Valves
Valves
Training Manual
1
Valves
Valves
Training Manual
This manual was prepared and published by:
Numatics, Inc.
1450 North Milford Road
Highland, MI 48357
248-887-4111
Copyright © 2005 by Numatics, Inc...
All rights reserved. ISBN 0-000000-00-0
Printed in U.S.A.. OM- 11/94
2
Valves
Basic Information
What is a Valve?
A mechanical device used to direct the flow of a fluid -- pneumatic directional control valves are used to direct air flow.
Valves are described by:
• Flow directions
• Normal or start condition • Number of ports
• Operator type
• Number of positions
OR
Valves are defined by their respective symbol 3
Valves
Symbology
CONCEPT
What is a Symbol?
A graphic representation of an idea.
To understand the symbol, you have to possess some understanding of what the symbol is showing.
4
Valves
Symbology
Flow Paths
With pneumatic symbols, our concern is flow
OUT
A flow path
May be called open or passing
Shows flow in the direction of the arrow -- AND -No flow path
May be called closed or non-
passing
IN
Shows a blocked flow path
At Rest
A valve has two states:
Actuated
Blow
Gun
Blow
Gun
80 PSIG
Force
80 PSIG
5
Valves
Symbology
Basics
Blow Gun
At Rest
Actuated
Non-Passing
Passing
Supply
Is a spring
Is a push button
Blow Gun
• When the button is pushed, air flows through the device
• Release the button, air does not flow through the device because a spring provides a force to return the valve to its initial or original closed condition
• We say: At rest the spring is in command • At rest is the normal position of the valve
• There are two conditions for the blow gun -- each has its own box
• A complete symbol shows both
6
conditions
Valves
Basic Information
2/2
Two Way
2
1
Description
2 Way
2 Position
Normally non-passing
Push button, spring return
2 Ports
•
•
•
2 Flow directions
Actuated/At rest
At start condition
Operator type
1 and 2
Two flow directions -- either passing or non-passing
Start condition (normal or at rest condition) is determined by the spring
Two ports -- although both conditions are shown, the valve shown has only two ports.
The symbol shows the valve as it is (non-passing) and as it can be (passing)
•
Operators appear at both ends of the flow path symbols - When the operator is in command, the flow path next to the operator is caused.
7
Valves
Symbology
Two Way
2/2
2
1
Description
2 Way
2 Position
Normally-passing
Push button, spring return
2 Ports
•
•
•
2 Flow directions
Actuated/At rest
At start condition
Operator type
1 and 2
At rest, this valve allows supply to pass through when actuated, flow is interrupted.
There is no standard for labeling ports that is universally accepted by all manufacturers.
Referred to as 2/2 for two ported/two position without regard for flow path.
8
Valves
Symbology
Operators
Common Pneumatic Operators
• Push Button
• Solenoid
• Air Pilot
• Solenoid/Air
Pilot
• Detent
• Hand Lever
• Cam Roller
• Spring
• Treadle/Foot
Pedal
• Manual
9
Valves
Symbology
Application
Circuit #1
Single acting air cylinder
•
Requires air pressure to extend -- spring will retract the cylinder
•
2
Only one port, rod end open to atmosphere -vented
At Rest
1
•
2
If we push the button, the cylinder extends, compressing the spring
Force
1
Symbol shows valve actuated
IF,
as shown above, we now release the button --after shifting the valve and extending the cylinder …
WHAT
HAPPENS?
Are You Certain?
Why?
