Tuyen tap bao cdo khoa hgc Hgi nghi Khoa hgc ky thuat Do luflng toan qufic Ian thtt IV Hd Ngi, 11-2005 iCkl TIEN AP DUNG MAY NGAM QUANG HOC L ^ P BANG DUNG TICH CHO BE TRU DUNG Nguyin Cao Phuc - Phdng Dung tich-Luu lugng, Trung tdm Do ludng Tdm tdt: Sd dung thiii bi ngdm quang hgc gdm mdy ngdm ngang vd mdy ngdm thang ddng lap bdng dung tich cho bi tru ddng Idn ddu tiin dugc phdng Dung tich-Luu Ittgng, Trung Idm ludng dp dung vdl ndm gdn ddy Bdi viet ndy gidi thiiu qud trinh nghiin cdu cdi lien cdc mdy ngdm quang hgc dtm gidn thdnh bd thiit bi do, lap bdng dung tich bdng phuang phdp quang Thiit bi sd dttng tdl, cd gid thdnh thdp, phd hgp vdi dieu kiin trang bi cda ca sd cung nhuxu the sd dung chung cua cdc nude hiin Abstract: Calibration of vertical cylindrical tanks basing on optical-reference line method has been applying for recent years by the Volume and Flow laboratory of Vietnam Metrology Institute This report presents Ihe process of study and improvement some simple theodolites to set up a optical reference line device (a precision engineer's theodolite with a pentaprism attachment) This instrument is useful because of low price, conformable to condition of measuring equipment as well as Ihe trend of development in some coulries currently I MUC DICH Bfi tilt dttng la phuong tifin do, chtta va giao nhdn rdt phfi bifin ttt miflc dfin nay, dac bifit Id Uong nghanh xdng ddu, hod chdt, chfi bifi'n thuc phdm (Rifing Tfing Cfing ty xang ddu dang si dung trfin 300 bfi till cfl sic chttatiJ400 dfi'n 17000m3 Ufin khdp ca nttfic) Dfi lap bang dungti'chbfi tru ding, hifin ta da cfl phttong phdp hifiu chudn DLVN 130-2004 si dung nguyfin tdc dttflng quang chudn, ding mdy may ngdm quang hgc vfli nhifiu ttu difim nfii ifii vd dugc nhifiu nttflc trfin thfi gioi stt dung ttt Idu Tuy nhifin, de cfi mfit bfi thifit hi ngdm ding quang hgc ddy di thi kinh phi mua cia nuflc ngoai la kha cao, khfi cfi thfi trang bi rfing rai cho cdc don vi luflng Mat khac cdc thifit bi phu ti-g nhu xe kfio cung khfl cung khfl si dung dugc tai dieu kifin be Vifit nam Xudt phat t i thuc tfi nay, Phflng Dung tich-Luu lugng, Trang tdm luflng da cfl dfi tdi nghifin cttu cdi tifin, chfi tao dp dung bfi phuong tifin be Uu dung theo phuong phdp quang ttt vai nam truflc va da dttgc nghifim thu ttt cufii nam 2003 Phuong an cai tifi'n ndy da khdc phuc dttgc cac khfl khantifinvd cho san phdm Id bfl thiet bi bfi tru dttng theo phttong phdp quang hgc, dap ttng dttgc yfiu cdu ky thudt Thuc tfi si dung thfli gian qua cho thdy, bfl thifit bi bfi Uu ding da phdt huy hifiu qua tfit bfli nfl khflng chi ddp ing dttgc cac yfiu cdu cia DLVN 130-2004 ma cfin cfi gia thdnh thd'p, si dung thudn tifin cac difiu kifin bfi Vifit Nam Hifin bfi thifi't bj bat ddu dugc cac