Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to an apparatus for the continuous
measurement oE the temperature of the steel melt of
a converter with the aid o a radiation measuring instrument.
The determination of the temperature is of decisive
irnportance for the control and termination of the blowing
process. Hitherto, the exact temperature in converters
could be determined only with the aid of a thermocouple
which with a lance is briefly dipped into the steel
melt. The thermocouple can be used only for a few seconds
and is destroyed by the high temperature after 10 seconds
at the latest, For each measurement a new thermocouple
must be attached to the lance. Because of this expenditure
the temperature during blasting or blowing is measured
only at relatively long intervals.
A contactless measurement of the temperature with the
aid of a radiation meter is not possible because floating
on the steel melt is a thick layer of slag whose surface
temperature is lower than the temperature of the steel
melt and in addition the measurernent is falsiEied also
by dust and hot waste gases.
German patent 1,066,039 and German patent application
2,138,5~0 disclose a tubular lance or a bore passing
through the wall of the melting crucible to which instead
of a spectrometer in obvious manner a pyrometer measuring
the thermal radiation of the liquid melt could be connected.
Such a device could however only be used for melt crucibles
with calm liquid. It would be completely unsuitable
for use in a converter because by the blasting operation
fluid movements occur in surges due to which the liquid
steel penetrates into the bore of relatively large diameter
and clogs therein when solidified. This can also not
be prevented by increasing the flow rate of the inert
gas because the gas then cools down the region of the
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mouth oE tile bore to an even greater extent and there :is
an even greater tendency Eor solidified melt to clog therein.
In addi-tion, the cooling gas would also cool -the mel-t directly
in front of the bore and -this would falsify the measurement.
The problem underlying the invention is to design a passage
projecting into the melt with built-in radiation measuring
instrument in such a manner that this apparatus can also be
used in a blasting converter and no solidifying melt settles
at the mouth of the passage and the cooling effect of the
inert gas on the melt does not lead to any measurement errors.
The invention relates to apparatus for measuring the temper-
ature in a converter with a radiation measuring instrument
which is connected to one end of a rectilinearly extending
passage for receiving the radiation incident through the
passage whilst the other end of the passage opens into the
liquid steel melt and at the latter end an inert or reaction-
poor gas or gas mixt~re flows under excess pressure into the
steel melt. The passage has at least at the end opening
into the steel melt a cross-sectional area which is not
greater than 1 cm and the discharge velocity of the gas or
gas mixture is a flow of at least 10 grams per minute with
respect to a cross-sectional area of 1 mm2. ~ thermal radi-
ation measuring instrument is connected to the passage as
the radiation measuring instrument. When operating the appar-
atus for temperature measurement, it is calibrated at rela-
tively long time intervals by comparison with a conventional
immersion -temperature measurement.
It has been surprisingly found that small nozzles with high
flow rate of the cooling gas are suitable for the measure-
ment. Presumably, turbulence of the liquid directly in front
of the nozzle ensures that the particles struck or cooled
by the gas are largely surrounded by uncooled particles and
consequently the radiation inciden-t into the passage depends
mainly on the uncooled particles. Due to the turbulence in
fron-t of -the nozzle the solidifying parts of the steel melt
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cannot settle because -they are torn away from the edye oE
the nozzle and blown back in-to -the steel melt.
The temperature can be determined wi-th a single measuring
device at various points of the melt bath and a-t various
heights of the mel-t bath if the apparatus is attached -to a
lance which is introduceable from above into the melt bath
and contains a passage for the radiation to be measured.
Advantageously, the passage for the measurement leads through
the bottom of a converter into which "agitating gas nozzles"
are built. The passage for the measurement may itself act
as "agitating gas nozzle". It may however also be operated
with a lower gas speed than the "agitating gas nozzles" if
in its vicinity agitating gas nozzles are installed which
ensure adequate agitation of the melt in the region of the
passage to be measured as well.
Because of the very small diameter and the long length of
the passage it is difficult to receive adequa-te radiation
from the melt at the pyrometer. For this reason, advan-
tageously the radiation is received through a lens which is
installed approximately one third of the thickness of the
converter wall from the outer surface in the passage, some-
what widened a-t this point, and conducts the radiation via
an optical waveguide to the pyrometer which is disposed out-
side the converter. The diameter of the optical lens and
the optical waveguide should only be of such magnitude that
the remaining free flow area is greater or equal to the
cross-sectional area of the -thinner por-tion of the passage.
The single figure is an example of embodiment of the inven-
tion showing only the lower portion of a converter,
Referring now to the figure only the bottom 11 and lower
portion of the side wall 12 oE the converter are shown~
Indicated in the bottom 11 are the agitating gas nozzles 13,
14 and 15 which receive the inert gas from the manifold tube
16. The agitating gas nozzIe 14 serves at the same time as
passage for passage of radiation to the pyrometer 17. The
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radiation is lncident ~irstly on the lens 18 and Erorn
there radiated into the op-tical waveguide 19 whlch
conduc-ts the radia-tion to the pyrometer 17. The opti-
cal waveguide 19 leaves the manifold tube sub~ected to
gas pressure at a bore which is sealed by a seal 20.
In a somewhat poorer embodiment the radiation measure-
ment would still be possible if the lens 18 and the
optical waveguide 19 were omitted instead of the seal 20
a transparent window is provided and the pyrometer 17
installed directly beneath the window.
The passage 14 with the radiation measuring instrument
may be incorporated in another embodiment also in a
lance adapted to be dipped from above into the steel
melt.
