How a Warman® SHW submersible slurry pump can overcome the most aggressive dewatering challenges

Elevator pitch:
Warman® SHW submersible pumps are available with a variety of features to assist mining operations overcome many challenges associated with their heavy-duty slurry pumping or transfer applications.

Standfirst:
Tired of your operations being disrupted by unreliable submersible slurry pumps? We explore how the versatile Warman^® SHW provides reliable submersible dewatering in the most aggressive mining applications.

Body Copy:
Varying fluid levels, changing slurry consistencies, mineral types and even the beneficiation chemicals present can significantly impact the performance and wear life of your pump. This transforms what should be a reliable, low maintenance piece of equipment into something that not only demands significant time to repair, but also has a negative impact on your bottom line due to part replacements and production downtime.

Issues commonly affecting submersible pumps include moisture intrusion into critical internal electrical or lubricated components, abrasive wear of wetted components, impellers clogging due to particle size or slurry fluid composition, and insufficient slurry feed flows that causes overheating and cavitation.

In this article, we explore the root causes of these problems, and how different features allow the heavy-duty Warman® SHW submersible slurry pump to provide reliable dewatering in almost any application.

If your submersible slurry pump regularly goes into a failure state, there’s a good chance it’s because slurry has penetrated the motor housing or seal chamber. There are a number of ways you can prevent this from occurring and reoccurring, whether the fluid intrusion is due to the pump’s housing, the wear materials being unsuitable for the slurry it’s processing, or incorrect mechanical seal selection.

Leverage the right wear materials
In the case of a general failure in the pump casing, this is likely due to the wear material being unsuitable to withstand some aspects of the slurry being pumped - either the abrasive qualities of the particles contained within or a corrosive property of a chemical that was introduced at some point in the beneficiation process.

Without changing the slurry composition or processing method, the only real way to resolve these problems is to ensure that you’re using a heavy-duty submersible slurry pump with wear materials especially designed to meet the challenges of your application. For example, the Warman^® SHW has specifically been built for the most demanding submersible pumping applications, with a heavy-duty, all high-chrome (A05) wet end.

Ultrachrome^® A05, is proprietary high chrome white iron designed by Weir Minerals to provide a long, dependable service life in highly abrasive applications. The Warman^® SHW casting material can be selected to meet the needs of specific applications with different wear factors, such as in copper ore processing and other corrosive applications.

Use mechanical seals to prevent leakage
Most of the failures of submersible pumps can be attributed to a mechanical seals failure; a failure in the seal will permit moisture ingress to the electric motor and components, causing major electrical and mechanical damage to both the electric motor’s stator and rotor. Finally this causes the pump to stop operating, requiring an expensive, time consuming repair process that often requires specialist expertise.

The Warman SHW pump’s double mechanical seal arrangement not only prevents slurry leakage into the motor, but only exposes a minimal wear area to the slurry. The Warman^® SHW’s balanced double-seal arrangement encloses both sets of seal springs in an oil reservoir, which means the silicon carbide seal faces are only subjected to the submergence pressure, greatly increasing the wear life of the pump.

A moisture detector protects the motor and mechanical seal
When leakage can’t be prevented, the best way to manage a pump is to use a moisture detector which will automatically shut off the pump when moisture makes its way into the motor. The Warman^® SHW pump uses a twin electrode system that provides double protection, by detecting intrusion in the motor housing and the chamber of the mechanical seal.

Once detected, the Warman^® SHW shuts off the motor to prevent pump failure and raises an alarm to let operators know that maintenance is required.  The pump’s T-bolt construction makes gaining access to the wet end simple, allowing rapid disassembly of the pump for quick maintenance.

Preventing cavitation and overheating
Constant submergence plays a critical role in cooling the motor and preventing over-heating of submersible pumps. If the flow of water to the sump is interrupted, the pump’s motor is at risk of overheating or cavitating, which in turn decreases its efficiency and may lead to permanent damage or even complete failure.

While this generally isn’t an issue for static, shore-mounted pumps, the changing water level of submersible pumping applications can quickly lead to the pump running dry.

To manage this, all Warman^® SHW pumps feature winding thermostats that protect the motor by sending a signal to a relay supplied to the customer. This relay can be used for sounding an alarm or shutting down the unit if internal temperatures exceed safe operating limits due to a lack of water.

In applications where the fluid level varies significantly, the Warman^® SHW can optionally be outfitted with a cooling jacket, which enables continuous operation of the pump while the motor is not completely submerged by enclosing the motor housing with coolant.

Clogging
In high solids slurry applications with larger solids particles, submersible pump impellers are prone to becoming blocked by larger particles which prevents fluid from flowing smoothly through the pump. Without this consistent flow of fluid, the pump is at risk of overheating, cavitating and ultimately failing.  

In these high solids applications (up to 50% by weight), the Warman^® SHW suction saver prevents tramp material and large solids from blocking the impeller through the installation of a wear-resistant filter mesh at the bottom of the pump.

The ultimate heavy-duty submersible slurry pump
Through Weir Minerals’ global footprint and large Warman^® pump install base, Weir Minerals engineers have developed a unique understanding of how to optimise submersible slurry pumps for a variety of slurry applications and sump types.

As a solutions company, we don’t sell pumps without first visiting the site, understanding the application and slurry characteristics, and ensuring that we’re providing an optimised solution that will deliver efficient and reliable operation for as long as possible, with as little maintenance as possible.  

In addition to providing the right pump for the job, we’re committed to supporting our equipment to maximise its lifespan via our global network of more than 150 locations, which ensures that we can deliver the pumps, parts and expertise when it’s needed most, no matter where your mine might be

Call to action: With their proven reliability and robust wear resistance, Warman^® SHW submersible slurry pumps are designed to reduce maintenance and reduce total cost of ownership. Contact us today to discover how Warman^® SHW pumps can improve your operation.