3-22.
3-23.
3-24.
3-25.
3-26.
The globe valve gets its name
from the globular shape of its
body, a shape that is unique to
this valve.
1.
True
2.
False
Approximately how far must the
handwheel of a globe valve be
turned toward the closed position
after the valve has been fully
opened?
1.
1/4 turn
2.
1/2 turn
3.
3/4 turn
4.
7/8 turn
What type of flow control valve
makes the most suitable throttle
valve?
1.
Gate
2.
Plug
3.
Globe
4.
Needle
Learning Objective:
Relate the
operation, functions,
requirements, and construction
characteristics of pressure
control devices to fluid power
systems.
Relief valves are used for which
of the following functions?
1.
To maintain pressures above a
predetermined level
2.
To maintain fluid flow below
a predetermined rate
3.
To prevent pressure from
rising above a predetermined
level
4.
To prevent thermal expansion
of the fluids
If a fluid power system uses two
or more relief valves, they must
all be the same size.
1.
True
2.
False
3-27.
Chatter in a relief valve is the
result of
1.
rapid opening and closing of
the valve as it ‘hunts- above
and below a set pressure
2.
too much difference between
opening and closing pressures
of the valve
3.
concurrent operation of the
small relief valve and the
main relief valve
4.
improper seating of the valve
element
REFER TO FIGURE 6-13 IN YOUR TEXTBOOK IN
ANSWERING QUESTIONS 3-28 AND 3-29
CONCERNING THE OPERATION OF A COMPOUND
RELIEF VALVE.
3-28.
When the system pressure
increases above the pressure to
which the valve is set, the main
valve opens
1.
independently of the pilot
valve
2.
only after the system
pressure increases to more
than can be relieved by the
pilot valve
3.
concurrently with the pilot
valve
4.
every time the pilot valve
opens but at a predetermined
time interval afterward
3-29. After the main valve has relieved
the system and when pressure
returns to normal, what does
pilot valve do?
1.
2.
3.
4.
It remains open until after
the main valve closes
It closes simultaneously
the main valve
It closes first and allows
pressure to equalize above
and below the main piston
It closes first and causes
pressure above the main
piston to force the main
valve closed
the
with
18
