1. Description:

The Honeywell 2104B2071 is a Short Range Transmitter unit for the Honeywell Searchline Excel Infrared (IR) Open Path Flammable Gas Detector. This is a highly specialized safety device designed for continuous, non-contact detection of combustible hydrocarbon gases (such as methane, ethane, propane, butane, ethylene, etc.) in a wide area. Unlike point detectors, an open path system consists of a transmitter (2104B2071) that emits an infrared beam and a separate receiver unit (e.g., 2104B2070 or similar) that detects the beam. When flammable gas is present in the path, it absorbs some of the infrared light, and the receiver measures this absorption to determine the gas concentration over the entire path. This particular model is for “short range” applications, typically covering path lengths from 5 to 40 meters (15 to 130 feet). It is built with a robust stainless steel housing and uses a Xenon flash tube as its infrared source, ensuring high immunity to environmental interferences.

2. Application Scenarios:

Consider a large liquefied natural gas (LNG) storage terminal, where vast outdoor areas contain numerous storage tanks, pipelines, and loading/unloading facilities. The risk of large-scale flammable gas leaks is a critical concern, and traditional point detectors might not provide sufficient coverage for such expansive areas. The Honeywell 2104B2071 Searchline Excel Short Range Transmitter, paired with its corresponding receiver, would be strategically deployed across these open areas. Multiple transmitter-receiver pairs would create an invisible “fence” or “grid” of infrared beams around and within the critical zones. If a gas cloud forms and drifts into the path of a beam, the system immediately detects the presence and concentration of the flammable gas across the entire path. This provides rapid, wide-area detection, indicating the size of the hazard. This directly addresses the pain points of inadequate coverage and slow response times associated with traditional point detectors in large, open environments, significantly enhancing safety and enabling faster emergency response in the event of a leak.

3. Parameter:

Main Parameters Value/Description Product Model: Honeywell 2104B2071 Manufacturer: Honeywell Analytics (part of Honeywell) Product Category: Open Path Infrared Flammable Gas Detector – Transmitter Unit Associated Product: Honeywell Searchline Excel Open Path Gas Detector System Function: Emits an infrared beam for gas detection Gas Types Detected: Hydrocarbons (Methane, Ethane, Propane, Butane, Pentane, Ethylene, Propylene, Ethanol, Methanol) Detection Range: 0 to 5 LEL.m (Lower Explosive Limit per meter) Path Length (Short Range): 5 to 40 meters (15 to 130 feet) Light Source: Xenon flash lamp Output Signal: Part of a system that typically outputs 4-20mA analog signal or Modbus RS485 (via termination unit) Supply Voltage: 18V to 32V DC, 10W Max Response Speed (T90): Less than 3 seconds (under normal operating conditions) Operating Temperature: -40°C to +65°C (-40°F to 150°F) Operating Humidity: 0 to 99% RH (non-condensing) Housing Material: 316 Stainless Steel Ingress Protection: IP66 and IP67 Approvals: ATEX, IECEx, UL, FM/CSA (for hazardous areas), etc. (specific to product variant) Immunity: 100% immune to sunlight and other radiation sources (flare stacks, arc welding, lightning) Features: Contamination resistant optics, integral functional gas test facility.

4. Technical Principles and Innovative Values:

The Honeywell 2104B2071 Searchline Excel Short Range Transmitter embodies sophisticated technical principles and offers significant innovative value:

