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1、BRITISH STANDARD BS 1704:1985 ISO 1770:1981 Incorporating Amendment No. 1 Specification for Solid-stem general purpose thermometers UDC 536.512/.513 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 This British Standard, having b
2、een prepared under the direction of the Laboratory Apparatus Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 June 1985 BSI 01-2000 First published February 1951 First revision June 1985 The following BSI references relate to the work on this sta
3、ndard: Committee reference LBC/4 Draft for comment 79/54294 DC ISBN 0 580 14258 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Laboratory Apparatus Standards Committee (LBC/-) to Technical Committee LBC/4, upon which the following bod
4、ies were represented: British Laboratory Ware Association British Lampblown Scientific Glassware Manufacturers Association Ltd. British Medical Association Department of Health and Social Security Department of Trade and Industry (National Physical Laboratory) Institute of Petroleum Ministry of Defe
5、nce Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 BSI 01-2000i Contents Page Committees responsibleInside front cover National forewordii 0Introduction1 1Scope
6、and field of application1 2Reference1 3Temperature scale1 4Immersion1 5Glass1 6Liquid filling2 7Gas filling2 8Construction2 9Scale lines, immersion line and figuring2 10Accuracy2 11Inscriptions3 National appendix A Testing of British Standard thermometers7 Figure Examples of scale lines and figuring
7、6 Table 1 Requirements for solid-stem general purpose thermometers for measurements of lower accuracy4 Table 2 Requirements for solid-stem general purpose thermometers for measurements of higher accuracy5 Table 3 Uncertainty of test for certification of British Standard general purpose thermometers7
8、 Publication referred to8 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 ii BSI 01-2000 National foreword This British Standard has been prepared under the direction of the Laboratory Apparatus Standards Committee. This edition
9、 is identical with ISO 1770:1981 “Solid-stem general purpose thermometers” published by the International Organization for Standardization (ISO) and incorporates a change to clause 11 brought about by Amendment 1 to ISO 1770 issued in August 1983. This standard supersedes BS 1704:1951 which is withd
10、rawn. The principal differences between the 1951 edition and this edition include the introduction of a series of greater accuracy intended for possible testing by a national verification laboratory, the withdrawal of thermometers marked in Fahrenheit, and changes to the scale division, accuracy and
11、 line thickness. National appendix A gives details of testing of the thermometers J to W. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identi
12、cal with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring
13、to this standard, they should be read as “British Standard”. Cross-reference. The reference to ISO 386, which only appears in clause 0, is of an informative nature only and the lack at present of an equivalent British Standard therefore does not affect the validity of this standard. Additional infor
14、mation. Attention is drawn to the requirement for marking in clause 111). Certification. Attention is drawn to the certification facilities described on the inside back cover. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are re
15、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, pages i and ii, pages 1 to 8, an inside back cover and a back cover. This standard has
16、 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) Marking BS 1704:1985 on or in relation to a product is a claim by the manufacturer that the product has been manufactured to the requirements of th
17、e standard. The accuracy of such a claim is therefore solely the manufacturers responsibility. Enquiries as to the availability of third party certification to support such claims should be addressed to the Director, Quality Assurance Division, BSI, PO Box 375, Milton Keynes MK14 6LO for certificati
18、on marks administered by BSI or to the appropriate authority for other certification marks. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 BSI 01-20001 0 Introduction Although the thermometers covered by this International Stan
19、dard are not intended for use in any specific test method, the overall lengths of the series of higher accuracy are specified with a tolerance so as to provide a degree of interchangeability for any special apparatus into which the thermometers are incorporated. For ease of reference, each thermomet
20、er has been allocated a designation consisting of a single letter representing the range of the thermometer and the indication “TOTAL” or, for example, “75” relating to the intended immersion. Some of the thermometers described in the scope and field of application of this International Standard, an
21、d which are in current use, are of a lower quality than those strictly covered in ISO 386. Accordingly, whilst this International Standard is based on the provisions of ISO 386, it does not align with those which recommend the distance between consecutive scale lines to be greater than 0,8 mm and th
22、e maximum error to be one scale division. In order to avoid increasing the cost of the thermometers, some of the dimensions recommended to be specified in ISO 386 have also been omitted. 1 Scope and field of application This International Standard specifies requirements for two series of inexpensive
23、 “commercial quality” liquid-in-glass thermometers of the solid-stem type suitable for general purpose use in industry, schools and laboratories when great accuracy of measurement is not required: a) a series designated A to H, in which nominal ranges and maximum overall lengths are specified but wh
24、ich may not be acceptable for testing by a national verification laboratory; b) a series designated J to W of greater accuracy than in a) and with specified ranges and a tolerance on overall length, which may be acceptable for testing by a national verification laboratory. The temperature range cove
25、red by each series is from 100 C to + 500 C. 2 Reference ISO 386, Liquid-in-glass laboratory thermometers Principles of design, construction and use. 3 Temperature scale The thermometers shall be graduated in accordance with the Celsius scale as defined in the current definition of the International
26、 Practical Temperature Scale (IPTS) adopted by the Confrence gnrale des poids et mesures, and in accordance with the International System of Units (SI). 4 Immersion 4.1 The thermometers shall be adjusted for use either at total immersion (i.e. the reading shall be correct when the thermometer is imm
27、ersed so that the top of the liquid column is in the same plane as, or no more than two scale divisions above, the surface of the medium the temperature of which is required to be measured), or for partial immersion, as required. 4.2 In the latter case, the preferred immersion is 75 1 mm, and the ad
