How Differential Pressure Transmitters Measure the Liquid Level

In industrial process control and instrumentation, accurate liquid level measurement is critical for many applications such as storage tanks, pipelines, pools, etc. The differential pressure level transmitter is often used to measure differential pressure, but through clever design and principle, it is also capable of liquid-level measurement.

At present, the application of differential pressure transducers in industrial automated production equipment is becoming more and more widespread. However, as a general-purpose measuring instrument, the differential pressure transducer also often causes operational faults. If the problem can not dealt with in time, it will certainly affect the normal operation of production to a certain extent. In this article, we will discuss the working principle of the dp transmitter and explain why it can also measure liquid levels.

The basic principle of the dp transmitter is based on Poisson's law, that is, in a static fluid, the pressure is proportional to the height of the liquid. A dp level transmitter usually consists of two pipes connected to a liquid vessel. One of these two pipes is called the measuring pipe, and the other is called the reference pipe. When the height of the liquid is different, the liquid creates a pressure difference in the measuring pipe and the reference pipe, which can be measured by a differential pressure sensor. Differential pressure sensors usually use a delicate and sensitive diaphragm or pressure-sensitive element.

The level height of the liquid corresponds to the pressure difference between the measuring pipe and the reference pipe of the dp level transmitter. By measuring the pressure difference between the pipe and the reference pipe, the dp transmitter can indirectly measure the liquid level height. When the liquid level rises, the pressure in the measuring pipe increases, while the pressure in the reference pipe remains relatively constant. This results in a change in the electrical signal output from the differential pressure level transmitter, which is proportional to the liquid level height. Therefore, by measuring the output signal of the differential pressure level transmitter, we can accurately determine the liquid level height.

Compared with other liquid-level measurement methods, the differential pressure transducer has some unique advantages. First, it can be applied to a variety of different types of liquids, including corrosive liquids and high-temperature liquids. Second, the differential pressure transducer has a relatively large measuring range, which can meet the needs of different applications. In addition, it has high accuracy and stability, providing reliable level measurement results.

In short, the dp transmitter can not only measure the pressure difference but also indirectly measure the liquid level by measuring the pressure difference of the liquid. Based on the principle of Poisson's law, the dp transmitter utilizes the pressure difference between the measuring pipe and the reference pipe to derive the liquid level height.