Machine Makers.
Year: 1899

page_text: Date of Application, 16th Sept,, 1899-Accepted, 28th Oct., 1899
A communication by THE VEREINIGTE MASCHINENFABRIK AUGSBURG UND
MASCHINENBAUGESELLSCHAFT NÜRNBERG A.G., of 24, Kesslerstrasse, Nurem-
berg, in the Empire of Germany, Machine Makers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, Civil 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 follow-
ing statement:-
In operating cylindrical blowing engines, the motor has at present as a rule
to develop varying power corresponding to the actual air pressure. This cir-
cumstance is therefore unfavourable to the use of gas.engines for operating such
machines for the reason that the useful effect of gas engines possesses its highest
power with the largest charge.of gas and a falling power with a reduced charge
of gas. The
gas engines employed for operating cylindrical blowing engines can
therefore only work economically with the highest air pressure, whilst with a
lower normal air pressure they work disadvantageously.
This invention has for its object to avoid the above drawback, by creating a
cylindrical blowing engine in which the consumption of power of the motor
remains constant within certain limits, even with varying air pressures, so that
the gas engine serving for operating the machine can always work with full
charges.
It is endeavoured to obtain this object in a very simple manner by arranging
special equalizing or compensating chambers at both ends of the blowing
cylinders, considerably exceeding in size the otherwise usual dead spaces so that
the total cylinder contents considerably exceed the contents of the chamber
traversed by the pistons. That by such an arrangement the consumption of
power may be maintained approximately constant within given limits for vary-
ing air pressures is evident from the following consideration.
In the accompanying drawings, Figure 1 is a diagram in which a b c d repre-
sent the air pressure diagram for a blowing cylinder, the dead space of which
is of the moderate size hitherto endeavoured to be obtained.
On the descent of the air pressure from p max. to p min. the air pressure
diagram a bef is obtained and it is evident that with the decrease of the air
pressure the consumption of work has also become smaller.
Figure 2 shows a diagram for a blowing cylinder, the dead space s of which
is so great that on compressing the air drawn in at atmospheric pressure, the
highest air pressure p max. is reached at the point c that is to say at the dead
point of the piston. On the return of the piston, the air will then again expand
to the line of compression c b so that the work apart from mechanical friction
and the actions of heat is equal to nil. If however in this machine the necessary

page_text: air pressure diminishes, and sinks to about p min., there is obtained the air-
pressure diagram g bef, from which it is evident that with a very large dead
space, the consumption of power will be greater on the lowering of the air
pressure.
:
As however in consequence of a lowering of the air pressure with a small dead
space the consumption of power decreases, with a large dead space on the other
hand, it increases, and therefore it is possible to determine for each blowing
engine a clearly defined size of the so-called dead space s in which, within fixed
limits of air pressure p max. to p min. which may be determined, the necessary
consumption of work remains approximately constant. Figure 3 shows the
diagram of such a cylindrical blowing engine. The maximum air pressure
p max. corresponds. to the diagram surface a b c d, the minimum air pressure
p min. to the diagram surface gbe f. If the equalizing chambers, to be
arranged at the ends of the cylinders, are of such a size s that the diagram sur-
faces a b c d and g bef are equal to one another, the consumption of power
remains approximately constant within the limits p max. to ? min. as the sinking
of the manometric effect corresponding to the surface ia ad is each time
equalized or counterbalanced by an equal rise of the volumetric effect correspond-
ing to the surface ga if and vice versa. The gas engine serving for operating
the machine can therefore always work with a full gas charge, and with the
greatest useful effect.
The equalizing chambers may be formed either as prolongations on both ends
of the working cylinder, or as separate containers connected by pipes or passages
with the ends of the working cylinder. A machine of the first kind is shown
in Sheet 2, Figure 4. The blowing cylinder a has here at both ends prolonga-
tions forming equalizing chambers 9, so that the whole cylinder has a consider-
ably greater length than would correspond to the space traversed by the piston
indicated by the end positions of the piston as shown.
If in addition the air pressure limits p max. and p min. lie very wide apart,
it may be necessary to alter the sizes of the equalizing chambers during the work-
ing of the machine. Such an arrangement is shown in two forms of construction
in Figures 5 and 6. In Figure 5 a small cylinder 6 is arranged at the side of
the blowing cylinder a, the ends of which small cylinder are connected with those
of the working cylinder a by means of pipes c. In the side cylinder b there are
located two pistons d, the piston rods e of which are provided with right and
left hand threads at the ends facing one another, and connected with one
another by means of a nut f. By turning the nut, the pistons & may therefore
be equally moved outward or inward, so that the size of the equalizing chambers g
may be easily altered during the working.
In the form of construction shown in Figure 6, the equalizing chambers are
formed by two separate containers b, each of which is connected with one end
of the working cylinder a by means of a pipe c and which are partly filled with
water or other suitable fluid. At the bottom both vessels are connected with
one another by means of a pipe in which a two way cock i, serving for
admitting the liquid, is arranged. When the liquid has been run in, the con-
nection between the two chambers is interrupted by turning the cock The
two cocks located at the bottom of the vessel b serve for drawing off the liquid.
By suitably operating the cocks i and k, the level of the liquid in the vessels b
may be suitably raised or lowered, and thereby the size of the equalizing chambers
be altered during the working of the machine.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated
to me by my foreign correspondents, I declare that what I claim is :-
:-
1. A cylindrical blowing engine, characterised by the provision of separate
equalizing chambers (g) lying wholly or partially inside or outside the cylinder
for the purpose of causing the consumption of power by the motor to always

page_text: remain the same even with variations in the air pressures in such a way that the
total capacity of the cylinder suitably exceeds the capacity of the chamber tra-
versed by the piston and any sinking (i e c d Figure 3) of the manometric effect is
equalized within fixed limits (p max. and p min.) by an approximately equal
increase (gai f) in the volumetric effect and vice versa, substantially as
herein before described.
2. In a blowing engine such as herein before described, making the size of the
equalizing chambers (9 Figures 5 and 6) readily adjustable and if desired during
the working of the machine, by means of special arrangements, such for instance
as adjustable pistons or an adjustable supply or admission of liquid, substantially
as hereinbefore described.