BS-6057-2-1987 ISO-123-1985.pdf

BRITISH STANDARD BS 6057-2: 1987 ISO 123:1985 Rubber latices Part 2: Sampling ISO title: Rubber latex Sampling NOTEAttention is drawn to BS 6057-0 “General introduction” issued separately. UDC 678.031:620.113.42 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 This British Standard, having been prepared under the direction of the Rubber Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 September 1987 © BSI 10-1999 The Committees responsible for this British Standard are shown in Part 0 The following BSI references relate to the work on this standard: Committee reference RUM/38 Draft for comment 84/36676 DC ISBN 0 580 16025 4 National foreword This Part of BS 6057 is identical with ISO 123:1985 “Rubber latex Sampling” published by the International Organization for Standardization (ISO). It supersedes clause 2 of BS 1672:1972 and clause 3 of BS 3397:1976 which are being deleted by separate amendments. 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 identical with those used in British Standards; attention is drawn especially to the following. Wherever the words “International Standard” or “second edition of ISO 123” appear, referring to this standard, they should be read as “Part of BS 6057”. 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. The Technical Committee has reviewed the provisions of ISO 3310-1:1982 to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. Attention is drawn to BS 410 “Specification for test sieves” which is related to ISO 3310-1. 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 legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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 table on the inside front cover. Cross-references International StandardCorresponding British Standard ISO 124:1974BS 6057 Rubber latices Section 3.2:1981 Determination of total solids content of rubber latices (Identical) ISO 1795:1974BS 6315:1982 Methods for sampling and sample preparation of raw rubber (Technically equivalent) Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 © BSI 10-1999i Contents Page National forewordInside front cover 0Introduction1 1Scope and field of application1 2References1 3Definitions1 4Principle1 5Apparatus1 6Sampling2 7Labelling of laboratory sample and the test sample3 8Test report3 Figure Sampling tube for drums, tank cars and smaller tanks (not to scale)4 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 © BSI 10-19991 0 Introduction This second edition of ISO 123 gives more precise definitions, specifies the apparatus in more detail and clarifies some ambiguity on preliminary testing. The method of homogenizing latex in drums fitted with bungs has been altered, and in order to safeguard against stratification closer agreement in total solids content is required between samples drawn from different levels. 1 Scope and field of application This International Standard specifies procedures for the sampling of natural rubber latex concentrate containing preservative agents and also for the sampling of synthetic rubber latices. It is suitable for the sampling of rubber latex that is contained in drums, tank cars, or tanks. 2 References ISO 124, Rubber latices Determination of total solids content. ISO 1795, Raw rubber in bales Sampling. ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. 3 Definitions For the purpose of this International Standard, the following definitions apply. 3.1 lot a definite quantity of latex processed or produced under conditions which are presumed uniform, from which a test sample (see 3.4) is required the lot may be in one or more containers or vessels, for example it may consist of several drums of the same latex 3.2 sample any quantity of latex that is drawn from the lot 3.3 laboratory sample a quantity of latex intended for laboratory inspection and testing and that is representative of the lot 3.4 test sample a quantity of the latex that is suitable for testing obtained by filtering the laboratory sample NOTEThe laboratory sample, not the test sample, is used for the determination of coagulum content. 4 Principle The latex is agitated thoroughly to obtain a homogeneous bulk. A representative sample (3.3) is taken from the bulk of the latex. The test sample (3.4) is prepared from the laboratory sample (3.3). 5 Apparatus 5.1 Stirrer, for homogenization of latex in drums. For open-headed drums, use either 5.1.1 or 5.1.2. For drums fitted with a bung, use 5.1.3. 