BS 4317-26-1991 Methods of test for cereals and pulses - Measurement of temperature of grain during bulk storage《谷物和豆类试验方法 第26部分 散装谷物储藏温度测量》.pdf

1、BRITISH STANDARD BS4317-26: 1991 ISO4112:1990 Methods of test for Cereals and pulses Part 26: Measurement of temperature of grain during bulk storageBS4317-26:1991 This British Standard, having been prepared under the directionof the Agriculture and Food Standards Policy Committee,was published unde

2、rthe authority of the Standards Board and comes into effect on 29March1991 BSI08-1999 The following BSI references relate to the work on this standard: Committee reference AFC/4 Draft for comment87/52930 DC ISBN 0 580 19459 0 Committees responsible for this British Standard The preparation of this B

3、ritish Standard was entrusted by the Agriculture and Food Standards Policy Committee (AFC/-) to Technical Committee AFC/4, upon which the following bodies were represented: AFRC Institute of Engineering Research Agricultural Engineers Association Association of Public Analysts British Edible Pulse A

4、ssociation Flour Milling and Baking Research Association Food and Drink Federation Grain and Feed Trade Association Home Grown Cereals Authority Institute of Brewing Institute of Food Science and Technology Intervention Board for Agricultural Produce Ministry of Agriculture, Fisheries and Food NABIM

5、 National Association of Commodity Cargo Superintendents and Surveyors National Farmers Union Natural Resources Institute Society of Chemical Industry United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS4317-26:1991 BSI 08-1999 i Cont

6、ents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Definitions 1 3 Principle 1 4 Apparatus 1 5 Procedure 1 6 Temperature records 2 Annex A (informative) Temperature-reading devices Inside back coverBS4317-26:1991 ii BSI 08-1999 National foreword This Part of BS4317

7、has been prepared under the direction of the Agriculture and Food Standards Policy Committee. It is identical with ISO4112:1990 “Cereals and pulses Guidance on measurement of the temperature of grain stored in bulk”, published by the International Organization for Standardization (ISO), and in the p

8、reparation of which the United Kingdom played a full part. 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 itself confer immunity from l

9、egal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment ta

10、ble on the inside front cover.BS4317-26:1991 BSI 08-1999 1 1 Scope This International Standard gives guidance on the measurement of the temperature of grain stored in silos or any other bulk store. 2 Definitions For the purposes of this International Standard, the following definitions apply. 2.1 gr

11、ain cereal grains and/or seeds of pulses 2.2 bulk store large store in which grain is stored unpackaged in large quantities 3 Principle Placing a series of thermometric probes throughout the mass of stored grain to detect or monitor changes in temperature. 4 Apparatus The type of apparatus or instal

12、lation shall be suitable for the size and shape of the store. For example, use a portable apparatus, for small stores; a semi-fixed or retractable apparatus, for horizontal stores, i.e.stores with extensive floor areas and limited height; a permanent installation, for vertical stores (silos). The ap

13、paratus shall comprise the following parts. 4.1 Thermometric probes, one or more, usually consisting of a rigid tube or flexible cable(4.1.1) with one or more temperature-sensing devices(4.1.2), together with their respective output conductors, which are housed in the tube or cable. When the probe i

14、s buried in the mass of grain, its response time to reach a steady temperature reading shall not exceed3min. The materials used to fabricate the thermometric probes shall be resistant to products employed for fumigation and to damage by rodents. Horizontal stores, emptied by means of a scraper, shal

15、l be equipped with retractable thermometric probes. NOTE 1Flexible cables suspended in vertical stores should be anchored at the bottom of the store to prevent dislocation during loading. 4.1.1 Rigid tubes or flexible cables, of appropriate length and diameter, made of glass fibre, metal or other su

16、itable material and, particularly for vertical stores, having the strength and rigidity to resist the very high tensile and compressive forces which occur when the store is filled and emptied. NOTE 2Forces on the tubes or cables increase with their diameter, depth of burial and with movement of the

17、grain during loading and unloading. Tensile forces of up to50kN may occur. A small diameter has the effect of reducing the strain at fastening points and simplifying the anchorage system. Conversely, larger diameters give greater rigidity which is particularly important for very deep, stores. 4.1.2

