neumatic Motor Engine
Year: 1892

page_text: Date of Application, 21th Oct., 1892-Accepted, 3rd Dec., 1892
CUMPLEIE DI BOLET
Pneumatic Motor Engine.
EDWARD MEIN 77 Woodford Road Forest Gate Essex, Engineer do hereby
leclare 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:
My invention consists of a specially constructed engine, for the utilization of
air as the motive power, the air being first of all partly compressed, and stored in a
reservoir on the motor, and afterwards caused to pass through a heating chamber
containing metal at a white heat, or even a molten state. by which means the
pressure or volume of the air is greatly increased by the absorption of heat before
it enters the cylinders.
In the accompanying four sheets of drawings, I have shewn an engine suitably
designed, for the traction of tram cars, but the general principle may be carried
out in any other form of engine where required, in this case it is so arranged that
the body of a car may rest on the frameing of the engine A. Fig. 1 Sheet 1,
which is supported by two pairs of wheels, so that its appearance in every
respect may resemble a horse car and be able to run in either direction without
turning it end for end.
I employ two independant engines each having a single high pressure cylinder B
and B 1 shewn in plan at Fig. 2 and in a side view at B 2 Fig. 1 Sheet 1 bolted
to the sides of the frameing. The two engines work on to the same shaft C Fig. 2
which forms one of the axles of the car. An advantage ariseing out of this
arrangement is, that either of them may be thrown out of gear by turning the
air off from its cylinder in the event of it being disabled on the road, and the
other engine would be free to bring the car to its destination without
external aid.
The means I employ to further augment the power of the air by the intro-
duction of heat constitutes the basis of my invention. At Figs. 3 and 4 Sheet 2
is shewn, by a side elevation partly in section and an end view respectively, the
heating chamber which I use for this purpose, it is formed by two steal tubes
an inner and an outer one D and D 1, Fig. 3 which are sealed up at their ends by means
of two flanges on whose faces have been turned wedge like recesses D2 and D3,
Fig. 3 to receive the previously turned ends of the tubes. The flanges are held in
their position by a series of bolts D4 and are screwed up till the ends of the
tubes are jammed sufficiently tight into the flanges to make a joint, it will be
seen that the bolts screw into one flange D5, but at the other end where it is
unavoidable they pass through the flange and a joint is made outside by turning
the nut conical to fit into a corresponding recess in the flange D 6. There is a
passage way right through the inner tube, the lower end of which is closed by a
door E and fastens by a catch E1, Fig. 4. The top end cau also be closed by
a lid E2, Fig. 3. The ends of the inner tube are enlarged D6 to allow for the
unequal expansion that will take place when first heated, the caseing E3 forms a
steam jacket hereinafter explained.
Having briefly described the construction of the heating chamber I will now
explain, the means employed, and the mode of heating the air. A. quantity of old
scrap iron previously made extremely hot or even converted into a molten state, in a
suitable furnace or cupola, is poured into the inner tube DD Fig. 3 which oweing
to it being very thin will become as hot or nearly so as the heated metal, the mean
temperature of which, during a journey of eight miles will not be less than
2000 degrees, "Fahrenheit," and as a volume of air is doubled by raiseing it's
temperature 490 degrees Fahrenheit," I am enabled by this simple means to
65

