Riken Keiki SD-3 Fixed Gas Detector with Signal Converter

Overview

Riken Keiki SD-3 Fixed Gas Detector with Signal Converter | Intelligent Fixed Gas Detection System for Combustible, Toxic Gases & Oxygen

The Riken Keiki SD-3 Fixed Gas Detector with Signal Converter is a next-generation intelligent fixed gas detection system designed for continuous monitoring of combustible gases, toxic gases, oxygen (O₂), and selected process gases in hazardous industrial environments. Manufactured by Riken Keiki Co., Ltd., Japan, the SD-3 combines advanced sensing technology, a built-in signal converter, flexible installation options, and global safety certifications to deliver reliable gas detection for critical industrial applications.

Designed to meet the evolving requirements of modern industrial safety systems, the SD-3 provides accurate gas concentration measurement while offering seamless integration with PLC, DCS, SCADA, Fire & Gas Systems, Building Management Systems (BMS), and Emergency Shutdown Systems (ESD). Its built-in signal converter simplifies installation by converting sensor signals directly into industry-standard outputs, reducing wiring complexity and lowering installation costs.

The Riken Keiki SD-3 supports multiple sensor technologies through the F Sensor Series, allowing users to monitor a wide variety of combustible gases, toxic gases, and oxygen using a single detector platform. Depending on the selected sensor, the detector can monitor methane, hydrogen, carbon monoxide, hydrogen sulphide, ammonia, oxygen, refrigerant gases, and numerous industrial process gases with excellent accuracy and stability.

One of the major strengths of the SD-3 is its modular design, allowing easy sensor replacement and simplified maintenance. This minimizes production downtime while improving operational efficiency. The detector also supports various installation methods, including diffusion type, suction type, duct mounting, and remote sensor configurations, enabling it to adapt to different industrial environments and process requirements.

The integrated signal converter supports 4–20 mA analog output with HART® communication as standard, while selected models also offer Modbus RS-485 communication and programmable relay outputs. These communication capabilities enable easy integration into plant automation systems, allowing operators to monitor gas concentrations in real time and respond quickly to hazardous conditions.

Built for harsh industrial environments, the SD-3 features a rugged aluminium enclosure with IP66/IP67 protection, providing excellent resistance against dust, water, vibration, and corrosion. The detector is approved to major international safety standards including IECEx, ATEX, FM, CE, and SIL 2, making it suitable for installation in hazardous areas across marine, offshore, oil & gas, petrochemical, hydrogen, chemical, and industrial facilities worldwide.

The detector is widely used for protecting personnel, equipment, and production processes in applications where continuous gas monitoring is essential. Whether installed on offshore platforms, LNG terminals, hydrogen production facilities, oil refineries, chemical plants, marine vessels, power stations, or industrial manufacturing plants, the Riken Keiki SD-3 delivers dependable long-term performance with minimal maintenance requirements.

Combining Japanese engineering excellence, intelligent electronics, versatile communication, and proven gas sensing technologies, the Riken Keiki SD-3 Fixed Gas Detector with Signal Converter is an ideal solution for industrial facilities seeking reliable, accurate, and future-ready fixed gas detection.

Key Features of Riken Keiki SD-3 Fixed Gas Detector

The Riken Keiki SD-3 combines intelligent sensing technology, flexible communication, and rugged industrial construction for reliable continuous gas monitoring.

Built-In Signal Converter

The SD-3 features an integrated signal converter that simplifies installation and improves compatibility with industrial automation systems.

Benefits

• Simplified wiring

• Reduced installation costs

• Stable signal transmission

• Reliable industrial communication

• Easy system integration

Supports Multiple Gas Types

The detector is available for monitoring numerous industrial gases.

Typical detectable gases include:

• Methane

• Hydrogen

• Carbon Monoxide (CO)

• Hydrogen Sulphide (H₂S)

• Oxygen (O₂)

• Ammonia (NH₃)

• Refrigerant Gases

• Combustible Hydrocarbon Gases

• Toxic Industrial Gases

Advanced F Sensor Series

The SD-3 utilizes Riken Keiki's advanced F Sensor Series, providing excellent measurement accuracy and long-term stability.

Advantages

• Fast response time

• High sensitivity

• Excellent repeatability

• Long sensor life

• Stable performance

Flexible Installation Options

The detector supports multiple installation methods for different applications.

