Plant and Process Engineering 360 PDF
Preview Plant and Process Engineering 360
Plant and Process Engineering 360(cid:2) Note from the Publisher This book has been compiled using extracts from the The extracts have been taken directly from the above following books within the range of Plant and Process source books, with some small editorial changes. Engineeringbooks in theElseviercollection: These changes have entailed the re-numbering of Sections and Figures. In view of the breadth of con- Crowder, (2005) Electric Drives and Electromechanical tent and style of the source books, there is some Systems, 9780750667401 overlap and repetition of material between chapters Laughton and Warne, (2002) Electrical Engineer’s Ref- and significant differences in style, but these features erence Book, 9780750646376 have been left in order to retain the flavour and Parr,(2006)HydraulicsandPneumatics,9780750644198 readability of the individual chapters. Zhang, (2008) Industrial Control Technology, 9780815515715 Endof chapter questions Warne, (2005) Newnes Electrical Power Engineer’s Within the book, several chapters end with a set of Handbook,9780750662680 questions; please note that these questions are for ref- Mobley, (2001) Plant Engineer’s Handbook, erence only. Solutions are not always provided for these 9780750673280 questions. Girdhar,MonizandMackay,(2004)PracticalCentrifugal Pumps: Design, Operation and Maintenance, Unitsofmeasure 9780750662734 Units are provided in either SI or IP units. A conver- Barnes, (2003) Practical Variable Speed Drives and sion table for these units is provided at the end of the Power Electronics,9780750658089 book. Plant and Process (cid:2) Engineering 360 Amsterdam$Boston$Heidelberg$London$NewYork$Oxford Paris$SanDiego$SanFrancisco$Sydney$Tokyo Butterworth-HeinemannisanimprintofElsevier Butterworth-Heinemannisanimprint of Elsevier TheBoulevard,Langford Lane, Kidlington,Oxford OX5 1GB, UK 30Corporate Drive,Suite 400, Burlington,MA 01803,USA First edition 2010 Copyright(cid:2) 2010 ElsevierLtd. Allrights reserved Nopart of thispublication may bereproduced, stored in a retrieval systemortransmitted in anyform or byany means electronic,mechanical, photocopying, recording or otherwise without theprior written permission of the publisher Permissions may be sought directly from Elsevier’sScience & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax(+44) (0) 1865 853333; email: [email protected] you can submit your request online by visiting the Elsevier website at http://elsevier.com/locate/permissions,andselecting Obtainingpermission to useElsevier material Notice Noresponsibility isassumedby thepublisher for anyinjury and/or damage to personsor property asa matter of products liability,negligence or otherwise, orfrom anyuse or operationof any methods,products, instructions or ideas contained in thematerial herein. Because of rapid advances in the medical sciences, in particular, independentverification of diagnoses and drug dosagesshould be made British LibraryCataloguing in Publication Data Acatalogue record for thisbookisavailable from the British Library LibraryofCongress Cataloging-in-Publication Data Acatalogrecord for this book is availabe fromtheLibrary of Congress ISBN–13:978-1-85617-840-2 For information on all Butterworth-Heinemannpublications visit our website at books.elsevier.com Printed and boundin Great Britain 10 10 9 8 7 6 5 4 3 2 1 Contents Section1 INTRODUCTION ................................................................ 1 1.1 Instrumentation and transducers .... .... .... ..... .... .... .... ..... .... .... .... .3 1.2 Controlsystems .... .... ..... .... .... .... ..... .... .... .... ..... .... .... ....43 1.3 Programmable controllers ..... .... .... .... ..... .... .... .... ..... .... .... ...109 1.4 Controlsystems interfacing .... .... .... .... ..... .... .... .... ..... .... .... ...165 Section2 MOTORSANDDRIVES ......................................................... 255 2.1 Electromechanical systems .... .... .... .... ..... .... .... .... ..... .... .... ...257 2.2 Analysing a drive system . ..... .... .... .... ..... .... .... .... ..... .... .... ...277 2.3 Motors, motor controland drives ... .... .... ..... .... .... .... ..... .... .... ...295 2.4 Variablespeed drives .... ..... .... .... .... ..... .... .... .... ..... .... .... ...317 2.5 Induction motors ... .... ..... .... .... .... ..... .... .... .... ..... .... .... ...341 Section3 ELECTRONICDRIVECONTROL .................................................. 