IMPROVEMENTS IN COMPRESSING AIR AND IN APPLYING THE SAME FOR THE PRODUCTION OF MOTIVE POWER
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the Office
of the Commissioners of Patents on the 27th January 1876. A communication
from abroad by Emile Heyler, of Paris, France.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN COMPRESSING AIR AND IN APPLYING THE
SAME FOR THE PRODUCTION OF MOTIVE POWER."
This Invention relates to a method of compressing atmospheric air to serve as
motive power for all kinds of stationary or portable engines.
The object of the Invention is to obtain compressed air without other resistance
than that of friction, that is to say, with such a slight expenditure of force that the
whole of the air thus compressed may be utilized for working an engine of any
kind, which engine will also itself compress the air required for working it without
any appreciable loss of power during the whole time it is in operation.
By means of this Invention neither fuel, water, heat, gas, or electrical apparatus
are required for working stationary or portable engines. Suppose that the air
contained in the greater of two cylinders having the same height, but the one
being of ten times greater capacity than the other, be transferred to the smaller
of the two cylinders, this air will have a pressure of 10 atmospheres. But in order to
thus transfer the air from the larger to the smaller cylinder, a considerable amount of
force is required, equivalent to 1 kilo. 033 per unit of surface or square centimetre
multiplied by the number of atmospheres obtained. No deduction is required for
the external atmosphere as both cylinders are open. To neutralize this force or
resistance it is necessary to oppose an equivalent force, and this is obtained
according to the present Invention by the aid of a piston in the manner I shall now
proceed to describe with reference to the accompanying Drawings; Figure 1 of
which represents a cylinder P of about 20 centimetres in length, open at top, and
in which works a piston p. The cylinder P is divided by measurements into ten
equal parts. Alongside the cylinder is a tube R whose sectional area is one-tenth
that of the cylinder P. This tube is open at top, and is also divided by measure-
ments into ten equal parts, each equalling the ten divisions of the cylinder P, and the
tube is also provided with a piston p¹, and it is placed in communication with the
bottom of the cylinder P. For each division the piston p is moved downward, the
piston p' is raised one division in the tube, and if we suppose 21 to equal the unit
of surface, that is to say, 1 square centimetre, the weight of the column of air
raised in tube R will be 10 × 1033, or 1033 kilos. = 10 atmospheres. The

page_text: pressure on this square centimetre will thus balance the pressure necessary to bring
the piston to the bottom of cylinder P. If pistons p, p¹, be connected to two
cranks placed in the same plane, but on opposite sides of a shaft, or on two shafts
connected by toothed gearing d, d', as shown in Figure 2, it will be evident that
the pressures being the same on both pistons they will balance each other in any
position which may be assigned to them. The fly wheel V will always furnish
sufficient power to overcome the friction against the sides of the cylinders, and the
apparatus may in this manner be charged by hand without much expenditure of
force up to a pressure of from 50 to 60 atmospheres.
Figure 2 shows a simple form of the apparatus. In this arrangement the pump P
is proved with two valves 8, s¹, for the admission of air to be compressed in
receiver P, with which it is placed in communication by pipes t, t¹. To avoid the
resistance of the compressed or non-compressed air, the receiver R is also fitted
with valves c, cl, operated by means of two semicircular cams on the shaft, valve c
being opened during the whole of the upward stroke of piston p¹ and valve J
during the down stroke.
When two receivers R, R¹, are employed as in Figure 3, one of these is charged
while the other is supplying its compressed air to the motor cylinder of the engine.
It will thus be necessary for the piston of receiver R to remain at rest while
that of receiver R₁ is working, and vice versa. When one pump and two receivers
are employed, slide valves or other means are used to distribute the compressed air to
its proper cylinder, but these are unnecessary when an equal number of pumps and
receivers are used, the number of these being varied according to the kind of engine
to be driven.
In order to apply the Invention, the valve chest C, Figure 3 of the motor
cylinder, is put in communication with receivers R, R¹, by pipes n, n', the shaft
driven from the motor cylinder being made to work pump P by means of toothed
gearing d, d, d, as shown, the intermediate wheel d being toothed on one half
only of its circumference.
Any other suitable means may also be employed for alternately working the
pistons of receivers R and R' so as to produce the necessary power for driving the
engine to which the apparatus is applied. The pipes n, n', should each be furnished
with a valve to prevent the compressed air in receiver R entering receiver R¹
through the valve box when one only is provided for the motor cylinder. Half a
turn of the fly wheel V suffices to charge the apparatus when all the air contained
in pump P, Figures 2 and 3, passes eith into receiver R or R¹ through pipes t, t¹,
and is there compressed.