2. PRESENTATION OVERVIEW
TYPE OF WEIGHING SYSTEM
CAMPARESION OF WEIGHING SYSTEM
COAL FEEDER PRINCIPLE
COAL FLOW CALCULATION
COAL FEEDER INSTRUMENT
COAL FEEDER PERMISIVE
COAL FEEDER TRIPPING INTERLOCK
COAL FEEDER LOGIC VIEW
COAL FEEDER SYSTEM OVERVIEW
3. TYPE OF WEIGHING SYSTEM
• VOLUMETRIC
• GRAVIMETRIC
VOLUMETRIC SYSTEM
IN VOLUMETRIC SYSTEM ROTORY BUCKET ARE USED
IN THIS SYSTEM BULK DENSITY IS REQUIRE FOR THE
WEIGHT CACULATION
GRAVIMETRIC SYSTEM
IN GRAVIMETRIC SYSTEM BALANCE BELT SYSTEM IS
USED
IN THIS SYETEM BULK DENSITY NOT REQUIRE BECAUSE
WE GATTING DIRECT WEIGHT OF ANY MATERIAL
4. CAMPARESION OF WEIGHING SYSTEM
VOLUMETRIC SYSTEM
VOLUMETRIC SYSTEM USING FIXED VALUME
TYPE BUCKET SO DUE TO SIZE VARIATION IS
GIVING MORE ERROR.
6. GARVIMETRIC SYSTEM
BECAUSE OF THE HETEROGENEITY OF COAL, GRAVIMETRIC
FEED SYSTEMS USED OVER VOLUMETRIC SYSTEM.
THE VOLUME FLOW MEASUREMENT WILL BE IN ERROR BY THE
VARIATION IN THE BOTH DENSITY AND HEATING VALUE,
WHEREAS THE WEIGHT FLOW SIGNAL WILL BE IN ERROR ONLY
TO THE EXTENT OF VARIATION IN THE HEATING VALUE.
8. The gravimetric feeder weighs material on a length of belt
between two fixed rollers using a weighing roller.
Belt speed is determined by a tachometer attached to the
motor shaft. A microprocessor multiplies the speed and weight
signal to arrive at the feeder output.
The microprocessor matches the feeder output to the
demanded output by adjusting the feeder motor speed.
9.
10. Load Cell
Load Cell Excitation =10V
Load Cell Sensitivity =2mV/V
Load Cell CAPACITY=100KG
Capacity
Load Cell Weight Constant =
Sensitivity X Excitation
100
=
2 x 10
Load Cell Weight Constant = 5 Kg/mV
HOW TO CALCULATE CELL CONSTANT
11. Load cell mV to KG conversion
No Load mV
No Load Cell 1 mV = 3.35mV
No Load Cell 2 mV = 3.30mV
With Load mV
Load Cell 1 mV = 5.80mV
Load Cell 2 mV = 5.50mV
Load on load cell 1mV = Load Cell 1 mV - No Load Cell 1 mV
= 5.80 - 3.35 = 2.45 mV
Load on load cell 2mV =Load Cell 2 mV - No Load Cell 2 mV
= 5.50 - 3.30 = 2.20 mV
Total mV = Load on load cell 1mV + Load on load cell 2mV
= 2.45 + 2.20 = 4.65mV
Weight in KG = Total mV x Load Cell Weight Constant
= 4.65mV x 5 Kg/mV
Weight in KG = 23.25 Kg
12. ADVANTAGE OF GRAVIMETRIC COAL FEEDER SYSTEM
Fuel Savings through Improved Boiler Efficiency
Improved Combustion Efficiency/LOI
Improved Pressure and Superheat Control
Less Slagging and Plug gage
Less NOx through Better Control of Excess Air
Less Corrosion
Stability and Improved Response of Combustion Controls
Reduced O&M costs
Improved Coal Mill Performance
Safety
13. 1. MAKE :- BEIJING POWER EQUIPMENT GROUP
2. TYPE :- DPG50
3. CENTRE DISTANCE OF COAL SUPPLY :- 2500mm
4. RANGE OF OUTPUT :- 5-50 TPH
5. RANGE OF BELT SPEED :- 34-210 mm/sec
6. POWER :- 2.2KW
7. WEIGHT :- 3.6 T
15. COAL FEEDER CONTROL SYSTEM
FEEDER CONTROL
PANEL
SIEMENS BW 500
MILLTRONICS
VFD FOR BELT
MOTOR
16. COAL FEEDER CONTROL SYSTEM
COAL FEEDER PLC &
RELAY
MICROMASTER 440
VFD
PLC & CONNECTION
17. COAL FEEDER PERMISSIVE
PULV RUNNING
COAL FEEDER MIN
COAL FEEDER REMOT CONTROL
COAL LEVEL SPARK PERMIT
COAL FEEDER NO FAILURE
COAL FEEDER INLET GATE OPEN
COAL FEEDER OUTLET OPEN
NO MFT
18.
