LACO USER MANUAL - GASCHECK G SERIES
6
© 2018 FLUIDX Equipment, Inc.
The GasCheck G Series contains a heated thermistor bead that transmits
heat to a block of material that remains at a constant temperature. As air
passes through the detector chamber a constant amount of heat passes
from the bead to the block. Gases that are different to air will affect the
rate at which heat transmits from the bead to the block. These rates of
change are measured and displayed as leak rates.
The diagram below shows the basic functionality of the GasCheck Thermal
Conductivity sensor. A fan draws a small flow of gas through the probe and
into the sensing chamber. The thermistor bead heats up when electrical
power is applied. As air passes through the cell a constant level of heat is
transmitted to a Temperature Stable block through the air. This rate of heat
transmission is used to Zero the instrument.
When gases with different thermal qualities pass through the chamber,
the amount of heat being transmitted to the Temperature Stable block
changes. These changes are measured, calculated and displayed on the
GasCheck as leak rates or gas concentrations.
NOTE
Some gases have similar thermal properties to that of
the air, therefore the GasCheck can only detect larger
concentrations of these gases.
NOTE
Some gases have positive and other gases have negative
signals. To simplify the instruments function, the GasCheck
only display changes as positive readings.
NOTE
The GasCheck G2 cannot differentiate between gases.
Selecting a specific gas on the GasCheck G Series allows
the instrument to calculate concentrations of that gas only
if that gas is being detected.