Sharp, dense particles passing right through filters can rob performance and steal life from hydraulic filters.
All hydraulic fluid, lubricating oil, and coolant in Caterpillar heavy equipment pass through barrier-type filters designed to remove solid contamination. These filters are excellent at removing contaminants larger than the smallest pores in the filter. However, these fluids also contain very small, shards of ferrous metal so small that they can pass through filter media and attack pumps, valves, cylinders, and other critical components used in Caterpillar's heavy equipment.
Whayne Supply Co., Louisville, Ky., is the largest Caterpillar dealer in North America. Edwin Downer, general manager of Whayne’s Technology Div., and his colleagues were looking for ways to remove these troublesome contaminants. After meeting with representatives from Magnom at ConExpo, Whayne officials considered Magnom’s Core Technology as a potential solution to ongoing premature system wear and costs associated with frequent maintenance and repairs caused by contaminated fluids.
Downer said the first step was to validate Magnom’s technology to determine its effectiveness. (See the end of this article for a description of the technology.) The turbocharger drain line on a Caterpillar 3406 E was selected for this initial testing. A Magnom Midi inline unit was installed downstream of the system’s normal barrier filter, which was rated to remove all solid contaminants larger than 5 μm.
After two months of normal operation, the Midi unit was removed and its core examined. The core had collected a significant amount of small metal particles down to sub-micron size that had passed through the system’s barrier filter. This test validated two important points for Downer. First, the existing filter system, while providing excellent filtration of contaminants larger than 5 μm, was allowing a significant amount of smaller particles to pass through. Second, the Magnom Core was efficiently removing these small metal particles.
The results also showed the need for additional testing to determine if removing these small particles would improve system life and reduce maintenance costs. If so, could a custom housing be designed to allow quick and easy installation on the Caterpillar equipment?
Whayne officials next chose to test the hydraulic fan drive system on Cat D11 R tractors. These machines operate 20 hr/day, 7 days a week, with an average life of about 4000 hr for the fan drives. Two systems were selected for the test, and Magnom inline units were installed on high-pressure and return lines connecting the hydraulic power unit to the fan drive. After 15,000 hr in service, the fan drive system on the first D11 finally required service. Installing the Magnom units extended the service life to almost four times the average, saving the costs otherwise associated with three fan drive failure repairs.
Typical service costs associated with a fan drive failure were estimated at $22,000 per event, so the total savings was calculated at $66,000. Installation costs for the Magnom units totaled less than $1,000, and at the time of this writing, the fan drive in the second D11 was still operating. Downer said he believes the testing revealed the benefits derived from adding Magnom units to conventional filter systems. “The combination of a traditional barrier filter and the Magnom Core technology provides an enhanced filter system with high efficiency, lower system operating costs, and higher equipment performance.”
Taking it a step further
Whayne and Magnom officials also began a program to design a product that would allow technicians to quickly install Magnom units on existing equipment. Objectives were that the units would:
- be easy to install and service in the field,
- not require significant modification to existing systems,
- withstand the demands of the severe working conditions normally experienced by Cat equipment, and
- exhibit low cost.
Magnom had already developed a housing for installing the magnetic cores between an engine and spin-on filter, so this concept was repeated to meet the design criteria identified by Whayne. The sandwich configuration was modified to eventually become the Whayne Pre- Filter Unit (PFU).
Whayne and Magnom later modified the design to include safety and easeof- use features, such as eliminating any risk of incorrectly installing the PFU and adding structural strength to the design and increasing mounting and attachment options. Whayne installed units on a fleet of Cat 330 rental units that had been fitted with hydraulic hammers — among the most punishing applications in all of mobile hydraulics. Installing the inline units on the high and low pressure lines connecting the hammer to the host unit reaps two benefits. First, the Magnom units protect the main hydraulic system of the Cat 330 by removing any contamination generated in the hammer. Second, the Magnom units prevent cross contamination. Tools and host machines used by Whayne customers are paired in any number of combinations. If any of the component contains high contamination, adding Magnom units to the system prevents an “infected” component from passing the contamination on to the host machine’s hydraulic system.
Whayne formed a Technology Division to market these innovative products to reduce customers’ equipment operating costs. Whayne also provides the products to their extensive fleet of rental equipment, their in-house fleet of service and transport trucks, and other Caterpillar dealers.
This article appeared in print as "To Catch a Thief" in the September 2011 issue.