2010B5A4498G_pnuematics

PNUEMATICS AND AUTOMATION

KARANDIKAR ADITYA RAVINDRA 2010B5A4498G

BATCH 6

i

INDEX:

Sr. No. TITLE Page No.

1 INTRODUCTION 1

2 EXERCISE 7A 2

3 EXERCISE 7B 5

4 EXERCISE 7C 8

5 EXERCISE 7D 12

6 EXERCISE 8A 16

7 EXERCISE 8B 18

8 EXERCISE 8C 22

1

INTRODUCTION:

PNEUMATICS:

Pneumatics is a type of power transmission that uses gas (air in our case) to create movements. It is

similar to hydraulics which uses fluids like oil and water instead of gas. Pneumatics has various

applications and is considered to be very economical. For example

1. Air brakes on buses and trucks

2. Air brakes on train

3. Door opening and closing in buses

4. There are various advantages of Pneumatics

5. The medium used is compressed air which is inexpensive and we can get it easily

6. The medium which we use is non-polluting so this can be used in medicine and other areas

where clean environment is required.

7. Pneumatics components are very reliable. They have long life and less maintenance as the

medium which we use is compressed air so the cylinders being corroded is less.

COMPRESSED AIR: Compressed air acts like power transmitter which changes to mechanical

movements of the piston cylinder. Here we keep the pressure of the compressed air between 6-

8bars. The reason for using compressed air is that it is freely available and in any circumstances we

will not have shortage of it. Secondly the damage done to the equipment is minimal as air is

compressible so equipment is less subjected to shock as compressed air absorbs the shock.

2

EXERCISE 7A

Aim: To identify different pneumatic components and understand their working.

Components:

FRL unit: Filter regulator lubricator. The sign of FRL unit is given below.

3/2 push button

5/2 push button

AND gate (dual pressure valve)

OR gate

5/2 way single pilot valve

5/2 way double pilot valve

3/2 roller lever valve

Time delay valve

One way flow control valve

Pressure sequence valve


Single acting cylinder

Double acting cylinder

Procedure:

1. Identify the above components mounted on the training kit.

2. Identify the symbols of the components.

3. Know the working of each component by connecting it in the circuit.

3

4. Know the hierarchy of the components in pneumatic system structure and the signal flow.

Elements of Pneumatic automation system:

Command execution Working elements

Cylinders

Motors

Optical indicators

Signal output Control elements

Directional control valves

Signal processing Processing elements

Directional control valves

Shuttle valves

Dual pressure valves Pressure sequence

valves sequencers

Signal input Input elements

4

Push button directional

Control valves

Roller lever valves

Proximity switches

Air barriers

Energy supply Energy supply elements

Compressor

Pneumatic reservoir

Pressure regulating valve

Service unit

5

EXERCISE 7B

Aim: To construct the following circuits using different components on the basin pneumatic kit

To control a single acting cylinder through a 3/2 push button and 3/2 way valve

To control a double acting cylinder through a push button and 5/2 way spring return valve

To control a double acting cylinder through two push buttons and 5/2 pneumatic valve using

separate push buttons for the extension and retraction of the cylinder

Components:

Single acting cylinder


3/2 push button

5/2 way valve

5/2 way double valve

Procedure:

Regulate the circuit pressure to 4 bar

Regulate the circuit to 4 bar

Connect the different components according to the circuit diagram

Test the working of the circuit.

Observation:

When the 3/2 push button is activated the air enters the 3/2 way valve and activates the valve. This

provides the compressed air to enter the front end of the single acting cylinder causing its extension.

6

Here when the 3/2 push button in pressed it activates the 5/2 way single pilot valve by which air

passes in the front end of the double acting cylinder thereby causing extension of the cylinder. On

releasing of the button the 5/2 valve comes to the initial position and thereby the cylinder retracts.

7

Here when the 3/2 switch is pressed then the 5/2 way valve is activated which by allows air to pass

through the front end of the double acting cylinder. This stays until another 3/2 is pressed which

ensures that the 5/2 valve is activated and it retracts the cylinder to the original position

.

