NEW AND USEFUL IMPROVEMENTS IN VACUUM PUMPS
Year: 1881

page_text: LETTERS PATENT to Lorentz Albert Groth, K.G.V., Civil Engineer, and
Proprietor of the Scandinavian Patent Office under the Firm of L. A.
Groth & Co., 97 Finsbury Pavement London EC., for an Invention of
"NEW AND USEFUL IMPROVEMENTS IN VACUUM PUMPS " A communication
from abroad by Henry Goebel and John William Kulenkamp of the City,
County and State of New York ITS A
PROVISIONAL SPECIFICATION left by the said Lorentz Albert Groth at
the Office of the Commissioners of Patents on the 19th December 1881.
LORENTZ ALBERT GROTH, K.G.V., Civil Engineer and Proprietor of the Scan-
dinavian Patent Office under the Firm of L. A. Groth & Co. 97 Finsbury
Pavement London E.C., NEW AND USEFUL IMPROVEMENTS IN VACUUM PUMPS "
A communication from abroad by Henry Goebel, and John William Kulenkamp, of
the City, County and State of New York, U.S.A.
This Invention has reference to an improved vacuum pump, based on the well
known Geissler system of vacuum pumps, but adapted to render the operation of
the same mechanical, so that unskilled hands may operate the pump and evacuate
electric lamps and other vessels in a rapid and reliable manner and the Invention
consists of a Geissler pump provided with an air discharge valve at its upper end,
the whole pump being supported on a pivoted frame which is oscillated by means
of a hand-lever, so as to throw a body of mercury into a trough-shaped horizontal
portion of the evacuating tube and form therein a mercurial seal. The mercury
receptacle, connected with the pump, is adapted to be raised to the proper height
by a suitable hoisting mechanism, until the surplus mercury passes through the
discharge valve at the top of the pump and back again by a connecting tube to the
vertically guided mercury receptacle
Upon the lowering of the mercury receptacle the pump is returned into normal
position and ready for evacuation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lorentz Albert Groth in the Great Seal Patent Office on the
17th June 1882.
"
LORENTZ ALBERT GROTH K.G.V Civil Engineer and Proprietor of the Scan-
dinavian Patent Office under the Firm of L. A. Groth & Co. 97 Finsbury
Pavement London E.C NEW AND USEFUL IMPROVEMENTS IN VACUUM PUMPS"
A communication from abroad by Henry Goebel and John William Kulenkamp of
the City, County and State of New York, U.S.A.
This Invention has reference to an improved vacuum pump based on the well
known Geissler system of vacuum pumps but adapted to render the operation of
the same mechanical so that unskilled hands may operate the pump and evacuate
Electric Lamps and other vessels in a rapid and reliable manner.
The Invention consists of a Geissler pump provided with an air discharge valve
at its upper end the whole pump being supported on a pivoted frame which is
oscillated by means of a hand lever so as to throw_a_body-of-mercury-into-a-trough-
shaped horizontal portion of the evacuating tube and form therein a mercurial seal.
The mercury receptacle connected with the pump is adapted to be raised to the
proper height by a suitable hoisting mechanism until the surplus mercury passes
through the discharge valve at the top of the pump and back again by a con-
necting tube to the vertically guided mercury receptacle. The pump is returned
into normal position and is ready for evacuation upon the lowering of the mercury
receptacle.
The accompanying Drawing represents a front elevation of this improved vacuum
pump.
A in the Drawings represents a vertical support or stand to which is pivoted the
supporting frame B of a Geissler vacuum pump C, to the lower part of the pivoted
frame B is applied a connecting rod d and a hand lever b by which the frame B
may be oscillated to a certain extent as required by the pump
The upper part of the Geissler pump C is provided with an upwardly opening
discharge valve d and above the same with a cylindrical tube d¹ which is open at
the top and provided above the valve d with a short downwardly extending tube e
which connects with a mercury reservoir D. supported in a cage D'.
The reservoir D and cage D' are raised or lowered in vertical guides D' by a
suitable hoisting mechanisin E.
The lower end of the Geissler pump C' is connected in similar manner as the
upper end by a flexible tube el with the lower end of the mercury reservoir D the
tube being of sufficient length to provide for the distance required in hoisting the
reservoir
To the upper end of the Geissler pump C below the valve d is connected the
evacuating tube F by a trough shaped portion F' which increases in depth as it
approaches the neck of the pump and which extends nearly at right angles to the
main part of the tube F. The connecting portion F is made widest close to the
point of connection with the Geissler pump C so that the mercury within the
trough shaped portion F will be thrown over towards the angular connection with
the main tube F and form there a mercury seal which prevents positively the
passage of air to the Geissler pump while admitting the charging of the same with
mercury from the reservoir D preparatory to working the pump.
The charging of the pump is accomplished by raising the mercury reservoir up
to and above a level with the upper part of the pump C until the mercury passes
through the valve d and communicating pipe e back to the reservoir. The
reservoir is then lowered and the pump frame thrown towards the left. The play

page_text: of the pump will then begin in the usual well known manner, it evacuating the
electric lamps or other vessels sealed on to the upper end of the ovacuating tube F.
The main part of the evacuating tube F is inade somewhat higher than the
barometric height of a column of mercury exposed to atmospheric pressure so that
the pressure within the pump may be readily observed by means of a barometer B¹
arranged sideways of the evacuating tube F on frame A.
It is preferable to expose the lamps or vessels before and during evacuation to
the heat of a gas burner G arranged at the upper part of the frame A so as to
expel the moisture contained in the air within the lamp bulbs which hitherto was'
allowed to remain in the same.
Another
The main advantage of this improved vacuum pump is that the pump contains
no ground glass stop cocks of any kind which are always a source of leakage, they
forming to some extent the weak points of pumps for producing vacua.
advantage is that the operation of the pump is entirely mechanical and can be
attended to by inexperienced hands which is an important feature when large
numbers of electric lamps have to be evacuated.
Having now described the nature of the said Invention and the manner in
which same is to be carried into effect I would have it understood that what I
claim is
1st. The combination of a Geissler vacuum pump having a discharge valve at
the upper part and an evacuating tube connected thereto below the valve with an
oscillating supporting frame and a vertically moveable mercury reservoir sub-
stantially as herein before described and illustrated in the Drawing.
2nd. The combination of a Geissler vacuum pump applied to an oscillating sup-
porting frame and having a discharge valve at the upper end with a mercury
supply reservoir with pipes for connecting the upper and lower ends of the Geissler
puinp with the supply reservoir and with means for hoisting the latter substantially
as hereinbefore described and illustrated in the Drawing.
3rd. In a Geissler vacuum pump the combination of a Geissler pump C having a
discharge valve d at the upper end with an oscillating tube F connected thereto
below the discharge valve by a trough shaped portion F1 which increases in depth
below the pump and extends at right angles or nearly so from the main part of
the evacuating tube F substantially as and for the purpose set forth as hereinbefore
described and illustrated in the Drawing hereto annexed.
In witness whereof I the said Lorentz Albert Groth have hereunto set
my hand and seal this Fourteenth day of June in the year of our Lord
One thousand eight hundred and eighty two.
חו-מ
ENTZ ALBERT GROTH.
(L.S.)