Is it necessary to remove the instrument for calibration?
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1. Is it necessary to remove the pressure gauge for calibration? Is there any explicit regulation? 2. Are there any regulations regarding the placement of the label indicating that the pressure gauge has passed calibration? Is there any explicit regulation? If so, please specify what the regulations are. Thank you everyone
What conditions are required for calibrating pressure gauges? How to apply pressure when staying on the equipment and pipes? Then how can there be any verification?
Calibrating pressure gauges requires using a pressure pump to apply pressure and comparing it with a standard gauge; this cannot be done on pipes or equipment, so they must be disassembled. For specific standards, refer to JJG 49-2013 \"Calibration Regulations for Precision Pressure Gauges and Vacuum Gauges with Elastic Element Sensors\". Where required by the quality management system, a label indicating that the pressure gauge has passed calibration is attached to it, thereby showing the status of the measuring device.
In China, it is common practice to remove the instrument and use standard equipment for comparative calibration, but internationally, there are methods that do not involve removal. This requires a special instrument valve structure that integrates a table valve. This structure is equipped with inspection holes and isolation valves. However, this approach not only increases costs, but the on-site environment is often unsuitable for carrying out verification work, which in turn increases the fatigue level of the inspectors. So it’s not very practical.
Unit verification should be carried out before installation
There is a testing port near the pressure gauge; can I use a gauge with higher precision for testing? Is this in compliance with laws and regulations? I’ve looked up various sources, but I haven’t found any indication that it’s necessary to remove the gauge in order to calibrate it.
Are the labels stuck on the front side of the pressure gauge glass or inside it? Is there any explicit regulation? Thank you
It should be attached in a location where it is easy to see without affecting the readings; it doesn’t matter whether it’s on the front side of the glass or inside it. If you’re not bothered, you can attach it inside the glass, but this must be done during calibration, as the pressure gauge cannot be removed after calibration.
Gauge calibration should be carried out in a laboratory, but in practice, a label is often just attached to deceive people.
The specifications do not require disassembly; the JJG (measurement calibration regulations) only provide guidance on the methods and procedures for calibrating standard instruments.