Newbie seeking help regarding the steam condensate bypass issue
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As shown in the figures, Figure 1 depicts the steam condensate entering the heat exchanger, while Figure 2 shows the steam leaving the trap. Why is a bypass provided in both of these diagrams? What is its specific function?
Figure 1 shows the bypass for the pneumatic valve; its two functions are: first, it allows maintenance of the pneumatic valve without disrupting production； 2 is used to compensate for insufficient flow in the pneumatic valve. Figure 2 shows that the trap bypass is similar to the pneumatic valve bypass; the difference is that this bypass compensates for the insufficient capacity of the trap during the cold start-up of the unit.
1: If there are problems with the regulation, it can be temporarily resolved manually; or if the flow rate is insufficient, a bypass can be used to increase the flow rate. 2: If a large amount of condensate is generated at the beginning of the heating process, and the steam trap is not able to remove it quickly, a bypass must be used! This way, it’s probably easier to understand
A bypass is provided to ensure that maintenance of control valves and steam traps does not affect production
Based on the diameter of your main pipeline: the main pipeline has a diameter of 350, while the bypass pipe has a diameter of 35. It is possible to use the bypass pipe to heat the pipeline in the initial stage; once the pipeline is properly heated, then the control valve of the main pipeline can be gradually opened. There is no need for any maintenance work, as even with the bypass pipe fully open, it still isn’t sufficient. As for the steam trap: generally, steam transmission systems are equipped with on-site drain pipes; initially, the condensate valve is closed to allow the condensate to be discharged on-site, until the steam meets the required standards. Once normal operation is achieved, the condensate valve is opened to enable the recovery of the condensate. So what the people upstairs said about it being convenient for maintenance and such isn’t quite accurate here. Of course, generally speaking, if the diameter of the bypass pipe differs not much from that of the main pipe and there is sufficient flow, it is feasible to do so. We usually install bypasses around certain control valves precisely to prevent problems with those valves from preventing timely adjustment; their primary function is to enable adjustment, and only then can the control valves be serviced. The specific situation needs to be analyzed in light of the pipeline details; a rigid application is not feasible.
Well, I misstated it. But what I meant is that typical steam pipeline control valves are equipped with small bypasses