【Y2025】Is it a potential hazard that the gauge does not indicate the red line marking the maximum operating pressure?

The following responses do not contain any content from the attached text and are provided for reference only: The accuracy and reliability of pressure measurement are closely related to the choice of pressure gauge and its method of use. If selected improperly, it will not only fail to accurately reflect the level of pressure but may also cause production accidents. The principles for selecting a pressure gauge are: based on the production process, the properties of the medium being measured, the operating environment, and cost-effectiveness, it is necessary to carefully consider the type, range, accuracy class, and indication format of the pressure gauge.

Spring tube general pressure gauges are typically used for long-term measurement of the pressure of process media on-site. Therefore, when selecting a pressure gauge, it is necessary to meet the requirements for measurement accuracy, as well as ensure safety, reliability, and cost-effectiveness. When the pressure being measured approaches the upper limit of the gauge’s measurement range, although the measurement error is small, operating the instrument continuously at this upper limit pressure will shorten its service life.

When the pressure being measured is below 1/3 of the gauge’s maximum measurement value, although the gauge has a long service life, its measurement error is relatively large. To balance the service life of the pressure gauge with sufficient measurement accuracy, when measuring relatively stable pressures, the value of the pressure being measured should be at 2/3 of the gauge’s upper measurement limit. When measuring pulsating pressure, the pressure value under measurement should be at 1/2 of the upper measurement limit of the pressure gauge. Under normal circumstances, the pressure value to be measured should not be less than 1/3 of the upper measurement limit of the pressure gauge.

The accuracy class of a pressure gauge is primarily determined by the maximum error permitted in production. As long as the measurement accuracy meets the requirements of the production process, there is no need to use a pressure gauge with high precision.

·Gauge pressure meter: A device that uses atmospheric pressure as a reference to measure pressures that are either lower or higher than atmospheric pressure. • Pressure: In fact, it refers to the physical concept of stress, that is, the amount of pressure exerted per unit area.   · Absolute pressure: Pressure measured with respect to the absolute pressure zero point, being higher than that zero point.   · Positive pressure: A pressure value that is below atmospheric pressure, with atmospheric pressure serving as the reference.   · Negative pressure (vacuum): A pressure level that is below atmospheric pressure, measured with atmospheric pressure as the reference.   ·Differential pressure: The difference between two pressures. Gauge pressure: Pressure that is greater than or less than atmospheric pressure, measured with respect to atmospheric pressure.  

1. Indication error: Within the measurement range, the indication error shall not exceed the absolute value of the specified allowable error.   2. Return error: Within the measurement range, the return error shall not exceed the absolute value of the specified allowable error.   3. Tap displacement: After tapping the watch case, the change in the pointer’s reading should not exceed 1/2 of the absolute value of the specified allowable error. 4. Stability of pointer deflection: Within the measurement range, the pointer’s deflection should be stable, with no jumping or sticking occurring.

Classified by measurement range: they can be divided into vacuum gauges, pressure-vacuum gauges, micro-pressure gauges, low-pressure gauges, medium-pressure gauges, and high-pressure gauges, etc.     Classified by working principle: there are liquid-column pressure gauges, elastic pressure gauges, piston pressure gauges, electrical pressure gauges, etc.     Classified by operating environment: they can be divided into ordinary pressure gauges, shock-resistant pressure gauges, explosion-proof pressure gauges, etc.

The following points should be noted when installing pressure gauges: 1. The installation location of the pressure sensing element should be in a place where the flow rate is stable.   2. When measuring the pressure of turbid media containing dust, solid particles, or precipitates, the sensor element should be installed vertically upward.   3. When pressure tapping components are installed on horizontal and inclined process pipelines, the orientation of the pressure tapping ports shall comply with the following requirements: ① When measuring gas pressure, it shall be located in the upper half of the process pipeline. ②When measuring liquid pressure, it is within the range of 0 to 45 degrees from the horizontal centerline of the process pipeline, in the lower half of the process pipeline.