IMPROVEMENTS IN AIR PUMPS
Year: 1882

page_text: LETTERS PATENT to Charles Henry Gimingham of the Borough and County
of Newcastle upon Tyne Physicist for an invention of "IMPROVEMENTS IN
AIR PUMPS
"
PROVISIONAL SPECIFICATION left by the said Charles Henry Gimingham
at the Office of the Commissioners of Patents on the 19th May 1882.
CHARLES HENRY GIMINGHAM of the Borough and County of Newcastle upon
Tyne Physicist "IMPROVEMENTS IN AIR PUMPS "
My Invention has for its object to provide an air pump whereby a high vacuum
may be obtained without the circulation of mercury as in the ordinary mercurial
air pumps.
:-
A pump is constructed according to my said Invention as follows:-
An outer glass vessel is provided open at top the exhaust tube or passage leading
from the vessel to be exhausted opened into the bottom of the said vessel and
terminating in a pipe carried up some considerable distance into the said vessel and
having a valve seating at its top-Sliding in the outer vessel is a hollow receiver
or plunger furnished with leather or other washes or rings at its lower end to fit
and slide tightly as a piston in the said outer vessel. The upper end of the hollow
plunger is constructed and formed into a valve seating upon which rests a stopper
or valve which I will call the upper valve. This upper valve is connected by a
flexible connection with another stopper or valve to fit against the valve seating on
the pipe which is carried up inside the outer vessel from the exhaust passage as
aforesaid. The valve I will call the lower valve. It is provided with a spiral
spring which tends to pull it down upon its seat. The hollow plunger is connected
with a slide having a reciprocating motion derived from any couvenient motor
The outer vessel contains mercury which when the hollow plunger is in its highest
position in the said outer vessel rises partly into the said plunger but not to the
level of the opening upon the pipe rising from the exhaust passage. On the
hollow plunger descending the flexible connection between the upper and lower
Paino G21

page_text: valves slackens and the lower valve is brought down upon its seat and closes the
exit of the pipe from the exhaust passage the mercury then rises over the said
valve and forces the air which was in the hollow plunger past the upper valve.
On the return or upward stroke of the hollow plunger air is drawn into the said
plunger past the lower valve and from the pipe leading from the exhaust passage
from the vessel to be exhausted. Thus at each upstroke of the hollow piston air is
drawn from the vessel to be exhausted past the lower valve into the hollow
plunger and on each downstroke of the plunger the air so drawn thereinto is forced
therefrom past the upper valve. The portion of mercury escaping past the upper
valve effectually seals it and the piston rings of the plunger are also luted by a
layer of mercury above them.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Henry Gimingham in the Great Seal Patent Office on
the 18th November 1882.
CHARLES HENRY GIMINGHAM of the Borough and County of Newcastle-upon-
Tyne Physicist "IMPROVEMENTS IN AIR PUMPS"
My Invention has for its object to provide an air pump whereby a high vacuum
may be obtained without the circulation of mercury as in the ordinary mercurial
air pumps According to my said Invention an outer vessel is provided open at top
the exhaust tube or passage leading from the vessel to be exhausted opening into
the bottom of the said vessel and terminating in a pipe carried up some con-
siderable distance into the said vessel and having a valve seating at its top
Sliding in the outer vessel is a hollow receiver or plunger furnished with a leather
or other washer or rings at its lower end to fit and slide tightly as a piston in
the said outer vessel The upper end of the hollow plunger is formed with a
valve seating upon which rests a stopper or valve which I will call the upper
valve This upper valve is connected by a flexible connection with another stopper
or valve to fit against the valve seating on the pipe which is carried up inside
the outer vessel from the exhaust passage as aforesaid. This valve I will call
the lower valve It is provided with a spring which tends to pull it down upon
its seat. The hollow plunger is connected with a slide having a reciprocating
motion derived from any convenient motor The outer vessel contains mercury
which when the hollow plunger is in its highest position in the said outer vessel
rises partly into the said plunger but not to the level of the opening upon the
pipe rising from the exhaust passage and which when the plunger is in its lowest
position rises slightly above the upper valve.
On the upward stroke of the hollow plunger air is drawn from the pipe leading
from the exhaust passage from the vessel to be exhausted into the said plunger
past the lower valve On the hollow plunger descending the flexible connection
between the upper and lower valves slackens and the lower valve is brought down
upon its seat and closes the exit of the pipe from the exhaust passage the mercury
then rises over the said valve and forces the air which was in the hollow plunger
past the upper valve Thus at each up stroke of the hollow piston air is drawn
from the vessel to be exhausted past the lower valve into the hollow plunger and
on each down stroke of the plunger the air so drawn thereinto is forced therefrom
past the upper valve The portion of mercury escaping past the upper valve
effectually seals it and the piston rings of the plunger are also luted by a layer of
mercury above them.
And in Order that my said Invention may be fully understood I shall not [s
proceed more particularly to describe the same and for that purpose shall refer
to the annexed drawing.
The accompanying Drawing represents in sectional elevation an air pump
constructed according to my Invention, the mercury which is used in the said
pump being omitted from the Drawing.
The outer vessel A is opened at top and closed at bottom and into the lower part
thereof opens the exhaust tube or passage a to which is connected the bulb or
other article to be exhausted. The tube b is sealed to the lower part of the
vessel A and extends upwards as shown, It is in communication with the exhaust
tube a but not with the interior of the vessel A The top of the said tube b is
ground into a seating for the lower valve; A hollow receiver or plunger C open at
top and bottom slides as a piston in the vessel A. the said receiver C being provided

page_text: with a packing ring or rings d for giving a tight bearing The upper end of the
said receiver C is provided with a valve seating E upon which rests the upper
valve provided with a Spindle h supported by a guide I having air passages
therethrough The said valve f is provided with a wire g which is attached by
the flexible connection with the valvej which valve j is provided with a spiral
spring which tends to retain the said valve upon its seating The connection kis
of such a length that when the receiver C is at the top of its stroke the valve j is
just lifted from off its seat on the tube b. The receiver C is attached to any
convenient motor by which a reciprocating motion can be imparted to it the bulb
at the top of the said receiver being provided for convenience of connection with
the motor. Mercury is contained in the vessel A and rises into the receiver C the
said mercury not rising to the level of the opening at the top of the tube b when
the receiver C is in its higest position but the said mercury rises just past the
valve when the receiver C is in its lowest position.
When the pump is in action on the upward stroke of the receiver C air is drawn
from the vessel being exhausted up the pipe b and past the valve j which is lifted
from its seating by the pull of the connection /. On the down stroke of the said
receiver the connection k slackens and the valve j is brought down upon its seat
by the spring and closes the exit from the pipe b the mercury rising in the
receiver C past the valve f forcing before it, and from the receiver the air which
was drawn into the said receiver by the previous up stroke as before described.
By repetitions of these alternate movements of the receiver a very complete
The
vacuum may be created in the bulb or other vessel attached to the tube a.
vessels A. and B may be of any convenient material such for example as glass metal
or ebonite.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I wish it to be understood that I do not limit myself to the precise details
herein before described and illustrated in the accompanying drawings as the same
may be varied without departing from the nature of my said Invention but what
I claim as the Invention secured to me by the herein before in part recited Letters
Patent is.
The arrangement and combination of parts constituting the air pump sub-
stantially as herein before described with reference to the accompanying drawing
In witness whereof I the said Charles Henry Gimingham have to this my
Specification set my hand and seal this Eleventh day of November Oue
thousand eight hundred and eighty two.