1、BRITISH STANDARD CONFIRMED OCTOBER 1990 BS 5791-1: 1979 ISO 3857-I: 1977 Glossary of terms for Compressors, pneumatic tools and machines Part 1: General ISO title: Compressors, pneumatic tools and machines Vocabulary Part 1: General UDC 621.51/54BS5791-1:1979 This British Standard, having been prepa
2、red under the directionof the Mechanical Engineering Standards Committee, was published underthe authority of the Executive Board and comes intoeffect on 31October1979 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference MEE/39 Draft for comment 75/74136
3、DC ISBN 0 580 10913 5 Cooperating organizations The Mechanical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The organizations marked with a
4、n asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Associated Offices Technical Committee Department of Trade (Marine Division) Association of Consulting Engineers Electricity Supply Industry
5、in England and Association of Hydraulic Equipment Wales* Manufacturers Engineering Equipment Users Association* Association of Mining, Electrical and Federation of Manufacturers of Construction Mechanical Engineers Equipment and Cranes British Compressed Air Society* Health and Safety Executive* Bri
6、tish Electrical and Allied Manufacturers Institution of Gas Engineers* Association (BEAMA)* Institution of Mechanical Engineers* British Gas Corporation* Institution of Plant Engineers British Gear Manufacturers Association Institution of Production Engineers British Internal Combustion Engine Lloyd
7、s Register of Shipping Manufacturers Association London Transport Executive British Pump Manufacturers Association Machine Tool Industry Research Association British Steel Corporation Ministry of Defence* British Steel Industry National Coal Board* British Valve Manufacturers Association Oil Compani
8、es Materials Association Chartered Institution of Building Services* Process Plant Association Crown Agents for Oversea Governments and Railway Industry Association of Great Britain Administrations Society of Motor Manufacturers and Traders Department of Industry (Mechanical Limited Engineering) Tel
9、ecommunication Engineering and Department of Industry (National Engineering Manufacturing Association (TEMA) Laboratory) Water-tube Boilermakers Association Department of the Environment British Chemical Engineering Contractors Imperial College of Science and Technology Association Institute of Mari
10、ne Engineers CBMPE Institution of Mining and Metallurgy Contractors Plant Association Institution of Mining Engineers Imperial Chemical Industries Limited South Wales Institute of Engineers Amendments issued since publication Amd. No. Date of issue CommentsBS5791-1:1979 BSI 10-1999 i Contents Page C
11、ooperating organizations Inside front cover National foreword ii Scope and field of application 1 Pressures 1 2 Temperatures 1 Annex A References 5 Table 1 Symbols and units 2 Table 2 Letters used as symbols 3 Table 3 Letters and figures used as subscripts 4 Publications referred to Inside back cove
12、rBS5791-1:1979 ii BSI 10-1999 National foreword This British Standard was prepared under the direction of the Mechanical Engineering Standards Committee and is identical with ISO 3857-I “Compressors, pneumatic tools and machines Vocabulary Part I: General”, published by the International Organizatio
13、n for Standardization (ISO). This glossary of terms has been prepared in three Parts, the other Parts being as follows. Part 2: Compressors; Part 3: Pneumatic tools and machines 1) . Terminology and conventions. The text of the International Standard has been approved as suitable for publication, wi
14、thout deviation, as a British Standard. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Sta
15、ndard”. At present there are no corresponding British Standards for the following International Standards referred to in the annex for information purposes: ISO 3529 2) ISO 4006:1977 (Available from BSI Sales Department, 101 Pentonville Road, London N1 9ND) A British Standard does not purport to inc
16、lude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, page
17、si andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) In course of preparation. Cross-references International Standard Cor
18、responding British Standard ISO/R 31-I, ISO/R 31-II, ISO/R 31-III and ISO/R 31-IV and ISO 31-VIII BS 1991 Letter symbols, signs and abbreviations Part 1:1976 General a (Related) ISO 3534:1977 BS 5532:1978 Statistics Vocabulary and symbols (Identical) a Attention is drawn to footnote 1) in the Annex.
