Water activity meterIt is an instrument used to measure the water activity in substances, widely used in industries such as food, pharmaceuticals, cosmetics, etc.

　　Water activity meterBy measuring the ratio of the vapor pressure of water in the sample to the saturated vapor pressure of pure water at the same temperature, the water activity (aw) is calculated within the range of 0 to 1. Common measurement methods include:

1. Dew point method: By using the principle of mirror condensation, measure the dew point temperature of the air above the sample and calculate the water activity. This method has high accuracy and is suitable for laboratory level testing.

2. Capacitive method: using the characteristic of the capacitance value of capacitors changing with humidity to indirectly measure water activity. This method has a fast response speed and is suitable for rapid on-site detection.

3. Resistance method: Calculate the water activity by measuring the change in resistance of the air above the sample. This method has lower cost but relatively lower accuracy.

4. Infrared method: using infrared spectroscopy technology to measure the moisture content in the sample, and then calculate the water activity. This method is suitable for non-contact measurement, but the equipment cost is relatively high.

Application areas of water activity meter:

1. Food industry: Water activity is a key factor in food preservation and shelf life management. Measuring the water activity of food helps determine its shelf life and safety.

2. Pharmaceutical industry: The water activity of drugs has a direct impact on their stability and effectiveness, and monitoring with a water activity meter can ensure the stability of product quality.

3. Agriculture and environmental monitoring: used to measure the storage status of seeds, soil, or feed, help prevent mold or bacterial infections, and can also be used for environmental humidity monitoring.