18、Temperature-sensing device (thermosensitive element), consisting of a thermistor, or thermocouple, or a resistance thermometer, or any other electrical temperature-sensing device capable of detecting changes in temperature of the order of0,5 C, with a working range up to70 C and a lower limit approp

19、riate for the local ambient temperatures. 4.2 Temperature-reading device, which may be supplemented by a recording instrument (seeAnnex A for further information). 4.3 Thermometric apparatus (for ventilated stores), placed at the air inlet to measure the temperature of the ventilation air. 5 Procedu

20、re 5.1 Positioning the apparatus Owing to the low thermal diffusivity in stored grain and the fact that measuring points shall be sufficiently close to each other to detect localized temperature changes within a short time of their occurring, the measuring points should be no more than3m apart from

21、each other in any direction. If for economic or other reasons, however, measurements are made at spacings of more than3m, this shall be recorded in the temperature records. For horizontal stores, the upper measuring points shall be1m to2m below the surface of the grain. It is essential that several

22、probes or cables be positioned in the plane of symmetry of the store. NOTE 3In stores of limited height, it may be sufficient that the temperature be determined0,3m below the surface of the grain,0,5m above the floor, and mid-way between these points. For vertical stores, the measuring points shall

23、be spaced at regular intervals along vertical probes or cables in the immediate proximity of the walls and of the top and bottom. It is essential also that one probe or cable be positioned on the axis of symmetry of the store.BS4317-26:1991 2 BSI 08-1999 5.2 Temperature readings 5.2.1 Frequency of r

24、eadings If the grain is in unfavourable storage conditions (high temperature and moisture content), read the temperatures at the measuring points in the mass of stored grain at frequent time intervals, for instance every24h. For favourable storage conditions (dryand cold grain), the frequency of rea

25、dings may be reduced (for example, to once a week). Persons responsible for storage facilities shall determine the frequency of temperature readings, taking into account the nature of the stored product, the moisture content of the product, the season of the year, the degree of insect infestation of

26、 the product, etc. 5.2.2 Particular requirements for ventilated stores Read and record the temperatures at the various measuring points in the mass of stored grain using the following procedure. If the ventilation is not in operation, carry out an initial temperature reading and then ventilate the g

27、rain for30min to45min, depending on the height of the store. Measure the temperature of the ventilation air at the inlet. NOTE 4During this short period of ventilation, the air at any hot spot present rises, thus heating the upper probe(s). Carry out a second temperature reading after ventilation, c

28、orrecting the value obtained where necessary to take account of the temperature of the ventilation air. If the result obtained between the initial and second temperature readings is approximately5 C or above, a hot spot may be presumed to be present and there is a risk of damage. Provisions shall be

29、 made (service contracts, reserves of spare parts) to ensure that the upper probes are never out of commission for longer than24h. 6 Temperature records The temperature records shall indicate the apparatus used, the temperatures recorded at the various measuring points, and the times at which the te

30、mperatures were measured. They shall also mention all operating conditions not specified in this International Standard, or regarded as optional, as well as any circumstances that may have influenced the readings. They shall include, if necessary, all information relating to the store in question an

31、d to the nature of the product stored.BS4317-26:1991 BSI 08-1999 Annex A (informative) Temperature-reading devices Reading devices differ according to the size of the installation. In small installations, the reading device may be an electrical or electronic measuring appliance, graduated in degrees

32、 Celsius, giving the temperature reading and fitted with a thermometric probe which is pushed into the mass of grain at the required measuring points. In larger installations, a control cabinet may be used. The control cabinet may simply hold the reading instruments and indicators. However, it may b

33、e more complex and include. an analog or digital indicator for either manual or automatic reading and recording of temperatures; a variation indicator showing any fluctuation in the temperature in relation to a set value; pre-set controls which, when the temperature rises above a pre-set value, auto

34、matically activate visual or audible alarm signals and possibly ventilation: a synoptic panel of the storage facility and its various storage compartments; automated temperature control whereby the measuring points are scanned according to a predetermined programme (for example, every6h,12h or24h),

35、the various measurements being printed on paper.BS4317-26: 1991 ISO4112:1990 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the internationa

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