IMPROVEMENTS IN STEAM ENGINES
Year: 1861

page_text: LETTERS PATENT to James Mash, of Manchester, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
ENGINES,"
Sealed the 16th October 1861, and dated the 29th April 1861.
PROVISIONAL SPECIFICATION left by the said James Mash at the
Office of the Commissioners of Patents, with his Petition, on the
29th April 1861.
I, JAMES MASH, of Manchester, in the County of Lancaster, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
ENGINES," to be as follows:-
My improvements relate to the construction of steam engines and the action
of steam therein, & consist in rendering available for power the impulsive
force due to the velocity of steam by causing steam to act on the ordinary or
other pistons of steam engines in jets, whereby it acts not by simple pressure
only, but also by impulsive force due to velocity of the steam impinging on the
piston.
In addition to the pistons of,.ordinary steam engines I employ (with
reference to one cylinder only), by preference, two auxiliary pistons, one of
which is at each side of the. ordinary piston between the ordinary piston and
the end or cover of the cylinder; the ordinary piston is thus between the
auxiliary pistons. The two auxiliary pistons are connected together by piston

page_text: rods, and are connected by any of the usual means of connection common in
steam engines, to the crank shaft, to which the ordinary piston is connected, or
to another crank shaft, or otherwise so arranged or connected that the strokes
of all the pistons are made in unison, and having a length of stroke in the
cylinder of less amount than that of the ordinary piston. In engines of ordi-
nary size I prefer the length of stroke of the auxiliary piston to be about or
that of the ordinary piston. The pistons make their strokes in the cylinder in
the same time, and the distance between the auxiliary pistons is sufficient to
allow a traverse of the ordinary piston between them of the length equal to
the difference of strokes between the ordinary & the auxiliary pistons. The
auxiliary pistons are perforated with holes, through which when the engines
are working the steam passes in the form of jets. Steam is admitted to the
cylinder by any usual or approved valve apparatus, and enters the cylinder
between the cylinder covers or ends and the auxiliary pistons, upon the surface of
which it acts in the usual manner of steam pressure in steam engines for
power by simple pressure, and passing through the perforations in the auxiliary
pistons issues therefrom in jets at velocities proportioned to the pressure of
the steam, and impinges with considerable impulsive force on the surfaces of
the ordinary piston. The induction & eduction of steam to the cylinder is
effected alternately at each end in the usual manner in steam engines.
Although I have above described auxiliary pistons moving within the cylinder
as preferable, the mechanical arrangements may be modified, as these may be
made stationary as additional ends or covers, or stationary plates in the
cylinders, and the ordinary pistons only having motion within the cylinders.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Mash in the Great Seal Patent Office on the 28th
October 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MASH, of Manchester, in the County of Lancaster, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of April, One thousand eight
hundred and sixty-one, in the twenty-fourth year of Her reign, did, for
Herself, Her heirs, and successors, give and grant unto me, the said James
Mash, Her special license that I, the said James Mash, my executors, admi-
nistrators, and assigns, or such others as I, the said James Mash, my
executors, administrators, and assigns, should at any time agree with, and

page_text: no others, from time to time and at all times thereafter 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 "IMPROVEMENTS IN STEAM ENGINES,"
upon the condition (amongst others) that I, the said James Mash, 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 tho
date of the said Letters Patent.
NOW KNOW YE, that I, the said James Mash, 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 and accompanying Drawings (that is to say) :-
My improvements relate to the construction of steam engines and the
action of steam therein, and consist in rendering available for power the.
impulsive force due to the velocity of steam by causing steam to act on the
ordinary or other pistons of steam engines in jets, whereby it acts not by
simple pressure only, but also by impulsive force due to the velocity of the.
steam inpinging on the pistons.
In addition to the pistons of ordinary steam engines I employ (with reference
to one cylinder only) by preference two auxiliary pistons, one of which is at
cach side of the ordinary piston between the ordinary piston and the end or
cover of the cylinder; the ordinary piston is thus between the auxiliary pistons..
The two auxiliary pistons are connected together by piston rods, and are con-.
nected by any of the usual means of connection common in steam engines to
the crank shaft, to which the ordinary piston is connected, or to another crank
shaft, or otherwise so arranged or connected that the strokes of all the pistons.
are made in unison and having a length of stroke in the cylinder of less amount.
than that of the ordinary piston. In engines of ordinary size I prefer the
length of stroke of the auxiliary pistons to be about or that of the ordinary
piston. The pistons make their strokes in the cylinder in the same time, and
the distance between the auxiliary pistons is sufficient to allow à traverse of.
the ordinary piston between them of a length equal to the difference of strokes
between the ordinary and the auxiliary pistons. The auxiliary pistons are.
perforated with holes through which, when the engines are working, the steam
passes in the form of jets. Steam is admitted to the cylinder by any usual oi
approved valve apparatus, and enters the cylinder between the cylinder covers
or ends and the auxiliary pistons, upon the surface of which it acts in the

