Installation of valves upstream and downstream of the safety valve, as well as bypass valves?

It’s so strange; I’ve never seen this before – two safety valves connected in parallel? No way

Two stop valves should be installed on the bypass; this bypass also serves as a vent line, and it is used frequently, so two stop valves are added. In addition, it is advisable to install a shut-off valve in front of the safety valves. The quality of safety valves these days is not reliable, and if there is a leak after the system starts operating, it becomes very difficult to deal with the issue. Moreover, the number of safety valves available is not large.

The design institute does not agree to installing a stop valve below the safety valve; furthermore, it also does not permit the design of an exhaust branch pipe on the safety valve connection

I feel like what you said contains a question. Installing gate valves before and after the safety valve will do. The bypass is a stop valve. As for the bypass you mentioned having safety valves, it’s quite easy to understand – it’s basically like having two safety valves connected to one pipeline. This kind of situation does exist. In process equipment, when high safety requirements apply, two safety valves are installed.

But according to the standards, a stop valve should not be installed in front of the safety valve

Strictly speaking, it is reasonable to install a gate valve upstream of the safety valve, as the quality of current safety valves is indeed poor, especially those of domestic manufacture; they may stop working after some time. Therefore, for safe operation, it is necessary to consider the possibility of replacing them, and it would be best to install one upstream. As for installing two safety valves in parallel, it merely increases the safety factor

1. Within Sinopec’s system, it is stipulated that a shut-off valve must be installed in front of the safety valve; a gate valve can generally be used, and it must be installed on the vertical pipe, with a lead seal in place to ensure its closure. Because safety valves need to be calibrated annually, this ensures that production is not affected. 2. As mentioned on the first floor, if the bypass is a \"safety valve\", then it should be considered as a parallel connection of safety valves. However, if more than two safety valves need to be installed, it is generally not possible to share the same inlet pipe; each safety valve requires its own inlet pipe. 3. If the bypass is a “stop valve (typo),” then it should also serve as a vent line; however, since it is not used frequently, two stop valves should be installed, and they should be set to be sealed with lead seals. Such a practice should also not be encouraged; unless the pipe outlet is truly insufficient, a vent pipe should be installed separately.

Thank you, Floor 8; it was indeed a typo – it should be a stop valve.

1. Within Sinopec’s system, it is stipulated that a shut-off valve must be installed in front of the safety valve; a gate valve can generally be used, and it must be installed on the vertical pipe, with a lead seal in place to ensure its closure. Because safety valves need to be calibrated annually, this ensures that production is not affected. Are there any updates within Sinopec regarding the matter of extending the inspection intervals for some safety valves, as discussed with the relevant departments? 2. As mentioned on the first floor, if the bypass is a \"safety valve\", then it should be considered as a parallel connection of safety valves. However, if more than two safety valves need to be installed, it is generally not possible to share the same inlet pipe; each safety valve requires its own inlet pipe. Why, I think unless the cross-sectional area of the inlet pipe is not sufficient to meet the discharge requirements, a separate inlet pipe would be needed; otherwise, it should be possible to use one common inlet pipe