10
Valves
Symbology
Va l #1 ve
Application
2
Va l #2 ve
1
2
Note: Arrow has changed direction indicating correct flow direction
1
The only way to retract the cylinder is to exhaust (vent) the trapped air downstream of valve #1
Now -- @ Start:
Valve #1 at rest Cylinder is retracted (spring)
Actuate Valve #1 Cylinder extends
Release Valve #1 Cylinder stays extended
Actuate Valve #2 Cylinder retracts
Release Valve #2 No action
If the cylinder was a double acting air cylinder -- we’d have to do this at both ports… 11
Valves
Symbology
Flow Paths --- Three Way Valves
Combine a normally non-passing 2-position 2way and A normally passing 2-position 2-way
12
Valves
Symbology
3/2
Three Way
2
1
3
Description:
3-Way
3 flow directions
2-Position
Actuated/At rest
Normally Non-Passing
At start condition
Push Button, Spring Return
Operator type
3 Ports
1, 2, and 3
3 Flow Directions ---
Non-passing, flow from 2 to 3, flow from 1 to 2
Start condition determined by spring
3 Ports --- there is no one standard --- may be identified as P, C, E or P, C, X or various other systems. You must verify function --- do not assume! 13
Valves
Symbology
Application
Circuit #2
Retract
Valve
A
Extend
2
2
1
1
Valve
B
3
Note: Supply to both valves is from one source, so pressure at valve A is the same as at valve B
• What is the cylinder’s position at start?
(Start is when we’ve piped the circuit as shown and the first time supply is presented to both valves). • What happens when we actuate only valve
A?
• What happens when we actuate only valve
B?
• What happens when we actuate both valve
A and valve B?
Are You Certain?
Can You Explain Why?
14
Valves
Symbology
3/2
Three Way
2
1
3
Description:
3-Way
3 flow directions
2-Position
Actuated/At rest
Normally Passing
Start condition
Push Button, Spring Return
Operator type
3 Ports
1, 2, and 3
3 Flow Directions ---Non-passing, flow from 1 to 2 flow from 2 to 3
Start condition determined by spring
Ports may be labeled in different ways
15
Valves
Symbology
Application
Circuit #3
Retract
Valve
A
Extend
2
2
1
3
1
Valve
B
3
Note: Supply pressure identical at both valves Observe arrows representing correct flow directions
• What is the cylinder’s position at start?
• What happens when we actuate only valve
A?
• What happens when we actuate only valve
B?
• What happens when we actuate both valve
A and valve B?
16
Valves
Symbology
Application
Circuit #4
Retract
Extend
Weight
Valve
A
2
2
1
3
1
3
Valve
B
Note:
Supply pressure identical at both valves; note also -- piping determines function
Observe arrows representing correct flow directions
• What is the cylinder’s position at start?
• What happens when we actuate only valve
A?
• What happens when we actuate only valve
B?
• What happens when we actuate both valve
A and valve B?
17
Valves
Symbology
Flow Paths --- Four Ported Four Way 4/2
2
1
3
3
2
4
1
2
1
3
Two 3-Ways Combined = One 4-Way, 4-Ported
One Normally Non-Passing 3-Way
+ One Normally Passing 3-Way
= One 4-Ported, 4-Way
18
Valves
Symbology
4/2
Four Way
4-Ported/2-Position
4
2
3
1
Description:
4-Way
4 flow directions
2-Position
Actuated/at rest
Normally Passing Classification N/A
Push Button, Spring Return
Operator type
4 Ports
1, 2, 3, and 4
4 Flow Directions ---1 to 2, 3 to 4, 1 to 4, 2 to 3
Ports may be labeled in various ways. Verify function at each port --- do not assume.
19
Valves
Symbology
4/2
Application
Circuit #5
Retract
Extend
4
2
3
1
Observe arrows indicate correct flow directions • What is the cylinder’s position at start?
• What happens when the valve is actuated? Does the cylinder extend and retract at the same speed?
?
At what point would a metering device need to be installed to make extend and retract speeds identical?
20
Valves
Metering Devices
Flow Controls
Metering Devices: used to restrict flow--- making a cylinder slower ONLY.
Adjustability is determined by a tapered needle valve. Addition of a checked flow path allows a greater flow in one direction “Free Flow” into cylinder.
