實(shí)驗(yàn)室振動(dòng)式液體密度儀

本規(guī)程適用于密度范圍(650～3000)kg/m3的實(shí)驗(yàn)室振動(dòng)式液體密度儀(包括臺(tái)式振動(dòng)管密度儀和手持式振動(dòng)管密度儀，以下簡(jiǎn)稱密度儀)的首次檢定、后續(xù)檢定和使用中檢驗(yàn)。JJF1002—1998國(guó)家計(jì)量檢定規(guī)程編寫規(guī)則JJF1001—1998通用計(jì)量術(shù)語(yǔ)及定義JJF1059—1999測(cè)量不確定度與表示ISO15212-1振動(dòng)型密度儀第一部分：實(shí)驗(yàn)室儀器GB/T6682—2008分析實(shí)驗(yàn)室用水規(guī)格說(shuō)明和試驗(yàn)方法使用本規(guī)程時(shí)應(yīng)注意使用上述引用文獻(xiàn)的現(xiàn)行有效版本。3概述密度儀主要是由U形玻璃振動(dòng)管、電磁振蕩器、溫度控制器以及顯示單元和數(shù)據(jù)處理單元組成。其結(jié)構(gòu)見(jiàn)圖1。當(dāng)一定體積的液體充滿U形玻璃振動(dòng)管后，由于管內(nèi)物質(zhì)的質(zhì)量發(fā)生變化，使得振動(dòng)管的固有振動(dòng)頻率或特征頻率也發(fā)生變化。體積一定時(shí)，振動(dòng)管的頻率是管內(nèi)所充物質(zhì)質(zhì)量的函數(shù)。當(dāng)質(zhì)量增加時(shí)密度增加，頻率降低，振動(dòng)周期增大。反之，當(dāng)質(zhì)量減小時(shí)密度減小，振動(dòng)周期減小。二者之間的關(guān)系式簡(jiǎn)單描述進(jìn)樣管U進(jìn)樣管U形玻璃振動(dòng)管顯示器排放管24計(jì)量性能要求密度儀的計(jì)量性能要求見(jiàn)表1和表2。工作級(jí)最大允差士0.15士1.55通用技術(shù)要求密度儀外觀要求如下：密度儀應(yīng)具有下列標(biāo)志、標(biāo)識(shí)：儀器名稱、型號(hào)、編號(hào)、制造廠廠名和出廠日期；其標(biāo)志、標(biāo)識(shí)應(yīng)清晰。密度儀外表不應(yīng)有影響工作性能的機(jī)械損傷；顯示屏表面平整、潔凈、無(wú)劃痕，讀數(shù)清晰、完整；各調(diào)節(jié)器應(yīng)能正常調(diào)節(jié)，各開(kāi)關(guān)及按鍵接觸良好，能正常工作，各緊固件無(wú)松動(dòng)。6計(jì)量器具控制計(jì)量器具控制包括：首次檢定、后續(xù)檢定和使用中檢驗(yàn)。6.1檢定設(shè)備6.1.1檢定用標(biāo)準(zhǔn)器按“密度計(jì)量器具檢定系統(tǒng)”的規(guī)定配置。見(jiàn)表3。測(cè)量范圍測(cè)量范圍U=3×10-^kg/m2臺(tái)式振動(dòng)管密度標(biāo)3表3(續(xù))測(cè)量范圍測(cè)量范圍工作級(jí)6.1.1.1密度標(biāo)準(zhǔn)液體選取3個(gè)或4個(gè)密度標(biāo)準(zhǔn)液體，該液體必須是單一物質(zhì)，且具有穩(wěn)定的物理和化學(xué)性質(zhì)。其運(yùn)動(dòng)粘度應(yīng)不大于100mm2/s。標(biāo)準(zhǔn)液體的選取。盡可能在儀器測(cè)量范圍內(nèi)考密度儀的測(cè)量范圍為(650～2000)kg/m3時(shí)，應(yīng)選擇如下3種密度標(biāo)準(zhǔn)液體：(3)(1450～1650)kg/m3:溴苯或四氯乙烯；密度儀的測(cè)量范圍為(650～3.000)kg/m3時(shí)，可根據(jù)用戶需要增加一個(gè)檢定點(diǎn)，并選取如下密度標(biāo)準(zhǔn)液體：(4)(2200～2400)kg/m3:1.2,3-三溴丙烷。6.1.1.2振動(dòng)管臺(tái)式密度標(biāo)準(zhǔn)裝置：測(cè)量范圍為(650～3000)kg/m2,標(biāo)準(zhǔn)等級(jí)為0.01級(jí)的標(biāo)準(zhǔn)密度儀一臺(tái)。6.1.1.3一等密度計(jì)標(biāo)準(zhǔn)裝置：測(cè)量范圍(650～2000)kg/m2的連續(xù)型一等密度計(jì)6.1.1.4溫度計(jì)；范圍為(0～50)℃的二等標(biāo)準(zhǔn)水銀溫度計(jì)或準(zhǔn)確度不低于二等標(biāo)準(zhǔn)水銀溫度計(jì)的其他溫度計(jì)。6.1.1.5空盒氣壓表(檢定精密級(jí)和工作級(jí)用);范圍(80～106)kPa,最大允許誤差土0.25kPa,水銀氣壓表(檢定標(biāo)準(zhǔn)級(jí)用):范圍(80～106)kPa,最大允許誤差±0.03kPa。6.1.1.6相對(duì)濕度表：范圍20%～85%,最大允許誤差±5%。6.1.1.7清洗液：無(wú)水乙醇、蒸餾水、溶劑汽油、丙酮、石油醚、重鉻酸鉀洗液、甲苯、洗滌劑等。6.1.1.8注射器：(5～10)mL。6.1.1.9空氣干燥裝置：對(duì)于沒(méi)有空氣干燥泵的密度儀，可以外加一個(gè)微量空氣泵?？諝饬恳阅軌虼蹈蒛形管為宜；或者使用干燥的洗耳球，將U形管吹干。6.1.1.10實(shí)驗(yàn)室恒溫裝置：實(shí)驗(yàn)室內(nèi)應(yīng)有恒溫裝置，以保證室內(nèi)溫度、濕度能夠達(dá)到46.1,2.1環(huán)境溫度要求在(20±2)℃范圍內(nèi)，相對(duì)濕度20%～80%。度標(biāo)準(zhǔn)液體通常使用的溶解液見(jiàn)表4。清洗過(guò)后，用干燥空氣將其油醚(30～60沸程)等。然后再用于燥空氣將其吹出，并且凈化。