A Method of and Apparatus for Obtaining a Mixture of Compressed Air and Steam, and Utilizing the same for Distributing Power in Factories.
Year: 1887

page_text: Date of Application, 11th Mar., 1887.
Specification Accepted, 22nd Apr., 1887.
COME17121.17 T
A Method of and Apparatus for Obtaining a Mixture of Compressed
Air and Steam, and Utilizing the same for Distributing Power in
Factories.
1, WILHELM SCHMIDT, civil engineer, of Brunswick. Germany do hereby declare
the nature of this invention and in what manner the same is to be performed, to he
particularly described and ascertained in and by the following statement :-
In large factories in which there are often many steam-engines working separately
from each other the steam required to feed them is generally not utilised very
rationally.
Owing to the smallness of such steam-engines complicated arrangements (in them)
such as the compound system, heating of the cylinders etc. are quite out of the
question. Moreover as these steam-engines are used very often at intervals of longer
or shorter duration it is not possible in most cases to furnish them with separate
boilers; they have therefore to be fed from one common central steam-boiler. But
to the loss necessarily occasioned by condensation in the feed-pipes and the respective
cylinders the steam is thus utilised in a still less rational way.
For the purpose of removing these drawbacks high pressure boiler-steam is first
used at a central point to compress atmospherie air. The steam expands thereby and
the exhaust steam of this engine, which has still a pressure of some atmospheres, then
mingles with the compressed air. This mixture of air and low pressure steam is
conducted to the separate engines and used as a driving power in them.
This method of utilising steam offers the following advantages:
High pressure boiler-steam can be utilised rationally at the central point for the
purpose of obtaining power. Low pressure waste-steam of a pressure suitable for the
small driving engines is likewise obtained there. But these small driving engines
also profit by the work rendered by the high pressure steam, for the result of this
work, namely the compressed air assists in driving them. The mixture of steam and
air is most suitable for avoiding and decreasing loss of power by condensation in the
feed-pipes and in the steam-cylinders of the separate engines. The mixing of air with
steam separates the particles of steam and reduces the condensing capacity of the
mixture.
This method of utilising steam may be turned a further advantage.
Whenever the separate steam engines consume much steam the pressure of this
steam and air mixture will decrease rapidly, but in consequence of this the counter

page_text: pressure of the air-pump and of the high-pressure cylinder will also relax rapidly.
The result is that the main engine works quicker and forces more steam and a greater
volume of air into the pipes leading to the separate driving engines. On the other
hand a smaller comsumption of steam in the driving engines necessarily causes the
main engine to work slower, for the counter-pressure of the air-pump increases then.
The working of the main engine is therefore regulated automatically in this method
of utilising the steam. The pressure of the mixture obtained in the feed-pipes is
mainly dependent on the proportion in which the cross section of the air-pump stands
to that of the high pressure cylinder.
In order to be prepared for any sudden increase in the consumption of steam a
steam-reservoir may be used. Low pressure steam coming from the high-pressure
cylinder may be led for this purpose into a water-reservoir. This low-pressure boiler
is heated by the steam led into it and may be used as an auxiliary steam generator
when the pressure in the feed-pipes decreases. Owing to its large volume of heated
water this auxiliary steam generator will be able to furnish a large volume of steam
even when the differences in pressure are slight.
Instead of all the waste-steam coming from the high pressure cylinder only part of
it need be mixed with the compressed air. The remainder of the steam may be used
for other purposes, for instance for compressing air, as it is represented in Fig. 1 of
the drawing.
In Fig. A represents the high-pressure cylinder. In it the steam expands for
instance from 12 to 6 atm. and then passes into the reservoir R. The air-pump is
driven by the high-pressure cylinder A. Part of the low-pressure steam that escapes
from A passes from the reservoir Rinto a feed-pipe leading to the driving engines.
Another part of this low-pressure sicam passes, after leaving the reservoir R, into the
low-pressure cylinder B. In the latter it expands from 6 Atm. to 0 and operates on
the air-pump 12. Air moistened with water is led by the rose-pipes opening
pipes to the two air-pumps 1 LA. Both these air-pumps LF force the compressed
air into the pipe q. The air then passes through the superheater and mingles with
the low pressure steam in the space a. This mixture of air and steam enters the feed-
pipe L.
and
"Fig. I and III show all the arrangements necessary for this method of utilising
steam. The low pressure steam resulting from the high-pressure cylinder A passes, in
this case, through the pipe y into the low-pressure reservoire N and heats the water
contained in the latter. The steam leaves the low-pressure reservoir by the pipe
and mingles with the compressed air conducted to it by the pipes m² m². m³ is the
feed-pipe leading to the separate driving engine.
377
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is:
1.) The method of using steam for compressing air first, then of mixing all the
waste-steam of the engine or part of it with the compressed air and of using this
mixture in separate steam engines for the purpose as described.
2.) In the method indicated in claim the using of compound or receiver engines
in such a way, that the waste-steam coming from the high-pressure cylinder is used
partly for the compression of air in a low-pressure cylinder and partly for being mixed
with the compressed air, for the purpose as described.
3.) In the method indicated in claim 1 the using of a water-reservoir N into which
the steam that escapes from the high-pressure cylinder is led, for the purpose of
obtaining a regulator of the heat.
n
1
A. KUHNT & R. DEISSLER,
Attorneys.