Restriction +
No Flow
Adjustment =
Flow
Needle Valve
Check Valve
Needle + Check = Flow Control
Restricted
“Free” Flow
Flow Control
FREE FLOW
TO CYLINDER
L
C
CHAPTER 8
\
21
Valves
Symbology
4/2
Application
Circuit #6
Controlling Cylinder
Speed
4
2
3
Objective:
Extend
and retract at the same speed 1
Observe arrows indicate correct flow directions
•
•
•
Flow controls restrict exhaust at each cylinder port. While adjustments can be made to the flow controls to achieve the objective of making extend speed equal to retract speed, there is a penalty for doing so. The cylinder is slowed in both directions (extend more than retract) to make the speeds equal.
Even at “free flow” the flow control is a restriction to flow of the circuit.
What if our objective is to have equal thrust
1
in both directions?
Where would we use a regulator in the circuit? A Regulator
Reduces
Pressure (Force)
22
Valves
Symbology
4/2
Application
Va l A ve
Circuit #7
4
2
Objective:
Extend
and retract with same force
1
2
Va l B ve
3
3
3-way valve used as
Selector
Selects line pressure or 1
1
reduced pressure
•Regulators are not designed for exhausting a cylinder --- unless they are equipped with an “internal check” bypass.
•Do not use a regulator down-stream of a valve without verifying
“check/bypass” function.
Note: Both valves are simultaneously actuated • Which port is the exhaust port for the circuit?
• Regulator is adjusted until extend and retract forces are identical.
23
Valves
Symbology
5/2
Five Ported Four Way
Flow is normally passing from
1 to 2 when this operator is actuated
2
12
14
4
3
Flow is normally passing from
1 to 4 when this operator is actuated 1 5
Description:
4-Way
4 flow directions
2-Position
Actuated/At rest
Normally Passing Classification
N/A
Push Button, Spring Return
Operator type
5 Ports
1, 2, 3, 4, and 5
• Each cylinder port has its own exhaust
Standard labels apply --- ISO standard shown above, may also be:
B A
B
Operator
A
Operator
EB P EA
EB = Exhaust of B
EA = Exhaust of A
(NFPA standard, other labels may be found --- verify function) 24
Valves
Basic Information
5/2
Port Identification
Labeling “Standards”
B A
A
Conventional
NFPA
14
ISO
A
B
Numatrol
EBP EA
2 4
12
3 1 5
2 4
B
1 3 5
A B
A
B
EA P EB
Some
Automotive
Series
25
Valves
Symbology
5/2
Application
Objective: Extend and retract at the same speed Circuit #8
4
2
14
12
5 1 3
NOTE:
•
•
•
Dotted line indicates an assembly --- a modular combination of devices; in this case a valve and a speed control sandwich.
Metering devices are needle valves and serve to restrict only the exhaust --- supply is full flow.
Modular design allows control from the valve (often the cylinder is inaccessible or in a protected cell).
• Only by restricting both exhaust flow paths can we extend and retract at the same speed
26
Valves
Symbology
5/2
Application
Objective: Extend and retract with same force Circuit #9
Is a shorthand symbol
R
2
for a regulator 1
4
12
14
3 1 5
R
R
A means of showing lines that do not connect Lines that do connect
NOTE:
• Dotted line indicates an assembly --- a modular combination of devices; in this case a valve and a double regulator sandwich.
• IMPORTANT! Observe that the addition of the sandwich regulator has altered the valve flow paths. • Modular design allows control from the valve’s location. • A direct acting multi purpose valve can have supply and even different pressures at ports other than 1 or P --- achieving different functions. 27
Valves
Symbology
Common Multi-Purpose Pipings
2-Way NNP
3-Way NNP
Pressure Diverter
2-Way NP
3-Way NP
2 Pressure Selector
R R
Single Pressure
Dual Pressure
R
Double Capacity, NNP 2-Way
R
Double Capacity, NNP 3-Way
28
Valves
Symbology
Double Solenoid Detent
2
Shows which position is in command at start
4
12
5/2
14
3 1 5
DETENT: A means of maintaining position of a spool
Description:
4-Way
4 flow directions
2-Position Detented Held shifted w/momentary signal
Normally Passing Classification
N/A
Double Solenoid
Operator type
5 Ports
1, 2, 3, 4, and 5
• Advantage the detent offers --- valve stays shifted with a momentary pulse to the solenoid --- no need not be held energized.
