Improvements in Compressed-air Generators.
Year: 1889

page_text: Date of Application, 2nd Feb., 1889
Complete Specification Left, 29th July, 1889-Accepted, 1st Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in Compressed-air Generators.
A communication from LEON BONTEMPS and PIERKE BOUTET, of 49, ruo Oberkampft,
Paris, in the Republic of France, Engineers.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.L.M.E. do hereby declare the nature of this invention to be as follows:-
--
The present invention relates to compressed air generators in which the air is
brought to the desired elastic tension by the utilisation of the pressure exerted by
columns of liquid on pistons of suitable dimensions.
This pressure being produced by columns of liquid acting on pistons of suitable
dimensions it is evident that the pressure can be varied at will as it depends upon the
height of the columns of liquid, tho diameter of the pistons and the density of the
liquid or liquids employed.
The generator consists essentially of two recipients of equal capacity which do not
communicate with each other and which alternately receive the pressure of a column
of liquid in such a manner that when the pressure is exerted in one of the said
recipients there is no pressure in the other.
When the pressure is exerted in one of the recipients a piston compresses the air
situated behind it and the compressed air can be used as desired by opening a suitable
valve. After this is done a simple changing of the valves produces the same effuct
on the other side i.e. in the other recipient.
This reciprocating movement may be effected by a lever actuated by a double
piston each side of which may be in one of the recipients.
As the air compressed and used must be replaced the before named twin pistons
in the recipients may be arranged to actuate two side pistons which alternately draw
air into the recipients. At the moment of the lowest point of the piston a slide
communicating with the recipient can be opened by the above said lever of the
immersed twin pistons.
Dated this 2nd day of February 1889.
W. P. THOMPSON & BOULT,
A grents.
COMPLETE SPECIFICATION.
Improvements in Compressed-air Generators.
A communication from LEON BONTEMPS and PIERRE BOUTET, of 49, rue Oberkampft,
Paris, in the Republic of France, Engineers.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.L.M.E., 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 relates to a system of compressed air generators in which the air is
brought to the desired elastic tension by the utilization of atmospheric pressure, or of
multiples of this pressure acting through the mediation of columns of liquid of
any desired height on pistons of dimensions suited to the effect required to be
produced.
The elastic tension of the air being produced, as has already been explained by
columns of liquid acting on pistons, the intensity can be varied at will, since this
intensity depends on the height of the liquid columns, the diameter of the pistons

page_text: upon which these columns act, and on the density of the liquid or liquids used, and
these three quantities may be taken arbitrarily.
The provisions and the working of this new system of generating compressed air
will be readily understood by referring to the annexed drawing which gives a full
view of it partly in section, and a portion of the sides being removed in order to show
the interior arrangement.
a is a tube containing a column of liquid of a height relative to the elastic force
that it is desired to give to the compressed air.
b is a cock at the lower end of the tube a the opening or shutting of which
determines either the starting, or stopping of the machine.
c is a pipe closing the tube a beneath the cock b.
d d' are tubes respectively prolonging each of the arms of the pipe c.
e e² are separate cisterns of equal capacity near to the bottom of each of which the
tubes d d respectively descend.
ff are valve connections between the ends of the pipe c with the tubes d d¹; when
these connections are alternately opened and closed the column of liquid contained
in the tube a exerts its influence first on one and then on the other cistern, but never
on both at the same time. Above the level of the water in the cisterns e e¹ is a layer
or cushion of air which balances the column a.
9 g¹ are twin pistons moving horizontally in cylinders arranged in the cisterns e e¹
and receiving in turn the pressure of compressed air which balances the column a,
this pressure is proportionate to the area of the pistons.
Pistons 9 9¹ are provided with a cup shaped leather packing and move within
corresponding cylinders integral with chambers e and e¹. A connecting rod suitably
links these pistons together.
hh passages through which the air escapes alternately; one of these passages
is completely closed when and during the whole time that the other is wide
open.
iare tubes conducting the compressed air (expelled alternately from each of the
cisterns e e¹) into two reservoirs.
jjare the said reservoirs whence the compressed air finds its way to the piston of
some motor in order to put it in motion.
k k¹ are tubes connecting the covers of the reservoirs ; j¹ with those of the
cisterns e e¹.
are openings for the return of the tubes k k¹; one of them is completely closed
all the time that the other is wide open.
in m² are cocks fixed on the tubes kk' at the interior of the cistern e e¹.
nn¹ are ball floats.
o o¹ are the rods of the floats n n¹ for opening or shutting the cocks m m¹ according
as the water level rises too much or on the contrary remains normal.
By reason of the apertures or valves
closed and opened the air coming from the
cisterns e e¹ at the same time; if it were
occasioned which would hinder the action
balance itself because the pressure right and
would therefore be arrested.
for the return of air being alternately
tubes k k² can never get into the two
otherwise a counter-pressnre would be
of the pistons g g₁ the machine would
left would be equal and the progress
Pp are small floats for regulating valves each of which uncovers an orifice when
the liquid gets beyond a certain level and by which an excess of water escapes.
99 are cylinders of equal capacity in which the pistons
move.
are the pistons on which the liquid of one or the other of the columns z 2¹ acts
the pressure on each of which is greater than that of the central column a.
ss¹ are valves opening bottom upwards in the bottom of the cylinders 9 q'; one
of these valves opens for the purpose of admitting the outer air when the other closes
through the descent of the corresponding piston; this descent of the piston
compresses the air previously drawn in and which being brought to a greater tension
than that which exists in the cisterns e e¹ enters these last to compensate for the loss
of the air before used.

