1、BRITISH STANDARD BS2096:1954 Method of testing oil-fired rotary dryersfor use in asphalt and coated macadamplant UDC625.85.088:66.04763BS2096:1954 This BritishStandard, having been approved by the Road Engineering Industry StandardsCommittee and endorsed by the Chairman oftheEngineering Divisional C
2、ouncil, was published undertheauthority of the GeneralCouncil on 4 March1954 BSI12-1999 ISBN 0 580 34145 3 Co-operating organizations The Road Engineering Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Governmen
3、t departments and scientific and industrial organizations: Air Ministry* Federation of Coated Macadam Industries* Asphalt Roads Association* Federation of Manufacturers of Contractors Association of Consulting Engineers Plant* (Incorporated) Institute of Petroleum Ballast, Sand and Allied Trades Ass
4、ociation Institution of Civil Engineers* British Road Tar Association* Institution of Highway Engineers* British Tarpaviors Federation* Institution of Municipal Engineers* Cement and Concrete Association* Institution of Structural Engineers County Surveyors Society* Ministry of Transport and Civil A
5、viation* D.S.I.R. Road Research Laboratory* Road Emulsion Association* Federation of Civil Engineering Contractors* Roads Improvement Association The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were direct
6、ly represented on the committee entrusted with the preparation of this BritishStandard: Association of Road Surface Dressing Limestone Federation Contractors Ministry of Supply British Compressed Air Society Ministry of Works British Engineers Association National Federation of Building Trades Briti
7、sh Granite and Whinstone Federation Employers British Slag Macadam Federation Reinforced Concrete Association Contractors Plant Association Road Roller Manufacturers D.S.I.R. Building Research Station War Office Amendments issued since publication Amd. No. Date CommentsBS2096:1954 BSI 12-1999 i Cont
8、ents Page Co-operating organizations Inside front cover Foreword ii Part 1. General conditions 1 Scope 1 2 Conditions of test 1 3 Measurements required 1 4 Duration of test 1 5 Consistency of aggregate feed 1 6 Test procedure 1 Part 2. Recommended conditions of test (For use when special conditions
9、arenotlaid down) 7 Recommended conditions of test 3 Appendix Typical form for recording the results of BritishStandard test on oil-fired rotary dryer 5 Table 1 Recommended conditions of test 4BS2096:1954 ii BSI 12-1999 Foreword This standard makes reference to the following BritishStandards: BS63, S
10、ingle-sized roadstone and chippings. BS594, Rolled asphalt, asphaltic bitumen and fluxed lake asphalt (hot process). BS802, Tarmacadam and tar carpets (granite, limestone and slag aggregate). BS812, Methods for the sampling and testing of mineral aggregates, sands and fillers. BS1241, Tarmacadam and
11、 tar carpets (gravel aggregate). BS1621, Bitumen macadam with crushed rock or slag aggregate. BS1690, Fine cold asphalt. BS2040, Bitumen macadam with gravel aggregate. The output of a mixing plant is often determined by the output of its drying and heating unit, and so far there has not been an acce
12、pted basis for measuring the performance of this unit under standardized conditions. To meet this need the plant manufacturers, the plant users and the Road Research Laboratory (Department of Scientific and Industrial Research) have co-operated with the Road Engineering Industry Standards Committee,
13、 in the production of the present standard. This standard provides a method of testing oil-fired rotary dryers of both continuous and batch types under conditions of composition and temperature agreed between the parties concerned. When the user does not lay down particular conditions, the recommend
14、ed test conditions given in Part2 may be used to cover the production of rolled asphalt, coated macadam and fine cold asphalt. These recommendations also form a basis upon which a manufacturer can state the output of oil-fired rotary dryers. A British Standard does not purport to include all the nec
15、essary 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, pagesi andii, pages1
16、 to7 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.BS2096:1954 BSI 12-1999 1 Part 1. General conditions 1 Scope This BritishStandard lays down a standard method f
17、or testing oil-fired rotary aggregate dryers of both continuous and batch types, and for reporting the results. Recommended test conditions corresponding to the requirements in the manufacture of rolled asphalt, coated macadam and fine cold asphalt are included for use when special test conditions a
18、re not laid down, and as a basis upon which manufacturers may declare the output of dryers. 2 Conditions of test Before starting the test the feed of the dryer shall be adjusted to the rated output of the plant and the following conditions of test shall be approved: Type of aggregate to be used. Gra
