The Knoll 3-in-1 filter unit is a mobile unit that combines bypass filtration, oil changes, and filtered filling in a single compact device – fundamentally simplifying hydraulic maintenance. Anyone who maintains hydraulic systems knows the effort involved: pumping out old oil, ensuring bypass filtration during operation, and cleanly filling with fresh oil. Until now, a separate oil service unit was required for each task. This costs time, space, and money.
Knoll Hydraulik GmbH & Co. KG is changing that with a single, compact unit that handles all three hydraulic maintenance tasks.
The 3-in-1 hydraulic power unit is available now – exclusively through FILCOM GmbH and directly from the manufacturer, Knoll Hydraulik GmbH & Co. KG.
3-in-1 Unit vs. Three Separate Units: A Direct Comparison
Maintenance teams that currently use separate oil service units for pumping, bypass filtration, and filling benefit from significantly reduced equipment, cost, and logistics requirements with the 3-in-1 unit.
Feature 3-in-1-unit 3 individual units
Number of units 1 unit 3 units
Space requirement compact, mobile high
Setup time ready for immediate use Conversion required
Acquisition costs one-time investment triple investment
Maintenance costs minimal occurs 3 times
Operational flexibility high for all tasks limited
Oil purity ISO 4406 consistently ensured task-independent
The mobile filtration unit in practical testing: three key functions for hydraulic maintenance
- Pumping out hydraulic oil – quickly, cleanly, and without interruption: Speed is crucial when changing oil in hydraulic systems. The 3-in-1 unit reliably pumps out used hydraulic oil – without the need for a filter. A sophisticated ball valve system allows the filter to be bypassed when needed, preventing filter damage even in cases of heavy contamination and ensuring uninterrupted pumping.
Practical benefit: Reduced downtime for hydraulic maintenance, no filter wear during pumping.
- Bypass filtration – continuous oil cleaning during operation: Particles in hydraulic oil are a major cause of component failure. The mobile filter unit cleans continuously in a bypass flow – even while the system is running. High-quality Hengst filter elements with filtration levels of 3, 6, and 10 µm, along with a water separator, reliably remove solid particles and moisture, ensuring consistently high oil cleanliness according to ISO 4406. The flow rate can be continuously adjusted via a potentiometer on the electric motor – tailored to the specific system and operating conditions. No general increase or decrease, but precisely what the hydraulic system requires.
Practical benefit: Extended service life of pumps, valves, and seals through consistent maintenance of the cleanliness class. Costly breakdowns are avoided before they even occur.
- Filter fresh oil before filling – clean from the start: Fresh oil can be significantly dirtier than modern hydraulic components can tolerate. While new hydraulic oil typically has a cleanliness level around ISO 4406 19/17/14, sensitive servo and high-pressure hydraulic systems often require 16/14/11, for example. Depending on particle size, the contamination level can be many times higher. (Source: CJC Clean Oil Guide)
- The oil service unit provides the solution here: Hengst hydraulic filter elements with a rating of 3–10 µm clean the fresh oil before it is even filled. An optional water separator additionally removes moisture—ensuring targeted pre-filtration and clean hydraulic oil right from the start.
Practical benefit: Start-up damage is avoided, and the required cleanliness class is maintained from the very beginning – directly during the filling of the hydraulic system.
Quiet screw pump and particle counter: What makes this oil service unit technically stand out
The unit is designed for industrial use in hydraulic maintenance. All key technical features at a glance:
- Quiet screw pump: Extremely quiet and low-maintenance – a decisive advantage over conventional filter units in noise-sensitive production areas.
- Hengst filter elements (3–10 µm): High-quality filter elements with oil drain function and alternative water separator for reliable hydraulic oil filtration. Easily accessible and quick to replace.
- Infinitely variable flow rate control: continuously adjustable flow rate from 6 to 36 l/min via potentiometer – optimally matched to the requirements of the specific hydraulic system.
- Mobile design: Ergonomic solid rubber casters with two swivel casters and brakes – the mobile filter unit easily reaches even confined production areas.
- Protected control panel: Emergency stop button, main switch, and optional particle counter – shielded against dust, oil, and moisture.
- Noise level: Compared to standard units on the market, the Knoll 3-in-1 hydraulic power unit stands out due to its exceptionally low noise emission, with a maximum level of 70 dB.
- Optional MP-Filtri particle counter: Real-time monitoring of oil cleanliness class according to ISO 4406, AS 4059E, and NAS 1638 – including percentage water content display for comprehensive condition monitoring.
