1. Description:

The Honeywell 2106B2311 is a Sensepoint High Temperature (HT) Flammable Gas Sensor with an M25 thread. It’s a sealed, disposable sensor designed for continuous point detection of combustible hydrocarbon gases (flammable gases) in hazardous industrial environments, specifically those characterized by high operating temperatures. This sensor employs catalytic bead (pellistor) technology, known for its reliability in detecting gas concentrations up to 100% LEL (Lower Explosive Limit). As an ATEX-certified component, it is designed for installation within a suitably approved Ex e (increased safety) or Ex d (flameproof) high-temperature junction box, fitted with approved cable glands. The sensor provides an mV bridge output, which requires a separate transmitter or controller to convert it into a standard industrial signal (like 4-20mA) for integration into a control system.

2. Application Scenarios:

Consider an industrial facility that manufactures specialty chemicals, where processes involve exothermic reactions or high-temperature drying stages, leading to elevated ambient temperatures and the potential presence of flammable solvent vapors. Traditional gas detection equipment might fail or give inaccurate readings in such extreme heat. The Honeywell 2106B2311 Sensepoint HT Flammable Sensor (ATEX) M25 is uniquely suited for this demanding environment. Multiple sensors would be strategically positioned within high-temperature process enclosures, near heated vessels, or in exhaust ventilation systems, all housed in appropriate hazardous area junction boxes. These sensors constantly monitor for any accumulation of flammable gas or vapor. If the concentration exceeds a predetermined safety threshold (e.g., 10% LEL), the sensors would trigger alarms, alerting operators and potentially initiating automated safety responses like system shutdowns or activation of inerting systems. This directly addresses the critical need for reliable gas detection in extreme heat, mitigating the risk of explosions and ensuring operational safety in highly specialized chemical processes.

3. Parameter:

Main Parameters Value/Description Product Model: Honeywell 2106B2311 Manufacturer: Honeywell Analytics (part of Honeywell) Product Category: Fixed Point Gas Detector Sensor (Flammable) Associated Product Line: Honeywell Sensepoint High Temperature (HT) Combustible Gas Detector Series Sensor Type: Catalytic Pellistor (bead) Gas Types Detected: Combustible hydrocarbons (flammable gases) Detection Range: Typically 0-100% LEL (Lower Explosive Limit), configurable via control card/transmitter. Operating Temperature: -55°C to +150°C (-67°F to +302°F) Output Signal: mV bridge output (requires external control system/transmitter for 4-20mA or digital output) Supply Voltage: 2.9 V to 3.5 V bridge (at 200mA) – typically supplied by a compatible control card. Power Consumption: 700mW (0.7W at 200mA maximum) Response Speed (T90): Less than 10 seconds (for methane, typical) Operating Life: Greater than 5 years (typical) Storage Life: Typically, over 5 years in original sealed packaging in clean, stable conditions. Housing Material: Polyphenylene Sulphide (PPS) for the sensor body, with a stainless steel mesh filter. Ingress Protection: IP65 standard; IP66/67 with Weather Protection fitted. Thread Type: M25 (for mounting into approved hazardous area junction boxes) Approvals: ATEX, IECEx certified for hazardous areas. ATEX Certification Example: II 2 GD Ex d IIC Gb T3 Tamb -40ºC to +150ºC; Ex tb IIIC T200ºC Db IP66 A21 (Note: Specific marking may vary slightly depending on the exact certification document, but this reflects typical high-temp Ex d/Ex tb rating). Key Features: Poison-resistant catalytic beads, very stable baseline, fast response, low cost, disposable design for easy replacement.

