Pump Sealing

A question often asked is, which is better for my pump sealing application, compression packing (also known as pump packing) or mechanical seals? This blog highlights the pros and cons of each sealing option and offers guidance for making the right choice for your application.

When compression packing makes sense

For many rotating equipment applications, compression packing is still the preferred sealing choice. Packing comes at a lower acquisition cost than mechanical seals and requires fairly simple maintenance, although maintenance interventions can be more frequent. Some other advantages of compression packing are the following:

  • Ease of installation. Unlike mechanical seals, packing rings can be installed quickly with minimal equipment disassembly. This can allow maintenance personnel to get equipment back up and running quickly, with less downtime.

  • Reduced costs. Compression packing has a lower up-front cost than mechanical seals. The cost differential can be significant as equipment size and complexity increases. In addition, because the same packing can service a wide variety of equipment, inventory and stocking costs can be lower than with mechanical seals.

  • Equipment condition. Compression packing is more forgiving of equipment condition and shaft misalignment than mechanical seals.

  • Severe service applications. Severe service applications are those involving the pumping of heavy slurries and abrasive media. Due to the high-wear nature of these applications, compression packing is the preferred sealing choice due to large equipment size and potential shaft misalignment due to particle impacts.

When mechanical seals make sense

Mechanical seals should always be used on pumping equipment when the media being pumped constitutes a safety, health or environmental hazard. Compared to compression packing, a mechanical seal (or double mechanical seal) can provide a leak- and emission-free seal. Some other advantages of mechanical seals are the following:

  • Improved reliability and equipment uptime. While mechanical seals are more expensive than their packing counterparts, they offer more reliable sealing performance over the long term. This results in lower total lifecycle costs compared to compression packing.

  • Less maintenance interventions. Pumps sealed with compression packing generally require more interventions for adjustment and repacking. These interventions can be avoided with mechanical seals.

  • Less leakage and product loss. Properly installed, compression packing can be relatively leak free. However, in some applications, it is not uncommon to have a little leakage. In addition, the leakage rate can also increase as the packing ages. Leakage can result in safety issues as well as loss of the media being pumped. Mechanical seals, on the other hand, can offer leak-free sealing on pumping equipment.

Choosing compression packing or mechanical seals for a specific pump sealing application will depend upon a careful consideration of the above factors. No matter which sealing option you choose, CRG can help. We can supply CNC-cut mechanical seals that will service most pumping applications, and we maintain a full range of Teadit quality compression packing in stock at all times.

To find out how we can service your needs for compression packing or mechanical seals, please contact our sales team directly at crg@canadarubbergroup.com.