Improvements in Means for Measuring the Density of Gases, and like purposes.
Year: 1892

page_text: Date of Application, 15th July, 1892
Complete Specification Left, 15th Apr., 1893-Accepted, 10th June, 1893
PROVISIONAL SPECIFICATION.
Improvements in Means for Measuring the Density of Gases,
and like purposes.
I, REGINALD HADDAN, of the firm of Herbert & Co. 18 Buckingham Street
Strand W.C. London, Patent Agent do hereby declare the nature of this invention
a communication to me from abroad by Walther Dürr, and Alphons Custo:lis, both
of 85 Kaulbachstrasse Munich in the Empire of Germany Engineers, to be as
follows:-
This invention relates to that class of apparatus in which a balance beam carries
at one end a closed globe and at the other end a counterweight, there being an
indicator and scale provided for reading the density of the gas surrounding the
apparatus aforesaid indicated by the inclination given to the beam by reason of
the difference in density between the said gas and the air or gas within the closed
globe which caused the latter to rise or sink accordingly.
Such apparatus is useful especially for ascertaining the amount of carbonic acid
gas in smoke and gaseous products passing through a closed chamber provided
with a glass window, within which such apparatus is erected.
The object of the present invention is to provide means for automatically
correcting the variations in reading produced by variations of pressure or
temperature, in other words to automatically reduce the reading to that for a
standard pressure and temperature.
It has been sought to effect this by means of a shifting body of liquid such as
mercury or sulphuric acid which seals a body of air in a small cavity; this body
of air being subject to the same effect of compression or expansion corresponding
to the barometric pressure and temperature existing at the time of the observation,
causes the body of liquid to shift to or from the vertical plane of the fulcrum of
the balance and consequently alters its centre of gravity and moment with regard
to the fulcrum. It is however found that with such compensator that apparatus
cannot be constructed with sufficient delicacy owing to the large amount of
movement which must be given to the liquid to produce its full measure of
compensation.
According to this invention the tube which contains the body of liquid is so
arranged beneath the fulcrum and in the line of the balance that its centre of
gravity in the normal condition occupies as nearly as possible a position in the
vertical plane of the fulcrum of the balance. It is then clear that a very small
movement of the liquid to the one or other side is sufficient to produce a moment
of great compensating value. The air cavity may be made rather larger than
usual.
For regulation there is provided a horizontal arm under the balance beam, screw
threaded to receive a screw threaded weight; the whole system is also rendered
very sensitive by arranging on the balance beam over the fulcrum a perpendicular
screw threaded post on which is a screw threaded weight.
Dated this 15th day of July 1892.
HERBERT & Co.,
Agents to Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Means for Measuring the Density of Gases,
and like purposes.
I REGINALD HADDAN, of the firm of Herbert & Co., of 18, Buckingham
Street, Straud, London, W.C., Patent Agent, do hereby declare the nature of this
invention, a communication from abroad by Walther Dürr and Alphons
Custodis, both of 85, Kaulbachstrasse, Munich in the Empire of Germany,
Engineers, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to that class of apparatus in which a balance beam carries
at one end a closed globe and at the other end a counterweight, there being an
indicator and scale provided for reading the density of the gas surrounding the
apparatus aforesaid indicated by the inclination given to the beam by reason of the
difference in density between the said gas and the air or gas within the closed globe,
which causes the latter to rise or sink accordingly.
、
Such apparatus is useful especially for ascertaining the amount of carbonic acid
gas in smoke and gascous products passing through a closed chamber provided
with a glass window, within which such apparatus is erected.
The object of the present invention is to provide means for automatically
correcting the variations in reading produced by variations of pressure or
temperature in other words to automatically reduce the reading to that for standard
pressure and temperature.
It has been sought to effect this by means of a shifting body of liquid such as
mercury or sulphuric acid which seals a body of air in a small cavity, this body of
air being subject to the same effect of compression or expansion corresponding to
the barometric pressure and temperature existing at the time of the observation,
causes the body of liquid to shift to or from the vertical plane of the fulcrum of
the balance, and consequently alters its centre of gravity and moment with regard
to the fulcrum. It is however found that with such compensator that apparatus
cannot be constructed with sufficient delicacy owing to the large amount of
movement which must be given to the liquid to produce its full measure of
compensation.
According to this invention the tube which contains the body of liquid is so
arranged beneath the fulcrum and in the line of the balance, that its centre of
gravity in the normal condition occupies as nearly as possible a position in the
vertical plane of the fulcrum of the balance. It is then clear that a very small
movement of the liquid to the one or other side is sufficient to produce a moment
of great compensating value. The air cavity may be made rather larger than
usual.
For regulating there is provided a horizontal arm under the balance beam, screw
threaded to receive a screw threaded weight; the whole system is also rendered
very sensitive by arranging on the balance beam, over the fulcrum, a perpendicular
screw threaded post on which is a screw threaded weight.
An improved apparatus on this principle is shown in the annexed drawing. The
beam B carries on its one end a light hollow globe of glass G, the weight of this
globe being compensated by a counterweight attached to the other end of the
balance beam.
The whole is placed in a corresponding large case A hermetically closed and
provided with a glass window, the gases to be measured being passed into and
through this case; the compensator consists of a U shaped tube C open at one
end and closed on the other end a and partially filled with a liquid (such as
mercury or sulphuric acid) in such a manner that a certain quantity of dry air is
enclosed. As soon as the temperature or the barometric pressure or both at same

page_text: time change, the volume of this enclosed air changes accordingly, and the liquid is
moved and consequently the centre of gravity of the system is shifted.
This shifting of the centre of gravity causes the hand on the other arm of the
balance to alter its position on the scale.
The compensator C is fixed on the small balance beam in such a way that the
free arm of the glass tube clies beyond the vertical plane of the fulcrum of
the balance beam so that the centre of gravity of the mercury column, when in
normal condition, lies approximately in the vertical line drawn through the fulcrum
of the beam. W and E are the adjustable weights for regulating the balance.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is,
1. An improved apparatus for measuring the density of gases etc. having a
compensator for the temperature and pressure substantially as described, so
arranged that under normal conditions the centre of gravity of the movable body
of liquid within the compensator, rests approximately in the vertical plane of the
fulcrum of the balance beam.
2. In apparatus for measuring the density of gases substantially as herein
described, the combination with the balance beam of the movable weights W and E
either or both for the purpose of regulation of the accuracy and delicacy of the
instrument arranged substantially as set forth.
11
CA
11000
R. HADDAN,
Herbert & Co.,
18, Buckingham Street, Strand, London, W.C.
R. HADDAN,
Herbert & Co.,
18, Buckingham Street, Strand, London, W.C.