OZONE ANALYZER BMT 964 Manual, Rev. 04/2021
40
Warning:
Do not apply more than 2.5 barg gas pressure to the instrument!
The Cabinet is also available with 1/8" or 1/4" compression fittings at the sample gas inlet. The
catalyzing cartridge CAT-35 provides a G 1/8 thread (BSPP 1/8") at the outlet. The power and
signal connectors are waterproof.
The built-in purge unit enables the processor to automatically zero the instrument. The purge
contact is used internally to control the valve and the pump. This purge unit is only activated with
Autozero Interval > 0h. The contact is not available externally.
Automatic zeroing may be initiated in different ways. For a detailed description, see chapter Ze-
roing. After approximately 15 minutes of warmup the first Auto Zero cycle is initiated. After
every purge interval, the processor starts a zeroing cycle. See page 23 on how to change the purge
interval. Factory setting is 24 h.
At the start of each zeroing cycle, the last concentration measurement is used to freeze the signal
outputs (current and voltage) during the whole cycle. The valve and pump then are activated for
about 12 seconds, followed by the zeroing of the analyzer (needs about 1 second). After zeroing,
the display shows the level of contamination of the cuvette (see page 26). Deactivating the valve
and pump allows the ozone gas 12 seconds time to get back into the cuvette before the signal
outputs are set to the current concentration values again.
Ozone Destruct
Care must be taken in using the Catalyzing Cartridge, which may never see water or humidity.
This might damage the catalyst material. The sample gas filter can only keep dirt from entering
the system, but not humidity.
The pressure head at the outlet of the Catalyzing Cartridge must not exceed 100 mbar to the am-
bient. Otherwise the built-in air pump will not bring the ozone out of the cuvette and false zero
readings will be the result.
1
7
6
3
2
4
5
purge command
8
9
ozone
sample gas
under pressure
1
2
3
4
5
6
7
8
9
sample gas filter
throttle valve
3-way solenoid valve
flow meter
ozone analyser
air pump
filter
ozone destruct
cabinet
