How it Works: By detecting the diffusion of a.deniatbo certain amount of gas, oxygen passes through the gas - permeable membrane into the interior of the sensor. It is consumed between the electrode and the electrolyte, generating an electric current between the anode and the cathode. The intensity of this current has a linear relationship with the oxygen concentration, thereby indirectly detecting the formaldehyde concentration. When formaldehyde gas reacts with the electrodes in the sensor, a corresponding electrical signal is generated. Through the measurement and analysis of this electrical signal, the formaldehyde concentration can be obtained.
Real - world Example: Some high - end indoor air quality monitoring sensors, like the Sensirion SFA30, use the electrochemical principle to accurately detect formaldehyde levels in homes and offices.
B. Photoionization Principle
How it Works: It consists of an ultraviolet lamp hidden under a special optical filter. The lamp emits light only at 10.6eV. The target gas diffuses into the interior of the sensor. Gases with an ionization voltage less than 10.6eV are ionized by the radiation emitted by the ultraviolet lamp and release free electrons. These free electrons are captured by high voltage, generating a current signal related to the concentration of the target gas. The concentration of the target gas is detected by comparing the current intensity.
Real - world Example: The Aeroqual Series 500 sensors often utilize the photoionization principle for detecting formaldehyde in industrial settings where quick and accurate detection is crucial.
C. Semiconductor Gas - sensitive Principle
How it Works: It utilizes the adsorption and reaction characteristics of semiconductor materials to formaldehyde gas. When the surface of the semiconductor gas - sensitive material adsorbs formaldehyde gas, its electrical properties change, such as a change in resistance value. The change in these electrical properties is measured to sense the formaldehyde concentration.
Real - world Example: The Figaro TGS2602 is a well - known semiconductor - based formaldehyde sensor commonly used in low - cost air quality monitors.
II. Characteristics
A. High - precision Detection
Precision Level: It can accurately measure the formaldehyde concentration in the air, with precision reaching a low concentration unit, such as the ppb (parts per billion) level. For example, some advanced sensors can detect formaldehyde concentrations as low as 1 ppb, which is extremely precise and can meet the requirements for precise formaldehyde concentration detection in different scenarios.
B. Intelligent Calibration
Calibration Methods: It has an automatic calibration function. Through methods such as online calibration and dynamic calibration, it can eliminate the influence of sensor drift. For instance, some sensors can calibrate themselves every few hours to ensure long - term stable detection accuracy, reducing the cumbersome work and errors of manual calibration.
C. Fast Response
Response Time: It responds rapidly to changes in formaldehyde gas. Some sensors can detect fluctuations in formaldehyde concentration within seconds and promptly output the detection results, enabling users to take corresponding measures in a timely manner.
D. Strong Anti - interference Ability
Interference Suppression: By using advanced materials and algorithms, it can effectively suppress the interference of other gases, such as alcohol, carbon monoxide, etc. For example, in a laboratory environment where multiple gases are present, a high - quality formaldehyde sensor can still accurately detect formaldehyde levels.
E. Data Processing and Analysis
Functions: It can perform real - time processing and analysis on the collected data. It can not only directly display the formaldehyde concentration value but also evaluate the air quality status through built - in algorithms, such as judging whether it exceeds the standard and giving health risk warnings. Some sensors can also establish pollution release and attenuation models to predict the changing trend of formaldehyde concentration.
F. Intelligent Internet of Things
Communication Protocols: It supports multiple communication protocols, such as WiFi, Zigbee, Bluetooth, etc. It can be connected to smart devices such as mobile phones and tablets, and can also be integrated into the smart home system to achieve remote monitoring and control. For example, a user can check the formaldehyde concentration in their home through a mobile app.
III. Application Fields
A. Home Environment Monitoring
Well - known Project: Many smart home projects, like those in high - end residential communities, use intelligent formaldehyde sensors to ensure the health of residents, especially for sensitive groups such as pregnant women, infants, and the elderly.
B. Commercial and Office Places
Company Example: Large office buildings of companies like Google and Microsoft use intelligent formaldehyde sensors to monitor indoor air quality and provide a healthy and comfortable environment for employees.
C. Industrial Production
Industry Application: In the chemical industry, companies like BASF use these sensors to monitor the formaldehyde concentration in their production workshops and exhaust gases to ensure worker safety and environmental protection.
D. Medical and Scientific Research
Research Use: In medical research institutions such as the Mayo Clinic, intelligent formaldehyde sensors are used to precisely control and measure the formaldehyde concentration in specific experimental environments.
E. Cultural Relic Protection
Museum Example: Museums like the Louvre use intelligent formaldehyde sensors to protect their precious cultural relics from formaldehyde pollution.
IV. FAQ
Q: How often should I calibrate my intelligent formaldehyde sensor?
A: It depends on the sensor model and the environment. Some sensors with intelligent calibration can self - calibrate regularly, while others may require manual calibration every few months or years. Check the product manual for specific instructions.
Q: Can the sensor be affected by temperature and humidity?
A: Yes, extreme temperature and humidity can affect the sensor's performance. However, many high - quality sensors are designed to compensate for these factors to ensure accurate detection.
Q: How long does an intelligent formaldehyde sensor last?
A: The lifespan of a sensor varies. Generally, it can last from 2 to 5 years, but this can be affected by usage conditions and maintenance.
