Walsn Oxygen Analyzer

Overview

Walsn Oxygen Analyzer is designed to measure the continuous oxygen concentration in combustion flue gases of boilers and furnaces. Walsn Oxygen Analyzer uses a non-sampling (wet) analysis method. It consists of detecting unit (oxygen probe) and control unit (transmitter).

The flue mounted probe has a thermostatically controlled heated Zirconia oxide sensor located at the flue end of the probe. The control unit is designed for use with the Zirconia sensor type oxygen probe.

The control unit offers a centralized termination for functions such as an automatic calibration box, external calibration contacts, status relay contacts and analog and serial outputs.

Virtually no maintenance is required. Repair can be carried out quickly and simply: the internal components can be withdrawn from the probe and replaced as one unit.

The probe will safely operate under start-up conditions for all conventional boiler fuels,provided the fuel ignition temperature is greater than 200°C/392°F.

Measuring Principle

Walsn Oxygen Analyzer contains a zirconia oxide sensing element, comprising a thimble-shaped zirconia cell fitted with inner and outer electrodes at its closed end.

The inner electrode is exposed to the flue gas entering the open end of the cell; the outer electrode is supplied with air from a pump or regulator and is therefore exposed to a constant partial pressure of oxygen.

Since zirconia is an electrolyte which conducts only oxygen ions at temperatures in excess of 600°C/1112°F, the voltage generated between electrodes (i.e. the cell output) is a function of the ratio of the oxygen partial pressure on the inner electrode and its temperature. Therefore, any change in the oxygen partial pressure of the flue gas at the exposed electrode produces a change in the cell output voltage as dictated by the Nernst equation.

Measuring System

Walsn Oxygen Analyzer consists of a detecting unit (oxygen probe) and a control unit (transmitter)

Integral version: The detecting unit and the control unit form a single mechanical unit.

Model: OAM-800 (The user interface includes a four-character display, a set of condition indicator LEDs and a tactile keyboard with cursor controls)

Remote version: The detecting unit is mounted separate from the control unit.

Model: OAM-800-R

Detecting unit: WOR800RD

Control unit: WOR800RA (The user interface includes a four-character display, a set of condition indicator LEDs and a tactile keyboard with cursor controls)

Features

1) Single point, straight plug sensor which can achieve a quick, accurate and reliable measurement, measurement accuracy within the 1% range.
2) Field replacement, easy daily maintenance.
3) Output signal system complies with a user’s on-site monitoring requirements, and can be connected to any process control equipment.
4) Automatic calibration.
5) Power consumption gives longer longevity.
6) Use platinum to lead a derived analog signal.
7) Zirconium cell diagnosis function, which can check Zirconium cell operation statuses, as well as prompt fault alarm information.
8) The Zirconium cell boasts a nanoscale coating technology, and platinum welding process to ensure an air tight seal, durable working life and high measurement accuracy.
9) Built-in heaters ensure a stable working temperature of the Zirconium cell resulting in longer working life.

Input

1) Application fields.
2) Boiler type (Tangential-fired Boiler/ Wall-fired Boiler/W-flame Boiler/CFB).
3) Flue thickness.
4) Type of fuel (fuel oil/fuel coal/gas).
5) Sulfur content in fuels.
6) Flue gas temperature.
7) The flue gas dust concentration.
8) Flue gas humidity.

Output

Analogue outputs：Single channel isolated 0 to 10 mA; 0 to 20 mA; 2 mA to 20 mA; 4 to 20mA menu selectable.

Parameters：

O2 concentration
Calibration gas
Cell temperature
Fault messages
Cell/Thermocouple Information

Serial output：RS485 Modbus protocol

Fault indication：LED indication and error codes