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WorkbookTP 230
CD-ROM included
Festo Didactic
567258 EN
Fundamentals of vacuum technology
12
22
32
42
.2
.3
14
24
34
44
11
21
31
41
K1
14 2412 22
11 21
1
S1
K1 1M1
24 V 32
0 V
A1
A2
K1
S2
31
13
32
14
1
V2V1
2
33
2
1M131
1A1
2
311V4
1Z2
1V1
1Z1
1V2 1V3
1A2
Order No.: 567258
Edition: 10/2010
Authors: Ralph-Christoph Weber
Editor: Frank Ebel
Graphics: Ralph-Christoph Weber
Layout: 01/2011, Susanne Durz, Frank Ebel
© Festo Didactic GmbH & Co. KG, 73770 Denkendorf, Germany, 2011
Internet: www.festo-didactic.com
E-mail: [email protected]
The copying, distribution and utilization of this document as well as the communication of its contents to
others without expressed authorization is prohibited. Offenders will be held liable for the payment of
damages. All rights reserved, in particular the right to carry out patent, utility model or ornamental design
registration.
© Festo Didactic GmbH & Co. KG 567258 III
Contents
Use for intended purpose __________________________________________________________________ IV
Preface _________________________________________________________________________________ V
Introduction ____________________________________________________________________________ VII
Safety precautions and work instructions ____________________________________________________ VIII
Technology package for electro-pneumatics (TP 200) ____________________________________________X
Learning objectives for the advanced level (TP 230) _____________________________________________ XI
Allocation of learning objectives per exercise _________________________________________________ XII
Equipment set for the advanced level (TP 230) ________________________________________________ XIII
Allocation of equipment per exercise ________________________________________________________ XVI
Tools for the trainer _____________________________________________________________________ XVII
Structure of the exercises ________________________________________________________________ XVII
Component designations _________________________________________________________________ XVII
CD-ROM contents _______________________________________________________________________ XVIII
Exercises and solutions
Exercise 1: Generating vacuum _______________________________________________________________ 3
Exercise 2: Selecting suction cups for various workpieces _______________________________________ 11
Exercise 3: Maintaining vacuum when using more than one suction cup ____________________________ 21
Exercise 4: Monitoring partial vacuum _______________________________________________________ 29
Exercise 5: Reducing compressed air consumption in a vacuum system ____________________________ 37
Exercise 6: Controlled release of workpieces retained by a vacuum ________________________________ 43
Exercises and worksheets
Exercise 1: Generating vacuum _______________________________________________________________ 3
Exercise 2: Selecting suction cups for various workpieces _______________________________________ 11
Exercise 3: Maintaining vacuum when using more than one suction cup ____________________________ 21
Exercise 4: Monitoring partial vacuum _______________________________________________________ 29
Exercise 5: Reducing compressed air consumption in a vacuum system ____________________________ 37
Exercise 6: Controlled release of workpieces retained by a vacuum ________________________________ 43
Contents
IV © Festo Didactic GmbH & Co. KG 567258
Basic principles of vacuum technology
1 Introduction to vacuum technology __________________________________________________ I-3
1.1 Vacuum technology, basic terminology ________________________________________________ I-3
1.2 Vacuum ranges ___________________________________________________________________ I-5
2 Vacuum generation in handling technology ____________________________________________ I-7
2.1 Vacuum pumps ___________________________________________________________________ I-7
2.2 Displacement pump mode of operation _______________________________________________ I-7
2.3 Notes regarding pump selection ____________________________________________________ I-10
2.4 Ejectors ________________________________________________________________________ I-11
3 Vacuum components in handling technology _________________________________________ I-17
3.1 Valves _________________________________________________________________________ I-17
3.2 Vacuum gauges _________________________________________________________________ I-17
3.3 Vacuum reservoirs _______________________________________________________________ I-18
3.4 Suction cups ____________________________________________________________________ I-19
3.5 Bellows suction cups _____________________________________________________________ I-20
3.6 Suction cup selection _____________________________________________________________ I-21
3.7 Vacuum security valves ___________________________________________________________ I-23
© Festo Didactic GmbH & Co. KG 567258 V
Use for intended purpose
The training package for “Fundamentals of vacuum technology” may only be used:
• For its intended purpose in teaching and training applications
• When its safety functions are in flawless condition
The components included in the training package are designed in accordance with the latest technology, as
well as recognised safety rules. However, life and limb of the user and third parties may be endangered, and
the components may be impaired if they are used improperly.
