" Oxy-2 "Operating Manual

Operating Manual" Oxy - 2 " Residual Oxygen Measuring Instrument

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INTERCON ENTERPRISES INC.

1-800-665-6655TEL: 604-946-6066FAX 604-946-5340

www.intercononline.com

" Oxy-2 "Operating Manual

INDEX 2

PREFACE 3

INTRODUCTION 3 Principle of Measurement 4 Measurement Electronics 5 Sensor 5

GENERAL ARRANGEMENT 5

Description of the Electronics 5 Description of the Sensor 6 Flow Diagram 6

OPERATION 7 Switching on the Instrument 7 Measuring 7 Bottled Gases 8 Process Gases 8 Switching off the Instrument 9

IMPORTANT INFORMATION 9

Estimated Oxygen 9 Tip 9

EXTERNAL PORTS 9

Recorder Port 9

TECHNICAL DATA 10

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" Oxy-2 "Operating Manual

Preface

This instrument determines the partial pressure of oxygen in gas atmospheres by using an oxygen sensor. Such sensors operate at very high temperatures. Precautions must therefore be taken to ensure that no flammable gas mixtures reach either the sensor or the instrument. Should the ceramic of the sensor be damaged, the gas being measured may escape or may be diluted by air. Precautions must therefore be taken to avoid damaging either components or the environment.

Damage to the equipment and false readingscan arise due to incorrect operation, leaks,

corrosion, condensation, etc. Regularservicing of all components is essential.

The oxygen measuring instruments and their accessories are built and tested under continuous quality control in accordance with DIN EN-ISO 9001. The instruments must be installed and used in compliance with all applicable local and specific regulations. The equipment must be periodically checked for accuracy and function depending on its degree of use, and should be checked in accordance with the calibration and test instructions with which it was supplied.

This measuring instrument is not suitable for use with explosive gas mixtures, especially with pure hydrogen. There is a risk of explosion.

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" Oxy-2 "Operating Manual

INTRODUCTION

Principle of measurement

Oxygen measuring instruments are designed to process the output from an oxygen sensor made of stabilised zirconium oxide. This material is a ceramic, also called a solid electrolyte, and is ideally suited at high temperatures as an oxygen ion conductor.Such ion conductors, within a temperature range dependent on the composition of the material, possess the capability to fill empty spaces in their crystal structure with oxygen ions. The oxygen ions attach themselves to a conductive contact surface, normally of platinum.The degree of oxygen concentration in a gas under measurement determines the degree of oxygen activity and thus the quantity of oxygen ions.A sensor consists in principle of a solid electrolyte which is exposed to gas on both sides. One side is in contact with a reference gas, air for example, the other with the gas to be measured. The physical construction of the sensor keeps the two gases apart, so that any mixing is prevented.According to the intended application, both heated and unheated sensors are used. Unheated sensors are normally used in connection with ovens, heated sensors where the gases to be measured are under 600°C (a minimum temperature of between 500°C- 600°C is required by the measurement principle).Heated sensors are held at a set temperature by a controller built into the electronic processor. The temperature of both heated and unheated sensors is measured by the processor and is an essential component in the computation of the oxygen content (oxygen partial pressure).The computation uses the following formula:

Where: R = 8.31 J/mol K

T = Temperature in degrees Kelvin F = 96493 As/mol P1 = Oxygen partial pressure on the reference side at 0.20946 bar P2 = Oxygen partial pressure on the side of the gas to be measuredEMF = Electromotive force in volts

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" Oxy-2 "Operating Manual

ElectronicsThe electronics of the "Oxy - 2" are capable of the following functions:Measuring the rest oxygen component in inert gases and in forming gases. Inert gases are, among others, nitrogen, argon, and helium. Forming gases are gas mixtures of nitrogen and hydrogen.The selector switch controls the operation of the instrument.

SensorThe sensor is integrated in the instrument. The sensor includes the measuring element of platinized zirconium oxide, the heating element and the heating controller. The heating element is required to keep the element at a minimum of 700°C.

General Arrangement

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Selector SwitchDisplay

Position LED:- Inert gas- Hydrogen content

of 2%, 5% and 10%

- Instrument on

Carrying handle and support

Gas inlet

Pump on / off

LEDs: “Pump”, “Active” and “Flow “

" Oxy-2 "Operating Manual

Description of the Measuring ElectronicsThe front of the instrument is divided into two parts:1.The Gas Side: The gas inlet and the display are the visible parts of the sensing process.

2.Display: The display shows the measured values within the range of 0-1000 ppm. Next to the display is a selector switch, whose position is shown by an LED, which ensures that the measured value displayed corresponds to the type of gas being investigated.

Description of the Sensor

Gas Flow diagram

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Gas inlet Gas outlet

Sensor

" Oxy-2 "Operating Manual

Putting into Operation

Switching on the InstrumentThe instrument should be plugged into the correct power supply. The switch below the socket on the rear panel can then be switched on.Once the instrument is switched on, the sensor is preheated to its operating temperature, which takes about 30 sec. Note: During this period, the sensor gives no useable output.When the operating temperature is reached, the LED “Active“ lights up, indicating that the instrument is operational.

Should the gas inlet be open and the gas pump switched on, a value of 999 will display. This value only indicates that the measurement range of the instrument has been exceeded.

Note:The measurement range will regularly be exceeded when the pump is switched on with the gas inlet open. This means that 21% oxygen is in the gas mixture at the sensor, and the range of the instrument is only up to 999-ppm oxygen. This condition does not cause any damage and does not overload the sensor.

