The performance of the hydraulic system depends on the quality of the hydraulic fluid.
For this reason the most important component on a hydraulic reservoir is the filter as it ensures the stored fluid remains clean and free of contamination.
The most used filtration solution for this specific function is the tank-top filter, which performs an important function as it cleans the fluid before it flows back to the hydraulic reservoir.
Tank-top filter layout and function
The tank mounted return line filter is located in the return line for direct attachment onto the tank of a hydraulic or lubrication system.
Optionally, the filter can also be installed as an inline filter in a pipeline.
The tank-top filter layout basically consists of filter head and cover (1), filter housing (2), filter element (3a), as well as a serial bypass valve (3b). The filter can be also equipped with maintenance indicator (4), both electrical and visual, and additional features and accessories, as filling plugs, air breather (5), dipstick (6).
During operation, the hydraulic fluid reaches the filter housing via the inlet; here, it flows through the filter element (3) from the outside to the inside and is cleaned according to the filter rating. The dirt particles filtered out settle in the filter element. Via the outlet, the filtered hydraulic fluid enters the tank. When the element becomes fully contaminated, the required element change is signaled by the maintenance indicator (4).
Tank-top filters sizing
Return-line filters can be sensitive to flow surges, that can be caused by multiple valves shifting simultaneously or from flow intensification from cylinders.
This means it is important to size return-line filters for maximum flow of the hydraulic system (max l/min).
To correctly size the best filter for a specific hydraulic system, you can use one of the sizing applications available on the website of the main return-line filters manufacturers, such as the CAF Computer Aided Filter configurator of UFI Hydraulics.
Tank-top filters main benefits
Return line tank-mounted filtration offers a space saving solution for OEM’s of mobile machinery seeking to reduce the volume dedicated to hydraulic components, especially in the construction equipment and in the agricultural industry (tractors, ploughs, sprayers, harvesters, dryers, etc.), that use return line filter for smooth operations.
Tank-mounted filters are one of the most flexible and robust solution in the hydraulic world, as usually offer a wide range of configuration options and available features.
Return line filters usually have low-pressure housings, which are less expensive than their high-pressure counterparts, so that they can be considered as extremely versatile.
Tank-top filters maintenance and spare parts
Although return filters are widely used, few standards exist to regulate consistency from one manufacturer to another. This means that replacement filter elements from sources other than the original may not be completely interchangeable and that the selection of a reliable and experienced supplier is highly recommended.
UFI Filters Hydraulics has an extensive experience in designing filter products that can fit every application associated with the reservoir set up.
Moreover, besides the wide range of return line filters, that can cater to most porting configuration and indicator orientation that is commonly used in the hydraulic world, UFI Filters can develop and manufacture custom options depending on a customer’s specific need and layout.
Contact our sales team for further details on tank-top return filters and for any additional customised request.