Module 6 Flashcards
The lowest fluid pressure that will open a check valve
Cracking pressure
A valve in which the flow is blocked when the valve is in a nonactuated position
Normally closed valve
A valve that permits fluid to flow when the valve is in a nonactuated position
Normally open valve
Directional-control valves can be operated _____ or _____.
Manually; Automatically
Directional-control valves are classified by the way the fluid flows when the valve is in the _____ position.
Center
Many manually operated tow-way valves are not suitable for hydraulic service because of their low _____ ratings.
Pressure
One disadvantage of needle valves is that they usually have high _____.
Pressure losses
A direct-acting solenoid valve is a normally _____ valve.
Closed
Automatic solenoid valves that operate in high-pressure hydraulic systems are usually _____-operated.
Pilot
A two-way check valve permits fluid flow in _____ direction(s).
One
The lowest pressure at which a check valve will open is its _____ pressure.
Cracking
A three-way diverter valve controls a hydraulic motor by serving as either an unloading device or a simple _____ valve.
On/Off
A normally open three-way valve permits flow to the cylinder when the valve is in a(n) _____ position.
Nonactuated
A four-way valve has _____ primary working connections.
Four
Most four-way valves are manufactured with _____ operating positions.
Three
A three-position, four-way valve is called a(n) _____ valve.
Closed crossover
A five-way valve is usually a variation of a(n) _____ valve.
Four-way
Are the exhaust ports connected internally in a five-way valve?
No
A four-way spool valve that does not shift with a linear motion is a(n) _____ valve.
Rotary
Directional-control valves do all of the following except
a. control fluid flow
b. move hydraulic cylinders
c. relieve excess pressure
d. stop hydraulic cylinders
c. relieve excess pressure.
Directional-control valves are not classified by the number of
a. paths
b. pipe threads
c. ports
d. positions
b. Pipe threads.
Some manually operated two-way valves are not suitable for hydraulic service because of their
a. low pressure ratings
b. seating design
c. slow closing speeds
d. slow opening speeds
a. Low pressure ratings.
The closing force of a solenoid-operated valve is usually limited to _____ lb.
a. 5
b. 15
c. 25
d. 35
b. 15
The pressure at which a check valve will start to open is called its
a. cracking pressure
b. popping pressure
c. pressure rating
d. seating pressure
a. Cracking pressure.
Spool valves usually are partially balanced because of their
a. actuator type
b. body size
c. construction
d. number of internal ports
c. Construction.
Three-way spool valves are made with three
a. basic parts
b. primary and three secondary connections
c. primary connections
d. secondary connections
c. Primary connections.
Selector and diverter three-way valves differ from directions-control valves in their
a. internal construction
b. number of piping connections
c. pilot connections
d. pressure ratings
a. Internal construction.
A three-position, four-way valve is referred to as a _____ valve.
a. closed crossover
b. direct control
c. needle
d. split-phase
a. Closed crossover.
Rotary spool valves can be manufactured to operate as all of the following except _____ valves.
a. two-way
b. three-way
c. four-way
d. five-way
d. Five-way.
