Large submersible water pumps for infrastructure

The South African government is making a concerted effort to make clean drinking water available to everyone. In addition, as more people move to the big cities and industrial centres grow, there is pressure on engineers and managers to move water to high usage areas. Large scale pumping systems, often custom-engineered, are needed to deliver clean potable water, for new commercial developments and infrastructural projects.

This article delves into key aspects of large capacity water pumps and systems and provides insights for both technical experts and decision-makers, including:

• Problems typically experienced in South Africa

• Engineering factors to consider

• An example of a custom-built large capacity water pump system

Large capacity water pumps are used for:

• Bulk government water infrastructure projects

• Large scale residential water movement projects

• Water treatment plants

• Municipal potable water bulk management

• Water reticulation for new dam reservoirs

• Flood and stormwater management

Problems Engineers and EPC’s in South Africa typically experience when procuring new water pump systems:

Long Delivery Periods

Projects can be held up by manufacture and delivery times from overseas being overly extended.

Deviation from Specifications

Some manufacturers make changes as they manufacture, too much deviation from the specifications, can result in lesser quality and longevity of the pump.

Inefficient Pumps

Pumps that deviate from high quality standards have higher electricity costs.

Pump Maintenance

Difficulties obtaining spare parts and extended downtimes can result if the pump is not of the required quality. To avoid these pitfalls, it’s important to ask the right questions and consider these issues early in the procurement process.

Engineering factors to consider when selecting large submersible water pumps

Designing and implementing a large capacity water pump system takes careful planning.

Hydraulic Analysis:

Accurate calculations of these requirements:

• Head loss

• System curves

• Pump operating points

Pump Selection:

Matching the pump’s performance characteristics to the system requirements:

• Flow rate

• Head

• Efficiency

Evaluating these factors to prevent cavitation:

• Net Positive Suction Head Required (NPSHr)

• Available Net Positive Suction Head (NPSHa)

System Design:

These factors can significantly impact energy efficiency and system reliability:

• Optimizing pipe sizing

• Minimizing bends and fittings

• Strategically placing pumps in series or parallel

Energy Efficiency:

Given the high energy consumption of these systems, engineers must prioritize:

• Energy-efficient pump selection

• Motor drives (e.g., Variable Frequency Drives – VFDs)

• System design to minimize operational costs.

Reliability and Redundancy:

Implementing backup pumps and robust control systems ensures continuous water supply even during maintenance or equipment failures.

Maintenance and Accessibility:

Designing the system with ease of access for maintenance and repairs is vital for long-term operational efficiency. Well known water pump supply companies, such as Ebara, have engineers with in-depth knowledge. They will help with technical information.

Advancements in pump technology

New pump technology, control systems, and data analytics are continuously improving the performance and management of large capacity water systems.

Advanced tech can have impact:

• The amount of energy a pumping system uses

• How easy the system is to operate,

• Maintenance downtime and costs

Leading pump manufacturers will invest in R & D and innovate with smart sensors, predictive maintenance software, and advanced control algorithms.

Example of a custom-built large capacity water pump system

Ebara has engineered and supplied some of the world’s most advanced pump systems.

Ebara Specialised Pumps Solution:

• Ebara Custom vertical-shaft, mixed-flow, multi-stage pump – pumps water from 67 m below the surface, total underfloor length of 88 m

Ebara Custom Submersible motor pump – pumps water from 100 m below the surface, features a unique double-suction, single-stage structure for the impeller, to increase rotating speed and achieve superior suction and a high pump head. Output of 3351 HP (2500 kW).

Ebara Pumps,

+27 (0) 73 090 2454,

ebara.epsa@ebara.com,

www.ebara.co.za