This document discusses Hindustan Zinc Limited's use of level switches in their mining process. It provides an introduction to HZL, describing that they obtain zinc from zinc blende ore mines located in Rajasthan and Orissa. It then discusses the TEL-280 conductivity type level switch that HZL uses to control liquid levels. The level switch operates using two or three electrode probes to indicate high, low, or minimum/maximum liquid levels and includes a time delay circuit to avoid relay activation from turbulent fluids.

1. HINDUSTAN ZINC LIMITED
“LEVEL SWITCHING”
FROM:-29TH MAY to 11TH July 2012
By
Sameer Gupta
B.TECH (ECE)
2010 to 2014
Department of Electronics & Communication Engineering
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2. Index
1. HZL Introduction
2. Mission of HZL
3. Introduction of level switch
4. Block diagram
5. Low and high level control
6. min/ max level control
7. Conclusion
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3. HZL INTRODUCTION
There are many places in our country, where we
get different types of metallic substances as raw
material for industries. In these substances, the metals
are present in compound form. These substances are
called as minerals. Minerals are mostly present as
oxides, sulphides, carbonates, chlorides and silicates.
Those minerals from which we can get the metals
conveniently and at low cost are called ores.
Zinc is mainly obtained from its ore Zincs Blende (ZnS)
available mainly in the states Rajasthan and Orissa.
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4. Jawar
maines
Rampura Rajpura
agoocha
mines debari
mines mines
Manton
rock
phosphate
mines
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5. smelters
Chanderia Lead
Zinc Smelter Debari Lead
Zinc Smelter
5
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6. Uses of Zinc
1. Zinc Powder
2. Bras Items
3. GI pipes
4. CuSO4
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7. Production Capacities
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8. MISSION OF HZL
1. Be a lowest cost zinc producer on a global scale,
maintaining market leadership.
2. One million tone zinc-lead metal capacity by 2015.
3. Be innovative, customer oriented and eco-friendly,
maximizing stake-holder value.
4. Refined zinc production capacity 69,000 tons per
annum.
5. Refined lead production capacity 85,000 tons per
annum.
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9. Process Of Making Zinc
In the Hindustan zinc debari there are two types of smelting process.
Pyro Metallurgy Hydro Metallurgy
But it use the mainly Hydro Metallurgy.
Hydro Metallurgy consists 5 steps for refining of zinc and by product.
Hydro Metallurgy have following 5 steps:-
Roasting
Leaching
Purification
Electrolysis
Melting And Casting
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10. Level Switch
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11. Introduction (Level Switch)
In the mining process we have to control the level of
liquid. Suppose the calcine is flowing through the
pipe to the a big container we have to use level
switch. In the process there are many type of level
switch as follow:-
Capacitance Type Level Switch
Conductivity Type Level Switch
Radar Level Sensor
Ultrasonic Level Sensor
In the Hindustan zinc debari we use
conductivity level switch. It is use for controlling the
level of liquid. For this we use the series TEL-280.
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12. TEL -280 LEVEL SWITCH
• The series ‘280’ Electronics level switches are point
level indicators which indicates the presence of,
absence of conductive media when media come to
contact with electrodes. These are basically
available in three types.
• Low Level indicating Type
• High level indicating Type
• Min/Max Level control Type
• These Level switches generate signal utilizing the
media’s conductivity property. So these switches
are suited for only conducive medias.
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13. BLOCK DIAGRAM
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14. Description
• TEL -280 electronics consist of two PCBs.
The first PCB contain :-
power supply circuits,
 Relay,
 relay driving cuts.
A terminal strip for input/Output connections
are also provided on this board.
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15. The second PCB consists:-
 amplifier,
 time delay cuts
 The A.C. current through the media in between the probes in
amplified by the amplifier and drives the time delay circuits, and
finally the relay. Sensitivity present potentiometer is in
corporporated to suit the switch to medias of different
conductivities.
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16. LOW OR HIGH LEVEL CONTROL
• For Control of LOW Or HIGH liquid level TEL-280
utilize two electrode probe.
• The bigger of the two electrodes is called
common electrode.
• To avoid of the relay due turbulent fluid, a time
delay CKT is incorporated.
• For high level detection, relay will be energized
when fluid reaches the high level.
• for low liquid level, relay will be de-energised
when fluid reaches the Low level.
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17. MIN/MAX LEVEL CONTROL
• For control of preselected MIN/MAX (L0/HI)
liquid level.TEL-280 utilizes three electrode
probes.
• They are common, LOW and HIGH electrode
and their lengths are in above order.
• The difference between high and low (MAX
and MIN) can be as a low 10 mm and may be
as a several meters.
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18. PROPERTIES OF LEVEL SWITCH
Suitable for switching at different levels.
No moving parts, so free from maintenance.
Not affected by material build up on the probe.
Selectable HIGH/LOW level alarm.
Adjustable sensitivity.
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19. Level Sensors Manufacturers
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20. THANK YOU
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