Concentration Sensor

The Concentration Sensor is a component used in decontamination systems for isolators. It continuously monitors and quantifies the concentration level of sterilizing or decontaminating agents, such as hydrogen peroxide vapor, chlorine dioxide, or peracetic acid, present in the isolator's internal atmosphere during a decontamination cycle. This ensures that the process achieves and maintains the required concentration for the specified duration to guarantee effective microbial kill. The sensor is designed for integration into industrial machinery and equipment, specifically within isolator systems used in pharmaceutical, healthcare, and laboratory settings. It operates on principles such as infrared (IR) absorption, electrochemical sensing, or photoionization detection (PID). For common agents like hydrogen peroxide vapor, an IR sensor measures the absorption of specific infrared wavelengths by the gas molecules, converting this optical measurement into an electrical signal proportional to the gas concentration. The sensor is typically housed in stainless steel, with optical windows made of quartz or sapphire, and a silicon photodetector. Key parameters include a measurement range of 0–2000 ppm for hydrogen peroxide vapor, accuracy of ±2% full scale, response time of less than 10 seconds, operating temperature of 0–50 °C, operating pressure of 80–120 kPa, operating humidity of 0–95% RH (non-condensing), supply voltage of 24 ±10% V DC, output signal of 4–20 mA, ingress protection rating of IP65 per IEC 60529, sensor material of 316L stainless steel per ASTM A240, and weight of 0.5–1.0 kg depending on configuration. These values are typical reference ranges and must be verified for the specific model and application. The sensor is a critical component for ensuring the efficacy of decontamination cycles, and its proper selection, installation, and calibration are essential. When selecting a concentration sensor, consider the specific decontaminating agent, the required measurement range, accuracy, response time, and environmental conditions. Verify model-specific values and standards with the legal manufacturer or supplier before procurement.

The sensor typically operates on infrared (IR) absorption, electrochemical sensing, or photoionization detection (PID). For hydrogen peroxide vapor, an IR sensor emits infrared light at specific wavelengths absorbed by the gas molecules. The amount of absorption is proportional to the gas concentration. A photodetector measures the transmitted light, and the sensor electronics convert this optical measurement into an electrical signal, typically a 4–20 mA current loop, proportional to the concentration. The sensor is designed to operate within specified temperature, pressure, and humidity ranges, and its response time is typically less than 10 seconds to reach 90% of the final value.