Field of the Invention:
The present invention relates to a device for monitoring the flame intensity inside
the blast furnace through tuyeres.
Background and prior art:
Flame inside the blast furnace around raceway zone is visible through flame
peephole of tuyeres. Operators can physically inspect the flame intensity through
peephole of tuyeres and conclude regarding hanging in the furnace, scab in the
tuyer zone and burden distribution inside the furnace.
The number of tuyeres can vary from furnace to furnace. A typical furnace may
have 22 tuyeres. In the existing system the operators need to monitor physically
all the tuyeres every half an hour resulting in delay in detecting a fault.
The main object of the present invention therefore, is to detect instantaneously a
fault in a particular tuyere.
This object is achieved in the present invention by providing a device for
monitoring the flame intensity levels of all the tuyeres and to display these
intensity levels on a monitor of a central Human Machine Interface HMI. This
HMI can be provided at the central room for the operators to monitor the
tuyeres.
Korean patent publication KR 1003 76525B discloses apparatus and method for
monitoring Wast furnace raceway. It discloses acquiring of luminance data for
race way of blast furnace, but the present invention has the uridermentioned
distinguishing features over this publication.

1. The present invention does not disclose CCD, which makes it simpler
and cost effective.
2. The present invention uses special lens attached to the tuyer. The tens
has to be high temperature resistant because of the high temperature
of the area where it is mounted. This is an advantageous
distinguishing feature, as it makes the detection much simpler and
cheaper. KR 1003 765256 employs entirety different technique.
3. The above publication discloses use of sound wave flow meter, which
is not used in the present invention.
4. As the present invention does not deploy CCD, the necessity of
obtaining luminance gradient for pixel, a complicated step, is avoided.
Japanese patent publication JP 2000 086263 discloses a device for drawing an optical fiber pre-form. The disclosed invention relates to a totally different field. Although detection of change in luminous intensity is disclosed, the photo detector disclosed is totally different from that of the present invention. The response for wavelength range is entirely different. Moreover, no direction of detection is necessary in the present invention
A fiber optic light guide is fitted at one end to a tens assembly provided on a tuyere of a blast furnace. The other end of the fiber optic light guide can be connected to a photo detector. The

photo detector comprises a photo detector amplifier, a voltage to milli amp converter and a DC power supply. This photo/detector can output an electrical signal representing the intensity of the flame and hence the temperaure of the hot Metal inside the blast furnace. The output signal comprising 4—20 A can be connected to a programmable logic controllewr of a Hfll system and the monitor can provide the intensity level of the flame.
Thus the present invention provides a device for monitoring the flame intensity inside a blast furnace through tuyeres, comprising a lens assembly fitted to the tuyere of the blast furnace, a fiber optic ligh guide, one end of which is attached to said lens assembly, a photo detector connected to the other end of said fiber optic light guide, for outputting an electrical signal to a programmable logic controller of a HHI system for displaying the intensity level of the flame inside said blast furnace.
If the intensity level falls below certain predetermined level the HWI system can generate an alarm and a fault can be detected for a particular tuyere instantaneously.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows the arrangement of the tuyere of a blast furnace.

WE CLAIM:
1. A device for Monitoring the flame intensity inside a blast
furnace through tuyeres, comprising :
- a lens assembly fitted to the tuyere of the blast furnace;
- a fiber optic light guide, one end of which is attached to
said lens assembly;
- a photo detector connected to the other end of said fiber
optic light guide, for outputting an electrical signal to a
programmable logic controller of a MMI system for displaying
the intensity level of the flame inside said blast furnace.
2. The device as claimed in claim 1, wherein said photo
detector is a In6aAs IR detector.
3. The device as claimed in claims 1 or 2, wherein said
photo detector comprises a photo detector amplifier, a voltage-
mi Hi amp converter and a DC power supply.
4. The device as claimed in the preceding claims, wherein
said HMI system is configured to generate an alarm indicating a
fault when the flame intensity falls below a predetermined level.
5. A device for monitoring the flame intensity inside a
blast furnace through tuyeres substantially as herein described
and illustrated in the figures of the accompanying drawings.

A device for monitoring the flame intensity inside a blast furnace through tuyeres, comprising a lens assembly fitted to the tuyere of the blast furnace; a fiber optic light guide, one end of which is attached to said lens assembly; a photo detector connected to the other end of said fiber optic light guide, for outputting an electrical signal to a programmable logic controller of a HMI system for displaying the intensity level of the flame inside said blast furnace.