page_text: ttare tubes opening at one end above the bottom of the cylinders 9 9' and at
the other end communicating with the portion of the cisterns e e¹ occupied by
the air.
uu are slides alternately introducing the air forced out by the descent of the
pistons into the cisterns e e¹ and then letting it out again; one of the slides remains
wide open during the time the other is kept shut.
vis a lever for operating the slides.
a is the pivot of the lever v.
y is a link attached at one end to the piston rod or one of the pistons g g¹ and at the
other to the lower extremity of the lever v.
Tho upper end of the lever v moves in a groove of the rod A. of the slides between
two bearings which push at the same time all the slides now from right to left now
from left to right and by this means causes the orifices or valves to open and shut
these openings and shuttings being made as has been already explained in an inverse
and reciprocal manner for the two symmetrical parts of the machine.
During the time that the upper end of the lever takes to travel over the space
which separates the planes the slides remain in the position in which they had been
placed by the preceding oscillation of the lever; this period of time leaves the orifices
open and closed all the time necessary for the admissions and the expulsions to take place
freely, and so that the motive powers of the pistons can complete their entire course.
An arrangement of levers and cranks operated by the twin pistons 9 g¹ causes the
pistons r³ to rise and fall as the drawing shows. Besides, all the other joint mechanism
of the progress of the pistons 9 g' could be substituted for that.
The following description will enable their mode of operation to be more readily
understood;
The various parts being arranged as illustrated in the accompanying drawings and
the pistons g g and r¹ and slide-valves h, f, u and h³, f, u¹ respectively, occupying
the relative positions shown what takes place in the chambers e e¹ and the cylinders q q
is this; The slide-valve u being open the air which had been compressed in cylinder q
has entered chamber e to make up for the consumption of air during the previous
stroke of the "twin" pistons g and g' while slide-valve has closed by this time to prevent
the escape of the compressed air from the reservoir j. At the same time slide-valve f
being open the water column a exercises its pressure upon piston g which is, by this
pressure driven from left to right, right up to the end of its stroke. Piston g¹ being
connected with piston g by a connecting link, follows the movement of the latter piston
and is thus made to enter chamber el where it completes its stroke (as shown) at the
same time as piston g reaches the end of its stroke in chambers e.
In advancing within chamber e¹ piston g' displaces some water with the result that
the air above the water level is compressed. The aperture of being closed at that time
the water column a is cut off from chamber e¹. On the other hand the aperture ³ is
open and the orifice u¹ closed so that the compressed air contained within e' cannot
but escape through aperture h¹ and thence through tube passes into the storage
chamber j. Piston g³ in advancing within chamber e causes piston 71 to rise under
the action of the links and levers set in motion by its rod; and this piston in its turn
raises the column z¹ thus creating a vacuum in the space below it, which results in the
valves rising from its seat and admitting the external air.
As the piston g' completes its stroke and levers are shifted by its movement,
whereby the lever o' is caused to travel from left to right through the interval between
tappets or stops A of the valve rod, all that was closed on the left side opens and all
that was open closes. The opening on one side thus corresponding to the closing on
the other side and vice versa the same operations take place in their turn in chamber e
as have just been described in respect of chamber e¹ and inversely.
The engine will work in this manner so long as the cock is left open.
When the water level is raised within chamber e (or e¹) the water gange n
(or n¹) opens cock m (or m²), and when slide valve 1 (or 1¹) opens the air as it
proceeds from chamber; (or j¹) enables the water to escape through the orifices
controlled by the floater valves p p².

page_text: 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. The system of generating compressed air producing the compression of the
air drawn in from the outside by means of columns of liquid of a height chosen
arbitrarily and acting on pistons of diameter proportioned to the effect required to
be produced, as the substitution of air in a regular manner and with regard to the
loss which is incurred.
2. In this system of generating compressed air two distinct cisterns of equal
capacity such as e e¹ on each of which a column of liquid a acts alternately and
where twin pistons such as g g' of equal dimensions move in appropriate cylinders
placed in each of the cisterns respectively.
3. With the rod common to the twin pistons g g₁ a lever » controlling with a
single stroke all the slides and regulating the admission and exhaust of water and
air (ff, hh, luu¹) in such a inanner that the orifices of one of the cisterns e e¹
are always perfectly ready to be opened or closed in a contrary way to that which
is taking place in the other cisterns.
4. There where the reservoirs jj' of compressed air in combination with the
return tubos kk' bringing back the compressed air in the cisterns e e' when the water
in these cisterns has exceeded the normal level.
5. The automatic command of the return to the cisterns e e¹ of the compressed
air already stored up the said command being made by a float n or n¹ placed one
in each of the cisterns e e¹ in such a way that the introduction of the return air
cannot occur in both cisterns at once.
6. The floats p or p₁ having command over a valve to let out the accidental
excess of water in the cisterns e el.
7. The cylinders and pistons 99', r¹ acting like pumps to suck in the outer
air and drive it back into the cisterns e e¹ to replace the lost air; these pistons
being directed by the twin pistons 9 g¹ in such a
g
manner that the one rises and
draws in air whilst the other descends and forces out air.
8. The combination of the tube conveying the water into the cisterns e e¹ with
a cock 6 for determining or stopping the progress of the machine, a pipe cof
which each branch is prolonged by a tube d or d¹ and by the arrangement for
controlling the slides acting on the orifices f f¹ in virtue of which the column of
water a is put in alternate communication with the two cisterns e e¹ this com
munication not being able to exist with the one without being interrupted with
the other.
The whole substantially as herein described and illustrated in the accompanying
drawings.
Dated thi~ 20th
3000