• Innovation Point 1: Patented Dual-Beam Infrared Absorption Spectroscopy: The core principle involves the transmitter emitting two specific infrared wavelengths: one at a reference wavelength that is not absorbed by the target gas, and another at a measurement wavelength that is absorbed by the target gas. By comparing the amount of light received at both wavelengths, the system can precisely determine the concentration of the gas in the path. This dual-wavelength approach provides excellent specificity and compensates for environmental factors like fog, rain, and dust.
• Innovation Point 2: Xenon Flash Lamp for Superior Solar Immunity: The use of a Xenon flash lamp as the infrared source is a key innovation. This lamp is designed to be significantly brighter than the sun at the detection wavelengths, allowing the detector to “overpower” sunlight interference. Combined with a unique pulse duration and shape, this technology ensures the system’s reliability and accuracy, even in direct sunlight or near other strong IR sources like flare stacks, which is a major advantage over other IR detection methods.
• Innovation Point 3: Wide Area Coverage with Quantitative Measurement: Unlike point detectors that only measure gas at a single location, the Searchline Excel system (with the 2104B2071 transmitter) provides continuous, wide-area volumetric detection. It measures the integrated gas concentration over the entire path length (LEL.m), giving a more comprehensive understanding of potential leak size and direction. This early warning capability for large, dispersing gas clouds is a critical safety innovation for industrial sites.

5. Application Cases and Industry Value:

In a large offshore oil platform, the risk of hydrocarbon gas leaks around wellheads, processing modules, and flare stacks is constant. The expansive and complex nature of the platform makes traditional point detection challenging and costly to implement comprehensively. By integrating the Honeywell 2104B2071 Searchline Excel Short Range Transmitter units across critical areas, paired with their receivers, the platform established a robust open-path gas detection network. These units provided continuous, real-time monitoring of hydrocarbon concentrations over wide areas. If a gas leak occurred, the system rapidly detected it, even before it reached a high concentration at a single point, providing a quicker alert to the control room. This early and comprehensive detection capability directly enhanced personnel safety, allowed for faster implementation of emergency procedures, and minimized the risk of explosions. The system’s immunity to harsh offshore weather conditions and sunlight further ensured reliable operation, significantly increasing the overall safety and operational integrity of the offshore asset.

6. Related Product Combination Solutions:

The Honeywell 2104B2071 is an integral part of the Honeywell Searchline Excel Open Path Gas Detection system:

• Honeywell Searchline Excel Receiver Unit (e.g., 2104B2070 or similar): This unit is mounted opposite the 2104B2071 transmitter and detects the infrared beam. It contains the optical detectors and signal processing electronics.
• Honeywell Searchline Excel Termination Unit (e.g., DX100, DVC100): This unit provides convenient field wiring connections, power supply, and typically converts the internal signal into an industry-standard 4-20mA analog output and/or Modbus RS485 digital output for integration with a plant’s Distributed Control System (DCS) or PLC.
• Handheld Interrogator (e.g., 2104N2999): A portable tool used for commissioning, alignment, calibration, and maintenance of the Searchline Excel system.
• Mounting Brackets and Alignment Kits: Essential for proper installation and alignment of the transmitter and receiver units.
• Calibration Gas and Gassing Cells: Used to perform functional gas tests and calibrate the system periodically.
• DCS/PLC System: Receives the 4-20mA or Modbus data from the Searchline Excel system for alarm management, data logging, and integration into the plant’s safety instrumented system (SIS).

7. Installation, Maintenance, and Full-Cycle Support:

Installation of the Honeywell 2104B2071 involves securely mounting the transmitter unit (and its corresponding receiver) at opposite ends of the desired monitoring path. Careful alignment of the transmitter’s infrared beam with the receiver’s optics is critical for optimal performance. This is typically done using an alignment kit that may include a telescope and handheld interrogator. Power (18-32VDC) and communication wiring connect to a termination unit, which then interfaces with the plant’s control system. Due to its hazardous area certifications, all wiring and installation must comply with local and national electrical codes for explosive atmospheres (e.g., ATEX, UL, CSA requirements).

Routine maintenance for the Searchline Excel system is designed to be minimal. The contamination-resistant optics and heated windows reduce the need for unscheduled cleaning. Periodic functional gas tests using a gassing cell and certified test gas are recommended to verify the system’s response. The integral self-diagnostics and fault-finding facilities aid in troubleshooting. As Honeywell is a leading global manufacturer of gas detection systems, comprehensive full-cycle support is readily available. This includes detailed product manuals, technical support from factory-trained engineers, calibration services, and access to genuine spare parts through a worldwide network of authorized distributors. This robust support ensures the long-term reliability and safety performance of the Searchline Excel system in critical industrial environments.