TECHNICAL REFERENCE
Hydraulic Components Need Protection
Types of Contaminant • Many different types of contamination may be present in hydraulic fluid, causing various problems. Some are: • Particulate (dust, dirt, sand, rust, fibers, elastomers, paint chips) • Wear metals, silicon, and excessive additives (aluminum, chromium copper, iron, lead, tin, silicon, sodium, zinc, barium, phosphorous) • Water • Sealants (Teflon®* tape, pastes) • Sludge, oxidation, and other corrosion products • Acids and other chemicals • Biological, microbes (in high water based fluids)
Fluid power circuits are designed in all shapes and sizes, both simple and complex in design, and they all need protection from damaging contamination. Abrasive particles enter the system and, if unfiltered, damage sensitive components like pumps, valves and motors. It is the job of the hydraulic filter to remove these particles from the oil flow to help prevent premature component wear and system failure. As the sophistication of hydraulic systems increases, the need for reliable filtration protection becomes ever more critical.
* Te fl on is a registered trademark of E.I.Dupont de Nemours & Co., Inc.
How Contamination Damages Precision Parts
Typical Factors in Component Life Studies show that most (typically 70%) of hydraulic component replacement 70% Surface Degradation
V al v e Bod y
This illustration of a simple hydraulic valve illustrates how particles damage components. In normal operation,
Inlet
S p ool
is necessary because of surface degradation, and most of that is due to mechanical wear. Proper filtration of hydraulic fluids can lengthen component life.
70% mechanical wear from: • abrasion • fatigue • adhesion
O utlet
O utlet
the spool slides back and forth in the valve body, diverting oil to one side of the valve or the other. If a particle lodges between the spool and valve body, it will erode small wear particles from the metal surfaces. As these wear particles are moved back and forth by the action of the spool, they can roll into a burr that jams the spool and disables the valve.
30% corrosion
15% Accidents
15% Obsolescence
Disaster Strikes When filters are not a main component of the hydraulic circuit, disaster awaits. Here, piston rings were eaten away by contaminants.
Component Damage Looking down the barrel of an hydraulic cylinder, we can see the scratches along the inside surface. Don’t cut costs by eliminating hydraulic filters. It could cost you more in the long run in major component repairs.
16 • Hydraulic Filters & Accessories
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