own PPT

1. By
R.Siva kumar
13765A1008

2. INTRODUCTION
INSTRUMENTS USED IN FURNACE TEMPERATURE
CONTROL
ROLE OF INSTRUMENTATION IN WRM
CONCLUSION

3. INTRODUCTION:
Wire Rod Mill is a continuous 4 strand (4 Lines), 25 stands fully sophisticated high speed rolling mill.
The mill has 4 zone combination type reheating furnace (walking beam cum walking hearth) of
200t/hr capacity for heating the billets received from the billet mill of LMMM to rolling temperature
of 1200°c. The mill produces rounds in 5.5 – 12.7 mm range and rebar’s in 8, 10&12mm range.
During the process of coil forming the head and tail end of the rod can be trimmed,
and the coil can be divided.
1. Type of furnace
2. Products to be heated
3. Temperature conditions
4. Furnace output
5. Fuel
6. Utilities and connected flow
6.1 Mixed gas
6.2 Industrial water for direct cooling
6.3 Industrial water for indirect cooling
6.4 compressed air
7. Instrumentation and control system

5. The main instruments used in WRM walking beam re-
heating furnace
for temperature controls are:
1. THERMOCOUPLES
2. RTDs
3. TRANSMITTERS

6. International designation Conductor material Temp. Range
(°C)
R Pt_ 13% Rh(+)
Pt(-)
0 to 1600
S Pt_ 10% Rh(+)
Pt(-)
0 to 1500
B Pt_ 30% Rh(+)
Pt_ 6% Rh(-)
100 to 1600
Commonly used base metal thermocouple:
K Ni_Cr (+)
Ni_Al(-)
0 to 1100
T Cu(+)
Cu_Ni(-)
-185 to +300
J Fe(+)
Cu_Ni(-)
+20 to +700
E Ni_Cr (+) 0 to 800

7. TWO WIRE CONFIGURATION

8. THREE WIRE CONFIGURATIONS

9. FOUR WIRE CONFIGURATION

10.  As with thermocouples, RTD outputs measuring temperature changes are small. We are at looking at 0.5 ohm/°c.
For an IEC standard device. However the resulting signals are not quite as minute/mA.
 Emerging current with a 100 ohms nominal resistance. RTD sensor yields 5mv. Output for a change of 10°c move
the current up to 5mA and the output is 25mv for 10° change atleast an order of magnitude.
 There are mainly two instruments for determing RTD sensor resistance-measuring bridges (null balance or fixed
bridge direct deflection) in which the supply current can vary and potentiometers. Where the current has to be
known and constant. Both can use AC or DC currents. Although a smooth stable low voltage power supply is the
norm.

11.  The flow transmitter detects the differential pressure/pressure of various fluids, converts it into a current signal of
4 to 20 mA Dc and transmits it.
 All the adjustment functions are incorporated in the amplifier unit for making adjustments easily and exactly.
 The operating principle of the transmitter.
 The input pressure is changed into an electrostatic capacitance in the detecting unit. The change proportional to
the pressure undergoes conditioning and amplification in the amplifier unit, and is then output as a current of 4 to
20 mA Dc.

14. CONCLUSION
The scope can be further extended to study the implementation
of process measurement and control system using PLC. In depth
study of PLC architecture and programming is not within the
scope of this project. The philosophy of this project is
measurement and control of temperature in walking beam
furnace of WRM.