Fluid Conditioning

Question 0

What is ISO 4406?

Answer 0

ISO Cleanliness standard that measures particles in oil

Question 1

What are four sources of ingressed contamination?

Answer 1

breathers, pistons, shafts, new lubricant, bad seals, failed filters, open or poorly sealed inspection hatches.

Question 2

What does ISO 16/14 mean?

Answer 2

an indication of the number of particles greater than 5 microns/15 microns.
Note: There are proposals to add a 2 micron standard, as well as to change the standard to 4 microns/6 microns/14 microns.

Question 3

What is a beta ratio?

Answer 3

Beta ratio is the ratio of particles greater than a given size going into a filter to the number coming out.

Question 4

What does β 3 200 mean?

Answer 4

It is the rating given a filter whose absolute rating is 3 microns and that for every 200 particles greater than 3 microns in size entering the filter, only one will exit.

Question 5

What is a graded pore filter?

Answer 5

A graded pore filter is one whose pores become smaller near the fluid exit.

Question 6

What is more effective, a fixed pore or a non-fixed pore filter?

Answer 6

A fixed pore filter is more effective because fibers are bonded. Non-fixed pore filters are more subject to breakage.
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Question 7

The three forms of water in lube oil are _______, _______, and _______.

Answer 7

free water
emulsified water
dissolved water
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Question 8

Name at least three negative effects the presence of water will have on the properties of a lubricant.

Answer 8

1. It causes rust and corrosion
2. Hydrogen embrittlement and water etching/erosion
3. It promotes oxidation
4. Depletes additives and reduces
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Question 9

How does emulsification of water affect a lubricant’s viscosity?

Answer 9

It increases until the proportion of water is very high, then it decreases.

Question 10

What is the smallest dot that most people (under age 40) can see with the naked eye?

Answer 10

40 microns (particles of 5 microns can cause damage in lubricating oil systems)

Question 11

Other than continuous filtering, what are other options that can be used to clean up systems that tend to get contaminated?

Answer 11

First, control the source of contamination.
Then try settling out water and contaminants, raising the system temperature to drive off water and facilitate settling, adding portable filters, centrifuging or vacuum dehydrating.

Question 12

Name three types of filter ratings?

Answer 12

Nominal Rating: An arbitrary micrometer value indicated by the filter manufacturer. Due to the lack of reproducibility rating is depreciated.

Absolute Rating: The diameter of the largest hard spherical particle that will pass through filter under test condition.

Filtration Ratio: The ratio of particles greater than a given size upstream divided by the number of particles of the same size downstream.

Question 13

Give recommended beta ratios for ball bearings, roller bearings and industrial gear boxes.

Answer 13

Ball Bearings ß (1 to 6) = 200
Roller Element Bearings ß (1 to 3) = 200
Gears ß (3 to 12) = 200
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Question 14

What are two primary objectives to consider when selecting a filter?

Answer 14

Cleanliness level
Flow rate
Dirt capacity
Operating perssure

Question 15

What are the two most important numbers that indicate the capacity of a filter?

Answer 15

Apparent dirt capacity

Retained dirt capacity

Question 16

What are the three major categories of component failure?

Answer 16

Catastropic
Intermittent
Degradation

Question 17

Clearance sized particles have what three effects on valves?

Answer 17

Surface erosion
solenoid burn-out
spool jamming
slow response/instability their effectiveness

It increases oil viscosity and plugs filters. It decreases bearing life and oxidizes babbitt. It freezes and promotes bacterial growth. Minerals may produce hard deposits. It may cause foam, although some studies dispute this.

Question 18

What is the typical clearance in a servo valve?

Answer 18

1 to 4 microns

Question 19

Piping selection is based on ________, which is measured in FPS.

Answer 19

Flow velocity

Question 20

Piping must be large enough to prevent _________ in the pump suction lines.

Answer 20

Cavitation

Question 21

What are the three steps of Systemic Contamination Control?

Answer 21

Set a target cleanliness level
Select filters & filter placement to achieve target
Sample fluid & confirm achievement

Question 22

Name four sources of contamination?

Answer 22

Contaminated new oil
Built in contamination
Ingressed (Introduced from outside)
Internally generated contamination

Question 23

Name four sources of contamination from outside sources?

Answer 23

Reservoir vent ports
Power unit access plates
Maintenance events
Cylinder rod seals

Question 24

Name three types of Generated Contamination?

Answer 24

Wear metals
condensation
foam

Question 25

Explain the “chain reaction” caused by abrasive wear?

Answer 25

Abrasive particles become work hardened (harder than parent surface)
Work hardened particles produce greater wear and move particles
New particles become work hardened
Chain reaction accelerates wear unless particles are removed by filtration.

Question 26

Name three types of adsorbent filters.

Answer 26

Fullers earth
actuated carbon
actuated alumina
zeolite.

Question 27

A servo system should have a filtration range of __________.

Answer 27

16/14/11

Question 28

Name four types of filter material.

Answer 28

Cellulose (paper)
fiberglass
synthetic fibers
wire mesh

Question 29

Name the three most common industrial contaminants in lubrication oil systems.

Answer 29

Water
solid particles
oxidation products

Question 30

What is the difference between full flow and by-pass filtration?

Answer 30

Full flow filtration allows all of the oil to flow through the filter. By-pass filtration draws off part of the oil from the main stream and crculates it through the filter.

Question 31

How does flow rates affect pressure drop across a filter?

Answer 31

As flow rate increases, pressure drop increases.

Question 32

Name examples of hard and soft particles that can contaminate lubricants.

Answer 32

Hard particles – silica, metals, carbon.

Soft particles – rubber, micro-organisms, fibers.