chi cue Ittflng vd mfit sfi don vi s i dung thay the ddn phuong phdp cu 470 II TfNH TOAN T H I I T KE Vific Idp bang dung tich bl tru dfing bao gdm vific do, tfnh thi tich ddy va thi tieh cac tdng tdn Phuong phdp cd phuong phap dung tfeb va phuong phap hinh hge Bd thifi't bi ngdm quang hgc d day chfnh la dfing cho phuong phap hinh hgc 2.1 Thiet bi dung tich day be theo phuong phap hinh hgc Do ddy bl bang phuong phdp hinh hgc la vific xac dinh dd map md cua day dl tfnh thi tfch ddy Tfi trfide tdi nay, theo DLVN 28-1998 "Bl tru dfing-Qui tnnh ldp bang dung tl'ch", chfing ta vdn phai sfi dung thudc dng thuy (hinh la) Phuong phap tuong ddi dfi thuc hifin va cd chi phf tbtfp, nhung nd cung bdc Id nhilu nhugc dilm nhu dfi dn dinh khdng cao dfi bi lan khf, mfic dge dfi thay ddi nhifit dd hoac di chuyin Thdi gian thue hien lau sai sd dge Idn tfnh bdm dinh cfia nfidc vdi dng thuy Phucfng phdp mdi sfi dung may ngdm ngang (may thuy binh) da khdc phuc cac nhugc dilm trfin Nguyfin ly nhu hinh lb Thifi't bi bao gdm mdt may ngdm thuy binh va thudc chilu cao Tai mdi dilm cdm thudc ta dgc dugc m6t gia tri Hi So sanh H, vdi dilm gdc Ho ta ed dd lech A^ Tfi ddy ta se tfnh duge dd eao day va thi tfch day Hinh 1: So sanh phuong phap day hinh hgc a) Phuang phdp d'ng thuy b) Phuang phdp ngdm ngang 2.2 Thilt bi do I€ch tang tdn Dl tfnh duge thi tfch phdn tru dfing eua bl cdn phai dugc dudng kfnh tiing tdng tdn Dudng kfnh tdng day bl se coi la gdc va dugc bdng thudc chu vi Dudng kfnh cac tdng tdn khac xdc dinh thdng qua viec dfi Ifich dudng kfnh cac tdng tOn phfa trfin so vdi tdng tdn ddy Nguyfin tdc chfnh dl duge dd leeh tdng tfin nhu sau: Theo DLVN 28-1998 dfing phuong phdp "Xe Idn va ddy dgi" (Hinh 2a): Phuong phdp bao gdm mdt ddy dgi dugc gdn vdi xe lan, xe lan chuyin dOng dgc theo dfidng sinh cua bl thi day dgi dich ehuyin theo dd nhdp nhd cua bl thi hifin trfin mfit thudc gdn nam chdm dat vudng gdc vdi day dgi chan tdng mdt Dd Ifich tdng tdn dugc xac dinh bang sd dgc su dich chuyin vao cua day dgi trfin thudc Phuong phdp cd chi phf tha'p vd tuong ddi don gian, dfi sfi dung nhung cd mdt sd nhugc dilm la dd dn dinh kem, dac bifit d cdc tdng trfin, day dgi dai vd dao dOng, gay sai sd dgc Idn Khdng duge cac bl cd dfi nghifing tai dinh Idn hoti 15 cm so vdi chdn bl (do xe khdng thi bam vao 471 bfi) Xe keo phai cfi kich thuflc, khfl'i Ifln, dfi cung cfl khfli lugng Ifln Todn bfl khfli lugng cia xe va qua dfli trgng thttflng khoang (20-^30)kg, dfi rdt vdt va si dung, dac bifit la keo ufin cac bfi cfl chifiu cao Ifln hon lOm Phugng phdp hifin da dugc thay bang phuong phap "Duflng quang chudn" (DLVN 130-2004) Nguyfin tdc cua phugng phdp ndy cfl thfi mfi ta nhu Unh 2b Theo phutmg phap ddy dgi dttgc thay bdng mflt may ngdm thifin dinh, thuflc