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FAKULTI TEKNOLOGI KEJURUTERAAN MEKANIKAL DAN PEMBUATAN UNIVERSITI TEKNIKAL MALAYSIA MELAKABMMM 2333 PNEUMATIC AND HYDRAULIC TECHNOLOGYLAB SHEET 2DOUBLE ACTING-ROD CYLINDER - PRESSURE INTENSIFICATIONLearning Outcome (LO):LO2 Design and troubleshoot hydraulic and pneumatic system manually and using so...

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LAB 2 FAKULTI TEKNOLOGI KEJURUTERAAN MEKANIKAL DAN PEMBUATAN UNIVERSITI TEKNIKAL MALAYSIA MELAKA BMMM 2333

PNEUMATIC AND HYDRAULIC TECHNOLOGY LAB SHEET 2

DOUBLE ACTING-ROD CYLINDER - PRESSURE INTENSIFICATION Learning Outcome (LO):

LO2

Program Outcome:

PO3

Design and troubleshoot hydraulic and pneumatic system manually and using software. Ability to design solutions for broadly-defined engineering technology problems, and to design systems, components or processes to meet specified needs with appropriate consideration for public health and safety, as well as cultural, societal, environmental and sustainability concerns

Synopsis:

This lab activity will enrich students’ knowledge on hydraulic basic components. Students are exposed to the concept of designing and simulating hydraulic circuit through simulation software.

Related Lecture’s Topic:

1. H&P Actuators (Topic 6)

Prepared by:

Ts Muhammad Fairuz bin Abu Bakar

Date: 9 Nov 2020

Approved by LM/SLM/HOD

Dr Ilman Hakimi

Date

QMS : REVISION RECORDS Revision No

Description

Date (DD/MM/YY)

Prepared by :

Approved by LM/SLM/HOD:

1.0 THEORY HYDRAULIC CYLINDER The hydraulic cylinder converts hydraulic energy into mechanical energy. It generates linear movements. For this reason, it is also referred to as a “linear motor”. There are two basic types of hydraulic cylinder • single-acting and • double-acting cylinders. HOW IT WORK? The working fluid normally hydraulic oil is delivered under pressure through the cylinder ports in the piston or annular area of the cylinder; this pressure, exercised on the piston or annular area leads to the development of linear motion of the piston and the piston rod. Consequently, the motion of the piston rod is transmitted to the machine that the piston rod is fitted to. In order to maintain the hermetic piston-to-rod seal, space for the sealing element has to be provided in the cylinder design. SYMBOLS Cylinder type

Symbol

Single acting cylinder with single piston rod

Characteristic Force operates only in one direction. Return stroke of piston rod achieved by means of external force.

Double acting cylinder with single piston rod

Force operates in both directions. Different piston areas on both sides of the piston due to the piston rod. Fig1.0

CONSTRUCTION

1) Piston 2) Piston rod 3) Piston rod bearing 4) Annular piston surface 5) Piston surface Fig1.1 Double Acting Cylinder

In the case of double-acting cylinders, both piston surfaces can be pressurized. Therefore, it is possible to perform a working movement in both directions. These cylinders operate according to the following principle: The hydraulic fluid flows into the piston area and pressurises the piston surface. Internal and external resistances cause the pressure to rise. As laid down in the law F = p ⋅ A, a force F is produced from the pressure p and the piston surface area A. Consequently, the resistances can be overcome and the piston rod extends. This is possible owing to the conversion of hydraulic energy into mechanical energy which is made available to a consuming device.

Fig1.2 It should be borne in mind that when the piston extends the oil on the piston rod side must be displaced via the lines into the reservoir. During the return stroke, the hydraulic fluid flows into the (annular) piston rod area. The piston retracts and the oil quantity is displaced from the piston area by the piston.

Fig1.3 In double acting cylinders with a single-sided piston rod, different forces (F= p ⋅ A) and speeds are produced for the same flow rate on extension and retraction owing to the differing surfaces (piston surface and annular piston surface). The return speed is higher since, although the flow rate is identical, the effective surface is smaller than for the advance stroke. The following equation of continuity applies:

FLOW CONTROL VALVE Flow control valves are used to reduce the speed of a cylinder or the r.p.m. of a motor. Since both values are dependent on the flow rate, this must be reduced. However, fixed displacement pumps supply a uniform flow rate. Reduction in the rate of flow supplied to the drive element is achieved according to the following principle: A reduction in the flow cross-section in the flow control valve causes an increase in pressure ahead of this. This pressure causes the pressure relief valve to open and, consequently, results in a division of the flow rate. This division of the flow rate causes the flow volume required for the r.p.m. or speed to flow to the power component and the excess delivery to be discharged via the pressure relief valve. This results in a considerable energy loss. On the basis of their controlling or regulating function, flow control valves are classified as either: • flow control valves or • flow regulating valves.