• Valve has “memory” -- remembers last signal received.
• Useful in sequencing, reducing energy consumption, or as a safety precaution.
29
Valves
Symbology
Application
Circuit #10
Objective: Vacuum cup picks up/blows off part
Vacuum
Source
Small Volume Chamber
2
4
12
14
3 1 5
Plug
R
40 PSI
Vacuum Cup
Regulator adjusts force of
“blow off” --- shown set @ 40 psig Observe flow directions
NOTE:
• Valve in “12” condition has vacuum at the cup and regulated air fills a small volume chamber
• Valve in “14” condition has vacuum blocked and a puff of air breaks the vacuum lock and blows off the part. Force is adjustable.
Volume chamber is sized for requirement of the circuit.
• Valve selected to maintain position in the event of power failure --- double solenoid detent also only requires momentary pulse of electricity • Single valve solution: saves energy, adds fail 30
Valves
Symbology
Application
Circuit #11
Objective: Cylinder Deceleration Circuit or
Varying
Clamp Force
4
2
14
12
Main Valve
5 1 3
4X
2
14
12
5 1 3
R
Selector Valve observe port #4 is plugged
NOTE:
• Cylinder extends and retracts with signal to main valve • Pressure to main valve controlled by selector valve • Cylinder can extend, then, with higher pressure selected, clamp with greater force
• Varying selected pressures can decelerate/accelerate the cylinder
How can we stop the cylinder in mid stroke? 31
Valves
Symbology
5/3
Three Position
3-Position Valves --- All Ports Blocked
2
4
12
14
3-position valves have a center function The center position is described
3 1 5
Springs center valve when not energized
Description:
4-Way
4 Flow Directions
3-Position Spring Center Energized/Center/Energized
All Ports Blocked at Center Describes at rest condition
Double Solenoid
Operator type
5 Ports
1, 2, 3, 4, and 5
Note: Center is often referred to as MID position
• Useful if some condition other than full extend or full retract is desired.
• Most frequently selected to stop or jog an air cylinder. • Be Aware --- there are limitations with potentially serious consequences. Not always a good choice. • Best used to stop an air motor, blow-off or where there is no volume of trapped air.
Note: aHow can volume of air is potential energy trapped you tell the 12 end from the 14 end andvisually? avoided when possible. should be
Double solenoid valves can be difficult to determine flow paths --- always verify function.
32
Valves
Symbology
5/3
Three Position
All Ports Blocked Center
Circuit #12
2
4
12
Objective: Stop the cylinder in mid stroke 14
3 1 5
OBSERVE:
Cylinder will not stop until the back pressure rises high enough to balance the forces on the piston --- analysis follows. •
•
•
•
•
NOTE:
Air is trapped in the cylinder. Any leakage (fittings, piston seal, rod seal, valve) will allow the cylinder to move or drift
When air is exhausted by a lockout or dump valve, air will be trapped in cylinder
If load is vertical --- any cylinder lines’ inadvertent exhaust will cause the load to drop unexpectedly
During start up --- the all ports blocked center valve does not allow the air to pressurize the cylinder. First stroke could be at high speed due to potential lack of air at either end of cylinder
Disconnecting any air lines for maintenance may cause unexpected rapid movement of the cylinder
--- even if OHSA lock out has been correctly actuated These actions may occur when least
33
Valves
Symbology
Application
Circuit #12 --- Analysis --- Part One
In Motion
75* PSIG
2
4
Energized 12
30 PSIG
14
3
80 PSIG Supply
1
5
75 PSIG Extend
30 PSIG Exhaust Back Pressure
P = 45 PSI ---- Net Thrust
* 75 PSIG (not 80 PSIG) due to line loss, fittings, valve inefficiencies NOTE: The cylinder is in the process of extending.
