1、BRITISH STANDARD BS 3231:1960 Specification for Thermographs (Bimetallic type) For air temperatures within the range 0 F to 140 F ( 20 C to 60 C)BS3231:1960 This British Standard, having been approved by the InstrumentIndustry StandardsCommittee and endorsed by theChairman oftheEngineeringDivisional
2、 Council, was published undertheauthorityof the GeneralCouncilon 17 March 1960 BSI 04-2000 The following BSI references relate to the work on this standard: Committee references INE/4 andINE/4/7 Draft for comment A(INE) 594 ISBN 0 580 34576 9 Co-operating organizations The Instrument Industry Standa
3、rds Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Scientific Workers British Ceramic Research Association British Clock and Watch Manufacturers A
4、ssociation British Electrical and Allied Industries Research Association British Electrical and Allied Manufacturers Association* British Industrial Measuring and Control Apparatus Manufacturers Association* British Iron and Steel Federation* British Nautical Instrument Trade Association British Rai
5、lways, The British Transport Commission British Scientific Instrument Research Association* Council of British Manufacturers of Petroleum Equipment Electricity Council, the Generating Board and the Area Boards in England and Wales* Engineering Equipment Users Association* Gauge and Tool Makers Assoc
6、iation Institute of Physics Institution of Chemical Engineers Institution of Electrical Engineers* Institution of Heating and Ventilating Engineers* Institution of Mechanical Engineers* Iron and Steel Institute Meteorological Office Ministry of Aviation* Ministry of Health Ministry of Housing and Lo
7、cal Government National Coal Board National Physical Laboratory (D.S.I.R.)* Oil Companies Materials Association* Radio Industry Council Scientific Instrument Manufacturers Association* Society of Instrument Technology Water-tube Boilermakers Association The Government departments and scientific and
8、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: Admiralty Air ministry British Coal Utilization Research Association Gas Council Ministry of Power Mini
9、stry of Works Physical Society Refrigerated Cargo Research Council Society of Chemical Industry War Office Individual manufacturers and users Amendments issued since publication Amd. No. Date CommentsBS3231:1960 BSI 04-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1
10、Scope 1 2 Materials 1 3 Design and construction 1 4 Temperature range 1 5 Accuracy 1 6 Lag (response) 1 7 Testing 1 8 Marking 2 9 Packaging 2 Appendix A General recommendations for despatch by manufacturer andsubsequent movement by customer from site to site 3BS3231:1960 ii BSI 04-2000 Foreword This
11、 standard makes reference to the following British Standards: BS 1133, Packaging code. BS 1986, Dimensional features of measuring and control instruments and panels for industrial purposes. BS 2548, Wood wool for general packaging purposes. BS 2770, Recommendations for the pictorial marking of handl
12、ing instructions for non-dangerous goods. This British Standard is one of a series prepared under the authority of the Instrument Industry Standards Committee at the request of the Temperature Measuring Instruments Sub-Committee of the Joint Equipment Standardization Committee. It is intended to cov
13、er Service requirements for a thermograph to record air temperatures, as well as the requirements for certain industrial and marine uses. NOTEWhere metric equivalents are stated, the figures in British units are to be regarded as the standard. The metric conversions are approximate. More accurate co
14、nversions should be based on the tables in BS 350, “Conversion factors and tables”. A British Standard does not purport to include 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 itse
15、lf confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendmen
16、t table on the inside front cover.BS3231:1960 BSI 04-2000 1 1 Scope This British Standard relates to thermographs of the bimetallic type, for general and marine use in obtaining a continuous record of air temperatures within the range 0 F to 140 F ( 20 C to 60 C). Such an instrument comprises a bime
17、tallic element, the response of which to temperature changes controls the movement of a pen, and a clock-driven drum carrying a chart on which the pen movement records against a temperature scale. A louvred screen may be used to protect the instrument during exposure, but the screen is not included
18、in this British Standard. If the instrument is to be used in conditions where vibration or violent movement is likely, shock absorbers or some other suitable device may be required to ensure that the specified accuracy is maintained. 2 Materials Wherever possible, the materials of construction shall
19、 be selected to avoid the possibility of electrolytic or atmospheric corrosion. The bimetallic element shall have received an appropriate stress-relieving treatment to ensure freedom from hysteresis. It shall also receive a suitable surface treatment to resist corrosion. 3 Design and construction Th
20、e thermograph shall preferably use one of the types of drum and chart described in BS 1986 1) . The recorder shall be provided with a suitable cover, with windows on at least the three sides which embrace the drum, or alternatively with a single window on the side on which the record is being traced
21、, so arranged as to provide free access for removal and replacement of charts. These windows shall be of permanently transparent, non-flammable material. A mechanism for withdrawing the pen from the chart shall also be fitted, operated from outside the cover. The bimetallic element may be of any con