Application of 2-way flow control valve a) Meter-in (primary control) b) Meter-out (secondary control) Meter-in (extension)

All flow entering a work cylinder is first metered through a flowcontrol valve. Since this metering action involves reducing flow from a pump to a work cylinder, a pump must deliver more fluid than is required to actuate a cylinder at the desired speed. Excess fluid returns to a tank through a relief valve. To conserve power and avoid undue stress on a pump, a relief valve’s setting should be only slightly higher than a working pressure’s, which a cylinder requires.A meter-in circuit is ideal in applications where a load always offers a positive resistance to flow during a controlled stroke.

Fig1.3

Examples would be feeding grinder tables, welding machines, milling machines, and rotary hydraulic motor drives. A flowcontrol-and-check valve used in this type of circuit would allow reverse free flow for the return stroke of a cylinder, but it would not provide control of return stroke speed.

Meter-out (extension)

A flow-control valve is installed on the return side of a cylinder so that it controls a cylinder’s actuation by metering its discharge flow. A relief valve is set slightly above the operating pressure that is required by the type of work. This type of circuit is ideal for overhauling load applications in which a workload tends to pull an operating piston faster than a pump’s delivery would warrant. Examples would be for drilling, reaming, boring, turning, threading, tapping, cutting off, and cold sawing machines. A flow-control-and-check valve used in this circuit would allow reverse free flow, but it would not provide a control of return stroke speed.

Fig1.4 Pressure Intensification Force produced by a hydraulic cylinder is a product of pressure and area (F = p x A). In a conventional double-acting cylinder, the effective area and therefore force produced by the piston and rod sides of the cylinder are unequal. It follows that if the rod side of the cylinder has half the effective area of the piston side, it will produce half the force of the piston side for the same amount of pressure. The equation F = p x A can be transposed as p = F/A: that is, pressure equals force divided by area. For the rod side of the cylinder to resist the force developed by the piston side, with only half the area, then the pressure needs to be doubled. This means that if the piston side is pressurized to 3,000 PSI, a pressure of 6,000 PSI will be required on the rod side to produce an equal force, which explains why pressure intensification can occur in a double-acting cylinder. Pressure intensification occurs when a throttle valve in the discharge side is completely closed. With same forces, the following applies : FK = FR PK.AK = PR.AR PR = AK . PK AR = ϕ . PK

Fig1.5

2.0 EQUIPMENTS/ EXPERIMENT APPARATUS/ CONSUMABLE MATERIALS i. ii.

FluidSIM-H software Problem Desription

Problem Desription A boiler door is opened and closed with a double-acting cylinder. The cylinder is controlled with a 4/2way valve. The customer installed a throttle valve on the piston rod side and, while adjusting the extension velocity, recognizes that the pressure upstream of the throttle becomes higher than the set system pressure. Apart from the technical documentation he wishes to get an explanation of the pressure intensification of the double acting-rod cylinder.

Fig1.5

Description of the process • When the 4/2-way hand lever valve is actuated, the cylinder is advanced. • When the 4/2-way hand lever valve is reset, the cylinder is retracted.

3.0 PROCEDURES/ METHODOLOGY i. ii. iii. iv. v. vi.

A group should consist of max FIVE students. Complete the equipment list in Table 1.0. Draw the hydraulic circuit as in Fig1.6 in the FESTO FluidSIM-H software. Run the simulation. Record the required data in Table1.1. Calculate pressure intensification theoretical value.

4.0 RESULTS You should explain the following items that related to your Lab activity: i.

Procedure – Create equipment list Table1.0 Item

Qtty

Component Description

1

Cylinder, double-acting

2

Pressure Gauge

3

4/2 way hand lever valve

4

Throttle valve

5

On-Off valve

Component Designation

*Component Symbol

Table 1.0: Equipment List *may snip from Fluidsim software

ii.

Work Process - Draw the hydraulic circuit as in Fig1.6 in the FESTO FluidSIM-H software - *Define all the important parameters. • Pump unit – Operating Pressure, Flow, Internal Leakage • Cylinder – Max Stroke, Piston Diameter, Piston Ring Diameter, Display Quantity (Velocity) - Run the simulation. • Actuate valve 1V1 by pressing the hand lever. - Record the data. * Refer to Appendix 2 for parameter settings.

Fig 1.6 Hydraulic circuit diagram. iii. Outcome – Pressure measuring & Pressure Intensification Calculation Pressure measuring Throttle Valve Opening (%) 100 20

System Pressure 0Z1 (bar)

Piston Side 1Z1 (bar)

Cylinder Piston Rod Side Extending Speed 1Z2 (bar) m/s

10 5 0

Table 1.1 Pressure measurement Pressure Intensification Calculation 𝜋

 Piston base area

AK

 Piston rod area

ASt = 4 . dSt 2

 Piston ring area

AR = AK - ASt

 Intensification ratio of the cylinder

ϕ

=

4

. dK 2

=

𝜋

=

AK AR

=

= =

Cylinder Retracting Speed m/s



*Pressure intensification

PR = ϕ . PK

=

* occurs when a throttle valve in the discharge side is completely closed (0% opening).

5.0 DISCUSSION For discussion, you should answer all questions as follows: 1.

Describe the function of using throttle valve in this project.

2.

Explain the relationship of throttle valve opening to cylinder speed.

3.