19、ding of aggregate. Moisture content in aggregate. Temperature at discharge. Moisture content in aggregate after drying. Where special test conditions are not laid down the recommended conditions of test given in Table 1 may be adopted for dryers to be used in the manufacture of rolled asphalt, coate
20、d macadam or fine cold asphalt. 3 Measurements required The following measurements shall be made: NOTEThe temperature and humidity of the air shall be recorded and an indication given of the strength of the wind. 4 Duration of test The test period shall be at least30minutes. Immediately before the b
21、eginning of the test period the dryer shall be run under test conditions for at least15minutes, or for such longer time as may be required for stable conditions to be obtained. No variation in conditions shall be made during the period of the test except minor variations (madeeither manually or auto
22、matically) in burner settings to control the temperature. 5 Consistency of aggregate feed Means shall be provided to maintain a constant composition and constant rate of feed throughout the test period. The ratio of material passing and retained on an ( in. mesh should be accurately controlled. A co
23、nstant feed shall be maintained until the last test results have been recorded. In testing batch dryers the time cycle shall be constant throughout the period of test. 6 Test procedure a) Output. The output shall normally be measured at the outlet of the dryer. Where practicable the entire quantity
24、of aggregate dried during the test period shall be discharged as directly as possible into tared vehicles and weighed on an approved weighbridge. When the test is carried out in the course of normal production or on large continuous dryers, where it is not convenient to weigh the whole output, at le
25、ast six measurements shall be made, taking the discharge for short periods only, at regular intervals. A tared container should be moved into position to catch the whole flow, or the flow diverted to such a container, for a period which can be accurately timed by a stop watch (e.g.10sec.30sec. accor
26、ding to the capacity of the dryer being tested). The rate of flow in tons per hour shall be calculated from the weight of the aggregate in the container. b) Determination of moisture content. At least six samples of the aggregate shall be taken at approximately even intervals throughout the test per
27、iod, from both the feed and the discharge ends of the dryer. Where possible, quantities of about“ cwt. shall be taken by catching the whole flow in a container inserted into the stream of material. Each of these batches shall be reduced on a sample splitter or “quartered” to give a final sample of a
28、bout10lb. which shall be put into a suitable previously-weighed container, for subsequent determination of the moisture content. Where possible the sample and container shall be weighed immediately to obtain the weight of the sample and its moisture. Care shall be taken to minimize the loss of moist
29、ure, particularly from warm material, during the sampling procedure. If immediate weighing is not possible, then an air-tight container shall be used, such as a lever-lid tin, and this container and its contents shall be weighed before unsealing. A balance capable of weighing up to7kg., readable and
30、 accurate to1.0g., shall be used. a) The output of aggregate in tons per hour. b) The moisture content before and after drying. c) The temperature d) The grading of the aggregate e) The fuel consumption in gallons per hour and in gallons per ton of output. BS2096:1954 2 BSI 12-1999 The sample should
31、 be thoroughly dried either in a well-ventilated oven at105110 C. (221230 F.) for24hours, or by heating over a burner in an open tray, with constant stirring, for30minutes after all visible evidences of moisture have disappeared. This method of drying should be repeated on the first sample to ensure
32、 that no further loss of weight occurs. The moisture content of the sample is the difference between the initial and final dried weight expressed as a percentage of the final weight. If the system of feeding the dryer is such that the above method of sampling would not give reasonably representative
33、 samples of mixed constituents at the feed end, then separate sets of samples shall be taken from each constituent of the feed, their moisture contents measured independently, and the average moisture content calculated from the ratios of the various constituents used in the mixed feed material. Thi
34、s ratio may have to be estimated from the grading as referred to under d). c) Temperature measurement. When the feed is from open stock piles, two or three readings of input temperature (measured by inserting a thermometer deeply into the heap) will be adequate. Should there be, reason to expect var
