What Is a Level Sensor?

The liquid level sensor (static pressure level gauge / level transmitter / level sensor / water level sensor) is a pressure sensor that measures the liquid level. The static pressure input type liquid level transmitter (level gauge) is based on the principle that the measured static pressure of the liquid is proportional to the height of the liquid, using foreign advanced isolated diffusion silicon sensitive elements or ceramic capacitor pressure sensitive sensors The voltage is converted into an electrical signal, which is then converted into a standard electrical signal (typically 4-20mA / 1 5VDC) after temperature compensation and linear correction.

liquid level sensor

Liquid level sensor (static pressure level gauge /

Divided into two categories: one is contact, including single

1.Float type

Using the principle of static pressure measurement: when the liquid level

Tested medium: liquid (weakly corrosive)

Pressure type:

The liquid level switch is a controller that keeps the water level constant according to the signal output of the liquid level sensor to open the valve for discharging or entering water. It can also be said that the liquid level switch outputs a switching signal. The liquid level switch must first determine the height of the liquid level, and output the switching signal according to this height. The liquid level sensor converts the height of the liquid level into an electrical signal and outputs it. We can process electrical signals such as connecting to a PLC, data collector or professional display to output the level of the liquid level. There is also the principle that the liquid level switch and the liquid level sensor are the same. However, the liquid level switch is a switch control circuit, and the liquid level sensor is a circuit element equivalent to a voltage change and a current change.

The photoelectric liquid level sensor is a new type of contact point liquid level measurement and control device developed using the principle of reflection and refraction at the interface between two different media. It has simple structure, high positioning accuracy, no mechanical parts, no commissioning, high sensitivity and corrosion resistance, low power consumption, small size and many other advantages and has been gradually recognized by the market.

1. Because the output of the liquid level is only related to whether the photoelectric probe is in contact with the liquid surface and has nothing to do with other characteristics of the medium, such as temperature, pressure, density, electricity and other parameters, the photoelectric liquid level sensor detects accurately and has high repeatability; fast response speed The liquid level control is very accurate and can be directly installed and used without adjustment.
2. Due to the relatively small size of the photoelectric liquid level sensor probe, it can be separately installed in a narrow space and suitable for use in a special tank or container. In addition, multiple photoelectric probes can be installed on a measuring body to make a multi-point liquid level sensor and a variable controller.
3. As all the components inside the sensor are resin-sealed, there are no mechanical moving parts inside the sensor, so the photoelectric liquid level sensor has high reliability, long life and maintenance-free.

At the beginning of the 21st century, there are still many challenges in the industrial development of liquid level sensors. It is reported that there are more than 1,700 enterprises engaged in the production and R & D of liquid level sensors in China. The annual output of liquid level sensors has exceeded 2.4 billion, and the liquid level sensor products have reached 10 categories, 42 small categories, and more than 6000 varieties, showing good performance. However, in this enterprise, foreign-funded enterprises have obvious advantages. The proportion of foreign-funded enterprises has reached 67%, especially in Japan, the United States, South Korea, and Germany. The proportion of state-owned enterprises and national enterprises is only 33%. The comprehensive strength of domestic and foreign companies is very small, with a small scale, a shortage of talents, and weak R & D capabilities. It is difficult to compete with foreign companies.

More critically, technically, the domestic level sensor technology is weak, mainly in the following three points:

First, the core technology and basic capabilities are lacking, and core chips rely heavily on foreign imports. Domestic companies have significant gaps with foreign companies in high-precision, high-sensitivity analysis, composition analysis, and high-end aspects of special applications.

The second is the lack of unified standards and independent intellectual property rights in terms of design, reliability, packaging, etc. No breakthrough progress has been made in terms of interfaces, deep etching, high temperature ohmic contact, high reliability MEMS packaging, rapid testing, high simulation and other technologies. Industrialization verification

Third, the products are not comprehensive enough in terms of variety, specifications, series, etc. There are still many differences in technical indicators such as measurement accuracy, temperature characteristics, response time, stability, and reliability. Therefore, the Chinese float level sensor industry has a long way to go.

In recent years, the domestic magnetic flap liquid level sensor market has continued to grow at a rate of more than 10%. In 2010, China s liquid level sensor sales reached 90.5 billion yuan. It is predicted that China's liquid level sensor market will develop steadily and rapidly in the next 5 years. Under the driving force of the large-scale growth of the Internet of Things market, China's liquid level sensor market is expected to reach more than 1.2 billion yuan in 2015.

According to statistics, by 2013, the overall market size of China's Internet of Things will reach or reach 750 billion yuan. As the lowest and most basic link of the Internet of Things "pyramid", the liquid level sensor industry will directly benefit from it.