In a moment, we’ll try to stop that movement.
There is resistance to movement in the cylinder caused by the air trying to exhaust. At this exact moment we have a net extend force (Thrust) of 45 psig pushing on the piston.
Now we’ll try to stop the cylinder.
34
Valves
Symbology
Application
Circuit #12 --- Analysis --- Part Two
Inertia -- a body in motion wants to stay in motion INERTIA
75 PSIG
2
4
30+ PSIG
“Stop” Condition
3 15
80 PSIG Supply
NOTE: Force is a result of Pressure times Volume
(another way of thinking about Area).
On the ROD SIDE, Force will increase as volume is reduced.
On the BLIND SIDE, Force will decrease as volume is provided.
Once the Forces are equal, the cylinder will stop. NOTE: often forces do not equal within a small cylinder body, but will complete end of stroke due to Therefore: Load cannot “stop” immediately the volume of air in the tube between the valve and cylinder.
The Larger the P = The Greater the Over-travel
35
Valves
Symbology
5/3
Three Position
3-Position Valves
---
and
2
Cylinder ports pressurized exhaust ports blocked
4
12
14
3 1 5
NOTE: Description related to center position
Description:
4-Way
4 Flow Directions
3-Position, Spring Center Energized/Center/Energized
Exhaust Blocked, Cylinder
Describes at rest condition
Ports Pressurized
Double Solenoid
Operator type
5 Ports
1, 2, 3, 4, and 5
Note: Most often used with single pressure piping to stop and hold a balanced cylinder, such as rodless or double-rodded cylinder in a mid-position, with a mechanical rod-lock or carriage-lock.
36
Valves
Symbology
5/3
Three Position
3-Position Valves
2
---
Supply blocked, cylinder ports exhausted 4
12
14
3 1 5
NOTE: Description related to center position
Description:
4-Way
3-Position, Spring Center
Supply Blocked, Cylinder
Ports Exhausted
Double Solenoid
5 Ports
4 Flow Directions
Energized/Center/Energized
Describes at rest condition
Operator type
1, 2, 3, 4, and 5
Note: Most often used with dual pressure piping to stop and hold a double acting cylinder in a mid-position, with a mechanical rod-lock.
37
Valves
Symbology
5/3
Application
Circuit #13
Objective: Stop the cylinder in mid stroke
2
4
12
14
3 1 5
OBSERVE: Cylinder will over-travel and not hold position against external loads
•
•
•
NOTE:
If cylinder is in mid position, actuating the valve will cause rapid (potentially dangerous) movement due to large ΔP
Not suitable for vertical loads
Desirable only for specific applications where center position function applies
What if the valve was able to be piped in another way? 38
Valves
Symbology
Application
Circuit #14
Objective: Stop the cylinder in mid stroke
2
4
12
OBSERVE: Center position of valve shows being piped with supply to ports #3 and #5
14
3 1 5
R
R
Available as an assembly --module that installs between valve and base
NOTE:
• Check valves stop and hold cylinder in mid position
• Two regulators balance pressures
• In case of electrical failure, valve defaults to mid position, check valves stop and maintain cylinder position • In case of pneumatic supply failure, valve defaults to mid position, check valves stop and maintain cylinder position
• During start up, first cycle does not cause rapid cylinder motion as pressure is present on both sides of the piston
• Be aware that air will be trapped even if an exhaust or lock out valve is opened upstream
39
of this valve
Valves
Symbology
Application
Circuit #15
Objective: Stop the cylinder in mid stroke
2
4
12
OBSERVE: Center position of valve shows being piped with supply to ports #3 and #5
14
3 1 5
R
R
Available as an assembly --module that installs between valve and base
NOTE:
• Two regulators balance pressures
• In case of electrical failure, valve defaults to mid position, dual pressure stops and maintains cylinder position
• During start up, first cycle does not cause rapid cylinder motion as pressure is present on both sides of the piston
• The Quad-check prevents any back flow of air through the regulators, while providing an exhaust path for air during a lock-out procedure after an “estop.”
