Skip navigation

Filters ensure hydraulic fluid is clean from the get-go

Amsoil employee installs new element into Donaldson HRK10 filter housing. The filter’s twist-and-lift feature simplifies element changeout because retaining bolts need not be removed, only loosened.

Filtration continues to be a hot topic in the hydraulics industry. The benefits of keeping fluid clean include higher system reliability, longer component life, improved efficiency, and more responsive system operation. In a nutshell, the money invested in keeping fluid clean pays for itself many times over in more economical operation of the hydraulic system.

However, one often overlooked source of contamination is when new fluid is added to a system. Unfortunately, the best-laid plans for keeping hydraulic oil clean through filtration can be defeated when fresh fluid added to a system is not as clean as the fluid already in the system.

Growth leads to expansion
Amsoil Inc., a manufacturer of synthetic lubricants, recently expanded its production area, storage capacity, warehouse, and offices in Superior, Wis. to increase production rates while maintaining its high standards of fluid cleanliness. Scott Davis, Amsoil VP of operations, and Rob Hendrickson, facilities and engineering superintendent, oversaw the expansion from start to finish. The Amsoil team relied on Ralph Beamer of Globetech Services, Inc., Glen Ellyn, Ill., a fullservice control systems integrator, for assistance in the mechanical process design of the new production facility.

Amsoil and Globetech turned to Donaldson Co. Inc., Minneapolis, to provide online filtration of Amsoil lubricants. Donaldson recently introduced an expanded line of industrial filter housings — including its HRK10 in-line hydraulic filter — that can be customized to meet specific application requirements. With static burst ratings to 500 psi and flow capacities to 300 gpm, the new housing and element deliver higher efficiency filtration with high dirt-holding capacity and low pressure drop.

Donaldson recommended Amsoil install 30 HRK10 in-line filter housings to maintain production times and the fine micron standards Amsoil demands. These filter housings are constructed of steel and incorporate a basket-like design to ensure that contaminants captured by the filter remain in the filter, especially when elements are changed. The lubricant flows from inside the filter to the outside, keeping contaminants trapped inside and allowing the filter to be easily removed with the contaminants still intact.

“Amsoil has always filtered its products to a higher degree than industry standards mandate, and the recent transfer of our production facilities provided the perfect opportunity to investigate new filtration technologies,” said Davis. “The Donaldson HRK10 filters are more than capable of withstanding the high flow rate and high pressures found in our production lines. They also help us meet our stringent quality standards while simultaneously improving efficiency and production.”

Housing benefits
The HRK10 housings were modified to better fit within the Amsoil’s piping scheme, allowing better drainage and cleanliness than is possible with conventional housings. Commenting on the customization, Ralph Beamer of Globetech offered, “We utilized the HRK10 design because it allows relocating the outlet port without significant delay in building the housings. Additionally, Amsoil will boost productivity by reducing changeover time.”

The HRK10 housing also offers improvements in bypass valves, cartridge sealing, cover closure, and filter media performance. A new cover closure design, referred to as Donaldson’s Twist and Lift, requires that closure bolts only be loosened, but not removed, for access to the filter element.

It’s elementary
Amsoil uses elements featuring Donaldson’s Synteq filter media, which offers performance advantages over cellulose and other synthetic media. Davis explained that Amsoil requires filtration specifications to exceed industry standards, and are met with the Synteq media. “These filters last 1.6 times longer than our old filters, which offset the price difference and ensures the cost-effectiveness of filtering our synthetic lubricants to the highest quality,” said Davis.

For more information about Donaldson products for industrial hydraulic applications, visit For more about Amsoil hydraulic fluids and lubricants, visit