By Michelle Goldsmith, Contributing Editor, Mining Magazine
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In mining and ore processing operations, slurry pumps provide a vital means of effectively transporting slurry over any distance. Their running costs also contribute a significant component of total operating costs, and any failure of this key piece of equipment can bring a mining project grinding to a halt. Therefore, improvements in the sustained efficiency and reliability of slurry pumps can result in substantial bottom-line benefits to mining operators.
Despite their importance, the highly demanding nature of the application and the complex set of factors affecting slurry pump performance in mining operations mean that it is still relatively common to find pumps being operated inefficiently, or in ways that reduce equipment lifespan, resulting in lower overall efficiency and higher costs for the project. Maximising slurry pump efficiency requires the correct specification and selection of pumps, and ensuring that they are optimally operated to deliver sustained efficiency and reliability over the longer term.
Slurry pumps are required to transport large volumes of slurry, composed of target minerals and overburden suspended in a carrier fluid, to mineral extraction process plants for separation. Therefore, they must be able to handle the abrasive solids in the slurry and, in some cases, corrosive fluids.
Due to the nature of the material being pumped and the distances involved, slurry pumps are usually large and consume significant amounts of power. This is an extremely demanding application, and slurry pumps often operate 24/7, meaning that in severe conditions the wear life of wetted components can be only two to three months. Any failure or inefficiency in slurry pumping can have significant repercussions for the entire plant and project, impacting the overall profitability of mining operations.
Optimising the efficiency of slurry pumps over their entire service life requires:
♦ Specifying and selecting the right pump and other equipment for the application
♦ Ensuring the pump is operating at its best efficiency point
(BEP) flow rate
♦ Regular monitoring and maintenance to prevent unplanned outages and declining performance
To deliver maximum slurry pumping efficiency, the performance characteristics of the pump or pumps employed must be well matched to the unique requirements of the particular application on a project. If wrongly specified, even a pump that appears to be operating with a high efficiency can quickly become worn down and damaged. This can result in failure or other problems, like higher power consumption and shorter pipeline equipment life, that will negate the initial efficiency and, ultimately, incur higher costs over time.
The majority of slurry pump issues are caused by a mismatch between the pump’s performance characteristics and the application requirements, either from the initial specification or due to circumstances changing since that specification.
Two main types of pumps are regularly used for transporting slurries: centrifugal pumps and positive displacement pumps. Centrifugal pumps are usually employed for flow rates from a few litres to thousands of litres per second, and can handle solid particle sizes from microscopic to large rocks up to 300mm. However, they generally can’t develop pressures higher than 7MPa even when they are arranged in series. Their casings can be unlined or lined with internal replaceable liners, composed of materials appropriate to the features of the slurry. The wearing parts are mostly impellers, volutes and side liners.
Positive displacement pumps are often employed for pumping through very long pipelines, because of their ability to generate high pressures, which are well in excess of multistage centrifugal pumps. Their design flow rate range is limited from 50 to 1000 litres per second, due mainly to their large physical sizes, both at low and high flows. They are best suited to transporting slurries with high concentrations of fine particles with a maximum size of about 6mm. The maximum particle size is dictated by the poppet valves, which can jam in semiopen position by large particles. Poppet valves are high wear components that need to be replaced frequently.
An array of different factors come into play when it comes to choosing the best pump for the job. These include the pump’s best efficiency point (BEP), the characteristics of the slurry to be pumped, the distance the slurry must travel, and more.
Some of the most important parameters of slurries to consider when selecting a pump include:
♦ The particle size, shape (angular, round, long and stringy) and hardness
♦ Corrosiveness
♦ Chemical compatibility with elastomers
♦ Solids concentration
♦ Likelihood of running dry
A number of factors should be taken into account in order to select a centrifugal pump that matches the system and application’s hydraulic requirements. These include the system’s design, the required flow rate, the system resistance, and system curve.
System design – Oversizing or undersizing the pump for the application can result in the pump operating outside the range of its BEP or its allowable operating range. This can cause problems such as circulation issues, vibration, cavitation and loud operation.
Flow rate – The flow rate achieved in a pumping system is the result of the head created by the pump.
System resistance – The system resistance head is the head necessary to overcome the static head and the friction head in the pipeline. The duty point of the pump is the flow at which the head created by the pump is equal to the system resistance head.
