ASTM_D_5569_-_94.pdf

Designation:D 5569 94An American National StandardStandard Test Method forthe Determination of Static Flow of Electrical GradeMagnesium Oxide for Use in Sheathed Heating Elements1This standard is issued under the fixed designation D 5569;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the staticflow of electrical grade magnesium oxide for use in sheathedheating elements.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.2.Referenced Documents2.1 ASTM Standards:D 2755 Test Method of Sampling and Reduction to TestWeight of Electrical Grade Magnesium Oxide23.Terminology3.1 Definitions:3.1.1 angle of repose,nthe angle formed with the hori-zontal when a bulk solid moves,under the influence of gravity,over a stationary bulk solid,to a dynamic equilibrium.4.Summary of Test Method4.1 Granular magnesium oxide is allowed to flow through a6.35-mm(14-in.)diameter orifice from a 25.4-mm(1-in.)deepbed of material.The weight in grams of magnesium oxideflowing through the orifice by gravity is recorded as its staticflow.5.Significance and Use5.1 The static flow is an indicator of angle of repose ofgranular magnesium oxide.Sheathed heating-element filling-equipment performance is affected by the flow characteristicsof magnesium oxide as determined by this test method.6.Apparatus6.1 Static Flow Cup,with inside dimensions of 114.3-mm(4.5-in.)diameter and 24.6-mm(3132-in.)depth with a6.35-mm(0.25-in.)diameter centered orifice,equipped withrails at 0.8 mm(132in.)above rim of cup,two 110.6-mm(4-in.)high by 139.7-mm(5.5-in.)wide legs,and orificeclosure with handle(see Fig.1,Fig.2,and Fig.3 for suggesteddesign).6.2 Leveling Bar,aluminum or plastic(see Fig.4 forsuggested design).6.3 Balance,capable of weighing 100 g within 60.1 g.6.4 Weighing Pan,capable of containing and supporting 100g of magnesium oxide.6.5 Sample Container,4 L.7.Sampling7.1 Obtain sample of magnesium oxide,approximately 5kg,in accordance with Test Method D 2755.7.2 Store sample in a sealed container to protect againstatmospheric moisture.8.Procedure8.1 Place the 5-kg sample in the sample container.Fivespecimens will be taken from this sample to conduct the test.8.2 Place the static flow cup on a level surface that is free ofvibration.8.3 Close cup orifice.8.4 Fill cup to overflowing by pouring specimen fromcontainer into center of cup from a height of approximately 150mm(6 in.).8.5 Level specimen by pushing leveling bar across rails ofcup,removing excess material.Use care to achieve a levelsurface with a minimum of downward force applied to levelingbar,thus minimizing any movement of the cup.8.6 Place weighing pan below cup orifice.8.7 Open orifice closure,using care to minimize vibration,and allow the specimen to flow freely into weighing pan untilflow ceases.8.8 Weigh portion of specimen collected in the pan to thenearest 0.1 g.8.9 Empty cup and repeat 8.2 to 8.8 using four additionalspecimens of the original sample.1This test method is under the jurisdiction of ASTM Committee D-9 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.14 on Electric Heating Unit Insulation.Current edition approved June 15,1994.Published August 1994.2Annual Book of ASTM Standards,Vol 10.02.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has either been superceded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.8.10 Average the five specimen weights obtained and recordto the nearest 0.1 g.9.Report9.1 Report the following information:9.1.1 Proper identification of the sample,and9.1.2 Static flow to nearest 0.1 g.10.Precision and Bias10.1 PrecisionThe precision of this test method has notbeen determined.In a well equipped laboratory with trainedpersonnel,it is expected that duplicate determinations of staticflow will agree within 62.5 g.Determinations of static flow ofthe same sample in two laboratories are expected to agreewithin 64.2 g.10.2 BiasThe procedure in this test method has no biasbecause the value for static flow of magnesium oxide is definedin terms of this test method.11.Keywords11.1 angle of repose;magnesium oxide;sheathed heatingelements;static flowFIG.1 Static Flow Cup AssyFIG.2 Static Flow CupFIG.3 Orifice ClosureFIG.4 Leveling BarD 55692NOTICE:This stan