5.1.1 Perforated stainless steel disk plunger, of diameter approximately 150 mm, with holes of diameter approximately 10 mm. 5.1.2 Motor-driven stirrer, with a rotational frequency of 100 to 700 r/min. A suitable type of stirrer consists of a collapsible two-bladed stainless steel propeller of 110 mm minimum diameter when fully opened, mounted on a stainless steel shaft sufficiently long for the propeller to be at a distance of about one-tenth the height of the latex from the bottom of the drum. If desired, two propellers may be used on the same shaft, in which case the lower one shall meet the foregoing requirements as regards position. The shaft speed shall give a brisk turnover without creating a vortex. The part of the equipment immersed in the latex shall not contain copper. 5.1.3 Motor-driven drum roller, capable of rotating a drum at approximately 10 r/min. 5.2 Sampling tubes for latex in drums Use either 5.2.1 or 5.2.2. 5.2.1 Glass tube, of internal diameter 10 to 15 mm and length at least 1 m, open at both ends and having a stopper for closing the tube while withdrawing the latex. 5.2.2 Stainless steel sampling tube, of internal diameter approximately 25 mm and length at least 1 m, the bottom of which can be opened or closed by remote control. An outline drawing of a suitable design is given in the Figure. 5.3 Sampling devices for latex in tank cars or tanks Use 5.3.1 for sampling latex the depth of which is 3 m or more. Use either 5.3.2 or 5.3.1 for sampling latex the depth of which is less than 3 m. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 2 © BSI 10-1999 5.3.1 Sampling vessel, consisting of a weighted, cylindrical, stainless steel vessel of capacity approximately 1 dm3, closed by a bung that can be removed by remote control. The weight of the vessel shall be sufficient to ensure that when empty and closed it will sink freely through the latex. To the top of the cylinder there are attached, to at least two points, strong cords of material inert to the latex, of length greater than the depth of the latex that is to be sampled. 5.3.2 Stainless steel sampling tube, of internal diameter 25 mm and length 3 m, the bottom of which can be opened or closed by remote control. An outline drawing of suitable design is given in the Figure. 5.4 Beakers, of capacity 2 dm3, for reception of the latex from the sampling tube or sampling vessel. The beaker(s) shall be shock-resistant and have a smooth inner surface that is chemically resistant to the latex. 5.5 Sample bottles, of capacity 1 dm3, with screw caps. The bottles shall have a smooth inner surface and be composed of an impermeable material that is chemically resistant to the latex. Glass or some types of plastics are suitable materials. Thin or flexible plastics containers shall not be used. 5.6 Stainless steel wire cloth, with an average aperture width of 180 ± 10 4m, complying with ISO 3310-1. 6 Sampling At all stages of sampling, prevent the introduction of air into the latex and keep exposure of the latex to air to a minimum. 6.1 Preliminary examination Examine the latex visually for the presence of gross coagulum, skin, and foreign matter. 6.2 Sampling from drums 6.2.1 Homogenization Homogenize the latex manually as specified in 6.2.1.1 or 6.2.1.2, whichever is appropriate, or mechanically as specified in 6.2.1.3. 6.2.1.1 If the drum is fitted with a bung and manual or mechanical homogenization of the latex cannot be achieved, place the drum on a drum roller (5.1.3) and roll for 24 h at about 10 r/min. 6.2.1.2 If the drum is of the open-head type, remove the end head and stir the contents thoroughly for at least 10 min, preferably by means of the perforated stainless steel disk plunger (5.1.1). 6.2.1.3 Agitate the contents of the drum by means of the motor-driven stirrer (5.1.2) for 10 min to homogenize the latex. Avoid excessive stirring. 6.2.2 Taking of laboratory sample After homogenization of the latex (6.2.1), take the laboratory sample without delay using the glass tube (5.2.1) or the stainless steel sampling tube (5.2.2). In the case of the glass tube, ensure that it is clean and dry and slowly insert it in the drum until it reaches the bottom. Then close the upper end of the tube with the stopper, withdraw it and transfer its contents to a clean, dry sample bottle (5.5). Repeat the operation until sufficient latex has been obtained to fill the sample bottle, leaving an air space of 2 to 5 % (to allow for thermal expansion). Screw the cap firmly on the bottle. In the case of the stainless steel sampling tube, slowly insert it in the drum, holding the bottom of the tube open, until it reaches the bottom. Then release the handle to close the bottom of the tube and withdraw the tube. Transfer the contents of the tube into a beaker (5.4) by depressing the handle. Repeat the operation until sufficient latex has been obtained. Transfer the latex from the beaker to a clean, dry sample bottle (5.5), leaving an air space of 2 to 5 % and screw the cap firmly on the bottle. 