Explain the relationship of throttle valve opening to back pressure.

4.

Suggest solutions to problems arising in (3).

6.0 CONCLUSION Conclude your findings from this experiment based on pressure intensification recorded vs calculation.

7.0 OTHERS The report must be prepared as APPENDIX.

ASSESSMENT CRITERIA: Your response to each task will be graded separately based on the checklist attached. To obtain maximum marks, ensure that your response addresses each of the tasks in the question accordingly. Assessment checklist for Lab Activity 1 Mark allocation

LO

PO

Procedure (Ability to identify hydraulic components)

10

LO2

PO3

Work Process (Ability to construct hydraulic circuit)

10

LO2

PO3

P2 - Set

Work Process (Ability to perform correct simulation)

15

LO2

PO3

P6 – Adaptaion

Outcome (Results – Pressure Measurement & Pressure Intensification)

25

LO2

PO3

P6 – Adaptaion

Outcome (Explanation of the results)

15

LO2

PO3

P5 - Complex Overt Response

Outcome (Discussion)

15

LO2

PO3

P5 - Complex Overt Response

Outcome (Conclusion)

10

LO2

PO3

P5 - Complex Overt Response

Assessment tasks

TOTAL

100

SPECIFIC INSTRUCTION

1. Answer in ENGLISH . 2. Must include list of references . 3. Submit your assignment ONCE only in a SINGLE file. 4. Submit your assignment ONLINE. 5. Submission date: Week 4 6. This lab report/activity accounts for 5% of the total marks for the course.

C/P/A level

P1 - Perception

APPENDIX 1

LAB 2 FAKULTI TEKNOLOGI KEJURUTERAAN MEKANIKAL DAN PEMBUATAN UNIVERSITI TEKNIKAL MALAYSIA MELAKA BMMM 2333

PNEUMATIC AND HYDRAULIC TECHNOLOGY LAB REPORT 2

DOUBLE ACTING-ROD CYLINDER - PRESSURE INTENSIFICATION

INSTRUCTOR’S NAME

TS. MUHAMMAD FAIRUZ BIN ABU BAKAR STUDENT’S NAME

MATRIX NO:

S1. S2. S3. S4. S5. ASSESSEMENT RUBRICS ASSESSMENT TASK/ITEMS

MARK ALLOCATION

Procedure (Ability to identify hydraulic components) Work Process (Ability to construct and understanding of hydraulic circuit) Work Process (Ability to show data – perform correct simulation) Outcome (Results - Results – Pressure Measurement & Pressure Intensification)

10

5.

Outcome (Explanation of the results)

15

6.

Outcome (Discussion)

15

7.

Outcome (Conclusion)

10

1. 2. 3. 4.

TOTAL MARKS

GIVEN MARKS S1

S2

10 15 25

100

Approved By: ………………………………………………..….. (Instructor’s Signature & Stamp) Date: …………………………………………….........

PROCEDURE – CREATING EQUIPMENT LIST Item

Qtty

Component Description

1

Cylinder, double-acting

2

Pressure Gauge

3

4/2 way hand lever valve

4

Throttle valve

5

On-Off valve

Component Designation

*Component Symbol

Table 1.0: Equipment List

WORK PROCESS – Hydraulic circuit contruction and simulation. 1. Snap shot / print screen of constructed hydraulic circuit on Fluid SIM-H 2. Simple step by step procedure of parameter configuration & performing simulation.

OUTCOME – FLOW RATE & PUMP CURVE Throttle Valve Opening (%) 100

System Pressure 0Z1 (bar)

Piston Side

Cylinder Piston Rod Side Extending Speed

1Z1 (bar)

1Z2 (bar)

m/s

Cylinder Retracting Speed m/s

20 10 5 0

Table 1.1 Pressure measurement Pressure Intensification Calculation 𝜋

. dK 2

=

. dSt 2

=

 Piston base area

AK

 Piston rod area

ASt =

 Piston ring area

AR = AK - ASt

 Intensification ratio of the cylinder

ϕ



Pressure intensification

=

=

4 𝜋 4

AK AR

PR = ϕ . PK

= =

=

OUTCOME (EXPLANATION OF THE RESULTS)  Hydraulic cylinders perform linear (translational) motion and convert hydraulic pressure into ______________.  Double – acting cylinders with _________ areas are known as ____________________.  Differential cylinders function as ___________________ .  Explain pressure intensification recorded vs calculation.

OUTCOME (DISCUSSION) Answer all the questions.

CONCLUSION Conclude your findings from this experiment based on the experiment.

APPENDIX 2 Parameter settings.

Operating Pressure

Flow

max. Stroke

Piston Diameter

Piston Rod Diameter

Throttle Valve Hydraulic Resistance

Mpa

l/min

mm

mm

mm

Mpa/(l/min)2

Group 1,6

16

4.9

200

32

18

0.001

Group 2,7

16

7.5

250

40

22

0.001

Group 3,8

18

11.7

300

50

28

0.001

Group 4

20

18.7

350

63

36

0.001

Group 5

6

2.4

200

16

10

0.001

Component Parameter

Pump Unit

Cylinder...