Differential pressure transmitter is a transmitter to measure the pressure difference between two ends of the transmitter. It outputs standard signals (such as 4-20mA, 0-5V), which are used to measure the liquid level, density and pressure of liquid, gas and steam.

What problems should users pay attention to when choosing the differential pressure transmitter? The following is a brief introduction to the selection points of the differential pressure transmitter, hoping to help users better apply the product.

Selection key points of differential pressure transmitter:

1. Measurement range, required accuracy and measurement function;

2. The environment faced by the measuring instrument, such as the industrial environment of petrochemical industry, has the presence of combustible (toxic) and explosive dangerous atmosphere, high ambient temperature, etc;

3. Physical and chemical properties and state of the tested medium, such as strong acid, strong alkali, viscous, easy to solidify, crystallize and gasify;

4. Change of operation conditions, such as change of medium temperature, pressure and concentration. Sometimes, the change of concentration and density of gas phase and liquid phase should be considered from start-up to normal production;

5. The structure, shape, size, equipment accessories and all kinds of inlet and outlet pipe orifices of the tested object container shall be considered, such as tower, solution tank, reactor, boiler drum, vertical tank, spherical tank, etc.; 6. Other requirements, such as environmental protection and sanitation requirements;

7. The selection of engineering instrument shall be considered in a unified way, and the variety and specification shall be reduced as much as possible, and the spare parts shall be reduced for the convenience of management;

8. Specific requirements of process patentee.

9. Actual process:

1) consider what kind of equipment the tested object belongs to. For example, tank and tank, the volume of tank is small, the measurement range is not too large, the volume of tank is large, and the measurement range may be large;

2) depending on the physical and chemical properties and cleanliness of the medium, the conventional differential pressure transmitter and float type liquid level transmitter are preferred, and the material of the part contacting the medium is also selected;

3) for some suspended solids, foam and other media, single flange differential pressure transmitter can be used. Some easy to separate out and crystallize use plug-in double flange differential pressure transmitter;

4) for the liquid level of high viscosity medium and high-pressure equipment, because the equipment cannot be opened, the radioactive liquid level meter can be used for measurement;

5) in addition to measurement methods and technical problems, there are also instrument investment problems.

The composition of differential pressure transmitter is very complex, and there are many parts, so there are many problems to be paid attention to in the process of installation and disassembly.

Next, I will introduce some disassembly methods of capacitive differential pressure transmitter, hoping to help you.

Disassembly method of differential pressure transmitter:

1. The signal terminal (power terminal) can be reached by unscrewing the meter cover on the terminal side. They are firmly fixed in the electrical box and should not be disassembled. Otherwise, the seal between the two chambers will be damaged, thus damaging the explosion-proof structure of the chamber and failing to reach the explosion-proof rated value.

2. Screw off the meter cover on both sides of the circuit to reach the intelligent electronic components and the display meter, and form a good habit; disconnect the power supply first, and then remove the meter cover on the circuit side.

3. Screw out the M4 screw fixed on the circuit board and screw it into the M4 screw hole corresponding to the amplifier board, then the amplifier circuit analysis can be pulled out.

4. For the verification circuit board, align the zero position and range adjusting screw first, so that the slot on it is perpendicular to the verification board, so that the verification board can be easily removed.

5. Remove the nameplate and the open retainer ring installed on the screw for zero adjustment and zero adjustment, then the zero position, range and adjustment screw can be removed.

Separation of components of differential pressure transmitter and electrical box:

1. Remove the amplification circuit board and validation board as described above.

2. Loosen the locking screw.

3. Screw off the sensor assembly from the electrical box, be careful! Do not damage the lead on the assembly, and carefully pull out the outlet socket of the sensor assembly from the hole on the electrical box. Please pay special attention to that when screwing off the sensor assembly, do not damage the diaphragm of the assembly.

4. The capacitive transmitter assembly is an integral welding part, which can no longer be disassembled.