page_text: greatly increase the volume of the air before it enters the cylinders. The arrows
indicate the travel of the air through the heating chamber on its way to the
cylinders.
I may with a view to carrying out this idea more perfectly, cause the inner
tube D to be perforated with small holes, so as to allow the air to come in contact
with, and circulate through the heated metal, in which case suitable doors at each
end of the heating chamber would have to be used to avoid any leakage of air.
It is obvious that either of the two ways I propose to adopt for heating the
air, will not only be efficient, but simple and practical and economical for example,
assuming a number of engines to be worked, a suitable furnace would be built where
the engines are charged with air, and previous to making a journey the heating
chamber would be filled with hot metal and after the journey was completed, the
partially cooled metal would be allowed to fall into a suitable receptable to be
cast into the furnace and again reheated and so on "ad limitum."
Another feature of my invention relates to the cylinders I employ having no ports
or airways. A side view partly in section of the end of a cylinder is shewn at
Fig. 15, Sheet 3, but which are formed in the cylinder cover instead hereinafter
explained. The advantage ariseing from a cylinder so designed is, the saving of power
which would otherwise be lost, by the air on its entering the cylinder partially
expanding and filling the ports, before the motion of the piston is commenced.
The special design of the cylinder cover, I also claim as a part of the invention,
an end view, an end view in section, and a side view are shewn respectively in
Figs. 5, 6,.7, Sheet 3 it comprises a cylinder cover and the two valve boxes of the
inlet and outlet valves cast in one piece. The airways from the valves to the
cylinders are formed by cutting a hole through the cover G, G 1, Fig. 6 and as
the length of the airways do not exceed the thickness of the cover, which is not
more than half an inche, no perceptible loss of power can be caused by them,
if the valve boxes were cast separately from the cover, it would necessitate a
joint being made for each valve box either on the cover or on the body of the
cylinder, which is a difficult thing to do, and which would entail the possibility
of the joint giving way at any time, both these objections are done away by
casting the valve boxes on the cover, in addition to rendering the engine more
perfect by its greater simplicity.
Another part of my invention consists in the mechanism I employ to operate
the valves, and to enable me to increase at will the volume of air admitted into
the cylinder, so that I can proportion at any moment, the power of the engine
to the resistance it has to overcome and also to gradually increase the volume
admitted into the cylinder to compensate for the gradually diminishing pressure
in the reservoir, and further to enable me to work the air expansively. In order
to accomplish this I employ a revolving shaft running right across both the
cylinders, shewn at H, Fig. 2 Sheet 1 at each end of which is a sleeve H1 and H 2,
which is shewn on a larger scale in Fig. 8 Sheet 3 which also revolve with the
shaft, yet are free to slide along it laterally. This is effected by means of a key on
the sleeve fitting into an embedded key way on the shaft. On the sleeve reference
being had to Fig. 8 are projecting pieces or cams I, J, which revolve in front of
the friction rollers X and X1 in the ends of the spindles which open and close
the valves alternately, an end view of the sleeve is shewn at Fig. 9, K is the
spindle which operates the inlet valve, and L is the one that actuates the outlet
valve and it will be seen from the difference in the thickness of the cams that
the outlet valve is given a greater opening, this is necessary oweing to its increased
diameter. The rocking lever V is introduced to change the direction of motion of
the valve spindle. The design of the inlet and outlet valves are shewn at Fig. 6,
N and N1 respectively, it will be observed on reference to Fig. S that the cam I
which opens the inlet valves is angular in shape, consequently its position in front
of the friction roller will determine the duration of the opening of the inlet valve
or the amount of air admitted into the cylinder, or the period of cut off and
consequent degree of expansion, therefore by.drawing the sleeve a little to the

page_text: right or left, to alter the position of the cam, will more or less prolong the opening
of the inlet valve which admits the air into the cylinder. The cam which works
the outlet valve, is not angular but parallel in shape the mechanical result of which
is, that the moving of the sleeve on the shaft will not alter the duration of the
opening of the outlet valve, which under all circumstances must remain constant.
From Oto P which represents the two extremes of the opening of the inlet
valve, equals Q to R and the friction roller of the exhaust valve Lis lengthened
to avoid making the cam J the whole length from Q to R which answers the same
purpose. There are two sleeves, one for each cylinder and they are held in their
relative position by means of a tie-rod S, Fig. 2 Sheet 1 and in Fig. 10 Sheet 2
and they are moved along the shaft laterally by the reversing handle $1 to which
the tie rod is connected at S2. The reversing handle being secured at its bottom
end by means of a bracket & pin bolted to the frameing of the engine S3. In order
to reverse the engine throw the reverseing handle right over in the opposite
direction, which will bring another set of cams on the same sleeves into action
exactly like the aforesaid with the exception that they are fixed on the sleeve
diametrically opposite to them.
In combination with the revolving shaft H, Fig. 2 Sheet 1 and sleeves aforesaid,
I claim as a special feature of my invention the mechanism employed to cause the
motion of the engine's crosshead T, Fig. 11 Sheet 4 to revolve the shaft H;
Fig. 2. Sheet 1 and Fig. 11 Sheet 4 respectively, it consist in a rocking lever U,
working on a fulcrum Ul shewn in a side view at Fig. 11, and in plan- at
Fig. 12 Sheet 4 which is a shaft running from one side of the engine to the
other U 1, Fig. 2, Sheet 1. Referring again to Figs. 11 and 12 Sheet 4 the longer
or curved end of the lever U fits into a guide shoe U 2 fixed to and carried by the
crosshead Tyet is free to turn on its axis to accomodate itself to the varying
angularity of the lever which it guides. The guide shoe fits into a bush cast on
the crosshead shewn in section at Û 3 Fig. 13 and is secured by a washer and nut.
The mechanical result of the lever U being curved, & the guide shoe being fixed to
the crosshead which causes it to move in a straight line is, that the lever U is
alternately raised and depressed, and the motion thus obtained is communicated to
the crank pin U4 on the disc of the valve shaft H by means of a connecting
rod U 5 and the straight arm of the lever U. My object in curving the lever U is
to ensure that its motion shall be uniform with that of the crosshead, if it were
straight it would descend at an ever lessening speed as the guide shoe approached
the extreme end of the lever and vice versa.
I have prepared a diagram Fig. 14 showing how to find the right curve for the
lever U. let the line A to B represent the path of the guide shoe U 2 which divide
into eight parts and let the distance from C to E be the entire length of the curved
lever, and from E to F the arc described by it which must also be the required
stroke, which also divide into eight parts, then any radius that will exactly intersect
the fulcrum C and any two corresponding divisions on the lines A B and E F will
give the required curve, which in this case is the line D. from C to G represents
the straight arm of the lever U.
Another feature of my invention is that the cylinders are made sufficiently
large to allow the air being expanded down to atmospheric pressure, however
large the volume admitted into them, and as this point will be frequently reached
before the piston has completed its stroke, a vacuum more or less partial will, be
set up. To counteract this, the exhaust valves are so arranged as to act as vacuum
valves, when the air in the cylinder falls below the atmospheric line, and so balance
the resistance of the air acting on the exhausting side of the piston, by causing the
piston to act in equilibrio during the remainder of the stroke.
I also employ a novel device for lubricating the cylinders, which I term the
"vacuum lubricator," because the lubricant cannot pass into the cylinder except
when a partial vacuum occurs therein, a sectional view is shewn at F, Fig. 15,
Sheet 3 where it is fitted into the cylinder cover, but it may be screwed into any
convenient part of the body of the cylinder. W is the oil chamber, which is filled

