Point Gas Detector Spectrex Rosemount 625IR
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Point Gas Detector Spectrex Rosemount 625IR

The Rosemount 625IR is an optical infrared gas detector designed for continuous monitoring of combustible gases in demanding industrial applications. The device uses dual-wavelength optical absorption technology and temperature-compensated solid-state IR sensing to provide accurate measurement of target gas concentrations.

The detector is factory-configured for methane or propane with a measuring range of 0–100% Lower Explosive Limit (LEL). Factory calibration is maintained throughout the detector’s lifetime, eliminating the need for field recalibration.

Rosemount 625IR provides real-time gas concentration and device status information. The T90 response time is less than one second without the environmental protection accessory and approximately two seconds when the protection is installed.

Heated optics help prevent moisture accumulation on the optical surfaces, while continuous self-diagnostics monitor all critical operating functions. The detector is available as a standalone version or as a duct-mounted version with either a 15 cm or 35 cm insertion probe.

Typical applications include:

  • Offshore and onshore process facilities
  • Oil and gas pipelines
  • FPSO and FLNG installations
  • Chemical and petrochemical plants
  • Power generation facilities
  • Refineries
  • Tank farms and loading terminals
  • Gas filling and distribution terminals
  • Gas transmission and pipeline networks
  • Hazardous areas where hydrocarbon gases may be present

Benefits:

  • No field calibration required
    Factory calibration is maintained throughout the detector’s service life. The system continuously verifies the IR source and receiver and automatically performs any required compensation.
  • Ultra-fast response time
    Rosemount 625IR provides a T90 response time of less than one second without the environmental protection accessory and approximately two seconds with it installed.
  • High accuracy and stability
    The detector delivers an accuracy of ±2% of full scale with ±1% repeatability and no zero or span drift.
  • Heated optics
    The integrated heating system minimizes condensation on the optical surfaces, ensuring reliable performance in harsh environments.
  • Continuous self-diagnostics
    Critical functions are continuously monitored, while a multicolor front LED provides clear visual indication of detector status.
  • Extended proof test interval
    A recommended five-year proof test interval helps reduce maintenance requirements and operating costs.
  • Gas-free functional testing
    Optional accessories allow functional testing without the use of calibration gas.
  • Easy industrial integration
    The detector supports 4–20 mA analog output, HART communication, and RS-485 Modbus RTU.
  • Functional safety certified
    Rosemount 625IR is SIL 2 certified and available with approvals for installation in hazardous locations.

Available Versions

Rosemount 625IR – Standalone Version

The standard version is designed for direct installation in hazardous areas where continuous combustible gas monitoring is required.

Main features:

  • 0–100% LEL measurement range
  • Factory configured for methane or propane
  • ¾-inch NPT threaded connection
  • 316 stainless steel housing
  • Approximate weight: 3.75 kg

Rosemount 625IR – Duct Mount Version with 15 cm Probe

Designed for gas monitoring inside ducts and ventilation systems.

Main features:

  • 15 cm insertion probe
  • 0–100% LEL measurement range
  • Approximate weight: 4.0 kg
  • Dedicated flange mounting and testing accessories available

Rosemount 625IR – Duct Mount Version with 35 cm Probe

Designed for applications requiring deeper insertion into ducts or pipelines.

Main features:

  • 35 cm insertion probe
  • 0–100% LEL measurement range
  • Approximate weight: 4.25 kg

Compatible with duct mounting kits

Descriere

Technical Specifications:

Feature Value
Product type Point gas detector with optical IR technology
Detection principle Dual-wavelength optical absorption
Technology Temperature-compensated solid-state IR sensing
Configurable gases Methane or propane
Measurement range 0–100% LEL
Calibration Factory calibrated; no field calibration required
Accuracy ±2% of full scale
Repeatability ±1% of full scale
Response time T90 <1 s without environmental protection; T90 = 2 s with environmental protection
Drift No zero or span drift
Start-up time Less than 2 minutes above −20°C; less than 20 minutes below −20°C
Operating temperature −40°C to +75°C
Storage temperature −40°C to +75°C
Relative humidity 0–99% RH
Supply voltage 18–32 VDC
Power consumption Less than 3 W (standard version); less than 5 W (Arctic version)
Inrush current Limited to 1 A
Analog output 4–20 mA (source or sink)
Digital communication HART
Serial communication RS-485, Modbus RTU
Status indication Multicolor front LED
Self-diagnostics Continuous automatic self-monitoring
Housing material 316 stainless steel
Cable entry ¾-inch NPT
Maximum conductor size 2.5 mm² stranded; 4 mm² solid
Protection rating IP66, IP67, NEMA 4X
Mounting options Standalone or duct-mounted with 15 cm or 35 cm probe
Weight – standalone version 3.75 kg
Weight – 15 cm probe version 4.0 kg
Weight – 35 cm probe version 4.25 kg
Proof test interval 5 years
Functional safety SIL 2 (IEC 61508)
Hazardous area certifications ATEX, IECEx, FM (US & Canada), depending on configuration
Product warranty 5-year limited warranty
IR source warranty 15 years

Available Accessories

A complete range of accessories is available for installation, protection, and functional testing, including:

  • Gas-free methane functional tester (50% LEL)
  • 2-inch pole mounting kit
  • 3-inch and 4-inch pole mounting kits
  • Weather sunshield
  • Insect screen
  • Maintenance lockout kit
  • Aspirator kit
  • Remote bump test kit
  • Bump test enclosure
  • Environmental protection assembly
  • Environmental protection cap
  • Gas test nozzle
  • Duct mounting flange kits
  • Duct-mounted detector testing kit

Consulting & Quotation

Looking for a point gas detector configured for your application?

The instrumentatie.ro team can assist you with:

  • gas selection and factory configuration
  • choosing between standalone and duct-mounted versions
  • output and communication configuration
  • hazardous area certification selection
  • mounting and testing accessories
  • integration into PLC, DCS, SCADA, and safety systems

📧 office@instrumentatie.ro

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