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Chng 4 K THUT AN TON TRONG C KH, THIT B CHU P LC V THIT B NNG

4.1. K thut an ton trong c kh 4.1.1 Khi nim v vng nguy him trong cc thit b c kh Vng nguy him l khong khng gian trong , cc yu t nguy him i vi sc kho v tnh mng ca con ngi c th xut hin mt cch thng xuyn, theo chu k hoc bt ng. Tu theo ngnh ngh v qu trnh cng ngh m vng nguy him c th bao gm: + Khng gian c nhng b phn chuyn ng nh cc b truyn bnh rng, bnh ai, cnh qut, my khuy, bng ti, c bit nguy him i vi cc b phn quay nhanh m bn ngoi li lm, khng c dng trn xoay nh cc khp ni, g trn my tin, Nhng b phn c chuyn ng khc. + Khng gian xut hin cc vt mt cch bt ng nh c cc mnh dng c ct, vt liu chi tit gia cng, mnh v mi, + Khng gian nguy him v nhit t vt c nhit cao: Khng gian ni c kim loi: kim loi lng b vng bn khi vn chuyn, khi rt, khi c trn nn xng c nhiu hi nc,Vt nng khi rn, dp b vng ra, + Khng gian nguy him v in: Vng c in p cao hoc c th b chm in ra v thit b, 4.1.2 Nhng nguyn nhn gy ra s c, tai nn khi s dng my v thit b a) Cc nguyn nhn do thit k La chn vt liu khng ph hp vi yu cu lm vic v tnh tnh ton bn khng ng. Khng c cc c cu an ton trnh xy ra s c hoc khng c c cu che chn bo v ngi lao ng. b) Cc nguyn nhn do ch to, lp rp khng chnh xc. Dng nhm vt liu hoc sai c tnh, khng m bo kch thc so vi thit k,Lp rp khng chc, kn hoc khe h qu ln, c) Do bo qun v s dng Tai nn v s c ch yu l do nguyn nhn ny gy ra Bo qun khng tt lm h hng cc chi tit b phn c bit nguy him khi cc c cu an ton, c cu ch bo, c cu iu khin lm vic sai lch hoc khng hot ng.
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Do s dng: Lm ba, lm u, khng kim tra thng xuyn pht hin h hng v khng kp thi iu chnh sa cha hoc thay th, 4.2. K thut an ton i vi thit b chu p lc 4.2.1 Khi qut v thit b chu p lc Cc thit b dng tin hnh cc qu trnh nhit hc, ho hc cng nh dng cha, vn chuyn, bo qun cc cht trng thi c p sut cao hn p sut kh quyn. Theo k thut an ton, nhng thit b lm vic vi p sut t 0,7 kG/cm2 tr ln c coi l thit b chu p lc. Cc thit b chu p lc c phn loi ch yu theo nhit lm vic v gm hai loi: Cc thit b t nng v cc thit b khng b t nng. a) Cc thit b t nng Ni hi v cc b phn ca n (bao hi, ng dn hi), ni chng ct, ni hp,p sut c to ra l do hi nc b un qu nhit (trn 100oC) trong bnh kn. b) Cc thit b khng b t nng Bao gm nhiu loi khc nhau: - Thit b (my) nn kh: ht khng kh v nn li vi p sut cao. - Thit b s dng kh nn. - Bnh cha cc cht kh: cha xy, nit, hydr, axtylen, - Cc ng dn mi cht c p sut cao nh ng dn hi, kh t. - Cc thit b chu p lc nu b n, b v s gy ra tc hi rt nghim trng nn c yu cu nghim ngt v an ton lao ng. 4.2.2 Nguyn nhn gy ra s c i vi thit b chu p lc Cc thit b p lc b n v khi bn ca n khng chu ni tc dng ca p sut mi cht trong bnh. C hai dng n: n l hc v n ha hc. N ha hc c mi nguy him gp nhiu ln do qu trnh gia tng p sut trc khi thit b b ph hy din ra rt nhanh v p sut n ln hn nhiu ln p sut ban u trong thit b. Hin tng n ha hc c th xy ra ta nhiu im ca thit b, cn n l hc ch lm v thit b ti khu vc km bn nht ca thit b. 4.2.3 Yu cu v cc bin php an ton i vi thit b chu p lc - Chp hnh cc quy phm v vn hnh cc thit b chu p lc (c ti liu k thut v thit b, phi c h s ng k ti c quan thanh tra k thut an ton). - Trn tt cc cc thit b p lc phi t p k o p sut trong bnh. p k phi chnh xc, thng dng loi 2 kim trong mt kim ch p sut thc, cn kim kia ch p sut ln nht m thit b tng lm vic.