4. Technical Principles and Innovative Values:

The Honeywell 2106B2311 Sensepoint HT Flammable Sensor leverages advanced technical principles and offers significant innovative value, particularly tailored for high-temperature and harsh conditions:

• Innovation Point 1: Advanced Poison-Resistant Catalytic Bead Technology: The sensor features Honeywell’s specially designed poison-resistant catalytic bead elements. The fundamental principle involves the catalytic oxidation of flammable gas on a heated bead, causing its resistance to change, which is then measured in an mV bridge circuit. The “poison-resistant” aspect is a critical innovation that allows the sensor to maintain its performance and longevity even in the presence of common industrial contaminants like silicones, chlorinated hydrocarbons, and sulfur compounds, which often degrade standard catalytic sensors. This ensures superior reliability and reduced false alarms or undetected gas events in complex industrial environments.
• Innovation Point 2: Unrivaled High-Temperature Operation with Stable Baseline: The “HT” (High Temperature) designation highlights its core innovative capability: reliable and accurate operation in extreme temperatures up to +150°C (+302°F). This is achieved through meticulous material selection and optimized thermal design, ensuring the sensor maintains a very stable baseline and accurate readings across its wide operational temperature range. This capability is paramount for safety monitoring in applications such as gas turbine enclosures, industrial drying ovens, and engine rooms, where standard sensors would quickly fail, thereby enabling continuous and robust protection where it’s most needed.
• Innovation Point 3: Cost-Effective and Simplified Maintenance through Disposable Design: The 2106B2311 is engineered as a sealed, disposable unit. This innovative design streamlines maintenance: instead of complex on-site recalibration or repair of individual sensing elements, the entire sensor unit can be quickly and easily replaced at the end of its typical 5+ year operational life or if contamination/damage occurs. This approach significantly reduces maintenance time, labor costs, and the need for specialized tools, providing a high-quality, low-cost solution for industrial gas monitoring while ensuring consistent performance over time.

5. Application Cases and Industry Value:

In a large automotive paint shop, forced-air drying ovens operate at high temperatures, and flammable solvent vapors are inherent to the painting process. Undetected accumulation of these vapors poses a severe explosion risk. The plant implemented Honeywell 2106B2311 Sensepoint HT Flammable Sensors (ATEX) M25 strategically within the oven chambers and exhaust ventilation systems, installed in appropriate high-temperature flameproof junction boxes. The sensors’ ability to function reliably at temperatures up to +150°C and their poison-resistant beads ensured accurate and stable monitoring despite the presence of solvent byproducts. Upon detection of solvent vapor concentrations approaching critical LEL levels, the system automatically triggered alarms, initiated emergency ventilation, and, if necessary, shut down the oven to prevent ignition. This direct solution addressed the critical pain point of effective gas detection in a high-temperature, explosive atmosphere, significantly enhancing worker safety, preventing costly production downtime due to explosions, and ensuring compliance with stringent safety regulations.

6. Related Product Combination Solutions:

The Honeywell 2106B2311 sensor is designed to be an integral part of a complete fixed gas detection system:

• Approved High-Temperature Hazardous Area Junction Box (e.g., Honeywell FEEL Exe J.Box 2052D0001): This is essential for housing the sensor, providing the necessary hazardous area certification (Ex d or Ex e), and facilitating safe electrical connections in high-temperature zones.
• Approved Hazardous Area Cable Glands: Required for safely routing external wiring into the junction box while maintaining the flameproof or increased safety integrity of the enclosure.
• Weather Protection (e.g., Honeywell 00780-A-0076): An optional but recommended accessory, especially for outdoor or wash-down areas, to protect the sensor from direct rain, dust, and UV exposure while maintaining its ingress protection rating (IP66/67).
• Gas Detection Controller/Transmitter (e.g., Honeywell XNX Universal Transmitter, Honeywell Touchpoint Plus, or a 3rd party DCS/PLC system with compatible mV input): This crucial component receives the raw mV bridge signal from the 2106B2311 sensor and converts it into a standard industry output (e.g., 4-20mA, Modbus). It also processes alarm conditions, provides local display and relays, and interfaces with the plant’s overall control system or Safety Instrumented System (SIS).
• Calibration Gas and Flow Regulator: Essential tools for periodic functional “bump tests” (to confirm sensor response) and full calibrations of the sensor to ensure its ongoing accuracy and compliance.
• Collecting Cone or Flow Adaptor: Optional accessories that can be fitted to the sensor for optimized detection of gases lighter than air or for use in sampling systems/ducts.