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1、INTERlYATlONAL ORGANIZATION FOR STANDARDIZATION.WEK!SH4POLIHAII OPCAHW3AUMR IlO CTAHLIAPTM3AUWORGANlSATlON INTERNATIONALE DE NORMALISATION Enclosed-scale calorimeter thermometers Thermometres pour CalorimPtres $ tkhalle pro these documents are now in the process of being transformed into Internation
2、al Standards. As part of this process, Technical Committee ISO/TC 48 has reviewed IS0 Recommendation R 652 and found it technically suitable for transformation. International Standard IS0 652 therefore replaces IS0 Recommendation R 6521968 to which it is technically identical. IS0 Recommendation R 6
3、52 was approved by the Member Bodies of the following countries : Australia Austria Belgium Brazil Bulgaria Canada Chile Colombia Czechoslovakia Egypt, Arab Rep. of France Greece Hungary India Ireland Italy Japan Korea Rep. of Netherlands New Zealand Poland South Africa, Rep. of Spain Switzerland Tu
4、rkey United Kingdom U.S.A. Yugoslavia The Member Body of the following country expressed disapproval of the Recommendation on technical grounds : Germany No Member Body disapproved the transformation of ISO/R 652 into an International Standard. 0 International Organization for Standardization, 1975
5、l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 08:02:38 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD
6、 IS0 652-1975 (E) Enclosed-scale calorimeter thermometers 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies requirements for a series of short-range enclosed-scale thermometers for use in bomb calorimetry and for other purposes where an accurate measurement of a change of temper
7、ature is required. The thermometers are not provided with auxiliary scales at 0 “C and are therefore not suited to the absolute measurement of temperature (which is not normally required in calorimetry), unless they are checked against a standard thermometer immediately before use. 2 TYPE OF THERMOM
8、ETER The thermometers shall be of the mercury-in-glass enclosed-scale type. 3 TEMPERATURE SCALE The thermometers shall be graduated in accordance with the Celsius scale as defined in the current definition of the International Practical Scale of Temperature, adopted by the Conference Generale des Po
9、ids et Mesures. 4 IMMERSION The thermometers should preferably be calibrated for use at total immersion (i.e. the reading is taken when the thermometer is vertical and immersed at least to the end of the liquid column in the medium whose temperature is required to be measured), but calibration for u
10、se at partial immersion is permitted at the request of the user. On partial immersion thermometers, a line shall be etched at least halfway round the sheath of the thermometer, at the level to which it is intended to be immersed, which should preferably be the junction of the “saddle” and the sheath
11、 (marked E in figure 1 j. 5 GLASS The glass shall be selected and processed so that the finished thermometer shows the following characteristics : 5.1 Stress in the glass shall be reduced to a level sufficient to minimize the possibility of fracture due to thermal or mechanical shock. 5.2 The correc
12、tion of the thermometer reading at the lowest temperature of the nominal range shall not change Datum line Saddle E (immersion level) Dimensions in millimetres 15 max. ,I 1 max. FIGURE 1 - Enclosed-scale calorimeter thermometer 1 Copyright International Organization for Standardization Provided by I
13、HS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 08:02:38 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO652-1975 (E) by more than 0.02 C immediately after the thermometer has been heated for 15 min at a temperature 30
14、C higher than the lowest temperature and allowed to cool naturally in air. 5.3 The legibility of the reading shall not be impaired by devitrification or clouding. 5,4 The meniscus shall be distorted as little as possible by defects or impurities in the glass. 6 GAS FILLING Above tke mercury, thermom
15、eters may be either vacuous or gas-filled; in the latter case, only a dry, inert gas shall be used. The indication of a gas-filled thermometer, when the meniscus is at the top of the scale, shall not change by more than 0,Ol C, when the temperature of the gas above the mercury is changed by 30 C. NO
16、TE - It is generally possible for this requirement to be satisfied if the internal gas pressure does not exceed 0,5 bar ), when the thermometer is registering its maximum temperature. 7 CONSTRUCTION 7.1 Shape The thermometers shall be straight and their external cross-section approximately circular.
