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Hydraulic filtration categories

Hydraulic filters, filter systems, filter components and electronics, among several others, have each been grouped to easily categorise the most appropriate filtration solution for your hydraulic application.

These categories include:

Hydraulic filtration brands

The Hytec Group guarantees that it uses only the best and world-renowned brands in all of its products and equipment. With this in mind, HFT uses only the following brands in its hydraulic filtration offering, and upholds all its OEMs’ warranties. These OEM brands are:

The importance of hydraulic filters

Filtration quality is the single most important measure of a hydraulic machine’s health. More hydraulic failures are a result of particle contamination than any other cause. Some inside information is required to effectively apply filtration, but it mostly boils down to size, location and quality.

Hydraulic filters are sized based on the flow passing through them at an acceptable pressure drop. It is important to consider pressure drop, which is the pressure developed by the friction of the fluid against and through the material of the filter assembly itself, because the majority of filters are installed with a bypass valve designed to open by the backpressure created by the clogged element. By sizing a filter intelligently, pressure drop is created only as the element becomes clogged with particles, preventing premature bypass, a condition when fluid passes through unfiltered.

To prevent excessive pressure drop, filter assemblies are often sized larger than required. An oversized assembly ensures little energy is lost to pressure drop, and as a corollary, larger filter elements are capable of holding more dirt before they become clogged. Because an adequately sized filter assembly provides both higher dirt-holding capacity and higher flow capacity, the choice to oversize a filter is limited only by real estate and price. With this in mind, choose filters as big as is reasonable. Never install a filter with borderline flow capacity, as it can go into bypass quickly and often, especially as it becomes clogged.

Additional considerations for sizing a filter are the fluid type and viscosity, as well as the quality and efficiency of the filter media. Highly viscous oil creates more backpressure than thin oil, and you should also consider how oil viscosity will vary with extreme changes in ambient temperature, such as with mobile equipment. Obviously, cold oil is thicker, and a marginally sized filter will bypass until the fluid reaches operating temperature.

Filter media quality plays a part in sizing assemblies for two reasons: Finer filtration (i.e., lower micron rating), is more restrictive to flow because of the smaller gaps in the media, which are required to trap smaller particles. Also, the quality of the filter media plays a part because premium synthetic depth-media has a higher dirt holding capacity and will take longer to clog than cheap paper or cellulose media. If you are unsure of the variables when you are applying or purchasing a new filter assembly, it is advised to oversize the element and to use a high-quality medium.

(*An extract from an article in Fluid Power World entitled Hydraulic filters: Size, location, and quality; penned by Paul Heney.)

The Hytec Group, a Bosch Rexroth company, brings the world’s leading hydraulics, pneumatics and automation brands to sub-Saharan Africa!