Regarding packing seals
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One of our company’s workshops is equipped with water ring vacuum pumps that use packing seals. When the manufacturer installed them and tested the pumps, there was leakage from the packing at that time; the manufacturer’s technical staff said that this is just how packing seals work. But some pumps I encountered before also used packing seals, with the requirement that there be no leakage. I just checked, and there’s a slight issue with this sentence.
When the liquid leaks out in drops, it indicates that the leakage rate and volume are low, with no splashing occurring
Intentionally allowing a small amount of leakage at the filler is to reduce temperature. Packing seals will definitely cause leakage; if no leakage is allowed, then a magnetic pump must be used.
If a packing seal has no leakage at all, there is a risk of the pump shaft or bearing sleeve melting. The presence of droplets helps to cool the area around the packing. When installing a packing seal, it is usually tightened slightly; after the pump starts operating, the gland is tightened gradually until droplets of liquid appear
The filler doesn’t leak; it’s on the valve: lol
To avoid any leaks, a double-end mechanical seal can be used, though it is relatively expensive! ! !
Refineries often require that no pumps leak at all. Our water pumps also had such requirements in the past; therefore, the type of packing used is crucial. If ordinary asbestos-graphite packing is used, there is a higher likelihood of leakage. It is better to use brand-name packing that is softer and has better self-lubricating properties. During installation, it is important to pay close attention to the angle of the cuts, with the cuts on different rings being offset from each other – this usually solves the problem.
Packing seals generally experience some leakage; otherwise, excessive friction between the graphite packing and the shaft could exacerbate shaft wear.