The training system from Festo Didactic has been developed and manufactured exclusively for training and
vocational education in the field of automation technology. The respective training companies and/or
trainers must ensure that all trainees observe the safety precautions which are described in this workbook.
Festo Didactic hereby excludes any and all liability for damages suffered by trainees, the training company
and/or any third parties, which occur during use of the equipment set in situations which serve any purpose
other than training and/or vocational education, unless such damages have been caused by Festo Didactic
due to malicious intent or gross negligence.
VI © Festo Didactic GmbH & Co. KG 567258
© Festo Didactic GmbH & Co. KG 567258 VII
Preface
Festo Didactic’s learning system for automation technology is geared towards various educational
backgrounds and vocational requirements. The learning system is therefore broken down as follows:
• Technology oriented training packages
• Mechatronics and factory automation
• Process automation and control technology
• Robotino® – training and research with mobile robots
• Hybrid learning factories
The technology packages deal with various technologies including pneumatics, electropneumatics,
hydraulics, electrohydraulics, proportional hydraulics, programmable logic controllers, sensor technology,
electrical engineering and electric drives.
The modular design of the training system allows for applications which go above and beyond the
limitations of the individual packages. For example, PLC actuation of pneumatic, hydraulic and electric
drives is possible.
VIII © Festo Didactic GmbH & Co. KG 567258
All training packages contain the following elements:
• Hardware
• Media
• Seminars
Hardware Hardware included in the training packages consists of industrial components and systems that are
specially designed for training purposes. The components contained in the training packages are specifically
designed and selected for the projects included in the accompanying media.
Media The media provided for the individual topics consist of a mixture of teachware and software. The teachware
includes:
• Technical books and textbooks (standard works for conveying basic knowledge)
• Workbooks (practical exercises with supplementary instructions and sample solutions)
• Lexicons, manuals, technical books (which provide technical information on the topics for further
exploration)
• Transparency sets and videos (for easy-to-follow, dynamic instruction)
• Posters (for clear-cut representation of facts)
Within the software category, the following programs are available:
• Digital training programs (learning content specifically prepared for the purpose of virtual training)
• Simulation software
• Visualisation software
• Software for acquiring measurement data
• Project engineering and design engineering software
• Programming software for programmable logic controllers
The teaching and learning media are available in several languages. They’re intended for use in classroom
instruction, but are also suitable for self-study.
Seminars Comprehensive seminar offerings covering the contents of the training packages round off the system for
training and vocational education.
If you have suggestions or feedback about this manual,
please send us an e-mail at [email protected].
The authors and Festo Didactic look forward to your comments.
© Festo Didactic GmbH & Co. KG 567258 IX
Introduction
This workbook is part of the learning system for automation technology from Festo Didactic GmbH & Co. KG.
The system provides a solid basis for practice-oriented training and vocational education. Training package
TP 230 deals with the subject of “Fundamentals of vacuum technology”.
Topics including vacuum generation, system design, the selection of suction grippers and typical circuits
with suction grippers are dealt with in depth. In addition, reducing compressed air consumption in vacuum
systems is also addressed.
