Improvements in or pertaining to Compressed Air Motors and in Heating Stoves therefor.
Year: 1890

page_text: Date of Application, 29th May, 1890
Complete Specification Left, 21st Feb., 1891-Accepted, 11th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in or pertaining to Compressed Air Motors and in
Heating Stoves therefor.
I, VICTOR POPP, of 54, Rue Etienne Marcol, Paris, France, Engineer, do
hereby declare the nature of this invention to be as follows:-
To enable compressed air motors to be worked with air at a high pressure,
and the compressed air to have imparted to it as large as possible an amount of
energy in the form of heat, it is advantageous to allow expansion to take place
in two or more cylinders in succession.
It is then possible to supply the air before its admission to each cylinder
with a comparatively large amount of heat without liability of injuring the
engine by high temperatures, which would be the case if the whole amount of
heat were imparted at one time to the compressed air before its admission to
the engine, apart from the fact that the great fall in temperature would itself
result in direct losses of heat.
It will be understood that in order to at all times obtain the most favourable
results from a motor with more than one cylinder, at different loads, it is
necessary to be able to regulate, according to requirement, the amounts of heat
to be supplied to the compressed air before its admission to the several cylinders,
both as respects their relative proportions, and also with regard to the total
amount of the same.
According to this invention the object in view is effected either wholly or
partially by means of heating stoves by varying the relative areas of the heating
surfaces of the respective heating bodies, or by varying the relative quantities
of the heating gases which are intended for the several heating bodies, or by
simultaneously varying both the relative heating surfaces and the relative
quantities of heating gases.
It is immaterial whether the motor employed is a compound engine with
cranks arranged at an angle to each other, or a "Woolf" engine, or is a single
acting or double acting engine.
Referring to the annexed drawings:
Fig. illustrates diagrammatically a two cylinder motor in which the com-
pressed air is separately heated before its admission to the respective cylinders.
Figs. 2 and 3 shew respectively in side elevation and vertical section, and in
plan and horizontal section a combined stove, according to this invention.
Fig. 4 shews a modified construction of stove.
Either two separate stoves A may be used, or the heating may be effected
in a single combined stove B.
In practice the latter method is preferable both on account of the greater
facility with which the stove can be worked and of the smaller space it occupies,
and also because it enables proportions and conditions that have been recognised
as being correct to be easily conformed to.
In Fig. 1 the broken lines illustrate the employment of two separate stoves,
whilst the employment of a combined stove is shewn by full lines.
The course taken by the compressed air is indicated in both cases by arrows:-
C is the high pressure cylinder, D the low pressure cylinder, and É the exhaust
pot of the motor.
The combined stove shewn in Figs. 2 and 3 consists of an ordinary vertical
stove having an outer casing f that encloses sets of tubes H, H which are
traversed by the compressed air.

page_text: The heating gases, after escaping from the shaft of the stove, are caused by
a partition to pass downwards, flowing round the inner set of tubes H; and
then to pass upwards, flowing round the outer set of tubes H¹, escaping finally
through the outlet pipe The charging, opening, in the upper closing ring or
cover P is closed by means of a lid i.
The compressed air passes in the two concentric sets of tubes in a zig zag
manner; entering for example through the opening K, Fig. 3, it passes first up
through the tube of the outer set of tubes H, through a cap M into the
tube and then down through, the latter into the annular lower box or chest N,
which, by cast partitions is divided in such a manner that each row of tubes,
(inner and outer) will comprise a number of sets of two tubes that communicate
with each other by means of the box or chest N.
Thus the compressed air then rises up through the tube 3 and passes down
through the tube and so on.
The air takes its course in the same manner in the inner set of tubes H.
Both sets of tubes can be brought into communication with one another by means
of a simple shifting or reversal of a cap, (it may be M' for instance, Figs. 2
and 3) which covers two tubes of the outer set of tubes and two tubes of the
inner set of tubes, and is provided with a. dividing bridge piece the arrange-
ment being such that the air can be compelled to How through one set of
tubes on its forward course, and to flow through the other set of tubes on its
return.
Thus for instance if the air intended for the high pressure cylinder is admitted
through opening K to the outer set of tubes H, the air will flow through the said
outer set up to the cap M, Fig. 3, and there enter the inner set of tubes H, in order,
after having heated the same to escape through the opening K2, Fig. 3.
But the air coming from the high pressure cylinder C, Fig.. 1, passes at the same
time through the opening K³ into the other part of the inner set of tubes H, travels
similarly (on the other side of the stove) up to the cap M4, and thence back through
the outer set of tubes H to. the mouth K, in order to be led into the low pressure
cylinder D.
Now according as one or the other of the several caps M, M' &c. is shifted or
reversed there is varied the proportion of the tubes through which passes the air led
into the high pressure cylinder or it may be the low pressure cylinder, and conse-
quently also the relative proportions of the heating surfaces.
In Fig. 3, for example, air is first passed through fourteen tubes and then through
eighteen tubes, but if the cap M³ be shifted, instead of cap M, the air led to the
high pressure cylinder will pass only through ten tubes to the high pressure
cylinder, and the air led to the low pressure cylinder will pass through twenty-two
tubes.
The amount of heat employed can be regulated by corresponding regulation, of
the combustion in the stove.
The several tubes 72, which are fitted in the lower chest .N in an air-tight
manner, are kept in position at the top by a ring P which serves at the same time
as an upper cover to the stove; it is supported by stay bolts p that pass through
the lower chest N. As shewn each set of four tubes (two inner and two outer) are
connected by one of the caps M which can be drawn tightly upon the tubes ', h², by
means of the bolts p.
A's hereinbefore mentioned two outer tubes and two inner tubes can be connected
together according to the position of the respective cap, or an outer tube can be
connected with an inner tube.
Fig. 4 shows a heating stove with fire place Q in which the proportion of the
amounts of the heating gases is variable. The heating gases escape through a
passage, which is divided by a pivoted tongue R, into the heating bodies
proper S, S', through heating coils T T in which the compressed air passes.
To each cylinder of the motor corresponds a heating body. The proportion of

