Hydraulics, advanced level (textbook)

Hydraulics, Advanced Level (Textbook) Learning System for Automation and Communications 094015 Hydraulics Workbook Advanced Level TP502 • Festo Didactic Authorised applications and liability The Learn[.]

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Learning System for Automation and Communications

Hydraulics

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Authorised applications and liability

The Learning System for Automation and Communication has been de-veloped and prepared exclusively for training in the field of automationand communication The training organization and / or trainee shall en-sure that the safety precautions described in the accompanying Techni-cal documentation are fully observed.

Festo Didactic hereby excludes any liability for injury to trainees, to thetraining organization and / or to third parties occurring as a result of theuse or application of the station outside of a pure training situation, un-less caused by premeditation or gross negligence on the part of FestoDidactic.

Order no.: 094015

Description: TEACHW HYDRAUL.

Designation: D.S502-C-GBEdition: 06/1999

Layout: 14.06.1999, OCKER Ingenieurbüro

Graphics: OCKER Ingenieurbüro

Author: Th Ocker

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Preface

Festo Didactic’s Learning System for Automation and Communicationsis designed to meet a number of different training and vocational re-quirements The Festo Training Packages are structured accordingly:

Basic Packages provide fundamental knowledge of a wide range oftechnologies.

Technology Packages deal with important areas of open-loop andclosed-loop control technology.

Function Packages explain the basic functions of automation sy-stems.

Application Packages provide basic and further training closely orien-ted to everyday industrial practice.

Technology Packages deal with the technologies of pneumatics, elec-tropneumatics, programmable logic controllers, automation with PCs,hydraulics, electrohydraulics, proportional hydraulics and applicationtechnology (handling).

Fig 1:

Hydraulics 2000 –i.e mobile workstationMounting frame

Profile plateU = 230V~

p = 6 MPa

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The modular structure of the Learning System permits applications to beassembled which go beyond the scope of the individual packages It ispossible, for example, to use PLCs to control pneumatic, hydraulic andelectrical actuators.

All training packages have an identical structure:

Hardware

Courseware

Software

Courses

The hardware consists of industrial components and installations,adapted for didactic purposes.

The courseware is matched methodologically and didactically to thetraining hardware The courseware comprises:

Textbooks (with exercises and examples)

Workbooks (with practical exercises, explanatory notes, solutions anddata sheets)

OHP transparencies and videos (to bring teaching to life)

Teaching and learning media are available in several languages Theyhave been designed for use in classroom teaching but can also be usedfor self-study purposes.

In the software field, computer-based training programs and program-ming software for programmable logic controllers are available.

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Latest information about the technology package TP502.

New in Hydraulic 2000:

Industrial components on the profile plate.

Exercises with exercise sheets and solutions, leading questions.

Fostering of key qualifications:

Technical competence, personal competence and social competenceform professional competence.

Training of team skills, willingness to co-operate, willingness to learn,independence and organisational skills.

Aim – Professional competence

Content

Part A Course Exercises

Part B Fundamentals Reference to the text book

Part C Solutions Function diagrams, circuits, descriptions ofsolutions and quipment lists

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Table of contents

Introduction 9

Notes on safety 11

Notes on operation 11

Standard method of representation used in circuit diagrams 12

Technical notes 13

Training contents of “Hydraulics, Advanced Level” TP502 16

Hydraulic equipment set 18

Component/exercise table for TP502 22

Section A – Course

Exercise 1: Hose-reel drive system for tanker truck

Hydraulic motor A-3

Exercise 2: Table feed for a rough-grinding machine

Bypass with 2-way flow control valve A-7

Exercise 3: Lifting device with two cylinders

Flow divider A-11

Exercise 4: Rapid-traverse feed device for a drilling machine

Rapid-traverse feed circuit A-15

Exercise 5: Control system for a scrap press

Differential circuit A-21

Exercise 6: Clamping a gearbox casing

Accumulator A-27

Exercise 7: Plastic injection-moulding machine

Dual pressure circuit A-31

Exercise 8: Pipe-bending machine

Rectifier circuit A-35

Exercise 9: Single-column press

Flow control valves in inlet and outlet lines A-39Exercise 10: Machining centre

Sequence control with two cylinders A-45

Exercise 11: Magnetic crane

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Exercise 12: Folding machine

