The majority of manufacturing and industrial processes involve chemicals and machinery that can cause a risk of high levels of poisonous or flammable gases. This can cause serious hazards to personnel involved, as well as those living nearby and on industrial property. For this reason, gas detection equipment plays a vital role in any manufacturing or industrial environment and must be regarded with utmost importance to avoid injury, damage, downtime or - worst of all - loss of life.

In this article, we take a look at what gas sensors are, how they work, and their applications in industrial safety.

 

What are gas sensors?

Gas sensors, also referred to as gas detectors, are electronic devices that are used to detect and identify different types of gases in the environment. They are often installed to detect toxic or explosive gases and leaks in factories and manufacturing facilities. They come in various different sizes and can be portable or fixed. 

When choosing a gas sensor, it’s important to be aware of the different ranges and sensing abilities to ensure it is appropriate for your facility. They often form part of a wider system, such as a hazmat or security system, and are connected to an alarm to notify those involved. Gas sensors require regular calibration as they are constantly interacting with air and other less harmful gases in the environment. 

In industrial facilities, gas detectors are used to protect the health and safety of personnel involved and property while ensuring industrial process integrity. Industry workers are becoming increasingly aware of the importance of this piece of equipment and are seeking reliable solutions that are cost effective and robust. 

Common types of gas sensors include electrochemical gas sensors, catalytic combustion gas sensors, semiconductor gas sensors, and infrared gas sensors (all of which we will look at in more detail later on). Different sensors are suited to different environments, and offer various performance metrics, gas detection abilities and applicability.

 

Gas sensor properties

Here are the fundamental gas sensor properties to consider when looking for a solution for your industrial facility. These basic characteristics are mainly determined by the materials the sensor is constructed from. 

 

1. Stability

This refers to the basic response stability of the sensor when it is operational. This will depend on the zero and interval drift levels, with the former referring to the change in sensor output when there is no gas present and the latter to the change in output response when there is gas present.

 

2. Sensitivity

Sensitivity relates to the ratio of output change to input change of the sensor. This will depend on the technology that’s used in the structure of the sensor. The sensitivity must be sufficient for the detection of the threshold limit value or lower explosive limit for optimal performance.

 

3. Selectivity

Also referred to as cross-sensitivity, this is determined by measuring the sensor response that’s caused by a specified concentration of interfering gas. This is extremely important when tracking multiple gases as it can reduce the repeatability of the measurement, so the best sensors have high sensitivity and selectivity to ensure optimal detection.

 

4. Corrosion Resistance

This refers to how resistant the sensor is when exposed to a high volume fraction of gas. The sensor should be able to withstand high gas volume fraction and the drift and correction values should be minimal.

 

Types of gas sensor

Here’s an overview of the main types of gas sensors that are employed in industrial environments.

 

1. Electrochemical Gas Sensors

Electrochemical gas detectors work by measuring a specific type of gas’s concentration through oxidising the gas to an electrode. The result of this is to generate a positive or negative current flow. This is one of the most common types of gas sensor and is typically used to measure target gas concentration in an external circuit.

 

2. Catalytic Bead Sensors

Catalytic gas detectors measure combustible gases that are involved in an explosion hazard when concentrations lie between the lower and upper explosion limits. These function based on the principle that when a gas oxidises it produces heat, so the sensor converts the temperature change.

 

3. Infrared Gas Sensors

 Infrared gas sensors are implemented in environments where there is no oxygen present or where it is required to measure high carbon dioxide concentrations. These function using principles of light absorption where the change in absorbed light intensity can be measured relative to that at a reference wavelength. It calculates the difference in absorbed light and computes the gas concentration.

 

4. Photoionization Gas Sensors

This type of gas detector relies on an ultraviolet light to ionise gases to positive and negative ions. These can then be identified with the detector.

 

Applications in industrial environments

There are various reasons gas detectors are applied in industrial environments. Here are three of the key motives. 

Safety 

One of the top priorities for industrial environments and manufacturing facilities is ensuring the safety of workers. Gas detection solutions play an integral role in safety and hazard mitigation in environments where danger is present. This piece of equipment is designed to monitor and measure gas concentrations to alert personnel to any danger caused by high levels.

 

Harsh environments

In particularly harsh environments, gas detectors offer protection in the presence of harsh gases that are commonly present in industrial processes. The gas sensor must be able to withstand these harsh conditions itself, so it’s important to ensure the solution you choose is durable and suitable for the environment in which it is being installed.

 

Indoor air quality/HVAC applications

In many indoor air quality and HVAC applications, gas sensor technologies play an important role in monitoring air quality in a range of environments and indoor enclosed environments including homes, offices and facilities. They can deliver early detection of increased CO2 levels and help to support energy efficiency initiatives. This can help to improve the health and cognitive abilities of occupants while also minimising the risk of airborne disease transmission.

 

Discover the range of gas sensor components from Preferred Spares

As one of the leading industrial automation equipment and spare parts providers in the Middle East, Preferred Spares offers a range of components for gas sensors from the world’s leading manufacturers. Among these are a range of evaluation modules and sockets, such as the EM26 Evaluation Module for TGS26-series Sensors from Figaro, which are key components in gas sensors. 

 

Browse the full range of industrial safety equipment that includes scanners, sensors and coders from one the leading electrical equipment suppliers for the Middle and East and the world.