Unit 6 Review: Chapter 27 - 31

Question 1

Misalignment of shafts connected by rigid couplings does NOT cause:
Select one:

A. Low pump flows

B. Overheating of bearings

C. Excessive wear of the bearings

D. Shaft failure, vibrations and noise

E. Increased power consumption

Answer 1

A. Low pump flows

Question 2

Generally, positive displacement compressors favor:
Select one:

A. Speed

B. Time

C. Pressure

D. Temperature

E. Volume

Answer 2

C. Pressure

Question 3

The sum of static head and dynamic head is the:
Select one:

A. Static suction head

B. Static suction lift

C. Total static head

D. Total head

E. Static discharge head

Answer 3

D. Total head

Question 4

An air receiver is a pressure vessel whose specifications must conform to the:
Select one:

A. ASME Code, Section VI

B. ASME Code, Section VIII

C. ASME Code, Section I

D. ASME Code, Section IV

E. ASME Code, Section III

Answer 4

B. ASME Code, Section VIII

Question 5

Lubricating oil is necessary in an air compressor to perform the following functions except:
Select one:

A. To provide seating

B. To reduce corrosion

C. To reduce friction

D. To remove heat

E. To prevent wear

Answer 5

A. To provide seating

Question 6

Mechanical seals have all the following advantages over packing except that they:
Select one:

A. Reduce leakage to a minimum

B. Are less expensive than packing

C. Can work under very high temperatures and pressures

D. Do not produce wear on shafts

E. Requires less maintenance

Answer 6

B. Are less expensive than packing

Question 7

One of the disadvantages of using compressed air to drive tools and other machinery over the use of electricity or steam is:
Select one:

A. Compressed air tools are that they are usually more expensive

B. Compressed air machines cannot be damaged by overloading

C. Air driven hand tools do not create a shock hazard

D. Air driven hand tools are lighter in weight

E. Air driven hand tools do not become hot after extensive use

Answer 7

A. Compressed air tools are that they are usually more expensive

Question 8

As the temperature decreases the oil will become:
Select one:

A. Thinner and less viscous (viscosity will be increased)

B. Thicker and less viscous (viscosity will be increased)

C. Thicker and more viscous (viscosity will be decreased)

D. Thinner and more viscous (viscosity will be increased)

E. Thicker and more viscous (viscosity will be increased)

Answer 8

E. Thicker and more viscous (viscosity will be increased)

Question 9

An example of a dynamic compressor is the _____ compressor.
Select one:

A. Rotary screw

B. Axial flow

C. Sliding vane

D. Rotary lobe

E. Reciprocating

Answer 9

B. Axial flow

Question 10

A more suitable design of thrust bearing has the bearing surfaces in the form of pads, in which
Select one:

A. There is no room for an oil wedge to form

B. The pads are free to tilt

C. The thrust collar tilts against against a stationary surface

D. The pads press against each other in opposite directions

E. The thrust collar does not revolve

Answer 10

B. The pads are free to tilt

Question 11

A centrifugal pump that has high suction lift and a resulting negative casing pressure will likely have:
Select one:

A. No need for a shaft sleeve

B. A lantern ring or seal cage in the stuffing box

C. Wear rings installed

D. No leakage from a lantern equipped stuffing box

E. A special shaft sleeve

Answer 11

B. A lantern ring or seal cage in the stuffing box

Question 12

One of the categories of air compressors is the _____ type.
Select one:

A. Reciprocating

B. Centrifugal

C. Positive displacement

D. Rotary lobe

E. Rotary screw

Answer 12

C. Positive displacement

Question 13

Shell, sleeve or journal bearings are usually constructed with a _____ lining, commonly called Babbitt, carried on a cast iron or steel housing.
Select one:

A. White-metal alloy

B. Aluminum-metal alloy

C. Brass-metal alloy

D. Lead-metal alloy

E. Bronze-metal alloy

Answer 13

A. White-metal alloy

Question 14

What size packing should be used if the stuffing box bore on a pump is 63.5 mm (2.5 in.) and the shaft diameter is 50.8 mm (2 in.)?
Select one:

A. 4.76 mm (3/16 in)

B. 12.7 mm (1/2 in)

C. 9.525 mm (3/8 in)

D. 6.35 mm (1/4 in)

E. 19.05 mm (3/4 in)

Answer 14

D. 6.35 mm (1/4 in)

Question 15

One of the most common designs of a rotary compressor is the _____ type.
Select one:

A. Positive displacement

B. Rotary lobe

C. Centrifugal

D. Turbine

E. Axial flow

Answer 15

B. Rotary lobe

Question 16

Usually the cause of the bearing trouble is one of the following:
Select one:

A. Proper viscosity of oil

B. True alignment of shaft and bearing

C. Proper bearing design

D. Temperature of oil too low

E. Loss of oil supply

Answer 16

E. Loss of oil supply

Question 17

A common arrangement for temperature control is to _____ the lubricant to the bearing where it picks up heat.
Select one:

A. Circulate generous quantities of

B. Circulate minimal quantities of

C. Air cool

D. Water cool

E. Use higher viscosity

Answer 17

A. Circulate generous quantities of

Question 18

High operating temperatures can cause premature bearing failure due to:
Select one:

A. Hard pieces of lubricant being pressed into the bearing surfaces producing flaking and pitting

B. Uneven loading of the bearing

C. The softening of the metal

D. Excessive vibrations

E. Cracking or splitting of the bearing race

Answer 18

C. The softening of the metal

Question 19

Some uses of compressed air in buildings include all of the following except:
Select one:

A. Atomizing fuel oil

B. Starting engines

C. Mixing or agitating in water treatment processes

D. Extinguishing fires in buildings.

E. Operating building environmental control systems

Answer 19

D. Extinguishing fires in buildings.

Question 20

Which statement is NOT correct about a simple type of thrust bearing known as a collar thrust bearing?
Select one:

A. There is no room for an oil wedge to be formed

B. This bearing can only carry a limited load

C. The collars have their complete area pressing against the bearing surface

D. The collars function like a tilting pad

E. The collars are an integral part of the shaft

Answer 20

D. The collars function like a tilting pad