1、Pressure gauges - Vocabulary The European Standard EN 472 : 1994 has the status of a British Standard BS EN 472 : 1995 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect
2、on 15 September 1995 0 BSI 1995 Amd. No. Date The following BSI references relate to the work on this standard: Committee reference GEL/65 Draft for comment 91124810 DC ISBN O O80 24628 O Qxt affected Committees responsible for this British Standard The preparation of this British Standard was entru
3、sted to Technical Committee GEL/65, Measurement and control, upon which the following bodies were represented: British Coal Corporation British Gas plc British Nuclear Fuels plc Electrical Contractors Association Electricity Association Energy Industries Council GAMBICA (BEAMA Ltd.) Health and Safet
4、y Executive Institution of Gas Engineers The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Compressed Air Society British Compressed Gases Association British Fluid Power Association British Pressure Gauge Manufacturers Association
5、Department of Trade and Industry (National Engineering Laboratory) CEN ENa472 94 3404589 0305096 304 = BS EN 472 : 1995 Contents Page Committees responsible Inside front cover National foreword 11 Foreword 2 lkxt of EN 472 3 i National foreword This British Standard has been prepared by Technical Co
6、mmittee GEL/65 and is the English language version of EN 472 : 1994, Pressure gauges - Vocabulary published by the European Committee for Standardization (CEN). No British Standard is superseded. Compliance with a British Standard does not of itself confer immunity from legal obligations. ii CEN ENa
7、472 94 3404589 0105098 T87 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 472 October 1994 UDC 681.2.084.83: OU 1.4 Descriptors: Measuring instruments, manometers, vocabulary English version Pressure gauges - Vocabulary Manomtres - Vocabulaire Druckmegerte - Begriffe This European Standard was
8、 approved by CEN on 1994-10-19. CEN memberc are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationa
9、l standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notif
10、ied to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom
11、. GEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1994 Copyright reserved to CEN members Ref, No. EN 472 : 1994 E CEN ENM472 94 page 2 EN 472 : 1994 Foreword This European Standard has
12、 been prepared by Rchnical Committee CEN/TC 141, Pressure gauges, of which the secretariat is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 1995, and conflicting national st
13、andards shall be withdrawn at the latest by April 1995. In accordance with the CENICENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norwa
14、y, Portugal, Spain, Sweden, Switzerland and United Kingdom. Contents Foreword O Introduction 1 Scope 2 Definitions relating to pressure 3 Definitions relating to pressure 4 Definitions relating to the Index gauges gauge components characteristics Page 2 3 3 5 4 8 10 CEN EN*472 94 3404589 OL05LOO 465
15、 = O Introduction In the preparation of this international standard, the following two principles have been followed as far as possible: - to standardize suitable terms without perpetuating unsuitable terms merely because they have been used in the past; - to discard any term which is used with diff
16、erent meanings and to replace it by a term which has an unequivocal meaning. 1 Scope This European Standard defines the fundamental and general terms to be used for pressure gauges. 2 Definitions relating to pressure gauges 2.1 indicating pressure gauge A measuring instrument which displays the valu
17、e of the applied pressure by means of a pointer relative to a scale. 2.2 indicating pressure gauges with an elastic measuring element Instrument in which the mechanical measuring sequence directly transmits the elastic deformation of the sensing element to the indicating device, consisting of a poin
18、ter and a graduated scale. 2.3 pressure gauge An indicator of the applied (gauge) pressure with respect to the atmospheric pressure. 2.4 vacuum gauge An indicator of the applied (gauge) vacuum with respect to the atmospheric pressure. 2.5 combined pressure and vacuum gauge A combined indicator of th
19、e applied (gauge) pressure or vacuum with respect to the atmospheric pressure. 2.6 absolute pressure gauge An indicator of absolute pressure, i.e. pressure relative to a complete vacuum. NOTE. This description therefore does not apply to pressure gauges graduated in absolute pressure units, the indi