8

EXERCISE 7C

Aim: To construct the following components on the basic pneumatic kit

Actuation of return stroke of a double acting cylinder by any of the two push buttons and sensing

with a roller sensor. Immediate forward by sensing the rear position of cylinder.

Actuation of a double acting from the two push buttons pressed simultaneous ly. The actuation must

be possible by getting a confirmation of full extension.

Continuous reciprocation of a double acting cylinder on switching a 3/2 way push button.

Components:


3/2 push buttons




Shuttle valve

Dual pressure valve

Quick exhaust valve

Procedure:

Regulate the circuit pressure to 4 bar

Regulate the circuit to 4 bar

Connect the different components according to the circuit diagram

Test the working of the circuit.

9

Observation:

As the push buttons are connected by OR gate activation by any one of them will enable the

compresses air to activate the 5/2 way valve. But the activation is only possible when the roller

sensor is pressed. Once the roller sensor is pressed it allows the air flow into the first end of the

double acting cylinder which helps is extension of the cylinder and when it extends the cylinder

presses the second roller. When the second roller is pressed it allows air flow into the 5/2 way valve

and the cylinder retracts. This again

presses the first roller sensor and again extension takes place.

Here we use AND gate so the two 3/2 push buttons should be pressed simultaneously by which the

air activates the AND gate and allows to flow. Air passes through 5/2 way valve which activates the

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double acting cylinder when it is completely retracted and presses to roller. Once the roller is

pressed the cylinder extends and then it presses the roller sensor. Once the second roller sensor is

pressed air flows through the 5/2 way valve which helps in retraction of the cylinder.

Here when the 3/2 button is pressed , the compressed air activates 5/2 valve which allows the air to

enter the front end of the cylinder thereby causing extension. Here the two rolling sensors sense the

extension and retraction there by providing continuous reciprocating motion. This continuous unless

the push button is pressed again.

12

EXERCISE 7D

Aim: To construct the following circuits using different components on the basic Pneumatic kit.

Actuation of double acting cylinder form two push buttons pressed simultaneously and when

cylinder at its retracted position. The retraction is automatic when forward end position is

confirmed and preset pressure has been reached. Immediate retraction is possible if push button is

pressed.

Actuation of double acting cylinder through a push button when cylinder is at its retracted position.

Slow building of pressure when the cylinder is at its forward position is confirmed and preset

pressure of 4 bar has been reached and it is held with this

pressure for 5seconds. The restarting is possible 20s after the retracting position is reached.

Sequencing of two cylinders having sequence of A+B+B-A-, A+B+A-B etc.

Components:


3/2 push buttons




AND gate

Time delay valve


Pressure guage

13

Observations:

Here we actually check how much pressure the cylinder exerts after it’s extended. So to check that

we use a pressure sequence valve. The extension of the cylinder is sensed by roller and it. Generally

we connect the second end to the 5/2 valve but here we will instead connect to the pressure

sequence valve. We will preset the pressure to particular value and check the amount of pressure

building in the cylinder. The output of the pressure sequence valve is connected to the 5/2 way

valve. If the pressure build in the pressure sequence valve is equal to the pressure set in it then the

air activates the 5/2 valve and it retracts back.

14

In this we use a time delay valve. Here there is slight delay because of the presence of the time delay

valve because of the presence of flow control valve. The air activates the 5/2 way valve by which air

passes through the front end of the double acting cylinder which is at the initial position. When the

air passes it extends and then presses the roller sensor. This causes air to pass through the pressure

sensor and time delay. When enough pressure is met then the air activates the 5/2 way valve and

retraction takes place.

This circuit makes the following sequence. Here both the cylinders are initially in the default posi tion

of being retracted. When the push button is pressed this activates the 5/2 way valve of the first

15

circuit and which extends the first cylinder. Because of this A+ becomes true which results in the

extension of the second cylinder now B+ becomes true resulting in the retraction of the cylinder 1

and this process continues unless the push button is pressed.

16

EXERCISE 8A

Aim:

To identify different electro pneumatic components and understand their working.

To study the latching logic and obtain an electric circuit having a latch.

