Water Columns and Gage Glasses

Question 1

The following condition may be encountered in level
measurement and indication:
a) solids or liquids
b) extremes of heat and cold
c) pressure variations
d) corrosive and explosive conditions
e) all of the above

Answer 1

e) all of the above

Question 2

Separately mounted gage glasses are used to provide a
\_\_\_\_\_\_\_\_\_\_ indication of level over a certain vertical
distance on the vessel.
a) point
b) continuous
c) diagonal
d) ultrasonic
e) indirect

Answer 2

a) point

Question 3

The main operating element of a Hopkinson remote water level
indicator is a
a) Bourdon tube
b) Ledoux bell
c) float
d) capsule
e) large diaphragm

Answer 3

e) large diaphragm

Question 4

When a differential head meter is used to measure water level
in a boiler steam drum, the connection to the steam space
a) forms the variable leg of the meter
b) is cross connected to the constant or reference leg of
the meter
c) is the low pressure side of the meter
d) has a varying water level
e) forms the constant or reference leg of the meter

Answer 4

e) forms the constant or reference leg of the meter

Question 5

Dirt traps are installed on an “Igema” remote water-level
indicator
a) because of the high amount of suspended solids collecting
in the constant head
b) to prevent mixing of the indicating liquid with boiler
water
c) to prevent indicating liquid contamination
d) so that overfilling of the indicating section is
prevented
e) to prevent osmosis from occurring

Answer 5

c) to prevent indicating liquid contamination

Question 6

A great advantage of an Igema level indicator over a
Hopkinson unit is
a) it has the highest degree of accuracy
b) it is the least costly to purchase
c) its ability to show steam and water as different colours
d) there are no moving parts
e) it requires no electricity

Answer 6

d) there are no moving parts

Question 7

A gage glass which shows a clear liquid as being very dark is
the
a) Hopkinson indicator
b) Igema indicator
c) tubular gage glass
d) reflex gage glass

Answer 7

d) reflex gage glass

Question 8

In a high pressure horizontal firetube steam boiler, the bottom
of the gauge glass should be \_\_\_\_\_\_\_\_\_\_\_\_ above the lowest
permissible water level in the boiler.
a) 1 m
b) 50 cm
c) 47 cm
d) 25.4 mm
e) 51 mm

Answer 8

e) 51 mm

Question 9

If a gage glass breaks, the operator shall immediately

a) shut the boiler down
b) add more water to the boiler
c) shut off the steam valve and water valve on the gage
d) lift the safety valve
e) shut the boiler down

Answer 9

c) shut off the steam valve and water valve on the gage

Question 10

Try cocks are
a) used to blowdown the gage glass
b) for checking water level while the gage glass is out of
service
c) for draining the gage glass
d) operated simultaneously
e) on the water column drain line

Answer 10

b) for checking water level while the gage glass is out of

Question 11

How many try cocks are installed on the water column of
a boiler, with over 9.3 square metres heating surface?
a) 1
b) 2
c) 3
d) 4
e) 6

Answer 11

c) 3

Question 12

When a firetube boiler is filled for the first time, it
should be confirmed that when the water first appears
in the gage glass, that there is _______ mm of water
over the top of the tubes.
a) 25.4 mm
b) 50.8 mm
c) 84 mm
d) 101.6 mm
e) 76 mm

Answer 12

e) 76 mm

Question 13

Safety shutoff devices are found
a) on water supply systems feeding a boiler
b) on all gage glasses which are under continuous
supervision
c) only on vessels containing toxic liquid
d) on the constant or “reference” lines to remote indicators
e) on gage glasses not under constant supervision

Answer 13

e) on gage glasses not under constant supervision

Question 14

Tubular gage glasses

a) are suitable for pressures up to 2,800 kPa
b) do not corrode due to high alkalinity
c) indicate the level most accurately
d) can be of any length
e) are not weakened by misalignment

Answer 14

a) are suitable for pressures up to 2,800 kPa

Question 15

Gage glasses show a water level which is
a) slightly less than the level if the vessel is at a lower
temperature
b) the same if all liquids have the same temperature
c) slightly higher than boiler level when the pressure is
high
d) slightly lower when the glass water density is higher
e) the actual vessel level regardless of pressure,
temperature or density differences

Answer 15

d) slightly lower when the glass water density is higher

Question 16

When the water connection between boiler and gage glass becomes
plugged, the water level in the glass will show a level after
a while, that is
a) higher than the level in the boiler
b) lower than the level in the boiler
c) the same as the level in the boiler
d) fully filled
e) lower than the bottom of the sight glass

Answer 16

a) higher than the level in the boiler