A permanent workstation equipped with a Festo Didactic profile plate is a prerequisite for setting up the
controllers. The profile plate has 14 parallel T-slots at 50 mm intervals. A power supply unit with short-
circuit protection is used as a direct voltage source (input: 230 V, 50 Hz, output: 24 V, max. 5 A). A portable
compressor with silencer (230 V, approx. 50 litres per minute, max. 800 kPa = 8 bar) can be used for
compressed air supply.
Working pressure should not exceed 600 kPa (6 bar). Ideal control sequence reliability can be achieved by
operating the controller at a working pressure of 500 kPa (5 bar) without oil.
In addition to equipment set TP 230, you’ll also need components from equipment set TP 201 in order to
complete the 6 exercises. The theoretical fundamentals for understanding this workbook are included in the
textbook entitled
• “Pneumatics/electropneumatics”,
as well as in the appendix to this workbook.
Technical data for the individual components are also available (vacuum generators, suction cups, vacuum
switches etc.).
X © Festo Didactic GmbH & Co. KG 567258
Safety precautions and work instructions
General Trainees should only work with the controllers under the supervision of a trainer.
Observe specifications included in the technical data for the individual components and in particular all
safety instructions!
Mechanical setup • Mount all of the components securely onto the profile plate.
• Limit switches should not be actuated frontally.
• Danger of injury during troubleshooting!
• Use a tool to actuate the limit switches, for example a screwdriver.
• Only reach into the setup when it’s at a complete standstill.
Electrical setup • Electrical connections must only be established and interrupted in the absence of voltage!
• Only use connecting cables with safety plugs for electrical connections.
• Only use low voltage (max. 24 V DC).
Pneumatic setup • Do not exceed the maximum permissible pressure of 600 kPa (6 bar).
• Do not activate compressed air until all the tubing connections have been completed and secured.
• Do not disconnect tubing while under pressure.
• Danger of injury when switching compressed air on!
Cylinders may advance and retract automatically.
• Danger of accident due to tubing slipping off!
Use shortest possible tubing connections.
Wear safety glasses.
In the event that tubing slips off:
Switch compressed air supply off immediately.
• Pneumatic circuit setup:
Connect the components with plastic tubing with an outside diameter of 4 or 6 mm. Push the tubing into
the push-in connector as far as it will go.
Switch compressed air supply off before dismantling the circuit.
• Dismantling the pneumatic circuit:
Press the blue release ring down, after which the tubing can be pulled out.
© Festo Didactic GmbH & Co. KG 567258 XI
The mounting boards for the devices are equipped with mounting variants A through D:
Variant A, snap-in system Lightweight components that are not load-bearing (e.g. directional control valves). Simply clip the device
into the slot on the profile plate. Release the components from the slots by turning the blue lever.
Variant B, bolt system Components with medium load capacity (e.g. actuators). These components are clamped onto the profile
plate using T-head bolts. The blue, knurled nut is used for clamping and loosening.
Variant C, screw system For components with high load capacity and components which are seldom removed from the profile plate
(e.g. on-off valve with filter regulator). The elements are secured with socket head screws and T-head bolts.
Variant D, plug-in system Lightweight components with lock pins which cannot be subjected to loads (e.g. indicators). These are
mounted using plug adapters.
Observe the specifications in the technical data for the individual components.
XII © Festo Didactic GmbH & Co. KG 567258
Technology package for electropneumatics (TP 200)
The TP 200 technology package consists of a multitude of individual training materials and seminars. This
package is only about the topic of electropneumatic controllers. Individual components included in the
TP 200 technology package can also be included in other packages.