The gas to be measured must now be brought into contact with the sensor. The gas pump must now be switched on to draw the gas through the instrument. The switch is located on the front panel. The LED lights up “Flow”, indicating a correct flow.

When the gas is being measured directly from a bottle, care must be taken to ensure that the flow rate will be adjusted so that the just LED “Flow” lights up.Please ensure that the maximum flow rate not exceed 100l/h. (To control the flow rate, a flow meter should be connected to the gas bottle)It is therefore recommended that the pressure regulator on the bottle be completely closed before the bottle is connected to the instrument. The flow meter should then be closely observed while the pressure regulator is slowly opened until the correct rate of flow is reached.

Exceeding the maximum rate of flow can severely damage the sensor.

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" Oxy-2 "Operating Manual

MeasuringWhen the LED ”Active” lights up, the instrument is ready for operation and can determine the rest oxygen in gases. As described above, the maximum flow rate must not be exceeded.Bottled Gases

When synthetic gases such as nitrogen, argon, helium, etc. are being investigated, no preparation of the gas other than pressure regulation is required. Note: Care must be taken not to exceed the maximum flow rate, see above.

Process Gases

General:It is impossible to give an exact set of instructions that would ensure the perfect measuring of all process gases without damaging the instrument that one encounters in today’s environment.As a general guideline, the gases to be measured should be free from dust, condensation and products capable of condensing. Such components can block the gas conduits in the sensor and cause damage.

Hot Process GasesWhen hot process gases are being measured, they are pumped out of the purging process and, suitably prepared, fed to the sensor. The tube by which they are collected may be of metal or ceramic.It is in most cases not necessary to provide a cooling apparatus for the small quantities of gas required for the measurements to be made. The gases cool down to about room temperature during their passage to the sensor. Care should be taken to ensure that the gas conduits have no leaks.

Special Process GasesThere are many processes whose gases contain components, which form solid or liquid condensation, when the temperature falls below a certain value. This condensation can be deposited in the gas conduits to the sensor and either affect the measurement or damage the sensor. The existence of such components should be ascertained before commencing a measurement and steps should be taken to remove them.

Important:When using condensation separators, especially for water, it is important that the collection containers are at the lowest point of the gas conduit system.

There will be a delay in reaching a correct measurement due to the volume of condensation separators and filters.

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" Oxy-2 "Operating Manual

Filter System construction The gas preparation system must be matched to the specific requirements of the gas. A standard system could consist of the following:

1. A water separator, possibly with an automatic condensation drain.2. Coarse filter to remove particles above 50µ (only necessary for very dusty

conditions).3. Fine filter to remove particles above 25µ grain size. It is an advantage if this filter

automatically cuts off the flow of gas in the event of any liquid being deposited.

Switching off the instrumentThe instrument is designed for continuous operation and can therefore be left in the active state. Should it be necessary to switch it off, this can be done with the main switch.

Important Information

Calculated OxygenIn the case of the nitrogen / hydrogen mixture in a so-called forming gas, the oxygen value from the hydrogen reaction with oxygen is calculated and displayed. This procedure is necessary because at a sensor temperature of 700°C the hydrogen reacts with the oxygen and gives rise to an extremely low oxygen partial pressure, whose value is rather academic, when the oxidation potential is being considered. Because of this, a practical measurement technique shows the oxygen value from the above-mentioned reaction in oxygen ppm.Industrial ovens and super hot metal or ceramic parts cause the same reaction between hydrogen and oxygen as in the indicator’s 700°C sensor. Therefore, the above mentioned procedure can be applied.The oxidation potential varies with the proportion of the hydrogen content, so that this becomes an important element in the calculation. The percentage of hydrogen in the forming gas must be set with the selector switch, which allows a choice of 2%, 5% or 10%. These values cover the most common forming gas mixtures.

Note:If the setting of the selector switch does not correspond correctly to the forming gas mixture, this will only lead to an incorrect value being displayed. The function of the instrument will not be affected.

TipAfter a forming gas has been measured, traces of this gas will remain in the surfaces of the gas conduits for some time. Should an inert gas such as nitrogen be measured after a forming gas has been evaluated, the displayed value will fall towards 0 ppm faster than normal. If this occurs, the system should be purged with air before further measurements are done.

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" Oxy-2 "Operating Manual

External Ports

Recorder port This supplies a 0-4 V signal versus 0-800 ppm, synchronised to the display, which is intended for data recording.

Technical Data

Measuring range 0-999 ppm O2

Temperature operating range 0oC bis 45oCAccuracy +/- 0.3 mV Sensor EMFSensor warm-up time Approx. 30 SecondsStabilisation time 10-15 MinutesResponse time Approx. 2 Seconds for variationsDimensions 140mm x 210mm x 225mm (H x W x L)

without handleRequired voltage 230 Volt AC or 115 Volt ACWarm-up load Approx. 200 VANormal load Approx. 40 VA

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Mains Socket and Switch

Fuse Fan

Gas Outlet

Recorder Port

Calibration Screw(only to be adjusted by the

manufacturer)

Carrying handle and support

" Oxy-2 "Operating Manual

Temperature of theMeasuring chamber

Approx. 700 oC

Gas temperature Max. 50oCGas flow Approx. 50 l/h Moisture content Zero. Moisture must be separated out.

Beware of condensation!

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