The Differences between a pellistor and an IR sensor

The Differences between a pellistor and an IR sensor

Sensors play an important role in monitoring flammable gases and vapours. Different factors should be considered while choosing the most appropriate technology for your requirements, such as the response time, pressure and temperature range, and the environment while adopting the sensors.

A pellistor sensor is quite different from an IR sensor, in terms of the advantages, disadvantages, features, and applications. These aspects should be evaluated in-depth to make sure you are using the best type of sensor in your business.

What is a Pellistor Sensor?

A pellistor gas sensor (also known as a catalytic sensor) is used to find out the vapours and combustible gases in an extremely high range that could lead to explosions. It is made from a platinum wire and a catalyst inside it. Its temperature gets lowered whenever excessive gas is ignited around it. 

When a combustible gas is detected, the temperature and resistance of the pellistor sensor increases and a deficit are created in the resistances of the bead and inert reference bead. Due to the presence of catalysts and beads, it is also known as a catalytic bead sensor. 

In the early 1960s and 1970s, the pellistor sensors were only used as a tool to solve flame safety lamp problems and in canary techniques. Now, however, the usage of these sensors is not limited to just a few industries. In the last few years, the pellistor sensors have become very common and widely used in the industrial sector and for underground construction purposes such as mines, oil rigs, refineries, and tunnels. 

Compared to the other gas sensors, especially IR sensors, pellistor sensors have a lower cost of installation and maintenance. The disadvantage of the pellistor sensors is that they might need to be replaced more frequently than the modern IR sensors. 

Pellistor sensors are a good choice of gas sensors in environments where multiple flammable vapours are found, such as mining areas. Due to their ability to detect numerous gases, pellistor sensors are used by many gas regulators in Malaysia to maintain proper standards.

Drawbacks of Pellistor Sensors

The drawback of the pellistor sensors is that they are not much efficient in areas where the amount of oxygen is low. They require oxygen for the combustion process through which they detect the gases. To avoid this drawback, it is important to install a separate sensor, along with the pellistor gas sensor, to measure the oxygen in narrow areas.

pellistor sensor

Heavy metals like silicon, sulfur, lead, and phosphates can poison the sensors and destroy its sensitivity to detecting gases. The damage to the sensors can be reversible or irreversible, depending on the degree of the poisoning. As a result, safety hazards can be created for the people in areas where sensors are not able to detect an irregular amount of gases. The gas meters can also get damaged.

Exposure to excessive gas concentrations can also damage the gas meters and catalyst sensors. When the sensors get damaged, the gas regulators will not get any notification about the possible damage happening in the environment and the gas equipment.

portable gas detectors

IR Sensors

IR sensor makes use of the infrared light of a specific range of wavelengths that can be absorbed by the targeted gases that you want to detect.
An IR sensor is built from a measurement beam and a reference beam. The role of a measurement beam is to determine the amount of absorbable wavelength by a particular gas. On the other hand, the wavelengths emitted in the form of a reference beam will not be absorbed by the gas.

Both of these beams have similar intensity, and their emissions are deflected with the help of a mirror placed inside the IR sensor. There will be a difference in the intensity of the measurement and reference beam. This difference is essential in calculating the concentration of gas present in the atmosphere where the IR sensor is placed.
sures the efficiency of the gas equipment will not be affected.

IR Sensors versus Pellistor Sensors

In the majority of the cases, the IR sensor is much more efficient than a pellistor sensor. IR sensors can work excellently in places where pellistor gas sensors cannot, such as low oxygen and inert environments.

Moreover, there are significantly fewer chances of sensor poisoning in IR sensor because only a beam interacts with the gas molecules. Fail-safe testing is a significant advantage of an IR sensor. It means that the users are immediately notified if the infrared beam starts failing.

However, there are some drawbacks of IR sensors as well. These gas sensors are vulnerable to thermal shock and strong pressure changes because such gas regulators sensors are not used in areas where gas pressure is continuously fluctuating.

After considering the features and pros and cons of a pellistor gas sensor and IR sensor, you should be able to make a smart decision and install the most suitable sensor your need. Evaluate every aspect of these sensors before making a final decision. Our recommendation is to always choose the most efficient and eco-friendly option available on the market. For more information, feel free to get in touch with us.