Catalytic Combustible : HW Sensor
Catalytic Combustion Method Sensor: HW used for detecting combustible gases. The sensor consists of a detector element and a compensation element, both placed within an alumina support. The detector element burns in reaction to any detectable gas, while the compensation element remains inactive against combustible gases. A precious-metal wire coil heats the detector element to between 300°C to 450°C, allowing it to recognize changes in resistance as voltage determines the concentration of the gas. The bridge circuit shown in the diagram allows the sensor to recognize the change in resistance as the voltage to determine the concentration of the gas. The sensor is widely used and is a high-sensitivity gas sensor for low concentrations.
New Ceramic : NC Sensor
The New Ceramic Catalytic Method Sensor: NC. a sensor that uses an ultra-atomized oxidant catalyst to detect a wide range of concentrations of combustible gas. The sensor consists of a detector element and a compensation element made from ceramic-based sensors. The detector element consists of a coil of precious-metal wire and ultra-atomized oxidant catalyst, while the compensation element consists of a coil of precious-metal wire and glass. The sensor is designed to detect gas in a wide range of concentrations from a low level (ppm) to the lower-explosion-limit (LEL). The precious-metal wire coil heats up when heated, and when combustible gas burns on the surface of the detector element, the temperature of the element increases. With changes in temperature, the precious-metal wire coil changes in resistance, which changes almost in proportion to the concentration of the gas. The bridge circuit shown in the diagram allows the sensor to recognize the change in resistance as the voltage to determine the concentration of the gas. The sensor is an epoch-making technology developed for detecting combustible gas.
Semi-Conductor: SG Sensor
A metal oxide semiconductor sensor that detects gases by measuring changes in resistance when it comes into contact with a detectable gas. The sensor is a general-purpose sensor that detects all types of gases ranging from toxic gases to combustible gases. The sensor consists of a heater coil and a metal oxide semiconductor (SnO2) formed on an alumina tube. The tube is equipped with two Au electrodes at its ends to measure the resistance of the semiconductor. The heater coil heats the surface of the metal oxide semiconductor to 350 to 400°C. With atmospheric oxygen adsorbed on this surface in forms of O²⁻and O²⁺, the semiconductor keeps constant resistance. Then, when a detectable gas such as methane comes into contact with the surface, it becomes oxidized by O²⁻ ions which is turn oxidized by O²⁺ ions separated. The reaction occurring on the surface of the sensor is represented as follows: CH₄ + 4O₂⁻ -> CO. The bridge circuit shown in the diagram allows the sensor to recognize the change in resistance as the voltage to determine the concentration of the gas. The sensor is a widely used gas sensor designed specifically for combustible gases.
Hot Wire Type Semi-Conductor: SH Sensor
Hot Wire Type Semi-Conductor Method Sensor: SH that uses a metal oxide semiconductor to detect changes in resistance when it comes into contact with detectable gases. The sensor is a high-sensitivity gas sensor for low concentrations and detects all types of gases ranging from toxic gases to combustible gases 1. The sensor consists of a detector element and a compensation element with inertial material sintered on detectable gases sintered on it. The detector element consists of a coil of precious-metal wire and metal oxide semiconductor sintered on the coil, while the compensation element consists of a coil of precious-metal wire and inertial material sintered on it. The bridge circuit shown in the diagram allows the sensor to recognize the change in resistance as the voltage to determine the concentration of the gas. The sensor is widely used and is a high-sensitivity gas sensor for low concentrations.
Thermal Conductivity Method Sensor: TE Sensor
A Thermal Conductivity Method Sensor: TE that detects differences in thermal conductivity to determine gas concentration, especially effective for high-concentration combustible gases. The sensor consists of a detector element and a compensation element. The detector and compensation elements are available in two types: one consists of a coil of platinum wire and a mixture of glass, while the other consists of a coil and an inactive metal or like coated over the coil. The detector element is designed to allow detectable gases to contact it, while the compensation element is enclosed so as not to allow any detectable gas to contact it. The platinum wire coil heats the detector element to 200°C to 500°C, allowing detectable gases to contact it. The change in temperature changes the resistance, which is detected by a bridge circuit determining gas concentration. The sensor is widely used and is a high-sensitivity gas sensor for low concentrations.
Potentiostatic Electrolysis: ES Sensor
Potentiostatic Electrolysis Method Sensor: ES that is used for detecting toxic gases. The sensor electrolyzes detectable gas using an electrode with the potential kept constant to allow current to be measurable, and then measures the current to determine the gas concentration. It is the gas sensor most suitable for detecting toxic gases, and you can specify a particular potential to detect a particular gas. The sensor is structured with an electrode (action electrode) – a gas-permeable film with catalyst (e.g., gold or platinum) placed over it – along with reference and counter electrodes; these components are housed in a plastic container filled with an electrolytic solution. The potentiostatic circuit shown in the diagram keeps the potential between action and reference electrodes constant . The sensor is widely used and is a high-sensitivity gas sensor for low concentrations .
Membrane-Separated Electrode: ES-K Sensor
A toxic gas sensor that uses the Membrane-Separated Electrode Method. The sensor is highly selective and is based on potentiostatic electrolysis, featuring a gas-permeable film and an action electrode that are separate. The sensor consists of an action electrode, metal electrode covered with a gas-permeable film placed over it along with a reference and counter electrodes; these components are housed in a plastic container filled with an electrolytic solution. The sensor detects toxic gases by electrolyzing detectable gas using an electrode with the potential kept constant to allow current to be measurable, and then measures the current to determine the gas concentration. The sensor is widely used and is a high-sensitivity gas sensor for low concentrations.
Membrane Type Galvanic Cell: OS Sensor
A Membrane Type Galvanic Cell Method Sensor used for detecting oxygen. The sensor is a traditional sensor that operates without an external power supply and maintains stability over the long term. The sensor consists of a cathode (precious metal) and an anode (lead) placed in an electrolytic solution with a separation membrane closely attached to the outside of the cathode. Oxygen passes through the separation membrane and gets reduced at the cathode, while simultaneously it becomes oxidized at the anode in the electrolytic solution. A current flows due to this reduction reaction, which is inverted into voltage by the resistor before being outputted from the terminal. The sensor output is proportional to oxygen concentration or partial pressure.
Non-Dispersive Infrared Method Sensor: DE Sensor
Non-Dispersive Infrared Method Sensor: DE used for detecting gases. The sensor is based on detecting changes caused by the absorption of detectable gases. The sensor is structured with an infrared light source, measurement cell, optical filter, and infrared sensor. When a detectable gas enters the measurement cell, it absorbs infrared light. This change in light amount helps determine gas concentration. The sensor output is proportional to gas concentration. The sensor is widely used and is a high-sensitivity gas sensor for low concentrations.
Interferometer Method Sensor: FI Sensor
A Interferometer Method Sensor: FI used for detecting gases. The sensor is one of the oldest gas sensors that recognizes changes in refractive index of gases with high accuracy. It is widely used to measure solvent concentrations or heat quantities of fuel gases such as natural gas. The sensor is structured with an infrared light source, measurement cell, optical filter, and infrared sensor. When a detectable gas enters the measurement cell, it absorbs infrared light. This change in light amount helps determine gas concentration. The sensor output is proportional to gas concentration. The sensor is a high-sensitivity gas sensor for low concentrations.