Improvements in Marine and other Steam Engines.
Year: 1893

page_text: The decision of the Chief Examiner, acting on behalf of the Comptroller, of the
18th day of September 1895, allowed, under Section 18 of the Patents, &c.
Act, 1883, an Amendment of this Specification.
Date of Application, 9th Sept., 1893
Complete Specification Left. 8th June, 1894-Accepted. 14th July, 1894
PROVISIONAL SPECIFICATION.
Improvements in Marine and other Steam Engines.
We, WALTER BROCK, of the Firm of Denny and Company, of Dumbarton in
the County of Dumbarton, North Britain, Engineer, and JAMES WEIR, of Holm
Foundry, Cathcart, in the County of Renfrew, North Britain, Engineer, do
hereby declare the nature of this invention to be as follows, that is to say:
-
Our said invention comprises further modifications and extensions of improve-
ments or arrangements described in our Patent Specification No. 8095 of 1891, as
applicable to steam engines ordinarily working with two or more stages of
expansion, and having for object to obtain greater relative efficiency and economy
of fuel when such engines are worked so as to yield less than their full power,
than is possible with previously existing arrangements of such engines.
And whereas according to our said earlier Specification one additional set of
pipes or passages or valves was to be provided to allow of the engines being
worked for one lower power differently from the working for the maximum power,
by our present invention additional pipes or passages and valves are to be provided
to allow of the engines being worked efficiently and economically to yield the
maximum power or to yield either or any of two or more smaller powers. Our
improved arrangements not only give more choice as to the precise power to be
economically developed when less than the maximum power is required; but also
allow of intermediate powers being obtained with comparatively small deviation
from the best economical efficiency.
:
In carrying out our present invention in the case of engines working as compound,
that is with two stages of expansion, for the maximum power, we employ three
cylinders. Two of the cylinders of unequal sizes are both supplied with boiler
steam, that is high-pressure steam for the maximum power, the second stage of
expansion taking place in the third or low-pressure cylinder which is larger than
the other two combined. For a somewhat lower power, high-pressure steam is
supplied only to the cylinder of middle size, the smallest cylinder being used as a
second low-pressure cylinder, or being rendered ineffective by means of a by-pass
valve or by being shut off. And for a still lower power, high-pressure steam is
supplied only to the smallest cylinder, a second stage of expansion taking place in
the middle cylinder and a third in the low pressure cylinder.
In another modification of engines working as compound for the maximum power,
we employ four cylinders of graduated sizes. Denoting the cylinders in increasing
order as, A, B, C, D; the two smallest, A, B, are supplied with high-pressure
steam, and the two largest, C, D, act as low-pressure cylinders, for the maximum
power. For a somewhat lower or intermediate power, the second cylinder, B, is

page_text: supplied with high-pressure steam, and the 'larger cylinders, C, D, act as inter-
mediate or second-stage, and low-pressure or third-stage cylinders. The smallest
cylinder, A, may either work with the intermediate or low-pressure cylinder, or be
rendered ineffective by means of a by-pass valve, or by being shut off.
For a still
lower power the engines are worked as quadruple-expansion or four-stage engines,
high-pressure steam being supplied only to the smallest cylinder, A.
In the case of engines working as triple-expansion engines for the maximum.
power,, we employ four cylinders, A, B, C, D, of graduated sizes. For the
maximum power high-pressure steam is supplied to the two smallest cylinders, A, B,
the third cylinder being worked as an intermediate or second-stage cyliuder, and
fourth cylinder, D, as a low-pressure or third-stage cylinder. For somewhat lower
power high-pressure steam is supplied only to the second cylinder, B, whilst the
smallest, A, is combined with the third, C, or fourth, D, or rendered ineffective
by means of a by-pass valve or by being shut off. For still lower power the
engines are worked as quadruple-expansion engines.
When in any of the cases a power is required differing from any of the precise
powers obtainable in 'the manner herein before indicated, the nearest so obtainable
power is arranged for, and in addition the distribution or expansion valve gear is
adjusted to suit the desired power, a by-pass valve or a shutting-off valve being
also available if required..
Dated this Eighth day of September 1893.
EDMUND HUNT,
Applicants' Agent.
Improvements in Marine and other Steam Engines.
We,
WALTER BROCK, of the Firm of Denny and Company, of Dumbarton, in
the County of Dumbarton, North Britain, Engineer, and JAMES WEIR, of Holm
Foundry, Cathcart, in the County of Renfrew, North Britain, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
that is to say :-
Our said invention comprises further modifications and extensions of improvements
'or arrangements described in our Patent Specification, No. 8095 of 1891, as
applicable to steam engines ordinarily working with two or more stages of expansion
and having for object to obtain greater relative efficiency and economy of fuel,
when such engines are worked so as to yield less than their full power, than is
possible with previously existing arrangements of such engines.
And whereas according to our said earlier Specification one additional set of
pipes or passages and valves was to be provided to allow of the engines being
worked for one lower power, differently from the working for the maximum power,
by our present invention additional pipes or passages and valves are to be provided
to allow of the engines being worked efficiently and economically to yield the
maximum power, or to yield either or any of two or more smaller powers. Our
improved arrangements not only give more choice as to the precise power to be
economically developed when less than the maximum power is required; but also
allow of intermediate powers being obtained with comparatively small deviation
from the best economical efficiency.
Our improvements are applicable to various arrangements of marine or other
steam engines, and on seven accompanying sheets of explanatory drawings we show
scme applications as examples, from which our invention and the manner of
performing the same may be properly understood.
On each of Sheets, 1, to, 6, of the accompanying drawings a single example is

