IMPROVEMENTS IN STEAM ENGINES
Year: 1876

page_text: LETTERS PATENT to Edmund Edwards, of the Firm of Edwards and Co., 40,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Engineers
and Patent Agents, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
A communication from abroad by James Moorhouse; of St. Petersburgh in the
Empire of Russia
Sealed the 7th October 1876, and dated the 10th May 1876.
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at the
Office of the Commissioners of Patents on the 16th May 1876.
EDMUND EDWARDS, of the Firm of Edwards and Co., 40, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Engineers and Patent Agents. "IM-
PROVEMENTS IN STEAM ENGINES."
This Invention relates to that description of steam engine known as a rotary
engine, in which a driving shaft is mado to revolve by means of the direct action
of steam upon one or more pistons or their equivalents attached to it without the
intervention of piston rods, connecting rods, or cranks. It has for its objects im-
proved methods of arranging and constructing such engines so that they are simpler'
and more effective than when arranged and constructed in any of the methods
ordinarily used and practised.
A cylinder of any desired internal diameter and fitted with ends is arranged
(preferably with its axis horizontal) upon a suitable bed plate or foundation, and
has the driving shaft which is to be actuated passing through it (preferably through
stuffing boxes in the ends) and revolving in suitable bearings. The cylinder is built
up or composed of a series of separate compartments, the number of which it is
preferred to make proportionate to the pressure of the steam used, and in ench of
these compartments revolves a piston or its equivalent having its edge or circum-
ference made steam tight or nearly so in the usual way. The steam being admitted
though a suitable opening or pipe at one end of the cylinder into the first compart-
ment of the latter, operates upon the piston contained in it, which together with the
driving shaft to which it is attached is thus caused to make a revolution, and the
[Price 87.1

page_text: 3
steam then passes into the second compartment and operates in turn upon the second
piston (of different area) in the same way, and thence to the third compartment
and so on though as many compartments as the cylinder is divided into, being
discharged finally through the opposite end of the cylinder into the open air or
into a condenser connected to an air pump worked by the engine in the usual
way.
The apparatus constructed as described works at a great speed, is simple and cheap
in construction, and occupies very little space, and contains no valves excepting a
regulating valve or throttle valve of the usual construction.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Edmund Edwards in the Great Seal Patent Office on the 15th November
1876.
EDMUND EDWARDS, of the Firm of Edwards and Co., 40, Southampton Buildings,
Chancery Lano, in the County of Middlesex, Engineers and Patent Agents. "IM-
PROVEMENTS IN STEAM ENGINES." A communication from abroad by James Moor-
house, of St. Petersburgh, in the Empire of Russia.
33
This Invention relates to that description of steam engine known as a "rotary
engino, in which a driving shaft is made to revolve by means of the direct action
of steam upon pistons or their equivalents attached to it without the intervention
of piston rods, connecting rods, or cranks. It has for its objects improved methods
of arranging and constructing such engines so that they are simpler and more
effective than when arranged and constructed in any of the methods ordinarily
hitherto used and practised.
This improved engine consists of a cylinder of iron or other suitable material,
built up in sections, held together by longitudinal bolts, each section composing a
separate compartment, the number of compartments varying according to the
pressure of the steam to be used and the amount of expansion required. This
cylinder thus built up is fixed upon a suitable foundation in a horizontal or any
other desired position, and through the centre of it passes a revolving driving shaft
of iron, steel, or other suitable material, which passes through stuffing boxes formed
in the ends of the cylinder. Or sometimes the driving shaft is made to pass
through one end only of the cylinder, the inner extremity of the shaft revolving in
a bearing fitted to or formed upon the inside of the corresponding end of the cylinder.
Upon the driving shaft toothed wheels, driving pulleys, or friction pulleys may
bo fixed for the purpose of driving any machinery as desired. Upon the shaft
inside the cylinder, built up as described, are fitted and fixed a series of wheels,
each having at or near its circumference a sufficient number of vanes, chambers,
or buckets, resembling those ordinarily used in turbines driven in the usual way
by water. These turbine wheels are as many in number as the compartments
into which the cylinder is formed as already described, and each compartment
with its contained turbine wheel is separated from the adjoining compartments by
means of a dividing plate or diaphragm of metal or other suitable material, formed
upon or attached to each separate section of the cylinder, or fitted upon the driving
shaft and held between each such section when the engine is put together, the
position of the dividing plates being such that each succeeding compartment is of
greater capacity than the one preceding it. The steam or other elastic driving
fluid is admitted at or near one end of the cylinder, and is discharged at or
near the other end either into the open air, or if steam is used, into a condenser
connected to an air pump operated by the engine itself, or by other means in the
way well understood and practised. In its passage it passes through each com-
partment of the cylinder in succession, and actuates the turbine wheel contained

