Valve issues on the pipeline
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Dear experts: Why are double valves sometimes installed on pipelines? And why is a blind flange added to one of the valves? How is the position of the blind flange determined?
For some pipelines carrying toxic, corrosive, or high-pressure materials, a handshake connection is generally used in dual configurations; blind plates serve as boundaries between different sections. They are also used to purge the equipment connected to the main material pipelines, and at the same time to isolate those connections from the utility lines that are connected to the material pipelines
It’s likely due to frequent opening and closing of the valve; the use of two valves is intended to facilitate its replacement.
To ensure coverage during the insurance period, dual valves should be used – if one fails, the other will still function
Dual valves are installed as a safety measure; they are generally used in situations where the medium is hazardous or at high pressure. Blind flanges are used for purging purposes, with 8-shaped blind flanges being the most common type, and they are installed on either flange face between two valves
Two valves should be installed on the pipes of the equipment in each branch system, to prevent problems that may arise if the flow of fluid in a particular branch line is interrupted; these two valves serve that purpose； Blind plates are installed to prevent accidental operations, or in pipelines that remain closed for long periods with valves that do not seal properly ； At the valves of the connecting pipes for equipment that is toxic, hazardous, or under load, blind plates should be installed for safety reasons prior to maintenance; the location where these blind plates are placed is determined based on safety and operational requirements. (For reference)
The first valve should be called a maintenance valve; it remains open at all times and is used as a safety measure only in case of abnormalities. Some also have three main valves. If you need to add blind plates, it depends on what you are doing. A blind flange is primarily used for effective isolation.
Where the pressure of the medium in the pipes of system equipment is greater than 4 MPa, two valves should be installed to prevent problems that may arise if fluid flow in a certain branch line is interrupted; in other words, this is done to ensure safe operation.