壬烷四氧乙炳1.2,3-三溴丙烷(1)空氣自校將測(cè)量系統(tǒng)的溫度設(shè)定為20℃,并將干燥空氣充滿U形振動(dòng)管，待溫度穩(wěn)定后，記錄空氣密度值m和溫度值，同時(shí)記錄檢定環(huán)境的相對(duì)濕度及大氣壓力值，并計(jì)5氣密度示值進(jìn)行修正。(2)用除氣蒸餾水自校將測(cè)量系統(tǒng)的溫度設(shè)定為20℃,用新鮮的除氣蒸餾水充滿U形振動(dòng)管，并確保振動(dòng)管內(nèi)無(wú)氣泡，待溫度穩(wěn)定后，記錄水的密度值pxm和溫度值。按記錄的溫度值查附錄C中對(duì)應(yīng)的純水密度值pk。當(dāng)|px-Pxm|超出儀器說(shuō)明書所規(guī)定的要求時(shí)，需對(duì)水的密度示值進(jìn)行修正6.2.3.2工作級(jí)的密度儀可以不進(jìn)行空氣自校.對(duì)于具有自動(dòng)校準(zhǔn)功能的儀器，按說(shuō)明出要求設(shè)置好程序進(jìn)行自動(dòng)校準(zhǔn)。蒸餾水應(yīng)符合GB/T668220M的更求，水質(zhì)新鮮。先過(guò)濾后蒸餾。除去空氣的水應(yīng)謹(jǐn)慎保存，減步是動(dòng)，以盡量減少至一何為容入其中。6.2.4密度示值誤差和重復(fù)性的檢定6.2.4.1密度標(biāo)準(zhǔn)能體檢定法將選定的密度標(biāo)混液體注入并充病測(cè)屬指，待密度儀溫度已會(huì)后。記錄密度和溫度值。每個(gè)密度檢起這獨(dú)立測(cè)量3次十算平寫值3在測(cè)量1050)kg/m2的密度點(diǎn)時(shí)，用基審水重復(fù)6次，并家下式計(jì)算單次測(cè)量標(biāo)準(zhǔn)偏卷乙印重復(fù)性：注入密度標(biāo)準(zhǔn)做體時(shí)，應(yīng)仔細(xì)規(guī)在U形管內(nèi)有無(wú)氣泡，如公現(xiàn)有氣泡，應(yīng)將氣泡排出，直至無(wú)氣池手動(dòng)進(jìn)樣時(shí)，注無(wú)容應(yīng)繼續(xù)保持在樣品入口處。以免空地人U形管內(nèi)。對(duì)于具有自動(dòng)進(jìn)樣物能的儀器，按說(shuō)明書要求設(shè)置好程產(chǎn)進(jìn)行自動(dòng)測(cè)量，記錄密度和溫度值。6.2.4.2臺(tái)式振動(dòng)管密度標(biāo)準(zhǔn)發(fā)費(fèi)值定些門將被檢密度儀與標(biāo)準(zhǔn)裝置放置在工作臺(tái)工，設(shè)定溫度均為20℃,恒溫后，根據(jù)被檢儀器的測(cè)量范圍選取6.1.1.1中的4種或前3種密度標(biāo)準(zhǔn)液體，分別注入被檢密度儀與標(biāo)準(zhǔn)裝置中，觀察二者有無(wú)氣泡，如果有氣泡，需將氣泡排出，待溫度穩(wěn)定后，分別記錄標(biāo)準(zhǔn)裝置和被檢密度儀的密度和溫度值。每種液體獨(dú)立測(cè)量3次。按式(2)計(jì)算按下式計(jì)算密度示值誤差式中：Pm——標(biāo)準(zhǔn)裝置3次示值的平均值。6在測(cè)量(950～1050)kg/m2的密度點(diǎn)時(shí)，被檢儀器重復(fù)6次，按式(4)計(jì)算單次測(cè)量標(biāo)準(zhǔn)偏差，即重復(fù)性。6.2.4.3用一等密度標(biāo)準(zhǔn)裝置進(jìn)行檢定選取6.1.1.1中的前3種密度標(biāo)準(zhǔn)液體。分別將一等標(biāo)準(zhǔn)密度計(jì)放入溫度為(20±0.1)℃的盛有密度標(biāo)準(zhǔn)液體的檢定玻璃簡(jiǎn)中，用一等標(biāo)準(zhǔn)密度計(jì)對(duì)其進(jìn)行測(cè)量。同時(shí)，用被檢儀器也對(duì)其進(jìn)行測(cè)量。待溫度穩(wěn)定后，分別記錄一等密度計(jì)和被檢密度儀的密度和溫度值。每種液體獨(dú)立測(cè)量3次。按式(2)計(jì)算各自的密度平均值并計(jì)算密度示值誤差：式中：Pm——標(biāo)準(zhǔn)密度計(jì)3次示值的平均值修正后的實(shí)際密度值(包括證書修正值或毛細(xì)修正值等)。在測(cè)量(950～1050)kg/m2密度點(diǎn)時(shí)，被檢儀器重復(fù)6次，按式(4)計(jì)算單次測(cè)量標(biāo)準(zhǔn)偏差，即重復(fù)性。如果檢定液體和一等密度計(jì)證書上給出的工作液不同時(shí)，需要進(jìn)行毛細(xì)常數(shù)作用修正。修正公式如下：ay——證書上給出工作液的毛細(xì)常數(shù)，mm2;a?——所選液體的毛細(xì)常數(shù)，mm2;D———等密度計(jì)的干管平均直徑，mm;M———等密度計(jì)質(zhì)量，mg;π——圓周率，取3.14,密度標(biāo)準(zhǔn)液體檢定法作為仲裁的方法。6.3檢定結(jié)果處理按本規(guī)程要求檢定合格的密度儀發(fā)給檢定證書。不合格的密度儀發(fā)給檢定結(jié)果通知書。并注明不合格項(xiàng)目。當(dāng)密度儀不符合本級(jí)計(jì)量性能要求，但符合低一級(jí)別的計(jì)量性能要求時(shí)，可發(fā)給檢定證書，但要注明其合格的等級(jí)。6.4檢定周期檢定周期不超過(guò)1年。