gas detection

Gas Detection -New Techniques

Harmful gases in the mines are Carbon dioxide(CO2) Carbon Monoxide (CO) Methane (CH4) Hydrogen (H2) Hydrogen sulphide (H2S) Nitrous fumes

Gas Detection Techniques

Objectives To ensure environmental air quality To ensure dilution of blasting fumes To detect early symptoms of spontaneous heating/fire To assess air composition behind sealed off/sectional areas To conduct blasting operations in free inflammable air mixtures

Mode of Measurement

Conventional system

Air samples analysis

Tube type detectors

Digital Gas Detectors

Gas Chromatograph

Gas Detection

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Mode of Measurement

Conventional system Flame safety lamp Cannery birds Smell indications physiological symptoms

Gas Detection

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Mode of Measurement

Air sample analysis Collection of samples Condition of sampling pippets Transportation time Analysis time Nitrogen calculation by difference

Gas Detection

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Mode of Measurement

Types of Digital gas detectors Various types of portable and transportable gas detection apparatus may be used in a variety of ways according to their particular design and specification. Persons required to use digital gas detectors should have been properly trained in its used and should have ready access to the operating instructions.

Gas Detection

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Types of Digital gas detectors Explosimeter Oxymeter Toximeter Multi gas detector Chip measurement system(cms)

Gas Detection

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Sensors are available for measurement of explosive, toxic and environmentally harmful gases and Oxygen

Gas Detection

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Sensor Technology

Types of sensors:1. Electrochemical Sensors 2. a) Catalytic oxidation sensors (Cat Ex) b) thermal conductivity sensors (heat of reaction) for measuring combustible gases.

3) Infrared sensors (IR) for CO2 and Ex versions

Gas Detection

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Sensor Technology

Electrochemical sensors are transducers for measuring the partial pressure of toxic gasses or oxygen in the ambient air

The ambient air to be measured diffuses through a plastic membrane into the liquid electrolyte of the sensor.

In the electrolyte enclosure, there is a measurement electrode, a counter electrode, and a reference electrode.

Gas Detection

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Electrochemical Sensors

An external electronic potentiostat ensures a constant voltage between the measurement electrode and the reference electrode

The voltages, electrolyte and electrode materials are so chosen that the gas to be measured is converted electrochemically at the measurement electrode while at the same time a current flows through the sensor.

The current is proportional to the partial pressure of the gas being measured.

Gas Detection

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Simultaneously, at the counter electrode, an electrochemical reaction with oxygen from the ambient air takes place

For oxygen, this voltage, the electrolyte and the electrode material are selected such that oxygen is electronically converted at the measuring electrode.

During this process, a current flows which is proportional to the oxygen concentration

O2+4H+4e-=2H2O

Gas Detection

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For toxic gases, the bias is selected such that H2S or CO contained in the sampling air is oxidized at the anode in accordance with

H2S + H2O = H2SO2 + 8H + 8e-

or CO + H2O = CO2 +2H + 2e-

Whereby the current flowing thorough the sensor is proportional to the H2S or CO concentration respectively.

Gas Detection

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The catalytic sensor is a transducer for the measurement of the partial pressure of flammable gases and vapours in the atmosphere.

This sensor functions according to the thermal heat of reaction principle.

The ambient air to be measured diffuses through a sintered metal disc into the sensor, where the flammable gases are then burned catalytically on a heated detector element (Catalytic bead).

Gas Detection

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Catalytic Sensors

The oxygen needed to support this burning process is taken from the ambient air.

The heat generated by the burning process causes the detector element to heat up further.

This heating changes the resistance of the detector element to heat up proportionally to the concentration of the flammable gases .

The voltage measured at the sensor is amplified by the electronics and is displayed in % LEL.

Gas Detection

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Catalytic Sensors

Various compounds absorb infrared energy.They absorb different wavelengths of IR light energy in

different degrees.Higher concentrations of gas will absorb more IR light

energy.Gas is pumped, or diffused into a chamber with an IR light

source.The infrared sensor is a transducer for the measurement of

the partial pressure of ambient gases. This sensor functions according to the principle of the absorption of infrared light.

