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Combustible Gas Pellistor - CH-A3

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• Detection range: 0-100% LEL methane
• Sensitivity: 15~21mV / % methane
• Response time: 15s
• Zero: ± 20mV in zero air
• Linearity: 6% methane when 5% non-linear
• Voltage: 3.0V (±0.2 V)
• Power consumption: 190mW
• Weight: < 26 g
• Operating life: > 24months

Model Number: CH-A3
Data Sheet:

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Product Specification

CH-A3 Combustible Gas Pellistor Description
Alphasense flammable gas pellistors are available in two housing sizes: A for fixed installation applications and A or D for portable applications.

The innovative design of the Alphasense pellistor range provides high quality, low power (only 190mW) and excellent poison resistance. All pellistors are housed in certified flameproof chambers.

CH-A3 is a drop-in (20mm diameter) replacement to existing products with improved stability and poison resistance.

CH-A3 Combustible Gas Pellistor PERFORMANCE
Sensitivity	mV / % methane	15 to 22
Response time	t90 from air to 50% LEL methane (s)	< 15 (typically < 7)
Zero	mV in zero air	±20
Range	% LEL methane	0 to 100
Linearity	% methane when 5% non-linear	6

CH-A3 Combustible Gas Pellistor ENVIRONMENTAL
Sensitivity @ -20°C	% sensitivity change, referenced to 20°C	< 100.5 to 105.5
Sensitivity @ 50°C	% sensitivity change, referenced to 20°C	< 100 to 103
Zero @ -20°C	% LEL change, referenced to 20°C	< +0.5 to -2
Zero @ 50°C	% LEL change, referenced to 20°C	< 0 to -1.5
Temperature Range	Certification to T4	-40 to +55°C
Humidity	12% sensitivity loss from 0% to 80 % rh (22°C) Typical zero increase % LEL from 0 to 80 %rh (22°C)	1.0
Pressure	Sensitivity change from 0 to 75 kPa (gauge)	< 3%

CH-A3 Combustible Gas Pellistor INHIBITION/POISONING
Chlorine	12hrs 20ppm Cl2, 50 % sensitivity loss, 2 day recovery	< 10% loss
Hydrogen Sulfide	12hrs 40ppm H2S, 50 % sensitivity loss, 2 day recovery	< 50% loss
HMDS	hrs until 50% activity loss @ 10ppm HMDS	9
Optional H2S disposable filter can be ordered. Part no. ASF-1

CH-A3 Combustible Gas Pellistor ELECTRICAL
Voltage	V (±0.2 V)	3.0
Power consumption	mW	190
Voltage sensitivity	% sensitivity change / 0.1V change	3

CH-A3 Combustible Gas Pellistor KEY SPECIFICATIONS
Weight	g	< 26
Operating life	months until 75% original sensitivity (24 month warranted)	> 24

Sensitivity

Hydrocarbon/Gas	% Sensitivity relative to Methane	% LEL Sensitivity to Methane
Hydrogen	130 to 140	160 to 175
Propane	150 to 190	350 to 450
Butane	150 to 180	420 to 500
n-Pentane	180 to 200	600 to 670
Nonane	150 to 170	800 to 950
Carbon Monoxide	42 to 44	17 to 18
Acetylene	150 to 170	300 to 340
Ethylene	150 to 170	270 to 320
Isobutylene	180 to 200	450 to 500