page_text: by takeing out the plug W 1. X is a screw-down plug which determines the
amount of oil that shall pass into the cylinder by raising or lowering it on its
seat X1, beneath the seat of the aforesaid plug are two valves faceing each other,
whose length between the two faces A to B is greater than the distance between
the two seats on which they rest C and D, so that only one valve can be seated at
once, which is the case with the lower valve under all circumstances, except when
a partial vacuum occurs in the cylinder, whilst the lower valve is closed & kept
so by means of a spring X 2. The upper valve is open and the oil is free to
flow down into and fill the space between the wings of the valves, where it remains,
until the lower valve is automatically opened by the partial vacuum which
frequently occurs in the cylinder when the pressure of the air which in addition to
the spring 2 keeps the lower valve against its seat is removed, and it opens, and the
oil previously secreted between the wings of the valves flows into, or is sucked into
the cylinder through the passage X3. The upper valve closes simultaneously when
the lower valve opens, consequently no more oil can pass into the cylinder than
was previously secreted between the wings of the valves, and the amount required
to pass into the cylinder sufficient to lubricate it may be determined by the screw-
down plug X.
I have already mentioned that the cylinders, and heating chamber are steam
jacketed. A pipe Y communicates with all three shewn in the general plan
Fig. Sheet the object of which is to enable me to warm them before the
work of the day is commenced, by connecting them with the steam boiler at the
depôt, where the reservoir is charged with air, by means of a flexible tube. A cock
for this purpose is shewn at Z on the cylinder B, Fig. 2 Sheet 1. After having been
once warmed, they are kept hot during the remainder of the day by hot air
passing through them, and the reason for warming the heating chamber is because
it would not do to pour hot metal into it when quite cold.
Finally, an engine built according to my invention, would not weigh more than
one and a half tons. On reference to Fig. 2 Sheet 1 the arrows will show the
travel of the air through the heating chamber and by the regulator valve, R V, to
the cylinders, while the reverseing handle and the regulator valve may be worked
from the other end of the car, by a suitable arrangement of levers connecting
with R H to operate the reverseing handle, and with R X, to work the regulator
valve.
In order to avoid complicating the drawings, I have not shewn any more of
the engine than directly appertains to the invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The arrangement generally of a "Pneumatic motor engine" substantially as
herein before described.
2. The means and mode adopted to further augment the volume or pressure of
the air after it leaves the reservoir and before it enters the cylinders, by useing old
scrap iron, previously made very hot or even converted into a molten state, and
then poured into an inner tube of a heating chamber, and then causeing the partly
compressed air to circulate in an intervening space, between the inner tube
containing the hot metal, and an outer tube which forms the heating chamber.
I may also with a view to heating the air to the highest possible temperature,
perforate the tube containing the hot metal so as to allow the air to come in contact
with and circulate through the hot metal, substantially as herein described and
shewn more particularly at Figs. 3 and 4 Sheet 2.
3. The design of the cylinders having no ports or airways, substantially as herein
described and shewn more particularly at Fig. 15 Sheet 3.
4. The special design of the cylinder cover which comprises a cylinder cover and
the two valve boxes of the inlet and outlet valves cast in one peice, substantially as
herein described and shewn more particularly at Figs. 5, 6 and 7 Sheet 3.

page_text: 5. The mechanism employed to operate the valves which constitutes two sleeves
of peculiar form in combination with a revolving shaft on which they are free to
move laterally, substantially as herein described and shewn more particularly at
Fig. 2 Sheet 1 and at Fig. 8 Sheet 3.
6. The mechanism employed to cause the engine's crosshead to revolve the
aforesaid shaft substantially as herein described and shewn more particularly at
Figs. 11 and 12 Sheet 4.
7. The vacuum lubricator, substantially as herein described, and shewn more
particularly at F, Fig. 15 Sheet 3.
8. The means employed and the mode of warming the cylinders and the heating
chamber, by causeing a little steam to circulate through them, substantially as herein
described, and shewn more particularly at Fig. 2 Sheet 1.
Dated this 24th day of October 1892.
EDWARD MEIN.