page_text: the amount of the gases of combustion passing through the heating bodies, is
regulated by adjustment of the tongue R.
This adjustment can of course also be effected in an automatic manner by means
of the governor of the engine.
It will be readily understood without further description that in this arrangement
it is possible also to vary the amount of the heating surfaces, by providing each two
tubes with a cap U capable of being shifted as in the arrangement illustrated in
Fig. 3.
Fig. 4 (right hand) shows one of the caps in position.
In place of the vertical stove indicated in the figs. any. other source of com-
bustion or heat may be employed such as gas firing, stoves for liquid fuel,
steam &c.
The arrangement of the stoves for motors with more than two cylinders will be
readily understood from the preceding.
SML 1900
COMPLETE SPECIFICATION.
Improvements in or pertaining to Compressed Air Motors and in
Heating Stoves therefor.
I, Victor Pōrr, of 54, Rue Etienne Marcol, Paris, France, 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 :-
To enable compressed air motors to be worked with air at a high pressure, and
the compressed air to have imparted to it as large an amount of energy as possible
in the form of heat, it is advantageous to allow expansion to take place in two or
more cylinders in succession. It is then possible to supply the air before its
admission to each cylinder with a comparatively large amount of heat without
liability of injuring the engine by too high a temperature, which would be the case
if the whole amount of heat were imparted at one time to the compressed air before
its admission to the engine, apart from the fact that the great fall in temperature
would itself result in direct loss of heat, should the whole amount thereof be
imparted to the air at one time.
It will be understood that in order to at all times obtain the most favourable
results from a motor having more than one cylinder, and working with different
loads, it is necessary to be able to regulate according to requirements, the quantities
of heat to be supplied to the compressed air before its admission to the several
cylinders, both as respects their relative proportions and also with regard to the
total amount of the same.
According to this invention the object in view is effected either wholly or
partially by means of heating stoves, by varying the relative areas of the heating
surfaces of the respective heating bodies, or by varying the relative quantities of
the heating gases used for heating the said surfaces or bodies, or by simultaneously
varying both the relative areas of the heating surfaces and the relative quantities
of heating gases used.
It is immaterial whether the motor employed is a compound engine with cranks
arranged at an angle to each other, or is a "Woolf" engine, or is a single acting
or double acting engine.
Referring to the drawings filed with my Provisional Specification
Fig. 1 illustrates diagrammatically an arrangement of two cylinder motor with
heating stove or stoves in which the compressed air is separately heated before its
admission to the respective cylinders.