page_text: in each such compartment, in the manner herein-after described, and thus causos
the revolution of the driving shaft to which the turbine wheels are attached.
Openings are made in the division which separates each compartment from the
next compartment, and the area of these openings is proportioned to the pressure
of the steam or other driving fluid which is to be used, and to the number of
compartments and of turbine wheels, and to the extent to which it is desired that
the steam should be expanded when it is finally discharged from the engine. In
this way the steam admitted at a high pressure into the first compartment passes
through the openings into the second compartment, the openings being of such area
and the compartments of such relative capacity that the steam expands to a calcu-
lated extent in its passage. The same process is repeated in its passage through
the openings from the second to the third compartment, and so on through as many
compartments as the cylinder is divided into, until from the last compartment
it passes out as already described. In its passage between each compartment the
steam operates upon and passes through the vancs or chambers of the turbine
wheel, which is thus driven with a force proportioned to the difference in pressure
of tho steam in that particular compartiment and the next larger one. By this
arrangement the difference in pressure between each two adjoining compart-
ments is but of comparatively small amount, and it is thus possible to actuate
the turbine wheels and the driving shaft at a moderate and practicable speed,
which is impossible where high pressure steam is used to operate a single turbine
wheel.
In illustration of the method in which the Invention is put in operation
supposing that steam at a pressure of 96 lbs. per square inch is to be used, it is
admitted into the first compartiment of the cylinder at that pressure; the openings
into the second compartment are made of such area and the relative capacity of
that compartment such that the steam is in it increased in volume, but reduced
to a pressure of 92 lbs. per square inch, and the turbine wheel which is actuated
as the steam passes from the first to the second is operated upon by an effective
pressure and at a speed due to a pressure of 4 lbs. per square inch only. In
the same way, the steam in passing from the second to the third compartment of
the cylinder is again reduced in pressure 4 lbs. per square inch but increased in
volume proportionately, the area of the openings and the capacity of the third
compartment being increased to a corresponding extent. It then passes aga'n
through a series of twenty-four compartments, actuating a turbine wheel in ca h
succeeding one, and increasing in volume but decreasing in pressure as it passes
through openings of gradually increasing area into chambers each of gradually
increasing capacity. In the twenty-fourth compartment there will therefore be
a pressure of four lbs. per square inch only, and the steam may then be discharged
at that pressure into the air, or it may pass into another compartment (operating a
turbine wheel) through openings of area sufficient to retain a pressure of two lbs.
per square inch, and from the last compartment, after operating a turbine wheel,
it is allowed to escape into the air or to a condenser. In the last divisions where
the effective pressure is, as described, only 2 lbs. per square inch, and the velocity
of the turbine wheel should accordingly bo less in the proper proportion, the
turbine wheels are made of le diameter, so that while they make the same
number of revolutions per minute, their circumference travels at a speed less
in the proportion desired. In the compartments of the cylinder through which the
steam first passes the proportionate increase in their capacity is so small that in
practice they may be made of equal size.
The accompanying Drawings are in illustration of this Invention.
Figure 1, Sheet I., is a side view of an engine constructed according to this
Invention. Figure 2, Sheet II. is a sectional plan, Figure 3, Sheet III, a transverso
section, and Figure 4, Sheet IV., an end view of the same.
a is the cylinder built up in sections b, b, b, b³, b, &c., provided with ends d, d',
firmly held together by the longitudinal bolts c, e, c, c. The central driving shaft f