Important TP 200 components • Permanent workstation with Festo Didactic profile plate
• Compressor (230 V, 0.55 kW, max. 800 kPa = 8 bar)
• Equipment sets or individual components
• Optional training materials
• Practical training models
• Complete laboratory setups
Training documentation
Textbooks Pneumatics/electropneumatics
Fundamentals of pneumatic control technology
Maintenance of pneumatic components and systems
Workbooks Fundamentals of vacuum technology, TP 230
Optional teachware Set of transparencies and overhead projector
Magnetic symbols, drawing template
Electropneumatics WBT, pneumatics WBT
Electrical engineering WBTs 1 and 2, electronics WBTs 1 and 2
Set of cutaway models with storage case
FluidSIM® pneumatic simulation software
Seminars
P111 Fundamentals of pneumatics and electropneumatics
P121 Maintenance and troubleshooting for pneumatic and electropneumatic systems
P-OP Tracking down waste – economic use of pneumatics
IW-PEP Repair and maintenance in control technology – pneumatic and electropneumatic systems
P-AL Pneumatics for vocational education
P-AZUBI Pneumatics and electropneumatics for trainees
VUU Using vacuum in handling technology
P-KOMPAKT Intensive training in pneumatics and electropneumatics
Please refer to the current seminar schedule for locations, dates and prices.
You’ll find further training materials in our catalogue and on the Internet. The learning system for
automation technology is continuously updated and expanded. Transparency sets, videos, CD-ROMs and
DVDs, as well as textbooks, are available in several languages.
© Festo Didactic GmbH & Co. KG 567258 XIII
Learning objectives for the advanced level (TP 230)
• Be able to generate a partial vacuum.
• Become familiar with the function of a venturi nozzle.
• Become familiar with the effects of system pressure on the degree of vacuum achieved and on the
evacuation time with different vacuum generators.
• Become familiar with the effects of throttle points (e.g. thin or long tubing lengths, clogged silencers) on
vacuum generation.
• Be able to control and adjust vacuum.
• Become familiar with the effects of diameter on suction cup holding force.
• Be able to select suitable suction cups for various workpieces.
• Become familiar with the effects of workpiece surface on suction cup holding force.
• Become familiar with the effects of workpiece surface on holding force.
• Become familiar with the methods for maintaining vacuum in the event that, when using several suction
cups, not all of them retain their grip.
• Be able to grip workpieces without flat surfaces using vacuum grippers.
• Be able to monitor partial vacuum with a pressure switch.
• Be able to perform this type of monitoring under various conditions.
• Be able to set up a circuit which makes it possible to minimise compressed air consumption in a vacuum
system.
• Be able to calculate the cost savings and amortisation time for compressed air economy circuits.
• Be able to release workpieces from the suction gripper in a controlled fashion after transport has been
completed using a compressed air economy circuit.
XIV © Festo Didactic GmbH & Co. KG 567258
Allocation of learning objectives per exercise
Exercise 1 2 3 4 5 6
Learning objectives
Be able to generate a partial vacuum. • Become familiar with the function of a venturi nozzle. • Become familiar with the effects of system pressure on
the degree of vacuum achieved and on the evacuation
time with different vacuum generators. •
Become familiar with the effects of throttle points (e.g.
thin or long tubing lengths, clogged silencers) on
vacuum generation. •
Be able to control and adjust vacuum. • • • Become familiar with the effects of diameter on
suction cup holding force. •
Be able to select suitable suction cups for various
workpieces. •
Become familiar with the effects of workpiece surface
on suction cup holding force. •
Become familiar with the effects of workpiece surface
on holding force. •
Become familiar with the methods for maintaining
vacuum in the event that, when using several suction
cups, not all of them retain their grip. •
Be able to grip workpieces without flat surfaces using
vacuum grippers. • •
Be able to monitor partial vacuum with a pressure
switch. •
Be able to perform this type of monitoring under
various conditions. •
Be able to set up a circuit which makes it possible to
minimise compressed air consumption in a vacuum
system. •
Be able to calculate the cost savings and amortisation
time for compressed air economy circuits. •
Be able to release workpieces from the suction gripper
in a controlled fashion after transport has been
completed using a compressed air economy circuit. •
© Festo Didactic GmbH & Co. KG 567258 XV
Equipment set for the advanced level (TP 230)
The equipment set has been put together for basic training in the field of electro-pneumatic control
technology. It includes all the elements which are necessary for achieving the specified learning objectives,
and can be supplemented with any other equipment sets. A profile plate, an electrical power supply unit,
various components from TP 201 and a source of compressed air are also required in order to set up
functional controllers.
