When sealing a centrifugal pump, the challenge is to allow a rotating shaft to enter the ‘wet’ area of the pump, without allowing large volumes of pressurized fluid to escape. When comparing two WARMAN AH Centrifugal Slurry Pumps, side-by-side that has been in operation since 2017 Mechanical Rotating Solutions demonstrated the enormous benefits of choosing the right mechanical seal for the intended pump use.
By replacing the conventional expeller seal on a WARMAN AH Centrifugal Slurry Pump with an AESSEAL® SMSS™ single monolithic stationary seal, Mechanical Rotating Solutions has not only improved the reliability and efficiency of their client’s coal processing plant’s high pressure pump but also eliminated some of the main causes of premature seal failure.
A WARMAN AH Centrifugal Slurry Pump on the left showing excessive leakage compared to a similar pump on the right fitted with an AESSEAL® SMSS™ single monolithic stationary seal. Seal reliability is greatly affected by the seal design and the operating environment.
Whilst many clients still use traditional methods of sealing such as gland packing as a considered cost effective solutions the truth is that this traditional way of sealing a pump will cost more over the long term as a direct result of premature pump failure, increased leakage, higher energy usage and shaft sleeve damage. “Mechanical Seals can count up to 20% of energy savings on kw consumed.” Says Franscois Steenkamp Director of Mechanical Rotating Solutions.
“ Because gland packing is in constant contact with the pump shaft sleeve it will cause threading and that will require a considerable amount of money to repair or replace. We advise our clients on the pro’s and the cons of mechanical seals over traditional seals and try to help them make the right decision to suit their needs. As with the two WARMAN AH Centrifugal Slurry Pumps, and because of its versatility, the WEIR-AH offers a wide range of seal and liner configurations, which enabled us to tailor a solution to our customer’s specific application. Excessive gland leaking caused by expeller seal failure, coupled with a specific gravity (SG) of between 1.0 – 1.15 determined the choice of the AESSEAL® SMSS™ single monolithic stationary seal. The specific seal provides maximum face stability in high pressure and high temperature applications, improving seal life whilst reducing damage to faces in stop/start applications. The AESSEAL® SMSS™ seal was fitted to only one of the two pumps and over the last two years we were able to compare the two pumps side by side and the improvement in performance is absolutely clear for all to see.”
The SMSS™ is part of the AESSEAL® modular sealing system range distributed by Mechanical Rotating Solutions. This, combined with extensive inventory levels, ensures that any standard seal in any size or material combination is available for immediate dispatch.
The AESSEAL® range of single cartridge mechanical seals has been specifically designed to eliminate some of the main causes of premature mechanical seal failure. All seal faces are of monolithic, one piece, construction and therefore are less likely to distort in high and low temperature applications.
Achieving technical performance whilst maximizing modularity is a prime objective in the design of all AESSEAL® products. In addressing the client’s needs The stationary seal face is spring loaded which compensates for angular misalignment between the shaft and the housing.