363 3.1 Electronic circuitsand devices . .... .... .... ..... .... .... .... ..... .... .... ...365 3.2 Electronic converters .... ..... .... .... .... ..... .... .... .... ..... .... .... ...381 Section4 POWERTRANSMISSION ....................................................... 411 4.1 Powertransmission . .... ..... .... .... .... ..... .... .... .... ..... .... .... ...413 4.2 Gearsand gearboxes .... ..... .... .... .... ..... .... .... .... ..... .... .... ...431 Section5 HYDRAULICANDPNEUMATICSYSTEMS ........................................... 439 5.1 Hydraulic fundamentals .. ..... .... .... .... ..... .... .... .... ..... .... .... ...441 5.2 Pneumaticfundamentals . ..... .... .... .... ..... .... .... .... ..... .... .... ...489 5.3 Pump types andcharacteristics .... .... .... ..... .... .... .... ..... .... .... ...509 5.4 Centrifugal pumpdesign . ..... .... .... .... ..... .... .... .... ..... .... .... ...519 5.5 Pump hydraulics ... .... ..... .... .... .... ..... .... .... .... ..... .... .... ...537 5.6 Hydraulic pumpsand pressureregulation . .... ..... .... .... .... ..... .... .... ...555 5.7 Actuators . .... .... .... ..... .... .... .... ..... .... .... .... ..... .... .... ...579 Index ........................................................................... 597 v This page intentionally left blank Section One Section One Section One Section One Section One Section One Introduction 1 This page intentionally left blank 1.1 Chapter 1.1 Instrumentation and transducers Parr 1.1.1 Introduction specified accuracy can be obtained. Assuming the accu- racy is maintained across the range, the pressure trans- 1.1.1.1 Definition of terms mitter above has a turndown of 4:1. Orifice plates and otherdifferentialflowmeterslose accuracyatlowflows, Accuratemeasurementofprocessvariablessuchasflow, andtheirturndownislessthanthetheoreticalmeasuring pressure and temperature is an essential part of any in- range wouldimply. dustrial process. This chapter describes methods of Theerrorisameasurementofthedifferencebetween measuring common process variables. the measured value and the true value. The accuracy is Likemosttechnologies,instrumentationhasarangeof the maximum error which can occur between the pro- common terms with precisemeanings. cess variable and the measured value when the trans- Measuredvariableandprocessvariablearebothterms ducer is operating under specified conditions. Error can forthephysicalquantitythatistobemeasuredontheplant beexpressedinmanyways.Thecommonestareabsolute (e.g.thelevelintank15).Themeasuredvalueistheactual value (e.g. (cid:2)2 (cid:3)C for a temperature measurement), as valueinengineeringunits(e.g.thelevelis1252mm). apercentageoftheactualvalue,orasapercentageoffull A primary element or sensor is the device which con- scale. Errors can occur for several reasons; calibration vertsthemeasuredvalueintoaformsuitableforfurther error, manufacturing tolerances and environmental conversion into an instrumentation signal, i.e. a sensor effects are common. connectsdirectlytotheplant.Anorificeplateisatypical Many devices have an inherent coarseness in their sensor. A transducer is a device which converts a signal measuringcapabilities.Awirewoundpotentiometer,for fromonequantitytoanother(e.g.aPT100temperature example,canonlychangeitsresistanceinsmallstepsand transducer converts a temperature to a resistance). A digital devices such as encoders inherently measure in transmitter is a transducer which gives a standard in- discrete steps. The term resolution is used to define the strumentationsignal (e.g. 4–20mA) asanoutput signal, smallest steps in which a readingcan be made. i.e. it converts from the process measured value to Inmanyapplicationstheaccuracyofameasurementis a signal which can beused elsewhere. less important than its consistency. The consistency of ameasurementisdefinedbythetermsrepeatabilityand 1.1.1.2 Range, accuracy and error hysteresis. Repeatability is defined as the difference in readings The measuring span, measuring interval and range are obtained when the same measuring point is approached terms which describe the difference between the lower several times from thesamedirection. and upper limits that can be measured (e.g. a pressure Hysteresis occurs when the measured value de- transducer which can measure from 30 to 120 bar has pends on the direction of approach as Figure 1.1.1. a range of 90 bar). The rangeability or turndown is the Mechanical backlash or stiction are common causes of ratiobetweentheupperlimitandlowerlimitswherethe hysteresis. ElectricalEngineer’sReferenceBook;ISBN:9780750646376 Copyright(cid:2)2002ElsevierLtd.Allrightsofreproduction,inanyform,reserved.
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