Application of Capacitance Sensor in Dynamic Measuring Molten Tin Surface

摘要

The working principle and the structure characteristic of a capacitance sensor have been summarized. Based upon the principle of heat conduction a new method that the pottery is used for the insulation material between the three electrodes of the capacitance sensor is put forward. So the accuracy and the sensitivity for the measurement of a molten tin surface are increased with the new capacitance sensor at the environment of high temperature of 700°C. Through analysis and calculation on a large number of dynamic measuring data, the corresponding relationship between the output signal of the capacitance sensor and the molten tin surface is established. A non-linear compensation is applied to the capacitance sensor system, therefore a key measuring problem that how to measure the gap between a CVD coating reactor and the molten tin surface in the production of floating glass coating has been solved. The test result proves that the dynamic measuring accuracy reached 0.1mm within the effective range of 25m above the molten tin surface of 25mm. It also shows that the measuring system is reliable and feasible.