Equipment set (TP 230)
Designation Order no. Quantity
Suction cup (black), 20 mm 573043 1
Suction cup (black), 30mm 573044 1
Suction cup (transparent), 20 mm 573045 1
Suction cup (transparent), 30mm 573046 1
Bellows suction cup, 3.5 convolutions (transparent), 20 mm 573047 2
Oval suction cup, 4 x 20 mm 573057 4
Vacuum generator 05 H 573258 1
Vacuum generator 05 L 573259 1
Air reservoir 152912 1
Non-return valve 153462 1
Flow control valve 193972 1
Vacuum gauge 573042 1
Vacuum switch 548624 1
Required components from TP 201
Designation Order no. Quantity
3/2-way solenoid valve, normally closed 539776 1
5/2-way solenoid valve as 3/2, normally open 539777 1
Signal input, electrical 162242 1
Relay, 3-way 162241 1
Distributor block 152896 1
Push-in T-connector 153128 2
On-off valve with filter-regulator 540691 1
XVI © Festo Didactic GmbH & Co. KG 567258
Equipment set symbols
Designation Symbol
Relay, 3-way
1412 2422 3432
32
4442
11 21 31 41
A1
A2
1412 2422 34 4442
11 21 41
A1
A2 31
1412 2422 3432 4442
11 21 31 41
A1
A2
Signal input, electrical 13 21
14 22
13 21
14 22
13 21
14 22
13 21
14 22
3/2-way solenoid valve,
normally closed
2
1M131
1M1
12
© Festo Didactic GmbH & Co. KG 567258 XVII
Designation Symbol
5/2-way solenoid valve
Air reservoir
Vacuum switch
p
Non-return valve
1
2
Flow control valve
1
2
Vacuum generator
2
31
Suction cup
XVIII © Festo Didactic GmbH & Co. KG 567258
Allocation of components per exercise
Exercise 1 2 3 4 5 6
Component
Suction cup (black), 20mm 1
Suction cup (black), 30mm 1
Suction cup (transparent), 20mm 1
Suction cup (transparent), 30mm 1
Bellows suction cup, 3.5 convolutions
(transparent), 20 mm with suction valve 1 2 2 2 2
Oval suction cup, 4 x 20 mm 1
Vacuum generator 05 L 1 1 1
Vacuum generator 05 H 1 1 1 1 1 1
Air reservoir 1
Non-return valve 1 1
Flow control valve 1 (1)
Vacuum gauge 1 1 1
Vacuum switch 1 1 1
The following components from the TP 201 training package are also required.
Exercise 1 2 3 4 5 6
Component
Suction cup (black), 20mm 1
3/2-way solenoid valve, normally closed 1 1 1 1 1 1
5/2-way solenoid valve as 3/2, normally
open 1 1 1
Pressure regulator 1 1 1 1 1 1
Signal input, electrical 1 1 1 1 1 1
Relay, 3-way 1 1 1 1 1 1
Distributor block 1 1 1 1 1 1
On-off valve with filter-regulator 1 1 1 1 1 1
Power supply unit, 24 V DC 1 1 1 1 1 1
© Festo Didactic GmbH & Co. KG 567258 XIX
Tools for the trainer
Learning objectives The basic learning objectives for the exercises are the systematic drafting of circuit diagrams, as well as the
practical setup of the controller on the profile plate. This direct interaction involving both theory and
practice ensures faster progress. Concrete, individual learning objectives are assigned to each exercise.
Important learning objectives are in parentheses in the revision sections.
Equipment set elements The exercise book and the equipment set match each other. For all the exercises, you’ll only need the
elements included in the equipment set for the TP 201 basic level.
