I have a few questions regarding the control valve assembly; I’d like to ask the experts

First, why can the bypass for control valves smaller than DN25 be placed below the control valve? According to the standards, this is to prevent blockages, but I don’t understand why placing the control valve above can prevent blockages while it can also be placed below; in other words, it could also be placed above the control valve. My understanding is that the drain connections at both ends of the control valve can be placed on the lower bypass, which facilitates liquid drainage. But isn’t it better to place them above? ? ? Secondly, why is it not advantageous for maintenance when control valves and isolation valves are arranged in a straight line? The only time I saw control valves arranged in this manner on-site, I didn’t notice any disadvantages for maintenance; in most cases they are arranged vertically, which saves space. However, there is a problem with vertical arrangement: sufficient installation space must be reserved for the control valves; otherwise, they cannot be installed properly, which is not only inconvenient for maintenance but also for installation. This has nothing to do with ease of maintenance – it’s simply a result of poor design. Therefore, when control valves and isolation valves are arranged in a straight line, insufficient space reservation will hinder maintenance

I didn’t quite understand the reply to the first question. I posted another thread regarding the layout plans for control valve assemblies; one of the proposed schemes involves placing the control valves on the bypass line. The installation method described there is a bit hard to understand. Experts, please take a look at it. The second issue: according to the specifications, there are two reasons. One is that placing them in a straight line requires a large amount of space, and the other is that it makes maintenance difficult