• Should always be applied with a mechanical rodlock on double acting cylinders.
40
Valves
Construction
Actuation Methods
2 4
3 1 5
2 4
3 1 5
2 4
3 1 5
MANUAL (Direct Acting)
Force to shift valve supplied by mechanism -- linkage directly acts on valve
SOLENOID (Direct Acting)
Electromagnet pushes valve. Force is supplied by electrical current -- wattage
SOLENOID AIR PILOT
(Direct Acting
Solenoid Powers Air
Pilot Valve)
Solenoid air pilot requires minimum supply pressure, or, if not available --- must be externally supplied. Typically, internal supply provided only when supply is provided at port #1. Uses air pressure at inlet to shift main valve element.
41
Valves
Construction
Direct Acting
2 4
12
14
3 1 5
Symbol shows solenoid and direct acting manual override
NOTE: Flow path arrows omitted to show multi purpose nature of valve. How the valve is piped will determine flow paths.
Action: Solenoid pushes spool directly, compressing spring
ADVANTAGES:
• Valve shifting force is independent from supply pressure -- allows multi purpose piping of valve --- constant solenoid force
• Simple design --- three moving parts (solenoid armature, spool, spring)
• Override acts upon spool directly --- positive feedback
• Operates with vacuum, pressure or dual supplies
• Generally faster response time to shift valve, especially in non-rubber packed valves.
DISADVANTAGES:
• Requires low shift force mechanism --- rules out friction seals/dynamic o-rings as valve designs
• Larger solenoid required versus solenoid air pilot typically requires more electricity (wattage)
42
Valves
Solenoid
Operators
Solenoids
Armature
Coil ---Windings of
Current
Copper Wire
Electromagnet
With current supplied to the coil, an electromagnet is created. A laminate iron T armature is drawn to the electromagnet. It is this force that shifts the valve mechanism. An electromagnet takes more energy to create the magnetic force. Once created, less energy is required to maintain the circuit once the armature has been drawn completely to the electromagnet.
(Similar to the “flywheel concept – it takes more energy to get the flywheel moving than it does to maintain its motion.
Inrush* ----current required to create the electromagnet
Holding* ---- current required to maintain the electromagnet * Peculiar to are smaller than DC coils. AC
AC coils typicallyAC voltage only! coils typically generate more force per winding --but they get warm in doing so. (135oF is about maximum) 43
Valves
Construction
Solenoid/Air Pilot
Solenoid/Air Pilot
Main Valve
14
4 2
12
5 1 3
NOTE: Internal passage connects supply to the solenoid/pilot section; a minimum pressure is required to shift the main valve.
ADVANTAGES:
• Main valve shifted with supply air pressure --- typically more shifting force available than with a direct acting solenoid: required by friction seals and various other valve designs
• Smaller solenoid (less electrical power required) -- small three way valve, not much flow required
• May be faster ---depending on supply pressure and net shifting force --- than direct acting valves of similar size.
DISADVANTAGES:
Not faster as a general rule.
