Common classification of liquid level switches

　　Liquid level measurement is a key link in realizing automated production of industrial processes. It can be divided into switch measurement and continuous measurement according to its output. Due to the wide variety of liquid level switches on the market, most users do not understand the functions of liquid level switches, and middlemen such as dealers and distributors rarely understand the on-site working conditions. These various types of liquid level switches have caused many obstacles for users to make correct choices. Users urgently need to understand the common classification of liquid level switches in order to purchase liquid level switches that match the actual working conditions. To this end, this article introduces the common classification of liquid level switches as follows, hoping to be helpful to instrument users.

1. Capacitive liquid level switch

　　After the capacitive level switch probe contacts the liquid, it detects the change in capacitance and outputs a contact signal. Generally speaking, capacitive level switches have certain advantages in measuring slightly viscous media.

2. Electrode type liquid level switch

　　Electrode type liquid level switch mainly uses the conductivity of liquid to detect the height of liquid level. Once the measured medium touches the electrode, it will conduct electricity and thus detect the signal. After the signal is amplified by the controller, a contact signal is output to realize the control of liquid level.

3. Float level switch

　　The magnetic float of the float level switch rises or falls with the liquid level, causing the reed switch chip at the set position in the sensor detection tube to operate and send out a contact open/close conversion signal. Due to its simple structure, economical and practical, the float level switch is widely used in the civilian market, but its stability is relatively poor compared with industrial-grade products.

4. Photoelectric Liquid Level Switch

　　Photoelectric level switches mainly use the principle of light refraction and reflection to detect through infrared rays. Since light will be reflected or refracted at the interface between two different media, when the measured liquid is at a high level, the measured liquid and the photoelectric switch form one interface, and when the measured liquid is at a low level, the air and the photoelectric switch form another interface. These two interfaces make the reflected light intensity received by the light receiving crystal inside the photoelectric switch different, corresponding to two different switch states. Generally speaking, compared with other measuring instruments, the applicability of photoelectric switches is poor.

5. Ultrasonic external liquid level switch

　　The instrument probe of the ultrasonic external liquid level switch emits ultrasonic waves and detects the residual vibration signal in the container wall. When the liquid overflows the probe, the amplitude of the residual vibration signal will decrease. After the instrument detects this change, it outputs a switch signal. Since the ultrasonic external liquid level switch is a non-contact measuring instrument, it is mostly used in high-risk places where it is difficult to open holes on site, but relatively speaking, its cost is relatively high.

6. Tuning fork level switch

　　The tuning fork liquid level switch mainly outputs a switch signal by detecting the changes in the frequency and amplitude of the fork vibration. It is highly versatile, but for working conditions with high viscosity, it is necessary to consult the manufacturer to confirm. It is not recommended for working conditions that are prone to crystallization.