Pressure regulator A-53

Exercise 13: Earth drill

Rapid-traverse circuit with accumulator A-59Exercise 14: Machining centre

Electrical sequence control A-65

Section B – Fundamentals

Section C – Solutions

Solution 1: Hose-reel drive system for tanker truck C-3Solution 2: Table feed for a rough-grinding machine C-7

Solution 3: Lifting device with two cylinders C-13

Solution 4: Rapid-traverse feed device for a drilling machine C-17

Solution 5: Control system for a scrap press C-21

Solution 6: Clamping a gearbox casing C-27

Solution 7: Plastic injection-moulding machine C-31

Solution 8: Pipe-bending machine C-35

Solution 9: Single-column press C-39

Solution 10: Machining centre C-43

Solution 11: Magnetic crane C-47

Solution 12: Folding machine C-51

Solution 13: Earth drill C-57

Solution 14: Machining centre C-63

Section D – Appendix

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Introduction

This workbook forms part of Festo Didactic’s Learning System forAutomation and Communications The Technology Package “Hydrau-lics”, TP500, is designed to provide an introduction to the fundamentalsof hydraulic control technology This package comprises a basic leveland an advanced level The basic level package TP501 teaches basicknowledge of hydraulic control technology, while the advance levelpackage TP502 builds on this.

The basic level hydraulic exercises are designed to be carried out withmanual actuation It is, however, also possible to use electrical actua-tion The hydraulic components have been designed to provide the fol-lowing:

Easy handling

Secure mounting

Environmentally-friendly coupling system

Compact component dimensions

Authentic measuring methods

We recommend the following for the practical execution of the exer-cises:

Hydraulic components: Equipment set TP501 and TP502

One hydraulic power pack

A number of hose lines

A profile plate or a suitable laboratory trolley

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This workbook provides knowledge of the physical interrelationships andthe most important basic circuits in hydraulics The exercises deal withthe following:

Plotting of characteristics for individual components

Comparison of the use of different components

Assembly of various basic circuits

Use of basic hydraulics equations

The following technical equipment is required for safe operation of thecomponents:

A hydraulic power pack providing an operating pressure of 60 barand a flow rate of 2 l/min

An electrical power supply of 230V AC for the hydraulic power pack

A power supply unit with an output of 24V DC for solenoid-actuatedvalves

A Festo Didactic profile plate for mounting the components

The theoretical background is described in the “Hydraulics Basic Level”textbook TP501 Technical descriptions of the components used aregiven in the data sheets in Part D of this workbook.

Festo Didactic offers the following further training material for hydraulics:

Magnetic symbols

Hydraulics slide rule

Set of OHP transparencies

Transparent models

Interactive video

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Notes on safety

Observe the following in the interests of your own safety:

Exercise care when switching on the hydraulic power pack Cylindersmay advance unexpectedly!

Do not exceed the maximum permissible operating pressure (seedata sheets).

Observe all general safety instructions (DIN 58126 and VDE 100).

Notes on operation

Always work in the following sequence when assembling a hydrauliccircuit.

1 The hydraulic power pack and electrical power supply must beswitched off during the assembly of the circuit.

2 All components must be securely fitted to the profile plate, i.e se-curely snap-fitted or bolted down.

3 Check that all return lines are connected and all hose lines are se-curely fitted.

4 Switch on the electrical power supply first and then the hydraulicpower pack.

5 Before dismantling the circuit, ensure that pressure in hydraulic com-ponents has been released:

Couplings must be connected and disconnected only underzero pressure!

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Standard method of representation used in circuitdiagrams

The hydraulic circuit diagrams are based on the following rules:

Clear representation avoiding crossovers as far as possible

Symbols conforming to DIN/ISO 1219 Part 1

Circuit diagrams with several loads are divided into control chains

Identification of components in accordance with DIN/ISO 1219 Part 2:

• Each control chain is assigned an ordinal number 1xx, 2xx, etc.

• The hydraulic power pack is control chain 0xx.