dfl Ifich tdng tfln dugc gdn true tifip trfin xe vd chay dgc theo duflng smh cia bfi Ngttgc lai vfli phttong phap "xe Idn day dgi", phttong ngdm (coi nhtt ddy dgi) fl ddy se cfl djnh, thuflc se dich chuyfin theo xe Xe bam vao thdnh bfi bang nam cham gdn gdn bdnh xe, giip lufln tifi'p xuc thdnh bfi Thufic dttgc thifit kfi dfi lufin vufing gflc vfli phttong ngdm Cdc yfiu tfi dam bao phan dnh trung thttc dfi nhdp nhfl thdnh bfi Dfl Ifich tdng tfln se la sfi dgc ttfin thttflc qua may ngdm Phugng phap da khdc phuc dttgc nhttng nhttgc difim dugc nfiu fl phugng phap " Xe Idn ddy dgi" Dfi fln dinh cia phfip dgc cao hon va kich thuflc cung nhtt khfii Ittgng cia xe kfio giam chi cfln khoang 1/5 Tuy nhifin nfi'u s i dung ca bfifliifi'tbi ddy di cia nuflc ngodi thi phttong phdp cung khfl tiifin khai fl nttflc ta mflt sfi nguyfin nhan nhtt gia thdnh cao, xe khfi di chuyfin Uong difiu kifin bfi Vifit nam, chay khfi dam bao dflfindinh dttflng sinh, xe khflng dttgc mflt sfi vi tri dac bifit cia bfi nhu cdu thang Chi'nh vi vay cdn phai cfl giai phdp rifing phi hgp, khdc phuc cac khfl khdn Ufin, dam bao dttgc cdc yfiu cdu ky thudt dfi va cfl gia thdnh vtta phai Phuong ngam Thudc nam cham dihig y^\ ^ I Day doi a) Phuong phdp xe lan day doi b) Phuong phap du5ng quang chu^n Hinh Cac phuong phdp khao sat dfi lech tang tfin be tru dttng Phugng dn cai tien mdy ngdm thdng ding Phuong an cai tifi'n mfli tflm tdt nhu sau: Ti mfit mdy ngdm ngang, ta ldp thfim mflt lang kinh chuyfin huong nhm 90° chifiu thdng dttng dfi cfl duoc mflt mdy ngdm thdng T^'^ ffMtt^L ",^^ *"'' " " ' ' ™ '*"S '"''* ''^" '^ nhaig d^'de kifim, gid via phai van dfi khfl khan la may phai cfl kfit cdu eg vflng chdc, chinh xac dfi Idng kinh tao , r f " , l ^ ^ r * ' J ° J ™*"^ '^'"'"'' "^^ * ""*'= * ° Ph^P- D^ dat dfl chinh xdc nhu yfiu cdu I * u ^ tifin cdn chinh, may dugc thifit kfi thfim nivfi cfl dfl chmh xdc cao ddt vufing gflc nhau, dam bao cho may can bang cd hai chifiu tai mflt vi tri chudn Cdc nivfl ndy duoc cdn 472' chinh chudn trudc, ngudi sfi dung diiu chinh ni vfi dfing la ddm bao phuong ngdm cfia mdy chfnh xac pham vi cho phep Dl xac dinh dd chfnh xdc va dd dn dinh cfia may dat dugc sau da cdn chinh dung ta cd the tinh toan nhu sau (Hlnh 3) Tfi cfing thfic : tgp = a/H ta cd p = arctg(a/H) Trong dd: p: Gde Ifieh (phfiong dgi) may ngdm H: D6 eao thudc so vdi may ngdm a: Dd Ifich may ngdm dgc Nlu gia dinh sai Ifich may ngdm a = 2mm , vdi dd H = 20m => ta cd P = 21" Day cung la gdc Ifich chdp nhan dugc cua may ban ehl ve mdt gia cfing Ta cdng giam gdc may cdng chi'nh xac Ly tudng p = 10" tfic dd lech la 1:20000 Qua tinh todn va thuc tl sfi dung eho thdy, kha nang can chinh nivd eua ngudi thao tdc se dao ddng vao khoang nhd hon 20", dd sai sd eua mdy se la