28、justment of such a thermometer shall be carried out at the average emergent liquid column temperature detailed in Table 1 and Table 2. NOTE 1Adjustment at partial immersion is not permitted for the thermometers with a scale extending below 38 C, because of the large errors likely to be caused in a s
29、pirit-in-glass thermometer by variations in temperature around the emergent portion of the stem. NOTE 2For guidance on the determination of the emergent liquid column corrections to be applied when the thermometer is used in situations where the average emergent liquid column temperature differs fro
30、m that given in Table 1 and Table 2, see annex B.6 and B.7 of ISO 386. 5 Glass The thermometer bulb shall be made of suitable thermometric glass.2) The glass or glasses comprising the thermometer shall be selected and processed so that the finished thermometer shows the following characteristics. a)
31、 Stress in the glass of the bulb and capillary stem shall be reduced to a level sufficient to minimize the possibility of fracture due to thermal or mechanical shock. b) The bulb glass shall be stabilized by suitable heat treatment to ensure that the accuracy requirements of clause 10 are met. c) Th
32、e legibility of the reading shall not be impaired by devitrification or clouding. d) The meniscus or its image shall be distorted as little as possible by defects or impurities in the glass. 2) An International Standard (ISO 4795) dealing with glasses for thermometer bulbs is in preparation. License
33、d Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 2 BSI 01-2000 6 Liquid filling 6.1 Mercury shall be used as liquid filling except for thermometers with a scale extending below 38 C for which a filling of an organic liquid shall be used
34、 which will remain liquid throughout the temperature range under the pressures prevailing inside the thermometer. 6.2 The organic liquid used as the liquid filling should preferably be coloured by means of a light-fast dye which does not stain the glass. 6.3 The organic liquid used as the liquid fil
35、ling should preferably be toluene or an isomer or suitable mixture of isomers of pentane. 7 Gas filling Thermometers containing mercury as the liquid filling shall be filled with a dry inert gas above the liquid filling. The pressure of the gas shall be high enough to raise the boiling point of the
36、liquid sufficiently to minimize vaporization over the nominal range of the thermometer. 8 Construction 8.1 Shape The thermometers shall be straight. Their external cross-section should be approximately circular, but if required, an external lens-shaped deviation from the circular cross-section is pe
37、rmitted to facilitate reading. 8.2 Top finish The top of the thermometer shall be finished with a plain top, button top or glass ring. In all cases, the diameter of the top finish of the thermometer shall not exceed that of the stem. 8.3 Capillary tube The capillary tube should preferably incorporat
38、e an enamel back. The inside of the capillary tube shall be smooth in order to avoid possible sticking of the liquid filling. For the thermometers listed in Table 2, the cross-sectional area of the bore shall not show variations from the average greater than 10 %. 8.4 Expansion volume (safety chambe
39、r) 8.4.1 An expansion volume shall be provided at the top of the capillary tube. This volume may take the form either of an extension of the bore or of an expansion chamber. NOTEOverheating a thermometer beyond its upper nominal limit is liable to change the zero or other fiducial point of the therm
40、ometer, and a redetermination of this point will therefore become necessary if it takes place. 8.4.2 If an expansion chamber is incorporated, it shall, except when the stem is made from borosilicate glass, be pear-shaped with the hemisphere at the top. 8.5 Enlargement of bore There shall be at least
41、 10 mm of unchanged capillary between any enlargement and the nearest scale line or immersion line. 8.6 Dimensions The dimensions of the thermometers shall be as detailed in Table 1 and Table 2. The tolerance on the overall length of the thermometers of higher accuracy given in Table 2 shall be 10 m
42、m. The bulb diameter shall not exceed that of the stem. 9 Scale lines, immersion line and figuring 9.1 The nominal ranges, figuring and scale divisions of the thermometers shall be as detailed in Table 1 and Table 2. 9.2 The scale lines shall be clearly etched or otherwise durably marked and of unif
43、orm thickness not exceeding the values given in Table 1 and Table 2. The lines shall be at right angles to the axis of the thermometer. Typical schemes of graduation and figuring are shown in the Figure. 9.3 In the case of the thermometers listed in Table 1 with 0 C as the lower nominal limit or 100
44、 C as the upper nominal limit, the scale shall be extended by at least three divisions beyond each of these limits. In all other cases, the scales may also be suitably extended beyond the nominal limits. 9.4 On thermometers adjusted for partial immersion the immersion depth shall be indicated by a l
45、ine on the stem at the appropriate distance from the bottom of the bulb (see clause 4). This line shall be marked around the back of the thermometer and shall not cross the scale. 9.5 In the case of etched scales, the pigment filling shall remain in the scale lines, figures, inscriptions and immersi
46、on line under normal conditions of use. 10 Accuracy The instrument error for the thermometers shall not be greater than the values given in Table 1 and Table 2. NOTEIn the case of thermometers of ranges 0 to 360 C and 0 to 500 C, an appreciable error may develop after long exposure at temperatures i
47、n the upper part of the scale range. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 05:59:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1704:1985 BSI 01-20003 11 Inscriptions 11.1 The following inscriptions shall be durably and legibly marked on the thermometers: a) unit of temperature: a
48、bbreviation of the name Celsius, for example “C”, or the symbol “C”; b) the designation of the thermometer; c) for partial immersion thermometers, an indication of the immersion depth for which the thermometer is adjusted, for example “75 mm”. No inscription is required for total immersion thermomet
49、ers; d) vendors and/or makers name or readily identifiable mark; e) the number of this International Standard, i.e. ISO 1170, or the number of the corresponding national standard; f) identification of the bulb glass, preferably by means of a coloured stripe or stripes, or by an inscription on the thermometer; 11.2 In addition to 11.1 if the purchaser requires the thermometer to bear an identifying number, the following inscription shall also be durably and legibly marked on the thermometer: manufacturers identification or serial number, the last