Duty point (rated flow at differential head) – The key to successful pump selection is to accurately specify the required duty point.
The pump’s BEP flow rate is the optimum flow rate for the slurry to travel through the system at a particular impeller speed.
Net positive suction head (NPSH) is the total absolute head at the pump suction minus the vapour head of the pumped fluid. To prevent cavitation, and the resulting damage, the system net positive suction head available (NPSHA) must be greater than the pump net positive suction head required (NPSHR), preferably with an appropriate safety margin.
Determining the required flow rate, total dynamic head to be generated by the pump, and the suction lift or NPSHA, enables the selection of a pump with a performance curve that satisfies these requirements.
The performance curves provided by pump manufacturers indicate pump efficiency, power use, and the suction lift or NPSH required for the pump’s flow range. The speed (rpm) and input power (kW) required can then be determined by plotting the required flow, total head and suction lift on the performance curves. However, determining the requirements for slurry pumping applications is complicated by the variable individual characteristics of a slurry. The manufacturers’ performance curves are generally based on the process fluid being clear, cold water. Therefore, pumping a comparatively heavier or lighter fluid will require comparatively more or less power, and this must be taken into account in pump selection.
Other possible features of slurry pumps that could influence final pump selection include:
♦ Levelling (on/off control devices)
♦ Self-priming
♦ Thermal overload protection
♦ Non-clog
♦ Plug-in
♦ Reversible
♦ Dry-running capabilities
♦ Ease of maintenance
In reality, final selection is often a trade-off between high capital and low maintenance costs, or low capital and high maintenance costs. Therefore, the total cost of ownership over the pump’s service life and the duration of mining operations should be taken into account and balanced.
Once an appropriate pump is selected for a mining slurry application its sustained efficient operation requires that it remain in good condition. Among the key factors that impact upon pump wear is the flow at which the pump is actually operating in relation to its BEP flow rate.
Even a large, robustly built pump running at a slow speed can experience gouging and wear that reduces the lifespan of its components, subsequently reducing efficiency and increasing its lifetime ownership costs.
A pump operating at a high flow rate relative to its BEP often results in increased pipe friction losses, reduced efficiency, increased power, noise and vibration, high radial loads on bearings, and cavitation due to lack of NPSH available.
Meanwhile, when pumps operate at low flow rates relative to BEP, sedimentation and sanding can occur in pipes, causing blockages. Other problems that may occur include recirculation, increased noise and vibration, increased radial loads on bearings due to unbalanced volute pressures, reduced seal, bearing and impeller life, low flow cavitation, and temperature rise due to dissipated energy created by low efficiency.
Ideally, slurry pumps would be operated at 100 per cent of BEP flow, resulting in maximum efficiency and minimum wear. However, in reality this is not always possible. Nevertheless, ensuring pumps run as close as possible to BEP will improve their performance and service life, maximising efficiency and profitability.
In some cases, although a pump may be correctly specified prior to installation, changes in circumstances that result in changes to flow, such as slurry composition, can require it to operate further away from its BEP flow. Over time, even small changes can result in significant losses of efficiency and increases to wear.
As a result, to achieve optimised slurry pumping efficiency, it is important to undertake regular inspection and maintenance, and to evaluate how any changes to conditions that occur may affect the application requirements, duty point and pump BEP.
Slurry pumps are critical to mining and extraction operations, moving the extracted minerals and associated material to and throughout processing facilities. This demanding application can result in significant wear to pumps, which are required to be powerful and robustly built, and often require significant amounts of power. As a result, the pumps themselves and the power to run them contribute significantly to the overall costs of a mining operation, and improving slurry pumping efficiency can significantly increase profitability for operators within the industry. Maximising efficiency involves determining the requirements of a given slurry pumping application and choosing the right pump for the job (with a BEP well matched to the duty flow rates), operating it as close to its BEP as possible to increase efficiency and equipment lifespan, and undertaking smart monitoring and maintenance to sustain this efficiency over the longer term. By following these steps, operators can increase the likelihood that their slurry pumps will be performing efficiently and reliably for a long time to come, maximising return on investment, and keeping mining operations running smoothly and profitably.
