PROJECT

ON

STUDY OF STOCK HOUSE WEIGHING SYSTEM AT H-BLAST FURNACE

1

SUBMITTED BY:-

NAME :- BISHWARUP MUKHERJEE

V.T NO. :- VT20130827

INSTITUTE :-BHARATH UNIVERSITY

DISCIPLINE :- ELECTRICAL

DURATION :- 03 WEEKS

GUIDED BY :-

MR. DHARMENDRA KUMAR

PANDEY (ASSISTANT MANAGER I.E.M. H- BLAST FURNACE)

UNDER,

MR. AMAR MISRA

[HEAD I.E.M (“G” & “H”)

BLAST FURNACE]

CERTIFICATE

Certified that this project “STUDY OF STOCK HOUSE WEIGHING SYSTEM AT H.B.F” is the bona fide of “BISHWARUP MUKHERJEE” V.T NO.:- VT20130827 who carried out the realistic project under supervision.

-------------------------------------------------

(signature)

MR. DHARMENDRA KUMAR

PANDEY

(ASSISTANT MANAGER I.E.M. H- BLAST FURNACE)

UNDER,

MR. AMAR MISRA

(HEAD I.E.M “G” &”H”

BLAST FURNACE)

2

ACKNOWLEDGEMENT

At this pleasing moment of having successfully complete the project I wish to convey my sincere thanks and gratitude to the management of TATA STEEL and S.N.T.I. who provide all facilities to me. I would like to express my sincere thanks to the head of I.E.M. G&H BLAST FURNACE , MR. AMAR MISRA for forwarding me to do this project and offering adequate duration in completing the project. With deep sense of gratitude I extend our earnest and sincere thanks to my project guide MR. DHARMENDRA KUMAR PANDEY (department of I.E.M “H-BLAST FURNACE”) for his guidance and encouragement during the project.

3

INDEX

SL.NO. TOPIC PAGE NO.

1. INTRODUCTION 5

2. WEIGHING SYSTEM & TYPES 5-6

3. STATIC WEIGHING

(I)WEIGH HOPPER

(1) HOPPER

(2) LOAD CELL

(II)PLATFORM WEIGHING

WEIGH BRIDGE

6-7

7

8-11

12-19

19

20-21

4. DYNAMIC WEIGHING

BELT WEIGHER

22

23-34

5. CONCLUSION 35

6. REFERENCES 36

4

INTRODUCTION

WEIGHING :-

weighing is the process to measure the quantity of some substance in a given area by using different equipments for different scales of weighing, after completion of the weighing process the measured quantities are given some units which are recognized globally.

WEIGHMENT :-

weighment is the technical term used to symbolize the process of weighing of raw material in term of S.I. unit or in some case C.G.S. according to the country or region preference.

WEIGHING SYSTEM :-

Weighing system is basically classified into two main categories they are:-

1. STATIC WEIGHING SYSTEM .2. DYNAMIC WEIGHING SYSTEM .

5

STATIC WEIGHING

As the name suggests, the goods or products are stationary when they are being weighed on these scales and usually there is more than sufficient time for the measurement process to stabilize before readings are taken.

There are three types of static weighing :-

6

A)Mech. Weighing B) Weigh hopper C) Platform weighing

(weigh bridge)

“AT HBF ONLY WEIGH HOPPER AND WEIGH BRIDGE ARE USED”

“At H-blast furnace we use weigh hopper for raw material

weighing and weigh bridge for Hot metal weighing purpose.”

WEIGH HOPPERS

A weigh hopper is an item of equipment that is required when there is a need to collect and accurately weigh a product prior to the next process. We primarily manufacture weigh hoppers for measuring shredded materials, but also with the use of our in house design facility for many other applications. All weigh hoppers can be fed by gravity, belt conveyors, screw, vibratory feeders or air conveyors.

