Prerequisites for modifying the mechanical seal of liquid hydrocarbon pumps to a tandem mechanical seal
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Our factory wants to replace the mechanical seals of the liquid hydrocarbon pumps with tandem-type seals. We would like to know how to determine whether our pumps can be fitted with tandem seals, and whether it is necessary to replace the pump shafts Is it necessary to use the PLAN52 flushing procedure after replacing the series seal?
First: It depends on whether there is sufficient installation space; you need to provide the manufacturer of the mechanical seal with detailed dimensional information, and they will help you select the appropriate model； Second: Generally, there is no need to replace the pump shaft; if the shaft of the ring pump does need to be changed, then the positioning holes will also have to be altered. In such cases, it’s better to replace the entire pump. The choice of flushing method depends on the type and properties of the medium, as well as the process conditions and available facilities – it’s not necessarily necessary to use Plan 52
Thank you very much. I also would like to ask about the feasibility of using dry gas seals in mechanical pumps for liquid hydrocarbon media
Check if there is enough space for installation. If you have detailed dimension information [shaft diameter? Cavity? Axial length....】 I can help you determine it
I need to consult the pump manufacturer first; we don’t have the size information
This can only be determined by a professional manufacturer through calculations based on the actual operating conditions. As far as I know, no one chooses this approach; generally, Plan 52 is used for collecting seal leaks, with other methods employed to provide buffering and isolation between the sealed chamber and the atmosphere
Inform the mechanical seal manufacturer of the pump model so that they can determine whether it is possible to make modifications； If the machine seal manufacturer is unable to determine the installation dimensions, on-site measurement can be carried out.
As long as the axial dimension is long enough, that’s sufficient. Note that after changing to a series configuration, there are two mechanical seals and a pumping ring, etc.; as the axial dimension increases, the size of the sealing chamber also increases. The shaft generally remains stationary; placing a shaft sleeve is sufficient. Even if it is changed, it is still very necessary to use API PLAN 52
Changing from a single seal to a dual seal depends mainly on whether the sealing chamber of your equipment meets the dimensions specified in API682. If the dimensions allow, it is generally possible to switch to a dual-seal configuration of 11+52 or 53a
Do not use PLAN52. Use the PLAN53 system; it operates under pressure and is more suitable for your light hydrocarbon pumps. Its price is slightly higher than that of PLAN52, but it provides a one-time solution. Changing to a double-seal mainly depends on the space available in the pump; if it’s not sufficient, the pump cover can be modified, and many people are doing this these days. High-risk pump renovation,
For flammable and explosive media, it would be much better to use a dry gas seal, provided that the dimensions of the chamber in which the seal is installed are sufficient.