Each exercise in the basic level can be set up on a profile plate.
Structure of the exercises
All the exercises in part A have the same structure and layout and are broken down into:
• Title
• Learning objectives
• Problem description
• Parameters
• Project assignment
• Worksheets
The trainer’s manual includes the solutions for all the exercises.
Component designations
Pneumatic components are designated in circuit diagrams in accordance with ISO 1219-2. All the
components included in any given circuit have the same primary identifying number. Letters are assigned
depending on each respective type of component. Consecutive numbers are assigned if several components
of the same type are included within a single circuit. Pressure lines are designated with a P and are
numbered separately.
Drives: 1A1, 2A1, 2A2 ...
Valves: 1V1, 1V2, 1V3, 2V1, 2V2, 3V1 ...
Sensors: 1B1, 1B2 ...
Signal inputs: 1S1, 1S2 ...
Accessories: 0Z1, 0Z2, 1Z1 ...
Pressure lines: P1, P2 ...
XX © Festo Didactic GmbH & Co. KG 567258
CD-ROM contents The workbook is included on the CD-ROM as a PDF file. The CD-ROM also provides you with additional
media.
The CD-ROM contains the following folders:
• Technical data
• Demo
• Festo catalogue
Technical data The technical data for the components included in the technology package are available as PDF files.
Demo A demo version of the FluidSIM® pneumatics software package is included on the CD-ROM. Even this demo
version is suitable for testing controllers developed by the user.
Festo catalogue You’re provided with the pages from the Festo AG & Co. KG catalogue for specific components. The
representations and descriptions of the components in this format are intended to demonstrate how the
components are presented in an industrial catalogue. Additional information about the components is also
included.
© Festo Didactic GmbH & Co. KG 567258 1
Exercises and solutions
Exercise 1: Generating vacuum _______________________________________________________________ 3
Exercise 2: Selecting suction cups for various workpieces _______________________________________ 11
Exercise 3: Maintaining vacuum when using more than one suction cup ____________________________ 21
Exercise 4: Monitoring partial vacuum _______________________________________________________ 29
Exercise 5: Reducing compressed air consumption in a vacuum system ____________________________ 37
Exercise 6: Controlled release of workpieces retained by a vacuum ________________________________ 43
2 © Festo Didactic GmbH & Co. KG 567258
© Festo Didactic GmbH & Co. KG 567258 3
Exercise 1 Generating vacuum
Learning objectives After completing this exercise:
• You’ll be able to generate a partial vacuum.
• You’ll be familiar with the function of a venturi nozzle.
• You’ll be familiar with the effects of system pressure on the degree of vacuum achieved and on the
evacuation time with different vacuum generators.
• You’ll be familiar with the effects of throttle points on vacuum generation.
• You’ll be able to control and adjust vacuum.
Problem description A handling unit for different workpieces needs to be developed. Your job is to examine various components
and investigate the possible use of vacuum technology. First of all, you’ll have to examine components used
for vacuum generation.
Parameters • Use the vacuum generators included in the equipment set.
Project assignment 1. Describe the mode of operation of a vacuum generator.
2. Set up the test circuit.
3. Measure the vacuum generated and the evacuation time with various vacuum generators.
4. Draw characteristic curves for both vacuum generators.
5. Compare the two vacuum generators and describe their differences.
6. List any possible negative effects on vacuum generation.
Exercise 1 – Generating vacuum
4 © Festo Didactic GmbH & Co. KG 567258
Mode of operation of a vacuum generator based on the venturi principle
– Name the various components and ports of the vacuum generator shown below. Enter the
corresponding designations to the right of the numbers in the table.
Exhaust port, supply port, collector nozzle, jet nozzle, vacuum port
4
5
1
2 3
Vacuum generator
Number Designation
1 Supply port
2 Jet nozzle
3 Collector nozzle
4 Exhaust port
5 Vacuum port
– Describe the mode of operation of the vacuum generator based on the venturi principle.
