Principles of Operation

Step 1. Oxygen is attracted into a magnetic field. Most other gases are not. This property is used to measure the partial pressure of oxygen.

	Step 2 Servomex’s approach is to mount two nitrogen-filled glass spheres onto a suspension. This assembly is free to oscillate at a natural frequency within a non-uniform magnetic field.

Step 3. Any oxygen that is present within the sample gas will be attracted into the strongest part of the magnetic field. This will alter the natural oscillation frequency.

	Step 4. A conductive coil is mounted onto the suspension, forming a single turn dc motor/generator assembly.

Step 5. If an impulse current ‘I’ is applied to the coil, the assembly will operate as a motor and the suspension will rotate.

Step 6. At the end of the impulse current, the suspension will be free to oscillate and will then act as a generator inducing an EMF into the coil. The oscillation period of the induced EMF will be dependant upon the partial pressure of oxygen surrounding the suspension. The difference between the oscillation period for an oxygen sample, and that for nitrogen, allows an accurate measurement to be made.

Step 1.