19. MFT
PULV STOPPED
COAL FEEDER OUTLET GATE CLOSED
COAL FEEDER STRAP COAL OFF
COAL FEEDER BELT DEVIATION
COAL FEEDER OUTLET PLUGGED
TEMPERATURE ALARM FOR COAL FEEDER
20.
21.
22. COAL FEEDER SYSTEM OVERVIEW
THREE SYSTEM USED IN COAL FEEDER
SIEMENS MILLTRONIC BW 500
TELEMECANIQUE TWIDO PLC
SIEMENS MICROMASTER 440 VARIABLE
FREQUENCY DRIVE
23. SIEMENS MILLTRONIC BW 500
The Milltronics BW500 is a full-
featured integrator for use with belt
scales and weigh feeders. The speed and
load signals from the conveyor and scale,
respectively, are processed to derive rate
of material flow, and totalization. The
primary values of speed and load, and
the derived values of rate and total are
available for display on the local LCD, or
as output in the form of analog mA,
alarm relay and remote totalization.
26. WHY SIGNAL ISOLATOR USED
WHEN THE DIFFERENTPOWER SUPPLY USED BY
THE SYSTEM SO SIGNAL SEPERATION IS
REQURE THAT TIME SIGNAL ISOLATOR DEVICE
IS VERY IDEAL FOR THAT PROPOSE.
27. CALIBRATION PROCEDURE
CONDITION
1.Feeder Up & Down gate should be closed.
2.Seal air valve should be closed.
3.Set the frequency 20Hz in Variable frequency drive.
4.No coal on belt.
5.Hot & Cold air damper should be closed
ZERO CALIBRATION
1.First check belt should be empty.
2.Start the belt from local mode (Start Emergency).
3.Press the zero key from MILTRONICS integrator in local panel.
4.After pressing enter key, zero calibration started.
5.Display shows ‘zero calibration is completed’.
6.After completion of zero calibration check the deviation must
be within the (±0.03).
7.But if the deviation is more than (±0.03) again do the zero
calibration for reducing the deviation (By press enter key).
Otherwise press RUN key.
28. SPAN CALIBRATION
1.First put the standard weight of 21.9408kg with clamp (2
nos.) weight 1.5096kg on belt.
2.Start the belt from local mode (Start Emergency).
3.Press the span key from MILTRONICS integrator in local
panel.
4.After pressing enter key, span calibration started.
5.Display shows ‘span calibration is completed’.
6.After completion of span calibration check the deviation
must be within the (±0.03).
7.But if the deviation is more than (±0.03) again do the span
calibration for reducing the deviation (By press enter key).
Otherwise press RUN key.