20、cations of which are influenced by variations of atmospheric pressure. 2.7 differential pressure gauge A pressure gauge used to measure the difference between two applied pressure andlor vacuum values, the metallic pressure-responsive element(s) of which drive(s) one pointer. 2.8 duplex pressure gau
21、ge A pressure gauge used to measure two applied pressure andlor vacuum values, by means of two hge 3 EN 472 : 1994 separate pressure-responsive elements in one case, each of which drives its own pointer. 2.9 control pressure gauge A pressure gauge fitted with one or more switches which open or close
22、 one or more control circuits depending on the pointer position. 2.10 edgewise pressure gauge A pressure gauge with a rectangular dial for flush mounting in a panel or a control board, where the pivotal axis of the pointer lies in a plane parallel to the plane of the panel or control board. 2.11 liq
23、uid filled pressure gauge A pressure gauge, the case of which is filled with a liquid. 2.12 safety pattern gauge A gauge incorporating safety features and particularly suitable for use with high pressure gases and steam. 3 Definitions relating to pressure gauge components 3.1 pressure-responsive ele
24、ment An elastic element which undergoes deformations under the effect of pressure variations. It may be a Bourdon tube, diaphragm, diaphragm capsule, bellows or other type of element. 3.1.1 Bourdon tube A type of spiral pressure-responsive element where a tube with a non-circular cross-section is be
25、nt into a circular or coiled shape. Under the effect of the internally applied pressure the tube tends to straighten. The deflection induced is proportional to the pressure applied. 3.1.2 diaphragm A type of pressure-responsive element usually in the form of a concentrically corrugated membrane wher
26、e the pressure applied causes the diaphragm to deflect in proportion to the pressure. 3.1.3 capsule A type of pressure-responsive element comprising of two diaphragms suitably shaped and joint pressure-tight around their circumference. The pressure commonly acts on the interior of the capsule and th
27、e expansion generated thus is proportional to the pressure. 3.1.4 bellows A type of pressure-responsive element in the form of a thin-walled convoluted tube. The change in its length is proportional to the pressure. CEN ENx472 94 3404589 OlO5lOl 3Tl W Page 4 EN 472 : -1994 3.2 movement An assembly b
28、y means of which the deformations of the pressure-responsive element are transformed and enlarged into an angular variation. 3.3 pressure element assembly The assembly of all the pieces coming into contact with the fluid whose pressure is measured. 3.4 connection The part by which the pressure gauge
29、 can be coupled to the pressure tapping of the plant, pipework or equipment. 3.4.1 shank The part of the gauge that includes the screwed connection, the spanner flats, square or hexagon, the spigot, and the inlet orifice. 3.4.2 screwed connection The threaded portion of the shank. 3.5 pointer The in
30、dex, the position of which, in relation to the scale, indicates the value of the measured pressure. 3.5.1 adjustable pointer A pointer with an adjustable device for zero correction. 3.5.2 maximum pointer A secondary pointer driven by the pointer which stays at the maximum value reached by the latter
31、. 3.5.3 pointer stop A screw, stud, or other projection, fitted to limit the travel of the pointer. NOTE. It is not the function of a pointer stop to act as an overload stop. 3.6 adjustable mark A moving index operated from the outside and not driven by the indicating pointer, used to place a refere
32、nce mark on the dial. 3.7 case The casing which contains the pressure-responsive element, parts of the pressure element assembly and the movement. It may also include a safety device. The front face of the case may be circular, square or rectangular. 3.8 blow-out device A safety device incorporated
33、in the case or back plate to permit the rapid and safe dissipation of internal pressure in the event of a leakage or burst in the pressure responsive element. 3.8.1 blow-out back A safety device incorporating the greater part of the back of the case. 3.8.2 baffle wall A barrier between the pressure
34、responsive element and the dial, so disposed that, in the event of a leakage or burst in the pressure responsive element, the blast would be dissipated away from the front. 3.8.3 removable back plate A plate at the back of the case, that is removable for the purpose of giving access to the interior.
