Precautions for selecting and using pressure gauges

The selection of pressure gauges should be based on specific conditions and the technical requirements of the technical process. At the same time, cost issues should also be considered. We suggest that when selecting a gauge, the following aspects should be considered:
(1) The physical and chemical properties of the measured medium, such as temperature fluctuations, viscosity, dirtiness, corrosiveness, whether it is flammable, explosive, easy to crystallize, etc.
(2) The requirements of the production process for pressure measurement, such as the measured pressure range, accuracy, and whether remote transmission, recording, or upper and lower limit alarms are required.
(3) On-site environmental conditions, such as high temperature, corrosion, humidity, vibration, electromagnetic field, etc.
In addition, for elastic pressure gauges, in order to ensure that the elastic element works reliably within the safe range of elastic deformation, to prevent pressure damage to the elastic element, and to affect the service life of the gauge, the range selection of the pressure gauge must leave a sufficient space. Generally, when the measured pressure is relatively stable, the maximum operating pressure should not exceed 3/4 of the full scale of the gauge. When the measured pressure is relatively unstable, the maximum operating pressure should not exceed 2/3 of the full scale of the gauge. In order to ensure the measurement accuracy, the minimum measured pressure should not be less than 1/3 of the full scale.

2. Use of pressure gauge
In order to ensure the accuracy of pressure measurement, it is necessary to pay attention to the following points when using the pressure gauge:
(1) Selection of measurement point The selected measurement point should represent the actual condition of the measured pressure. The measurement point should be selected in the straight pipe section, far away from some resistance. It is best not to extend the pressure pipe into the measured object but should be flush with the technical pipeline. The inner diameter of the pressure pipe is usually 6~10mm, and the length should not be greater than 50mm, otherwise it will cause transmission lag. In order to prevent the pressure pipe from being blocked, the pressure point is usually selected on the horizontal pipeline. When measuring liquid pressure, the pressure point should be at the bottom of the pipeline so that no liquid accumulates in the pressure pipe; if the liquid on the north side is easy to condense or freeze, it is necessary to install pipeline insulation equipment.
(2) When the equipment measures steam pressure, a condenser or condenser should be installed to condense the steam measured in the pressure pipe. When the measured fluid is corrosive or easy to crystallize, an isolation liquid and an isolation device should be used to prevent damage to the measuring element of the pressure measuring surface. The isolation liquid should be selected from liquids with high boiling point, low freezing point and stable physical and chemical properties. The pressure gauge should be installed as far away from heat transfer and vibration as possible to avoid its influence. A shut-off valve should be installed near the pressure tapping port to be used when repairing the pressure gauge.
(3) During the maintenance and use process, cleaning should be carried out regularly to keep the pressure pipe and pressure gauge clean.