Available configurations include:

• Diffusion Type

• Suction Type

• Duct Mount

• Remote Sensor Installation

This flexibility allows installation in a wide range of industrial environments.

Industrial Communication

The SD-3 integrates easily with industrial safety systems.

Standard communication includes:

• 4–20 mA Analog Output

• HART® Communication

Optional:

• Modbus RS-485

These interfaces allow easy integration with:

• PLC Systems

• DCS Platforms

• SCADA Systems

• Fire & Gas Systems

• Building Management Systems (BMS)

Rugged Industrial Housing

Designed for hazardous environments, the SD-3 features a durable enclosure offering:

• IP66/IP67 Protection

• Dust Resistance

• Water Resistance

• Corrosion Resistance

• Long Service Life

Global Safety Certifications

The detector complies with internationally recognized hazardous area standards.

Typical certifications include:

• IECEx

• ATEX

• FM

• CE

• SIL 2

These certifications make the SD-3 suitable for use in hazardous industrial locations worldwide.

Benefits of Riken Keiki SD-3 Fixed Gas Detector

Key Benefits

• Built-in signal converter

• Multiple gas detection capability

• Advanced F Sensor Series

• High measurement accuracy

• Fast response time

• Flexible installation options

• HART® communication

• Optional Modbus communication

• Easy PLC & SCADA integration

• Rugged IP66/IP67 enclosure

• International hazardous area approvals

• Reliable Japanese engineering

• Low maintenance requirements

Why Choose Riken Keiki SD-3?

The Riken Keiki SD-3 Fixed Gas Detector with Signal Converter is designed for industrial facilities that require accurate, reliable, and flexible gas monitoring. Its built-in signal converter simplifies installation, while multiple sensor options allow monitoring of combustible gases, toxic gases, oxygen, and specialty gases using a single platform.

The detector's advanced communication capabilities, rugged construction, and international certifications make it suitable for demanding environments including offshore platforms, marine vessels, hydrogen facilities, oil refineries, chemical plants, and industrial manufacturing sites. Combined with Riken Keiki's reputation for precision and reliability, the SD-3 provides a dependable long-term solution for industrial gas safety.

Working Principle

The Riken Keiki SD-3 continuously monitors gas concentrations using the appropriate sensing technology selected for the target gas. The detector converts the sensor signal through its integrated signal converter into standard industrial outputs such as 4–20 mA and HART®, enabling seamless communication with plant control systems.

When gas concentrations exceed preset alarm thresholds, the detector activates alarm outputs and transmits signals to connected PLC, DCS, SCADA, or Fire & Gas systems, allowing immediate corrective action to protect personnel and equipment.

Typical Applications

The Riken Keiki SD-3 is widely used in:

Marine & Shipping

• Engine Rooms

• Pump Rooms

• Cargo Areas

• LNG Carriers

• Oil Tankers

Offshore Oil & Gas

• Offshore Platforms

• FPSOs

• Drilling Rigs

• Compressor Stations

• Production Facilities

Petrochemical Industry

• Oil Refineries

• Chemical Plants

• Tank Farms

• Solvent Storage Areas

Hydrogen Industry

• Hydrogen Production Plants

• Hydrogen Refuelling Stations

• Fuel Cell Manufacturing

• Hydrogen Storage Facilities

Industrial Applications

• Power Generation Plants

• Pharmaceutical Manufacturing

• Water Treatment Plants

• Food Processing Facilities

• Manufacturing Plants

• Utility Facilities

Detection Technologies

The Riken Keiki SD-3 supports multiple sensing technologies to provide accurate monitoring of combustible gases, toxic gases, oxygen, and specialty gases.

Catalytic Combustion Sensor

Designed for combustible gas detection.

Typical detectable gases include:

• Methane (CH₄)

• Hydrogen (H₂)

• Propane

• Butane

• LPG

• Natural Gas

Benefits

• Fast response

• Stable performance

• Reliable LEL monitoring

• Proven industrial technology

Electrochemical Sensor

Used for toxic gas monitoring.

