Hydraulic

WHAT TO LOOK FOR IN A HYDRAULIC SUBMERSIBLE PUMP

Rental Tools Online offers many types and sizes of portable hydraulic pumps from different manufacturers. If you are not sure which type of pump you need or what specifications are important, this may help.

BODY (VOLUTE) MATERIAL

There are three typs of materials you will find among our pump selection: Urethane, Aluminum, and Iron.

• Urethane bowls are very lightweight and can do a good job with clean, clear water. It is not recommended for water that has a lot of abrasives in it as these will eventually deteriorate the tolerances between the impeller and volute causing a reduction in performance. They are not as long lasting if used for pumps with potential solids, like trash or sewer pumps. 


• Aluminum is a great alternative to urethane. Although it is not as light as the urethane plastic, it is signifcantly lighter than iron and is much more abrasion resistant than urethane. Aluminum is generally better for use in salt water and corrosive liquids as it is inherently more corrosion resistant than iron. It is not as impact resistant as iron however, and may crack with a significant impact to the housing.


• Iron has been used for pumps for well over 100 years. It is tough and unlikely to distort under different temperature and pressure conditions. It is also very abrasion and impact resistant and is ideal for sandy environments. 

IMPELLER MATERIAL

Similar to the volute, there are different materials employed for the impeller. In a centrifugal pump (which all these are) the impeller is the part of the pump that spins around inside the pump body, flinging the liquid from the center, outward towards the discharge port. It is important to select the right impeller material for the type of job at hand.

• Urethane impellers are very good for the same types of conditions as urethane bowls: cool, clean, clear water. The water should be less than 100 degrees or so to avoid distoring the shape of the impeller. It is not recommended for pumping solds as these can cause the plastic to crack or break.


• Stainless Steel is the ideal choice for salt water or other corrosive liquids. It is very stable under different temperatures and pressures, and will usually be unaffected by pumping smaller solids. 


• Iron is normally the best choice for abrasives and larger solids. 

YOU CAN'T GET MORE OUT THAN YOU PUT IN

Some manufacturers claim to get much higher flow rates and head pressures from the same hydraulic oil input flow rates and pressures as other manufacturers. The equations are complex, but the idea is simple. It takes a certain amount of energy to move a volume of water to a particular height; it just does. The power going in to the pump has to be somewhat higher than that to compensate for friction loss, heat, and so on. There may be some efficiency improvements gained by impeller or volute design, but these are not normally as significant as some manufacturers claim. Beware of numbers that are too good to be true!