Pipeline issues in the PID drawings of foreign process packages.
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In foreign process packages, the design drawings often specify that the pipes should be \"without pockets\" – I’m not sure what this means, so I’d like to ask everyone for their insights. The English term for this is \"without pockets\", and its main purpose seems to be to prevent the formation of condensation within the pipes. In my opinion, \"without pockets\" means that there is no vertical variation in the pipes’ shape. Everyone, share your opinions.
Bag types are divided into upper bags and lower bags, depending on the medium being handled; some are designed to prevent the formation of upper bags, while others are intended to prevent the formation of lower bags
What was said on the 2nd floor is correct: the one facing upward is the air bag, and the one facing downward is the liquid bag. It is generally determined based on the specific requirements of the process medium. The absence of a bag shape does not mean that the pipe does not have vertical movement; rather, it means that the pipe is arranged in a manner that goes lower or higher step by step. Based on personal experience, process flow diagrams usually require the absence of liquid pockets in cases such as two-phase gas-liquid flow or when the medium contains solid particles.
Simply put, it is upper eccentricity and lower eccentricity
Personal opinion: I think the requirements for media without bags are generally quite strict. Liquids are generally required to have no pockets, while gases are generally required to have no gas pockets.
In our facility, the bagless types are usually either BBK or BBL; the specific medium to be used should be determined during the equipment setup
The title is rather mysterious. It’s common to have no pockets; the general requirement for piping is to keep the levels as high as possible or to make adjustments where necessary to lower them. If bag formation does occur, consider venting at higher points and draining at lower points ； For special media, such as flare pipelines, bag shapes must be avoided.
The bag shape is like that of a small GG bag; it’s generally not allowed
The purpose of having no pouch shape is to prevent the accumulation of liquid or gas in the pipes when production stops; it is generally required that the level either rises or falls steadily, so as to completely remove the medium from within the pipes
This is about whether the pipeline pressure should increase or decrease step by step. For liquid media, a decrease in pressure can lead to hydraulic issues that are detrimental to certain discharge pipelines; therefore, drain valves should be installed. For gas media, an increase in pressure can result in air blocks
Generally, what is said more often is \"NO POCKET\", which means that there should be no vertical movement. In other words, the pipeline should run horizontally in one direction or at a certain slope, without any air pockets or liquid pockets (both air pockets and liquid pockets are referred to as POCKETS).
From the perspective of design and operational experience, the absence of a bag is highly important, especially for self-flowing liquids, as the presence of a bag often leads to difficulties in discharging them.
\"Without pockets\" means having no pockets; in the case of gases, it means no gas pockets, and in the case of liquids, it means no liquid pockets. When transporting gas, avoid U-shaped bends at the upper part of the pipeline to prevent gas from accumulating there ； Liquid transfer avoids the U-shaped bend at the lower part of the pipeline to prevent liquid accumulation.
I agree with this, which is why we often translate it colloquially as “no hollows”. For reference only.
Liquids are generally required to have no pockets, while gases are generally required to have no gas pockets.
POCKET also has a container meaning, an indentation! So, no POCKET can be translated as no bends. Usually found on vent and drain lines, with no liquid or gas accumulation.
I get it now too, hehe. Thank you all for your answers.
I roughly understand it; thank you all for the explanations!