Improvements relating to Vacuum Pumps.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements relating to Vacuum Pumps.
I, WILLIAM KENNEDY-LAURIE DICKSON, of New York City (841, Broadway),
United States of America, but at present residing at the Hotel Cecil, Strand,
in the City of Westminster, Engineer, do hereby declare the nature of this
invention to be as follows:-
The chief object of this invention is to provide a simple and effective pump
for use to produce the vacuum in the bulbs of incandescent electric lamps, but
the invention may be employed to produce a vacuum for any other purpose;
and the invention consists in the novel application of a coil of pipe to effect the
purpose desired.
In carrying out this invention, I provide two chambers side by side, one
being closed, serving as a vacuum chamber, and the other being open. A connec-
tion is made at the bottom between these two chambers, and the closed chamber
is connected with the article in which the vacuum is to be produced in any
convenient and suitable manner.
These chambers are about half filled with mercury, so that perfect seal is
obtained.
Within the closed chamber is mounted vertically a coil of pipe, one end of
which is open, and the other end is bent, and fits into the hollow portion of
an otherwise solid shaft, which shaft is supported and driven in any convenient
manner, and thus the coil is rotated.
The bearings of the shaft in the vacuum chamber will be below the surface
of the mercury, and will thus be sealed.
The coil will rotate partly in and partly out of the mercury, and every time
it comes out of the mercury it will take up a portion of the air in the vacuum
chamber, which air will be sealed in the tube as soon as the mouth dips in the
mercury.
A quantity of mercury will thus be taken up, which will serve as a kind of
piston to force the enclosed air before it, as the coil rotates.
Eventually, the air escapes at the end of the coil, and the mercury is conveyed
back by a pipe, or in any other convenient manner, to the open chamber, io
maintain the quantity of mercury in the vacuum chamber at normal.
Dated this 22nd day of December 1898.
NEWTON & SON,
Agents for the Applicant.

page_text: Improvements relating to Vacuum Pumps.
I, WILLIAM KENNEDY-LAURIE DICKSON, of New York City (841, Broadway),
United States of America, but at present residing at the Hotel Cecil, Strand,
in the City of Westminster, 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:-
The chief object of this invention is to provide a simple and effective pump
for use to produce the vacuum in the bulbs of incandescent electric lamps, but
the invention may be employed to produce a vacuum for any other purpose.
To this end, the invention consists in the novel application of a coil of pipe
to effect the purpose desired..
In the accompanying drawings:-
Fig. 1 shews in sectional elevation one mode of carrying out this invention.
Fig. 2 being a side view, with the cover removed;
Fig. shows a slight modification in the construction of the apparatus,
spur gearing being substituted for worm gearing.
A is an hermetically closed chamber of suitable dimensions, which may be
termed the vacuum chamber. At top, this chamber is provided with an inlet B,
and in the sides are bearings for a horizontal hollow shaft C.
Outside this chamber A, is a second chamber D, which is open to the air,
and which is connected with the chamber A by a pipe E. This pipe may enter
the chamber D at its upper part, to form an overflow pipe, and it connects with
the chamber A at the bottom.
Upon the hollow shaft C, and in connection therewith, is mounted a volute coil
of pipe F, one end of which is open, and the other end is connected with the
hollow shaft C, which virtually constitutes a lateral continuation of the pipe F.
The hollow shaft C projects thro' the side of the vessel A into the vessel D,
to which it is open, and it carries a worm wheel or a spur wheel G, which is
driven by a worm or a spur pinion suitably operated.
The chambers A and D contain mercury, which extends above the bearings
of the shaft, so that the latter are sealed against the passage of air.
In working the apparatus, the chamber A is connected at the point B with
the article to be evacuated, and the coil is caused to rotate.
During its rotation, the mouth of the coil will pass through the air space
in the chamber A, and will take in air, which will be sealed in the coil directly
the mouth dips again into the mercury. A kind of mercury piston to force
the enclosed air along the coil, as the coil rotates, is thus formed.
Eventually, the air and the mercury are discharged into the hollow shaft,
and they pass thence into the chamber D.
The quantity of mercury is thus, as it were, continually increasing in cham-
ber 1), and decreasing in chamber A, and the excess in the former runs back
into the latter by the over-flow pipe E, so as to keep the level of mercury normal
in the two chambers.
As the air in the vacuum chamber is taken up by the rotating coil, a corre-
sponding quantity of air is drawn into the chamber from the article to be
evacuated, until a perfect vacuum is produced both in the article and in the
chamber A above the mercury.
It will be obvious that the mechanical details of this invention may be modified
to a greater or less extent, according to the taste or knowledge of the manu-
facturer.

page_text: 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. A vacuum pump constructed, arranged, and operating as herein shewn
and described.
2. A vacuum pump, comprising a vacuum chamber to contain mercury, an
open chamber, also to contain mercury to the same level as in the vacuum
chamber, a tubular connection between the two chambers, a volute coil of pipe
mounted in the vacuum chamber on a hollow shaft, a hollow shaft forming a
lateral continuation of the coil, and projecting into the open chamber, and
means for rotating the shaft, as herein shown and described.
3. In a vacuum pump in which a volute coil of pipe connected with a hollow
shaft is rotated partly in and partly out of a quantity of mercury, sealing the
shaft bearing by the mercury as and for the purpose herein shown and described.
Dated this 12th day of October 1899.
NEWTON & SON,
Agents for the Applicant.