PM 1200 The paramagnetic O2 sensor
Paramagnetic oxygen sensors are designed for installation in gaz analysers or other systems equipped with microprocessors, PC or PLC controls. In addition to a compact design and high quality standard, the paramagnetic O2 sensors offers a number of advantages:
- fast output of an exact measured value
- practically no cross-sensitivities to other gases
- Wear-free operation
- long lifetime
Description
The PM 1200 paramagnetic oxygen sensor module is designed for incorporation in your analyser-systems or for the solution of oxygen measuring problems using a microprocessor or PLC-system.
The modules are maintenance-free, have a long lifetime, give a rapid and accurate signal response and are virtually insensitive to other gases. It has a compact design which meets high quality standards.
Measuring principle
Paramagnetic (partial pressure measuring with a rotatable glass dumbbell). The sensor is heated up to 55°C. Oxygen is one of few gases showing significant paramagnetic properties which can be used for its measurement using the following method: A small glass dumbbell filled with nitrogen is placed in an inhomogeneous magnetic field within the measuring cell. The system’s position of rest is defined by a light beam, a mirror on the dumbbell and a photo detector. The dumbbell is diamagnetic and tends to turn away from the magnetic field. The paramagnetic oxygen molecules of the sample gas, however, are drawn into the magnetic field, either displacing the dumbbell or forcing it to turn in the opposite direction. The turning is stopped by an opposite magnetic field generated by means of a coil around the dumbbell, the signal of the photo detector (deviation of the dumbbell from its position at rest) determining the necessary current intensity. The difference between the current when pure nitrogen is flowing and the current when the sample gas is flowing across the measuring cell is proportionate to the concentration of oxygen in the sample gas.
Measuring range
- 0-25% O2
- 0 - 100% O2
- 0 - x % O2 (on request)
- x - 100% O2 (on request)
Output signal
- 0 - 1V
- 0 - 4V
- 4-20mA
Gas Connection
- 3mm
- 1/8"
- 5mm internal thread
Flow options
- direct measuring cell flow (10 - max. 150 ml/h)
- internal bypass (17-70 l/h)
- external flow controller for 10-90l/h (delivered component)
Gas preheating
- with preheating