• Valve shifting force is dependent upon supply pressure --may require external supply
• Requires external pilot supply to become multi purpose
• Solenoid pilot valve has light shifting force with very small air passageways --- susceptible to sticking and failure
(some designs/manufacturers)
• Manual override acts upon pilot section only, not the main valve • More parts
44
Valves
Construction
Poppet Type --- Mechanical/Solenoid/Pilot
Position
1
EXHAUST
CYLINDER
SUPPLY
Flow paths when “B” pilot is pressurized or in command
Crossover
EXHAUST
CYLINDER
SUPPLY
Position 2
EXHAUST
CYLINDER
SUPPLY
Flow paths when “A” pilot is pressurized or in command
45
Valves
Construction
Spoppet Type --- Solenoid Air Pilot
CYL
Position
1
EXH
CYL
IN
EXH
Flow paths when “B” pilot is pressurized or in command Crossover
CYL
EXH
Position 2
CYL
IN
CYL
CYL
EXH
EXH
IN
EXH
Flow paths when “A” pilot is pressurized or in command 46
Valves
Construction
Spool and Sleeve Type --- Direct
A
B
Solenoid/Pilot (2)
(4)
(12) B
A
EA
(5)
P
(1)
E
(3)
B
(14)
Flow paths when “B” pilot is pressurized or in command A
B
(2)
(4)
(12) B
A
E
(3)
B
P
(1)
(14)
EA
(5)
Mid-Position, all ports blocked – closed
A
Bcrossover
(2)
(4)
(12) B
A (14)
EB
(3)
P
(1)
EA
(5)
Flow paths when “A” pilot is pressurized or in command
47
Valves
(2) (4)
(14)
(12)
(3) (1) (5)
P
“12” condition with spring in control
48
Valves
(2) (4)
(14)
(12)
(3) (1) (5)
P
“14” condition with solenoid energized
49
Valves
Basic Information
When selecting a valve ……
What type of valve is best for this application? Is the circuit design as safe and simple as possible?
What would happen if the lights went out --- will the valve default to a safe condition? 50
Valves
Function
14
12
2 position, 5 ported,
4 way, Single Solenoid
Air Pilot Actuated,
Spring Return
2 4
31 5
14
12
2 4
31 5
2 position, 5 ported,
4 way, Double Solenoid
Air Pilot Actuated,
Detented
51
Valves
Function
14
12
2 4
31 5
14
12
2 4
31 5
3 position, 5 ported,
4 way, Double Solenoid
Air Pilot Actuated,
Spring Centered,
5 Function
3 position, 5 ported,
4 way, Single Solenoid
Air Pilot Actuated,
Spring Centered,
6 Function
14
12
2 4
31 5
3 position, 5 ported,
4 way, Single Solenoid
Air Pilot Actuated,
Spring Centered,
7 Function
52
Valves
Summary
A.N.S.I. SYMBOLS
SOLENOID / AIR PILOT
SOLENOID
14
12
12
2 4
12
2 4
3 1 5
TWO
AIR PILOT
14
3 1 5
14
2 4
POSITION
VALVES
12
14
3 1 5
12
14
2 4
2 4
3 1 5
TWO
12
3 1 5
14
2 4
POSITION
3 1 5
VALVES
12
THREE
14
2
4
14
12
2
14
12
2 4
4
POSITION
3 1 5
VALVES
3 1 5
14
12
2 4
THREE
3 1 5
14
12
12
14
2 4
2
4
3 1 5
3 1 5
POSITION
3 1 5
VALVES
THREE
12
14
2
4
14
12
2 4
14
12
2
4
POSITION
VALVES
3 1 5
3 1 5
3 1 5
The circuit requirements determine the valve’s function. Knowing when to use each configuration is the responsibility of the designer and no one else. An educated choice is the first step towards safety, economy, and reliability.
53
Valves
Conclusion
REVIEW
Symbols
Valves
Flow Paths
2 Way
3 Way
4 Way 4 Ported
4 Way 5 Ported
Detent
3 Position
Solenoid
Mechanical
Air Pilot
Cylinders
Single Acting
Double Acting
Calculations
Area
Force
Circles
Needle Valves
Flow Controls
Inertia
54
Valves
More Symbols
55
Valves
More Symbols
56
Valves
NOTES
57 