Double Piston Engine.
Year: 1899

page_text: Date of Application, 2nd Nov., 1899-Accepted, 13th Jan., 1900
COMPLETE SPECIFICATION.
Double Piston Engine.
We, JULIUS GRAU, Mechanician, residing at present at Friedeberg, on the
Queiss, Burgstrasse, and KARL Böna, Dentist, also residing at Friedeberg on the
Queiss, Bahnhofstrass 269, in the Province of Silesia, Kingdom of Prussia, part
of the German Empire, do hereby declare the nature of this invention and the
manner in which it is to be performed to be particularly described and ascertained
in and by the following statement: --
This invention relates to power engines using pistons for the admission or
compression of the gas or fluid which is the carrier of the motive power or
the propelling agent properly speaking, and in particular to that class of engines
driven by steam, gas or the like fluids. The improvement forming the subject
of this invention comprises the use of a cylinder in which two pistons are
made to move in opposite directions, in combination with the use of a novel
and peculiar sliding valve which controls the admission and the pressure of the
fluid and by means of which the gross effect of the engine provided with these
improvements can be greatly enhanced.
Our invention will be easily understood from the accompanying drawings which
illustrate a form of construction embodying our invention.
In the drawings:-Fig. 1 is a longitudinal section of the main part of the
engine; Fig. 2 shows another form of construction as a longitudinal section;
Fig. 3 is a similar section of a form of construction the cylinder being open at
both ends.
will
Referring particularly to Fig. 1; a and b are the pistons which move in a
common cylinder e; are the piston rods; e is a guide block to which the
pistons are secured and by means of which they are made to move parallel
to the guides f, f. g is the valve casing which opens into the cylinder by
the openings h, i, k. The valve casing also contains the exhaust port 7. High
pressure steam is admitted through m. n is the sliding valve which moves
within the valve casing . In the position shown in the accompanying drawing
by way of example, the opening of the valve registers with the opening i
of the casing: upon the valve continuing its movement, the opening
be closed up and the outlets h', of the valve will become free to register with
the corresponding openings h, k, of the casing and thereby establish the con-
nection with the cylinder. is a pipe shaped projection of the sliding valve
open towards the steam admission port m and which is capable of longitudinal
movement within the stuffing box m² so that the high pressure steam cannot
enter the valve casing g but is only admitted into the interior of the sliding
valve n the displacement of which is effected through the piston rod o in the
usual manner by means of cam discs or otherwise.
Referring to Fig. 2. p is a double lever to which is attached the pitman q.
By means of this arrangement the power which results from the movement
of the right hand piston is transmitted to the left hand piston to which the
pitman connects at the point r. Thus it is evident that in this arrangement

page_text: the purchase acting in the point will be equal to the combined powers of
both pistons.
Referring to Fig. 3: s is the cylinder open at both ends in which the two
pistons 1, 2 of unequal diameter are moving. t is the opening for the admission
of the gas or steam while the consumed gases escape at t¹. is the sliding
valve which is steadied in its movement by the use of flat springs a¹ or by
other suitable means so as to make the valve move along the top of the
valve casing. The power exerted by the piston s¹ is transmitted directly to
the fly wheel by means of the connecting rod w, the piston 2 being connected
to the same fly wheel through the connecting links w¹, w² adding thereby to
its purchase.
The mode of operation of the mechanism will be apparent from this description
and from an inspection of the drawings.
By the arrangement of two pistons within the same cylinder of the engine the
gross effect produced will be approximately the same as though the size of the
piston had been doubled.
It is evident that each of the pistons may be used to work independently of
the other, thus for instance in employing the arrangement on steamers with
double propellers, each of the latter may be actuated by one of the said pistons.
It is further evident that for some purposes it is possible to combine the action
of both pistons upon the fly wheel so as to avoid the dead center, as is shown
in the modification Fig. 3. The lead of one of the pistons in relation to the
other may therefore by varied at will.
The form of construction illustrated in Fig. 2 of the accompanying drawing
is particularly adapted to engines of that class in the working of which all
jamming and jerking action has to be excluded as far as possible such as engines
on board ship,, engines for the construction of motor- or horseless vehicles and
the like. In view of the jamming being chiefly due to the sudden and vehement
impinging of the steam, explosion gas or other fluid acting as the propelling
agent, against the solid and unyielding bottom of the cylinder, the important
advantage which results from the exclusion of such solid bottoms in the present
invention which substitutes the sliding surfaces of the pistons in the place thereof,
the said pistons counteracting any jamming of the propelling fluid, will be readily
apparent.
A further advantage results from the possibility of applying the improvement
to engines of the ordinary type heretofore in use without any difficulty, a change
which will very often suggest itself when the engine will be found not to
come up to the desired mechanical power. In all such cases the gross effect of
the engine can be greatly increased at comparately small cost by the application
of the combination system of double pistons forming the subject of our invention.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare what
we claim is :-
1/. Improvement in piston engines of any type or construction comprising the
use of two pistons moving in the same cylinder in opposite directions to each
other, substantially as and for the purpose set forth.
2. In piston engines of any form and construction, the combination of two
pistons moving in the same cylinder in opposite directions with means by which
the movement of one of the pistons is transmitted to the other piston and the
purchase of the said piston is thereby increased, substantially as and for the
purpose set forth.
37. In piston engines the use of a hollow sliding valve (n), openings in said
sliding valve to control the admission of the propelling fluid, the said openings
registering with respective openings connecting the valve casing with the
cylinder of the engine, substantially as and for the purpose set forth.
4/. In piston engines of the type described, a valve casing (g), a hollow sliding

page_text: valve within the said casing and which is so placed as to be surrounded by the
waste steam or waste gases of the engine, substantially as and for the purpose
set forth.
5. In piston engines of any type and construction, two pistons moving in
opposite directions, a valve casing for the control of the admission of the pro-
pelling fluid, a hollow sliding valve within the said casing and means to transmit
the motion of the pistons to a fly wheel or to any other part of machinery,
substantially as and for the purpose set forth.
6/. In piston engines of any type or construction, two pistons of unequal
diameter and moving in opposite directions to each other in combination with
a sliding valve being kept in contact with the top of the cylinder by flat springs
or other suitable means, substantially as and for the purpose set forth.
7/. In piston engines of the type described, a cylinder open at both ends, two
pistons within the said cylinder and moving in opposite directions to each other,
substantially as and for the purpose set forth.
Berlin, Germany, this 27th day of October 1899.
WALTER FOLKMAR,
Agent to Applicants.