Year: 1898

page_text: I, EMILE PULSFORD, of 10, Rue Taitbout, Paris, France, Engineer, do hereby
declare the nature of this invention to be as follows:-
My invention relates to an improved pneumatic or air pump, characterized
mainly:
1. By having several successive pump barrels of decreasing capacity, the largest of
which communicates with the space to be exhausted, and is connected with the others
by passages or tubes adapted to be opened and closed by means of distributing
slide valves, no lift valves, or clack valves, being employed, and the plungers
of any two successive pump barrels being so arranged as to work always in
opposite directions.
2. By a special arrangement whereby the entry of air is prevented both along
the plungers and near the distributing means, and consisting in the introduction
of, or covering with, oil, the outer face of the plungers, as well as the dis-
tributing gear or mechanism.
The pump barrels, which may be arranged vertically side by side, communicate
one with the other through passages starting from their lower ends and passing
through distributing boxes, and the first or largest pump barrel communicates
through a tube, in connection with its distributing box, with the space to be
exhausted, whilst the last or smallest pump-barrel discharges into the atmos-
phere through a tube provided with a clack or similar valve.
The pump barrels are open at top, and are longer than required by the stroke
of the plungers so as to enable a layer of oil to be carried by each plunger
for the purpose of preventing atmospheric air entering at this end, the other
end being protected against the entrance of atmospheric air by placing the
bottoms of all the barrels, together with their distributing boxes and valves,
into a tank containing oil.
The pump barrels may be arranged to oscillate, and have their plungers rigidly
connected to plunger rods attached directly to a crank shaft; or the pump
barrels may be stationary, and the plunger rods be connected either to the
plungers by a swivel joint, or may be fixed in the plungers, as before, and
operated by connecting rods from the crank shaft.
When oscillating pump barrels are employed, the connecting tubes would be
made of flexible material.
The distributing means may advantageously consist of a casting, provided
with passages or ports, and connected to the base of the pump barrel. Against
this casting works an oscillating disc or valve having a channel or conduit
adapted to establish, or to intercept, communication between the aforesaid
passages or ports. One of these passages or ports opens into the pump barrel
and draws in the air from the space to be exhausted, and the others, after com-
municating with the other barrels, open into the atmosphere. The oscillating
lises or valves are operated by suitable means and are controlled in accordance
PS11

page_text: with the stroke of their respective plungers, for example, these means may be
rods provided with stops and connected with the plungers.
The required capacity of the successive pump-barrels may be obtained either
by giving the same stroke to all the plungers and decreasing the diameter of
the successive barrels, or by giving the same diameter to all the barrels and
different strokes to the plungers.
Improvements in Pneumatic or Air Pumps.
I, EMILE PULSFORD, of 10, Rue Taitbout, Paris, France, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying drawings and to the letters
and figures marked thereon, that is to say:-
This invention relates to pneumatic or air pumps, and is mainly characterised
by the following features, that is to say:-
1st. By having successive pump barrels of decreasing capacity, the largest of
which is in communication with the space to be exhausted, and is connected
with the others by passages or tubes adapted to be opened and closed by means
of distributing slide valves, thus dispensing with lift valves or clack valves, the
plungers or pistons of any two successive pump barrels being so arranged as to
move always in opposite directions.
2nd. By the special means whereby any entry of air is prevented past the
plungers or pistons and near the distributing devices, and consisting in covering
with oil the outer face of the said pistons, as well as the distributing gear or
mechanism.
The accompanying drawings show, by way of example, such an air pump
having three pump barrels arranged in succession, the distributing slide valves
of which are formed by oscillating discs or plates kept on their seats by atmo-
spheric pressure.
Fig. 1 shews a partial sectional elevation of the general arrangement of the
pump,
Fig. 2 a side view of the lower end of one of the pump barrels, and.
Fig. 3 the same in horizontal section.
In the two last figures, the oscillating or distributing disc is, for greater
clearness, shewn detached from its seat.
The pump barrels A, A1, A2, are arranged vertically, side by side, and com-
municate one with the other through passages starting from their respective
bases and passing into the distributing boxes. The pump barrel A further
communicates through the tube T with the space to be exhausted, and the barrel A'
with the atmosphere through a tube T provided with a clack valve (or with
a lift valve).
The pistons B of these barrels are operated by means of a shaft D, having
cranks set at 180° to each other, so that when the pistons A and A2 are at the
upper end of their stroke that in A' is at the lower end of its stroke.