7

8

CAPACITY OF WEIGH HOPPER :-9

CONFIGRATION OF WEIGH HOPPER(FIELD DATA ) :-

MATERIAL WEIGH HOPPER NAME

CAPACITY

(tonnes)

NO. OF WEIGH HOPPER

CENTER COKE

CCWH1

CCWH2

13.75t

13.75t 2

SURFACE COKE

CWH1

CWH2

CWH3

CWH4

13.75t

13.75t

13.75t

13.75t

4

SINTER SWH1

SWH2

SWH3

SWH4

76.5t

76.5t

76.5t

76.5t

4

IRON ORE OWH1

OWH2

OWH3

OWH4

60t

60t

60t

60t

4

NUT COKE NCWH 3.75t 1SINTER FINES

SFWH 15.75t 1

ADDITIVE AWH1

AWH2

AWH3

9t

9t

9t

3

DRI DRIWH 9t 1

At HBF the weigh hopper are in the range of :-

(5-90t)-“which are held by 3 LOAD CELL each”.

“ABOVE SHOWN IS THE SIMILER STRUCTURE OF THE WEIGH HOPPER WHICH ARE USED IN THE H-BLAST FURNACE”

PARTS OF WEIGH HOPPER:-

Weigh hopper are made up of two main parts:-

1.Hopper.

2.Load cells.

10

HOPPER:-

Hoppers are the structures which are generally conical at bottom, these structure carry different raw material for the purpose of manufacturing. These structures stores raw material which are balanced by load cells at the bottom. The configuration of the load cell my vary from industries to industries, at HBF three load cells are used for the each hopper, separated by 120 degree apart.

“ABOVE SHOWN IS THE BASIC STRUCTURE OF THE HOPPER.”

11

RAW MATERIAL MOVING PROCESS IN THE WEIGH HOPPER:-

“Above shown is the block diagram of raw material movement in the stock house of h-blast furnace” .

12

LOAD CELLS :-

A Load cell is a transducer that is used to convert a force/weight into an electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire.

A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. Load cells of one strain gauge (Quarter Bridge) or two strain gauges (half bridge) are also available. The electrical signal output is typically in the order of a few mill volts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer can be scaled to calculate the force applied to the transducer.

13

TYPES OF LOAD CELL:-

1. Stainless steel sheer beam load cell.

Capacity - 500kg---5t

Type – N/C3/C3MR.

2. Bending beam load cell.

Capacity - 5kg---500kg

Type – N/C3/C3MR/C3MR+.

3. Precision compression load cell.

Capacity – 100t---300t

Type – L/LA/N/NE.

14

4. Compact compression load cell.

Capacity – 30KG---10T

500KG---5T.

Type – D1/LT.

5. Weigh bridge load cell.

Capacity – 20T---75T.

Type – C3/C4/C5/C6.

6. Compression s-type load cell.

Capacity - 100KG---5T.

Type – D1/C3/C6.

7. Tension s-type load cell.

Capacity - 100KG---3T

Type – D1/C3/C6.

15

“AT H-BLAST FURNACE ONLY PRECISION COMPRESSION LOAD CELLS ARE USED FOR WEIGH HOPPER”

DETAIL ABOUT COMPRESSION LOAD CELL. :-

SPECIFICATION (of PCLC at H-BLAST FURNACE):-

1. No. of load cells used in one weigh hopper = 3.

2. Orientation =each load cell is separated by one another by 120 degree angle.

16

3. Capacity of load cells = 100t---300t(as per requirement)

4. Sensitivity =1mv/v---2mv/v.

5. Supply voltage = 12 volts (dc).

8. Cable identification:-

THE COMPRESSION LOAD CELL BASICALLY HAS,

6-COLOURED CABLES:-

1.RED/BROWN — SUPPLY + (V+).

2.BLUE – SUPPLY – (V-).

3.BLACK – SNESE + (S+).

4.WHITE – SENSE – (S-).

5.GREEN – OUTPUT + (M+).

6.GREY/YELLOW – OUTPUT – (M-).

17

IN SOME CASES (BLACK AND WHITE) CABLE MAY NOT BE

THERE.

INTERNAL STRUCTURE OF A COMPRESSION LOAD CELL :-

ABOVE SHOWN IS THE INTERNAL STRUCTURE OF A COMPRESSION TYPE LOAD CELL.

OPERATION:-

The whole system works on the priciple of the wheat stone bridge,as shown below.

