Subject: INDUSTRIAL FLUID POWER (A.A. 2023/2024)
Unit AUTOMAZIONE A FLUIDO
Mechanical and energy efficiency technologies (lesson)
Unit Laboratorio di Automazione a Fluido
Other Skills Required for Access to the Job Market (laboratory)
The course is intended to provide the basic knowledge and understanding of the main features and operating modes of the most important fluid power components and systems.
At the end of the “Fluid Automation” course the student should be able to:
- know and understand the main technical and functional features of the hydraulic circuits commonly used in fluid power systems and of their fundamental components (pumps and motors; linear and semi rotary actuators; directional, pressure and flow rate control valves);
- apply the acquired knowledge and ability to understand in order to identify, describe, analyse and evaluate the functional features and performance parameters relating to the different configurations of the aforementioned hydraulic circuits and of their components;
- effectively communicate notions, concepts and models of the main types of hydraulic machines, control valves and circuits for fluid power applications.
For a deeper understanding of the learning objectives, please refer to the expected learning outcomes of the course.
Basic skills and fundamentals of the following disciplines: Technical Physics, Industrial Fluid Dynamics, Mechanical Drawing and Mechanics of Machines.
More in detail, students will need to know the definitions of the main physical quantities and dimensionless groupings commonly used in fluid dynamics (pressure, velocity, density, mass and volumetric flow rate, tangential stress, Reynolds and Froude numbers), with the relative units of measurement, and the key features of the different types of fluid flow (laminar, turbulent and transitional).
Furthermore, students should be able to read and to correctly interpret the technical drawing of a mechanical assembly or component and to identify and understand its constructive and functional features.
The number of hours dedicated to the individual topics of the course has to be considered as purely indicative. Indeed, during the course of the lessons, there may be variations due to interactions with students.
- Hydraulic fluids (6 hours): classification of the main types of fluids used in fluid power systems (mineral oils, fire resistant and synthetic fluids) and of their features and fundamental properties (dynamic and kinematic viscosity, density, characteristic temperatures and bulk modulus).
- Hydraulic symbology (4 hours): principles and rules of usage of the fundamental symbols for the correct representation of the schemes of hydraulic and pneumatic circuits (technical reference standards: UNI ISO 1219-1:1994 e UNI ISO 1219-2:1998).
- Hydraulic circuits (4 hours): classification of the main types of hydraulic circuits (power units and groups with linear and rotary actuators). Presentation, reading and understanding of some examples of elementary and complex hydraulic circuits.
- Positive displacement hydraulic pumps (8 hours): representation symbology, general classification, nomenclature and theoretical formulas for studying the operating modes of positive displacement hydraulic pumps. Fundamental relationships for defining the efficiency parameters (volumetric, hydro-mechanical and global) and their trends with respect to the hydraulic pump operating conditions. Presentation and detailed description of some significant examples of rotary (vane and external gear) and alternative (single cylinder, simple and double acting, and multi-cylinder, with axial and radial pistons) positive displacement hydraulic pumps.
- Hydraulic linear and semi rotary actuators (8 hours): representation symbology, general classification, nomenclature and theoretical formulas for studying the operating modes of hydraulic linear and semi rotary actuators. Fundamental relationships for defining the efficiency parameters (volumetric, mechanical and global) and their trends with respect to the actuator operating conditions. Presentation and detailed description of some significant examples of simple and double acting hydraulic cylinders (standard, through-rod and differential) and of semi rotary hydraulic actuators.
- Positive displacement hydraulic motors (6 hours): representation symbology, general classification, nomenclature and theoretical formulas for studying the operating modes of positive displacement hydraulic motors. Fundamental relationships for defining the efficiency parameters (volumetric, hydro-mechanical and global) and their trends with respect to the hydraulic motor operating conditions. Presentation and detailed description of some significant examples of rotary (external gear, vane and orbital) and alternative (axial, swash-plate and bent-axis, and radial pistons) positive displacement hydraulic motors.
- Proportional and on/off control valves (6 hours): representation symbology, general classification, mechanical features, operating modes and characteristic curves of the main types of proportional and on/off directional, pressure and flow rate control valves.
- Laboratory exercises (12 hours): practical computer exercises aimed at the development of spreadsheets for estimating and assessing the properties of hydraulic fluids and for analysing the operation and predicting the performance of hydraulic machines, components and elementary circuits, commonly used in fluid power systems and applications.
The lessons will be held in presence and in Italian language. Teaching methods include: - theoretical lectures in the classroom, that will be carried out through the aid of audiovisual media (mainly presentations with animated slides); - practical computer exercises, that will be held at the DISMI computer laboratories, aimed at the development of spreadsheets for estimating and assessing the properties of hydraulic fluids and for analysing the operation and predicting the performance of hydraulic machines, components and elementary circuits, commonly used in fluid power systems and applications. Attendance to both theoretical lectures and laboratory exercises is optional. Furthermore, in order to receive clarifications, explanations and personalized tutoring, student reception can be scheduled, only by appointment agreed by e-mail.