page_text: shown; bụt in every case only as much of the engine is shown as-is considere.l-
necessary in explaining the improvements; and it is to be understood that parts
not described or delineated are to be constructed or arranged in any suitable known
manner. All the engines shown are inverted-cylinder screw-propeller engines.
On Sheet, 7, of the drawings are shown modifications of the valve details.
On Sheet, 1, Figures, 1 and 2, are a sectional plan and a side elevation of
Example No. 1, Figure, 3, being a transverse vertical section of a portion of the
valve details. This example comprises three cylinders, A, B, C, connected to
three cranks.
On Sheet, 2, Figures, 4, 5, and 6, are a plan with the smallest cylinder, A,
removed, a side elevation, and a transverse vertical section of Example No. 2,
which differs from No. 1, in having three cylinders, A, B, C, connected to two
cranks, cylinder, A, being placed tandem to cylinder, B.
On Sheet, 3, Figure, 7, and, 8, are a sectional plan and a side elevation of
Example No. 3, Figure, 9, being a transverse vertical section of a portion of the
valve details. This example comprises four cylinders, A, B, C, D, connected to.
four cranks.
On Sheet, 4, Figures, 10, and, 11, are a plan and a side elevation of
Example No. 4, Figure, 12, being a transverse vertical section of a portion of the
valve details. This example differs from No. 3, in having cylinder, A, tandem
to, B, and in being arranged for three cranks.
On Sheet, 5, Figures, 13, and, 14, are a sectional plan and a side elevation of
Example No. 5, Figure, 15, being a transverse vertical section of a portion of the
valve details. This example comprises four cylinders, A, B, C, D, connected to
four cranks.
On Sheet, 6, Figures 16, and 17, are a sectional plan and a side elevation
of Example No. 6, Figure, 18, being a transverse vertical section of a portion of
the valve details. This example differs from No. 5, in having cylinder, A, tandem
to, B, and in being arranged for three cranks.
On Sheet, 7, Figures, 19, to 22, show one modification of valve details, and
Figures, 23 to 25, show another.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated. The letters, A, B, C, D, mark
cylinders, the sizes of which are graduated in the order of the letters, the
cylinder, A, of each set being the smallest.
As shown on Sheets, 1, to, 6, the valves by the adjustment of which the working
of the engines is altered for the various powers, are screw-down disk valves, of a
usual construction, and are distinguished by numerals. In every case valve, 1, is
for admitting high-pressure or boiler steam to cylinder, A; valve, 2, for admitting
high-pressure steam to cylinder, B; valve, 3, for exhausting from cylinder, A, to
cylinder, C; valve, 4, for exhausting from cylinder, A, to cylinder, B; valve, 5,
for leading steam from valve casing of the low-pressure cylinder (C or D) to that
of cylinder, A; valve, 6, for exhausting from cylinder, A, directly to the condenser ;
passages, 7, for exhausting from cylinder, C, or, D, to the condenser; valve, 8, for
leading steam from valve casing of cylinder, C, to that of cylinder, D; valve, 9,
for exhausting from cylinder, C, to cylinder, D.
In the case of engines like Examples, 1, and, 2, working as compound,—that is
with two stages of expansion, for the maximum power, we employ three
cylinders, A, B, C. Two, A, B, of the cylinders, of unequal sizes, are both
supplied with boiler steam, that is high-pressure steam, for the maximum power-
through the valves, 1, and, 2, (Figures, 3, and 6) from the steam inlet, S, to the
distribution valves, E, F, for these cylinders. For a somewhat lower power, high-
pressure steam is supplied only to the cylinder, B, of middle size, the smallest
cylinder, A, being used as a second low-pressure cylinder, or being rendered
ineffective by means of a by-pass valve or by being shut off. For this power,
valves, 1, 3, and 4, are closed, and cylinder, A, is either inoperative or is worked
by steam admitted by valve, 5, from the valve casing of cylinder, C, valve, 6,
:

