Honeywell enCore Series Manual page 56

4
The physical measurement is carried out in the instrumentation section with the aid
of a sensor block containing the electronics for the complete control, regulation,
measurement acquisition and transmission.
A two-channel double block and bleed valve block (DBB) supplies the gases to the
sensor block. Each gas channel is shut off by 2 solenoid valves. There is ventilation
between the valves. This DBB technology prevents the supplied gases mixing, even
if the valves leak. The figure shows a layout of the gas routes. The arrows indicate
the flow direction of the gas. I
The sensor block consists of parts with gas channels as well as the electronics and
sensors. An integral pressure regulator reduces the inlet pressure for measurement.
The measuring system typically operates at a gauge pressure of around 16 KPa ≙
2.32 psi ≙160 mbar. The gas is then supplied to the actual sensor chamber. The in-
frared sensor and the thermal conductivity sensor analyze the gas there and a
pressure transmitter measures the gas pressure.
The block is heated electrically to 70°C ≙158°F ≙343K to ensure stable results. An
installed fan prevents the temperature from rising too high. A temperature sensor
records this block temperature, which is called TSB.
After the measurement the gas is led back into the lower part of the housing. The
typical flow rate is between 1.059ft
l/h to 60 l/h. The flow rate may be changed depending on the application.
GasLab Q2
Measuring method and measuring point
Fig. 4-2: Gas routes in the device
3
/h to 2.118 ft
User Manual (N )
3 3
/h ≙0.03 m /h to 0.06 m
3
/h ≙30
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