The monitoring of residual oil in compressed air is crucial for ensuring the quality of air systems and the normal operation of equipment, especially in industries with strict requirements such as food, pharmaceuticals, electronics, etc. Excessive residual oil may lead to equipment damage, decreased product quality, or environmental pollution, therefore effective monitoring is crucial.
The following are common monitoring methods for residual oil in compressed air:
1. Oil mist separator (oil mist sensor) method
Principle: The oil mist separator measures the concentration of oil mist particles in the air through sensors. When compressed air contains oil mist, the sensor can sense the presence of oil mist and provide the corresponding oil mist concentration value.
Application: This method is suitable for monitoring the presence of oil mist in the air and can display the concentration of oil mist in real time.
Advantages: Simple operation and real-time monitoring.
Disadvantage: It cannot accurately measure moisture and solid particles, and is greatly affected by the particle size of oil mist.
2. Infrared absorption method
Principle: Infrared absorption method detects oil and gas concentration by measuring the infrared absorption characteristics of oil mist in the air. Oil molecules absorb light at specific infrared wavelengths, and sensors can detect this absorption change to calculate the concentration of oil.
Application: Suitable for compressed air with low oil concentration.
Advantages: High sensitivity, suitable for detecting low concentration oil and gas.
Disadvantages: The equipment is relatively expensive and is greatly affected by environmental factors such as temperature and humidity.
3. Light scattering method
Principle: Using the scattering principle of light, the light source shines on the oil mist particles in the air, and the oil mist particles scatter light. The sensor detects the intensity of the scattered light to calculate the oil mist concentration.
Application: Commonly used for high-precision oil mist monitoring.
Advantages: High measurement accuracy and fast response speed.
Disadvantages: The maintenance cost of light sources and sensors is relatively high, and they are affected by the shape and size of particles.
4. Gas chromatography (GC)
Principle: Gas chromatography separates different components of oil and gas in the air, and quantitatively detects the concentration of oil through a detector (such as a FID detector). This method has high accuracy and is suitable for low concentration and trace oil and gas monitoring.
Application: Suitable for laboratories or occasions that require precise data.
Advantages: High precision, capable of detecting various types of oil substances.
Disadvantages: Complex equipment, high cost, and cumbersome operation.
5. Chemical analysis method
Principle: By reacting chemical reagents with oil molecules in the air, measurable chemical substances are generated, and the residual amount of oil is calculated by measuring the concentration of the substance.
Application: Used for on-site testing or laboratory analysis.
Advantages: It can accurately measure the content of oil.
Disadvantage: It relies heavily on chemical reagents and requires certain technical operations.
6. Weight method
Principle: Oil molecules in the air are adsorbed by a filter or adsorbent material, and then the filter or adsorbent material is weighed to calculate the weight of the oil, thereby calculating the concentration of the oil mist.
Application: Suitable for measuring the actual weight of residual oil in compressed air systems, usually used in testing experiments.
Advantages: High precision, able to accurately detect residual oil levels.
Disadvantages: cumbersome operation and high equipment requirements.
7. Oil content monitoring instrument (oil and gas analyzer)
Principle: The oil content monitor monitors the concentration of oil mist or oil gas in the air through various technologies such as light scattering, infrared absorption, chemical reactions, etc. These devices generally have automatic calibration function and can display the oil content in compressed air in real time.
Application: Widely used in various industrial equipment and air systems, especially in demanding fields such as food, pharmaceuticals, electronic manufacturing, etc.
Advantages: The equipment has a high degree of automation, can provide real-time alarms, and ensure stable air quality.
Disadvantages: Large initial investment and high maintenance costs.
8. Mass spectrometry method
Principle: Mass spectrometry analyzes the mass of oil molecules in air samples and quantitatively analyzes them using a mass spectrometer to obtain the concentration of oil.
Application: Suitable for situations that require high-precision detection and analysis of multiple components.
Advantages: High precision, capable of detecting complex oil substances.
Disadvantages: Expensive equipment and complex operation.
Summary:
Low oil mist concentration monitoring: typically using oil mist sensors, light scattering methods, or infrared absorption methods.
Accurate detection: If high-precision oil content measurement is required, gas chromatography or mass spectrometry can be chosen.
Real time monitoring and alarm: Oil content monitoring instruments are usually the ideal choice for real-time monitoring and alarm, suitable for use in industrial sites.
Choosing the appropriate detection method requires comprehensive consideration of factors such as actual application requirements, oil mist concentration, equipment budget, etc.