Engineering a Quieter Power UnitHydraulic Power Unit

This was a Hydraulic system that we designed for a customer of ours who is a builder of Cutting Presses, to serve the Automotive, Carpet, and Home Cleaning Products markets, to name a few.  The noise level specification below 75 dba is fast becoming a prevalent requirement, as manufacturers increase their focus on the machine operators environment, as well as the plant environment in general. A typical hydraulic system operating at these flow rates and pressures can easily approach 85 dba.

The parameters were: 

  1. 400 Ton Cutting Press
  2. 75 GPM
  3. 3000 PSI
  4. Noise level < 75 dba

WATCH: Engineering a Quieter Power Unit

To give some reference to different sound levels, see the chart:

70 dba


Television set on loud, vacuum cleaner, several people on the telephone

75 dba

Constant sound

Busy restaurant around lunchtime

80 dba


Alarm clock, freight traffic, doorbell

85 dba


Sawing, mixer, Industrial machinery

hydraulic power unitLooking at design considerations that help to remove or redirect the noise away from the operator, while maintaining a cost-effective solution, is something that our engineering staff has to keep in mind for each and every application. While the use of Servo and Variable Frequency drive technology is developing, and the reduction of noise is a natural byproduct of that technology, it still remains a higher cost solution. As we see the cost for these technologies beginning to decline due to competitive pressure due to more global acceptance, it remains an option that most OEM’s just aren’t yet willing to pay for. As such, we are forced to find other ways to succeed.

In this application we utilized a foam, egg crate shaped product that absorbs sound, and is applied to the inside surface of the enclosure. Simultaneously, we designed the enclosure to force the noise upward, which allows the noise to dissipate naturally and is directed away from the operator. You can see in the picture the foam material applied internally. You will notice that there is no venting on either of the four side walls. However, venting is critical in keeping the overall system cool. Therefore, the venting only exists in the top above the motor and the cooling fan as well as below the cooling fan. This allows us to pull cool air from floor level and circulate that through the heat exchanger and around the rest of the system, while directing noise up and down only. The result was that we were able to achieve a sound level of 73 dba, exceeding the customer requirement, while simultaneously delivering an esthetically pleasing product.

Want to start your hydraulic system design today?  Contact our engineering team at 513-881-7000!

hydraulic power unit

hydraulic power unit

hydraulic power unit

hydraulic power unit

hydraulic power unit

hydraulic power unit

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