When it comes to submersible slurry pumps, there are commonly encountered questions that deserve attention. In this piece, we will focus on one primary inquiry: "What is the typical lifespan of a submersible slurry pump?" However, before we proceed to answer this question, it is essential to grasp the basic concept and operational principle of submersible slurry pumps. This comprehension will allow us to offer a more accurate and thorough response.
1.What Is A Submersible Slurry Pump?
A submersible slurry pump is specifically designed for the extraction of sediment, particularly sand, from bodies of water. It was initially developed to overcome the limitations of traditional dredging methods in certain applications and operate efficiently underwater.
Dredging is the process of removing sediment, debris, or other materials from the bottom of water bodies like rivers, lakes, and harbors, with the aim of deepening the water or creating new channels. It plays a crucial role in various industries, including construction, mining, environmental restoration, and marine infrastructure development.
The OCEAN Pump brand offers submersible slurry pumps that are specifically engineered to tackle the challenges of extracting sand from underwater environments. These pumps can be fully submerged during operation, allowing them to work at greater depths and effectively overcome the limitations of surface-mounted dredging equipment.
The primary function of a submersible slurry pump is to generate powerful suction to loosen and extract sand from the bed, subsequently transporting it to a designated location through pipes or hoses. To achieve this, the pump inlet is equipped with a water gun or a bottom agitator impeller, ensuring the smooth suspension of the sand in the water.
OCEAN Pump’s submersible slurry pumps find wide application in various dredging projects, including beach nourishment, harbor maintenance, land reclamation, and channel deepening. They efficiently remove sand, sludge, clay, and sediments of varying sizes, providing robust support for a range of engineering tasks.
2.How Long Do Submersible Slurry Pumps Last?
A well-maintained and properly designed submersible slurry pump manufactured by OCEAN Pump can typically last for several years to over a decade under normal operating conditions. However, it is important to consider the abrasive nature of sand, which can gradually cause wear on the pump components, potentially affecting their efficiency and lifespan.
The average lifespan of a submersible slurry pump is influenced by various factors. These include the quality of its manufacturing, the operating environment, the maintenance condition, and the operational practices employed. OCEAN Pump, being a reputable brand in the industry, follows rigorous standards and conducts comprehensive testing throughout the design, material selection, and manufacturing processes. This commitment ensures that their products are constructed to withstand normal operating conditions and have an extended lifespan.
3.How To Extend The Service Life Of A Submersible Slurry Pump?
3.1 Optimal Selection of Submersible Slurry Pump
To ensure smooth progress in dredging projects, it is advisable to choose a submersible slurry pump specifically designed for sand excavation operations. When making your selection, it is crucial to consider important factors such as flow rate, head, and sand concentration in a comprehensive manner. This ensures that the chosen submersible slurry pump fully meets the specific operational conditions and requirements of your project. Before finalizing your decision, we encourage you to reach out to our knowledgeable technical team at OCEAN Pump, particularly Lingda Kong (WhatsApp: +86 185 6229 3317). Lingda Kong will provide detailed parameter requirements, including but not limited to the hourly sand production rate, working environment of the submersible slurry pump, extraction depth, pumping distance, and size of solid particles. Based on these specific parameters, Lingda Kong will recommend the most suitable pump model, ensuring an efficient and safe implementation of your project.
3.2 Maintenance Guidelines for Submersible Slurry Pump
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Establishing a regular maintenance plan is essential for ensuring the sustained and reliable operation of a submersible slurry pump over the long term. This plan should encompass various vital steps, including routine inspections, cleaning, and lubrication. During maintenance procedures, a thorough examination of all components of the submersible slurry pump body is necessary to detect any indications of wear, corrosion, or damage, and promptly address any related issues. In cases where severe component wear or damage is identified, timely replacement is crucial.
When the cumulative or continuous operating time of the pump reaches 2500 hours, it becomes necessary to inspect fasteners and seals, and consider replacing turbine oil and mechanical seals in the oil chamber as deemed appropriate. Furthermore, maintenance of the pump’s flow-through components is equally important. This involves regularly replacing vulnerable parts such as oil seals, impellers, agitator impellers, inner pump covers, and suction plates. By doing so, efficient operation and an extended service life of the submersible slurry pump can be ensured.
