Definition, classification, function, principle, and characteristics of pressure transmitters

Generally speaking, pressure transmitters are mainly composed of three parts: load cell sensors (also known as pressure sensors), measurement circuits, and process connectors.

It can convert the physical pressure parameters such as gas and liquid sensed by the load cell sensor into standard electrical signals (such as 4-20mADC) for supply to secondary instruments such as indicator alarms, recorders, regulators, etc. for measurement, indication, and process adjustment.

Classification of pressure transmitters

Pressure transmitters can be divided into three types based on the measurement range: general pressure transmitters (0.001MPa~35MPa), micro differential pressure transmitters (0-1.5kPa), and negative pressure transmitters; From the perspective of accuracy, since our national standard has an accuracy of 0.5%, it can be further divided into high-precision pressure transmitters (0.1% or 0.2% or 0.075%) and general pressure transmitters (0.5%) in recent years.

The function of pressure transmitter

The pressure transmitter transmits the pressure signal to the electronic device, which then displays the pressure on the computer.

The principle of pressure transmitter:

Transforming the mechanical signal of water pressure into an electronic signal of current (4-20mA) is a linear relationship between pressure and voltage or current, usually in direct proportion. Therefore, the voltage or current output by the transmitter increases with the increase of pressure, resulting in a relationship between pressure and voltage or current.

The two pressures of the tested medium of the pressure transmitter are introduced into the high and low pressure chambers, and the low pressure chamber presure is either atmospheric pressure or vacuum, acting on the δ On both sides of the isolation diaphragm of the element (i.e. sensitive element), the filling liquid inside the element is transmitted to both sides of the measurement diaphragm through the isolation diaphragm. A pressure transmitter is a capacitor composed of a measuring diaphragm and electrodes on both sides of the insulation sheet. When the pressure on both sides is inconsistent, it causes displacement of the measuring diaphragm. The displacement is proportional to the pressure difference, so the capacitance on both sides is unequal. Through oscillation and demodulation, it is converted into a signal proportional to the pressure.

Characteristics of pressure transmitters

1) The tested medium is widely used and can measure oil, water, and paste compatible with 316 stainless steel and 304 stainless steel, with a certain degree of anti-corrosion ability.

2) High accuracy, high stability, selection of imported original sensors, good linearity, and high temperature stability.

3) Small size, light weight, convenient installation, debugging, and use.

4) Stainless steel fully enclosed shell, waterproof.

5) The pressure sensor directly senses the measured liquid level pressure and is not affected by medium foaming or deposition.