BS 6094-1-1981 Methods for laboratory beating of pulps - Valley beater method《纸浆实验室打浆法 Valley打浆法》.pdf

1、BRITISH STANDARD BS 6094-1: 1981 ISO 5264-1: 1979 Methods for Laboratory beating of pulps Part 1: Valley beater method ISO title: Pulps Laboratory beating Part 1: Valley beater method UDC 676.024.6:676.054.6 216.82BS6094-1:1981 This British Standard, having been prepared under the directionof the Pa

2、pers StandardsCommittee, was published under the authority ofthe Executive Board and comesinto effect on 30January1981 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PAS/11 Draft for comment 78/60001 DC ISBN 0 580 11876 2 Cooperating organizations T

3、he Paper Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: British Paper and Board Industry Federation (PIF)* British Printing Industries Federation* Envelope Makers and Manufacturing Stationers Association* HM Customs and

4、Excise Her Majestys Stationery Office* Institute of Trading Standards Administration National Association of Paper Merchants National Economic Development Office Pira (The Research Association for the Paper and Board, Printing and Packaging Industries)* Royal Institute of Public Health and Hygiene T

5、he organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: British Fibreboard Packaging Association British Wood Pulp Association Chemical Industries Associatio

6、n Man-made Fibres Association Ministry of Agriculture, Fisheries and Food Ministry of Defence Post Office Society of British Printing Ink Manufacturers University of Manchester, Institute of Science and Technology Amendments issued since publication Amd. No. Date of issue CommentsBS6094-1:1981 BSI 1

7、2-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 0 Introduction 1 1 Scope 1 2 Field of application 1 3 References 1 4 Principle 1 5 Apparatus and auxiliary materials 1 6 Preparation of sample 1 7 Procedure 1 8 Test report 2 Annex A Valley beater 3 Annex B Cali

8、bration of the Valley beater 3 Figure Valley beater 6 Publications referred to Inside back coverBS6094-1:1981 ii BSI 12-1999 National foreword This British Standard has been prepared under the direction of the Paper Standards Committee. It is identical with ISO5264-1:1979 “Pulps Laboratory beating P

9、art 1: Valley beater method” which was developed by Technical Committee ISO/TC6, Paper, board and pulps, and was published by the International Organization for Standardization (ISO). This British Standard is published in two Parts. The other Part, already published, is Part2 “PFI mill method” which

10、 is identical with ISO5264-2 “Pulps Laboratory beating Part 2: PFI mill method”. Reference is made, in clause 1, “Scope”, to Part3 of ISO5264, which gives a method using a Jokro mill. It is not intended to publish a corresponding British Standard, because the Jokro mill is little or never used in th

11、e UnitedKingdom. 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 especially drawn t

12、o the following. The comma has been used throughout 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 to this standard, they should be read as “British Standard”. A

13、dditional information. Footnote2) to the last item in clause3 is no longer applicable as ISO5263:1979 has been published. There is no corresponding British Standard. The Technical Committee has reviewed the provisions of ISO5263, to which reference is made in note3 to7.1, and has decided that they a

14、re acceptable for use in conjunction with this standard. NOTEIn the footnote toB.1.4 a carborundum hone No.149 is given as an example of a suitable hone. In the United Kingdom these hones are obtainable through normal retail outlets from Carborundum Company Limited, Abrasive Mills, Trafford Park, Ma

15、nchester17. 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. Cross-references Internationa

16、l Standard Corresponding British Standard ISO 638:1978 BS 4502:1980 Method for determination of dry-matter content of pulps (Identical) ISO 4119:1978 BS 5878:1980 Method for determination of stock concentration of pulps (rapid method) (Identical) ISO 5264-2:1979 BS 6094 Methods for laboratory beatin

17、g of pulps Part 2:1981 PFI mill method (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will b

18、e indicated in the amendment table on the inside front cover.BS6094-1:1981 BSI 12-1999 1 0 Introduction It has been agreed that the ultimate aim of standardization of laboratory beating should be to develop one test method which is internationally acceptable and which, if possible, allows the energy

19、 consumption during beating to be measured. For practical reasons it has not proved possible to achieve this at present. Therefore, as an interim measure, in view of the widespread use of the following methods Valley beater, PFI mill, Jokro mill, it has been decided to provide agreed guidance on the