3.3 Optimal Operating Conditions for Submersible Slurry Pump
It is crucial to adhere to the recommended operating parameters when utilizing a submersible slurry pump. To prevent motor overload and minimize the impact of excessive pressure or temperature, it is essential to ensure that the voltage and current of the motor remain within the acceptable range. OCEAN Pump highly recommends the use of variable frequency control cabinets, which incorporate voltage and current meters for precise regulation of motor frequency. By promptly adjusting the frequency based on data indications, it becomes possible to control the flow rate and head of the submersible slurry pump. Operating the pump within the specified range not only helps prevent premature wear but also significantly extends its service life.
3.4 Guidelines for Proper Installation of Submersible Slurry Pump
To ensure that the installation of a submersible slurry pump aligns with the manufacturer’s requirements, it is essential to strictly adhere to the relevant guidelines. During the installation process, it is crucial to utilize the correct accessories, seals, and connectors to guarantee the safety and functionality of the submersible slurry pump. Prior to installing the unit, OCEAN Pump mandates a 0.2 MPa pressure test of the internal cavity and oil chamber of each motor for 5 minutes to confirm the absence of leakage.
Proper alignment between the submersible slurry pump and the pipeline system is of utmost importance to minimize stress and vibration. It is recommended to install a rubber hose at the outlet before connecting HDPE or steel pipes. Additionally, considering the volume and weight of the submersible slurry pump, it is necessary to design external supports that provide sufficient support and prevent excessive movement and strain.
By diligently following these steps, we can ensure the quality of the submersible slurry pump installation and guarantee its smooth and reliable operation.
3.5 Sediment Control
To maintain the stable operation and prolong the service life of a submersible slurry pump, it is crucial to implement necessary measures to effectively control the presence of water sediments and abrasive particles. While the submersible slurry pump is initially designed for fine sand, OCEAN Pump has developed a semi-open impeller with a maximum passage diameter of up to 60mm to accommodate larger particles, which performs well in dredging applications. However, to ensure the optimal functioning of the submersible slurry pump, it is still recommended for users to employ effective measures to control the size of sediments and slurry particles before the pump is put into use.
Specific methods may involve the use of sedimentation tanks or similar devices to efficiently remove larger particles before they enter the submersible slurry pump. By minimizing the amount of abrasive material that enters the pump, not only can wear on the pump be reduced, but its service life can also be significantly extended.
3.6 Ensuring an Adequate Power Supply for the Submersible Slurry Pump
For the normal and uninterrupted operation of a submersible slurry pump, it is essential to provide a stable and suitable power supply. The submersible slurry pump relies on electric power, with the motor’s rotation driving the impeller to create the required suction and pressure for pumping slurry. Therefore, it is crucial to verify that the power supply aligns with the manufacturer’s specifications.
Key factors such as voltage, frequency, and phase should meet the pump’s requirements. It is advisable to seek guidance from an electrician or electrical engineer to assess the compatibility of the power supply and make any necessary adjustments or installations. This ensures a consistent and dependable power source for the submersible slurry pump.
3.7 Effective Monitoring and Control Systems for Submersible Slurry Pump
The implementation of efficient monitoring and control systems can significantly enhance the performance and reliability of submersible slurry pumps. By utilizing various technologies and devices, operators can monitor crucial parameters such as flow rate, head, temperature, and vibration. These monitoring systems provide real-time data, enabling operators to promptly identify any irregularities or deviations from the desired operating conditions.
Furthermore, integrating a control system allows for remote operation and automatic adjustment of the pump’s performance based on changing conditions. This not only improves operational efficiency but also reduces the risk of human error. To determine the most suitable monitoring and control solution for the specific requirements of the submersible slurry pump and dredging project, it is recommended to consult with the manufacturer or a specialized control system provider.
By implementing an efficient monitoring and control system, operators can optimize the performance, reliability, and overall efficiency of the submersible slurry pump, leading to enhanced project outcomes.
By implementing an efficient monitoring and control system, operators can optimize the performance, reliability, and overall efficiency of the submersible slurry pump, leading to enhanced project outcomes.
