8
2.2.
Explosive, toxic gas and oxygen metering sensors
The removable, interchangeable and intelligent sensor blocks are made of catalytic, electrochemical
or IR sensor and electronic components, including an “EEPROM” memory in which INDUSTRIAL
SCIENTIFIC- has stored the sensor's specific characteristics (measuring range, various correction
coefficients, STEL and TWA alarms, date of manufacture, serial number, etc.).
Another parameter called the "wear rate" is used by the BM25 to automatically determine the
optimal time to replace the sensor.
These sensor blocks, also called “intelligent blocks,” are plugged in as indicated in Chapter 2.1.
Caution: Silicon vapors or other “poisons” may have an adverse effect on explosive gas
detection sensors and distort measurements (under-estimated measurements).
If the instrument is used in poisoned atmospheres, calibrate it before its next use.
3
3
.
.
DISPLAY UNIT
This is an LCD type display unit which lights up automatically in backlit mode in alarm or fault
conditions and the display can be reversed.
It shows:
-
five measurements for units, type of gas and the presence of a catharometer.
-
a calibration reminder
-
the date and time
-
minimums- maximums
-
the mean STEL and TWA values
-
the remaining battery time (bar graph)
-
operator identification (roundsman function)
-
maintenance menus
-
alarm transfers
4
4
.
.
VISUAL INDICATIONS
An indicator light (made of 20 ultra-bright LEDs) installed on top of the instrument indicates alarm
conditions and can be seen from all directions.
5
5
.
.
AUDIBLE ALARMS
The operator is also warned when an alarm is triggered by two very powerful, built- in horns (103
dB @ 1m).
6
6
.
.
SAMPLING
The BM25 gas detector can be equipped with an internal electrical pump or an external manual
pump to measure gas concentrations in inaccessible locations or in locations needing to be verified
before access.
