Australian Oxytrol Systems

DS Probe

DS Probe - laboratory grade oxygen probe

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  DS probe - overview

The type DS oxygen probe is a laboratory grade oxygen probe, suitable for measurement of oxygen concentration over the range from pure oxygen down to 10-24 atmospheres at temperatures from 700°C to 1700°C.

Specifications

Thermocouple:R-type
Oxygen output signal:DC millivolt, according to Nernst equation
Oxygen measurement range:1 atm. to 10-24 atm.pO2
Operating temperature:700°C to 1700°C
Accuracy:within 2mV of theoretical output

Gas-tight seal for scientific laboratory use

For scientific laboratory use, a gas-tight seal is often required at the insertion point. The DS probe has a vaccuum sealed, stainless steel extension tube over the first 50 mm of the sensor. This extension tube can easily be fitted into an O-ring seal.

Construction

The type DS probe consists of a SIRO2 oxygen sensor with an internal thermocouple, with a small industrial thermocouple head with all electrical and reference air connections. All wiring and electrodes are platinum, for the best possible corrosion resistance and refractoriness.

A ceramic sheath over the sensor is an option. A sheath is useful to protect the platinum wire if the probe is frequently removed and re-installed. The standard sheath material is limited to 1300°C (2400°F). High temperature sheaths are available on special order - please enquire.

Read the probe measurements with the type AIC hand-held digital meter, for a quick and simple indication.

Probes include a 4-pin Cannon type cord plug, ready for connection to any suitable 4-conductor cable.

We recommend a shielded umbilical cable for greater accuracy over long cable runs. We supply a braided four wire cable with a Cannon plug at each end. We use R-type thermocouple compensation wire in the cable. A reference air hose is also fitted in the cable.

Applications

This probe is accurate enough for research laboratory use, but low in cost.

Installation

Install the probe anywhere in the kiln or furnace. If the probe is used at temperatures over 1100°C, the ceramic tube should hang vertically, to avoid bends caused by high temperature creep.

The probe will measure the oxygen concentration at the probe tip, provided that the operating temperature is between 700°C and 1700°C.

When fitting or removing a probe with a hot furnace, move the probe slowly to avoid thermal shock of the ceramic components. Slide the probe in at a rate of approximately 50 mm per minute. The thermocouple read-out can be used to ensure that the heating rate is less than 100°C per minute.

Seal the installation port to prevent atmospheric air from flowing inwards and causing a local variation in the oxygen concentration.

Connections

The probe head must be at a temperature less than 60°C.

Supply clean respirable reference air at a rate of 10 cm3/min to the connection provided on the probe head. A small fish aquarium air pump can provide reference air cheaply and reliably.

The electrical connections are:

Pin 1Pt/Pt13%Rh leg of R-type thermocouple
Pin 2Pt leg of R-type thermocouple
Pin 3Oxygen sensor internal conductor
Pin 4Oxygen sensor external conductor

Output

The oxygen signal is according to the Nernst equation.

Maintenance

There are no user serviceable parts inside the probe. If the external platinum conductor is broken, it can normally be rejoined without loss of accuracy.

Ordering & Information

Probes are specified as "DS-xxx", where xxx is the insertable length, from the probe head to the tip of the sensor, in mm.

If you need an umbilical cable, please specify the length in meters. Please send a request for quotation, specifying delivery address and required length to Australian Oxytrol Systems. Probes are normally ready for despatch by international air freight within two days of order. If you have a preferred carrier or you wish to use your own account, please specify details on the order.

Please note that all prices are in Australian dollars. Please see the Commonwealth Bank currency converter to calculate the price in your currency.

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  DS probe head - view of connection socket