The function of the mechanical seal flushing plan62
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After the sealing modification, the flushing scheme has been changed from P11 to P11+P62. The medium transported by the pump is \"heavy fuel oil\"”； Before the renovation, it was a single-seal design, and the mechanical seal leaked frequently, requiring repairs ； Severe end face wear ； Planned to be modified into a single envelope, P11+P62 ； The reason for adding P62 in the modification is to prevent the medium from condensing and coking at the sealing surface, thereby ensuring reliable operation of the seal. The original purpose of P62 is “extremely cold liquid flushing for cooling,” and P62 is used to flush the back side of the seal; therefore, it is necessary to ensure the cleanliness of the end surface effectively. This is my personal understanding; I’m not sure if it’s correct, so I hope those who are more knowledgeable can give me some advice. The description of P62 in the API is as follows: In Plan 62, a quench stream is introduced from an external source to the atmospheric side of the seal faces. This quench stream can be low-pressure steam, nitrogen, or clean water. It is used in certain single-seal applications to eliminate oxygen and thus prevent the formation of coke (for example, in systems handling hot hydrocarbons), as well as to remove any unwanted material that may accumulate around the dynamic seal components (for example, in systems using caustic or saline substances)
p62 indeed involves rinsing the back side, usually with steam or cooling water, to wash away the material that has leaked there; however, the effect is limited, and the fluid used for rinsing tends to leak easily. Is the temperature of this medium too high, or is it dirty? That’s why 11 doesn’t work. It can be changed to 32 or 53 if conditions permit
If it is possible to use external diesel, it is recommended to change 11 to 32; I have seen that most of the mechanical seals designed with scheme 61 are not actually used……