Particles in emission outlet streams of various manufacturing processes need to be measured to meet health, safety and environmental regulations. The Goyen range of Particulate Emission Monitors such as the EMP6 and EMP7 use ISE and Triboelectric technology for emissions monitoring and broken bag detection purposes in stand-alone or networked configurations.
The EMP7 utilises ISE technology. Each particle travelling through the process develops an electrical charge. As the particle passes or impacts with the sensing element, a current is induced which is processed in EMP7 by a method called Impulse Signature Extraction (“ISE”).
ISE technology extracts the basic characteristics (the ‘signature’) of the impulsive signals induced by individual particles in the gas stream. ISE technology processes the entire signal from the sensing element, its algorithm effectively negates the potentially erroneous effects of the DC component of the signal, so ISE technology shares all the advantages of existing AC Triboelectric technology.
Made a reality by recent advances in low power digital signal processing, ISE technology is as significant a step forward now as the introduction of AC Triboelectric technology was in 1992.
The EMP6B utilises AC Coupled Triboelectric technology. As particles travel through the process they develop a charge. This charge is transferred as the particle passes or impacts the sensing element. The resulting current is amplified, filtered, rectified and further filtered looking only at the AC component, to give a linear representation of the concentration or mass flow rate of the particles in the gas stream.
The reason for measuring the AC component is that compared to the DC component the electronics are more sensitive. The AC signal is substantially less affected by influences such as amplifier noise and process parameters, which includes the build- up of process dust on the sensing rod. The EMP6B remote Active Head totally filters out any 50 Hz or 60 Hz frequencies related to mains supply. The amplified signal is then sent via data cable to Control Unit for further processing and display.
The EMP7 and EMP6 heads are typically mounted through the wall of a duct carrying the moving particles so that the probe is exposed to the particles. The gas stream often exhausts to atmosphere (such as in a stack), but these emission monitors are equally suited to detecting particles in motion in a gas stream under other conditions, for example pneumatically-conveyed or gravity-fed particles.
Pentair Goyen’s EMP7 and EMP6 Particulate Emission Monitors are are used around the world to measure particle concentrations in various outlet gases and air streams aiming to control the dispersion of noxious substances, improve indoor air quality in workplaces, or prevent harmful dust emissions to be purged into the atmosphere.