-17 Ch 4 Hydraulic Fluid Contamination

Question 1

Contaminants in hydraulic fluids are what types?

Answer 1

Organic, metallic solids, non-metallic (inorganic) solids, foreign fluids, air, and water

Question 2

How is Organic Contamination produced?

Answer 2

Organic solids or semi solids found are produced by wear, oxidation, or polymerization.
Minute particles of o-rings, seals, gaskets, and hoses, are present due to chemical reactions.

Question 3

Oxidative rate of hydraulic fluids increases with?

Answer 3

Increases with pressure, temperature, and the presence of system contaminants (wear particles, water, or dirt).

Question 4

How does oxidation products appear?

Answer 4

Appear as organic acids, asphaltics , gums, and varnishes if combined with hydraulic fluid form sludge.

Question 5

What contributes to most of metallic particulate contamination in a hydraulic system?

Answer 5

Hydraulic pumps because of continuous high speed internal movement. Metal particles are also produced by hydraulic valves, actuators, due to body wear and the chipping away of small pieces of metal plating materials.

Question 6

What does Inorganic Solid Contamination include?

Answer 6

Inorganic (nonmetallic)
Includes dust, paint particles, dirt, and silicates and Glass particles.

Question 7

Oil oxidation will result in what?

Answer 7

Oil oxidation products are not abrasive but will result in system degradation because the sludge or varnish-like materials that collect at close fitting moving parts, such as the spool and sleeve on servovalves, causing sluggish valve response.

Question 8

What are the effects of Particulate Contamination?

Answer 8

Contamination of hydraulic fluid with particulate matter is one of the principal causes of wear in hydraulic pumps, actuators, valves, and servovalves.

Question 9

What is fluid contamination?

Answer 9

Water, solvent, and other foreign fluid contaminations

Question 10

Free water contamination is?

Answer 10

Is a serious contaminant of hydraulic systems. Water can result in formation of ice, or oxidation products, condensed from air entering vented system.

Question 11

What is the effect of free water contamination?

Answer 11

Presence of free water can result in formation of undesired oxidation products and corrosion of metallic surfaces. Microorganisms may grow.

Question 12

Foreign Fluids contamination include?

Answer 12

Is rare , but result in lube oil, engine fuel, or incorrect hydraulic fluid having been introduced to system during servicing

Question 13

If foreign fluid is suspected, how do you verify?

Answer 13

Can be verified by chemical analysis of a fluid sample. Assistance of the Fleet Support Team (FST), (AFPET) or (ASG) must be requested to verify and identify the contaminant and to direct the required decontamination.

Question 14

What are the effects of Foreign Fluid Contamination?

Answer 14

May be mild or severe depending upon contaminant, the amount and how long it has been present.

Question 15

What is Air Contamination?

Answer 15

Dissolved, entrained, or free air.

Question 16

How do you minimize air being introduced?

Answer 16

By prefilling replacement components with new filtered fluid prior to installation.

Question 17

What are the effects of air contamination?

Answer 17

High air content can result in cavitation can cause severe mechanical damage within the pump, and partial or complete loss of output pressure. Air elsewhere creates slow or erratic actuator movement. Sometimes accompanied by vibrations

Question 18

How is size of particulate matter in hydraulic fluid measured?

Answer 18

In microns, millionths of a meter. A micron is equivalent to 0.0000394 inch and 25,400 microns equals 1 inch.

Question 19

If activities do not have access to a particle counter in their area or through a supporting I-level unit or NOAP Lab, how shall hydraulic fluid contamination be measured?

Answer 19

Patch Testing with the contamination analysis kit 57L414 (08071)

Question 20

The class of contamination is based in size range per ______ of hydraulic fluid.

Answer 20

100 ml

Question 21

What is the maximum acceptable contamination level for hydraulic systems in Naval aircraft?

Answer 21

Class 5

Question 22

What class must be for fluid delivered by SE to equipment under test or being serviced?

Answer 22

Class 3 or cleaner