7檢定記錄格式受檢器示值受檢器誤差123231234568檢定證書和結(jié)果通知書內(nèi)頁(yè)格式外觀外附錄C999.099064999.097557999.996045909.094534999.093022999.091508999,089994999.A?47999.083923999.08280A999.080881999.079358999.077834999.07630999.068665999.09+999999.053290999.174999.050999.037298999.4999.0346859.999.042.458999.006463999.6%999.0039972200099998.974663998.973A8,971457098.969853998.968247998.966640998.965032980423998.96181998.958589998.9569756360998.953744998.952127998.950509998.948867269998.942400998.9407749988937520998.935812998.9342629982298.930999998.9293659098.909676998.908028998.906183-998.219.541.208-RM2G16257998.914614998.912969998.911323OLSEo7998.899769098.898114998,896458998.891801998.893142998.891482998.889821998.888159998.886406998.884832998.883167998.881500998.87983998.876494998.874822998.873150998.871477998.869802998.858127998.866450998.864772998,863093998.861412998.859731998.858049998.856365998.854680998.852994998.851307998.849619998.847930998,84623998842855998841161998839466998837770998836072998834374998832674998830974998,8292729臺(tái)表(續(xù))998.825865998.824160998.822453998,820746998.819037998.817327998.815616998.813904998.81219998.808762998.807045998.805327998.803609998.801889998.800168998.798445998.796722998.794998998.793272998.791545998.789817998.788088998.786358998.784627998.782895998.781161998.779427998.777691998.775954998.774216998.772477998.770737998.768995998.767253998.765509998.763765998.762019.998.760272998.756774998.755024998,753273998.751520998.749766998.748011998,746256998.744498998.74274998.739220998.737459998.735696998.733932998.732167998,730401998.728634998.726866998.72509998.721554998.719782908.718008998,716233098,714457998.712680998.710901998.709122998.70734998.703777998.701993998,700208998.698422998.696634998.694846998,693056998.691266998.689474998.687681998.685887998.684092998.682296998.680499998.678700998.676901998.675100998.673299998.671496998.669692998.667887998.666081998.664273998.662465998.660655998.658845998.657033998.655220998.653406998.651591998.649775998.647958998.646139998.644320998.642499998.640678998.638855998.637031998.635206998.633380998.631553998.629724998.627895998.626064998.624233998.622400998.620566998.618731998.616895998.615058998.613220998.611380998.609540998.607698998.605856998.604012998.602167998.600321998.598474998.596626998.594776998.592926998.591075998.589222998.587368998.585513998.583658998.581801998,579943998.578083998.576223998,574362998.572499998,570636998.568.771998.566905998.565038998.563170998.56130998.557560998.555688998.553814998.551940998.550064998.548187998.546310998.544431998.542551998.538787998.536904998.535020998,533134998.531248998.529360998.527471998.525582998.52369998.519905998.518011998.516116998.514220998.512322998,510424998.508524998.506623998.504721998.502818998.500914998.499009998.497103998.495196998.493288998.491378998.489468998.487556998.485643998.483730998.481815998.479899998,477982998.476.064998.474144998.472224998.470303998,468