▼Measurement indicators
Moisture content (%)
▼Application areas
Paper
▼Main components
The infrared moisture sensor consists of two parts: the transmitter and the receiver.
The transmitter head mainly includes: transmitter head box, halogen light source, light source adjustment circuit board, light guide tube, convex lens and other components.
The receiving head mainly includes: a receiving head box, a flexible light-guiding optical fiber, a filter, an infrared detector, a signal amplifier circuit board, a communication circuit board, etc.
▼Measurement principle
Material components have a strong absorption capacity for infrared energy at specific wavelengths, but do not absorb infrared energy at other wavelengths. Select a wavelength that is easily absorbed by the material component as the measurement wavelength, and a wavelength that is not easily absorbed by the material as the reference wavelength. The ratio of the measurement wavelength to the reference wavelength after receiving infrared light passing through the object to be measured is used to establish a mathematical model with the actual content of the object to be measured, and the content of the component of the substance to be measured can be characterized. The main components of paper include water and wood fiber. By selecting three characteristic wavelengths: a characteristic wavelength that is easily absorbed by water, a characteristic wavelength that is easily absorbed by fiber, and a wavelength that is not easily absorbed by both as the reference wavelength; the three characteristic wavelengths are converted into electrical signals through photoelectric detectors, and the ratio of the electrical signal of the water measurement wavelength to the electrical signal of the reference wavelength is obtained from samples with different moisture contents, and the ratio difference is calculated. This value is directly proportional to the water content; similarly, the fiber ratio is directly proportional to the fiber content; the paper water ratio ≈.
▼Technical features
◆ The light source current is divided into 4 levels, and the external control switch can adapt to the difference in light transmittance of different paper products;
◆ Soft start of light source, current stabilization and protection circuit of pulse width modulation, stable, energy-saving and durable;
◆ The measurement gap has multiple reflection and transmission structures, which has higher moisture sensitivity and is insensitive to the fluctuation of the paper line;
◆ Dual detectors detect at the same viewpoint at the same time, and the signal ratio has no parallax time difference, which is suitable for fast scanning;
◆ No rotating parts such as chopping discs, more reliable operation, multiple optical paths for continuous measurement instead of alternating measurement;
◆ The infrared detector uses photovoltaic devices, no dark current, better thermal stability and linearity;
◆ Light intensity signal output mode 4~20mA or 0~10V optional, probe temperature signal current output;
◆ Sufficient pre-calibration samples and data, mathematical graphics software fitting, function curve is closer to the true measurement;
◆ Constant temperature heated blowing plate option, controlled air gap temperature to prevent condensation on the window.
▼Performance indicators
