CONTINUOUS DUST EMISSION MONITOR PARTICULATE MONITOR Manufacturing in india, manufacturing in mumbai. Process Trend Monitor and Multi-Purpose Dust Alarm With Display. A Real time Continuous indicative dust monitor with logging & alarm capability. Low Cost Solution to Monitoring Requirements. The Stack Guard series operate on the principle of Tribo - Electric charge transfer. The electrical charge carried by dust particles is captured by a highly sensitive Tribo - Electric probe, amplified and then transmitted to the control unit. As the current generated by the charge is proportional to the concentration of particles present, an indicative signal of dust presence results.