Pumps solutions provider Mechanical Rotating Solutions (MRS) contributed to a Limpopo-based platinum mine’s water-saving initiative towards the end of 2019 by replacing the existing pump gland packing with AESSEAL single cartridge seals.

Pumps solutions provider Mechanical Rotating Solutions (MRS) contributed to a Limpopo-based platinum mine’s water-saving initiative towards the end of 2019 by replacing the existing pump gland packing with AESSEAL single cartridge seals.

The replacement project resulted from the mine’s conclusion that its 24 service pumps were losing more than 252 000 ℓ/y of water.

By replacing the conventional stuffing box gland packing of the original-equipment manufacturer (OEM) centrifugal slurry pumps with technologically advanced AESSEAL single monolithic stationary seals, MRS also improved the reliability and efficiency of the plant.

“We installed the first eight seals in September last year and, following inspection, these pump areas are completely dry and no further water wastage has been reported. Owing to its versatility, the OEM pump that was initially chosen by the client offers a range of seal and liner configurations, enabling our customers to use tailored solutions for their specific application,” explains MRS MD Franscois Steenkamp.

He highlights that the undue gland leaking, as well as the specific gravity of 1:1 necessitated the use of AESSEAL single monolithic stationary seals. They provide maximum face stability in high-pressure and -temperature applications, which improves seal life while reducing damage to faces in stop/start applications.

He adds that seal faces are monolithic constructions, ensuring that they are less likely to distort in high- and low-temperature applications.

All the seals are also supplied with “thin” inboard seal faces. “This reduces heat generation at the seal face and minimises the heat load on the seal flushing system. The stationary seal face is also spring-loaded, which compensates for angular misalignment between the shaft and the housing,” Steenkamp elaborates.

“During the past decade, this particular single-cartridge seal has evolved in line with the advancement of seal face material technology, which means that it is now capable of handling mild slurry applications.”

He confirms that, as a result of this involvement with the platinum mine, MRS has been awarded a R1-million order for an additional 14 seals, which will be installed and commissioned early this year.

“We have now been granted the opportunity to investigate further water savings on the plant’s thickener underflow pumps and to install mechanical seals.”

Seal Improvements

Steenkamp stresses that, while gland packing seals are a more affordable sealing solution, and provide opportunities for simple and temporary maintenance, mechanical seals offer a “more rewarding return on investment”.

This is because the loss of fluids will progressively increase as the gland packing material begins to wear. This may spoil the seal’s regular lubrication or reduce its ease of replacement that is required for adequate function.

Moreover, “mechanical seals are more versatile and generally preferred over traditional packing seals, as they can be used in a more diverse range of applications. AESSEAL mechanical seals are more durable than gland packing and are designed to handle more abrasive materials.

“In a water-scarce country, water management and conservation is coming to the fore as one of the most important aspects of mining, and is a key consideration for government in terms of the approval of mining licences,” he stresses.

Steenkamp reiterates the importance of having versatile sealing solutions when working with industry-leading pumps manufacturers, and that equipment reliability can be improved by changing the seal environment or upgrading the seal design.

He notes that peripheral speeds and pressure velocities are vital factors when considering appropriate mechanical seals for an application.

MRS can provide affordable seal conversion kits to upgrade seals that are not AESSEAL designs or change the OEM equipment seal environment to significantly improve seal life.

Over the past decade, MRS has worked with various clients to change seal methods, improving pump reliability and reducing the likelihood of breakdowns and downtime. As a result, it has assisted several clients in reducing maintenance costs and improving overall efficiency.