Typical gases include:

• Carbon Monoxide (CO)

• Hydrogen Sulphide (H₂S)

• Ammonia (NH₃)

• Chlorine (Cl₂)

• Sulphur Dioxide (SO₂)

• Nitrogen Dioxide (NO₂)

• Hydrogen Cyanide (HCN)

Advantages

• High sensitivity

• Excellent selectivity

• Accurate measurement

• Low power consumption

Galvanic Cell Sensor

Designed for oxygen monitoring.

Benefits include:

• Accurate oxygen measurement

• Long operational life

• Stable output

• Fast response

Semiconductor Sensor

Suitable for selected combustible and specialty gases.

Advantages:

• High sensitivity

• Long sensor life

• Reliable continuous monitoring

Infrared (NDIR) Sensor

Available for selected combustible and refrigerant gases.

Typical gases:

• Carbon Dioxide (CO₂)

• Hydrocarbon Vapours

• Refrigerant Gases

Benefits:

• No catalyst poisoning

• Long sensor life

• Stable measurement

• Low maintenance

Gas Types Detected

Depending on the installed sensor, the SD-3 supports monitoring of numerous industrial gases.

Combustible Gases

• Methane (CH₄)

• Hydrogen (H₂)

• Propane

• Butane

• LPG

• LNG Vapours

• Natural Gas

• Ethane

Toxic Gases

• Carbon Monoxide (CO)

• Hydrogen Sulphide (H₂S)

• Ammonia (NH₃)

• Chlorine (Cl₂)

• Sulphur Dioxide (SO₂)

• Nitrogen Dioxide (NO₂)

• Hydrogen Chloride (HCl)

• Hydrogen Cyanide (HCN)

Oxygen

• Oxygen (O₂)

Refrigerant & Specialty Gases

Selected models are available for monitoring refrigerant and specialty process gases used in industrial applications.

Measuring Ranges

Typical measuring ranges include:

Combustible Gases

• 0–100% LEL

Oxygen

• 0–25 Vol%

Carbon Monoxide

• 0–500 ppm

• 0–1,000 ppm

Hydrogen Sulphide

• 0–100 ppm

Ammonia

• Model Dependent

Refrigerant Gases

• Model Dependent

Note: Measuring ranges vary depending on the selected sensor and target gas.

Communication & Outputs

The SD-3 is designed for easy integration into industrial automation systems.

Standard Communication

• 4–20 mA Analog Output

• HART® Communication

Optional Communication

• Modbus RS-485

Relay Outputs

Depending on the model:

• High Alarm Relay

• Low Alarm Relay

• Fault Relay

Compatible Systems

The detector integrates with:

• PLC Systems

• DCS Platforms

• SCADA Systems

• Fire & Gas Systems

• Building Management Systems (BMS)

• Emergency Shutdown Systems (ESD)

F Sensor Series Features

The SD-3 utilizes Riken Keiki's advanced F Sensor Series, offering excellent performance and simplified maintenance.

Features

• High measurement accuracy

• Long sensor life

• Excellent stability

• Fast response

• Reliable long-term operation

• Easy sensor replacement

• Reduced maintenance costs

Installation Features

The SD-3 is designed for flexible installation across a wide range of industrial applications.

Supported installation methods include:

• Diffusion Type

• Suction Type

• Remote Sensor Installation

• Duct Mount Installation

Additional features:

• Compact design

• Simple wiring

• Front-access maintenance

• Flexible mounting options

• Easy commissioning

Industries Served

The Riken Keiki SD-3 is widely used in:

Marine Industry

• Cargo Ships

• LNG Carriers

• Oil Tankers

• Engine Rooms

• Pump Rooms

Offshore Oil & Gas

• Offshore Platforms

• FPSOs

• Drilling Rigs

• Production Facilities

• Compressor Stations

Petrochemical Industry

• Oil Refineries

• Chemical Plants

• Tank Farms

• Solvent Storage

Hydrogen Industry

• Hydrogen Production Plants

• Hydrogen Refuelling Stations

• Fuel Cell Manufacturing

• Hydrogen Storage Facilities

Industrial Applications

• Pharmaceutical Manufacturing

• Food Processing

• Water Treatment Plants

• Utility Plants

• Manufacturing Facilities

• Power Generation

Certifications & Compliance

The Riken Keiki SD-3 complies with major international industrial safety standards.

Typical certifications include:

• IECEx

• ATEX

• FM Approval

• CE Marking

• SIL 2 (Selected Models)

These certifications allow installation in hazardous industrial environments worldwide.