Module 7 Flashcards
a valve that limits and regulates the pressure and controls the flow rates of fluid in a hydraulic system
Pressure-control valve
a valve that protects a hydraulic system against excess pressure by gradually opening to relieve pressure
Pressure-relief valve
a valve used when it is necessary to have one cylinder actuated either before or after another
Sequence valve
a valve used to support a hoisted load or to prevent uncontrolled fall
Counterbalance valve
a valve used to limit the pressure in one part of the system to below that of the main part of the system
Pressure-reducing valve
Do pressure-control valves have any partially open positions between fully closed and fully open?
Yes
Are pressure-relief valves normally open or normally closed?
Normally closed
Name the two general categories into which all relief valves can be divided.
Direct-acting, Pilot-operated
Direct-acting poppet relief valves are held in the normally closed position by a(n) _____.
Spring
The difference between the set (maximum) pressure point and the cracking-pressure point for a relief valve is called the _____.
Operating differential pressure
When a relief valve is controlled from a remote point, is the main valve usually a single-stage or a two-stage valve?
Two-stage
What type of valves are used when it is necessary to have one cylinder actuated either before or after another?
Sequence
An adjustable back-pressure or braking valve is usually called a(n) _____ valve.
Counterbalance
A valve that is similar to a counterbalance valve, but which offers less resistance to return flow, is a(n) _____.
Holding
Unloading valves are commonly used in hydraulic systems that have more than one _____.
Pump
Is a pressure-reducing valve used to limit the pressure in one part of the system only or in the entire system?
One part
Hydraulic shock in a system is usually controlled by a(n) _____.
Shock suppressor
The speed at which an actuator moves is determined by the amount of _____.
Fluid flow
Name the three ways in which a flow-control valve can operate.
Meter in, Meter out, Bleedoff
A pressure-compensation valve is controlled by pressure on the _____ side of the valve.
Downstream
Temperature-compensation valves are usually equipped with an element that _____ as the temperature rises.
Expands
A pressure-reducing valve is a normally _____ valve.
a. closed three-way
b. closed two-way
c. open three-way
d. open two-way
d. Open two-way
What is another term for the maximum pressure of a poppet relief valve?
a. Cracking pressure
b. Flow capacity
c. Operating differential pressure
c. Set pressure
d. Set pressure
What is the pressure at the discharge (outlet) of a sequence valve?
a. cracking pressure
b. Line pressure
c. Negative pressure
d. Set pressure
b. Line pressure