page_text: being also opened. For a still lower power high-pressure steam is supplied,
through valve, 1, only to the smallest cylinder, A, valves, 2, and, 3, being closed, and
valve, 4, opened, a second stage of expansion taking place in cylinder, B, and a
third in cylinder, C.
In another modification of engines working as compound triple-expansion, or with
two three stages of expansion for the maximum power, we employ four, cylinders,
as in Examples, 3, and 4, the cylinders being marked, A, B, C, D, in the order of
their increasing sizes. For the maximum power the two smallest cylinders, A, B,
are supplied with high-pressure steam through valves, 1, 2, and the two largest, C, D,
act as intermediate and low-pressure cylinders-valve, 3, being also open, and
valves, 4, 5, and 6, closed. For a somewhat lower or intermediate power, the
second cylinder, B, is supplied with high pressure steam, and the larger
cylinders, C, D, act, respectively as intermediate or second-stage, and low-pressure
or third-stage cylinders. The smallest cylinder, A, may either work with the
intermediate cylinder, C, or low-pressure cylinder, D, or be rendered ineffective
by means of a by-pass valve or by being shut off. For a still lower power the
engines are worked as quadruple-expansion or four-stage engines, high-pressure
steam being supplied only to the smallest cylinder, A.
In the ease of engines working as triple expansion engines for the maximum
power we, also, employ-four cylinders, A, B, C, D, as in-Examples, 5, and, 6. The
relative sizes of the cylinders may be varied in different cases to suit different
arrangements of the parts of the engines; by way of example, however we may
state that in the case of engines such as Examples, 3, and, 4, in each of which four
cylinders are employed a set of sizes varying as the following numbers,-A-11,
B-20, C-67, and D-148, will be found to work satisfactorily.
In the case of engines working as compound engines for the maximum power we may
also employ four cylinders, A, B, C, D, as in Examples, 5, and 6.
When in the Examples, 5, and 6, valves, 1, 2, 3, 7 and, 8, are open and the others
shut, high-pressure steam is supplied to cylinders, A, B, and the whole works as a
triple-expansion compound engine for the maximum power.
When valves, 2, 5, 6 and 9, are open and the others shut, we have a triple-
expansion engine working at about one half the maximum power, high-pressure
steam being supplied to cylinder, B, and cylinder, A, being supplied with steam
from the valve casing of cylinder, D, by valve, 5, and exhausting to the condenser
by valve, 6. Cylinder, A, might, with suitable connections, be arranged to work
with cylinder, C, instead of, D.
When valves, 1, and, 4, and 9, are open, and all the others shut, the engine will
work as a quadruple-expansion engine, only cylinder, A, being supplied with high-
pressure steam, and the power developed being about one fifth of the maximum. If
when the engine is working in this condition, valve, 2, is slightly opened, the power
will be increased in proportion to the extent of opening, part of the steam then
working through four stages of expansion and part through three stages. If
valve, 2, is sufficiently opened, the piston of cylinder, A, will be put practically in
equilibrium, and will do no work, the engine as a whole then working as
triple-expansion engine, but with effective capacity ratios for the three stages
differing from those existing when valves, 2, 5, 6 and 9, are opened and the
others shut.
a
When in any of the cases a power is required differing from any of the precise
powers obtainable in the manier herein before indicated, the nearest so obtainable
power is arranged for, and in addition the distribution or expansion valve gear is
adjusted to suit the desired power, a by-pass valve or a shutting-off valve being also
available if required.
On Sheet, 7, of the drawings are shown modifications of valves which may be
adopted instead of the screw-down valves, 1, 2, etc., shown on Sheets, 1, to, 6
Figure, 19, is a section as at G-G and H-H in Figure, 22; and Figure, 20, is a
section as at J-J in Figure, 22. Slide valves, K, L, M, N, are substituted for
screw-down valves, the ports controlled by such valves being marked with numerals

page_text: corresponding to the screw-down valves of preceding modifications. The communi-
cating passages or pipes are substantially as in the preceding modifications, but
instead of the valves being applied at various parts of such pipes or passages they
are arranged so as to be all near together. The slide valves, K, L, M, N, are
movable by means of two spindles with screw hand wheels, P, Q; and in
connection therewith pointers and graduated plates may be applied to show the
various positions of the valves and the engine powers corresponding to such
positions. In Figures, 23, to, 25, another modification of parts with slide valves is
shown, the parts being distinguished with the same reference letters and numerals
rendering repetition of the explanations unnecessary. The construction and
arrangement of the valves and communicating passages may be varied in any
manner provided they are made capable of adjustment in a manner allowing of the
engines being worked to yield different powers substantially as hereinbefore
described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
In marine and other steam engines constructed for working with two or more
stages of expansion, adding in each case one or more extra cylinders, and providing
in connection with such cylinders extra passages and valves, so as to cause the
engines to yield different powers, by closing and opening particular valves for each
power, substantially in the manner and for the purposes hereinbefore described.
Dated this Seventh day of June 1894.
EDMUND HUNT,
Applicants' Agent.