When determining what pump is best for an application, there are a number of factors to consider, such as flow requirements, head conditions, suction requirements and dimensional limitations. Hydraulic submersible pumps are an option that gives the added benefit of run dry capability, especially when electric-powered pumps are of concern because of potential electrical hazards or because diesel-driven centrifugal pumps are not an option due to suction lift restraints. Hydraulic submersible pumps are very versatile and can fit in a number of applications.
Hydraulic submersible pumps are available in various discharge sizes from a few inches to a few feet. Also, depending on the material and pump capacity requirements, the impeller design includes vortex, trash handling, mixed flow or axial flow impellers. Being submersible, this eliminates suction lift limitations of conventional diesel-driven and suction centrifugal pumps.
A Griffin 6-in. hydraulic submersible pump
unwatering a lake at 1.01 million gal per day
in Orange County, Calif.
Some of the applications in which these pumps are used include bypass pumping from a manhole or open pit, jetting wellpoints into sandy soils, transferring sludge materials from pits or even mixing purposes.
In open sump pumping, hydraulic submersible pumps are a good choice due to the high volume and high head capability. They are lighter weight than conventional electric submersible pumps, allowing for easier placement in sumps.
In bypass operations, the selection of equipment is often dictated by the available opening on the manhole. Historically, manholes were constructed with 22-in. rings and covers. In order to set a pump in the manhole, it was often necessary to cut the cone off and then repair at the end of the project. Because of the slim design, a 4-in. material handling pump can fit through this opening and eliminate the need for this step. This is extremely useful in applications where there is limited access or time is critical to get in and out of the job.
One of the most useful models for this application is a 4-in. material handling pump. This pump is about 18 in. in diameter and weighs about 210 lb. It has a top tangential discharge. The impeller is an open vortex impeller that allows for the passage of trash and stringy solids. High head models are also available when higher pressures are required (i.e., deep setting or long discharge lines).
For heavy sludge materials such as drilling muds, the material handling pump is very good at overcoming the flow resistance and transferring the fluid. A good example is where casings are being drilled and the hole is stabilized with drilling mud. The pump can be used to transfer the drilling mud into the hole from the tank, and then used in the hole to circulate the mud, and then transfer back to the solids control equipment.
Overall, hydraulic submersible pumps are a good option in a number of applications because of their size, performance and flexibility in installation.