IMPROVEMENTS IN EXHAUSTING miותתו
Year: 1882

page_text: LETTERS PATENT to Alexander Ritchie Leask of Holborn Viaduct in the
county of Middlesex for an invention of " IMPROVEMENTS IN EXHAUSTING
miותתו
PROVISIONAL SPECIFICATION left by the said Alexander Ritchie Leask
at the Office of the Commissioners of Patents on the 8th June 1882.
ALEXANDER RITCHIE LEASK of Holborn Viaduct in the County of Middlesex,
"IMPROVEMENTS IN EXHAUSTING APPARATUS
"
This invention may be described as a mercurial air-pump, and while it is
applicable to most purposes for which air-pumps are used, it has special reference
to exhausting the bulbs of incandescent electric lamps. The main features of this
invention are as follows
"
I erect a suitable framework by preference of wood to which I attach the
pumps" These consist of a vertical tube,-preferably of glass on account of the
mercury-having upon its upper end a large bulb connected by a neck with a
smaller bulb above it; a ground stopper fits the neck and closes the passage
between the two. Out of the vertical tube branches a smaller tube horizontally
the end of which is bent up and terminates at or about the level of the centre of
the smaller bulb of the pump. A sliding seal tube of ordinary construction is
fitted to the end of this branch and also to the lamp or vessel tube and elsewhere
if required. A long syphon of glass tube is formed and connected to the branch
at one end and to a cross tube at the other which cross tube carries three or more
branches upon which the lamps or other vessels to be exhausted are placed or
with which they are connected. The number of branches is regulated by the
size of the vessels to be exhausted, the smaller the size the greater the number
and vice versa.
A suitable glass bottle with a cylindrial neck and a sling to hang it by and the
bottom drawn out into a tapering tube is connected by a flexible tube from the
bottom with the lower end of the pump. Upon rails of the framework are fitted
brackets for supporting the bottle, the pump, the lamp tube and lamp or other
vessel which are all so arranged that the bottle pump &c can be promptly removed
[Prins G11

page_text: when required. Within certain of the rails are grooves or channels within which
are the positive and negative wires from a dynamo machine when an electric
current is required in the process of exhaustion and from these wires I run branch
wires for each lamp tube. Upon a rod at or near the top of the frame work are
hung suitable hooks for each bottle to hang from and so placed that when a
bottle is hung up its bottom is upon a level with the centre of small bulb of
pump.
The action is as follows: To charge the pump the bottle is hung up and mercury
poured into the small bulb of the pump until it reaches the middle of said small
bulb The bottle is now lowered and the mercury recedes from the pump bulb and
enters the bottle, leaving a more or less perfect vacuum in the pump bulb and as
it drops in the vertical tube lower than the horizontal branch tube which connects
with the syphon tube and the lamps or vessels to be exhausted, the air contained
therein rushes into the pump and upon the bottle being raised and the rising
mercury closing the horizontal branch tube, the air in the pump bulb is compressed
and allowed to escape by lifting for a moment the stopper in the neck of the pump
bulb;
this operation is repeated as often as necessary-I do not limit myself to
the number of pumps which may be used upon one framework and they may be
placed upon one or more sides thereof. I reserve to myself also the right to make
such reasonable alterations in the construction of this apparatus as may be found
necessary in practice. It will be observed that each pump is capable of exhausting
a considerable number of lamps &c according to circumstances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Ritchie Leask in the Great Seal Patent Office on the
8th December 1882.
"
ALEXANDER. RITCHIE. LEASK, of Holborn Viaduct in the county of Middlesex
IMPROVEMENTS IN EXHAUSTING APPARATUS".
This invention may be described as a mercurial air-pump and while it is
applicable to most purposes for which air-pumps are used it has special reference
to exhausting the bulbs of incandescent electric lamps. The main features of this
invention are as follows:-
"
I erect a suitable framework by preference of wood to which I attach the
"
pumps' These consist of a vertical tube preferably of glass on account of the
mercury-having upon its upper end a large bulb connected by a neck with a
smaller bulb above it; a ground stopper fits the neck and closes the passage
between the two. Out of the vertical tube branches a smaller tube horizontally
the end of which is bent up and terminates at or about the level of the centre of
the smaller bulb of the pump. A sliding seal tube of ordinary construction is fitted
to the end of this branch and also to the lamp or vessel tube and elsewhere if
required. A long syphon of glass tube is formed and connected to the branch at
one end and to a cross tube at the other which cross tube carries three or more
branches upon which the lamps or other vessels to be exhausted are placed or
with which they are connected. The number of branches is regulated by the size
of the vessels to be exhausted the smaller the size the greater the number and
vice versa.