35、 3.9 flange The circular, square or rectangular part, removable or fixed, projecting from the case, on which the latter is mounted. 3.10 window The transparent front intended for protection of the pointer, dial and control devices, if any. 3.11 bezel ring The part which retains the window on the cas
36、e. 3.12 clamp The part used for mounting clamp fixing pressure gauges on panel boards. 3.13 spacer The distance piece, ring, or collar separating the window from the dial. 3.14 dial That part of an indicating device, fixed or moving, which carries the scale or scales. 3.15 scale (of an indicating de
37、vice) An ordered set of scale marks, together with any associated numbering, forming a part of an indicating device. 3.15.1 scale length For a given scale, the length of the line between the first and the last scale marks and passing through the centres of ail the shortest scale marks. 3.15.2 scale
38、range For a given scale, the set of scale values between the extreme scale marks. NOTE. The scale range is expressed in the units marked on the scale, regardless of the units of the applied pressure and is normally stated in terms of its lower and upper limits, for example O bar to 100 bar. 3.15.3 s
39、cale division The part of a scale between any two successive scale marks. 3.15.4 scale spacing The distance between any two successive scale marks measured along the same line as the scale length. NOTE. The line may be real or imaginary, curved or straight. CER EN*472 94 m 3404589 Oit05102 238 m NOT
40、E. Scale spacing is expressed in units of length, regardless of the units of the applied pressure or the units marked on the scale. 3.15.5 scale numbering The set of numbers, associated with scale marks, which correspond to the set of values of the applied pressure defined by the scale marks. 3.16 a
41、djustment Operation of bringing a pressure gauge into a state of performance suitable for its use. 3.17 user adjustment The operation intended to bring a pressure gauge into a state of performance and freedom from bias suitable for its use, employing only the means at the disposal of the user. 4 Def
42、initions relating to the characteristics 4.1 nominal size A conventional alpha-numerical designation relating to the size of the pressure gauge. 4.2 nominal range For each scale range, the set of indicated values of the applied pressure for which a pressure gauge gives values within that scale range
43、. NOTE. The nominal range is expressed in units of the applied pressure regardless of the units marked on the scale, and is normally stated in terms of its lower and upper limits, for example - 200 mbar to + 400 mbar. 4.3 span The modulus of the difference between the two limits of a nominal range o
44、f a pressure gauge. EXAMPLE Nominal range -200 mbar to +400 mbar: span 600 mbar. Page 5 EN 472: 1994 4.4 specified measuring range The set of values of an applied pressure for which the error of a pressure gauge is intended to lie within specified limits. 4.5 accuracy class A class of pressure gauge
45、 which meets certain metrological requirements that are intended to keep errors within specified limits. NOTE. An accuracy class is usually denoted by a number adopted by convention and called the class index. 4.6 limits of permissible error The extreme values of an error permitted by specifications
46、, regulations etc. for a given pressure gauge. 4.7 error (of indication) of a pressure gauge The indication of a pressure gauge minus the true value of the applied pressure. 4.8 repeatability of a pressure gauge The ability of a pressure gauge to give, under defined conditions of use, closely simila
47、r responses for repeated applications of the same stimulus. NOTE. The defined conditions of use are usually as follows: - repetition over a short period of time; - use at the same location under constant ambient conditions; - reduction to a minimum of the variations due to the observer. 4.9 hysteres
48、is The property of a pressure gauge whereby its response to a given stimulus depends on the sequence of preceding stimuli. NOTE. Although hysteresis is normally considered in relation to the applied pressure, it may also be considered in relation to influence quantities. CEN EN*472 94 3404589 010510
49、3 174 Page 6 EN 472: 1994 Index A absolute pressure gauge 2.6 accuracy class 4.6 adjustable mark 3.6 adjustable pointer 3.5. I adjustment 3.16 B baffle wall 3.8.2 bellows 3.1.4 bezel ring 3.11 blow-out back 3.2.1 blow-out device 3.8 Bourdon tube 3.1.1 C capsule 3.1.3 case 3.7 clamp 3.12 combined pressure and vacuum gauge 3.5 connection 3.4 control pressure gauge 2.9 R removable back plate 3.8.2 repeatability of a pressure gauge 4.8 5 safety pattern gauge 2.12 scale (of an indicating device) 3.15 scale division 3.15.3 scale length 3.15.1 scale numbering 3.15.5 scale range 3.15
