Improvements in Steam Engines.
Year: 1892

page_text: Date of Application, 29th Sept., 1892
Complete Specification Left, 29th June, 1893-Accepted, 23rd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Steam Engines.
JAMES MUSGRAVE of the Firm of John Musgrave & Sons Ltd. Engineers
Bolton Lancashire GEORGE DIXON Manager to John Musgrave & Sons Ltd.
Engineers Bolton Lancashire, EDWARD FIELD and FRANCIS SANDERS MORRIS,
both of 22 Buckingham Street Adelphi in the County of London Engineers, do
hereby declare the nature of this invention to be as follows:-
The object of our invention is to reduce the consumption of steam in steam
engines, by means of heated air, or gas. We introduce heated air, or gas, into the
cylinder, during the period of exhaust, causing it to take the place of the mixture
which has already done work, so that when the piston is nearing the end of its
stroke, & the exhaust port closes, the hot air is compressed into the clearance spaces,
so that on the admission of the steam at the end of the stroke, all the surfaces with
which it comes into contact, will have been raised to such a temperature, that
initial condensation will be much reduced, or even entirely prevented.
presence of the heated air, or gas, will also have an important influence, as experi-
ments have shown that when steam is mixed with air, or gas, sufficiently heated,
great expansion takes place, so that considerable economy may be expected from
this source.
The
For the proper admission, & control, of the supply of heated air, or gas, we
provide suitable valves, placed in the sides, or covers, of the cylinder. The heated
air, or gas, may also be introduced into the cylinder by means of valves, placed in a
hollow piston, into which it is conveyed, by means of a hollow piston rod, which
passing through the end, or covers of the cylinder, terminates in an air reservoir.
Stuffing boxes of the usual form would be provided, for the rod to pass through.
The hollow rod may be made to drive an air pump, the air pnmp bucket being
secured to its outer end. The bucket would be provided with suitable valves for
admitting the air, or gas, to the hollow rod.
The air pump, or blower, may also be driven in any other suitable way, for com-
pressing the air, either before, or after, it is heated.
Where a sufficiently high pressure of steam is available, two, or more, cylinders
may be employed. The steam would be expanded in the first cylinders in the usual
way, the hot air or gas being introduced into the low pressure cylinder, as
described above.
In conjunction with any of the methods of using heated air or gas described
above, the heated air, or gas, may be employed to superheat the steam, after it
leaves the boiler, by causing it to pass through vessels, or pipes, surrounded by the
heated air, or gas. The cylinders, covers, valve chests, or receivers, may also be
surrounded by hot air, or gas, to prevent radiation.
We purpose heating the air, by means of the waste gases on their way to the
chimney, or by any other suitable means. The waste gases themselves, may also
be employed, after being purified of all grit, or other matter, likely to injure the
working parts of the engine.
Dated this 28th day of September 1892.
JAMES MUSGRAVE,
GEORGE DIXON.

page_text: COMPLETE SPECIFICATION.
Improvements in Steam Engines.
We, JAMES MUSGRAVE of the Firm of John Musgrave and Sons Ltd.
Engineers, Bolton, in the County of Lancaster, GEORGE DIXON, Manager to
John Musgrave and Sons Ltd., Engineer, Bolton, Lancashire, EDWARD FIELD
and FRANCIS SANDERS MORRIS both of 22 Buckingham Street, Adelphi, in the
County of London, Engineers, 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 :-
The object of this invention is to reduce the consumption of steam in steam
engines by the use as hereinafter described of heated air or gas. We introduce
heated air or gas into the cylinder, during the period of exhaust, causing it to take
the place of the mixture which has already done work, so that when the piston is
nearing the end of its stroke and the exhaust port closes, the hot air or gas is com-
pressed into the clearance spaces, and on the completion of the stroke, when steam
is admitted for the return stroke, the surfaces with which it comes into contact
have been by the use of the hot air or gas raised to such a temperature that initial
condensation is much reduced or even practically prevented. The presence of the
heated air or gas will also have an important influence as experiments have shewn
that when steam is mixed with air or gas sufficiently heated great expansion takes
place so that considerable economy may be expected from this source.
For the proper admission and control of the supply of heated air or gas we
provide suitable valves, placed in the sides or covers of the cylinders. The heated
air or gas may also be introduced into the cylinder by means of valves placed in a
hollow piston, into which it is conveyed by means of a hollow piston rod, which,
passing through the end or cover of the cylinder, terminates in an air reservoir.
We provide stuffing boxes of, ordinary or suitable kind for the rod to pass
through.
The hollow rod may be made to drive an air pump, the air pump bucket or piston
being secured to its outer end. The bucket or piston is provided with suitable
valves for admitting the air or gas to the hollow rod. The air pump or blower
may also be driven in any other suitable way for compressing the air, either before
or after it is heated.
Where a sufficiently high pressure of steam is available two or more cylinders
may be employed the steam being expanded in one or more cylinders in the usual
way and exhausted therefrom and hot air or gas being introduced as hereinbefore
described into the final or low pressure cylinder.
In conjunction with any of the methods of using heated air or gas described
above, the heated air or gas may be employed to superheat the steam after it leaves
the boiler, by causing the steam to pass through vessels or pipes surrounded by the
heated air or gas.
The cylinders, covers, and valve chests or receivers may be jacketted and
surrounded by hot air or gas circulating in the jackets to prevent radiation and
maintain a suitable temperature. We may heat the air by means of the waste
gases on their way to the chimney or by any other suitable means.
The waste gases themselves may be employed in the engine cylinder in lieu of
heated air after being purified of all grit or other matter likely to injure the
working parts of the engine.
Such purification of the gases might be effected by means of apparatus such as
shewn in and described with reference to Fig. 7 of the drawings appended to the
Specification of Letters Patent No. 1997 of the year 1889, granted to
Edward Field.
Referring to the accompanying drawings,
Figs. 1 and 2, represent the cylinder of a steam engine with valves for the
admission of heated air or gas (for example hot waste gas purified as already

