What types of sensors are used in controlled environment rooms?

Controlled environment rooms, otherwise called clean rooms or environmental chambers, become essential in pharmaceuticals, biotechnology, the electronic industry, and food processing for tightly controlled environments. Sophisticated sensors drive their effectiveness, and it is in this background that this article will delve into the kinds of sensors used in these rooms and their subtopics.

Thermocouples

Thermocouples are quite versatile temperature sensors fabricated by joining two metals together at one end. They measure temperature by generating voltage proportional to the potential difference across the hot and reference junctions. Their response times are so fast that they find a rather special place in controlled environments and industrial operations; however, they are relatively inexpensive and can easily be optimized for particular applications.

Resistance Temperature Detectors

The RTD device indicates temperature in a very accurate way within a controlled environment. They work on the principle of temperature variation and electrical resistance to a metal like platinum. High accuracy, repeatability, and stability with time are the characteristics of these devices. These features prove very useful for industries related to pharmaceuticals, biotechnology, and semiconductor processing. However, they are costlier and have somewhat slower responses than thermocouples. However, their accuracy is better and more stable; therefore, they are preferred where one requires perfect control over temperature.

Thermistors

Thermistors are temperature-sensitive resistors whose resistance changes with variations in temperature; that is why they are useful for making temperature measurements. There are two types of temperature coefficients: Negative and positive. In the NTC thermistor, its resistance decreases with an increase in temperature, whereas in the PTC type, its resistance increases. Of these, only the NTC thermistors find applications related to temperature sensing and control due to high sensitivity within a limited range of temperatures. They provide quick response times, which makes them especially suitable for applications like medical devices, HVAC systems, and battery management. With a lot less accuracy over a wide temperature range, thermistors are nonetheless price-effective, hugely easy to integrate, and very sensitive at certain limited temperature ranges.

Capacitive Humidity Sensors

Normally, the sensor is manufactured using two conductive plates. This device measures the variations in the polymer film’s dielectric constant and sensor capacitance, which it converts into a corresponding humidity value. Such sensors are used in HVAC systems, industrial process control, meteorology, and consumer electronics. They offer quality readings both in low and high relative humidity, which helps to maintain the conditions in controlled environment rooms at optimum levels.

Thermal Conductivity Humidity Sensors

This device uses two thermistors: one exposed to the environment and the other sealed in dry air. With increasing humidity, there is a rise in heat conductivity through the air; therefore, there will be a temperature difference between the two thermistors. This temperature difference is then converted into a reading of humidity. These include fast response times and durability in high-humidity environments, making them useful for industrial drying processes, meteorology, and HVAC systems. While not in use that much, their accuracy and speed of measurement are still important in maintaining optimal humidity in controlled environments.

Pressure Sensors

Pressure sensors applied in controlled environments ensure an exact amount of pressure impinges on the air, which is essential for operational safety and process integrity. They measure the applied force by coming into contact with a gas or liquid and converting the applied force into an electrical signal for further monitoring and analysis. 

Carbon Dioxide Sensors

CO2 sensors function by infrared absorption, chemical absorption methods, and capacitive techniques. Infrared absorption sensors determine CO2 by the absorbance of IR light. Chemical absorption sensors change colour or electric properties with the presence of a gas. Capacitive sensors sense perturbations along with dielectric properties opposite to CO2 levels. CO2 sensors are devices used to monitor indoor air quality, industrial processes, laboratory and clean room environmental control. This ensures that there is fine ventilation to prevent excessive accumulation of CO2.

In conclusion, controlled environment rooms are equipped with sensors for measuring temperature, humidity, pressure, air quality, and light to maintain the best conditions for industrial and research applications. State-of-the-art sensor technology supports the integrity and quality of processes, products, and precision in industries.