6.2.3 Sampling from several drums Where sampling of the same latex from several drums is required, for example 10 % sampling of a latex, the amount of latex drawn from each drum may be reduced proportionately. Combine and stir the individual samples and bottle the resultant laboratory sample. 6.3 Sampling from tank cars and tanks 6.3.1 Sampling operation Use the sampling vessel (5.3.1) or sampling tube (5.3.2), whichever is appropriate. Operate the sampling vessel (5.3.1) by lowering it, with the bung in place, into the latex to the required depth and then pulling out the bung. Allow a few seconds for the vessel to fill with latex and then pull it up and transfer its contents to a beaker (5.4). Transfer the latex to the sample bottle (5.5), leaving an air space of 2 to 5 % (to allow for thermal expansion) and screw the cap firmly on the bottle. Operate the sampling tube (5.3.2) by inserting it, with the bottom closed, into the latex to the required depth and then, by depressing the handle, opening the bottom of the tube. After the tube has filled with latex, release the handle to close the bottom and withdraw the tube. Transfer the contents of the tube into a beaker (5.4) and transfer the latex to the sample bottle (5.5), leaving an air space of 2 to 5 %. Screw the cap firmly on the bottle. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 © BSI 10-19993 6.3.2 Testing for homogeneity Take separate samples 100 mm from the top surface and 100 mm from the bottom of the latex. Determine the total solids content by the method specified in ISO 124. If the results from the top and bottom samples do not agree within 0,5 % (m/m) total solids, thoroughly rehomogenize the complete lot until samples obtained do agree within this tolerance. NOTEThorough agitation can be achieved with an efficient mechanical stirrer or by pumping the latex around or into another container. 6.3.3 Taking of laboratory sample After the degree of homogeneity specified in 6.3.2 has been achieved, take three samples of similar volume, the first half-way between the top and the centre of the latex, the second at the centre of the latex and the third half-way between the centre and the bottom of the latex. Combine and stir the three samples and transfer the resultant laboratory sample to a sample bottle (5.5). NOTE 1If the sampling tube (5.3.2) is used, a single sample may be taken by inserting the tube, with the bottom held open, to the bottom of the latex and then closing the bottom of the tube before withdrawing it from the latex. NOTE 2Coagulum content is determined on the laboratory sample, not the test sample. 6.4 Preparation of test sample Stir the laboratory sample carefully and filter it through the stainless steel wire cloth (5.6). Transfer the filtered latex to another sample bottle (5.5), leaving an air space of 2 to 5 %, and screw the cap firmly on the bottle. 7 Labelling of laboratory sample and the test sample These samples should be labelled and contain on the label a) a description of the material; b) the size and particulars of consignment (tank-wagon, tank, ship, barrel, drum); c) the designation and reference number of the sample; d) the consigner; e) the place of sampling; f) the date of sampling; g) the name of the sampler. 8 Test report The test report shall include the following information: a) a reference to this International Standard; b) all details necessary for the identification of the test sample; c) frequency of sampling; d) a record of creaming, visible gross coagulum, skin and foreign matter (if any) present in the original container; e) any unusual features noted during the sampling; f) any operation not included in this International Standard or regarded as optional. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 4 © BSI 10-1999 Figure Sampling tube for drums, tank cars and smaller tanks (not to scale) Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 15:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6057-2:1987 © BSI 10-1999 Publications referred to See national foreword. Licensed Copy: sheff