Biogas Operating Manual
Page 20
Geotechnical Instruments (UK) Ltd
BMUK0001 / Issue 1
7. Technical
Specification
POWER SUPPLY
Battery type
Rechargeable Nickel Metal Hydride battery pack containing six
4AH cells (not user replaceable)
Battery life
Typical use 10 hours from fully charged
Battery lifetime
Up to 1000 charge/discharge cycles
Battery charger
Separate intelligent 2A battery charger powered from mains
supply (100-240V 47-63Hz)
Charge time
Approximately 2 hours from complete discharge
Alternative power
Can be powered externally for fixed in place applications.
Contact Geotechnical Instruments (UK) Ltd for further
information
Memory backup battery
Lithium Manganese for data retention.
GAS RANGES
Gases measured
CO
2
and CH
4
By dual wavelength infrared cell with
reference channel
O
2
By internal electrochemical cell
H
2
S 0-5000ppm
By external gas pod
Oxygen cell lifetime
Approximately 3 years in air
Range CH
4
0 - 70% to specification, 0-100% reading
CO
2
0 - 40% to specification, 0-100% reading
O
2
0 - 25%
Typical accuracy
Gas
0-5% vol
5-15% vol
15%-FS
CH
4
±0.5%
±1.0%
±3.0%
CO
2
±0.5% ±1.0% ±3.0%
O
2
±1.0% ±1.0% ±1.0%
Response time, T
90
CH
4
20 seconds
CO
2
20 seconds
O
2
20 seconds
FACILITIES
Temperature measurement
With optional probe -10°C to +75
°
C
Temperature accuracy
±0.2ºC (± probe accuracy)
Visual and audible alarm
User selectable CO
2
, CH
4
and O
2
alarm levels
Communications
RS232 protocol with variable baud rate
Relative pressure
±500 mbar from calibration pressure
Relative pressure accuracy
•
±4mbar typically (should be zeroed before reading)
•
±15mbar max
Static pressure measurement
±500 mbar
Static pressure accuracy
±4mbar typically (should be zeroed before reading)
Differential pressure measurement
±125 mbar
Differential pressure accuracy
±0.5mbar typically (should be zeroed before reading)
Available memory
100 Complete readings
PUMP
Flow
300cc/min typically
Flow fail point
50cc/min approximately
Flow with 200mbar vacuum
250cc/min approximately
Vacuum pull
400mbar approximately