3.8 Operator Training and Safety Measures
Ensuring the safe and efficient operation of a submersible slurry pump requires proper training for pump operators. It is crucial for operators to have a thorough understanding of the pump’s operation, maintenance procedures, and safety protocols. They should be well-versed in the potential risks associated with working with high-powered equipment and receive training in emergency response procedures.
To maintain operator safety during pump operation and maintenance activities, it is essential to provide adequate personal protective equipment (PPE) and ensure its proper usage. Regular safety audits and inspections should be conducted to identify and address any potential hazards or safety issues promptly.
By prioritizing operator training and implementing comprehensive safety measures, the risk of accidents and injuries can be significantly reduced. This not only ensures the well-being of the operators but also contributes to the overall efficiency and smooth functioning of the submersible slurry pump operations.
4. What Effect The Average Life Of Submersible Slurry Pump
4.1 Operating Conditions and Their Impact on the Lifespan of a Submersible Slurry Pump
The operating conditions in which a submersible slurry pump functions have a significant influence on its service life. Factors such as working pressure, temperature, medium properties, and sand concentration in the environment can greatly affect the longevity of the pump. Prolonged operation of the submersible slurry pump in harsh environments characterized by high pressure, high temperature, or corrosive media can lead to a shortened lifespan.
To address these concerns and ensure optimal performance and extended service life, OCEAN Pump has implemented specific design features. The inclusion of large passage impellers in their submersible slurry pumps allows for optimized pump performance. This design takes into account the working environment, enabling the pump to operate stably under various conditions. As a result, users can expect a more reliable and efficient experience from OCEAN Pump’s submersible slurry pumps.
4.2Design and Manufacturing Qualityof submersible slurry pump
The design and manufacturing quality of a submersible slurry pump are crucial factors that determine its service life. The design, material selection, and manufacturing processes all play significant roles in ensuring a longer lifespan for the pump.
OCEAN Pump places great emphasis on high-quality design and manufacturing practices. They carefully design their submersible slurry pumps and select materials that meet stringent standards. The overcurrent components of the pump are made from high-chromium alloy with a chromium content of 26%-28% and a hardness level of HRC≥65. This high-quality material offers exceptional corrosion resistance and remarkable wear resistance, making it an optimal choice for sand dredging pumps.
By utilizing such high-quality materials and implementing rigorous manufacturing processes, OCEAN Pump ensures that their submersible slurry pumps are built to withstand the demanding conditions of sand dredging operations. This commitment to quality design and manufacturing ultimately extends the service life of the pump, providing users with reliable and durable equipment.
4.3 Maintenanceof submersible slurry pump
To ensure the long-term and reliable operation of a submersible slurry pump, it is highly recommended to conduct regular professional maintenance. This maintenance routine should include tasks such as replacing worn-out parts, adjusting clearances, and cleaning filters. By adhering to these maintenance measures, the service life of the pump can be effectively extended, ensuring its continued stable performance.
OCEAN Pump is dedicated to providing comprehensive support for their products. They offer detailed operating instructions for all their submersible slurry pumps, available in multiple languages to cater to the diverse needs of customers worldwide. Recognizing the value of their customers’ time and interests, OCEAN Pump regularly reminds customers to change the oil at appropriate intervals to ensure the smooth operation of the submersible slurry pump.
With a commitment to exceptional customer service, OCEAN Pump promises to deliver 24/7 online pre-sales and after-sales support. Their team is readily available to answer any inquiries and provide professional technical assistance. By choosing OCEAN Pump, customers not only gain access to high-quality products but also enjoy worry-free after-sales support.
4.4 Operation Conditionsof submersible slurry pump
To ensure optimal performance and maximize the service life of a submersible slurry pump, it is crucial to adhere strictly to the designated operating conditions outlined in the pump’s specifications. Deviating from these operating conditions can result in issues such as pump overload and accelerated wear, ultimately shortening its lifespan.
At OCEAN Pump, we prioritize a thorough understanding of our customers’ working conditions before assisting them in pump selection. A key consideration is the customer’s sand extraction requirements. The flow rate of the submersible slurry pump is typically calculated based on the mixed flow rate of sand and water, with a sand concentration ranging from 30% to 50% of the mixed flow rate. In some cases, the sand concentration may even reach 60%. Additionally, we take into account the customer’s dredging depth and discharge distance requirements, as these directly determine the required lift head or working pressure of the submersible slurry pump. It’s important to note that there is an inverse relationship between flow rate and head: as flow rate increases, head decreases, and vice versa. This means that a submersible slurry pump can meet different parameter requirements simultaneously, but a higher flow rate corresponds to a shorter discharge distance, and vice versa.