• Identification of components by letters:A – Power componentB – Electrical sensorsP – PumpS – Signal generatorV – ValveZ – Other component

• The complete code for a component consists of– a digit for the control chain,

– a letter for the component,

– a digit for the consecutive numbering of components in accor-dance with the direction of flow in the control chain.

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Technical notes

Observe the following in order to ensure safe operation.

The hydraulic power pack PN 152962 incorporates an adjustablepressure relief valve In the interests of safety, the pressure is limitedto approx 60 bar (6 MPa).

The maximum permissible pressure for all hydraulic components is120 bar (12 MPa).

The operating pressure should not exceed 60 bar (6 MPa).

In the case of double-acting cylinders, the pressure intensificationeffect may produce an increased pressure proportional to the arearatio of the cylinder With an area ratio of 1:1.7 and an operatingpressure of 60 bar (6 MPa), this increased pressure may be over100 bar (10 MPa)!

If connections are detached under pressure, the non-return valve inthe coupling may cause pressure to become trapped in the valve orother component concerned The pressure relieving devicePN 152971 can be used to release this pressure Exception: This isnot possible in the case of hose lines and non-return valves.

All valves, other components and hose lines are fitted with self-closing quick-release couplings This prevents the accidental spillageof hydraulic fluid In the interests of simplicity, these couplings are notshown in circuit diagrams.

Throttle valveHoseShut-off valve

Fig 2:

Pressure intensification

Fig 3:

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It is frequently necessary when assembling a control circuit to modifythe given circuit diagram Within the scope of the equipment set inthis Training Package, the following alternative solutions are possible:– Plugs can be used to change the function of directional control

valves (Figs 4 and 5).

– Directional control valves with different normal positions can beused (Fig 6).

– Solenoid-actuated valves can be used in place of hand levervalves (Fig 7).

2/2-way valve3/2-way valve

4/2-way valve4/2-way valve

Circuit diagramPractical assembly

Fig 4:Circuit diagram

Fig 5:Practical assembly

Fig 6:Directional control valveswith variousnormal positions

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Flow rate sensor

The flow rate sensor consists of:

A hydraulic motor, which converts the flow rate q into a rotaryspeed n.

A tachogenerator, which produces a voltage V proportional to therotary speed n.

A universal display unit, which converts the flow rate q into l/min Theuniversal display should be set to sensor no 3 for this purpose.

qHydraulicmotornTacho-generatorVUniversal-displayqFig 8:

Block circuit diagram

Fig 9:

Circuit diagrams,hydraulic and electrical

Fig 10:

Connecting up theuniversal display

Battery operation

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Training contents of “Hydraulics,Advanced Level” TP502

Uses of valves and other components

Comparison of uses and functions of different valves and other com-ponents

Measurement of variables such as pressure, flow rate and time

Control of pressure and speed

Calculations of area ratios, forces, speed, travel time, flow rate andenergy consumption

Basic physical principles of hydraulics

Use of symbols in accordance with DIN/ISO 1219

Understanding and drafting of circuit diagrams

Drafting of displacement-step diagrams

Assembly and commissioning of control circuits, including fault- find-ing

Assessment of energy consumption

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List of training aims of exercises

ExerciseTraining aims

1Familiarisation with a hydraulic motor.Adjustment of direction and speed of rotation.2Familiarisation with a 2-way flow control valve.

Use of a circuit with bypass.

3Use of a flow divider for synchronous running of two cylinders.4Familiarisation with a rapid-traverse feed circuit.

5Familiarisation with a differential circuit.

6Use of a hydraulic accumulator as a pressure reservoir.7Familiarisation with a dual pressure circuit.

8Familiarisation with a rectifier circuit.

9Familiarisation with the use of 2-way flow control valves in inlet and outletlines Familiarisation with counter-holding.

10Familiarisation with a sequence control with two cylinders.Familiarisation with a pressure sequence circuit.

11Familiarisation with a safety circuit for a tractive load.

12Familiarisation with the function and use of a pressure regulator.13Use of a hydraulic accumulator for a rapid-traverse circuit.14Familiarisation with a solenoid-actuated sequence control.

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Hydraulic equipment set

DescriptionOrder No.Qty.