22、venient form, such as a helix, a spiral or a cantilever, arranged to record low temperatures at the bottom of the chart. The position of the fixed end shall be adjustable, e.g. by a fine-adjustment screw and spring. The element shall be protected from damage by a guard of minimum heat capacity, so c
23、onstructed as to allow free passage of air. A clip shall be provided on the guard to carry a thermometer for air temperature measurement. If ink is used, provision shall be made for the safe storage of a container within the instrument. 4 Temperature range The nominal range of the instrument shall b
24、e either80 degF or 100 degF, within the extremes of0 F and 140 F. When specially ordered, provision may be made for recording down to 40 F. A zero adjustment of at least 25 per cent of the nominal range shall be provided, of such construction that a screwdriver or other tool can be used for fine con
25、trol. 5 Accuracy When the temperature is changed by 50 degF over any interval between 0 F and 140 F, the indicated difference in temperature shall not be in error by more than 1 degF when tested in accordance with Clause 7 a). 6 Lag (response) When any change in ambient temperature takes place, the
26、instrument shall record at least two-thirds of such change within 30 seconds when tested in accordance with Clause 7 b). 7 Testing a) Accuracy. The clock shall be removed to avoid damage and a metal strip bearing the appropriate scale substituted, the pen arm pressure on the strip being adjusted to
27、simulate pen/paper friction. The instrument shall then be tilted at an angle of10degrees and the element immersed alternately in recirculating water baths differing in temperature by 50 degF. The difference in temperature shall be indicated to the accuracy specified in Clause 5. b) Response 2) . The
28、 instrument shall be raised about40 degF above ambient temperature by inserting it in a suitably heated recirculating air oven for at least 30 minutes. The instrument shall then be withdrawn from the oven and placed in a current of air moving towards the element at not less than 15 ft/sec (5 m/sec).
29、 At least two-thirds of the difference in temperature shall be recorded within 30 seconds (Note), as required by Clause 6. 1) BS 1986, “Dimensional features of measuring and control instruments and panels for industrial processes”. 2) Instruments of identical design may be expected to have the same
30、response time and it will generally only be necessary for a type test to be carried out.BS3231:1960 2 BSI 04-2000 c) Certification. Certification of thermographs shall normally be carried out by a recognized testing station, but periodic checks on performance and examination for general compliance w
31、ith this specification may be conducted in the manner described above. NOTEAn instrument complying with Clause 6 is likely to have a response of about 3 seconds if the test described above is carried out using two water baths in place of an air oven and a current of air. 8 Marking The following info
32、rmation shall be permanently marked on the instrument in a convenient position for ready reference, preferably on the cover: a) The manufacturers name or trade mark. b) A serial number. c) The number of this British Standard, i.e.“BS3231”. d) The nominal range of the instrument. NOTEThe mark “BS 323
33、1” on a product is an indication by the manufacturer that it purports to comply with the requirements of this British Standard. The British Standards Institution is the owner of the registered certification trade mark shown below. The presence of the certification mark on a product is an additional
34、independent assurance that the product does comply with the requirements of the relevant British Standard. This certification mark may be used by the manufacturer only under licence from the BSI and particulars of the conditions under which licences are granted may be obtained from the Director, Bri
35、tish Standards Institution, 2 Park Street, London, W.1. 9 Packaging The instrument shall be packed for transit in such a manner as to minimize the possibility of accidental damage 3) . Detailed recommendations are given in Appendix A. 3) General guidance on methods of packaging and packaging materia
36、ls is given in BS 1133, “Packaging Code”.BS3231:1960 BSI 04-2000 3 Appendix A General recommendations for despatch by manufacturer and subsequent movement by customer from site to site a) Packaging. 1) Allow clock to run down. 2) Remove ink from pen-nib (absorb by blotting paper). 3) If reserve ink
37、is contained within the recorder remove the container and pack separately. 4) Operate pen lifter and fix by tying with thread or by using a rubber band, so that the pen-nib cannot hammer the chart drum while in transit. 5) Lock lid, or failing locking arrangement tie with broad tape, so as to preven
38、t the instrument opening if the package is inverted. 6) Cover windows with plywood, fibreboard or very stout paperboard fixed with adhesive tape, thus transferring padding pressure strain to the instrument case. 7) Enclose the instrument in a stout container with suitable cushioning, sufficient to w
39、ithstand normal transit risks, to prevent movement of the instrument within the container. b) Transport. 1) For local delivery by vehicle or for postal or air transport the container is sufficient. 2) For rail transport put container(s) inside a larger container with wood wool 4)cushioning. 3) For s
40、ea transport enclose container(s) in strong cases with wood wool 4)cushioning. 4) Provide usual warnings of fragility in English for internal transportation but use the appropriate international “Fragile” sign for export 5) . 4) See BS 2548, “Wood wool for general packaging purposes”. 5) Attention i
41、s drawn to BS 2770, “Recommendations for the pictorial marking of handling instructions for non-dangerous goods”.BS 3231:1960 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK vi
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