17、 7.2 Top finish The top of the sheath shall be sealed by fusing and shall be covered by a metal cap. 7.3 Strip bearing the scale The strip bearing the scale shall be of a material suitable to the temperature to be measured and compatible with the method of fixing the strip. It shall be placed tightl
18、y against the capillary tube inside the sheath and shall be firmly and securely fastened at the top of the thermometer. A suitable method of fixing is by fusing a glass tube or rod to the sheath and to the upper end of the strip bearing the scale; the lower end of the strip shall be freely held in a
19、 suitable glass saddle. Alternatively, it shall be fixed inside the sheath in any other suitable manner that allows for differential expansion. 7.4 Capillary tube The inside of the capillary tube shall be smooth. The cross-sectional area of the bore shall not show variations from the average greater
20、 than 5 %, and the bore shall be wide enough to ensure that, without tapping, jumping of the meniscus does not exceed one half of the graduation interval, when the temperature is rising at a uniform rate not exceeding 0,05 C per minute. In the case of thermometers calibrated for use at partial immer
21、sion, the volume of mercury contained in the capillary tube between the immersion line and the lowest figured graduation line shall not exceed the equivalent of 2 C. 7.5 Expansion chamber (safety chamber) The capillary tube shall have an enlargement at the top, of sufficient size to allow heating of
22、 the thermometer to 60 C (70 C in the case of thermometers ECal/0,01/42 and ECal/0,01/451. This expansion chamber shall be pear-shaped, with the hemisphere at the top. It shall be so shaped that the meniscus remains in the narrow portion at temperatures up to 40 OC. 7.6 Contraction chamber A contrac
23、tion chamber shall be provided so that the mercury does not recede into the bulb at 0 “C. It shall be elongated and as narrow as possible. 7.7 Enlargement of the bore No enlargement of the bore shall be so located as to produce a variation in the cross-section of the capillary tube in the scale port
24、ion greater than that permitted in 7.4. 7.8 Dimensions The dimensions of the,thermometers shall be as given in table 1 and figure 1. TABLE 1 - Dimensions (see also figure 1) Dimensions in millimetres Total length Distance from bottom of bulb to top of contraction chamber Distance from bottom of bulb
25、 to lower nominal limit of scale Length of main scale (nominal limits) Distance from upper nominal limit of scale to top of ther- mometer Diameter of sheath External diameter of bulb and adjoining portion of stem Length of bulb to shoulder 760 max. 110 max. 280 to 300 300 min. 70 min. 15 max. 11 max
26、. 40 min. lj 1 bar=lOgPa 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 08:02:38 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 652 -1975 (E) 8
27、GRADUATION AND FIGURING 8.1 The scales and graduation interval of the ther- mometers shall be as given in table 2. TABLE 2 - Graduation Designation ECal/0,01/15 ECal/0,01/18 ECal/0,01/21 ECal/0,01/24 ECal/O,Ol I27 ECal/0,01/30 ECal/0,01/33 ECaV0,01/36 ECal/0,01/39 ECal/0,01/42 ECal/0.01/45 Graduatio
28、n interval I Nominal scale ranga “C I “C 0.01 9to15 0,Ol 12to 18 0,Ol 15 to 21 0.01 18to 24 0,Ol 21to 27 0,Ol 24 to 30 0,Ol 27to 33 0,Ol 30to 36 0,Ol 33to 39 0.01 36to42 0.01 39to45 8.2 The scale lines shall be clearly etched and of uniform thickness, which in no case shall exceed 0,05 mm. The lines
29、 shall lie in planes at right angles to the axis of the thermometer. 8.3 The arrangement and figuring of thescale lines shall be according to one of the types shown in figure 2. Each 0,l “C scale line shall be a long line, each 0,05 “C line shall have a length of two-thirds of the long lines, and ea
30、ch 0,Ol “C line shall have a length of one-third of the long lines. The figures shall be placed immediately above the line to which they refer. i 2 I I 2 I 2F F , 2 i 1 23 FIGURE 2 - Alternative typesof graduation end figuring 8.4 The scale of the thermometer shall be extended by ten divisions (i.e.
31、 0,l “C) beyond the nominal limits given in table 2. 8.5 The scale shall be figured at each 0,l “C division. Full figuring shall be provided at least at each division of 1 “C and more frequently, if required. 8.6 The pigment filling shall remain in the scale lines, figures and -inscriptions under co
32、nditions specified by agreement between purchaser and vendor. 8.7 Datum line At the right-hand side of the sheath, an indelible datum line shall be placed on a level with the lowest nominal scale line so that any displacement of the scale can easily be noticed. 9 ACCURACY 9.1 Scale error The scale e
33、rror, when the thermometer is under normal atmospheric pressure and when the emergent liquid column (in the case of a partial immersion thermometer) is at the prescribed temperature (see lob), shall not be greater than 0,l “c. 9.2 Interval error The absolute value of the algebraic difference between
34、 the errors at any two points which are not more than 50 divisions apart shall in no case be greater than 0,Ol C. 10 INSCRIPTIONS The following inscriptions shall be durably and legibly marked on the thermometer : a) Unit of temperature. Abbreviation of the name Celsius such as “C”, or symbol “ C”.
35、b) Immersion. On each thermometer, graduated for use at partial immersion, the immersion depth shall be indicated, and the emergent stem temperature for which the thermometer was calibrated shall be marked. c) Gas filling, if any; for example “nitrogen filled”, “vacuous” or a suitable abbreviation.
36、d) The bulb glass shall be identified, preferably by means of a coloured stripe or stripes, or by an inscription on the thermometer. e) Identification number (manufacturer s). f) Maker s and/or vendor s name or readily identifiable mark. g) The number of this International Standard, i.e. IS0 652. h)
37、 The designation allocated to the thermometer, for example ECal/0,01/15. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/28/2007 08:02:38 MDTNo reproduction or networking permitted without license from IHS -,-,-