18

When pressure is applied on the load cells then in that case the horizontal as well as the vertical strain gauge which are mounted on a chip sticked to the high modulous metal inside the hemispherical sealed chamber compresses and expands resp. due to which the resistance of the strain gauge changes.because, we know that,

R=ρ LA

Were,

R = Resistance. L = Length A = Area.

when the load is put on the load cell the horizontal strain gauge compresses and due to which the length of the strain gauge decreases and the area increase. Hence, the resistance of the strain gauge also changes accordingly.

And in case of vertical strain gauge the length increases and the area decreases. As,a result of that the resistance also changes.

Inside the sealed chamber there exist a vacuum and pure nitrogen(N) is inserted inside the chamber. this process increases the life of the load cells. On load cell can withstand the load of the weigh hopper for more than 100 years.

CONNECTION OF THE LOAD CELL :-19

“SHOWN ABOVE IS THE CONNECTION DIAGRAM OF A LOAD CELL”.

PLATFORM WEIGHING :-

Platform weighing is a techniqe of weighing by using a plane surface or even surface, this weighing method is applied basically for weighing much larger materials which are not in a regular shape or which cannot be weighed by other piece of weighing process present in the vicinity.

“AT H-BLAST FURNACE IN THE NAME OF PLATFORM WEIGHING WEIGH BRIDGE IS USED FOR THIS PURPOSE.”

WEIGH BRIDGE:-

20

A weighbridge is a large set of scales, usually mounted permanently on a concrete foundation, that is used to weigh entire rail or road vehicles and their contents. By weighing the vehicle both empty and when loaded, the load carried by the vehicle can be calculated.

The key component that uses a weighbridge in order to make the weigh measurement is load cells.

Weigh bridge can be surface mounted with a ramp leading up a short distance and the weighing equipment underneath or they can be pit mounted with the weighing equipment and platform in a pit so that the weighing surface is level with the road. They are typically built from steel or concrete and by nature are extremely robust.

In earlier versions the bridge is installed over a rectangular pit that contains levers that ultimately connect to a balance mechanism. The most complex portion of this type is the arrangement of levers underneath the weighbridge since the response of the scale must be independent of the distribution of the load. Modern devices use multiple load cells that connect to an electronic equipment to totalize the sensor inputs. In either type of semi-permanent scale the weight readings are typically recorded in a nearby hoser hut or office.

Many weighbridges are now linked to a personal computer which runs weigh bridge software capable of printing tickets and providing reporting features.

21

WEIGH BRIDGE CONFIGRATION FOR H-BLAST FURNACE:-

1.quantity :- one

2.total capacity :- 800t.

3.No. of load cells in each weigh bridge :- 4.

4.make :- sartorius

6.sensitivity :- 1mv/v.

22

DYNAMIC WEIGHING

Dynamic weighing covers a wide range of applications either where the product, goods or vehicle are weighed while moving, or the scale itself is moving as with onboard ship scales. Most dynamic applications are considered to be automatic weighing. Filling machines are a large sector of dynamic weighing and therefore are dealt with separately .

Belt conveyors are the fastest mode of material transportation in mining and process industries where bulk material transportation is the important criterion. It is required to measure material transported over these conveyors, In order to achieve consistent quality in the process and accountability. Sartorius Belt weigher are designed to achieve this by delivering consistent accuracy and reliability. Belt weigher is basically a load measurement system installed in a conveyor belt. Which is designed to indicate and record the flow rate of the material conveyed from one location to another location. It will also record the total weight conveyed per unit time. High precisions Sartorius Load Cells are used for measuring the load. Reliable Speed measuring device is used to measure the belt speed. Using these two Parameters (Load & Speed) the material flow rate can be expressed in terms of tonnes/hour. This flow rate output is integrated with respect to time for giving the continuous totalized value of the material conveyed.

23

“AT HBF WE USE BELT WEIGHER UNDER THE CATEGORY OF DYNAMIC WEIGHING”

BELT WEIGHER:-

Belt conveyors are the fastest mode of material transportation in mining and process industries where bulk material transportation is the important criterion. It is required to measure material transported over these conveyors, In order to achieve consistent quality in the process and accountability. Sartorius Belt weigher are designed to achieve this by delivering consistent accuracy and reliability. Belt weigher is basically a load measurement system installed in a conveyor belt. Which is designed to indicate and record the flow rate of the material conveyed from one location to another location. It will also record the total weight conveyed per unit time. High precisions Sartorius Load Cells are used for measuring the load. Reliable Speed measuring device is used to measure the belt speed. Using these two Parameters (Load & Speed) the material flow rate can be expressed in terms of tonnes/hour. This flow rate output is integrated with respect to time for giving the continuous totalized value of the material conveyed

Main features of Sartorius Belt Weighers are :-1. Simple installation and easy maintenance.2. Trouble free operation under severe environmental conditions.3. Practically no effect of belt tension on weighing.4. Remote data transmission.5. High reliability and accuracy.6. Easy integration with supervisory systems.

