Mud Samples for 'Coulter-Counter Analysis'

摘要

The method determines the number and size of particles suspended in an electrically conductive liquid. The suspension flows through a small aperture having an immersed electrode on either side, with particle concentration such that the particles traverse the aperture substantially one at a time. Each particle passage displaces electrolyte within the aperture, momentarily changing the resistance between the electrodes and producing a voltage pulse of magnitude proportional to particle volume. The resultant series of pulses is electronically amplified, scaled and counted. The voltage pulses are displayed on the oscilloscope screen as a pattern of vertical 'spikes.' The pulse pattern serves as a guide for measurement and as a monitor of instrument performance. The pulses are also fed to a threshold circuit having an adjustable screen-out voltage level, and those pulses which reach or exceed this level are counted. Threshold level is indicated on the screen by a brightening of pulse segments above the threshold level. (Author)