page_text: is shewn passing through stuffing boxes g, gl, in the ends of the cylinder, and has
keyed upon it the turbine wheels i, i, i, i, i, i, i, i, i, &c., each of which fits into
and revolves in one of the compartiments into which the cylinder is divided. These
compartments gradually increase in capacity (in the proportion already described)
from end to end of the cylinder a, the smallest being at the end where the steam
is admitted through the inlet pipe, and the largest being at the other end, where
it is discharged through the oxhaust into the open air or into a condenser. The
turbine wheels are shewn firmly and steadily held together upon the shaft by the
spring and the nuts . Openings (of a properly proportioned area as already
described) are made between each compartment at n,,,,, n³, nº, n², n", &c.,
through which the steam passes, as shewn by the arrows, and in its passage
actuates and passes through the buckets or chambers at the circumference of the
turbine wheels i, i, i, i, i, i, &c., causing the latter to revolve at a speed dependent
upon the velocity of the steam, this velocity being itself dependent upon the
effective pressure of the steam or the difference in its pressure between the two
adjoining compartments, as already explained. After operating the turbine
wheels i, i, in the last two compartiments, which are made of less diameter for
the reason already explained, the steam escapes through the exhaust passage
The steam is shewn actuating the last turbine wheels from the outside instead of
the inside. The holes or openings in the partitions may be cast in the latter, or
they may be bored subsequently. The driving shaft has keys fitted into it where
the bosses of the turbine wheels fit upon it, and the latter have corresponding key-
ways cut in them, so that they can be slipped upon the shaft one after another
and kept firmly in their position by the spring and nuts upon the shaft, as already
described and shewn. The turbine wheels may be made either of sheet steel, iron,
copper, or other suitable material, upon which the vanes or chambers at the
circumference are formed or fixed, or they may be made of cast-iron, brass, or
other suitable metal. It is not necessary that the turbine wheels should be made
to travel at the same speed as the steam which actuates them, as assumed in the
foregoing description. They may be made to travel at a less speed than that of
the steam, and very good results may be obtained when the velocity of the wheels
is half that of the steam.
Instead of the arrangement described above and shewn in the Drawings some-
times the separate compartments of the cylinder are constructed so that the steam
passes from one to the other of them through passages or openings, each of which
can be regulated by a cock or valve. In this way the regulation of the proper
pressure in each compartment can be accurately effected.
Various forms of turbine wheels may be used, and sometimes instead of making
the steam pass from the outside to the inside of each wheel in succession through
the series, as shewn in the Drawings, it is made to pass from the outside of one to
the inside of the next, and from the inside of the latter to the outside of the
succeeding one, and so on.
I do not confine myself to the precise form and details of the arrangement of the
apparatus as described and shewn in the Drawings, which may be varied to suit
varying circumstances, but I claim―
The general construction and arrangement of apparatus substantially as de-
scribed.
Also the arrangement of a number of turbine wheels upon the same driving
shaft, each working in a separate compartiment and driven by the pressure of an
elastic fluid, substantially as and for the purpose described and shewn in the
Drawings.
Also the method of varying the pressure of steam or other elastic fluid in each
compartment by varying the number or size of the openings or other communication
in the partitions between the compartments, substantially as and for the purpose
described and shewn in the Drawings.
Also the method of forming the separate compartments for the turbine wheels

page_text: by building a cylinder in separate sections, substantially as described and shewn in
the Drawings.
In witness whereof, I, the said Edmund Edwards, have hereunto set my hand
and seal, this Fourteenth day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
EDMUND EDWARDS. (LS.)