page_text: referred to) arranged in the sides of the cylinder; Fig. 1 being a side elevation
and Fig. 2 an end elevation both partly in section.
a is the cylinder, h, are its covers, c is the hot air or gas valve chest, d is the
inlet for the heated air or gas; e e are the valves for controlling the admission of
heated air or gas to the cylinder, ff are their seats; 9, 9, ports for conducting
the heated air or gas into the cylinder; these ports are (as shown) so shaped as to
deliver the heated air or gas into the cylinder in a longitudinal direction such as is
favorable for ejecting, through the exhaust port h, the mixture which has just
previously done work in the cylinder. The valves e are held closed by the springs i,
until, owing to the opening of the exhaust valves, the pressure of fluid in the
cylinder is sufficiently reduced to allow the pressure of heated air or gas to open
the valves e. The heated air or gas then flows into the cylinder, ejecting (through
the exhaust port h) the mixture which has just before done work; and, on the
closing of the exhaust valve, a portion of the heated air or gas is compressed into
the clearance spaces, as the piston K completes its stroke.
For convenience of inspection and repair the valve chest c may be made
separate from the cylinder, as shown. The heated air or gas enters by the
branch d.
Figs. 3 to 7, illustrate a modification in which the hot air or gas valves are
arranged in the covers of the cylinders;
Fig. 3 being a sectional elevation shewing the cylinder and its covers;
Fig. 4 an end view of the cover, as seen from the inside;
Fig. 5 a corresponding view as seen from the outside ;
Fig. 6 a sectional view, to a larger scale, of the hot air or gas inlet and valve for
same; and
Fig. 7 a device for protecting the working parts from injury in case a valve
should become detached from its spindle.
dd are inlet branches for the heated air or gas, e e are the valves and ff their
seats; the construction and arrangement of these is shown in detail in Fig. 6.
The ports and passages for the admission of steam, and for the exhaust from the
cylinder, are shown as of the ordinary Corliss type; but any well known or suitable
forms of valves and ports may be adopted. A cross piece, such as e¹ (Figs. 6 and 7)
is securely attached to the cover, in front of each hot air or gas valve, to prevent
the possibility of a valve getting inside the cylinder.
With regard to the temperature and pressure of the air; we have found when
working such an engine with steam at a pressure of from 100 lbs. to 120 lbs. per
square inch that a temperature of about 400 degrees Fahr. is suitable for the air.
Its pressure should be sufficient to overcome the back pressure of the exhaust; we
have obtained satisfactory results when using air at a pressure of about half a
pound per square inch in excess of the back pressure of the exhaust.
Figs. 8 and 9, show an arrangement of hollow piston K with valves and hollow
rod, for admitting the heated air or gas into the cylinder. The valves e, e, for
the admission of the heated air or gas are of similar type to those already
described; they are connected together, in pairs, by springs, the spring o which
For
connects two valves acting to keep both valves normally against their seats.
each pair of valves there is provided a removable casing m in which the valve
seats are formed and which is made with slots or openings for the passage of
hot air or gas.
When all the casings are in place they are secured by the junk
ring n.
Fig. 10 shows an arrangement for introducing heated air or gas to the hollow
piston. In this case the hollow rod carries at its outer end a head p having
ports y so arranged as to secure an equal admission of air to the interior of the rod
whichever way it is travelling. The reservoir r in which the rod works com-
mmunicates with the heater by means of pipes attached to the branch s.
Fig. 11 shows a modification in which the hollow rod / slides telescopically in
the pipe t, which is in communication with the heater.
Fig. 12 shows an arrangement wherein the hollow piston rod & drives an air

