How to determine if the pressure gauge's range is suitable?

The core principle for determining whether a pressure gauge's range is suitable is that "the actual working pressure falls within the 1/3 to 2/3 range of the scale." This is the optimal choice, balancing measurement accuracy, equipment lifespan, and safety protection. The following steps and points can be used to make this determination:

Safety Protection Redundancy

For high-pressure, flammable, and explosive media (such as oil and gas pipelines, high-pressure boilers), the upper limit of the range can be appropriately increased to 1.5 to 2 times the working pressure to prevent damage to the pressure gauge in case of overpressure. However, it must be ensured that the steady-state pressure remains within the 1/3 to 2/3 range.

Example: For a high-pressure pipeline with a working pressure of 10MPa, a range of 0-16MPa (1.6 times) can be selected. 10MPa is 62.5% of the range, which meets the requirement of being within 2/3.

Viscous/Crystallizing Media

These media are prone to clogging the pressure gauge interface and require the use of a diaphragm device. The range selection still follows the 1/3 to 2/3 principle, but it is recommended to reserve a 10% to 20% range margin to cope with pressure fluctuations caused by media crystallization.

Low-Pressure Measurement Scenarios

When measuring very low pressures (e.g., ≤0.1MPa), if the range is too large, the pointer deflection angle will be small, resulting in large reading errors.  A small-range pressure gauge (e.g., 0-0.1MPa, 0-0.25MPa) should be selected to ensure a noticeable pointer deflection.