page_text: The three pump barrels are single acting and are shewn as being of equal
length, and the pistons are supposed to all have the same stroke, but the in-
ternal diameter of the barrel A is greater than that of the barrel A', whilst this
latter is greater than that of A. In this manner the capacity of the barrels
decreases from A to A².
The same result could be obtained with barrels of equal internal diameters,
by reducing the stroke of the pistons in A¹ and A²
The three pump barrels are open at top, and, in order to prevent the entry
of air at this end, are made longer than the stroke of the pistons, and the upper
faces of these latter are covered with a layer of oil.
The pump barrels may likewise be made either to oscillate, as in the
arrangement shown in the drawings (where 0 0, is the common axis of oscilla-
tion), or they may be stationary. In the latter case, the piston rods would be
connected to the pistons by means of a pivotal joint, or be provided with con-
necting rods at their upper ends.
To prevent the entry of air at the distributing devices, the lower ends of the
pump barrels are immersed in a tank G filled with oil.
The tubes T, T¹, T, are made of flexible material so as to permit of the pump
barrels oscillating.
The distributing gear or mechanism being identical in all three barrels, it
will be sufficient to describe only one, say that in connection with A.
The base or lower end of the pump barrel A is formed by a casting provided
with internal passages, a, b, c, of which communicates with the space to be
exhausted through the tube T, (Fig. 1), b with the second pump barrel A¹
through the tube T¹ (Fig. 1), and c with the base of the barrel A. The oscillating
disc H forming the distributing valve is provided with a passage d, which
establishes communication between the passages a and b during the up stroke
of the piston, and closes it during the down stroke; this disc is actuated by a
rod J, the lower end of which is connected to a crank pin fixed on the outer
face of such disc.
The barrels A and A³ are likewise provided with oscillating discs H¹ and H
respectively.
A rod J in connection with the barrel A carries two stops K and L, and slides
with appreciable friction in a collar M fixed on the piston rod. During its
stroke, the piston moves the rod J until the stops strike against the projection N.
During the remainder of the stroke of the piston the rod J slides in the
collar M.
Similar rods J and J, collars M¹ and M³, and stops K1, K2, and projections N¹
and N, are to be found in connection with the pump barrels A' and A².
Fig. 1 (pumps A and A²) and Figs. 2 and 3, shew the position of the parts
during the up stroke of the pistons.
b
The lower end of the pump barrel A is in communication with the passage
through the passage c, and with the passage a through the passage of the
oscillating disc. The piston B, on rising, draws in air through the passage a
from the space to be exhausted; the passage establishes communication with
the distributing box of the second pump barrel A¹. This second box is identical
with the first one and is provided with three similar passages, but as the piston
in A is descending while that in A is rising, communication between the pas-
sages in said second box will be closed, and that between the passages a and b
in the first distributing box will be open.
The passage b, and consequently the pump barrel A, is therefore only in
communication with the barrel A' during the descent of the piston in A corre-
sponding to the rise of that in A, at which moment communication is closed
between A and the space to be exhausted, and the air contained in A is forced
or driven into A¹.
It will thus be seen that with the exception of the exhaust opening in the
pump barrel A, the distributing devices comprise neither valves nor clacks, the

page_text: working of which in the case of highly rarefied air is always defective owing to
their weight.
The capacity of the three barrels decreasing from A to A³, the rarefied air
contained in A is successively compressed by passing from A to A¹, and from A
to A This allows a more ready exhaust on the down stroke of the piston
in A and distributes the work over the various pistons.
The number of pump barrels may be varied at will, two however being the
minimum.
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. An air pump, characterised by the combination of several successive single
acting pump barrels of decreasing capacity (the largest of which is in com-
munication with the space to he exhausted, and the smallest with the atmo-
sphere) connected to each other by passages or tubes opened and closed by dis-
tributing valves in the form of discs or plates turning about their centres and
working without the intervention of lift valves or clack valves, the upper face
of the pistons and the distributing devices being covered with or immersed in
oil in order to prevent the entry of air, substantially as set forth.
2. My improved pneumatic or air pump, constructed and operating substan-
tially as hereinbefore described and shewn in the annexed drawings.
Unted thio 974h lov of Ondation 1000
Dated thia 2741
October 1800.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, & 5A, Market Street, Nottingham,
Agent for the Applicant.