Improvements in Air-pumps and in Apparatus connected therewith
Year: 1891

page_text: OUMI LEID DI MUIFICATION.
Improvements in Air-pumps and in Apparatus connected therewith
1, AUGUSTIN STANISLAUS GHOSH, of No. 85, Sinclair Road, West Kensington,
London, Student, 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 :—
My invention consists of a new method of constructing air-pumps. The drawings
sent give a vertical section of the pump.
0
This air-pump consists of two stout barrels in which two pistons P and P¹ move
up and down, and close the barrels air-tight. Between the barrels and the receiver
(or the vessel to be exhausted) is a conduit which terminates in the bottom of the
barrels in two small conical apertures. These apertures are closed by two small
conical valves and ; these latter are fixed to metal rods which work air-tight
but with gentle friction in the pistons P and P. P and P¹ are circular discs into
which fit exactly and air-tight two valves V and V₁. These valves are truncated
cones and are fixed to two rods R and R¹ which pass through small round openings a
and a at the top of the piston rods. In the rods R and R¹ are fixed two small
discs 6 and b. Between a and b, a' and b¹ are two small spiral springs 5 and 8¹
respectively, which serve to keep down the valves V and V. The piston rods have
at the top two buffers B and B¹ in which are two strong spiral springs S and S¹.
Above the buffers, the rods are attached to the handle-rod A. A' which works on a
pivot at C. From A A¹ hang down two rods D and D¹ which can only swing in
the plane of the paper, but which are prevented from coming nearer the barrels by
two plates E and E¹ which are fixed to the handle-rod. The rods D and D' are
kept against E and E' by two light spiral springs F and F' which are attached to
two binding-screws G and G' sliding up and down the handle-rod but able to be
fixed in any desired place. Finally the rods R and R' are attached to two rods H
and H.
When a piston is ascending (as P¹ in Fig. I for instance) the valve V¹ will close the
piston by atmospheric pressure and the downward force of the spring s¹; the valve v¹
will be open and a portion of the air from the receiver will fill the barrel in which P¹
is ascending. The strong spiral spring S¹ in the buffer B' will be stretched full.
When the piston after reaching the top of the barrel, descends, the valve v (see
right-hand side barrel, Fig. I) will be closed. The valve V will be opened in the
first few strokes of the handle, by the compressed air under it; but when the air is
so rarefied as to be unable to lift up the valve V, then when the piston P is near
the bottom of the barrel, the rod D pressing upon the rod H, will raise the rod R
and thus open the valve V.
When the piston P has reached the bottom of the barrel (see Fig. II) the handle
rod A C will still descend for some time, the spiral spring $ (in the buffer B)
contracting. The valve V will also be kept open by the rod D pressing against
rod H; but before the piston P leaves the bottom of the barrel again, the valve V will
be closed by the rod D sliding off the rod H, as in Fig. II. As the handle-rod AC
ascends again, the spring S (in buffer B) will be stretched, and the piston P will
also ascend.
Thus at each stroke a definite fraction of the air in the receiver will be removed,
and the work is to be continued till the desired degree of exhaustion is arrived at.

page_text: 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 are the following features of novelty :-