127

Front 1

The two general groups of fans are:

1) Centrifugal and axial flow

2) Positive displacement and axial flow

3) Reciprocating and centrifugal

4) Rotary positive displacement and centrifugal

5) Reciprocating and axial flow

Back 1

Centrifugal and axial flow

Front 2

The group of fans that consist of a rotor or wheel having several radial blades, which are mounted on a shaft within the fan housing are called:

1) Axial flow fans

2) Archial cage fans

3) None of the above

4) Centrifugal fans

5) Both axial flow and centrifugal fans

Back 2

Centrifugal fans

Front 3

Which of the following statements about fan performance curves is false:

1) The curve is a plot of horsepower against air volume delivery

2) The curve is a plot of static pressure against air volume delivery

3) The curve is a plot of static efficiency against air volume delivery

4) The curve range is from shutoff to free delivery

5) They are plotted from theoretical calculations

Back 3

They are plotted from theoretical calculations

Front 4

The propeller axial flow fan is used:

1) For high capacity, low pressure applications

2) In ducted air distribution systems

3) For low capacity, high pressure applications

4) For high capacity, high pressure applications

5) For low capacity, low pressure applications

Back 4

For high capacity, low pressure applications

Front 5

Backward inclined airfoil fans:

1) Are mostly used for high capacity, high pressure applications

2) Are mostly used for low capacity, high pressure applications

3) Have a lower initial cost than the plain backward inclined fan

4) Are less efficient than the plain backward inclined fan

5) Are mostly used for high capacity, low pressure applications

Back 5

Are mostly used for high capacity, high pressure applications

Front 6

What are the three different kinds of pressure developed by a fan?

1) Static pressure, head pressure, total pressure

2) Static pressure, velocity pressure, total pressure

3) Static pressure, head pressure, suction pressure

4) Velocity pressure, head pressure, suction pressure

5) Head pressure, suction pressure, total pressure

Back 6

Static pressure, velocity pressure, total pressure

Front 7

Axial flow fans are classified as:

1) Tube axial and rotary positive displacement

2) Vane axial and centrifugal

3) Vane axial, tube axial, and propeller

4) Centrifugal and propeller

5) Centrifugal and turbine

Back 7

Vane axial, tube axial, and propeller

Front 8

The fan that discharges maximum air delivery at the lowest power requirement and is used mainly to produce large air movements at low pressures is the:

1) Tube axial fan

2) Propeller fan

3) Backward inclined blade fan

4) Radial blade fan

5) Forward curved blade fan

Back 8

Propeller fan

Front 9

Total pressure exerted by the air is the sum of:

1) Suction pressure and velocity pressure

2) Head pressure, suction pressure, and velocity pressure

3) Static pressure and velocity pressure

4) Head pressure and velocity pressure

5) Head pressure and suction pressure

Back 9

Static pressure and velocity pressure

Front 10

Axial flow fans:

1) Are not the logical choice to move large volumes of air at low pressures

2) Have minimum horsepower at maximum or free air delivery

3) Are the least economical fans used to produce high capacity, low pressure air movement

4) Are quieter than centrifugal fans

5) Have maximum horsepower requirements at maximum or free air delivery

Back 10

Have minimum horsepower at maximum or free air delivery

Front 11

Two fan wheels are rotating at the same speed One wheel has forward curved blades and the other has backward inclined blades. The velocity of the air leaving the forward curved blades is considerably higher for which of the following reasons?

1) The air resistance of the backward inclined blades is much lower

2) The inclination of the blades in the forward curved fan increases the resultant force vector while the backward inclined blade inclination decreases the resultant vector

3) All of the above

4) The centrifugal force of the forward curved blades is higher

5) The forward motion of the forward curved blades is higher

Back 11

The inclination of the blades in the forward curved fan increases the resultant force vector while the backward inclined blade inclination decreases the resultant vector

Front 12

Control of the static pressure and horsepower requirements at a given speed is obtained by using:

1) Belt guards

2) Outlet damper control

3) Variable inlet vane control

4) Fluid drives

5) Direct drives

Back 12

Variable inlet vane control

Front 13

When a fan outlet is considered fully open which of the following statements is true?

1) The pressure volume curve of a backward inclined fan increases

2) Vane axial fans have maximum horsepower requirements

3) There is free air volume delivery

4) The power requirements for a forward curved fan are at a minimum

5) Air volume delivery is considered a minimum

Back 13

There is free air volume delivery

Front 14

Forward curved centrifugal fans:

1) Are quieter than backward inclined fans

2) Require less horsepower than backward inclined fans to deliver a specified air volume

3) Are more efficient than backward inclined fans

4) Operate at a higher speed than backward inclined fans for the same air volume

5) Operate at a lower speed than backward inclined fans for the same air volume

Back 14

Operate at a lower speed than backward inclined fans for the same air volume

Front 15

Forward curved fans:

1) Are more desirable for large fans

2) Require larger size shafts than backward inclined fans

3) Are desirable when air handling units have two or more fans mounted on a common shaft

4) Are quieter than backward inclined fans

5) Operate at higher speeds than backward inclined fans

Back 15

Are desirable when air handling units have two or more fans mounted on a common shaft