page_text: pump.
In this case the bucket or piston u of the pump is provided with the air
valves for admitting heated air or gas to the hollow rod 1, the valves v being
kept normally against their seats by springs wo, acting in compression.
The branch communicates with the heater; y y are the admission valves to the
pump.
.l'
The valves shown in the drawings for the admission of the heated air or gas to
the engine cylinder are intended to be opened by a slight fluid pressure generally
say about lb. to one pound per square inch in excess of the back pressure of
the exhaust which slight pressure can be maintained by a fan, blower, or air pump
that may be placed in any suitable position for causing a current of heated air or
gas to flow into the cylinder; or the inflow of heated air or gas to the cylinder
may be caused by creating a partial vacuum in the cylinder by means of a suitable
exhauster.
Fig. 13 shows in plan a general arrangement of the system applied to a stationary
engine.
1 is the boiler, 2 the engine, 3 the fan or blower, which may be of the well
known "Root" type; 4 is the air heater, constructed, in this example, with metal
pipes through which the air passes, the hot gas circulating around the outsides of
The heater is
these pipes; but this arrangement might obviously be reversed.
shown placed in the boiler flue; 5 is a super-heater, through which the steam and
air pass one within and the other around metal pipes. The pipes 6, 7, 8, constitute
the air supply; they respectively connect the blower to the heater; the heater to
the superheater; and the superheater to the engine cylinder; the pipes 9, 10
conduct the steam, respectively, from the boiler to the superheater and from the
superheater to the engine.
The air heater may be placed in any suitable position; it may either take the
heat directly from the furnace of the boiler; or it may take only the waste heat on
its way to the chimney; or the heater may be divided, part being heated by waste
heat, and part by direct heat; or a special furnace may be provided. In iron,
steel, or other works, the waste heat from the various furnaces in use may be
utilized to heat the air.
As will be evident, this invention may be carried out in various forms and applied
in engines designed for various purposes whether stationary marine or locomotive
simple or compound and whether the steam be expanded once or twice or other
number of times successively. Again instead of introducing the hot air or gas into
the cylinder entirely through valves in the sides or ends of the cylinder or through a
hollow piston, it might be introduced into the cylinder partly through valves in the
cylinder sides or ends (or both) and partly through a hollow piston. In lieu of air
valves of the forms shown in the drawings valves of any other suitable construction
might be employed, such for examples as slide valves, Corliss valves, or piston valves
these being actuated as well understood by any suitable means such as eccentrics,
levers, cams, or slip motions for admitting or cutting off the supply of hot air or gas
to the cylinder at any required point of the stroke taking care to provide against
the opening of the valves for admitting hot air or gas to the cylinder until after
the pressure in the cylinder has been reduced below the available pressure of hot
air or gas and also to provide for the closing of the air or gas admission valves
before the proper time for cominencement of the compression of the hot air or gas
in the cylinder. Engines according to this invention may be constructed with two
or more cylinders in each or some of which steam direct from the boiler may be
used in conjunction with heated air or gas introduced into the cylinder as and for
the purpose above set forth.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. Causing heated air or gas to be introduced into a steam engine cylinder during
the period of exhaust at the same side of the piston as and in such a manner as to

page_text: take the place of the escaping motive fluid that has just previously done work in
the cylinder, such heated air or gas being, when the piston is nearing the end of
its stroke and the exhaust port closes, compressed into the clearance space,
preparatory to the admission of steam for effecting the return stroke, as set
forth.
2. A compound steam engine wherein steam is expanded in the usual way in one
or more cylinders and is afterwards expanded into a lower pressure cylinder into
which heated air or gas is introduced during the exhaustion of the motive fluid
from such lower pressure cylinder the heated air or gas so introduced being
compressed within the clearance space as hereinabove described.
3. In an engine of the kind referred to in Claim 1, admitting heated air or gas
in the manner set forth to the cylinder for the purpose specified through ports
controlled by valves arranged at the side of the cylinder and supplemental to the
steam admission ports as described with reference to Figs. 1 and 2 of the drawings.
4. In an engine of the kind referred to in Claim 1, admitting heated air or gas
to the cylinder for the purposes specified through ports controlled by valves
arranged in the cylinder covers and supplemental to the steam admission ports as
described with reference to Figs. 3 to 7 of the drawings.
5. In an engine of the kind referred to in Claim 1 admitting heated air or gas
through a hollow piston to the cylinder for the purpose specified.
6. In an engine of the kind referred to in Claim 1 admitting heated air or gas
to the cylinder for the purpose specified, through a hollow piston and rod from a
reservoir into which the hollow rod enters as described with reference to Fig. 10
of the drawings.
7. In an engine of the kind referred to supplying heated air or gas to the engine
cylinder by means of a pump the piston of which is made hollow, is connected to
the hollow piston rod and piston of the engine, and is provided with valves for
admitting heated air or gas to the said hollow piston rod during the working of the
pump, as described with reference to Fig. 12 of the drawings.
Dated this 29th day of June 1893.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.