Improvements in and relating to Air Engines or Motors.
Year: 1892

page_text: Date of Application, 26th May, 1892-Accepted, 2nd July, 1592
COMPLETE SPECIFICATION.
Improvements in and relating to Air Engines or Motors.
I, JOHAN GUSTAF RICHERT, of Gothenburg in the Kingdom of Sweden,
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 :-
This invention is founded upon the fact that the energy of a given quantity of
gas is increased by being heated from without. If a quantity of gas for instance
weighing 1 kilogramme and having a pressure of 5 atmospheres is caused to pass
through a suitable heating device it will occupy a greater volume provided the
pressure remains the same. The quantity of gas thus expanded is of à greater
energy than the original one, that is to say the mechanical work that the same can
perform has increased, as this is a property of the pressure as well as the
volume.
The object of my invention is by means of supplying heat to a given quantity of
gas generally air, compressed beforehand, to increase the energy of the same and
in this way to obtain economy in working expenses, as compared with present rates,
for compressing the air which is afterwards to be heated and for developing the
power to be utilized for any desired purpose.
In the accompanying drawing the invention is illustrated as representing in plan
an installation for the development of pneumatic motive power.
W is an air vessel in which the air is compressed by means of a compressor M
which is moved by a smaller motor G for instance a gas engine or some suitable
hand motor. When the compressed air has obtained the required pressure the
supply of air through the pipe a is cut off between the air vessel W and the
compressor M which is thrown out of operation. From the air vessel a pipe b
communicates with a heater F and this is by means of a pipe e connected with an
air motor L. When passing through the heater F the temperature of the
compressed air is increased in consequence of which its volume is increased,
preferably under constant pressure, consequently the energy is increased in every
weight unit of air passing through the heater, so that the power developed in the
air motor L will by far surpass the power which would have been developed, if the
air had been led to the motor without heating. The heater F should be so
arranged that the quantity of heat which is imparted to the air may be regulated.
By arranging the heater in this manner the work developed by the motor may be
increased or diminished.
In order to further increase the power developed by the motor water may be
injected into the heater, which water will be transformed into steam.
The air motor must of course be arranged, with a due regard to the perfect
utilisation of the power stored up in the compressed and heated air.
The power developed in the air motor is used in the following manner. A portion
of the said power is utilized in pumping air into the air vessel to take the place of
that escaping from the air vessel to the heater, so as to maintain the pressure in
the said air vessel constant. This compression is effected in a compressor K from
which the compressed air is led to the air vessel W through a pipe d. The
remaining part of the power may be used in different manners as for instance for
driving a shaft. It may also be utilized in a compressor for forcing air into another
air vessel from which the air is led either to an air motor, provided like the herein
described motor with a heater, in order to store there its mechanical work or the
compressed air may be conducted directly to places, where the said air is required
for instance, for developing smaller quantities of power or for effecting the
reduction of temperatures. The heating need not necessarily take place in a heater

page_text: located outside of the cylinder but can also take place in or round the cylinder
or in or between the cylinders if the air is subjected to a double or multiple
expansion.
The cost of the power obtained in the manner above described is small compared
with the cost of that developed by any other system because the only fire to be
maintained is that utilized for the working of the heater. The consumption of coal
requisite for increasing the energy of the air in the air heater to such a point that
the increase in the development of its power will correspond to one horse power,
will amount to about 0.09 kilogrammes per hour, while for a corresponding increase
of energy in a steam boiler of a comparatively perfect construction there will be
consumed about 0.9 kilogrammes an hour.
The air, escaping from the motor L the temperature of which is very low in
consequence of the expansion to which it is subjected during its passage through
and from the motor is led to the compressor K in order to cool the same. In this
way an economy of power is obtained as there is no need to provide this arrangement
with any separate cold water pump for the said purpose. Should the air escaping
from the motor not be sufficient for effecting the requisite reduction of temperature
in the compressor, cooling water must of course be used. The quantity of the said
water need of course not be so great in this event as if the air were to be led off
directly into the atmosphere.
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. In a pneumatic motor in which the compressed air is given increased energy
by heating prior to its work in the motor cylinder and in which part of the power
developed is used for driving an air compressor, the arrangement of the pipe,
through which the air is led to the motor the same being connected only with the said
compressor so that the motor supplies itself with the whole quantity of air requisite
for performing its work.
2. In the arrangement above described the location in the conduct between the
compressor and the motor of an air vessel (W) and combined with the latter a
smaller independently driven air compressor (M) designed to produce in the air
vessel the air pressure requisite for driving the motor.
3. In the arrangement above described combining the outlet pipe for the air
expanded in the motor with the compressor in such a manner that the cold air
passing from the motor may effect the cooling of the air in the compressor.
Dated this 26th day of May 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.