1、BRITISH STANDARD BS 5471:1977 Incorporating Amendment No. 1 Specification for Thermometer for use with alcohol hydrometers UDC 536.512:531.756.3:542.3:661.722BS5471:1977 This British Standard, having been prepared under the directionof the Laboratory Apparatus Standards Committee,was published under
2、the authority of the Executive Board on 31 March1977 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference LBC/4 Draft for comment 76/54426 ISBN 0 580 09832 X Cooperating organizations The Laboratory Apparatus Standards Committee, under whose supervision t
3、his British Standard was prepared, consists of representatives from the following Government departments and scientific, industrial and consumer organizations: Agricultural Research Council Association for Science Education Association of Technical, Scientific and Managerial Staffs British Laborator
4、y Ware Association* British Lampblown Scientific Glassware Manufacturers Association Ltd.* British Pharmacopoeia Commission Chemical Industries Association* Chemical Society, Analytical Division Department of Health and Social Security* Department of Industry, Laboratory of The Government Chemist* D
5、epartment of Industry, National Physical Laboratory* Glass Manufacturers Federation Institute of Petroleum* Ministry of Defence* Pharmaceutical Society of Great Britain Scientific Instrument Manufacturers Association Society of Chemical Industry Society of Glass Technology Standardization of Tar Pro
6、ducts Tests Committee The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Medical Association Meteoro
7、logical Office Amendments issued since publication Amd. No. Date of issue Comments 2788 March 1979 Indicated by a sideline in the marginBS5471:1977 BSI 09-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Type, range and graduation interval 1 4
8、Temperature scale 1 5 Immersion 1 6 Glass 1 7 Liquid filling 1 8 Gas filling 1 9 Construction 1 10 Marking 2 11 Accuracy 3 12 Inscriptions 3 Appendix A List of approved NPL glasses 4 Appendix B Testing of British Standard thermometers 4 Table 1 Dimensions for thermometers for use with alcohol hydrom
9、eters 2 Table 2 Thermometric glasses approved by the National Physical Laboratory (1977) 4 Publications referred to 6BS5471:1977 ii BSI 09-1999 Foreword This British Standard was published under the authority of the Laboratory Apparatus Standards Committee following consultations between Government
10、departments, manufacturers, and users of alcohol hydrometers. It was prepared at the request of HM Customs and Excise in support of an intended statutory instrument to implement a Council Directive of the EEC 1) , and covers only the thermometer which is expected to be used in the UnitedKingdom. It
11、thus excludes enclosed-scale glass thermometers and thermometers with a graduation interval of0.1 C or0.2 C. The requirements of this British Standard align with those of two draft International Standards for thermometers, ISO/DIS 386 2)and ISO/DP6152 3)insofar as they were known at the time of prep
12、aration. The International Standards were in course of preparation by Sub-committee3, Thermometers, of ISO Technical Committee48, Laboratory glassware and related apparatus. Appendix A lists thermometric glasses approved by the National Physical Laboratory. Information on the testing of thermometers
13、 for use with alcohol hydrometers is given inAppendix B. Certification. Attention is drawn to the certification facilities described on the inside back cover of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are re
14、sponsible 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, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has bee
15、n updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) Council Directive of 27 July 1976, 76/765/EEC on the approximation of the laws of the Member States relating to alcoholometers and alcohol hydrometers.
