High sensitivity methane sensor Amphenol VQ21TBJ suitable for detecting low level combustible gases

Product Overview

The VQ21 is an improved poison-resistant sensor designed for the detection of combustible gases, particularly methane in air mixtures, from 0.1% concentration upwards. It offers no interference from water vapour or carbon dioxide and is suitable for atmospheres where traces of silicone and other poisoning agents may be present. When used with the recommended bridge circuit and mounting arrangement, it provides a minimum sensitivity of 10 mV/% methane. The sensor consists of two matched elements: a detector (red sleeve) and a compensator (black sleeve).

Product Attributes

• Brand: SGX Sensortech(IS) Ltd
• Product Type: Combustible Gas Detector Elements
• Model: VQ21
• Element Identification: Serial number on can (red for detector, black for compensator)
• Detector Label: Red circular label on base
• Origin: Registered in England No.08067077
• Issue: A1A-VQ21 Issue 4, March 2007

Technical Specifications

Specification	Value	Notes
Operation	Continuous	1
Bridge Supply	2.0 + 0.1 V
Bridge Power Consumption	0.75 W max
Typical Average Sensor Current	300 mA
Minimum Sensitivity	10 mV/% methane	2
Linearity	Linear up to 5% methane
Response Time (1 1/4% in 2 1/2% concentration)	2 seconds	2, 3
Maximum Methane Concentration	5 %	4
Trimming Resistor (R)	Supplied where necessary, connected across compensator element	5

Outline Dimensions (2310C)

Ref	Millimetres
A	11.05 + 0.25
B	6.10 + 0.25
C	3.56 + 0.13
D	63.50 min
E	1.02
F	7.37 + 0.51
G	8.20 max
H	9.53
J	1.52

Recommended Mounting Arrangements

Ref	Millimetres
AA	19.05 max
AB	9.53 + 0.13
AC	8.33 + 0.13
AD	8.20 min
AE	19.05 max
AF	9.53 + 0.13
AG	8.20 min

Notes

1. Operation may be under either direct flow or diffusion conditions in appropriate mountings.
2. With open-circuit conditions at the bridge output.
3. The response time is a function of the type of mounting used.
4. If the VQ21 is exposed to greater than 5% methane concentration, the calibration of the instrument should be checked.
5. The elements are supplied as a matched pair with a trimming resistor R of the correct value which is supplied where necessary. The trimming resistor is to be connected across the compensator element.
6. The resistance to poisoning by silicone compounds is partly dependent upon the type of housing within which the elements are mounted.
7. The response to certain of the heavy flammable vapours, especially aromatic substances with side chains, may be lower than that calculated from the conversion (K) factors listed in the preamble.

2411261432_Amphenol-VQ21TBJ_C3659345.pdf

High sensitivity methane sensor Amphenol VQ21TBJ suitable for detecting low level combustible gases Images