Check valve issue
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A check valve is a device that allows fluid to flow only in the direction of the inlet, preventing the medium at the outlet from flowing back; it is commonly known as a check valve. Current issues with the installation of check valves in newly launched projects: 1. Is it necessary to add a secondary line? 2. In particular, one is available at the outlet of each pump; originally, the two pumps shared one, and it is uncertain whether sharing one is reasonable.
Reply to 1# jbcyf Answer 1: Of course, it’s better to add scaling lines if conditions permit. It is unreasonable for two units to share one check valve; each unit should have its own at the pump outlet. (To prevent failure to carry out timely repairs due to a malfunction in the check valve).
Check valves do not require an auxiliary line, regardless of whether the conditions permit it or not； Each pump must be equipped with a check valve separately; this is a design requirement
Personally, I think there’s no need to add a secondary line! Sharing one seems to work!
In practical operation, if the check valve is located before the outlet valve and the equipment in question operates in a vacuum system, then it is useful to design a bypass line for future use; this is because if the pump cannot be activated due to vacuum conditions or other reasons, the pump can still be operated by pumping fluid through this bypass line. If it is not a vacuum system, then there is no need to install such a bypass line. Additionally, it is not advisable for two pumps to share one check valve – if there is a problem, both pumps will stop working. It is better to have one check valve per pump.
There is no need to add auxiliary lines; it is more reasonable to have a check valve at the outlet of each pump.
It is best to install check valves on each pump in a proper manner; without a bypass line, check valves are meaningless if the valve of the bypass line does not close properly. For heavy oil and hot oil pumps, it is advisable to use a single check valve at the outlet of both pumps, so that the standby pump can be easily preheated. If the medium being transported is a reagent, it is also acceptable for the two pumps to share a check valve.
There is no need to add a secondary line for check valves; in our systems, two pumps share one check valve each. Of course, it is also possible to install a check valve on each pump, but that would increase costs. Additionally, consideration must be given to preventing the pumps from freezing in winter, which requires the use of a small bypass line.
If only one is used, what should be done if the check valve fails?
Current designs feature a check valve at the outlet of each pump, while the original designs had one check valve at the outlet of two pumps. Two pumps with one check valve: 1. Sharing one saves costs. 2. Without the auxiliary line and the connection line to the pump, it is easier to preheat the standby pump in winter. Pump with a check valve at the outlet: 1. Increased investment. 2. A bypass line or connection line must be provided. I think the old design is still better!
Current designs feature a check valve at the outlet of each pump, while the original designs had one check valve at the outlet of two pumps. Two pumps with one check valve: 1. Sharing one saves costs. 2. Without the auxiliary line and the connection line to the pump, it is easier to preheat the standby pump in winter. Pump with a check valve at the outlet: 1. Increased investment. 2. A bypass line or connection line must be provided. I think the old design is still better!