KNOLL 3-in-1 Fill/Bypass Filter Unit

KNOLL 3-in-1 Filter Unit – Mobile Oil Maintenance Unit for Hydraulic Oil

The KNOLL 3-in-1 fill/bypass filter unit performs three hydraulic oil maintenance tasks with a single device: draining used hydraulic oil, bypass filtration during operation, and filtered filling and pre-cleaning of fresh oil. This model is supplied without particle monitoring; oil purity can be checked at any time via the Particle Monitoring Kit (Item 17-0002672) retrofit. FILCOM is an authorized distributor of KNOLL Hydraulik.

Filter the hydraulic oil instead of changing it prematurely

Bypass filtration cleans the hydraulic oil during operation and maintains a consistently stable purity class. This extends the service life of pumps, valves, and cylinders, reduces unplanned downtime, and increases the oil’s service life. During drainage, the ball valve system diverts the flow past the filter—thus preventing heavily contaminated used oil from loading the filter element. During filling, the fresh oil passes through Hengst hydraulic filters with particle sizes ranging from 3 µm to 10 µm—a water separator filter is available as an option in exchange for the other filters.

Quiet screw pump instead of a gear pump

The low-maintenance screw pump with strainer protection operates more quietly than standard gear pumps on the market and is therefore also suitable for noise-sensitive production areas. The flow rate can be continuously adjusted between 6 l/min and 36 l/min to suit the application—low for gentle bypass filtration, high for short filling and transfer times.

Technical Specifications

Flow rate 6–36 l/min, continuously adjustable via a potentiometer. Plugs into a standard 230-V outlet, allowing it to be used on different machines without the need for electrical installation. Filter material: glass fiber; filter area: 1,572.37 cm²; permissible differential pressure: 30 bar; seal materials: FKM (filter) and NBR (pump). To change the filter, a front flap opens; the oil is first drained via a shut-off valve; flat-face couplings ensure a drip-free connection, and solid rubber rollers allow the unit to roll smoothly across factory floors. Customization with a company logo is available for an additional charge.

Scope of Application

Typical applications: oil changes, tank drainage, and bypass filtration on machine tools, presses, and industrial hydraulic systems, as well as filtered initial filling of new equipment.

Order Filter Elements

Hengst filter elements are wear parts and are not included with the product. Please select the appropriate filter rating in the "Accessories" section on this page and order them along with your purchase. These same elements can later be used as replacements when changing the filter—keeping them in stock helps minimize downtime.