The examination will take place at the end of the course, according to the official calendar of the exam sessions that, well in advance, will be published by the teacher on the Esse3 website (https://www.esse3.unimore.it). The final examination is based on a single written test, lasting a maximum of two hours. During the execution of the exam, the use of checkered protocol sheets made available by the teacher is only allowed. The final examination is made by three theoretical questions, aimed at verifying that the student has achieved the learning objectives of the course. The candidate will have to provide open textual answers, possibly also accompanied with drawings, tables, diagrams and analytic equations. During the examination, it is not allowed to use electronic and/or computer devices, as well as notes, books, handouts and manuals. For each of the aforementioned three questions, the maximum achievable score will be clearly indicated on the text of the exam test. The evaluation indicators of the exam are the following: - ability to use and connect knowledge; - ability to discuss and deepen topics; - mastery of the technical terminology; - ability to synthesize, order and clarity of presentation. The grade achieved at the end of the exam will be computed as the sum of the scores obtained for the three theoretical questions (for an overall score equal or higher than 31, the final grade is: 30 cum laude). The final results of the examination will be communicated not later than one week from its execution and will be published on the Esse3 website.
1) Knowledge and understanding
- To know, list and describe the classification of the different types of operating fluid commonly used in fluid power applications and the definition of their main physico-chemical properties and related units of measurement.
- To read the scheme of a hydraulic circuit, drawn following the rules prescribed by the UNI ISO 1219 technical reference standard, identifying the main components.
- To read the technical drawing of a hydraulic machine or component, knowing how to identify its fundamental elements and its mechanical and operational features.
- To know the analytic equations useful for studying the operation of positive displacement pumps and motors, of linear and semi rotary actuators and of directional, pressure and flow rate control valves.
2) Applied knowledge and understanding
- To recognize and clearly identify the general structure and the fundamental features of the main types of hydraulic circuit for fluid power applications.
- To select the most suitable types of hydraulic fluid, machines and components to be used in a hydraulic circuit, depending on the technical specifications defining the project and the technical reference standards of the application field.
- To apply simple analytic equations for studying the operation and for estimating the performance, in steady-state conditions, of positive displacement pumps and motors, of linear and semi rotary actuators and of directional, pressure and flow rate control valves.
3) Autonomy of judgment
- To analyze and evaluate the most suitable design solutions in order to optimize the performance parameters of positive displacement pumps and motors, of linear and semi rotary actuators and of directional, pressure and flow rate control valves.
- To express a critical judgment on the fundamental factors that can cause the main operating problems affecting hydraulic machines and components for fluid power applications.
4) Communication skills
- To know the more suitable technical terminology in order to correctly and appropriately describe: the structure of a hydraulic circuit and the technical and functional features of its components; the mechanical features and the operating modes of the main types of hydraulic machines and components.
- To express in a correct and logical way your own knowledge, recognizing the required topic and answering, in an accurate and comprehensive way, to the exam questions.
5) Learning capability
- To apply the learned knowledge and understanding in order to analyze and critically evaluate the technical features, the operating modes and problems, the performance parameters of other hydraulic systems and components not described during the lessons but related to those covered by the teaching (i.e.: hydraulic circuits and components for automotive and aerospace applications).
- To update independently the knowledge and understanding related to the mechanical and technical features, the operating modes and the performance parameters of the hydraulic circuits and components, in light of the evolutions in progress and of the changes that will occur in the scientific and technological fields and in the technical regulations of the fluid power sector.
Testi di riferimento:
1) G. Cantore - “Macchine” - Casa editrice: Esculapio, Bologna - 1999.
2) N. Nervegna - “Oleodinamica e Pneumatica” - Vol. 1, 2, 3 - Casa editrice: Politeko, Torino - 2003.
3) G.L. Zarotti, R. Paoluzzi - “Oleodinamica” - Casa editrice: Imamoter - C.N.R., Ferrara - 2004.
4) G. Forneris - “L’oleoidraulica nell’ambito Industriale e Mobile” - Casa editrice: Assofluid, Milano - 2004.
5) A. Bucciarelli, H. Speich - “Manuale di Oleodinamica” - Casa editrice: Tecniche Nuove Edizioni, Milano - 2018.
Inoltre, durante lo svolgimento del corso e nel rispetto dei diritti d’autore, il docente metterà a disposizione degli studenti presentazioni, appunti e dispense che costituiranno parte integrante del programma di esame. Questo ulteriore materiale didattico sarà caricato sulla piattaforma integrata di Ateneo per la didattica, Teams-Moodle (https://moodle.unimore.it).
Testi di consultazione:
1) J.F. Blackburn, G. Reethof, J.L. Shearer - “Fluid Power Control” - Casa editrice: The Technology Press of M.I.T., New York (USA), 1960.
2) H.E. Merritt - “Hydraulic Control Systems” - Casa editrice: John Wiley & Sons, Hoboken, New Jersey (USA) - 1991.
3) J. Ivantysyn, M. Ivantysynova - “Hydrostatic Pumps and Motors: Principles, Design, Performance, Modelling, Analysis, Control and Testing” - Casa editrice: Tech Books International, Gautam Buddh Nagar (India) - 2003.
4) N.D. Manring, R.C. Fales - “Hydraulic Control Systems” - Casa editrice: John Wiley & Sons, Hoboken, New Jersey (USA) - 2019.