380998,46645998.462606998.460679998.458752998.456823998.454893998.452961998.451029998.449096998.447161998.445226998.443289998.441352998.439413998.437473998.435532998.433591998.431648998.429703998.427758998.425812998.423865998.421916998.419967998.418016998.416064998.414112998.412158998.410.203998.40824998.404332998.402373998.400412998.398451998.396489998.394525998.392561998.390595998.388628表(續(xù))二998.384691998.382722998.380751998.378778998.376805998.374831998.372856998,370879998.36890998.364944998.362963998.360981998.358998998.357015998.355030998.353044998.351056998.349068998.347079998,345089998.343097998.341105998.339111998,337117998.335121998.333124998.331127998.32912998.325127998.323125998.321122998.319117998.317112998.315106998.313099998.311090998.309081998.307.070998.305058998.303046998.301032998,299017998.297001998.294984998.292966998.290947998.288927998.286906998.284883998.282860998.280835998.278810998.276783998.274756998.272727998,270697998.26866998.264602998.262568998.260533998.258497998.256460998.254421998.252382998.250342998.248301998.244215998.242170998.240124998.238078998.236030998,233981998.231931998.229880998.22782998.223721998.221666998.219610998.217553998.215495998.213435998.211375.998.209313998.207251998.205187998.203123998.201057998.198990998.196923998.194854998.192784998.190713998.188641998.186568998.184494998.182419998.180343998.178265998.176187998.174108998.172027998.169946998.167863998.165780998.161610998.159523998.157435998.155346998.153256998.151166998.149074998.146981998.144887998.140695998.138598998.136500998.134401998.132301998.130199998.128.097998.125993998.12388998.119677998.117569998.115460998.113351998.111240998.109128998.107015998.104901998.102787998.100671998,098554998.096436998,094316998,092196998.090075998,087953998.085830998.083705998.08158998.077326998.075198998.073068998.070938998.068806998.066673998,064540998.062405998.060269998.058133998.055995998.053856998.051716998.049575998.047433998,045290998.043.146998.011001998.038855998.036708998.034560998,032410998.030260998.028109998.025956998.023803998.021649998.019493998.01733998.013021998,010861998.008701998.006539998.004376998.002213998.000048997.997882997.995715997.993547997.991379997,989209997.987038997.984866997.982693997.980519997,978344997.976168997,97399997.969633997.967453997.965272997.963.090997.960906997.958722997.956537997,954350997.95216997.947785997.945595997.943403997.941211997.939017997.936822997.934627997.932430997.930233997.928034997.925834997.923633997.921432997.919229997.917025997.914820997.912614997.910407997,908200997,905991997.903781997.901570997,899358997.897145997.894931997.892716