TEMPERATURE MEASUREMENT AND THERMAL IMAGING
OF THE CASING OF A ROTARY KILN
V. A. Zakharenko
and V. A. Nikonenko
Translated from Ogneupory i Tekhnicheskaya Keramika, No. 4, pp. 43 – 45, April, 2002.
Since the late 1970s, first scanning radiation pyrometers
[1, 2] and then thermal imaging systems have gained accep
tance in the cement industry for temperature control of the
walls of rotary kilns .
In the scan technique used, the sector of view spans
lengthwise a section of the casing of a rotary kiln (Fig. 1) to
record the infrared radiation emitted by the heated casing
Since the scan speed is much higher than the kiln rota-
tion speed, it is assumed that the line of temperature monitor-
ing on the casing wall remains parallel to the kiln axis. This
makes it possible to form a line-to-line temperature image of
a selected portion in the sector of view synchronized with the
kiln rotation. Here the size of the image frame is determined
by the circumferential length of the kiln cylinder.
Since 2000, a system for thermal imaging control of the
casing of the STK-1-type rotary kiln has been commercially
available from the Étalon state enterprise at the Gosstandart
(State Committee for Standardization) of Russia (Omsk) spe
cializing in the production of temperature measuring instru
mentation for industrial and verification applications .
The system in question is a firmware facility that in
cludes one or two primary sensing devices, an IBM-compati
ble computer, a software for processing and visualizing the
temperature field of the kiln casing, and a communication
Using a primary sensor, a sector of view with a visual an
gle of about 100° is scanned lengthwise in such a manner
that the infrared radiation emitted by the kiln casing can be
recorded within 250 msec (Fig. 1).
A schematic diagram of the primary device is shown in
Fig. 2. It consists of an electromechanical scanner (EMS)
unit and its components 1, 2, 3, 4, and 5; a radiation detector
(RD) printed circuit board and its components 6, 7, and 8;a
digital processing unit (DPU) circuit board and its circuit
components 9, 10, 11, 12, 13, and 14; a two-wire communi
cation line (CL); a communication channel adaptor (CCA),
and a power supply (PS). The radiant flux F emitted by the
casing wall (proportional, in conformance with the Stefan –
Boltzmann law, to the wall temperature) falls onto mirror 1
of the EMS unit that is rotated at the speed w = 4 rev/sec by
a dc motor 5.
The rotating mirror provides scanning of the radiant flux
along the length of the kiln casing. The radiant flux reflected
from the mirror is directed, through a stopper, to the radiation
detector RD integrated into electrical circuit 6. The EMS unit
includes an optical sensor 2 for mirror speed control and an
electronic circuit 4 for mirror speed stabilization. Optical
sensor 3 serves to detect signals that indicate the position of
the mirror with respect to the sector of view; electronic cir
cuit 8 of the RD unit provides for the synchronized operation
of RD unit keys and the data reception/transmission clock
ing in the DPU unit. The RD circuit 7 serves to control zero
stability and detection sensitivity.
An analog signal from the radiation detector is fed into a
ten-bit analog-to-digital converter (ADC) 9; ADC parallel-
Refractories and Industrial Ceramics Vol. 43, Nos.3–4, 2002
1083-4877/02/0304-0154$27.00 © 2002 Plenum Publishing Corporation
Omsk State Technical University, Omsk, Russia; Étalon Omsk
Experimental Plant, Omsk, Russia.
line and ada
Fig. 1. Schematic illustration of a technique for temperature control
of the casing wall of a rotary kiln.