The pressure gauge can indicate and record the pressure value, and can be equipped with an alarm or control device. The pressure measured by the instrument includes absolute pressure, atmospheric pressure, positive pressure (usually called gauge pressure), negative pressure (usually called vacuum) and differential pressure. Most of the measured engineering technology is gauge pressure. The international unit of pressure is Pa, and other units include: engineering atmospheric pressure, bar, millimeter water column, millimeter mercury column, etc.
Pressure is an important parameter in industrial production. For example, when the pressure of a high-pressure vessel exceeds the rated value, it is unsafe and must be measured and controlled. In some industrial production processes, pressure also directly affects product quality and production efficiency. For example, when producing synthetic ammonia, not only must nitrogen and hydrogen be synthesized under a certain pressure, but the pressure directly affects the output. In addition, under certain conditions, measuring pressure can also indirectly get parameters such as temperature, flow, and liquid level.
