Product Overview

The VQ5 Series Thermal Conductivity Gas Detector Elements are designed for the detection of gases in 0-100% by volume concentrations. Operating on the thermal conductivity principle, these elements feature a sensing element exposed to the atmosphere under test and a reference element sealed in reference air. The response is determined by the difference in thermal conductivity between the test atmosphere and the reference air. The VQ5 series is available in two models: VQ5M with braided leads and VQ5MB with extended pins for direct PCB fitting. These detectors are suitable for various mounting arrangements, including direct flow or diffusion conditions.

Product Attributes

• Brand: SGX Sensortech(IS) Ltd
• Series: VQ5
• Element Identification: Serial number (red on sensing, black on reference), red circular label on sensing element base.

Technical Specifications

Model	Description	Bridge Supply	Bridge Power Consumption	Typical Response to Methane in Air (Open Circuit)	Response Time	Mounting	Shock Test	Vibration Test	Outline Dimensions (Millimetres) - A	Outline Dimensions (Millimetres) - B	Outline Dimensions (Millimetres) - C	Outline Dimensions (Millimetres) - D	Outline Dimensions (Millimetres) - E	Outline Dimensions (Millimetres) - F	Outline Dimensions (Millimetres) - G	Outline Dimensions (Millimetres) - H	Outline Dimensions (Millimetres) - Sensing Element	Outline Dimensions (Millimetres) - Reference Element
VQ5 / VQ5M	Flexi-leg sensor with compensator can. VQ5M has a sealed compensator can.	2.0 + 0.1 V	0.48 W max	1.0 mV/% methane	See note 3 (function of mounting)	See page 3	250 g, 5 blows in each plane	20 g, 24 cycles from 100 to 3200 Hz	11.05 + 0.25	6.10 + 0.25	3.56 + 0.13	63.5 min	1.0	*	8.2 max	9.53	6.25 + 0.50	7.75 + 0.38
VQ5B / VQ5MB	PCB legged sensor with compensator can. VQ5MB has a sealed compensator can.	2.0 + 0.1 V	0.48 W max	1.0 mV/% methane	See note 3 (function of mounting)	See page 3	250 g, 5 blows in each plane	20 g, 24 cycles from 100 to 3200 Hz	11.05 + 0.25	6.10 + 0.25	3.56 + 0.13	40.0 min	1.0	*	8.2 max	1.5	6.25 + 0.50	7.75 + 0.38

Note 1: Operation may be under either direct flow or diffusion conditions in appropriate mountings.

Note 2: With open-circuit conditions at the bridge output.

Note 3: The response time is a function of the type of mounting used.

Note: No bends may be made in the length indicated by F.

Thermal Conductivity of Gases (Relative to air):

Element Temperature (C)	0	100	200	300	400	500	600
Air	1.000	1.000	1.000	1.000	1.000	1.000	1.000
Nitrogen	0.996	0.993	0.997	0.999	0.998	0.994	0.988
Oxygen	0.987	1.026	1.049	1.062	1.065	1.062	1.056
Argon	0.686	0.687	0.682	0.674	0.663	0.650	0.636
Carbon dioxide	0.621	0.745	0.832	0.893	0.933	0.959	0.975
Water vapour	0.969	1.076	1.192	1.303	1.404	1.493	1.574
Methane	1.244	1.500	1.723	1.911	2.066	2.192	2.296
Ethane	0.742	1.027	1.271	1.474	1.638	1.769	1.874
Propane	0.619	0.874	1.092	1.271	1.415	1.529	1.619
Carbon monoxide	0.961	0.962	0.970	0.975	0.976	0.974	0.970
Ethylene	0.703	0.970	1.195	1.378	1.524	1.637	1.727
Acetylene	0.886	1.040	1.155	1.240	1.301	1.344	1.376
Hydrogen	7.371	6.918	6.692	6.548	6.435	6.336	6.252
Helium	5.972	5.681	5.492	5.338	5.197	5.062	4.939
Ammonia	1.082	1.295	1.493	1.670	1.824	1.955	2.069