Abstract: A phenomenon that liquid level is low at the edge and high in the middle appears to cause the measuring errors due to the surface tension of the injected liquid when the cartridge volume is measured by water injection weighing method. A high precision measuring system based on the water injection weighing method is proposed. In the proposed system, the array electrodes are used to measure liquid level to overcome the effect of the liquid surface tension. The sensor signal is picked up by a specially made electrode, and then it is transmitted to a computer through a wireless module to control the flow until the cartridge is filled with the water, so as to achieve the purpose of accurate measurement. The accuracy of the system is analyzed. The analysis result shows that the accuracy of the system is up to 0.01%, which meets the requirement of precision index.

Key words: ordnance science and technology, high precision, volume measurement, array electrode, liquid surface tension