Riken Keiki GD-D58-AC Suction Gas Detector Head

RIKEN KEIKI GD-D58-AC Suction Type Combustible Gas Detector Head

The Riken Keiki GD-D58-AC is a heavy-duty, fixed sample-drawing (suction type) combustible gas detector head engineered for continuous atmospheric monitoring in hazardous marine, offshore, and industrial environments. Designed specifically for installations where diffusion-style detectors cannot access confined or hazardous sample points, the GD-D58-AC features an integrated explosion-proof suction pump mechanism that draws sample gases across distances through dedicated tubing directly to the sensing element.

Operating on an AC power line supply (100–110 VAC, 50/60 Hz), this detector head utilizes either a catalytic combustion or new ceramic detection principle to deliver fast, highly accurate, and linear sensor-direct voltage output to compatible central indicator/alarm units. Housed in a rugged, marine-grade cast aluminum flameproof enclosure rated Ex d IIB + H2 T4 and IP67, the GD-D58-AC ensures reliable gas monitoring in pump rooms, cargo holds, ducting, compressor rooms, and industrial processing skids.

Model Details

• Manufacturer: Riken Keiki Co., Ltd. (Japan)
• Base Model Series: GD-D58 Series
• Full Model Designation: GD-D58-AC (Sample Drawing Type / AC Line Powered)
• Manufacturer Part Number (MPN): GD-D58-AC-GP
• Internal Pump Assembly: Integrated RP-D58 Series explosion-proof sampling pump
• Housing Finish: Polyurethane coating, Munsell 7.5BG5/2

Technical Specifications: Riken Keiki GD-D58-AC

Key Features

1. Flameproof & Hydrogen-Rated Enclosure: Certified explosion-proof to Ex d IIB + H2 T4, allowing safe deployment in hazardous zones with flammable hydrocarbon and hydrogen vapor risks.
2. Direct Sensor Output Architecture: Transmits raw millivolt/bridge sensor signals directly to central alarm and monitoring units without intermediate signal latency.
3. Built-In Flow Rate Self-Diagnosis: Employs an internal low-flow monitoring sensor that triggers an auto-resetting, non-latching fault alarm when line flow falls below critical sampling thresholds.
4. Plug-In Sensor Module System: Utilizes pre-calibrated plug-in replacement sensors and modular flow blocks to minimize downtime during scheduled dry-dock or operational maintenance.

System Compatibility & Integration

• The GD-D58-AC is designed for seamless integration with industrial and marine multi-channel monitoring consoles, including:
• Riken Keiki Indicator / Alarm Units: GP-591, GP-671, GP-571A, EC-592, RM-5000 Series, and BL-7000 centralized gas alarm systems.
• Marine Automation / AMS: Compatible with major marine Alarm Monitoring Systems (Kongsberg K-Chief, Lyngsø Marine, Wärtsilä, Nabtesco, Yokogawa Centum) when interfaced via appropriate Riken Keiki signal converter modules.
• Sampling Accessories Compatibility: Compatible with external spiral drain separators, water dust filters (CF-65, CF-83), flame arresters, and flow meters.

Industrial Applications

• Marine Oil & Chemical Tankers: Continuous hydrocarbon vapor monitoring in ballast pump rooms, cofferdams, pipe tunnels, double bottoms, and inert gas header systems.
• LNG / LPG Gas Carriers: Gas detection inside compressor rooms, boil-off gas handling rooms, cargo machinery spaces, and airlock passages.
• Offshore Platforms & FPSOs: Sample monitoring of production skids, wellhead enclosures, and enclosed process modules.
• Petrochemical Refineries & Storage Facilities: Sampling combustible gases in valve manifolds, boundary perimeters, and pipeline trench networks.
• Thermal & Gas-Fired Power Plants: Continuous monitoring around fuel gas conditioning stations and turbine enclosures.

Frequently Asked Questions

What is the difference between the Riken Keiki GD-D58-AC and SD-D58-AC?

The GD-D58-AC is a blind detector head that sends direct sensor outputs to a centralized remote control unit. The SD-D58-AC includes a built-in local digital concentration display and direct optical maintenance switches on the front cover.

What supply voltage is required for the GD-D58-AC model?

The GD-D58-AC requires an input voltage of 100 to 110 VAC at 50/60 Hz with a maximum power consumption of 13 VA. For 24 VDC installations, the GD-D58-DC model must be specified.

Can the GD-D58-AC detect gases in inerted or oxygen-depleted atmospheres?

Because the GD-D58-AC utilizes catalytic combustion and new ceramic sensing elements that require atmospheric oxygen to oxidize combustible gases, it cannot directly measure hydrocarbons in fully inerted tanks (e.g., nitrogen or flue gas blanketed). An infrared-based detector (such as the Riken Keiki RI series) is recommended for zero-oxygen environments.

How often should zero and span calibration be conducted?

Under SOLAS and standard marine classification guidelines, gas detection systems must undergo operational zero and span verification at least once every six months using certified span gas cylinders (e.g., Iso-butane, Methane, or Propane in air balance).