19、 ISO 31-I, ISO 31-II, ISO 31-III and ISO 31-IV have now been published; the identical British Standards currently in course of preparation are BS 5775-1, BS 5775-2, BS 5775-3 and BS 5775-4. 2) At present at the stage of draft.BS5791-1:1979 BSI 10-1999 1 Scope and field of application This Internatio
20、nal Standard constitutes the first part of a vocabulary relating to compressors, pneumatic tools and machines. It deals with basic concepts, symbols and units. Part II deals with compressors. Part III 3)deals with pneumatic tools and machines. 1 Pressures 1.1 atmospheric pressure: The absolute press
21、ure of the atmosphere as measured at the place under consideration. 1.2 gauge pressure: The pressure as measured with reference to atmospheric pressure. 1.3 absolute pressure: The pressure with reference to absolute zero, i.e. with reference to an absolute vacuum. It equals the algebraic sum of atmo
22、spheric pressure and gauge pressure (static pressure or total pressure). 1.4 static pressure: The pressure as measured in a fluid in such conditions that no effect on measurement is produced by the fluid velocity. 1.5 dynamic pressure: That increase of pressure which would result if the energy of th
23、e flow velocity in gas or air flowing at uniform velocity were converted to pressure completely and without any losses, i.e. isentropically. The pressure is equal to the product pc 2 /2, where is the fluid density and c is the flow velocity. 1.6 total pressure: The sum of the static and dynamic pres
24、sures. It designates the fluid condition at which the flow energy of the fluid is converted into pressure without any losses. In a stationary body of fluid, the static pressure and total pressure are numerically equal. 1.7 critical pressure: The limiting pressure above which no discontinuity is obse
25、rved between the gas phase and the liquid phase, whatever the temperature. 1.8 reduced pressure: The quotient of the absolute pressure and the absolute critical pressure. 1.9 compressibility factor Z: A dimensionless factor designating the actual gas state from its perfect state. It is expressed by
26、the formula: where 2 Temperatures 2.1 static temperature: The temperature as measured in a fluid in such conditions that no effect on measurement is produced by the fluid velocity. 2.2 dynamic temperature: That increase of temperature which would result if the energy of the fluid velocity in gas or
27、air at uniform velocity were converted to calorific energy completely and without any losses, i.e. isentropically. 2.3 total temperature: The sum of the static and dynamic temperatures. It designates the fluid condition at which the flow energy of the fluid is converted into calorific energy without
28、 any losses. In a stationary body of fluid, the static temperature and total temperature are numerically equal. 2.4 critical temperature: The limiting temperature above which no discontinuity is observed between the gas phase and the liquid phase, whatever the pressure. 2.5 reduced temperature: The
29、ratio of the thermodynamic temperature of the fluid to its critical thermodynamic temperature. 3) In preparation. p is the pressure; V m is the molar volume; R is the molar gas constant; T is the thermodynamic temperature. Z pV m RT - =BS5791-1:1979 2 BSI 10-1999 Table 1 Symbols and units Reference
30、number in ISO/R 31 a Reference number in ISO 3857 b Symbol SI unit Other practical units Quantity Dimensions c 1-4.1 area A L 2 m 2 mm 2 1-5.1 volume V L 3 m 3 l, ml, mm 3 3-4.1 mass specific volume v M 1 L 3 m 3 /kg 8-6.1 molar volume V m L 3 N 1 m 3 /mol 1-6.1 time t T s h, min, ms 1-10.1 velocity
31、 c LT 1 m/s km/h 1-10.1 peripheral velocity u LT 1 m/s 1-8.1 angular velocity T 1 rad/s 2-3.2 rotational n T 1 s 1 min 1 frequency 3-1.1 mass m M kg t, g, mg 3-2.1 mass density ML 3 kg/m 3 kg/l 4-2.1 Celsus temperature () C 4-1.1 thermodynamic T () K temperature 3-11.1 pressure p ML 1 T 2 Pa MPa, ba