page_text: Fig. 2 shows partly in side elevation and partly in vertical section; and
Fig. 3 partly in plan and partly in horizontal section, a combined stove, according
to this invention.
Fig. 4 shows a modified construction of stove.
Either two separate stoves A may be used, or the heating may be effected in a
single combined stove B. In practice the latter method is preferable both on
account of the greater facility with which the stove can be worked and of the
smaller space it occupies, and also because it enables proportions and conditions
that have been recognised as being correct to be easily conformed to.
In Fig. 1, the broken lines illustrate the employment of two separate stoves,
whilst the employment of a combined stove is shown by full lines. The course
C is the high
taken by the compressed air is indicated in both cases by arrows.
pressure cylinder: D the low pressure cylinder; and E the exhaust pot of the
motor.
The combined stove shewn in Figs. 2 and 3 consists of an ordinary vertical
stove F having an outer casing that encloses sets of tubes H, H' which are
traversed by the compressed air.
The heating gases after escaping from the shaft of the stove, are caused by a
partition g to pass downwards, Howing around the inner set of tubes H, and then to
pass upwards, flowing around the outer set of tubes H', escaping finally through
the outlet pipe f. The charging opening in the upper closing ring or cover l', is
closed by means of a lid i.
The compressed air passes through the two concentric sets of tubes in a zig-zag
manner entering for example through the opening K, (Fig. 3) it passes first up
through the tube of the outer set of tubes H, through a cap M' into the tube h²
and then down through the latter into the annular lower box or chest N, which, by
cast partitions is divided in such a manner that each row of tubes (inner and outer)
will comprise a number of sets of two tubes that communicate with each other by
means of the box or chest N. Thus the compressed air, after descending the
tube 2 and box or chest N rises up through the tube ³, and passes down through
the tube and so on.
Both
The air circulates in the same manner through the inner set of tubes H.
sets of tubes can be brought into communication with one another by a simple
shifting or reversal of one of the caps, (it may be M' for instance, Figs. 2 and 3)
through an angle of 90°. These caps each cover two tubes of the outer set of
tubes and two tubes of the inner set of tubes as shown, and is provided with a
dividing bridge piece; the arrangement being such that the air can be compelled
to flow either through one set of tubes on its forward course, and to flow through
the other set of tubes on its return course as shown by the caps M2 M³, or by
turning the cap through 90° (as shown at M4) the air can be caused to pass directly
from one set of tubes to the other. Thus for instance if the air intended for the
high pressure cylinder is admitted to the outer set of heated tubes H, the air will
flow through the said outer set up to the cap M', (Fig. 3) and there enter the inner
set of heated tubes H, in order, after having become heated therein, to escape through
the opening K, Fig. 3. But the air coming from the high pressure cylinder C,
Fig. 1, passes at the same time through the opening, into the other portion of
the inner set of heated tubes H, travels similarly (on the other side of the stove) up
to the cap M, and thence back through the outer set of tubes H' to the opening,
whence it is led into the low pressure cylinder D.
Thus according as one or other of the several caps M M etc., is reversed or
turned through 90° the proportion of the tubes through which the air passes on
its way to the high pressure cylinder, or it may be to the low pressure cylinder,
or to both cylinders can be varied, and consequently also the relative proportions
of the heating surfaces by which the air is heated.
In Fig. 3, for example, air is first passed through fourteen tubes and then
through eighteen tubes, but if the cap M³ be shifted, instead of cap M the air led

page_text: to the high pressure cylinder will pass only through ten tubes to the high pressure.
cylinder, and the air led to the low pressure cylinder will pass through twenty-two
tubes.
The amount of heat employed can be regulated by suitably regulating the com-
bustion in the stove.
P
The several tubes, which are fitted in the lower chest N in an air tight
manner, are kept in position, at the top by a ring P which serves at the same time
as an upper cover to the stove. This ring is supported by stay bolts
that pass
through the lower chest N. As shown each set of four tubes (two inner and two
outer) are connected by one of the caps M. which can be drawn tightly down upon
the tubes 1, 2, by means of screw nuts on the bolts p each cap as hereinbefore
mentioned, connecting two outer tubes together and two inner tubes together or
the two outer tubes can be connected with the two inner tubes, according to the
position of the cap.
Fig. 4 shows a construction of a heating stove with fire place Q, in which the
proportion of the heating gases used can be varied. The heating gases escape
through a passage divided by a pivoted tongue R, into the heater proper S, S',
through heating coils T, Tin which the compressed air passes. One of the
heaters corresponds to one cylinder of the motor and the other to the remaining
cylinder. The proportion or amount of the gases of combustion passing through
cach heater, is regulated by adjusting the position of the tongue R. This adjust-
ment can if desired be effected by hand or in an automatic manner by means of
the governor of the engine.
It will be readily understood without further description that in this arrangement.
it is possible also to vary the amount of the heating surfaces, by providing each two
tubes with a reversible cap U capable of being shifted as in the arrangement.
illustrated in Fig. 3.
At the right hand side of Fig. 4 there is shown one of these caps U turned
through an angle of 90° from that of the others, so as to thereby cut out two of the
tubes T.
In lieu of the vertical stove indicated in the drawings for combustion of solid
fuel, any other suitable construction of stove or heater may be employed adapted
for burning gaseous or liquid fuel or to be heated by steam etc.
The arrangement of the stoves for motors with more than two cylinders will be
readily understood from the foregoing description.
Having now particularly described and ascertained the nature of the said.
invention, and in what manner the same is to be performed, I declare that.
what claim is
1. In a compressed air motor having two or more working cylinders, regulating
the heating of the air before its admission to the several working cylinders, (a) by
varying the relative proportions of the heating surfaces of the heating stoves in
connection with the respective working cylinders; or (b), by varying the proportions.
of the amounts of heat supplied to such heating surfaces; or (e), by simultaneously
varying both these proportions.
2. For the purpose referred to in the preceding claim under (a), a combined or
composite heating stove containing two sets of tubes (H & H'), that can be con-
nected together in various ways by means of movable caps (M), substantially as
hereinbefore described with reference to Figs. 2 & 3 of the drawings annexed.
3. For the purpose referred to in Claim 1 under (b and c), a combined or com-
posite heating stove containing two sets of tubes (T and T¹) provided with
adjustable caps U, arranged within heating chambers S, S', and heated from a
common source of heat, the arrangement being such that the proportion of the
amounts of heat supplied to the two sets of chambers and tubes can be regulated by
a regulating tongue or device R; and the extent of the heating surfaces of the

page_text: separate sets can be varied by the caps U substantially as herein described with
reference to Fig. 4 of the drawings annexed.
Dated this 21st day of February 1891.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.