24

Belt weigher consists of the following components:-

1. Load cells with Belt weighing frame to measure the load.2. Weigh Idlers.3. Speed measuring device (encoder) with mounting. arrangement to measure the speed.4. Encoder mounting arrangement.5. Controller to process load and speed data and display the Flow Rate/totaliser.

The Formula to Calculate the Flow rate is :-

25

Q = P x V x 3600

Were,

Q= Flow Rate in TPH P= Load in kg/m

V= Speed in m/s

CONVEYOR SPECIFICATION :-

Conveyer Capacity : 50 TPH

Belt Width in mm : 800

Bulk density T/m3 : 2.1

Total load on Weigh Frame(Span 0.8Mtr.x Belt load) : 8.55

Speed in M/s : 1.3

Conveyer belt weight : ~7.0 kg/m

Load cell Type : MP 77/12 C3

Tacho Type : Digital

Make : Pepperl

Calibration Rod : 5.5 Kg

Accuracy : +/- 0.5% of FSD

26

BASIC BLOCKS OF BELT WEIGHER

27

THE BELT WEIGHER CONSISTS OF THE FOLLOWINGS :-

1.BELT WEIGHER MECHANICALS:-The Belt weigher platform is a compact, rugged fabricated structural frame. These frames support the weighing idler and are isolated from conveyer stringer. The weighing idler /pre & post idlers are machined to limit the radial run out. The encoder-mounting idler is supported on a pivot frame with pillow blocks. The encoder is coupled to the wheel shaft. This assembly is mounted on or top of the return belt on the conveyor stringer.

Weighing idlerCalibration RodRoller rod is used for calibration purpose. The weight of the rod is calculated based on therated belt load.

“AT H- BLAST FURNACE WE USE 5.5KG LOAD FOR THE CALIBRATION PROCESS”

28

CALIBRATION PROCEDURE OF A BELT WEIGHER :-

1. After the proper installation of weigh frame, the encoder and the controller, calibrate the weighing system.

2. Internal weigh point should be enabled for doing the calibration.

3. Refer to the Pro-X4 instruction manual for programming and calibration.

4. The Belt Weighing System is calibrated at site with a calibration rod of known weight.The weight is punched on the calibration rod.

The process of calibration involves two steps :-a. Static Zero Calibrationb. Static Span calibrationc. Rod calibration

29

a. Static Zero Calibration

This is carried out when there is no load on the belt at “Conveyor off” condition. Select ‘Weighing Point’ from ‘Config’ Menu. Controller Displays “Calibration” menu. For performing a new calibration select “New” from the list and perform ‘Zero Calibration’ when there is no load on the conveyor. Pro-X4 operations manual can be referred for performing the Calibration.

b. Static Span Calibration

Span calibration should be done, after performing ‘Zero Calibration’. Span calibration could be carried out using Calibration rod. All of these are explained in the following sections.

c. Rod calibration

The weight of the calibration rod is punched on the rod however the same can be verified using a weighing scale. Place the Calibration rod on the conveyor and set the Span Value according to the weight of Calibration rod. After the Span Calibration Press “Exit” button, Controller provides an option for saving the Calibration.Now the system is ready for use.

30

2. LOAD CELL :-

Load cells are heart of the system. They are strain gauge based transducers, which converts mechanical force (strain) into electrical signal (mV) when given an excitation voltage.Strain gauges are arranged in a wheat stone bridge network by bonding to the especially designed/machined steel membrane. This is housed in an SS enclosure with inert gas filled and comes with a protection of IP68.When load is applied the resistivity in strain gauges changes proportional to applied load. The change in resistance is converted to electrical signal by givingan excitation voltage. Loadcell will have an integral 4 core cable of standard length. Two cores are connected for supply voltage to the load cell & other two for the measuring voltage from the load cell.

