Best Practices for Submersible Hydraulic Pumps Selection
May 15, 2020
How Submersible Hydraulic Pumps Outperform Other Artificial Lift Technologies
If you’re looking for a construction solution that requires a submersible pump you may be wondering if it’s better to use an electric motor-driven or a hydraulic pump. Since the purpose of a pump is to transfer liquids, the properties of the liquid being pumped are a key factor when choosing the right pump. Things to consider include:
- Acidity/alkalinity (pH) and chemical composition
- Specific gravity
- Vapor pressure
- Solids concentrations and particle sizes
A hydraulic submersible pump (HSP) set is a two-piece system that incorporates a hydraulic power unit that’s equipped with a hydraulic pump, a hydraulic oil reservoir, and connections for hydraulic hoses, with a submersible trash pump.
Since hydraulic submersible pumps are powered by pressurised fluid as opposed to suction, they offer a powerful and efficient solution when high heads or high lifts are required on job sites that require pumping in deep excavations, manholes, open pits, quarries, or mines.
The simplicity and flexibility of these pumps means they’re well-suited to a wide range of artificial lift duties, including onshore and offshore applications. Construction contractors, public works departments, and mining companies will often use hydraulic pumps when suction can cause problems in jobs such as dewatering gravel pits, mines, quarries, trenches, and pipelines.
Physical restrictions, like friction and atmospheric pressure, put limitations on suction lift on depths that exceed 25 feet, whereas, submersible hydraulic pumps separate the pump from the engine, permitting pumping from depths of down to 450 feet.
Another advantage to using hydraulic submersible pumps is that they can handle viscous liquids like sewage, sludge, slurries or muddy water without the clogging problems that can occur in suction pumps.
Hydraulic Submersible Pumps vs Electric Submersible Pumps
Electric submersible pumps are a popular choice for many industrial jobs and are often used for oil lift applications, particularly offshore pipeline access. However, that doesn’t necessarily make them the best choice as these pumps are known to fail for a number of reasons including:
- Electrical failure in a wet environment
- Overheating of the downhole electric motor
- Exceeding the limits they were designed for
- Being unsafe in hazardous environments
Hydraulic submersible pumps differ from other artificial lift technologies for a number of reasons.
Since the HSP has no electric motor and a very wide operating envelope, it allows variable engine speed for different flow rates and heads to suit different job conditions, from mine sands to vicious fluids.
Elimination of Failure
The HSP design eliminates failure because the power fluid used to drive the turbine delivers a positive, outward clean flush to the pump end bearing system. It’s also assembled on a single, high-precision shaft, removing the need for motor-pump coupling at the well site.
Heavy Oil Applications
Heavy oils, particularly those with an emulsion-forming propensity that could considerably increase fluid viscosity, can create major flow problems. However, the HSP has an “open loop” power fluid supply configuration. This allows high viscosity fluids to mix with the power fluid and create a water-continuous dispersion downstream of the HSP and reduce friction losses.
Multiphase mixtures are not an uncommon occurrence at oil wells because free gas is often co-produced. Unfortunately, the presence of free gas at pump suction can harm the hydraulic performance of pumps. Having helico-axial design multiphase impellers and a constant power turbine drive gives the HSP a variable speed operating capability when it faces variable-density fluids within the pump end.
When there are problems with corrosion, chemicals can be added through the power fluid supply at the surface facility. Heated power fluid can be used to artificially increase the temperature of this fluid to prevent gelling in fluids with low wax-appearance temperatures. The open loop HSP power fluid system can circulate out hydrocarbons from all flow paths above pump setting depth to avoid restarting issues.
Canada Pump and Power manufactures, sells and rents their own line of industrial pumping systems. Mighty Pumps are purposely built for heavy industrial use, efficiency, extreme weather and mobility and are well-suited for a variety of applications including: water, wastewater, solids handling, slurry, dredging. Mighty Pumps automatically and continuously prime and are complete with a remote monitoring system, so that you always know where the pump is and what it’s doing.
You may think that renting is the better option because it means never having to deal with pump repairs. However, for some industries, purchasing a submersible hydraulic pump can be more cost effective. Mighty Pumps are built to the highest quality industry standards and are able to pump more, prime faster, last longer, and are easier to monitor than most other pumps. CPP’s team of experts can advise you on the best solution to your pumping problem.