20、 use of these equipments in order to achieve consistency of results with each instrument. While all three methods will show a similar trend in respect of the pulp tested, the actual results cannot be correlated between different types of beater 1) . The position will be kept under review, and the me

21、thods will be replaced by a single method as soon as practicable. 1 Scope This International Standard specifies a method, using a Valley beater, for the laboratory beating of pulp. The description is limited to the furnishing and beating of the stock, the withdrawal and distribution of samples, and

22、the beating equipment. The beating is a preliminary step in testing the physical properties of pulp. Part 2 specifies a method of laboratory beating using a PFI mill and Part3 a method using a Jokromill. 2 Field of application In principle, this method is applicable to all kinds of pulp. NOTEIn prac

23、tice, the method may not give satisfactory results with certain extremely long-fibred pulps, such as cotton linters. 3 References ISO 638, Pulps Determination of dry matter content. ISO 4119, Pulps Determination of stock concentration (Rapid method). ISO 5263, Pulps Laboratory wet disintegration 2)

24、. 4 Principle A measured amount of pulp of specified stock concentration is beaten between the bars of the roll and the bedplate of a Valley beater. Samples of beaten pulp are taken at intervals during the beating. 5 Apparatus and auxiliary materials Ordinary laboratory equipment and 5.1 Valley beat

25、er, as described inAnnex A. 5.2 Timer. 5.3 Balance, capable of weighing the sample to an error of less than1g. 5.4 Distilled water, or deionized water, or water of similar quality. NOTEDistilled water, or water of similar quality, is particularly recommended with a view to obviating any difficulties

26、 that might arise from the use of different qualities of water by the interested parties. 6 Preparation of sample If the pulp is wet or air-dry, weigh out a sample for dry matter determination in accordance with ISO638. If the pulp is in slush form, determine the dry matter content in accordance wit

27、h ISO4119. Take an amount of the pulp corresponding to3605g of oven-dry pulp (do not cut the pulp, and avoid the use of cut edges). If the sample is in the form of machine-dried sheets or flash-dried slabs, soak the pulp thoroughly in5 litres of water (see5.4) at room temperature for not less than4h

28、. Tear the soaked pulp into pieces approximately25mm 25mm in size. It is essential that the pulp be thoroughly softened by soaking, to ensure that the preliminary disintegration results in a minimal beating effect. Wet pulps may be disintegrated without soaking. 7 Procedure 7.1 Disintegration The pr

29、eliminary disintegration is effected in the Valley beater (5.1) itself. 1) Should one of the three methods listed become the future standard method, that one of the methods should be chosen which works in the most economical way and yields the highest reproducibility of results obtained in different

30、 laboratories. At present, some countries are of the opinion that the PFI mill described in ISO5264-2 meets these requirements best of all. 2) At present at the stage of draft.BS6094-1:1981 2 BSI 12-1999 Lower the bedplate, and clamp it in the lowered position, so that the clearance between the roll

31、 and bedplate bars is at least10mm. Close the outlet of the beater tub with a stopper. Fill the tub with18 litres of water (5.4) at20 5 C, and start the motor. Slowly add, over a period of3 to5min, the pulp and the water used for wetting it. The total volume of pulp and water should be23,0 0,2 litre

32、s, to give a pulp concentration of approximately1,57% (m/m). Disintegrate the pulp with the bedplate still fixed in its lowered position. Free any pieces of pulp caught behind the roll or the adjacent shield, by moving the lever arm of the bedplate rapidly once or twice up and down during the course

33、 of disintegration. Pulps with an initial dry matter content of20% (m/m) or more normally disintegrate within30min after addition of all the pulp to the beater tub. Pulps with less than20% (m/m) dry matter content should disintegrate within5min. NOTE 1Where necessary for climatic reasons, a temperat

34、ure of25 5 C may be applied, provided that this is noted in the test report. NOTE 2Ensure that the pulp is completely disintegrated. Pulps that are difficult to disintegrate, such as unbleached sulphate pulp, may require a time exceeding30min for disintegration. NOTE 3A sample disintegrated as descr

