Module 6 Flashcards
a valve used in a pneumatic system to direct the airflow from one place to another to permit the actuating parts to perform their work
Control valve
the lowest pressure that will open a valve
Cracking pressure
a valve having three primary connections on the outside of the valve body, and three ports inside the valve
Three-way valve
a valve with four primary connections and either four or five external ports
Four-way valve
a special four-way valve with five external connections, all connected to primary system connections
Five-way valve
Name the four methods of identifying control valves.
Number of primary connecting ports
Number of control positions
Type of control element
Method of operation
If not properly sized, globe valves can cause _____ flow.
Turbulent
A gate valve should not be used for _____ flow.
Throttling or Regulating
Needle valves used for regulating flow have high _____ losses.
Pressure
The most common method of controlling automatically operated valves is with electric _____.
Solenoids
Two-position automatically operated valves are classified as being normally _____ or normally _____.
Open, Closed
Large quantities of high pressure air are best controlled by solenoid valves that are _____-operated.
Pilot
Check valves are classified as automatic two-way, two-_____ valves.
Position
A disadvantage of two-way spool valves is that they are not always _____.
Pressure Balanced
Three-way valves have three _____ or working connections.
Primary
The most common application of a two-position, three-way valve is in _____ control.
Directional
Three-way valves having a blocked center position are usually made to center _____.
Automatically
When compressed air completes its work it is usually _____ to the atmosphere.
Exhausted or Vented
Four-way valves reduce the total number of _____ in a system.
Controls
Airflow in a nonactuated two-position, four-way valve flows in _____ direction(s).
Two
The centering of a three-position, four-way valve is usually accomplished by _____.
Springs
A manually operated flow control valve may be further identified by all of the following except
a. number of connecting ports
b. number of control positions
c. pressure capacity
d. type of control element
c. Pressure capacity.
The lowest pressure that will open a check valve is called the _____ pressure.
Cracking
Manually operated stop or isolating valves (globe, gate, or ball) are classed as _____-way valves.
Two
A three-way valve is constructed with three _____.
Primary connections
The high-pressure losses in a needle valve are caused by the _____.
Valve seat
Three-position, three-way valves are usually held in the center position by _____.
Springs
What is the most common method of actuating automatically operated flow control valves?
Electric solenoids
Compressed air returning through a valve after it has done work is often directed to the _____.
Atmosphere
Because a solenoid has limited lifting strength, the valve closing spring in a high-pressure system must be _____ and the valve seat opening _____.
Weak; small
In how many directions can air flow in a nonactuated two-position, four-way valve?
Two
