Do You Know How To Control Pneumatic System ?

The Answer Is By Using Directional Valve

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Introduction

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The function of valve is to control the pressure or flow rate of pressure media. Depending on design, this can be divided into the following categories : i. Directional control valve Input or signalling element Processing element Control element ii. Non-return valves iii. Flow control valves iv. Pressure control valves v. Shut-off valves

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Introduction

The directional control valve controls the passage of air signals by generating, cancelling or redirecting signal.The valve is described by : i. Number of ports or opening (way)

Example : 2- way, 3-way, 4- way, etc.ii. Number of position

Example : 2 positions, 3 positions, etc.

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Directional Control Valveiii. Methods of actuation of the valve : Manually actuated Mechanical actuated Pneumatically actuated Electrical actuated Combined actuated

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iv. Methods of return actuation : . Spring return, air return, etc

1. The valve switching position is shown by square. . 2. The number of square corresponds to the number of switching positions. 3. Line indicate the flow path, arrows indicate the direction of flow. 4. Closed ports are shown by two lines drawn at right angles to one another. 5. The connecting lines for supply and exhaust air are drawn outside the square.7

Pneumatic revision (cont..)y Information about the type of valve can be established from the following features:Number of ports y Number of switching positions y Port numberingy

y The following applies to the numbering of the ports:Air supply port y Exhaust ports y Working or outlet portsy

1 3,5 2,4

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2/2 way valve, normally open position.

3/2 way valve, normally closed position.

VALVE DESCRIPTION 1 VALVE DESCRIPTION 2

4/2 way valve flow from 1 to 2 & from 4 to 3

5/2 way valveflow from 1 to 2 & from 4 to 5 VALVE DESCRIPTION

5/3 way valve mid position closed

Poppet Valve 2/2y The Poppet valve is a simple and

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effective design used mainly in 2/2 and 3/2 functions y It has good sealing characteristics and can often be the choice for a supply shut off valve y A poppet seal has a butt action against a raised edged aperture y Illustrated is a 2/2 air operated poppet valve

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Poppet Valve 2/2y The Poppet valve is a simple and

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effective design used mainly in 2/2 and 3/2 functions y It has good sealing characteristics and can often be the choice for a supply shut off valve y A poppet seal has a butt action against a raised edged aperture y Illustrated is a 2/2 air operated poppet valve

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Poppet Valve 3/2y Miniature 3/2 valve used for y

y y

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generating signals The poppet seal will give long life (not subjected to sliding friction) Supply to port 1 assists the spring to hold the poppet shut Outlet port 2 is connected through the plunger to a plain exhaust port When operated exhaust path sealed and poppet opened (flow 1 to 2)

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Poppet Valve 3/2y Miniature 3/2 valve used for y

y y

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generating signals The poppet seal will give long life (not subjected to sliding friction) Supply to port 1 assists the spring to hold the poppet shut Outlet port 2 is connected through the plunger to a plain exhaust port When operated exhaust path sealed and poppet opened (flow 1 to 2)

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Poppet Valve 3/2y Miniature 3/2 valve used for y

y y

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generating signals The poppet seal will give long life (not subjected to sliding friction) Supply to port 1 assists the spring to hold the poppet shut Outlet port 2 is connected through the plunger to a plain exhaust port When operated exhaust path sealed and poppet opened (flow 1 to 2)

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Spool Valve (static seals)y This 3/2 valve has a plain spool sliding within static seals y The O Ring seals are held in carriers fixed in the valve bore and

positioned by spacers (not shown) y The larger O Rings seal the valve bore with the carriers y The smaller O Rings seal the carriers with the spool

212 3 2 10 1

12 3 1

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Spool Valve (static seals)y This 3/2 valve has a plain spool sliding within static seals y The O Ring seals are held in carriers fixed in the valve bore and

positioned by spacers (not shown) y The larger O Rings seal the valve bore with the carriers y The smaller O Rings seal the carriers with the spool

212 3 2 10 1

12 3 1

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Actuator Control (3/2 valve)y A 3 port valve provides the

inlet, outlet and exhaust path and is the normal choice for control of a single acting cylinder y In the normal position produced by the spring, the valve is closed y In the operated position produced by the push button the valve is open y The push button must be held down for as long as the cylinder is outstroked

Actuator Control (3/2 valve)y A 3 port valve provides the

inlet, outlet and exhaust path and is the normal choice for control of a single acting cylinder y In the normal position produced by the spring, the valve is closed y In the operated position produced by the push button the valve is open y The push button must be held down for as long as the cylinder is outstroked

Spool Valve (dynamic seals)y This 5/2 valve has a spool fitted with disc seals y The seals move with the spool therefore they are called dynamic y Normal position: port 1 is joined to 4 and 2 is joined to 3 y Operated position: port 1 is joined to 2 and 4 is joined to 5

4 14 1 5

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14 5 4 1 2 3

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Spool Valve (dynamic seals)y This 5/2 valve has a spool fitted with disc seals y The seals move with the spool therefore they are called dynamic y Normal position: port 1 is joined to 4 and 2 is joined to 3 y Operated position: port 1 is joined to 2 and 4 is joined to 5

4 14 1 5

2 12

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14 5 4 1 2 3

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Actuator Control (5/2 valve)y A five port valve provides an

inlet port 1 that is switched between two outlet ports 2 and 4 each with an exhaust port 3 & 5 y In the normal position produced by the spring 1 is connected to 2 with 4 to exhaust 5 y In the operated position produced by pushing the button port 1 is connected to 4 with 2 to exhaust 3

Actuator Control (5/2 valve)y A five port valve provides an

inlet port 1 that is switched between two outlet ports 2 and 4 each with an exhaust port 3 & 5 y In the normal position produced by the spring 1 is connected to 2 with 4 to exhaust 5 y In the operated position produced by pushing the button port 1 is connected to 4 with 2 to exhaust 3

MANUAL

MECHANICAL

PNEUMATIC

Double pneumatic actuation

ELECTRO-PNEUMATIC

COMBINED

5/3 way valveTo derive double acting cylinder 2 rods, with the possibility of stopping the cylinder in any positions

5/3 way valveTo derive double acting cylinder 2 rods, with the possibility of stopping the cylinder in any positions

5/3 way valveTo derive double acting cylinder 2 rods, with the possibility of stopping the cylinder in any positions