Curve® Superior Sealing Capabilities

Pump and Abrasion Technologies^® (PABT) is an Original Equipment Manufacturer and global supplier of heavy-duty slurry pumps and custom pumping solutions. We are committed to ensuring customer satisfaction and pride ourselves on supplying our clients with premium quality, impact-reducing products.

Our flagship Curve^® range of slurry pumps are designed in South Africa and tested in real mining applications to achieve the highest in-class ratings in robust and wear-resistant performance.

One of the biggest challenges in slurry pump design and operation is ensuring the medium (or slurry) being transported by the pump is maintained in the pump itself. To accomplish this, PABT developed three unique sealing configurations for the Curve^® range of slurry pump: 

• Dry Gland Configuration (Expeller Sealed Configuration)
• Wet Gland Configuration (Full gland packed stuffing box with supplied gland service water)
• Mechanical Seal Configuration

‍‍Dry Gland Configuration

The dry gland sealing configuration or more commonly known as the expeller seal configuration, is used primarily in the mining industry. This configuration operates as a dynamic seal in which the expeller (or secondary impeller) acts as an extraction fan and makes use of centrifugal forces to ensure the medium is contained in the volume of the slurry pump and does not emerge from the sealing arrangement. 

The seal is only effective while the pump is operational: If the pump comes to a halt, an additional gland packing configuration will serve as a secondary stage of sealing, aiding in the containment of the slurry within the pump. The operation of the dry gland sealing arrangement is efficient and user friendly across many mining applications; it also offers cost effective and reliable field operation without the need of any additional water supplies.

‍Pump and Abrasion Technologies' dry gland configuration is offered in high-chrome as standard and yields a class-leading design both in the hydraulically optimized vane profile, thickness and efficiency. Due to the increased diameter ratio between the impeller and expeller, the Curve^® will achieve a greater sealing at higher suction pressures, further expanding the application of the dry gland seal option.

Wet Gland Configuration

The wet gland configuration consists of a full stuffing box containing several gland packings and requires the supply of gland service water to function properly. The gland service water continuously flushes the slurry back into the pump volume to ensure that the abrasive particles do not interact with the gland packing and shaft sleeve surfaces. 

The mating surfaces of the gland packing and the shaft sleeve provide the necessary sealing capability that is required to contain the slurry inside the slurry pump. The gland service water acts as a flush medium to remove contaminants and prolong the operational life of pump components.

Pump and Abrasion Technologies' wet gland configuration is offered in high-chrome as standard, ensuring an exceptional resistance to abrasion. Our wet gland sealing also removes the need for expensive clean water, as it can handle dirty gland service water with ease. The design allows for multiple lantern ring inlet holes in order for the gland service water to infiltrate, preventing sealing arrangement failures due to blockages. 

Mechanical Seal Configuration

The mechanical seal configuration offers complete pump sealing, both during pump operation and non-operation (i.e., while the pump is stationary). The mechanical seal is achieved by the close mating fit of two interacting surfaces that each have very tight mechanical tolerances. Due to the limit of the clearance/gap between the rotating and stationary seal components, the slurry is unable to pass through. 

The mechanical seal can satisfy most sealing requirements and eliminate pump spillage on a permanent basis. However, this performance comes at a price - the mechanical seal configuration is more expensive than the other detailed counterpart configurations and can incur drastic and fatal damage if it is not well maintained and monitored.

Choosing the Optimal Seal Configuration

All three types of sealing configurations are available with the Curve^® range of slurry pumps. The list of general applications detailed below illustrates which sealing configuration should be used for a given pump application.

• General Pump Configurations (e.g., single pump scenarios) – Dry Gland
• Series Pump Configurations (e.g., two or more pumps) – Wet Gland or Mechanical SeaPl
• Intermittent Pump Operation (several start-stop cycles per day) – Mechanical Seal
• Pump Applications where slurry cannot be diluted – Dry Gland or Mechanical Seal

The scenarios provided above are only but a few of the situations that are encountered in the field of pumps and pumping applications.

Case Study

PABT was requested by a Coal Client in the Mpumalanga area to assess a problematic thickener underflow application that experienced continuous slimming (slurry spillage emerging from the pump’s sealing arrangement) while operational. As a result of the continuous slimming, a build-up of slurry occurred around the pump and thickener area which required additional, unnecessary manpower to clean on a daily basis. 

The spillage onto the bearing assembly also threatened the integrity of the assembly and increased the risk of premature bearing failures due to slurry contamination. In an attempt to manage the problem and the rate of spillage occurring, the client implemented frequent gland packing and shaft sleeve replacements. Thus, recurring maintenance and cleaning were performed on an application that should not have required that much attention or frustration.

PABT determined that the installed competitor slurry pump’s expeller sealing arrangement was providing insufficient sealing capability to contain the slurry in the pump. The client gave PABT the objective of resolving the problem without implementing a mechanical seal or a wet gland. With our problem-solving mindset and innovative engineering, PABT recommended a Dry Gland (expeller) slurry pump, capable of handling the conditions of the application on a prolonged basis. 

Through thorough inspection of the application and sampling the necessary system data, we determined that the Curve^® SD150 pump with its enhanced sealing capabilities was best suited to satisfy the user requirements. 

The Curve^® SD150 pump was commissioned in May 2021 and has since been functioning without slimming. Not only has this led to increased plant neatness around and below the thickener, but it has also reduced the effort required to maintain the slurry pump, as well as increased the general reliability of the application. 

Conclusion

We take pride in delivering a wide range of impact-reducing products to meet the specific needs of our customers and achieve crucial objectives. Our advanced pump technologies ensure an extension of your slurry pump’s wear life and a dramatic reduction in Total Ownership Cost, power consumption, downtime, and the environmental impact - ensuring a sustainable future. Pump and Abrasion Technologies also offers unrivalled service, 24/7 for the lifetime of your Curve^® products. 

We Invite you to be a part of the future of mining with our revolutionary slurry pumping technology.

Get in contact with our pump system specialists for a customized solution to meet your pump system’s complex needs.