Fixed Gas Detection Sensor Amphenol VQ21TB Featuring Combustible Gas Sensing and Catalytic Oxidation
Product Overview
The VQ21T Series Combustible Gas Sensor Elements are high-power, low-voltage, poison-resistant detectors designed for general-purpose fixed systems. Utilizing the catalytic oxidation principle, these pellistor sensors are capable of detecting a wide range of flammable gases and vapors, including methane in air mixtures from 0.1% to 5% (100% LEL). The VQ21T Series features significant advancements in bead structure, offering enhanced resistance to catalyst poisoning, particularly from silicones, resulting in a substantially longer operational life compared to standard pellistor designs. They are designed to be used in a draught-free environment and require a suitable flame arrestor for safe operation.
Product Attributes
- Brand: SGX Sensortech
- Principle of Operation: Catalytic Oxidation
- Poison Resistance: High, particularly against silicones
- Power Consumption: Low voltage operation
- System Type: Fixed systems
- Marking: Unique serial number, red/black sleeves or cans, resistor color code
Technical Specifications
| Specification | Value | Notes |
|---|---|---|
| Gases Detected | Most flammable gases and vapours | |
| Bridge Supply Voltage | 2.0 + 0.1 V | |
| Sensor Current | 300 mA typical | |
| Sensor Power Consumption | 750 mW max | |
| Minimum Sensitivity | 15 mV/% | Affected by gas flow and mounting geometry |
| Linearity | Linear up to 3% methane | |
| Response Time (t50) | 2 s typical | Dependent on mounting type |
| Maximum Gas Concentration | 100% LEL | Calibration check recommended if exceeded |
| Shock Test | 250 g, 5 blows in each plane | Dependent on mounting conditions |
| Vibration Test | 20 g, 24 cycles from 100 to 3200 Hz | Dependent on mounting conditions |
| Operating Temperature | 400C 500C (Bead heating) | |
| Model Variants | VQ21T (Standard) | Flexible leads |
| Model Variants | VQ21TB | PCB mounting, flexible leads |
| Model Variants | VQ21TS | Solid leads for PCB mounting |
| Model Variants | VQ21TSB | PCB mounting, solid leads |
| Model Variants | Hydrogen Type | Modified for superior performance with hydrogen/reactive gases |
| Outline Dimensions (VQ21T/VQ21TS) | A: 11.05 0.25 mm (0.435 0.010 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | B: 6.10 0.25 mm (0.240 0.010 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | C: 3.56 0.13 mm (0.140 0.005 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | D: 63.5 mm min (2.500 in min) | |
| Outline Dimensions (VQ21T/VQ21TS) | E: 1.02 mm (0.040 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | F: 7.37 0.51 mm (0.290 0.020 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | G: 8.20 mm max (0.323 in max) | |
| Outline Dimensions (VQ21T/VQ21TS) | H: 9.53 mm (0.375 in) | |
| Outline Dimensions (VQ21T/VQ21TS) | J: 1.52 mm (0.060 in) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | A: 11.3 mm max (0.445 in max) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | B: 6.35 mm max (0.250 in max) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | C: 3.69 mm max (0.145 in max) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | D: 40.0 mm min (1.575 in min) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | E: 1.0 mm nom (0.039 in nom) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | F: 7.88 mm max (0.310 in max) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | G: 8.2 mm max (0.323 in max) | |
| Outline Dimensions (VQ21TB/VQ21TSB) | H: 1.5 mm nom (0.059 in nom) |
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