With the development of science and technology, the introduction of energy conservation and emission reduction policies, the measurement of DC power has been widely used in industrial production and scientific research experiments, and the measurement of DC power is of great significance. The flow and application are extensive.

[9 precautions for instrument technology selection]

1. Measurement range, necessary accuracy and measurement function: the minimum pressure measurement value is greater than 1 / 3 of the pressure gauge measurement value, requiring telemetry and measurement accuracy.

If the requirements are high, the pressure sensor or pressure differential pressure sensor shall be selected; if the measurement accuracy is not required, the resistance type or electromechanical, Hall effect centrifugal pressure gauge can be selected; the movement of air is a pressure gauge.

The basic pressure indicating regulator is suitable for local pressure indicating regulation.

2. The structure, shape, size, accessories in the vessel and nozzles of various input / output materials must be considered: for example, tower, solution tank, reactor, boiler drum, tank, spherical tank, etc.

3. There must be a unified idea for process selection: try to reduce the variety standard, the number of tooling and fixture, and carry out profit management.

4. Environment faced by pressure gauge: for example, in the industrial environment of petrochemical industry, there is a flammable (toxic) explosion dangerous atmosphere, and the ambient temperature is relatively high, so the work of pressure sensor and pressure switch should be done well.

5. Reasonable selection according to the detonation requirements of the installation site.

6. Actual process: which equipment should be considered. For storage tank and storage tank, the volume of storage tank is small, the measurement range is small, and the volume of storage tank is large, so the measurement range is possible to be large.

7. According to the nature and cleanliness of the medium, the positive pressure difference sensor and float type liquid sensor are selected to select the material contacting the medium. The single flange differential pressure sensor can be used as the medium of float and bubble. There are some plug-in double flange differential pressure sensors which are easy to precipitate and crystallize.

8. The liquid level of high viscosity medium and high pressure device shall not be perforated.

9. Other requirements, such as environmental protection and hygiene requirements and specific requirements of process patents. Of course, in addition to measurement methods and technical problems, there are also problems in instrument investment. Physical and chemical properties and state of the tested medium: strong acid, strong base, high viscosity, easy to solidify. Change of operating conditions: change of medium temperature, pressure and concentration. From operation to normal production, concentration and density of gas phase and liquid phase can be considered.