Pressure gauge1528413

Throttle valve1528421

One-way flow control valve1528431

Shut-off valve1528441

Non-return valve, opening pressure 1 bar1528451

Branch tee1528477

Pressure relief valve1528481

Pressure relief valve, piloted1528491

Pressure regulator1528501

Flow control valve1528511

Non-return valve, piloted1528521

Double-acting cylinder1528571

Hydraulic motor1528581

Diaphragm accumulator1528591

Weight, 9 kg1529721

4/2-way hand lever valve1529741

4/3-way hand lever valve with bypass mid-position1529771

Mounting kit for cylinder1207781

Branch tee1528474

Cylinder1528571

Flow-dividing valve1529671

Equipment set for“Hydraulics, Basic Level”TP501, PN 080246

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Relay, 3-fold0110871

Signal input unit, electrical0110881

Stop-watch1515041

4/2-way solenoid valve1528531

4/3-way solenoid valve closed in mid-position1528541

Limit switch, electrical1529061

Universal display1529881

Pressure sensor1529891

Flow sensor1529911

Cable set0303321

Profile plate, large0303501

Power supply unit1515031

Hose line, 600 mm15296012

Hydraulic power pack1529621

Hose line, 1000 mm152704

Pressure relieving device1529711

Protective cover1529731

Additional equipment

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DescriptionSymbol

Mounting kit for cylinder

One-way flow control valve

Branch tee

Pressure relief valve

Cylinder

Flow-dividing valve

Shut-off valve

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DescriptionSymbol

4/3-way hand lever valve closed in mid-position

4/3-way hand lever valve with relieving mid-position

2/2-way stem-actuated valve

Symbols for

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Component/exercise table for TP502

Exercises

Description1234567891011121314

Mounting kit111

Pressure gauge12111321344412

Throttle valve11

Branch tee254446483736

3-way pressure-reducing valve1

2-way flow control valve11111111

Non-return valve, piloted11

Cylinder, double-acting211111121212

Hydraulic motor11

Diaphragm accumulator11

Flow-dividing valve1

Weight1111

4/2-way hand lever valve11111

4/3-way hand lever v closed in mid-position1

4/3-way hand lev v with relieving mid-position111

4/3-way hand lev v with bypass mid-position11111

2/2-way stem-actuated valve111

Hydraulic power pack11111111111111

Hose line, 600 mm265666774105979

Hose line, 1000 mm22422422434223

Hydraulic motor with flow sensor11

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Electrical equipment for exercise 14

Relay, 3-fold0110872

Signal input unit1622421

4/2-way solenoid valve1528531

4/3-way solenoid valve closed in mid position1528541

Limit switch1529063

The exercises appear in section A, with solutions to these in section C.The methodological structure is the same for all exercises.

The exercises in section A are structured as follows:

Subject Title Training aim(s) Problem definition Exercise Positional sketch

A worksheet then follows for use in carrying out the exercise.

The solutions in section C contain the following:

Hydraulic circuit diagram

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A-1

Section A – Course

Exercise 1: Hose-reel drive system for tanker truck

Hydraulic motor A-3

Exercise 2: Table feed for a rough-grinding machine

Bypass with 2-way flow control valve A-7

Exercise 3: Lifting device with two cylinders

Flow divider A-11

Exercise 4: Rapid-traverse feed device for a drilling machine

Rapid-traverse feed circuit A-15

Exercise 5: Control system for a scrap press

Differential circuit A-21

Exercise 6: Clamping a gearbox casing

Accumulator A-27

Exercise 7: Plastic injection-moulding machine

Dual pressure circuit A-31

Exercise 8: Pipe-bending machine

Rectifier circuit A-35

Exercise 9: Single-column press

Flow control valves in inlet and outlet lines A-39Exercise 10: Machining centre

Sequence control with two cylinders A-45

Exercise 11: Magnetic crane

Tractive load A-49

Exercise 12: Folding machine

Pressure regulator A-53

Exercise 13: Earth drill

Rapid-traverse circuit with accumulator A-59Exercise 14: Machining centre

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A-3

Exercise 1

Hydraulics

Hose-reel drive system for tanker truck

Familiarisation with a hydraulic motor.

