Improvements in Steam, Gas and like Engines.
Year: 1899

page_text: Date of Application, 8th Nov., 1899
Complete Specification Left, 8th Aug., 1900-Accepted, 18th Oct., 1900
Improvements in Steam, Gas and like Engines.
I, GUSTAVE MAURICE DEMOULIN, of the Gare Maritime, Dieppe, in the Republic
of France, Railway Inspector, do hereby declare the nature of this invention
to be as follows:-
This invention has for its object improvements in balanced engines designed
to be driven by steam, gases or other convenient motive fluid acting either by
expansion or explosion.
The engines, as hereinafter described, are furnished with pistons moving in
opposite directions, and operating, according to the predetermined arrangement,
two or three cranks disposed at an angle of say 180°.
In order that my invention may be clearly understood I will describe the same
with reference to the accompanying drawing which shows various constructions
embodying my invention.
In Figure 1 the motor shaft is provided with three cranks, two, M' and M
being parallel, and the other, or middle, crank M being set at an angle of 180°
to the former.
Three pistons P, P1, P2 adapted for single or double action, are arranged to
operate the three cranks respectively while moving in their corresponding
cylinders CC C. During one piston stroke, the steam or other motive fluid
is admitted simultaneously at the top of piston P and below the pistons P¹ and P³,
and during the other stroke, it is admitted between the three pistons. If the
engine is single-acting, the steam is only admitted between the pistons, in which
case the pistons 1" and 1 may be of the plunger type.
If the compound system is adopted, the cylinders may advantageously be
arranged as shown in Figure 2 comprising two high-pressure cylinders ĦI',
and one low pressure cylinder L P, placed centrally above the former.
Figure 3 shows a similar type of engine, in which the three cranks M M¹ Mª
are operated by two pistons moving in inverse directions in a single cylinder C.
One of these pistons P operates the outer cranks M M by means of the rod t and
cross-head and suspended connecting rods B, while the other piston P¹ of the
plunger type, directly operates the middle crank M³, through the intervention
of the connecting rod ¹. The special feature of this engine and one which
constitutes an important part of the present invention is, that the engine is
made of the compound type having the following arrangement. The steam or
other motive fluid is first admitted to the space above the upper piston P, and is
thence conducted into the space situated between the pistons P and P¹ in which
latter space it acts by expansion only. This engine works in an oil bath or tank,
and a casing K completely surrounds the working parts thereof.
P
Figure 4 is a modification, in which the lower piston P¹ operates the outer
cranks M M by means of connecting rods B¹ B while the upper piston l' operates
the middle crank M. through the medium of a rod T, passing through the
piston P, and connecting rod B. A single slide-valve D mounted in the steam
chest is provided to effect, by means of ports a lb the distribution of the steam
or other motive fluid in the cylinder.

page_text: Figure 5 shows another modification embodying the combination of the general
arrangement shown in Figure I with the action of the machines shown in
Figures 3 and 4. Three cylinders C C C² arranged as shewn, are provided with
three pistons P P P which operate the cranks as follows:-that is to say, the
piston operates the middle crank M and the pistons P¹ the cranks M Ma;
the said piston I being double acting. The upper space of the cylinders C¹³ C*
normally communicates with the lower space of the cylinder C. The steam or
other fluid is admitted to the upper part of the cylinder C above the piston P,
into the space marked 1 and afterwards expands in space 2 between the three
pistons. A single slide-valve is sufficient to effect the admission of steam or the
like for all the three cylinders. The function however is not necessarily com-
pound, the steam may be admitted during one stroke to the piston l', and during
The other stroke, between the three pistons.
Figure 6 shows a modification embodying the principle of triple expansion,
the steam being admitted in succession to the spaces 1, 2 and 3.
Figure 7 shows a simplified arrangement of the engine illustrated by Figure 5,
and in which there are only two cylinders C C¹ and two cranks, M M¹ keyed at
an angle of say 180°. These cranks work in a closed casing containing an
oil-bath. The steam may be admitted in succession above the piston P then in
the free space between the pistons P and P¹, or it may be admitted only into
space 1 above the first piston and then be allowed to expand according to Woolf's
principle between the two pistons in the space 2. The centres of these two
pistons are disposed as close together as is possible so as to ensure better
equilibrium. To reduce wear the cranks are constructed as shown in Figure 10.
The two journals of the motor-shaft 00' which may be hardened and turned
to gauge are formed each with a disc K, K' in which engage the tapered ends BB₁
respectively of the crank pins M and M. These crank pins are secured in
position by nuts E and E, while centrally, they are joined together by an
arm A. The pins M M¹ are hardened and gauged and the connecting rods are
mounted thereon by means of bushes b and b formed integrally with the connect-
ing rods, but without adjustment for play.
To ensure a better equilibrium for the two engines shown in Figure 7, the
improved arrangement illustrated in Figure 8 for a double acting, or Figure 9
for a single acting engine, may be adopted. The pistons P P are provided
with additional weights and p, respectively disposed at one side thereof, so
as to face each other, in such a manner, that the centres of gravity G G of the
alternate parts will be brought into the same line y, parallel to the axes of the
cylinders, and as far as possible at equal distance from these axes. In this
manner, notwithstanding the slight overhanging of the pistons, an almost perfect
equilibrium may be obtained for all the alternative parts with but two cranks.
Dated this 8th day of November 1899