A suitable glass bottle with a cylindrical neck and a sling to hang it by
and the botton drawn out into a tapering tube is connected by a flexible
tube from the bottom with the lower end of the pump. Upon rails of, the
framework are fitted brackets for supporting the bottle the pump, the lamp
tube and lamp or other vessels which are all so arranged that the bottle
pump &c can be promptly removed when required. Within certain of the
rails are grooves or chambers within which are the positive and negative wires
from a dynamo machine when an electric current is required in the process of
exhaustion and from these wires I run branch wires for each lamp tube. Upon a
rod at or near the top of the frame work are hung suitable hooks for each bottle
to hang from. I do not limit myself to the number of pumps which may be used
upon one framework and they may be placed upon one or more sides thereof. I
reserve to myself also the right to make such reasonable alterations in the con-
struction of this apparatus as may be found necessary in practice. It will be
observed that each pump is capable of exhausting a considerable number of
lamps & according to circumstances.
In the accompanying drawings in which like letters of reference represent like
parts Figure 1 is a front elevation of the frame, two pumps being shewn in place:
Figure 2 is a section on line Z Z Figure 1 and shews an end view of the apparatus
with pumps on both sides; Figure 3 is a like view to Figure 2 but shews lamps
instead of pumps; Figure 4 is an adjustable spring clip for holding the lamps;
Figure 5 is a clip for fastening the tubes to the frame.
A A are the upright ends of stout timber securely braced at top and bottom and
other places by strong cross bars B-B and having feet C C to make the whole
stand firmly; or the uprights can be planted firmly in the ground or otherwise
secured. Some of these cross bars B are made hollow as shewn in Figure 2 and
these serve to enclose the wires from and to the dynamo machine. D D are the

page_text: mercury bottles connected by flexible tubes D¹ with the pumps E which are
supported upon brackets F as shewn. From the necks of the pumps E branch
pipes E extend laterally and then rise vertically to about the centre of the smaller
bulb E2 of the pumps where they are connected by ordinary mercury seals to the
shorter limbs of long syphon tubes G the other ends of which connect with cross
tubes G¹ which cross tubes carry vertical branches G³ to which are attached by
mercury seals the lamps G³ which are to be exhausted-ground glass stoppers E³
fit the necks of the pumps between the bulbs E and E².
The bottles D are hung in slings D2 for convenience in lifting them about. From
rails D³ upon the frame depend hooks D' upon which the slings are hung when the
bottles required to be held up. In Figure 1 the bottle on the right hand side is
shown hung up while that at the left hand side is shewn resting on its bracket at
the bottom of the frame. Referring to Figures and 3 it will be seen that the
whole arrangement is duplicated upon the other side of the frame and it becomes
evident that a very great economy of space is effected by this peculiar construction
of frame & The action of the pumps is as follows:-
To charge the pump the bottle D is hung up and the stopper Es haying been
removed mercury is poured into the small bulb E2 of the pump until it
reaches the middle of the said small bulb the stopper Es is now inserted and the
bottle D. lowered and the mercury recedes from pump bulb into the bottle leaving
a more or less perfect vacuum in the bulb E and as it falls below the level of the
branch pipe E¹ which connects with the tube G and lamps to be exhausted a
portion of the air contained therein rushes to fill the vacuum in the bulb E, and
upon the bottle being raised again and the rising mercury closing the branch E'
the air in the bulb E is compressed and allowed to escape by lifting for a moment
the stopper Es. This operation is repeated as often as necessary
As already stated the wires from the dynamo machine are placed in the spaces in
the hollow cross bars B¹ and branch wires from these connect with the lamp terminals
as will be well understood. In Figure 1 the lower bar B¹ carries the leading wire
from the dynamo a switch B2 being provided for making or breaking contact as
required B³ is the main wire from the dynamo. The return wire is placed in the
upper cross bar B' and a switch B4 is provided for it also; B5 is the main return
wire. Be are the connecting leading wires to the lamps and B7 the return
connecting wires.