Gas Detection

Techniques Infrared Sensors

Oxymeter/toximeter(Pac-III)Pac: Personnel Air Control Single portable gas detection instrument for measuring toxic

gases, vapours and oxygen.Technical specifications:

DIMENSIONS : 66 x 110 x 32 mmWEIGHT : 185 gOPERATING HUMIDITY : 10-95 % (RH)

Gas Detection

Techniques Digital Detectors

RANGE OF SENSORS(ELECTROCHEMICAL)CARBON MONOXIDE 0-2000 PPMOXYGEN 0-25 % Vol.

Display: Instrument type, software version, date and time, gas type, measuring range, alarm set points, pre-alarm and final alarm, measured value and measuring unit.

All these features make it convenient when fitting different sensors and for proper calibration of the equipment.

The next calibration date is also displayed.An illuminated display is provided to see in dark.

Gas Detection

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Oxymeter/toximeter(Pac-III)

Alarms: two audio- visual alarms are provided the limits of which are adjustable as per the user needs.The pre-alarm is non-latching and the main alarm is latching.

Self- Test Check: the instrument is provided with self-diagnostics and does a self-test check for the circuits and power supply during starting. Warning signals and error messages for measuring errors, instruments errors, on exceeding measuring range and also in case microprocessor fault.

Gas Detection



Power supply: operated with alkaline/lituium/NiCd battery. The instrument displays battery status , indicates battery replacement, charging status and also gives an alarm for dead battery and automatically shuts down to prevent battery damage.

Operating time: 24 hoursCharging time: 10 hoursCalibration: It enables span calibration, standard

calibration, zero calibration, sensitivity calibration and alarm for no calibration possible.

Gas Detection



Advantages: If different gas hazards need to be measured,

a number of different electrochemical sensors can be kept ready at hand which can simply be connected to the devices as needed.

The flexibility of this measurement system guarantees compatibility with future extensions like new sensors or other accessories.

Gas Detection



It is versatile pocket-size instrument for explosive atmospheres in %LEL.

The instrument can also measure methane in % by Vol.

It is user -friendly and adjustable.Technical Features

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Methonometer( Pac-Ex)

Measuring range0-100% LEL, resolution 1%0-5%Vol CH4, resolution 0.001% Vol.5- 100% Vol CH4, resolution 1% vol.

It is possible to change the measuring range from LEL to Vol % and vice-versa.

Sensor: Plug-in type pellistor sensor which measures by heat of combustion and thermal conductivity.

Sensors life is 3 years.Size : 142 x 66 x 27 mmweight : 370 gOperating Humidity : 5-95% RH

Gas Detection



Self- Test Check: the instrument is provided with self-diagnostics and does a self-test check for the circuits and power supply during starting.

Alarms: It has four gas concentration thresholds fully adjustable with pre-alarm is non-latching and main alarm is latching.

Gas Detection



Power supply: it works with NiCd rechargeable battery. It has an intelligent battery management system. The instrument displays battery status, charging, gives and alarm before 10 min. operating time left for the battery and automatically shuts down with 2 min. to prevent battery damage.

Operating time: 8 hoursCharging time: 8 hours

Gas Detection



It is a portable multi-gas measuring instrument for continuous monitoring of the concentration of several gases in ambient air.

It can independently measure simultaneously four selected gases depending on the installed sensors.

Multifunctional software menu is operated by a three-button key pad. It allows automatic configuration of the instrument according to the installed sensors.

Gas Detection


Multi gas detector( Miniwarn)

Sensors: Plug-in sensors consisting of one catalytic sensor and three Electro- chemical sensors, one each for carbon monoxide, carbon dioxide and oxygen.