35、iations in feed temperature (e.g.when feeding from bulk storage bins of pre-dried material), then samples should be taken by the same method and of the same frequency as laid down below for the outlet temperature determination. Temperature measurements shall be made on the aggregate leaving the drye
36、r at regular intervals during the period of the test, so that at least six results are obtained during the period of the test. The samples shall be taken by inserting a lagged container 1)into the stream of aggregate, leaving the dryer so as to catch the whole flow for a period sufficient to collect
37、 about2030lb. of material. A lid shall be placed on the lagged container and the aggregate inside shall be mixed gently at intervals for five minutes to allow the temperature of the different particle sizes to even out; the temperature shall then be determined. A can of3in. diameter by6in. deep may
38、be used on asphaltic materials where the sand content is greater than50percent. The thermometers used should have a range appropriate to the temperature of the materials, say050 C. (32122 F.) for the feed materials, and0260 C. (32500 F.) for the discharge, and their thermal capacity should not excee
39、d that of a mercury-in-glass thermometer of about! in. diameter. The thermometer used for the discharge temperature should be kept in some of the hot material of each batch till the following batch is ready. d) Grading of aggregate. During the process of “quartering” the batches referred to inb) a s
40、ufficient quantity shall be retained from each batch for drying and sieving in accordance with BS812 2) . The sample dried for determination of moisture content, if of adequate size, may be used for this grading. If two or more constituents of the aggregate are fed in sequence through the same feed
41、hopper, samples taken as described inb) may not be representative of the mixed feed materials. In such cases, accurate sieve analysis of the feed cannot be made. An approximation should be made by taking sets of samples, each set comprising a sample of each constituent of the feed as brought to-the
42、feed hopper. These samples should be graded separately and the composite grading obtained by combining the results in the proportions of each constituent used in the feed. If this result is not in reasonable agreement with the grading of the discharged materials, then combinations of different propo
43、rtions of the constituent gradings should be tried, due allowance being made for possible loss of fines during drying, until ratios are found which give a composite grading as close as possible to that of the discharged material. The proportions so found shall be taken as those of the feed material
44、for the purposes of estimation of the moisture content in b). e) Oil consumption. The total quantity of oil used during the test period shall be measured to an accuracy of 2“ per cent. Where possible, a small service fuel tank mounted on a scale, or so connected that it can be weighed or measured ac
45、curately by dipping at the beginning and end of the test period, should be used, and the quantity of oil burned calculated from the difference in readings. 1) Before taking the first sample, the container should be brought to temperature by taking a few trial samples before the start of the test per
46、iod 2) BS812, “Methods for the sampling and testing of mineral aggregates, sands and fillers”BS2096:1954 BSI 12-1999 3 Alternatively, the oil level in the main tank should be measured at the beginning and end of the period. The duration should be such that the change of level is at least1“ in. and t
47、he measurement should be made to an accuracy of 1 / 16 in. If a change of level as indicated is not achieved, a service tank must be fitted. All other conditions affecting the level should be the same at the beginning and end of the period. If the tank is of such a shape that the surface area of the
48、 oil can be accurately measured, and does not vary appreciably between the two levels, then the quantity can be calculated from the change of level. If the tank shape is irregular, the quantity should be measured indirectly. When the burners are off, the level should be restored to the initial posit
49、ion. Oil should then be drawn off into separate containers, in which it can be measured, until the level in the tank falls to the lower test level. The quantity drawn off shall be taken as the consumption during the test. In some circumstances it may be more convenient to add a measured quantity of oil to raise the level in the tank from the lower to the higher test level. The oil consumption shall be expressed in gallons per hour, and in gallons per ton of aggregate dried, the type, calorific value and specific gravity of oil used being speci
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