21 - Eat 6

Question 1

A _________ strainer is called a filter. A) Fine B) Coarse C) Media D) Absorbent

Answer 1

B) Coarse pg 138 Notes: Usually constructed of fine mesh wire, with pores larger than 50 microns.

Question 2

A particle one micron in size equals _______ inch. A) .000583 B) .7053 C) .00275 D) .00039

Answer 2

D) .000039 pg 112 Notes: 39 millionths of an inch

Question 3

A filter designed to signal the operator when the element needs cleaning is called a(n) ________ filter. A) Circulating B) Off-line C) Absorbent D) Indicating

Answer 3

“D) Indicating pg 144 Notes:
They provide electrical or visual indication when element is near end of life.”

Question 4

Three general areas for locating a filter are inlet, pressure and ______ lines. A) Pilot B) Return C) Flow D) Relief

Answer 4

B) Return pg 134 & 135

Question 5

What type of filter element provides precise control of pore size? A) Cylindrical B) Sub-plate C) Surface D)Pleated

Answer 5

C) Surface pg 142

Question 6

Filtering materials are classified as absorbent or? A) Mesh B) Absorbent C) Fiber D) Depth-type

Answer 6

B) Adsorbent pg 142

Question 7

What type of filter passes the entire flow entering its inlet through the element? A) Proportional Flow B) Indicator Type C) Full Flow D) Reverse Flow

Answer 7

C) Full flow

Question 8

The smallest particle an eye can see is approximately ______ microns. A) 25 B) 40 C) 50 D) 75

Answer 8

B) 40 pg 112

Question 9

Hydraulic circuit components fail as a result of contamination and ______. A) Design B) Phase C) Static D) ISO

Answer 9

A) Design pg 113

Question 10

If the fluid within the hydraulic pump clearances becomes heavily contaminated, __________ will probably occur. A) Cavitation B) Fatigue C) Aeration D) Seizure

Answer 10

D) Seizure

Question 11

Which of the following is not a mechanism of wear? A) Adhesion B) Filtration C) Fatigue D) Cavitation

Answer 11

B) Filtration

Question 12

Contamination blockage which prevents and then allows a solenoid spool to shift is called a _______ failure. A) Degradation B) Catastrophic C) Transient D) Critical

Answer 12

C) Transient Also called “Intermittent or Transitory”

Question 13

In increase in the pressure differential across a filter will cause a(n) _______ in power consumption. A) Increase B) Half-wave C) Decrease D) Beta ratio

Answer 13

A) Increase Notes:
To minimize energy consumption, the average pressure drop across filters should be as low as possible.
(Pg. 141, Pressure Drop)

Question 14

When specifying the correct filter for a given application, which of the following would not be considered? A) Weight of particles to be held B) Flow rate capacity C) Flow sampling method D) Pressure drop through element

Answer 14

C) Flow sampling method

Question 15

Which is not a source of contamination in a hydraulic system? A) Ingressed B) Entrained C) Internally D) Built-in

Answer 15

B) Entrained

Question 16

The preferred location for dynamic sampling is directly _________ of the return line filter. A) Downstream B) Midstream C) Center D) Upstream

Answer 16

D) Upstream pg 119

Question 17

After hydraulic system assembly, tubing must not be soldered, welded or _____. A) Flared B) Threaded C) Brazed D) Plugged

Answer 17

C) Brazed pg 131

Question 18

When transferring clean oil, the transfer pump should be equipped with a _______ filter. A) Beta B) Coarse C) 5 micron D) Mesh

Answer 18

C) 5 micron pg 133

Question 19

Filters that can trap much smaller particles than inlet line strainers are _________ filters. A) Pressure line B) Return Line C) Off line D) Pilot line

Answer 19

A) Pressure line pg 134

Question 20

The higher the sieve or mash number the ________ the screen. A) Thicker B) Finer C) Thinner D) Coarse

Answer 20

B) Finer pg 138

Question 21

To test for filter material compatibility, the filter element is immersed for _____ hours in system fluid. A) 59 B) 63 C) 84 D) 72

Answer 21

D) 72 pg 141

Question 22

In cylindrical shaped filter elements, ______ tubes are used to support the media against pressure differential. A) Stainless B) Flared C) Perforated D) Bypass

Answer 22

C) Perforated pg 142

Question 23

Hydraulic fiberglass filter elements tend to have a ________ filtering structure. A) Stainless B) Mesh C) Surface D) Pleated

Answer 23

D) Pleated pg 142

Question 24

To eliminate the possibility of the filter element collapse, a _______ valve is used. A) Bypass B) Inlet C) Rotary D) Check

Answer 24

A) Bypass pg 144

Question 25

To monitor initial and sub sequential levels of contamination ________ points must be provided. A) Filter B) Sampling C) Static D) Dynamic

Answer 25

B) Sampling