Module 7 Flashcards Preview

MT 108 Chapter 3 > Module 7 > Flashcards

Flashcards in Module 7 Deck (31):
1

a valve that limits and regulates the pressure and controls the flow rates of fluid in a hydraulic system

Pressure-control valve

2

a valve that protects a hydraulic system against excess pressure by gradually opening to relieve pressure

Pressure-relief valve

3

a valve used when it is necessary to have one cylinder actuated either before or after another

Sequence valve

4

a valve used to support a hoisted load or to prevent uncontrolled fall

Counterbalance valve

5

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

6

Do pressure-control valves have any partially open positions between fully closed and fully open?

Yes

7

Are pressure-relief valves normally open or normally closed?

Normally closed

8

Name the two general categories into which all relief valves can be divided.

Direct-acting, Pilot-operated

9

Direct-acting poppet relief valves are held in the normally closed position by a(n) _____.

Spring

10

The difference between the set (maximum) pressure point and the cracking-pressure point for a relief valve is called the _____.

Operating differential pressure

11

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

12

What type of valves are used when it is necessary to have one cylinder actuated either before or after another?

Sequence

13

An adjustable back-pressure or braking valve is usually called a(n) _____ valve.

Counterbalance

14

A valve that is similar to a counterbalance valve, but which offers less resistance to return flow, is a(n) _____.

Holding

15

Unloading valves are commonly used in hydraulic systems that have more than one _____.

Pump

16

Is a pressure-reducing valve used to limit the pressure in one part of the system only or in the entire system?

One part

17

Hydraulic shock in a system is usually controlled by a(n) _____.

Shock suppressor

18

The speed at which an actuator moves is determined by the amount of _____.

Fluid flow

19

Name the three ways in which a flow-control valve can operate.

Meter in, Meter out, Bleedoff

20

A pressure-compensation valve is controlled by pressure on the _____ side of the valve.

Downstream

21

Temperature-compensation valves are usually equipped with an element that _____ as the temperature rises.

Expands

22

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

23

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

24

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

25

A counterbalance valve is usually constructed as a
a. double poppet
b. double spool
c. single poppet
d. single spool

a. Double poppet

26

Unloading valves are usually made for _____ operation.
a. direct-acting
b. manual
c. pilot
d. presssure

c. Pilot

27

Pressure-reducing valves limit pressure
a. at the pump
b. in one part of the system
c. in two separate parts of the system
d. throughout the entire system

b. In one part of the system

28

Hydraulic shock in a system is controlled by a(n)
a. adjustable orifice
b. counterbalance valve
c. shock suppressor
d. unloading valve

c. Shock suppressor

29

The speed of a hydraulic actuator is controlled by what characteristic of the hydraulic system?
a. Flow
b. Pressure
c. Temperature
d. Viscosity

a. Flow

30

A flow-control valve can be positioned to operate in all of the following ways except
a. bleedoff
b. counterbalance
c. meter in
d. meter out

b. Counterbalance

31

A pressure-compensation valve senses pressure at the
a. downstream valve outlet
b. pump
c. reservoir
d. valve inlet

a. Downstream valve outlet