“ABOVE SHOWN IS THE LOAD CELL STRUCTURE USED IN THE H-BLAST FURNACE ALONG WITH THE ROLLER WHICH CALCULATES (TURN/HOUR).”

LOAD CELL SPECIFICATION:-31

Make : Sartorius

Type Of Load cell : Bending beam type

Type No. : MP77/12C3

Housing Construction : Full stain less steel construction, hermetically sealed (IP 67), filled with inert gas

3. ENCODER :-

The encoder coupled to idler senses the speed of the conveyor. The encoder is a digital pulse encoder type whose output frequency is proportional to the speed of the belt. The encoder is excited with 5V DC supply from the controller. The pulse output is fed to the controller.

4. WEIGHING CONTROLLER :-

The X4 controller is microprocessor based multitasking operator system. This controller is equipped with a high precision weighing point and analog to digital Converter. The controller has a VFD display and a multi foil keypad at front side and the process interface at rear side. The controller can be loaded with Belt Weigher application programs.

32

5. ENCODER INTERFACE MODULE :-

Encoder interface is a module for dividing the frequency of the encoder output to required frequency .The input frequency is 0 to 10 kHz and output frequency is 0 to 55 HZ. The divider setting can be selected with the dipswitch selection depending on the requirement. Thee are also

33

annunciation for power On, pulse out, Error and pulse IN and pulse OUT. If the frequency exceeds 55 Hz there is an error output.

6. PANEL :-

The floor mounted panel, with dimension (2100 X 800 X 600) MM to houses 6 set of following X4 Process Controller (PR5510/00) with option cards and Encoder Interface module (ST 5010/00), Also houses the switchgears like MCB, Relays, Terminal blocks, AnnunciationLamps, 24V DC power supply Unit & Service socket. The various input/outputs configured in the panel are as follows.

Annunciations: 24V DC Cluster LED lamps for BELT ON, FAULT & TOT. PULSE.

ANALOG INPUT/OUTPUTSLoad cell Input: mV input from load cell corresponding to load on load cell.

Analog Output:1. 4-20mA corresponding to rate for customer requirement.2. 4-20mA corresponding to Speed for customer requirement.

DIGITAL INPUT/OUTPUT

Inputs:Speed input : encoder (field)

Outputs:

34

Belt ON : This output is given by the controller when the controller receives the speedInput signal from field.

Totaliser Pulse : This is the totaliser pulse output. This interval can be set from the controller i.e. pulse for every 1,2,5 or 10 increment.

Cumulative fault: This is output from the controller for ADC fault, belt overload,belt under load.

7. LOAD CELL EXTENSION CABLE :-

It is very important to note following factors: As the length of the cable increases, the resistance increases. This leads to drop in the voltage. As the electronics is temperature dependent, change in temperature will lead to change in the voltage being supplied to the load cell. Both these above factors will lead to error in readings. As mentioned earlier, a special cable is connected between Cable junction Box and the indicator. It has six cores. Usually any loadcell will have four cores. The two extra cores in this cable are used to sense the voltage reaching the junction box. The indicator has a unique feature of compensating for the change / drops in the voltage such that the reading remains stable. Hence eliminating the error due to above-mentioned reasons.

35

CONCLUSION

Weighing system is an important factor in the accurate production of quality steel to given recipes. Hopper weighing provides total weight indication with pressure compensation and flow rate indication derived from weight data change over time. The load cells provide data for total hot metal weight, poured weight and residual weight in torpedo cars. This makes pouring operations more accurate and better controlled.

Hence,I conclude that this project gives a realistic and technical approach to the stock house weighing system at and tells us about the use of static as well as dynamic schemes at H-Blast Furnace.

36

REFERENCES

http://www.wikipedia.org/ WIKIPEDIA.

http://google.co.in GOOGLE WEB SEARCH.

http://google.co.in /images GOOGLE IMAGE SEARCH.

http://www.enggforyou.com WEIGHING SYSTEM

http://electroschematics.com/ ELECCTRON SCHEMATICS.

http://weighingsystem.co.uk/ DIFFERENT TYPES OF WEIGHING PROCESS

37