Components: We have the following components

5/2 single solenoid valve

5/2 double solenoid valve

Distribution and power supply units

Magnetic reed switches

Capacitive proximity sensor

Optical sensor

Inductive proximity

Relays

Procedure:

Identify the above components mounted on the training kit.

Know the working of each component by connecting it in the circuit

Understand the NO and NC.

Verifying the latching circuit by connecting the component according to the circuit diagram.

Observation:

Here we observe that electric voltage is the driver which activates the solenoid valves thereby

causing the actuators to produce motions

17

Power Sources: These provide power to the circuits. Generally it is 24V DC but we can have AC

sources also

Switches: They are basically used to complete the circuit or break it thereby causing the air flow and

activating valves. Some of the examples normally open or normally closed switches. There are three

types of switches namely magnetic reed switch, capacitive proximity switch and inductive proximity

switch.

Electro Pneumatic valves: These are same as the mechanical valves but consist of an

electromagnetic spool which magnetizes on the passage of current and allows the flow of air. There

are two types of valves which we will mainly use in this experiment, they are 5/2 double solenoid

valve and 5/2 single solenoid valve.

Observation: Here when we close the switch s1 current flows and the circuit is complete. Now since

the relay is activated in spite of us switching off s1 the current flows as the circuit is completed by

parallel connection of the relay. The buzzer is activated.

18

EXERCISE 8B

Aim: To form the following circuits using different components on the Electro- pneumatic kit.

Extension of a double acting cylinder on pressing a push button S1 and retraction of the cylinder

using a push button S2

Extension of a double acting cylinder on pressing a push button S1 AND S2 OR S3.

Immediate retraction on switching off the any of the switches.

Slow extension of a double acting cylinder on pressing a push button S1. Quick return of the cylinder

only after confirming the full extension.

Components:

5/2 single solenoid valve.


Distribution and power supply units.


Relays

Procedure:

Regulate the circuit pressure to 4 bar using the pressure switch.

Connect the different components according to the circuit diagram.

Observation:

Here when the switch s1 is pressed the electro- pneumatic valve gets activated and thereby passes

air in the front end of the cylinder and the cylinder extends. When the switch s2 is pressed the 5/2

electro- pneumatic valve is activated and it results in retraction

19

Here s1 and s2 are connected in AND logic where we use two switched so when these two switches

are simultaneously pressed the electro-pneumatic valve gets activated and passes air by which the

cylinder extends. Here s3 is connected in OR form and when only s3 is pressed the valve gets

activated and extends the cylinder.

21

When S1 is closed it results in activating the relay k1 and activating the solenoid which activates the

electro-pneumatic valve and air flows in the front end of the cylinder and extension takes place.

When switch s2 is pressed it activates the valve and the cylinder retracts back.

22

EXERCISE 8C

Aim: To construct the following circuits using different components on the electro pneumatic kit.

Extension of a double acting cylinder when a NO and NC sensors sense different aspects of an

object. Retraction on confirming the full extension using a capacitive sensor.

Use a push button to start oscillation of a double acting cylinder. It must be stopped by switching off

another button.

Obtain a sequential logic of two double acting cylinders having sequence A+B+B-A- with latching

incorporated in it.

Components:

5/2 single solenoid valve.


Distribution and power supply units.


Relays

Procedure:

Regulate the circuit pressure to 4 bar using the pressure switch.

Connect the different components according to the circuit diagram.

Observation:

When switch s1 is pressed relay k1 uses latching logic to activate the y1 and thereby it allows air to

pass through the cylinder and it extends the cylinder. When the cylinder reaches LS1 relay is

activated and the second part of the latching is switched on. Again Y2 is activated and retraction

stroke of the cylinder is completed.

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Once switch S1 is pressed, relay K1 is activated, causing LS1 and Ls2 to get activated. These two

optical sensor detect the position of the cylinder piston and cause it to oscillate till switch S2 is

pressed cutting off power supply to relay S2.

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The figure shows the situation after switch S1 activated relay K1. The piston in cylinder B is

retracting, which will activate Ls3. This in turn will cause Y1 to make cylinder A extend, LS2 will get

activated, causing Y3 to extend cylinder B and so on.

2010B5A4498G_pnuematics

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