page_text: usual manner of steam pressure in steam engines for power by simple pressure,
and passing through the perforations in the auxiliary pistons issues therefrom
in jets at velocities proportioned to the pressure of the steam, and impinges
with considerable impulsive force on the surface of the ordinary piston. The
induction and eduction of steam to the cylinder is effected alternately at each
end in the usual manner in steam engines.
Although I have above described auxiliary pistons moving within the
cylinder as preferable, the mechanical arrangements may be modified, as these
may be made stationary, as additional ends or covers or stationary plates in the
cylinders, and the ordinary pistons only having motion within the cylinders.
My improvements are applicable to all descriptions of steam engines wherein
steam acts on moveable pistons, whatever may be the arrangement or con-
struction of mechanism of the engines themselves, or the purposes for which
they may be intended or used, and it may be necessary or desirable therefore
under the different arrangements or constructions to modify and vary the
details by which my improvements are applied; I will therefore, with a view of
showing one modification accordingly of the application of my improvements,
describe and illustrate the application thereof to a steam engine for the screw
propeller of a steam ship (and which arrangement is also applicable to drive
machinery).
For this purpose generally the engines are made and work in pairs, but
for the purpose of describing the application of my improvements to this class
of engines, the present description as relating to one engine only will be
sufficient, reference being made in illustration to the Drawings hereunto
annexed, and to the letters and figures marked thereon.
These Drawings show portions only of such engines necessary to illustrate
my improvements. As regards this modification, therefore, Figure 1 represents
a longitudinal sectional elevation of the engine; the pistons are represented
as having just turned the back centre and commenced the inward stroke;
Figure 2 represents a sectional plan in the position of the pistons of Figure 1 ;
Figure 3 represents an elevation showing the pistons at half stroke; Figure 4,
an enlarged plan of one of the auxiliary or jet pistons; and Figure 5, a
tranverse section of this piston.
The piston A, which in other steam engines is the ordinary piston, is con-
nected in the usual manner by its piston rod B and connecting rod C to the
crank shaft D; E, E, are two jet pistons, one of them on each side of the
piston A; these are fixed on the piston rods F, F, and are connected by those
rods and by the connecting rods G, G, also to the crank shaft D. It will be
seen that the throws of those parts of the cranks of the crank shaft to which

page_text: the pistons A and E, E, respectively are connected are determined by the
lengths of strokes which the pistons respectively are required to have. In this
example the auxiliary or jet pistons E, E, are represented as having a length
of stroke equal to one half that of the ordinary piston A. The cylinder in
which these pistons work is of such a length that at the ends of the strokes of
the pistons there shall be proper practical clearances or intervals of space
between the piston A and the auxiliary or jet pistons E, E, and between the
auxiliary or jet pistons E, E, and the ends of the cylinder respectively. The
auxiliary or jet pistons E, E, are fixed on the rods F, F, at such a distance
asunder as, when taken with the length of stroke of those pistons, will allow
the greater length of stroke of the piston A to be effected between them, and
that consequently when one of these auxiliary or jet pistons E, E, is at the
end of the cylinder, the other or corresponding piston will be nearer to the
middle of the cylinder, or at a point in the cylinder determinate by the propor-
tions of the lengths of strokes of the pistons. The auxiliary or jet pistons E, E,
have each a number of apertures I, I, I, I, through them, and during the
working of the engine it is through these apertures that the steam issues in
the form of jets with very considerable velocity proportionate with the initial
pressure of steam used, and impinge upon the surface of the piston A. The
number of these jet apertures or the area of them in the aggregate should be
in such proportion to the area or diameter of the cylinder in which the pistons
work, and to the relative velocities and lengths of strokes of the pistons E, E,
and A, that the density and pressure of the steam in the space between the
pistons should not be allowed to accumulate to the extent of impeding the
proper action of the jets and their impingement upon the surface of the
piston A, or at least until towards the terminations of the strokes when the
pistons are approaching a state of rest. The distribution of steam to and from
the cylinder may be made in any manner usual in steam engines, and admitted:
to the cylinder by ports in the usual places and manner. On its first admission
to the cylinder it is admitted between the cylinder cover and the piston E;
here it exerts its force of simple pressure upon the piston E, the power being
transferred through the rods to the crank shaft D in the usual manner of
steam engines. Thus far the action of the steam and its effect is the same as
in ordinary steam engines, being that of simple pressure upon a piston.
Thence the steam passes through the jet apertures in the piston E, and
impinges with impulsive force against the surface of the piston A; this
impulsive force is at the commencement of the stroke at a maximum, as the
piston A is then near to the jet piston E, from the apertures of which the jets
of steam issue. The power thus exerted by impulsion upon the piston A is