997.890499997.888282997.88606河997.881625997.879404997.877182997.874958997.872734997.870509997.858282997.866055997.863827997.859367997.857136997.854903997.852670997.850435997.848200997.845963997.843726997.841487997.837007997.834766997.832523997.830280907.828.026407.825789997.823543997.821295997.819016897.814546997.812294997.769319997.767047992097.762500997.760225997.757949097.507297.753394997.751997.746554997.74427207.931989997.739705.997.737420997.735134997.732842<07N30558997.728997.723688997.72197.719103997.716809997.714513997.712217997.7099209000A622997.70532997.654487997.82166997.649842997.8751997.631220997.878997.626554997.62422997.607853997.856)997.603997.8008234598478997.66997.659129997.656808997.638.341997.635881997.610-8997.612534997.59hf997.589087997.562997.565541997.563181997.560820997.55862497.5560*0*553731MWEF766997.549066007F16E33997.537155997.53419A532410997.530036997.527.661997.525285997.52290894,0530997.518997.513.390997.5110087:08.625997.506242997.503857997.501471997.499081-8096696997.4943997.489527997.4871359997.482349997.479954997.477558997.476002067.472764907.470365997.465565997.463163997.4606458352997,455953997.45307t997.441505997.439093997.436681971017S853615.27021997.424604997.422186997.419766997.417346997.414925997.412503997.410079907.707855997.405230997.402804997.400377997.397949997.393090997.390659997.388226997.385793997.383360997.380925997.378489997.376052997.373614997.371175997.368735997.366294997.363852997.361410997.358966997.356521997.354076997.351629997.349181997.346733997.344283997,341832997.339381997.336928997.334475997.332.020997.329565997.327108997.324651表(續(xù))997.319733997.317273997.314812997.312349997.309886997.307422997.304957997.302491997.300024997.295086997.292.616997.290145997.287673997.285200997.282727997.280252997.277776997.275299997.272821997.270342997.267863997.265382997.262900997.260418997.257934997.255449997.252964997.250477997,247990997.245501997.243012997.240522997.238030997.235538997.233045997.230550997.228055997.225559997.220564997.218065997.215565997.213064997.210562997.208059997.205555997.203050997.200544997.195530997.193021997.190511997.188001997.185489997.182976997.180463997.177948997.175433997.170399997.167881997.165361997.162841997.160320997.157798997.155275997.152751997.150225997.147699997.145172997.142644997.140116997.137586997.135055997.132523997.129990997.127457997.124922997.122386997.119850997.117312997.114774997.112234997.109694997.107153997.104610997.102067997.099523997.096977997.094431997.091884997.089336997.086787997.084237997.081686997.079134997.076582997.074028997.071473997.068917997.066361997.063803997.061244997.05868