29. FEED RATE CALCULATION
FEED RATE = M X N
Where M = Mass in Kg
N = Speed (m/s) = 0.210m/s
Mass in Kg = Standard weight/ Idler spacing
= 23.45/0.4 = 58.625 Kg
FEED RATE = 58.625 X 0.210 = 12.31 Kg/sec
= 12.31 x 60 =738.675 Kg/min
= 738.675 x 60 = 44320.5 Kg/hour
= 44320.5/1000 = 44.32 TPH
30. COAL FEEDER VFD SETTING
PROCEDURE.
GO TO P-0010
CHANGE THE VALUE
FROM (0 TO 1) BY
PRESSING UP & DOWN
KEY
GO TO P-1080 (MINIMUM
FREQUENCY)
SET THE MINIMUM
FREQUENCY BY USING UP &
DOWN KEY
PRESS-P
BY PRESSING
UP & DOWN
KEY
PRESS-P (2
times)
SET THE MAXIMUM
FREQUENCY BY USING UP &
DOWN KEY
GO TO P-1082 (MAXIMUM
FREQUENCY)
BY PRESSING
UP & DOWN
KEY
PRESS-P (2
times)
31. TELEMECANIQUE TWIDO PLC
IT IS EXPANDABLE TYPE
PLC WE CAN ADD THE IO
TO THIS PLC. TOTAL 30
NOS DI AND 21 NOS DO
ARE CONNECTED TO THIS
PLC.
32. Sr. No. DISCRIPTION
TYPE
OF IO
ADDRESS
1 Feed coal flow rate low extreme DI I0.0
2 Coal feeder body over temperature DI I0.1
3 Up gate end of open DI I0.2
4 Up gate end of close DI I0.3
5 Coal outlet blockage DI I0.4
6 Coal-free DI I0.5
7 Belt left side off-center DI I0.6
8 Belt right side off-center DI I0.7
9 Coal feeder & mill interlock DI I0.8
10 Belt motor in manual control DI I0.9
11 Belt motor in remote control DI I0.10
12 Open up gate(push-botton) DI I0.11
PLC INPUT/OUTPUT LIST
33. 13 Close up gate(push-button) DI IO.12
IOIIIII0.12
14 Up gate opening rate retain(push-button) DI I0.13
15 Emergency shut-down DI I0.14
16 Protection function put into/exit DI I0.15
17 Frequency converter run DI I0.16
18 Frequency converter failure DI I0.17
19 Thermal overload relay of coal feeder actuation DI I0.18
20 Thermal overload relay of cleaning chain actuation DI I0.19
21 Thermal overload relay of oil pump actuation DI I0.20
22 Coal feeder start in remote DI I0.21
23 Coal feeder stop in remote DI I0.22
24 Meter fault DI I0.23
25 Down gate end of open DI I1.0
26 Down gate end of close DI I1.1
27 Open down gate(push-botton) DI I1.2
28 Close down gate(push-botton) DI I1.3
29 Down gate opening rate retain(push-botton) DI I1.4
30
Thermal overload relay of oil pump actuation down
gate actuation DI
I1.5
34. 31 Coal feeder belt start DO QO.0 Q0.0
32 Coal feeder belt stop DO Q0.1
33 Current & voltage convert DO Q0.2
34 Oil pump motor start DO Q0.3
35 Cleaning chain motor start DO Q0.4
36 Open up gate DO Q0.5
37 Close up gate DO Q0.6
38 Open down gate DO Q0.7
39 Close down gate DO Q0.8
40 Coal feeder run indication DO Q0.9
41 Control system common alarm DO Q0.10
42 Coal feeder over temperature alarm indication DO Q0.11
43 Coal outlet blockage alarm indication DO Q0.12
44 Belt coal-free indication DO Q0.13
45 Feed coal flow rate low extreme indication DO Q0.14
46 Protection actuation indication DO Q0.15
35. 47 Mill interlock actuation indication DO Q2.0 Q2.0
48 Belt off-center indication DO Q2.2
49 Coal feeder ready DO Q2.4
50 Coal feeder fan start DO Q2.6
51 Local auto control DO Q2.4