16、 2) ISO386 was subsequently published in 1978 without significant technical changes to the text of DIS 386. 3) In course of preparation.BS5471:1977 BSI 09-1999 1 1 Scope This British Standard specifies requirements for a solid-stem mercury-in-glass thermometer for use with alcohol hydrometers comply
17、ing with the requirements of BS5470. 2 References The titles of the publications referred to in this standard are given on the page 6. 3 Type, range and scale interval 3.1 The thermometer shall be of the solid-stem type. 3.2 The nominal range of the thermometer shall be from 5 C to+40 C. 3.3 The sma
18、llest scale division shall be0.5 C. 4 Temperature scale The thermometer shall be graduated in accordance with the Celsius scale as defined in the1968 definition of the International Practical Temperature Scale (IPTS-68) adopted by the Confrence Gnrale des Poids et Mesures, and in accordance with the
19、 International System of units (SI). 5 Immersion The thermometer shall be graduated for complete immersion,i.e. the entire thermometer being immersed in the sample. 6 Glass The thermometer shall be made of a suitable thermometric glass selected and processed so as to show the following characteristi
20、cs. 6.1 The bulb shall be made of an approved thermometric glass (seeAppendix A) and shall be stabilized by suitable heat treatment to ensure that the accuracy requirements of11.1 and11.2 can be met. 6.2 The stem shall be made of a lead glass or other suitable glass with a white enamel back. 6.3 Str
21、ess in the glass of the bulb and stem shall be reduced to a level sufficient to minimize the possibility of fracture due to thermal or mechanical shock. 6.4 The legibility of the reading shall not be impaired by devitrification or clouding. 6.5 The image of the meniscus shall be distorted as little
22、as possible by defects or impurities in the glass. 7 Liquid filling The liquid filling shall be mercury free from any contamination likely to interfere with the proper functioning of the thermometer. 8 Gas filling The space above the mercury shall be filled with a dry inert gas. 9 Construction 9.1 T
23、he thermometer shall be straight and its external cross section shall be approximately circular. 9.2 The top of the thermometer shall preferably be plain rounded, or finished with a glass ring or button as requested by the user. 9.3 The inside of the capillary tube shall be smooth, and the cross-sec
24、tional area of the bore shall not show variations from the average greater than10%. 9.4 The bore of the capillary tube shall be of sufficient diameter to ensure that the thermometer complies with10.1. 9.5 There shall be an expansion chamber at the top of the capillary tube consisting of a pear-shape
25、d chamber with the hemisphere at the top. The volume above the scale shall be such that the thermometer will withstand exposure to a temperature of80 C without damage.BS5471:1977 2 BSI 09-1999 9.6 Dimensions of the thermometer shall be as given inTable 1. Table 1 Dimensions for thermometer for use w
26、ith alcohol hydrometers 10 Marking 10.1 General. The thermometer shall be such that its indication can easily be read through the wall of a glass jar containing the sample. NOTEThe bore, scale lines, and figuring often have to be viewed under the poor lighting conditions commonly encountered in the
27、field use of alcohol hydrometers. 10.2 Scale lines and figuring 10.2.1 The pattern of graduation shall be as follows. a) Every tenth scale line shall be a long line. b) There shall be four medium lines equally spaced between two consecutive long lines. c) There shall be one short line between two co
28、nsecutive medium lines or between consecutive medium and long lines. 10.2.2 Every tenth scale line shall be fully figured. 10.2.3 The scale lines shall be clearly etched or otherwise durably marked and of a uniform thickness, which shall not be less than0.12mm nor exceed0.20mm. The lines shall be at
29、 right angles to the axis of the thermometer. 10.2.4 When the thermometer is held in a vertical position and viewed from the front, the left hand ends of all the scale lines shall lie on an imaginary vertical line. When the thermometer is viewed in such a position that the right-hand end of the shor
30、test scale lines align with the left-hand side of the bore, the medium and long lines shall extend across the bore towards the right. The figures shall be placed slightly to the right of the line in such a way that an extension of the line to which they refer would bisect them. The figures shall be
31、upright when the thermometer is held vertically and shall be so chosen to ensure that the thermometer complies with10.1. When the mercury column is viewed in this position at least the right-hand ends of the shortest scale lines and the figures shall be in full view. The minimum length of the shorte
32、st scale lines shall be1.5mm; the length of the medium scale lines shall be nominally1.5times the length of the short lines, and the length of the long scale lines shall be nominally2.5times the length of the short scale lines. The scale lines and figures shall be so positioned that the enamel backi