page_text: transferred by the rods B and C to the crank shaft. Owing to the length of
stroke of the piston A being greater than that of the pistons E, E, the former
will gradually recede from the latter, thus gradually increasing the space
between them, and allow room for the expansion of the steam of the jets.
The pressure of steam in this space will, however, increase by accumulation
from the jets, and will necessarily act as back pressure against the jet piston E,
while on the other hand it acts as available power pressure upon the piston A,
the back pressure against which is that due to communication to the condenser
where the engine is a condensing one; or to the atmosphere where it is.a non-
condensing one. The opposite end of the cylinder to that at which the steam
is acting is as usual exhausted from the steam of the preceding stroke, and in
order that the exhaustion of that steam contained in the space between the
pistons be effected with sufficient rapidity (particularly in engines. where the
pistons are moving at high velocities), it is facilitated by the exhaust valves
H, H, one of which is in each of the jet pistons E, E; these valves open
towards the ends of the cylinders; their action is, that upon the steam strokes
they remain closed, and allow no. steam to pass through them, but on the
exhausted sides of the strokes they will be opened by the steam in the spaces
between the pistons and are closed again when the exhaustion is effected.
The power of the steam then as obtained by my improvements is as follows:-
First, that due to simple initial pressure upon the jet piston E, E; second,
the impulsive. force due to the velocity of the jets upon the piston A; and,
third, that due also to simple initial pressure on the piston A. Reference to
Figure 3 will show the relative positions of the pistons at half stroke.
"
I will now briefly refer to the remaining Figures in the Drawings, which
show the adaptation of my improvements to an ordinary beam engine, Figure 6
representing a longitudinal elevation, and Figure 7 a transverse elevation at
the cylinder end, the cylinder in both Figures being shown in section; as the
pistons and their actions are the same as I have already fully specified, will not
require description further than to state that the proportions of the length of
strokes of the pistons respectively are here shown to be as 3 to 5. The con-
nection between the jet pistons E, E, and the crank shaft D is made by the
links L, L, the beams M, M, and connecting rods N, N; the beams M, M,
vibrate loosely.on the main gudgeon of the ordinary beam of the engine, and
are placed one of them on each side of it.
Although I have herein shewn and described my improvements as carried into
operation by arranging and constructing the jet apertures in moveable pistons,
and which most usually in practice I prefer, I sometimes find it advantageous
or desirable to form and construct the jet apertures in plates fixed at the ends

page_text: of the cylinders, as, for example, in engines in which the strokes of the pistons
are very short.
Iaving now described my improvements and their application, I claim as
my Invention for the purpose of obtaining power from the velocity or impulsive
force of steam,-
First, the application to and employment in steam engines of jets of
steam impinging or acting with velocity or impulsive force against moveable
pistons.
Second, the application to and employment in steam engines of moveable
pistons against which jets of steam impinge with velocity or impulsive
force.
Third, the application to and employment in steam engines of moveable
pistons through which or from which jets of steam issue with velocity or
impulsive force.
Fourth, the application to and employment in steam engines of two or more
moveable pistons in each cylinder, having different rates of velocity, in
conjunction with jets of steam acting with velocity or impulsive force.
Fifth, the application to and employment in steam engines of fixed or
stationary plates, through which or from which jets of steam issue with
velocity or impulsive force.
In witness whereof, I, the said James Mash, have hereunto set my
hand and seal, this Twenty-fourth day of October, in the year of our
Lord One thousand eight hundred and sixty-one.
JAMES MASH. (L.S.)