Compressed air flows from the supply port (1) through a restriction, i.e. the vacuum generator’s jet
nozzle (2). Air flow velocity is increased at this restriction to ultrasonic speeds. After the air exits the
jet nozzle, it expands and flows through the collector nozzle (3) and out of the exhaust port (4). Partial
vacuum occurs in the chamber around the jet nozzle during this process. As a result, air is drawn in
through the vacuum port.
Exercise 1 – Generating vacuum
© Festo Didactic GmbH & Co. KG 567258 5
Measuring the degree of partial vacuum generated with various vacuum generators
Set up the controller in accordance with the circuit diagram shown below. Measure the degree of partial
vacuum achieved with the vacuum generator at different system pressures. Compare the two vacuum
generators included in the equipment set.
– Enter the acquired values in the table below.
12
22
32
42
.2
.3
14
24
34
44
11
21
31
41
K1
14 2412 22
11 21
1
S1
K1 1M1
+24 V 32
0 V
A1
A2
K1
S2
31
13
32
14
2
1M131
1V1
2
31
1V2
1V3
1Z1
2
31
System
pressure
Vacuum generator VN-05-H-T3-PQ2-VQ2-RQ2 Vacuum generator VN-05-L-T3-PQ2-VQ2-RQ2
Degree of partial vacuum achieved (bar) Degree of partial vacuum achieved (bar)
1 bar -0.08 0
2 bar -0.34 -0.14
3 bar -0.54 -0.2
4 bar -0.7 -0.3
5 bar -0.77 -0.38
6 bar -0.8 -0.42
Exercise 1 – Generating vacuum
6 © Festo Didactic GmbH & Co. KG 567258
Drawing the partial vacuum curve
– Enter the characteristic curves of both vacuum generators for the degree of partial vacuum achieved in
the diagram below (pu = partial vacuum, p = system pressure).
1 42 53 7
-0,1
-0,5
-0,2
-0,6
-0,3
-0,7
-0,4
-0,8
-1,0
p
VN-05-H-T3-PQ2-VQ2-RQ2
VN-05-L-T3-PQ2-VQ2-RQ2
pU
Degree of partial vacuum achieved relative to operating pressure
Exercise 1 – Generating vacuum
© Festo Didactic GmbH & Co. KG 567258 7
Measuring evacuation time for both vacuum generators
Set up the circuit described above in accordance with the circuit diagram shown below. In order to be able
to compare the performance of the two vacuum generators included in the equipment set, elapsed time is
measured from the moment operating pressure (6 bar) is switched on until a defined degree of partial
vacuum is reached.
Note:
The reservoir is required in order to ensure that the amount of time required for evacuation is actually
measurable, and thus simulates evacuation of a larger vacuum system. Use a clock or a stopwatch to
measure elapsed time.
12
22
32
42
.2
.3
14
24
34
44
11
21
31
41
K1
14 2412 22
11 21
1
S1
K1 1M1
+24 V 32
0 V
A1
A2
K1
S2
31
13
32
14
2
1M131
1V1
2
31
1V2
1V3
1Z1
2
31
1Z2
Exercise 1 – Generating vacuum
8 © Festo Didactic GmbH & Co. KG 567258
– Measure evacuation time for all the listed values and enter the evacuation time for both vacuum
generators in the table included below. Set system pressure to 6 bar for this exercise.
Partial
vacuum (bar)
Vacuum generator VN-05-H-T3-PQ2-VQ2-RQ2 Vacuum generator VN-05-L-T3-PQ2-VQ2-RQ2
Evacuation time (s) Evacuation time (s)
-0.1 bar 0.4 -
-0.2 bar 0.8 0.4
-0.3 bar 1.0 0.8
-0.4 bar 1.8 2.0
-0.5 bar 2.4 Max. -0,44 bar
-0.6 bar 3.5
-0.7 bar 5.8
-0.8 bar 10.0
– Enter the determined evacuation times in the graphic shown below, and draw characteristic curves for
both vacuum generators.
