An Improved Device for Augmenting or Reducing as Required. the Quantities of Mercury or Fluid in the Capillary Tubes of Thermometers.
Year: 1896

page_text: Date of Application, 25th Mar., 1896-Accepted, 25th July, 1896
COMPLETE SPECIFICATION.
An Improved Device for Augmenting or Reducing as Required.
the Quantities of Mercury or Fluid in the Capillary Tubes of
Thermometers.
We, LEO EHMANN and HERMANN OBERMAYER, both of 1 Karnthnerstrasse, 59,.
Vienna in the Austrian Empire Manufacturers 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 object of this invention is to provide an arrangement or device adapted to
be attached to the well known Beckmann thermometers, for enabling the quantity
of mercury, or of fluid, as the case may be (which must vary according to the
limits within which the temperature in any given space or room has to be.
maintained) to be, simply by "back suction" and by inclining the instrument,
conveyed into the thermometer capillary tube in a ready and reliable manner from
a receptacle or reservoir, wherein a supply of such mercury or fluid is stored.
In the accompanying drawings, for the purpose of illustrating the invention, the
improved arrangement is shewn in connection with two forms of heat indicating
and regulating instruments. The arrangement consists of a tube S, which may
vary in length according to requirements and which, forms a continuation or
extension of the capillary tube k and reaches into the storage receptacle E and
terminates in a perforated point.
Owing to the fact that the pointed perforated end of this tube when the
thermometer is inclined is immersed in the mercury or in the liquid in the
receptacle E it is only necessary to incline the thermometer (in the direction of
the arrow I) to cause, simply by "backward" or inverted suction, precisely the
requisite quantity of such mercury or fluid, to enter the capillary tube; the
pointed extremity of the tube S admitting of the capillary mercury or fluid
filament being broken precisely at the desired moment.
In the modification shewn in Figure 1, the thermometer consists of a chamber G,
say of glass, the U shaped capillary tube k, the storage reservoir E and the
pointed tube S.
At convenient points of the apparatus, as at 1, 2, and 3-platinum electrical
contacts are fused or welded into the material of the tube and these are connected
to an external source of electricity. The apparatus is filled with fluid suitable for
thermometrical purposes and being a bad conductor of electricity; the only parts
not so filled being those which are marked in black in the drawing and a small
space left free for the development of gas in the reservoir or chamber E.
The portions marked in black are filled with mercury.
By heating the chamber G any required quantity of either mercury or fluid
(which must, of course, be confined within the limits set by the dimensions of the
instrument) may be caused to pass from the tube k into the said chamber E; and
then by cooling the instrument, or allowing it to cool, to its previous temperature
whilst in the upright position the same quantity of the mercury or fluid as the
case may be, forced into the chamber E, and into which the point of the tube
(extension S) is dipped, will be sucked or drawn back into the tube k. By tilting
the apparatus however in the direction of the arrow I while cooling, any desired
amount of mercury in place of fluid (Fig. 1) or of the fluid filled in over the
mercury, in place of mercury (Fig. 2) may be drawn into the capillary tube. In

page_text: order to cut off the supply of mercury or fluid as soon as the requisite quantity
of either (found by experiment, to correspond to the difference of temperature for
the time being) has passed into the capillary tube, it is only necessary to turn the
instrument back to its normal upright position.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In thermometers for controlling or regulating temperature, the provision of a
pointed perforated tube, such as S, forming an extension of the capillary tube, and
opening into a storage-chamber or reservoir, so that mercury or other fluid can be
supplied to the capillary tube as required, by simply tilting or inclining the
instrument, and then breaking off the capillary current of mercury or other fluid
precisely at the desired moment, at the point of the tube S, by turning the
instrument back to the normal position.
Dated this 25th day of March 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.