Which Hydraulic Pumps are the Best?

The most important component of a hydraulic system – its heart, so to speak – is undoubtedly the pump. Understandably, as pump specialists, we are asked many questions about hydraulic pumps in particular.

We answer some of these questions in this article.

Three specific questions.

One question that recently reached us was:
"Can even small, compact pumps move large volumes? We are skeptical about that ...?!"

Also very specific was this customer inquiry:
"Can your pumps move hydraulic oil in such a way that the lubricating film does not break off?"

And last but not least:
"We work with fluids over a wide viscosity range. Unfortunately, we have had bad experiences with other pump technologies. Do you have better solutions?"

Our answer to all three questions is unequivocal: yes.

Have you also worked with other pump technologies so far or are you undecided which pump is best suited for your application?

Find out what you should look out for in the following overview.


Can small pumps handle large volumes?

Well, with pumps it's much the same as it often is in life: Don't be fooled by appearances. The true values are hidden inside.

Hydraulic pumps can be small and compact and still deliver large quantities. It is precisely this high power density that characterizes our screw pumps. They can also be installed in areas where space is at a premium. At the same time, they ensure a continuously high flow rate over a wide viscosity range.

In fact, the screw pump is often the only possible solution due to its combination of compact design, high flow rate and quiet delivery.

Here is an example from our practical experience:
In the factory of a well-known international automobile manufacturer, a hydraulic pump was installed which, due to local noise regulations, was not allowed to exceed the limit of 75 dB. At 78 dB, the KRAL hydraulic pump was only just above this, and was brought below the prescribed limit by means of an appropriate casing. This was only possible because the pump operates with low pulsation and is therefore quiet. Because it is so compact, there was sufficient space for the casing. Other pump technologies would not have been able to meet these requirements due to its technically induced noise development and its size.

Other hydraulic applications for which screw pumps are the better long-term choice.

Hydroelectric power plants:
Hydraulic pumps are needed to reliably raise rotor and generator shafts when a turbine starts up. Screw pumps have proven their worth here – they also reliably handle rapid pressure increases. 

Thermal power plants:
In thermal power plants, the potential efficiency of the plant is often not optimally utilized. Unlike other pump solutions, screw pumps offer the advantage of optimum efficiency for a wide range of viscosities, even with fluctuating pressures.

Wind turbines:
In order to optimize generator efficiency in different weather scenarios, hydraulic pumps are required to adjust the rotors with absolute safety and reliability.

In marine applications, hydraulic pumps are used for windlasses, steering gears, propeller adjustments and turbine bearing lifts. The advantages of the screw pump are again the small space requirement, the gentle delivery and the high reliability.

In summary, we hold that KRAL hydraulic pumps have convincing advantages for many applications. Among other things, because they:

  • pump hydraulic oil for long periods without the influence of air
  • can deliver large quantities with a small footprint
  • deliver the oil linearly, i.e. axially
  • have a high degree of efficiency
  • have hardly any heat input and little backflow
  • cover a wide viscosity range
  • are very quiet
  • cause minimal wear
  • are very easy to maintain and have a long service life
  • maintain the quality of the oil

Hydraulic pumps are among the most important components of a hydraulic system. Which pump is best suited for your needs depends on the purpose for which it will be used, the pressures, viscosities and quantities being worked with, differential pressures, flow rate, location, space requirements, noise regulations and more.

Screw pumps are particularly suitable when large volumes have to be moved, as they are absolutely reliable.

We deliberately specialized in this pump technology 50 years ago and have in-depth knowledge and many years of experience. There is hardly any application, no matter how special, that our technicians have not yet seen.

In addition, KRAL is known for its exceptionally fast service throughout the industry. Our pump experts respond quickly and without complications. The expertise of our specialists ensures the high quality of products and services.