INDUSTRIAL TECHNOLOGY FLUID POWER EXAM WITH VERIFIED
ANSWERS #11
1. Name five functions that the fluid in a hydraulic circuit must perform in addition to transmitting
energy to assure an effectively operating system: 1. Lubricating power
2. Resistance to flow
3. Viscosity stability
4. Resistance to oxidation
5. Resistance to fire
2. The friction between two surfaces can easily be reduced by placing a layer of liquid, called a(n) ,
between then: Firm
3. Viscosity: The internal resistance to flow of the molecules of a liquid
4. Name three major problems that may appear if a fluid with too high of a viscosity is used in
a hydraulic system: 1. Higher pressure drops across components
2. An increase in system operating temperature
3. A overall sluggish system operation
5. The pour point of a hydraulic fluid is especially important when a fluid power system is operated in
very weather conditions: Cold
6. The temperature of the fluid in the reservoir of an operating fluid power system is ideally
between F and F: 100 and 140
7. The metal used in fluid power systems that is generally recognized as the greatest promotor to
find deterioration is : Copper
8. Excessive air entrainment and forming may be caused by a variety of hydraulic system design
flaws or operational problems. Name three typical factors that can cause these problems: 1. Leaks
in the lines that operate under atmosphere pressure
2. Air can enter at a pump intel line that's partially able the fluid level cause of the low system
fluid
3. Return lines that end above fluid level because of low fluid levels can cause air to be
chummed into the fluid
9. The temperature at which a fluid is vaporizing rapidly enough to continu- ously burn after a
flame is applied is called the : Fire point
10.A primary disadvantage of petroleum -based hydraulic fluids is low resis- tance to , which
makes them unsuitable in many applications: Fire
11.Hydraulic fluids that use soluble oil to form an oil-in-water emulsion gen- erally have % or less
oil in their formulation: Five
12.Name 3 problems that are commonly associated with the use of fire-resis- tant fluids in hydraulic
systems: 1. Chemical reactions with seats
2. Gaskets and nonferrous metals
3. Environmental toxicity and lower lubricity
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6
, 13.The water content of water-in-oil emulsions is approximately %,
which is considerably lower than both of the soluble-oil emulsion and the high-water-content
fluids: 40
14.Which fire-resistant fluid is similar to automotive antifreeze?: Polyglycol
15.Synthetic fire-resistant hydraulic fluids have several advantages over oth- er fire-resistant fluids.
Name four of these advantages: 1. They have a very high flashpoint
2. They provide excellent fire resistance
3. They function well as hydraulic fluid
4. They are a good lubricant component
16. agents prevent metal-to-metal contract by forming protective coating on the internal parts
of components: Extreme pressure
17.The additive that allows a hydraulic fluid to flow more freely at low temper- atures is known as
a(n) despressant: Pour point
18.Decreasing allows antifoaming agents to reduce the formation of bubbles and
form a hydraulic system reservoir: Surface tension
19. is also called dynamic viscosity: Absolute viscosity
20.Kinematic viscosity is measured with the aid of a device called a(n) -
: Capillary viscometer
21.The ISO viscosity rating system groups fluids into 20 grades, each of which may have a kinematic
viscosity variation of plus or minus % from the
stated grade number: 10
22.The system that indicates hydraulic fluid viscosity by the time it takes 60 mL of the fluid to
flow through a calibrated orifice is called the
system: Saybolt Universal Viscosity
23.Blowing air through a hydraulic fluid at a measured rate and given time pe- riod is used to
determine the characteristics of the material: Foaming
24.List three reasons it is important to properly handle and maintain hydraulic fluids: 1. They reduce
cost of new replacement fluid
2. They reduce the time maintenance personal spreads in a flushing system and changing
fluid
3. They extend the service of the fluid power system
25.The frequency of the hydraulic system fluid quality inspections should be determined by the type
of and the intensity of : Equipment and the intensity of operation
26.The first step in testing a hydraulic fluid is to compare a sample taken from a reservoir with a
sample of unused flid of the same type and grade using a(n)
inspection: Visual