-0,4-0,2 pU -0,80
2
4
6
10
0
t (s)
VN-05-H-T3-PQ2-VQ2-RQ2
VN-05-L-T3-PQ2-VQ2-RQ2
Exercise 1 – Generating vacuum
© Festo Didactic GmbH & Co. KG 567258 9
Vacuum generator comparison
– Describe the differences between the two vacuum generators used and their respective advantages for
vacuum generation.
Vacuum generator VN-05-H-T3-PQ2-VQ2-RQ2:
This type of vacuum generator achieves a higher level of vacuum.
The maximum vacuum level is generated with low system pressure.
However, this vacuum generator requires significantly more evacuation time than the other.
This type of vacuum generator should be used when the suction grippers require greater holding
forces, for example in order to reliably retain heavy loads.
Vacuum generator VN-05-L-T3-PQ2-VQ2-RQ2:
This vacuum generator achieves relatively low levels of vacuum in comparison with the other
(approx. 50%).
High system pressure is required in order to reach maximum achievable vacuum.
On the other hand, it needs only minimal evacuation time in order to generate a partial vacuum.
This vacuum generator is used when a large vacuum system has to be evacuated quickly. Type L
vacuum generators are used especially where minimal vacuum and/or short cycle times are required.
Influences on vacuum generation
– Which other influences, in addition to changing system pressure and the size of the system to be
evacuated, might have negative effects on the generation of a partial vacuum by means of a vacuum
generator? Write them down.
Long or restricted tubing connections between the ejector and the suction cup.
Long or restricted compressed air supply line to the ejector.
Contaminated or clogged silencer.
Branch TEEs and angle connectors in the vacuum lines.
Exercise 1 – Generating vacuum
10 © Festo Didactic GmbH & Co. KG 567258
Influence of restrictions on vacuum generation
A flow control valve is installed in the respective line in order to simulate restrictions and other unfavourable
conditions in compressed air or vacuum lines. A restriction can then be simulated by closing the flow control
valve. Set the flow control valve to a specific degree of restriction, and leave this setting unchanged for the
entire duration of the experiment.
– Simulate the influences listed in the table with regard to degree of partial vacuum and evacuation time.
Influence Vacuum generator (type H) Vacuum generator (type L)
Contaminated silencer
Throttle point between the vacuum generator
and the silencer
Evacuation time:
Max. vacuum
Evacuation time:
Max. vacuum
Kink in the vacuum line between the suction
cup and the vacuum gauge, and between the
vacuum generator and the vacuum gauge.
If there’s a kink at either of these places,
vacuum collapses at the suction cup.
However, if the kink is located between
the vacuum gauge and the suction cup,
vacuum is still indicated.
If there’s a kink at either of these places,
vacuum collapses at the suction cup.
However, if the kink is located between
the vacuum gauge and the suction cup,
vacuum is still indicated.
Restriction in the air supply line
Throttle point between the pressure regulator
or the directional control valve and the vacuum
generator
The smaller the throttle cross-section,
the lower the degree of vacuum that can
be achieved
The smaller the throttle cross-section,
the lower the degree of vacuum that can
be achieved
Restriction in the vacuum line
Throttle point between ambient pressure and
the vacuum generator with vacuum gauge in-
between. Simulates a porous workpiece.
The smaller the throttle cross-section,
the lower the degree of vacuum that can
be achieved
The smaller the throttle cross-section,
the lower the degree of vacuum that can
be achieved
Measure evacuation time until the maximum
degree of partial vacuum is achieved (with
reservoir) with varying vacuum line lengths.
10 cm
100 cm
15 seconds
22 seconds
3 seconds
5 seconds