33、ng in the stem provides a background to the mercury column when it is seen just beyond the right-hand end of the short scale lines. 10.2.5 Each end of the scale shall be extended by2 or4 divisions beyond the nominal scale limits. 10.3 Pigment filling. The pigment filling in the etched scale lines, f
34、iguring and inscriptions shall be black and shall withstand immersion in all mixtures of ethanol and water for at least24h. Dimension mm Total length max. min. 250 245 Distance from top of bulb (shoulder) to lower nominallimit of scale min. 20 Length of scale (between nominal limits) min. 130 Diamet
35、er of stem 5.5 to 8.0 External diameter of bulb min. max. 5 not greater than that of stem Length of bulb to shoulder min. 15 Distance from top of bulb funnel to lowest scale line min. 13 Distance from highest scale line to bottom of expansion chamber min. 10BS5471:1977 BSI 09-1999 3 11 Accuracy 11.1
36、 Instrument error. The maximum permissible instrument error shall be 0.2 C when the thermometer is vertical and completely immersed in the sample. 11.2 Interval error. The maximum permissible difference between the errors at any two points which are50 divisions apart shall not be more than0.4 C. 12
37、Inscriptions The following inscriptions shall be durably and legibly marked on the thermometer. a) Temperature scale indication. The official symbol: “ C”. An abbreviation of the name Celsius, e.g.“C”is also permitted. b) Immersion. “Complete” or suitable abbreviation. c) Gas filling, e.g. “Nitrogen
38、 filled”, or suitable abbreviation. d) Bulb glass. The glass from which the bulb is made should preferably be identified by means of a coloured stripe or stripes, or by an inscription on the thermometer (seeAppendix A). e) Manufacturers identification number. The last two digits of the number shall
39、indicate the year of manufacture. f) Makers name or readily identifiable mark. g) The number of this British Standard, i.e. BS5471. h) The designation, i.e. AH/0.5/ 5/+ 40.BS5471:1977 4 BSI 09-1999 Appendix A List of approved NPL glasses Table 2 Thermometric glasses approved by the National Physical
40、 Laboratory (1977) Appendix B Testing of British Standard thermometers The British Standards Institution at its Hemel Hempstead Centre is prepared to examine thermometers for compliance with the requirements of this British Standard. Satisfactory thermometers are marked with the letters BST and the
41、year of test. Testing arrangements and particulars of fees can be obtained on application to the Director, British Standards Institution, Maylands Avenue, Hemel Hempstead, Herts HP24SQ. It is desirable that thermometers be retested at intervals not exceeding five years, or more frequently if determi
42、nations at a reference point indicate that retest is required. A change of one or two divisions does not necessarily indicate the need for a complete retest as this may be due to a normal change in the volume of the bulb and may be allowed for by applying a correction, equal to the zero change, thro
43、ughout the scale. Glass Identification stripe(s) or approved abbreviation Normal maximum working temperature C Normal glass, made by Whitefriars Glass Limited Single blue stripe 350 Normal glass, Dial, made by Plowden and ThompsonLimited Double blue stripe 350 Normal glass, Schott-N 16, made by Jena
44、er Glaswerk Schott and Genossen, Mainz Single red stripe 350 Normal glass, 7560, made by Corning Glass Company CN 350 Corning borosilicate glass, made by Corning Glass Company CB 450 Thermometric glass, Schott-2954, made by Jenaer Glaswerk Schott and Genossen, Mainz Single black stripe 460 Borosilic
45、ate glass, made by Whitefriars Glass Limited Single white stripe 460 Corning glass, 1720, made by Corning Glass Company C 1720 600 Schott-Supermax R 8409, made by Jenaer Glaswerk Schott and Genossen, Mainz SPX 8409 600 NOTEThe maximum temperatures given in the last column of the table are a guide to
46、 normal practice. The performance of a thermometer depends greatly on the stabilizing heat treatment which it has been given during manufacture, and a well-made thermometer of “normal glass” may be quite satisfactory for many purposes at temperatures as high as400 C. On the other hand, for the best
47、accuracy it may be preferred to use one of the borosilicate glasses for temperatures lower than350 C. In general, the lower the maximum temperature of use in relation to the approved temperature of the glass, the better will be the “stability of zero” of the thermometer.5 blankBS5471:1977 BSI 09-199
48、9 6 Publications referred to BS 5470, Glass alcohol hydrometers not incorporating a thermometer. ISO 386, Liquid-in-glass laboratory thermometers Principles of design, construction and use. ISO/DP 6152, Thermometers for use with glass alcoholometers and alcohol hydrometers 4) . 4) In course of prepa
49、ration.BS5471:1977 BSI 09-1999 BSI Certification Trade Mark The Kitemark The Kitemark is a registered certification trade mark of the British Standards Institution. A licence to use the Kitemark on or in relation to a product will be granted to any manufacturer or producer who demonstrates that he can and will be able consistently to make that product to a specified British Standard. His capability of doing so is initially assessed by inspection of his production process, quality control organization and test facilities, and by independent t
