down arrow
| By Aberdeen Dynamics

Types of Hydraulic Filters

Regardless of your system’s existing filtration components, Aberdeen Dynamics’ has a filtration solution for any application and a proper filter selection is only a few questions away.  Recommended fluid cleanliness levels can vary depending on the types of components used within a fluid power system. With Aberdeen Dynamics’ support, your system can achieve optimal fluid cleanliness while minimizing downtime.

Environment, fluid type and system pressure all factor into the selection of filtration products.  Most fluid power systems use a combination of low-pressure filters combined with medium or high-pressure filters to adequately control fluid cleanliness levels. It is critical to understand component sensitivity within a fluid power system before selecting a proper filter.  Aberdeen Dynamics has the resources to assist in this process and understands that each application requires a thorough consultation.  

Filter element performance is rated upon several characteristics including micron, efficiency, dirt capacity and flow vs. pressure loss.  Properly sized, installed and maintained filtration plays a key role in machine preventative maintenance planning. The function of a hydraulic filter is to clean oil, but the ultimate purpose is to reduce operating costs.  The disposal cost of a drum of waste oil can be 4 to 5 times the cost of a drum of new oil. New fluid is not necessarily clean fluid. Typically, new fluid right out of the drum is not suitable for use in hydraulic or lubrication systems.

Before introducing new fluid into the system, it is best practice to utilize a type of off-line filtration system to obtain the recommended fluid cleanliness level suitable for operation.  Off-line filtration can be a solution for many applications such as transferring fluid from drum to tank, conditioning fluid that is already in use, removing free and emulsified water and can be complementary to existing system filtration. A common off-line filtration tool is the portable filter cart which features a heavy-duty frame equipped with a hydraulic pump, dual filters, flexible hose and wand assembly and optional particle counter to self-diagnose contamination levels.  The portable filter cart is a user-friendly and convenient option when servicing hydraulic systems.

Suction filters are located within the hydraulic reservoir and offer last chance protection for the hydraulic pump.  Designed for direct installation into suction lines of pumps, suction filters should always be installed below the minimum fluid level of the reservoir.  Suction filters are much easier to service than a sump strainer and can prevent costly damage to your hydraulic system. This filter type does not protect downstream components from pump wear debris and may not be suitable for some variable volume pumps.

Low-pressure filters are typically rated for up to 150psi and are located in system return lines, and can also be used as reservoir breathers. A common type of low-pressure filter is the spin-on disposable canister. The spin-on filter is often economical and easy to handle because oil is contained inside the canister.  When properly sized and installed, a spin-on filter element can last for up to 500 hours of operation. More frequent replacement may be required when operated in heavily contaminated areas such as foundries, grinding operations and mobile equipment.  Under these conditions, spin-on filter canisters should be replaced every 250 hours. A pressure indicator gauge located on the filter’s head will inform the user that differential pressure is exceeding the bypass setting and oil is no longer being filtered through the canister, therefore, signaling that a filter change is needed.  

For more efficient contamination control and performance, a tank top mounted return line filter such as Parker’s GLF series filter, provides added features and benefits.  Because this type of filter is mounted on top of the hydraulic tank, the filter element is less restricted in overall length and can provide excellent flow diffusing, controlling aeration.  The bowl-less design of the tank top return filter provides a service-friendly design that combines high particle capture efficiency with high dirt holding capacity while maintaining a low differential pressure drop.  The GLF series filter features inside-to-outside filtration where all captured contamination is retained inside the element which helps prevent recontamination of the system during the change of the element. The GLF series also features a unique head with two inlet ports to provide flexibility during installation and allow added oil to be filtered before entering the system.  The GLF series tank top filter consists of more than ten different configurations making this filter an ideal solution for most industrial or mobile applications.

Medium pressure filters have been developed to provide efficient filtration for applications requiring 500 to 1200 psi and are found in-line to protect hydraulic components downstream of the pump. With several medium pressure filter models to choose from, it is best to start by understanding the system’s max pressure and the required flow rate. Most medium pressure filters are rated to handle flow rates of 50 to 425 gallons per minute. Aberdeen Dynamics can assist in filter selection to help minimize costs, but also ensure specifications are equipped to meet your application demands.

For medium pressure applications that require an environmentally-friendly solution, Parker’s 12CS and 50CS hydraulic filter models feature a reusable bowl and a patented filter element with reinforced polymer end caps.  The element core is permanently attached as part of the filter bowl. When replaced, the 12CS/50CS coreless element reduces costs, eliminates hot drain requirements, can be easily incinerated and is better-suited for most landfills.  Some applications for the Parker 12CS/50CS include mobile agriculture, construction, material handlers, machine tools, joystick controls and industrial power units.

Lastly, high-pressure filters are used in applications where pressures exceed 1,200 psi.  The majority of applications that use high-pressure filters operate within a 1,200 psi to 7,000 psi pressure range. Similar to medium pressure filters, the high-pressure filters are located in-line within the hydraulic circuit and downstream of the hydraulic pump to provide protection for more sensitive hydraulic components. High-pressure filters offer a variety of options such as port sizes, filter element performance and high strength filter housing designs.

The Parker World Pressure Filter (WPF) has set out to become the industry standard in high-pressure hydraulic filtration. The durability, performance and variety of customizable options make the WPF series filter a viable solution for many of our industry’s most demanding applications. The WPF series filter contains a high strength ductile iron filter head with integral indicator port, steel bowl with standard drain cap and coreless element assembly that allows some elements to be re-usable.

Aberdeen Dynamics is committed to contributing towards our customer’s success and is ready to assist with all of your hydraulic filter needs.