Root valve of pressure gauge on pressure pipeline

A root valve is generally required at the base of the pressure gauge on pressure pipelines; for specific requirements, refer to \"GB/T1226 General Technical Conditions for Pressure Gauges\" and relevant industry standards. This is mainly done to allow the medium to be cut off during installation and maintenance, ensuring safety. .

It must be installed; generally, pressure gauges need to be calibrated every six months, and it is definitely necessary to remove them after cutting them out； Pressure gauges are also considered wear-prone components, and they are easy to replace

If your equipment can be shut down at any time and the load in the pipeline can be adjusted arbitrarily, it may not be necessary to install it. However, overall, it’s better to install it. This is because the costs associated with starting and stopping equipment and handling the resulting load are far higher than those of a small valve, not to mention the other uncertainties arising from frequent operations; for reference only.

It’s not mandatory, but when making the selection, it is possible to agree with the manufacturer on using a pressure gauge that comes equipped with a root valve

Take the selection of a one-time sourcing check valve as an example. The source primary root valve is located at the root of the instrument measurement pipeline‚ Its main function is to establish and disconnect the connection between the instrument measurement pipeline and the process pipeline. Since the primary valve is in direct contact with the process medium, it faces the most severe operating conditions throughout the entire measurement pipeline; it is also the most critical component. Once a failure occurs in this valve, it is difficult to carry out repairs or replacements online. In most process fluids in refinery units, a small amount of solid particles are inevitably present‚ Over time, these solid particles gradually accumulate within the measurement pipelines. Since the process medium in the instrument measurement pipeline is at rest, unless flushing or backwashing methods are used, it is difficult to remove solid particles from the sample takeoff nozzles and primary control valves. To avoid blockages at the valve inlet as well as internal leakage of the valve caused by solid particles getting trapped in the sealing surfaces, parallel double-disc valves are generally used as the primary valve for taking samples in low-pressure applications. T-shaped globe valves are not recommended in such cases, while Y-shaped globe valves are more suitable for high-pressure applications.

I want to know which standard specifies whether a root valve is required.

Doesn’t any teacher know? Everyone knows what needs to be added, but which standard specifies it.

This is indeed unclear; you can go to the “Pipes and Valves” section to ask