35、ibed above may not be regarded as a sample of unbeaten pulp disintegrated in accordance with ISO5263. NOTE 4Hands must not be placed inside the beater while it is running. 7.2 Beating Check that the load on the bedplate lever is as specified, release the lever, and start the timer (5.2). Without int

36、erruption of the beating process, and without removal of the bedplate load, withdraw a total of five stock samples of1200ml (18,8g of fibres, oven-dry basis), distributed over the range of beating required. The following is an example of a schedule for sample removal: NOTE 1Even if the quantity of p

37、ulp withdrawn is not necessarily all used for testing, it is necessary that the stated quantity of pulp be withdrawn at the periods adopted. It can be expected that a change in the volume removed will change the rate of beating. NOTE 2After beating, clean the beater thoroughly with water and, if nec

38、essary, with a pitch solvent, with due consideration being given to the rubber diaphragm. NOTE 3If pulps are normally beaten to “Canadian Standard” freeness number values below300, or to Schopper-Riegler number values above40, frequent checks should be made of the calibration of the beater. NOTE 4If

39、 the drainability is measured, this should be done with a minimum of delay. 8 Test report The test report shall include the following particulars: a) the reference to this International Standard; b) all the indications necessary for complete identification of the sample; c) the time used for prelimi

40、nary disintegration; d) the time used for beating; e) the results obtained in the drainability test, if made (see note4 to7.2); f) any unusual features observed in the course of the procedure; g) any operations not specified in this International Standard or in the International Standards to which r

41、eference is made, or regarded as optional, which might have affected the results. Beating conditions: Load on the lever arm: 54 1N Rotational frequency of the roll: 8,3 0,2 s 1 Bleached and unbleached sulphite pulps, straw pulps and hardwood alkaline pulps: 5, 10, 15, 20, 30 min Bleached softwood al

42、kaline pulps: 5, 15, 30, 45, 60 min Unbleached softwood alkaline and other slow-beating pulps 5, 15, 30, 60, 90 minBS6094-1:1981 BSI 12-1999 3 Annex A Valley Beater (see theFigure) The bars of the roll and bedplate are made of stainless steel. The bedplate has a Brinell hardness of325 to375HB, and t

43、he roll flybars350 to400HB. The diameter of the roll is168mm; with the32 flybars inserted, it is190 to194mm. The thickness of each flybar is4,7mm, and the width of the roll152mm. The bedplate has7 bars set in lead, each3,2mm thick and2,4mm apart. The grooves between the bars are filled with strips o

44、f kiln-dried white oak. The bars are rectangular in cross-section and bent in the shape of a V with the apex of the V pointing in the flow direction of the stock, and the arms of the V forming an angle of5 with the direction of the roll axis. The width of the bedplate is159mm; it is ground to the sa

45、me curvature as the roll. The bedplate and the bottom of the beater tub are connected by a diaphragm of soft, elastic rubber, of thickness approximately1,5mm, installed in such a way that there is no tension in the diaphragm when the bedplate and beater roll are in contact. The bedplate is pressed a

46、gainst the roll by means of a lever; the ratio between the lever arms is1,94 to1; a load of5500gf, obtained by using suitable weights applied to the longer arm then produces a force of105N on the bedplate. The roll is run at a rotational frequency of8.3 0,2s 1and may conveniently be driven by a moto

47、r of approximately400W by a belt drive. The beater tub is provided with bolts for fixing the bedplate lever during grinding. The bedplate is balanced so that it is in equilibrium with23,0 litres of water in the beater when the beater is running. An extremely small force will then bring the roll and

48、bedplate into contact. To ensure reproducible beating, the following conditions shall be fulfilled: a) The beater roll shall run smoothly, without irregular vibrations. b) All the roll and bedplate bars shall make contact throughout their width. c) The threshold formed by the first bar of the bedpla

49、te, and the depth of grooves between the bedplate bars, shall be1,0 0,2mm. d) The leading edge of the flybars shall be rounded to a radius of approximately0,2 to0,3mm. e) All the bars shall be clean, undamaged and free from deposits and corrosion. Annex B Calibration of the Valley beater The following calibration procedure is designed to bring the beater to a condition which will remain stable during repeated use, and maintain reproducible laboratory sheet properties at a given beating degree, within a narrow range of beating t