George Mills, have hereunto set my hand
and seal, this Twenty-second day of May, in the year of our Lord One
thousand eight hundred and fifty-two.
GEORGE (L.S.) MILLS.
AND BE IT REMEMBERED, that on the Twenty-second day of May, in
the
year of our Lord 1852, the aforesaid George Mills came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also. the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.