With a mechanical seal, is a shaft sleeve still needed?
Thread Content
The mechanical seal of a centrifugal pump is used to prevent the medium from leaking outside, while the shaft sleeve serves to protect the main shaft. I have a question: since there is a mechanical seal in place, is it unnecessary to use a shaft sleeve, as the medium won’t leak? Is the shaft sleeve a component of the mechanical seal? What is the relationship between them?
Theoretically, a seal can be used in place of a shaft sleeve, but in most centrifugal pumps equipped with mechanical seals, a shaft sleeve is still used. The main function of the shaft sleeve is to protect the shaft from damage; by wearing out the shaft sleeve rather than the shaft itself, it becomes possible to replace only the shaft sleeve while keeping the shaft intact, which results in lower costs. Most seals are installed on shaft sleeves, so ordinary pumps do not come without them.
Generally, fluorine pumps do not have shaft sleeves. Other metal pumps must exist, right? Replacing the shaft is not only uneconomical but also quite troublesome to repair
Some pumps of ITT do not use shaft sleeves, while almost all the others do. Additionally, the function of the shaft sleeve is also to achieve sealing balance.
It’s mainly a cost issue – the equipment gets worn out, and replacing the shaft sleeve is much cheaper than replacing the shaft itself
If we examine the composition of a mechanical seal in detail, its moving ring is mounted on the shaft via a sleeve, and it is then fixed to the shaft using fastening screws. Therefore, a mechanical seal includes such a sleeve; in other words, the sleeve is part of the mechanical seal
I remember our seals all had bushings
The mechanical seal is the mechanical seal itself; it has nothing to do with the shaft sleeve
In my opinion, mechanical seals have no direct relation to shaft sleeves; the main function of shaft sleeves is to protect the shaft (otherwise why would it not be called a mechanical seal sleeve?) There is also an additional static seal point. ) of. Without it, as long as the dimensions are appropriate, a mechanical seal can still provide sealing functionality. There are many pumps designed for media that do not require high pressure or are not highly corrosive——for example, a significant portion of pipeline pumps come without shaft sleeves.
Depending on the circumstances, it is possible to choose to use a shaft sleeve or to omit it. All the mechanical seals in our unit come with shaft sleeves!
What the original poster said makes some sense; from a sealing perspective, if there is no shaft sleeve, the mechanical seal will not leak, and indeed some pumps do not have shaft sleeves. The choice of pump shaft material is based on mechanical properties. Materials with high mechanical properties often have low corrosion resistance. This can be compensated for with a shaft sleeve. Furthermore, the rotating and stationary rings of mechanical seals are made of sintered materials such as ceramic, which are prone to breaking; without shaft sleeves, the pump shaft will suffer premature damage.