Air-Over-Oil Hydraulic Power Unit Retrofit

Thursday, April 23, 2020
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Air-Over-Oil Retrofit

The Challenge

Micronics routinely goes on-site and performs a complete inspection on filter presses across a wide range of customer industries and geographies. Inspections and routine press maintenance are critical to maximizing your press’ performance! We perform inspections on Micronics presses as well as other OEMs’ filter presses.

While on a recent service call to a steel fabrication company, the customer reported that their 800mm filter press’s current Air Over Oil Hydraulic Power Unit was not performing properly. It was unable to build sufficient clamping pressure and their intensifying pump was running continually.

Performance was so poor that they were actually needing to replace the pump every 90 days or 4x/year. Not only did they incur $6000 per year in replacement part costs but, leaking of the press resulted in poor cake quality. This drove longer cycle times, and greatly increased time needed to clean the press between cycles. Plus, the poorer quality cake increased the company’s disposal costs.

Micronics has considerable expertise in optimizing filter press parts performance to maximize press efficiency and up-time so we knew we could provide a robust, cost-effective solution.

The Solution

It isn’t always a complex solution. It is often deep expertise based on years of field experience that allows us to troubleshoot, both physically on-site and often over-the-phone. This is definitely worthy of consideration in these times of minimizing travel and following guidelines for social/physical distancing.

Via the telephone, Micronics personnel – working with onsite customer personnel – conducted several troubleshooting tests. Based on this troubleshooting & problem identification, we were able to determine that the seals in the customer’s hydraulic ram were allowing fluid to “bleed” by, and this was ultimately the cause for the lack of pressure and the continuation of the intensifying pump cycling.

Since this was an 800mm, 15 chamber filter press, we were able to evaluate that the return on investment associated with replacing the ram would in fact be greater than the return associated with rebuilding the existing older unit.

The customer elected to replace his existing Air-Over-Oil HPU with a Micronics unit. In fact, Micronics personnel designed a replacement HPU and assisted with the installation including installation of a new ram.


With the implementation of the Micronics-designed Air-over-Oil HPU, the customer could now achieve proper clamping pressure, thus allowing the intensifying pump to work as designed and not continually. With the Micronics Air-Over-Oil HPU Retrofit, proper cake formation could now take place and disposal costs could be decreased. The customer is very happy with Micronics’ Air-Over-Oil HPU Retrofit Solution.


You can count on Micronics to supply you with reliable and customized HPU solutions. Contact us and let us put our filtration solutions to work for your filtration challenges.

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