page_text: and in what manner the same is to be performed, to be particularly describe:i
and ascertained in and by the following statement :-
This invention has reference to steam engines partially or entirely balanced
and notably to the special disposition for obtaining the compound effects.
These machines are constructed with two or three cranks juxtaposed and keyed
at 180° adapted to be operated by pistons having a single or double action and
moving in opposite directions.
Figure 1 shows the general arrangement of a machine with two cranks.
The cylinders 1 and 2 are superposed and placed out of line their axes being
situated as closely together as possible owing to the special construction or
configuration of the crank-arm g. These two cylinders communicate with one
another through an orifice 35 at one of their extremities. The distribution of
steam is effected by means of the slide valve 16 disposed as shown.
The live steam from the steam valve is admitted through the orifice 31 to the
upper part of the cylinder 1 above the piston 11. During the upstroke of this
piston, owing to the particular arrangement of the slide valve 16, the steami
escapes through the orifices 31 and 32 and fills the space between the two pistons I'
and 21 where it acts by expansion. During the next stroke, while the pistons
approach each other, the steam having expanded between the two pistons escapes
into the condenser through the conduit 32 and orifice 33. Owing to the arrange-
ment of slide valve the exhaust-orifice 33 is closed by the lower cross har of the
valve when the orifices 31 and 33 are placed in communication through the
chamber between the lower and upper collars.
The operation of the steam is as follows: live steam is admitted over the
piston this steam expands during the following stroke in the large space
comprised between the two pistons, and is exhausted at the next stroke into the
condenser. The piston 1 is double acting and the piston 21 single acting.
The piston operates, through the intervention of connecting rods 5 and 6,
the two cranks 7 and 8 respectively of the motor shaft 10 which cranks are
connected together by the central arm 9 in the following manner:
The arm
(Figure 2) is in form of a disc of great thickness cut away at a and b to the
right of the trunnions 7 and 8 in such a manner as to permit of the widening of
the connecting rod heads; these cut away portions being circular and concentric
to the trunnions 9 and 8 thus leaving projecting portions c and d designed to
strengthen the arm 9 by curvilinear triangles eg and d f h for the purpose of
preventing it bending in the axial direction of the shaft.
A single eccentric 18 operates the valve 16 through the intervention of the
rod 17.
Figure 3 shows the type with 3 cranks which operate on the same principle
as that involved in the previously described engine. A double acting piston 1'
operates by its connecting rod 5 a central crank 9. Two single acting pistons 2'
and 3 operate the two parallel cranks 8 and 10 respectively which latter are
placed at 180° from the crank 9 and at equal distances to each side of the axis
of the cylinder 1; the cylinders 2 and 3 communicate normally with their upper
end with the lower end of the cylinder 1.
The steam, distributed by a single valve, placed at 20 or at any other convenicut
point and of similar disposition to that shown in Figure 1 admits the live steam
over the piston 1 and directs the same steam at the next stroke into the
space 1, 2, 3, comprised between the three pistons 1'21 31 and thence at the next
stroke into the condenser.
In other words, the volume corresponding to the high pressure cylinder is
given by the cylinder 1 during the down stroke of the piston 1¹ and the volume
corresponding to the low pressure cylinder is given by that of the cylinders 1, 2, 3
during the upstroke of the piston 1' and the down stroke of the pistons 21 and 3¹.
The operation of this engine is similar to that of the previously described
engine, it acts with high pressure during one stroke and as a compound
during the following stroke, and so forth.

page_text: HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.