When made of Glass the tubes Ģ often break & it is therefore important to have
them so connected to the frame that they can be detached and replaced without
waste of time. This I accomplish by means of the clip shewn in Figure 5 the
slits in which fit over screws or projections upon the frame and which can be
removed in a moment if necessary.
It is customary to employ glass only for the tubes G as there is no danger of the
mercury spoiling glass but glass is very liable to break and I find that iron such as
ordinary gas piping will do just as well and not break. The connections can be
conveniently made by couplings in the ordinary manner for gas fittings, and the
pipes can be bent or elbows used for the corners. I prefer not to carry the shorter
limb of the iron pipe down beyond the nercurial seal x Figure 1 as then the height
of the mercury in the pipes can be traced as far as is necessary.
It is usual in this form of pump to form the bulb E with a long glass stem
extending to about the bottom of the frame; it is very likely to get broken and I
find it better to dispense with the long stem and connect the flexible tube close
below the bulb. I thereby save both piping and mercury and make the pump
stronger more compact and less expensive
For holding the lamps whilst being exhausted various temporary and inefficient
devices are adopted such as a piece of twisted wire; but this is clumsy, not
adjustable and inconvenient in many ways for instance the height of lamps varies
considerably and the wire will be too long for one or too short for another and is
liable to break the lamp by being twisted up too tight. Now I get rid of these
difficulties by employing the adjustable spring clip shewn in Figure 4. It consists

page_text: as will be seen of a divided clip of springy wire or the like held together by the
movable sleeve H so that the grip may be adjusted and immediately released if
required. The set-screw I is for fixing it at the proper height upon the vertical
rod K (Figure 3) The form of this clip may be modified for instance a plain
double spring clip consisting of two springs fastened together at or near the centre
could be used instead. The tube G₁ is made of larger diameter than tube G and
the branches G2 to prevent blocking in case any mercury should get into it and to
facilitate the withdrawal of the air from the lamps. By this arrangement of tubes
a considerable number of lamps may be exhausted by a single pump; four are
shown in the drawing and that is a convenient number, but a larger or smaller
number can be treated at one time. The object in carrying the syphon tube G up
so high is to prevent the mercury from running past the bend at the top which it
is apt to do if the pipe is short; also when glass is employed for this tube the extra
length reduces the likelihood of its being broken.
A block of wood L hollowed out to receive the pump E rests upon the brackets F
and holds the pump while it can be readily and promptly removed when needed.
The slings D² consist of side strips of metal and a wooden block hollowed to receive
the bottle and a cross bar or handle to join the strips at the top. The form is
clearly shown in figures 1 and 2.
Having now described my invention and the method of performing the same
I wish it to be understood that what I claim and desire to protect under the
herein before in part recited letters patent is ;-.
First. In a mercurial exhausting apparatus the herein described construction of
framing and attachments substantially as set forth and illustrated.
Second. The herein described construction of pumps E in which the flexible
tube D¹ is attached without the intervention of a long stem substantially as and
for the purposes set forth
Third. The arrangement of the wires B³ and B° and switch B leading the current
to the lamp and the wires B7 and B5 and switch B' leading from the lamp
substantially as and for the purposes set forth and shewn.
Fourth. The tubes G₁ of larger diameter than tubes G or G³ whereby an open
passage may be secured even though said pipe be partly choked.
Fifth. The bottle slings.D³ substantially as set forth.
Sixth. In a mercurial exhausting apparatus the employment of the iron
tubes G G¹ and G2 whereby the risk of breakage is greatly lessened substantially as
set forth.
Seventh. In combination with a mercurial exhausting apparatus the employment
of an adjustable spring clip for holding the lamps whilst being exhausted and
from which they can be immediately released substantially as and for the purposes
set forth and shewn.
Eighth. In combination with a mercurial exhausting apparatus the employment
of the detachable clip substantially as and for the purposes set forth and illustrated
in Figure 5 of the accompanying drawings
In witness whereof I the said Alexander Ritchie Leask have hereunto set
my hand and seal this Seventh day of December in the year of our Lord
one thousand eight hundred and eighty two.
A. R. LEASK (L.S.)