Main functions

1. What are the main functions of the 3-in-1 hydraulic power unit?

The unit combines three key functions for hydraulic maintenance:

• Pumping out used oil (unfiltered, to allow high flow rates without filter overload)
• Bypass filtration during system operation to keep the oil permanently clean
• Filtered filling and pre-cleaning of fresh oil to remove particles and water before filling.

This combination makes the unit a universal tool for maintenance, servicing, and service operations.

Bypass filtration

2. Why is bypass filtration so important?

Hydraulic systems are extremely sensitive to contamination. Even the smallest particles can:

• Damage control edges
• Wear out pumps
• Destroy seals
• Trigger system malfunctions

The flow rate can be continuously adjusted via an electric motor using a potentiometer. This allows for the continuous removal of contaminants and water, even during operation. This significantly increases system reliability and extends the service life of the entire hydraulic system.

Pre-cleaning of fresh oil

3. How does pre-cleaning of fresh oil work and why is it necessary?

Fresh oil is not automatically clean – even new hydraulic oil can be up to 20 times dirtier than most systems allow.

The unit filters according to ISO 4406 with high-quality Hengst filters (3–10 µm) and a water separator:

• Solid particles are reliably removed.
• Water, condensate, and moisture are reduced.
• The oil purity meets the requirements of modern hydraulic components.

This significantly reduces the risk of start-up damage.

Difference to standard equipment

4. How does the Knoll unit differ from standard equipment?

The Knoll 3-in-1 unit offers several technical advantages:

• Extremely low noise level thanks to the screw pump
• Higher and more flexible flow rate
• Robust, maintenance-friendly design
• Contamination indicator + optional particle counter
• Flat-face couplings for absolutely clean coupling
• Long-lasting Hengst filters with water separation

This combination is unique in this form and makes the unit particularly attractive for industrial applications, workshops, or service calls.

Oil cleanliness

5. What options are available for monitoring oil cleanliness?

Optionally, an MP-Filtri particle counter can be directly integrated. This

• measures cleanliness classes according to ISO 4406, AS 4059E, and NAS 1638
• enables trend analysis
• supports condition monitoring
• indicates whether action is required
• illumination indicator when the defined cleanliness class is reached

For operators, this means maximum transparency regarding the condition of the oil and the entire system.

Filter types

6. Which filter types are used and how often do they need to be changed?

• Fine filters (3–10 µm) for particle separation
• Water separator filters for reducing moisture

A change is necessary when:

• the contamination indicator is triggered
• an oil change is performed
• different types of oil are to be used (to prevent mixing)
• the unit has been stored for an extended period

The filters are easily accessible, making replacement particularly simple.

Oil types

7. Can different types of oil be used with the unit?

Yes – however, mixing different oils must be strictly avoided. If the same oil is not used as before, the following must be done:

• The unit must be completely drained
• The filter elements must be changed
• Residues must be drained

An oil mixture can lead to problems such as:

• cavitation tendency
• additive reactions
• foaming
• increased wear

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Areas of application

8. How mobile is the unit and for which areas of application is it suitable?

The unit is designed for full mobility:

• heavy-duty solid rubber wheels
• two swivel casters with brakes
• compact design

It is ideally suited for:

• maintenance departments
• service calls directly on machines
• oil changes in industrial plants
• bypass filtration during machine operation

Even confined spaces are easily accessible.

Safety Features

9. What safety features are integrated?

The power unit offers several protective functions:

• Emergency stop button for immediate shutdown
• Protected control panel against dust, oil, and moisture
• Contamination indicator
• Flat-face couplings prevent leaks
• Secure transport thanks to lockable casters 

These features ensure safe and clean operation.

Sales launch

10. When will the power unit be available and where can it be purchased?

The Knoll 3-in-1 hydraulic power unit will be available from spring 2026. Available exclusively through:

• FILCOM GmbH (authorized distributor)
  
• Knoll Hydraulik GmbH & Co. KG

Both suppliers offer comprehensive consulting, support, and service.