Power unit contamination example (Drop down 6)
Suggested exercises and observations
1. Select 'Contamination control', from the drop-down list menu 6.
♦ Operate the cylinder and observe how the contamination comes in from the pump, cylinder and air breather.
♦ Increase the flow from the offline cooler pump to observe how the offline filters remove the contamination.
Contamination risk review execise
Study a hydraulic system in your company or use the scissor lift design project example:
♦ Write down all of the sources of contamination. Consider all environmental, duty cycle, component selection, and housekeeping procedures, etc.
♦ Measure the current level of contamination in the fluid.
♦ Suggest ways the fluid cleanliness might be improved and potential reliability improvements.
Experiment 1: Consider the ways dirt enters the circuit or is generated by the components.
Question 1: Which of the following is NOT a source of contamination? Air breathers, cylinder rods, new fluid, worn pumps, maintenance, dry starts, lunch breaks, working outside normal operating conditions.
Experiment 2: Fluid contamination is measured by three-figure particle counters to ISO4406
Question 2: Which of the following readings is good and which is unacceptable? 24/20/15 - 15/13/11
Experiment 3: Dirt particles come in every size. Large particles tend to settle out but the small ones move around the circuit in the fluid.
Question 3: Can you see the particles that cause failures in hydraulic valves with only 6 micron spool clearances?