Equally, it is a decision that applies to the choice of dewatering pump technologies for operations within the construction, mining, utilities and municipal arenas.
However, unlike the automotive debate, it is not a contest of technical supremacy to establish an outright winner. It is a common-sense selection process based on matching equipment performance and capability to all aspects of dewatering applications. Any decisions should take into account critical factors such as required volume, flow/head specifications and the constitution of water and materials to be pumped. Pump capability has to encompass the variables of operational conditions, site access, project duration, environmental issues, equipment autonomy and much more.
Sturdily built for endurance and reliability, diesel powered centrifugal pumps are designed for handling high volumes of water discharge. The operating flow range is typically between 50 to 830 m3h (220 to 3,654 US gpm) with a head of up to 51 metres (167 ft). In addition, these pumps are able to operate in a variable speed range, which enables them to cover different applications and flow/head combinations.
By comparison, medium-to-large electric submersible pumps offer maximum power ratings in the region of 80 kW and can typically manage flows up to 20,000 liters per minute (5,283 US gpm) with a maximum head of 85 metres (279 ft). These are the typical range; however, some higher-head pumps are available.
Diesel powered centrifugal pumps can handle larger solid particles.
Submersible pumps are available in variety of performances.
Diesel driven centrifugal pumps can work with water that is clean or dirty as well as handle trash and fibrous materials. Their solids handling capacity can reach up to 76 mm (3 in) in size thanks to features such as semi open impellers and abrasion-resistant pump casings. Discharge connection diameters typically range from 75 – 200 mm (3 - 8 in).
In contrast, electric submersible pumps have the ability to handle abrasive materials and solids up to 12 mm (0.5 in) (higher with sludge pumps), although it’s highly recommended to equip them with hardened impellers when handling suspended solid.
Electric submersible dewatering pumps offer portability, easy handling and are generally available in a power rating and capacity range that make them well suited to ground water control applications; including emergency duties. For instance, construction and mining sites where a pump with a small footprint is needed, such as when draining a sediment tank. They are also useful for applications where diesel pumps cannot be used, for example underground mining or where emissions are not allowed.
On the other hand, fully automatic self-priming diesel centrifugal pumps are the de facto choice for delivering fast dewatering solutions to sites where an alternative power source, such as a generator or mains feed, is not available. They are the ideal solution for transporting or raising water with large abrasive solids in suspension; such as in construction and quarry site dewatering, floodwater, stream diversions and municipal applications. Transportation and storage handling at remote sites is simplified if these pump units feature forklift slots and a built-in lifting eye.
Portability, easy handling.
For applications where emissions are not allowed
Fast dewatering solutions for water with large abrasive solids in suspension, where an alternative power source is not available
Providing hours, and even days, of unattended dewatering pump operation, submersible pumps can meet the demanding requirements of raising water from great depths or lowering water tables even in the toughest environments; with some models capable of running for up to 2,000 hours without attendance and designed for sustaining dry running. As they are sub-surface units they can continue working under ice in freezing conditions; as long as the pump is completely submerged. Where appropriate to the task, electric pumps offer environmental compatibility. For instance, quiet running is an essential feature of their performance when they are sited in populated areas or employed in night-time operations.
When equipped with a reliable engine and high capacity cooler, centrifugal pumps will ensure continuous and safe running even at high ambient conditions. Together with fuel autonomy of around 40 hours, continuous drainage is made possible even with significant volumes of air (snore conditions) thanks to an oil-free diaphragm vacuum pump’s automatic priming. In addition, some pumps can be equipped with an extra-large fuel tank that allows them to run for longer periods without refuelling
With electric submersible pumps extreme durability is guaranteed as they offer high-wear resistance. Meanwhile, the modular construction of these types of pump provides for simplified maintenance procedures. Some models can also be equipped with on-site servicing and parts replacement kits, including seals and impellers.
With the exception of replacing wear parts and engine filters, maintaining centrifugal pumps is easy and simple. Another part of this type of equipment’s appeal to rental organisations is the inclusion of advanced controllers with data monitoring capabilities that flag up when service interventions are required.