Measuring ranges

Gas Detection



Catalytic explosive 0-5% Vol. 0-100% Sensor for Methane LEL & 5 to 100% Vol.Carbon Monoxide sensor 0-2000 PPMCarbon Dioxide sensor 0-5 % Vol.Oxygen Sensor 0-25% Vol.

Display: It continuously monitors and displays complete instrument information including battery

capacity, alarm settings, measuring ranges, instrument fault, sensor fault, calibration information, date and time, instrument warnings, battery alarms etc. The information is also displayed by means of special symbols.

Alarms:Audio -visual alarm activates whenever relevant gas concentration exceeds the predetermined limits.

Alarms for time -weighted average and short-term exposure limit.

Alarm for blockage of flow of gas.

Gas Detection

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Self-Test: It enables self-diagnostic test for the complete functioning of the instrument including

sensor circuits and battery.Calibration: in enables fresh-air calibration, zero calibration

and span calibration. It indicates the next calibration date.Power Pack: it work with nickel metal hydride rechargeable

power pack. It indicates battery status and charging status. For protection of battery life, it first discharges the battery automatically and then charges with indication.

Operating time : 12 Hourscharging time : 8 hours

Gas Detection

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Micro pac is a compact personal gas detection Instrument .

The maintenance free instrument is available in six versions(CO,CO2,H2S AND O2 etc) to monitor the gases in ambient air,

The light weight low-profile design allows it to be worn on the lapel, shirt pocket, helmet or belt.

Measuring Ranges of the Sensors

Gas Detection

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Mini personnel gas detector( micro pac)

Carbon Monoxide sensor 0-400 PPMCarbon Dioxide sensor 0-5 % Vol.Oxygen Sensor 0-25% Vol.Hydrogen sulphide sensor 100 ppm.

Dimensions : 55 x 85 x 35 mmWeight : 120 gOperating Humidity : 10 to 95% RH (5-99% RH

for short periods.

Gas Detection

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Mini personnel gas detector( micro pac)

A gas chromatography system consists of a Carrier Gas, Sample introduction, Column, Detector, Computer.

The sample introduction, column and detector are the key components of the GC instrument.

Gas Detection

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Gas Chromatography

It is a high speed Micro-gas chromatography by which the samples can analyzed within 6 Minutes.

The operation of the GC is made very easy because of the Software Ezgas provided by M/s SIMTARS

samples can be collected by dry in sample bags which are very lighter and minimizes any leakage as the same will be in positive pressure, further there is no breakage like glass pipettes.

Gas Detection

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Gas Chromatography

There is provision of four channels (columns) In column A: Helium, Hydrogen, Oxygen & Nitrogen

are analyzed. In Column B: Exclusively Methane is measure. In Column C: Exclusively Carbon Monoxide is

measured In Column D: Carbon Dioxide, Ethane, Ethylene and Acetylene are measured. Due to the above the peaks of the different gases are

very clear, reliable and easily identified.

Gas Detection

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Gas Chromatography

The GC can be daily calibrated with low span, medium span and high span calibration gases, which ensures the reliability of the gas analysis.

The calibration gases low, medium, high span: the carrier gases, Argon, Helium and the dry air along with cylinders were procured from M/s BOC India as recommended by M/s. SIMTARS.

Gas Detection

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Gas Chromatography

The new Chip Measurement System (CMS) is designed for on-the-spot check of gases and vapors for occupational exposure limits in the workplace.

The CMS combines the practical needs of the user with the power of intelligent technology.

Gas Detection

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Chip Measurement System

Tech. Spe: the analyzer feature a handy robust case combined with an attractive appearance.

The designed was influenced by the ergonomics required for one- hand operation.

Dimensions : 215 x 105 x 65Weight : 730 g

Gas Detection

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Chip Measurement System

Fire ladder

Acetylene C2H2

Ethane C2H6, Ethylene C2H4

Hydrogen H2

Methane CH4

Carbon Monoxide COCarbon Dioxide CO2

Treat

Predict

Prevent

Monitor

Respond

Report

gas detection

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