Two technical highlights are particularly noteworthy: The quiet screw pump is extremely low-noise and requires minimal maintenance – a decisive advantage over conventional filter units in noise-sensitive production areas. The optional MP-Filtri particle counter enables real-time monitoring of the oil cleanliness class according to ISO 4406, AS 4059E, and NAS 1638 – including a percentage water content display for comprehensive condition monitoring.
Applications: Where the mobile filter unit proves its worth
The 3-in-1 hydraulic power unit is designed for maximum mobility – ideal for maintenance teams that service various machines and systems with a single oil service unit:
- Industrial maintenance departments with regular oil change intervals for hydraulic systems
- Service calls directly at machines – hydraulic maintenance without disassembly
- Continuous bypass filtration during ongoing machine operation
- Filling and pre-cleaning fresh oil during the initial commissioning of new hydraulic systems
- Workshop and service operations with changing locations and systems
Product flyer for the Knoll 3-in-1 hydraulic power unit: all technical details in a nutshell
For a quick overview of all technical details regarding bypass filtration, hydraulic oil filtration, and the mobile filter cart setup, the official product flyer is available for download. Ideal for internal distribution within maintenance, for procurement inquiries, or for direct equipment comparison.
Flyer-A5_4-Seiter_de.pdf
HerunterladenFlyer-A5_4-Seiter_en.pdf
HerunterladenLearn more: The new product page is live!
All further information, technical specifications, FAQs and contact options for the Knoll 3-in-1 hydraulic power unit are now available on the new product page!
Frequently Asked Questions about the Knoll 3-in-1 Filter Unit
Which hydraulic oils is the unit suitable for? The unit is suitable for common mineral oil-based hydraulic oils. The Hengst filter elements are designed for typical industrial use with HLP oils. For special fluid types (e.g., HEES, HFD), we recommend consulting FILCOM or Knoll Hydraulik before purchasing.
What oil cleanliness class according to ISO 4406 is achieved? With the Hengst filter elements in 3 µm filtration, high oil cleanliness classes in the range of ISO 4406 Class 15/13/10 and better can be achieved – depending on the initial condition of the oil, flow rate, and operating time of the bypass filtration system.
What does ISO 4406: 15/13/10 mean?
The three numbers indicate the number of particles in the hydraulic oil across three defined particle size classes. The count represents the number of particles per 100 ml of oil.
| ISO code | Particle size | Number of particles / 100 ml |
|---|---|---|
| 15 | ≥ 4 µm(c) | 16.000 – 32.000 |
| 13 | ≥ 6 µm(c) | 4.000 – 8.000 |
| 10 | ≥ 14 µm(c) | 500 – 1.000 |
In summary: ISO 4406: 15/13/10 describes the contamination level of a hydraulic oil based on the number of particles present. The lower the three numbers, the cleaner the oil. For a rating of 15/13/10, for example, there are between 16,000 and 32,000 particles ≥ 4 µm and between 500 and 1,000 particles ≥ 14 µm per 100 ml of oil.
Can the unit be used as a continuous bypass filtration solution? Yes. The stepless flow rate control and the robust, mobile design make the 3-in-1 unit suitable for continuous bypass operation. It is not limited to occasional service calls.
How is the unit connected to the hydraulic system? Connection is made via flat-face couplings – these ensure a completely leak-proof connection. The system is designed for quick and clean connection without oil loss during any service call.
When and where will the Knoll 3-in-1 filter unit be available? The unit will be available from July 2026 – exclusively through FILCOM GmbH (authorized distributor) and directly from the manufacturer, Knoll Hydraulik GmbH & Co. KG.
Is there a product flyer available for download? Yes. For a quick overview of all technical details, the official product flyer is available for download – ideal for internal distribution within maintenance, for procurement inquiries, or for direct device comparison.
Availability & Purchasing
The Knoll 3-in-1 hydraulic power unit will be available from July 2026 – exclusively through:
- FILCOM GmbH: authorized distributor – with comprehensive consultation
- Knoll Hydraulik GmbH & Co. KG: directly from the manufacturer – for technical questions and individual inquiries
Interested?
Hydraulic systems are the heart of many plants. With the right oil service unit, you protect not only the hydraulic oil but your entire investment. The Knoll 3-in-1 power unit combines bypass filtration, oil changes, and filtered filling in a compact, mobile unit, providing a sophisticated solution to the demands of modern hydraulic maintenance.
Do you have questions about the Knoll 3-in-1 hydraulic power unit?
Carmen Steiner specializes in the design and optimization of filter solutions for hydraulic systems and machine tools. With her many years of practical experience, she helps companies increase plant efficiency, reduce wear, and sustainably improve plant availability.
