Hydraulic filters
Items are being added
KIT is adding items to this category. If you need a specific part, please send a quote request.
Frequently asked questions
What do a 10 micron rating and beta ratio mean?
The beta ratio under ISO 16889 is the count of particles larger than a given size upstream divided by the count downstream. Beta 10 equal to 200 means the element retains about 99.5 % of particles larger than 10 microns. Compare elements by beta ratio at the same particle size, not only by nominal micron figures.
How do suction, pressure and return filters differ?
Suction filters sit before the pump and are usually coarse strainers to avoid cavitation. Pressure filters sit after the pump in high pressure housings, protecting contamination-sensitive servo or proportional valves. Return filters sit on the line back to the tank, capturing contamination generated in the circuit, and are the main filter in many systems.
What must I match when using another brand's filter element?
Element dimensions (inside and outside diameter, length), seal type, filtration rating and collapse pressure. Media such as glass fibre or cellulose affects efficiency and dirt holding capacity. An element that fits but does not seal at the O-ring lets oil bypass the media.
When should a filter element be changed?
Change it when the differential pressure gauge or indicator shows the element is clogged, or at set intervals if there is no indicator. Once clogged, the bypass valve opens and dirty oil goes straight into the circuit. Indicators can give false alarms when oil is cold and thick, so read them at operating temperature.
How does a differential pressure indicator on a filter work?
The indicator senses the pressure difference across the element, which rises as the element holds more dirt. At a preset threshold, a visual indicator pops up or an electrical switch signals that the element needs changing. Cold, thick oil at startup can trigger it temporarily, so read it once the oil is at working temperature.
What does the bypass valve in a filter housing do?
The bypass valve opens when the element clogs so oil flows around it, preventing element collapse or pump starvation. While it is open, unfiltered oil enters the system, so a change indication must be acted on promptly. Filters guarding servo valves usually use a non-bypass design with a high collapse rating element.
How do I change an element without adding dirt to the system?
Stop the system, relieve pressure and clean the outside of the housing before opening it. Replace the cover O-ring, keep the new element away from dirty hands and the floor, and inspect the old element for unusual metal debris. Do not wash and reuse paper or glass fibre elements, because the media is damaged.
Is an offline (kidney loop) filter worthwhile?
An offline filter uses a separate small pump to circulate oil through a fine filter continuously, even when the main machine is idle. Because flow is steady and free of pressure surges, the element captures dirt more effectively and reaches higher cleanliness. It is especially useful on large reservoirs, or with water absorbing elements where water is present.
