Piezo Balance Type Digital Dust Meter Model 3521

This is a dust meter that directly displays the real-time suspended particulate matter concentration value (mg/m3).

The piezo balance method using a quartz sensor has very little influence from the physical properties of dust, allowing measurements even when the nature of the dust is unknown in advance. ■ Measurement Principle Aerosols enter the main unit through the impactor inlet at a suction flow rate of 1L/min. The particles that pass through the impactor (based on aerodynamic particle size) enter the electrostatic collector. The particles in the aerosol are charged in a strong electric field generated by corona discharge and are electrostatically collected on the piezoelectric element electrode. The corona current is controlled to remain constant at around a few microamperes. The frequency deviation caused by the mass of the particles deposited on the piezoelectric element is processed through a calculation circuit and converted into mass concentration for display. When the amount of accumulated dust exceeds a predetermined value, a cleaning indication is shown. The progress towards cleaning is displayed as a bar graph, and the elapsed measurement time is also shown as a bar graph. The cleaning process is designed to be simple, allowing it to be performed by inserting and withdrawing a cassette.

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