32、r, kPa, mbar 3-22.1 work W ML 2 T 2 J MJ, kJ, kWh 3-23.1 power P ML 2 T 3 W Mw, kW II-6 mass specific energy W m L 2 T 2 J/kg kJ/kg II-6 volume specific energy W v ML 1 T 2 J/m 3 J/l, KWh/m 3 mass rate of flow q m MT 1 kg/s kg/h II-3 volume rate of flow q v L 3 T 1 m 3 /s m 3 /h, m 3 /min, l/s, ml/s
33、 II-1.4 relative clearance volume e pure number II-5.2 exponent for polytropic process in p.V diagram n pure number 8-33.1 molar gas constant R ML 2 T 2 () 1 N 1 J/(Kmol) kJ/(Kmol) I-1.9 compressibility factor Z pure number II-7 efficiency pure number 12-6 II-1.10 tip Math number Ma U pure number II
34、-4.6 pressure coefficient pure number II-4.7 II-7.5 volumetric coefficient pure number II-1.5 outside diameter of the impeller D L m mm II-1.5 hub diameter of the impeller d L m mm a See Annex. b The roman numbers I and II refer to the relevant parts of this International Standard. c M massL lengthT
35、 time() temperatureN quantity of matterBS5791-1:1979 BSI 10-1999 3 Table 2 Letters used as symbols Symbol Quantity SI unit A area m 2 c velocity m/s d hub diameter of the impeller m D outside diameter of the impeller m e relative clearance volume pure number m mass kg Ma U tip Mach number pure numbe
36、r n exponent for polytropic process in p.V diagram pure number n rotational frequency s 1 p pressure Pa P power W q m mass rate of flow kg/s q v volume rate of flow m 3 /s R molar gas constant J/(Kmol) t time s T thermodynamic temperature K u peripheral velocity m/s v mass specific volume m 3 /kg V
37、volume m 3 V m molar volume m 3 /mol W work J W m mass specific energy J/kg W v volume specific energy J/m 3 Z compressibility factor pure number efficiency pure number Celsius temperature C mass density kg/m 3 volumetric coefficient pure number pressure coefficient pure number angular velocity rad/
38、sBS5791-1:1979 4 BSI 10-1999 Table 3 Letters and figures used as subscripts Symbol Meaning Observations 0 ambient condition 1 inlet indicates the quantities measured at the standard inlet point of the compressor 2 discharge indicates the quantities measured at the standard discharge point of the com
39、pressor a absolute ab absorbed ar shaft b atmospheric characterizes the atmospheric pressures and temperatures C contractual indicates the quantities specified in the contract cd condensate cr critical characterizes the critical pressures and temperatures d dynamic characterizes the dynamic pressure
40、s and temperatures e effective g overall i indicated in internal m mass characterizes the mass specific rates of flow, energies and volumes m molar characterizes the molar volumes me mechanical N normal pol polytropic characterizes a polytropic process r reduced characterizes the reduced pressures a
41、nd temperatures R read indicates the quantities read during the test or predetermined as test conditions s static S isentropic characterizes an isentropic process t total T isothermal characterizes an isothermal process th theoretical u useful U peripheral v volume characterizes the volume rates of
42、flow and energiesBS5791-1:1979 BSI 10-1999 5 Annex References ISO/R 31-I, ISO/R 31-II, ISO/R 31-III and ISO/R 31-IV 4) , and ISO 31-VIII. ISO 3529, Vacuum technology Vocabulary 5) . ISO 3534, Statistics Vocabulary and symbols. ISO 4006, Measurement of fluid flow-rate in closed conduits Vocabulary an
43、d symbols 5) . Vocabulary of legal metrology, OIML. 4) It should be noted that these first four parts of ISO/R 31 are currently being revised for publication as International Standards, and that consequently the reference numbers cited in the first column ofTable 1 are liable to amendment. 5) At pre
44、sent at the stage of draft.6 blankBS5791-1:1979 BSI 10-1999 Publications referred to See national foreword.BS 5791-1: 1979 ISO 3857-I: 1977 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It pres
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