Furthermore, the speed at which the submersible slurry pump operates is a critical parameter. Customers should ensure that the pump operates within the specified speed requirements to avoid negatively impacting the pump’s service life.
By carefully considering and adhering to these operating conditions, customers can optimize the performance and extend the service life of their submersible slurry pump.
4.5 Electrical System of thesubmersible slurry pump
Maintaining the electrical system of a submersible slurry pump, which includes the motor, cables, and control equipment, is crucial for ensuring optimal performance and extending the pump’s service life. Any faults or issues in the electrical system can lead to unstable pump operation, resulting in a shortened lifespan.
At OCEAN Pump, we provide specially designed motors for submersible applications. These motors feature a vertical structure and are equipped with 1-2 sets of built-in mechanical seals, ensuring the safe and reliable operation of the motor. To further enhance motor performance and longevity, we recommend the use of frequency control cabinets. These cabinets offer effective protection for the generator set and motor during startup, ultimately extending the motor’s service life.
To ensure the overall safe operation of the submersible slurry pump, we have implemented three protection systems. The first is motor overheating protection, which safeguards against excessive heat buildup. The second is motor oil chamber water ingress protection, which prevents water from entering the motor’s oil chamber. Lastly, we have motor overload protection, which prevents the motor from operating beyond its capacity. When any of these protection systems are triggered, the submersible slurry pump immediately stops working, allowing for maintenance by trained personnel. These enhancements not only enhance the safety of the pump but also effectively improve its overall service life.
By maintaining the electrical system in excellent condition and utilizing our specialized motor design and protection systems, customers can ensure the safe and reliable operation of their submersible slurry pump while maximizing its service life.
4.6 Installation And Commissioningof Submersible Slurry Pump
The installation and commissioning process of a submersible slurry pump play a critical role in determining its service life. Only when these steps are carried out correctly can the pump maintain normal operation and avoid premature wear and malfunctions caused by improper installation. At OCEAN Pump, we prioritize product quality and conduct rigorous installation and commissioning processes before our pumps leave the factory.
The initial step involves installing and commissioning the control system. This ensures that all circuits are correctly connected and powered on, allowing us to observe the rotation of the submersible slurry pump impeller and verify its proper functioning. Subsequently, the pump is securely fixed on the foundation or pontoon in accordance with the installation requirements. The inlet and outlet pipes are then connected, and the submersible slurry pump is properly aligned with the pipeline to ensure a smooth flow of materials. Finally, the power supply is connected, and a thorough operational test is conducted to ensure the pump is functioning as intended.
To assist customers with the installation and commissioning process, we provide detailed instructions that guide them through each step, ensuring the correct installation of the submersible slurry pump.
By giving careful consideration to these factors and addressing them during installation and commissioning, the service life of sand dredging pumps can be effectively extended. OCEAN Pump is dedicated to delivering high-quality products, professional technical support, and comprehensive after-sales services to meet the diverse needs of our customers and ensure their utmost satisfaction.
In summary
The lifespan of submersible slurry pumps is influenced by various factors, including their quality, maintenance routines, operating environment, and patterns of use. These pumps are specifically designed to withstand the demanding conditions encountered in mining, construction, and dredging applications.
When submersible slurry pumps are properly maintained and serviced regularly, they typically have a lifespan of several years to a decade. However, it’s important to note that these estimates are approximate, and the actual lifespan may vary depending on specific circumstances.
To effectively and efficiently utilize submersible slurry pumps in dredging projects, it is essential to consider several key factors. These include selecting the appropriate pump model, implementing regular maintenance practices, ensuring optimal operating conditions, proper installation, sediment control, reliable power supply, utilizing monitoring and control systems, and providing operator training and safety measures. By following these guidelines, the pump’s performance, reliability, and lifespan can be maximized, leading to smooth and successful dredging operations.
Lingda Kong
Tai’an Ocean Pump Co.,Ltd
The company is the world’s best tah slurry pump factory supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.