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ANSWERS #11
1. Name five functions that the fluid in a hydraulic circuit must perform in addition to transmitting
energy to assure an effectively operating system: 1. Lubricating power
2. Resistance to flow
3. Viscosity stability
4. Resistance to oxidation
5. Resistance to fire
2. The friction between two surfaces can easily be reduced by placing a layer of liquid, called a(n) ,
between then: Firm
3. Viscosity: The internal resistance to flow of the molecules of a liquid
4. Name three major problems that may appear if a fluid with too high of a viscosity is used in
a hydraulic system: 1. Higher pressure drops across components
2. An increase in system operating temperature
3. A overall sluggish system operation
5. The pour point of a hydraulic fluid is especially important when a fluid power system is operated in
very weather conditions: Cold
6. The temperature of the fluid in the reservoir of an operating fluid power system is ideally
between F and F: 100 and 140
7. The metal used in fluid power systems that is generally recognized as the greatest promotor to
find deterioration is : Copper
8. Excessive air entrainment and forming may be caused by a variety of hydraulic system design
flaws or operational problems. Name three typical factors that can cause these problems: 1. Leaks
in the lines that operate under atmosphere pressure
2. Air can enter at a pump intel line that's partially able the fluid level cause of the low system
fluid
3. Return lines that end above fluid level because of low fluid levels can cause air to be
chummed into the fluid
9. The temperature at which a fluid is vaporizing rapidly enough to continu- ously burn after a
flame is applied is called the : Fire point
10.A primary disadvantage of petroleum -based hydraulic fluids is low resis- tance to , which
makes them unsuitable in many applications: Fire
11.Hydraulic fluids that use soluble oil to form an oil-in-water emulsion gen- erally have % or less
oil in their formulation: Five
12.Name 3 problems that are commonly associated with the use of fire-resis- tant fluids in hydraulic
systems: 1. Chemical reactions with seats
2. Gaskets and nonferrous metals
3. Environmental toxicity and lower lubricity
1/
6
, 13.The water content of water-in-oil emulsions is approximately %,
which is considerably lower than both of the soluble-oil emulsion and the high-water-content
fluids: 40
14.Which fire-resistant fluid is similar to automotive antifreeze?: Polyglycol
15.Synthetic fire-resistant hydraulic fluids have several advantages over oth- er fire-resistant fluids.
Name four of these advantages: 1. They have a very high flashpoint
2. They provide excellent fire resistance
3. They function well as hydraulic fluid
4. They are a good lubricant component
16. agents prevent metal-to-metal contract by forming protective coating on the internal parts
of components: Extreme pressure
17.The additive that allows a hydraulic fluid to flow more freely at low temper- atures is known as
a(n) despressant: Pour point
18.Decreasing allows antifoaming agents to reduce the formation of bubbles and
form a hydraulic system reservoir: Surface tension
19. is also called dynamic viscosity: Absolute viscosity
20.Kinematic viscosity is measured with the aid of a device called a(n) -
: Capillary viscometer
21.The ISO viscosity rating system groups fluids into 20 grades, each of which may have a kinematic
viscosity variation of plus or minus % from the
stated grade number: 10
22.The system that indicates hydraulic fluid viscosity by the time it takes 60 mL of the fluid to
flow through a calibrated orifice is called the
system: Saybolt Universal Viscosity
23.Blowing air through a hydraulic fluid at a measured rate and given time pe- riod is used to
determine the characteristics of the material: Foaming
24.List three reasons it is important to properly handle and maintain hydraulic fluids: 1. They reduce
cost of new replacement fluid
2. They reduce the time maintenance personal spreads in a flushing system and changing
fluid
3. They extend the service of the fluid power system
25.The frequency of the hydraulic system fluid quality inspections should be determined by the type
of and the intensity of : Equipment and the intensity of operation
26.The first step in testing a hydraulic fluid is to compare a sample taken from a reservoir with a
sample of unused flid of the same type and grade using a(n)
inspection: Visual
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6
