Real-time monitoring and recording of oil quantity is a regular work in the oil depot system. For safety reasons, the use of electrical equipment is not allowed in the oil depot, and smoke and fire are also strictly prohibited. The traditional fluid level measurement of the oil depot is manually operated. There are size marks inside and outside each oil tank. When it is necessary to measure the oil level, people will be sent to climb to the top of the oil tank, open the top cover, determine the position of the oil surface by visual method, and record the change of the oil amount. The method is troublesome, the measurement error is large, and the oil tank is not allowed to use electricity, all of which bring great difficulty to the automatic measurement. At present, with the rapid development of petroleum industry, the automatic fluid level measurement technology of crude oil storage tank has been paid more and more attention by people. The fluid level measurement is widely used in the industrial measurement. Accurate fluid level measurement is an important means of production process control, especially in the tank detection of petroleum industry. At present, the commonly used tank level measurement is mainly carried out by ultrasonic wave, radar, sensor and other high-tech technologies. The automatic tank level measurement has entered a new stage of multi-function and high precision.
The principle of ultrasonic fluid level sensor is that by monitoring the time difference between ultrasonic transmission and reflection, the fluid level height can be calculated, which boasts a simple installation and high flexibility. But it is easy to be affected by ultrasonic transmission energy loss and is not suitable for microwave absorbing environment, such as foam, dust, steam and other monitoring fields.
Ultrasonic detection technology is used to detect whether the fluid level in the tank reaches the set alarm position. Its principle is by activating ultrasonic sensor to transmit ultrasonic waves and then ultrasonic signal is transmitted into the tank through the tank wall. Because there is a huge difference in the acoustic impedance between the fluid in the tank and air, there is also a huge difference in the ultrasonic energy absorption for these two kinds of media. Therefore, there will be a significant difference in the the strength of energy which is reflected by the tank wall and received by the sensor. Thanks to the above principle, by testing the differences in the received ultrasonic signal energy or amplitude, we can accurately judge whether the fluid level in the tank reaches the set alarm position and control the fluid level by relay.
In addition, the ultrasonic fluid level sensor uses the principle of measuring time difference to measure the height of material. It has strong anti-interference ability, and is easy to install, maintain and use. Besides, it is more suitable for industrial sites with complex environments. It adopts the transmit-receive ultrasonic sensors with a small power, small blind area, high measurement accuracy, stable operation and the function of temperature compensation.
In fact, the precise fluid level of the oil tank in the oil depot is not very important. What the user actually needs to understand is not the fluid level, but the actual amount of oil in the oil tank (that is, the tonnage) through measuring the fluid level, so as to prevent overflowing.