Adjustment of direction and speed of rotation.

Drawing the circuit diagram.

Practical assembly of the circuit.

Setting of various rotary speeds for hydraulic motor.

Recording the time taken for 20 revolutions of the motor in eachcase.

Plotting the measured values.

Drawing conclusions.

SubjectTitle

Training aims

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A-4

Exercise 1

The hose reel of a heating-oil tanker truck is driven by a hydraulic motor.This must allow the hose to be unwound, the reel to be stopped for alengthy period, and the hose to be wound up again A 4/3-way valve isto be used to obtain these functions The speed must be adjustable bymeans of a throttle valve.

Exercise

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A-6

Exercise 1

What happens with the directional control valve in different switchingpositions?

What happens with different throttle valve settings?

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A-7

Exercise 2

Hydraulics

Table feed for a rough-grinding machine

Familiarisation with a 2-way flow control valve.

Use of a circuit with a bypass.

Pressure and flow-rate measurements.

Determination of power balance.

SubjectTitle

Training aims

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A-8

Exercise 2

The table feed of a grinding machine must be adjustable Slight varia-tions in the feed speed as a result of changes in working pressure arepermissible The table is driven by a constant-displacement pump Anenergy-saving circuit with a 2-way flow control valve is to be developedfor this.

The power balance must be determined and compared firstly for a cir-cuit in which the 2-way flow control valve is fitted in the bypass and sec-ondly for a circuit in which this valve is fitted directly in the supply line tothe directional control valve In both cases, the flow rate at the hydraulicmotor should be set to 1 l/min., with a counter-pressure of 20 bar.

Exercise

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A-9Exercise 2WORKSHEETPressureupstream of FCV(bar)Pressuredownstream of FCV(bar)Flow rate at FCV(l/min)FCV in inletFCV in bypass

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A-10

Exercise 2

Power balance with flow control valve in inlet line

Drive power of hydraulic pumpPP =pP⋅qPPP = Power lossPV =

Power balance with flow control valve in bypass

Drive power of hydraulic pumpPP =

Power loss

PV =

Calculation of power loss via bypass

PV =pV⋅qV

PV =

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A-11

Exercise 3

Hydraulics

Lifting device with two cylinders

Flow divider for synchronous running of two cylinders.

Studying the use of a flow divider to obtain synchronous running.

SubjectTitle

Training aims

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A-12

Exercise 3

A lifting device for heavy loads in equipped with two hydraulic cylinders.In order for this to operate correctly, the two piston rods connected tothe table must both advance at the same speed, even when subjectedto a one-sided load A circuit must be developed using a flow divider.Two non-return valves are required to guide the return flow of hydraulicfluid past the flow divider A weight is placed on one cylinder to demon-strate a one-sided load.

Exercise

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A-13

Exercise 3

WORKSHEET

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A-14

Exercise 3

Which cylinder advances first when the circuit has no flow divider?

What is the effect of fitting the flow divider when the cylinders are sub-jected to unequal loads?

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A-15

Exercise 4

Hydraulics

Rapid-traverse feed device for a drilling machine

Familiarisation with a rapid-traverse feed circuit.

Plotting a displacement-step diagram.

Adjusting the feed speed by means of the 2-way flow control valve.

Measurement of advance-stroke times.

Calculation of advance-stroke speeds.

SubjectTitle

Training aims

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A-16

Exercise 4

Machine tools are often fitted with so-called rapid-traverse feed circuits.The drilling machine shown here is required to advance to the workpieceat a rapid-traverse speed and then drill the workpiece using a lower feedspeed The rapid-traverse speed allows shorter production times to beachieved The feed speed must be adjustable to allow it to be matchedto the material and drill-bit diameter in question.

The solution of this exercise requires the development of a circuit with a4/2-way hand lever valve The switchover from rapid traverse to feedspeed is initiated by a 2/2-way stem-actuated valve, in turn actuated viaa cam attached to the cylinder The feed speed must be adjustable bymeans of a 2-way flow control valve A bypass must be provided for theflow control valve via a non-return valve to allow the return stroke to beexecuted at maximum speed.

Exercise

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