What Makes a Good Gland Packing?
Characteristics of a Reliable Gland Packing
For a gland packing to give its full power in sealing gases and liquids, it has to show certain properties. One does not simply buy and install any gland packing, and expect it to do its job successfully.
Here are the properties that's worth your time and money.
1. Chemical resistance
They are meant to seal off chemicals - chemicals that are potentially toxic and hazardous. If it reacts to the chemicals it's designed to seal off, it won't be long before the sealing component starts to deteriorate. It would later be flushed away, causing nasty fluid leakage.
2. Anti-friction attributes
While gland packings do their thing, they inevitably rub against the shaft as well as the stationary part lining the stuffing box side. Excessive friction leads to overheating and wear. The unit might even burn because of constant overheating.
3. Lubricant retention
This is one anti-friction property you'll appreciate. These packings have to be covered in lubricants, such as grease, graphite, and petroleum products before they're installed. This is to retard wear and tear caused by friction. A good gland packing has to be able to retain lubricant so that it lasts longer.
4. Shouldn't scratch the shaft
For pumps, shaft sleeves are usually installed over the part where the it is installed. To prevent scratching on the shaft sleeve, it must be non-abrasive. Naturally, non-abrasiveness is a property that won't last forever. It's bound to deteriorate some time, but it should at least last until the next overhaul.
5. Temperature resistance
They are exposed to very wide temperature changes. This means they may be used in unimaginably hot environments. You want a packing that can smoothly resist extreme ambient temperatures as well as the temperature of the liquid being sealed.
See more: pharmaceutical packing equipment
6. Prevent fluid contamination
It's possible for the substances being sealed to be contaminated by itself. Although this doesn't matter in some applications, it's a very crucial matter in industries like the pharmaceutical and food markets.
7. Resilience and compressibility
This means that it must have the ability to confirm and compress firmly and adequately under the pressure of the gland flange. When this pressure is released, it must return to its original form.
8. Non-corrosive
Lastly, a non-corrosive packing helps prevent damage to the housing and the shaft.
Gland Packing and Shaft Installation Pre-conditions
Even if you have thoroughly followed every step in the manufacturer's instructions and regardless of how many times the packing has been changed, there are still other factors that determine a packing's efficiency.
1. The shaft's structure. A bent shaft would consume the packing too early, and you have no other choice but to change the shaft. Before the overhaul, use a dial gauge to check the shaft's trueness.
2. The shaft's surface roughness. Shafts or sleeves that are unevenly worn or pitted may damage packings earlier than expected.
Aside from a trustworthy gland packing, a reliable shaft is necessary for ultimate sealing solutions. Keep this guide in mind to take the full advantage of a gland packing.