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- S dng cc van an ton phng nga qu p. - Thc hin ch to v sa cha theo ng quy phm, thc hin quy phm v an ton phng chng chy n. - Thng xuyn khm nghim, kim tra nh k gim st vic thc hin quy phm v an ton lao ng (bnh p lc 3 nm khm nghim mt ln, 1 nm th p lc mt ln). - Trang b cc thit b kim tra hin i v c cu van an ton. Trn tt c cc bnh phi t p k bit p sut trong bnh. - o to, hun luyn cng nhn vn hnh my v k thut an ton. 4.3. K thut an ton thit b nng Thit b nng l nhng thit b dng nng, h ti nh bc, xp hng ho kho tng bn bi, lp t thit b my mc, nng h thng kim loi lng, tho lp vn chuyn chi tit gia cng, Thit b nng gm cc loi chnh: - My trc. - Xe ti chy trn ng ray trn cao. - Pa lng in, th cng. - Ti in, th cng. - My nng. 4.3.1 Nhng s c, tai nn ch yu xy ra thit b nng a) Ri ti trng Ri ti trng c th xy ra mt trong cc trng hp sau: - Nng qu ti lm t cp nng cn, cp buc ti, mc treo ti (y l nhng trng hp ch yu). - Khi nng ti hoc quay cn b vng vo cc vt xung quanh. - C cu phanh b hng, m phanh b mn qu quy nh, mmen phanh qu b. - Dy cp b mn hoc s si b t qu tiu chun cho php, mi ni dy cp khng m bo chc chn. b) Sp cn y l s c xy ra nhiu hn c v thng gy ra cht ngi, cc nguyn nhn chnh gy ra: - Ni cp khng ng k thut. - Phanh b hng. - Cu qu ti v tr xa nht lm cp chng cn b t.
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c) cu cu c th xy ra trong cc trng hp sau: - Vng t t cu khng n nh, t b ln hoc mt bng c gc nghing qu tr s cho php. - t my gn dc hoc ho h su lm t b sp. - Cu qu ti hoc vng vo vt khc. - Mt s trng hp do vi phm ni quy an ton nh dng cu nh cy hoc mc cc kt cu b vi di t. d) Tai nn in - Thit b nng c in chm v. - Cn cu chm vo ng dy c in hoc b phng h quang do vi phm khong cch an ton in. - Thit b nng dp cp mang in. - Vi phm cc bin php k thut an ton 4.3.2 Yu cu an ton i vi mt s chi tit c cu quan trng 4.3.2.1 Cp Cp l chi tit rt quan trng ca bt k thit b nng no. Cp phi c kh nng d un, bn ko cao, chu mi mn, chu nhit tt ng thi cc si nh cng phi c cng nht nh,Dy cp c tiu chun ho v thng nht ho. a) Chn cp Cp c chn theo cc yu cu c bn sau y: - Chn theo h s an ton K, phi tho mn cng thc:

P K S
Trong : P lc ko t cp. S Lc ko ln nht tc dng ln cp trong qu trnh lm vic. K h s an ton ph thuc vo loi thit b, cng dng v ch lm vic. V d cp chng cn K = 3,5 ; cp nng ti K = 5 6 ; cp ca thit b nng ngi K = 9. - Chn kt cu ca cp ph hp vi chc nng lm vic, bao gm: chn ng knh ca cp, chn si nh, chn cp con v chn chiu xon.

- Chn chiu di cn thit. Vi cp buc ti phi m bo gc to bi cc nhnh dy 90o , cp ca c cu nng h khi lm vic v tr gii hn vn cn mt s vng d tr trn tang theo yu cu, b) Loi b cp Trong qu trnh lm vic cp b h hng dn nh b mn, b xy ho, b gy, b t dn cc si nh,Ngoi ra cn c th b dp, b tht nt v vy phi tin hnh kim tra thng xuyn, i chiu vi tiu chun kp thi loi b cp trc khi b t. 4.3.2.2 Xch Chn xch cng tng t nh chn cp. Loi b xch khi mt xch b mn qu 10% ng knh ban u. 4.3.2.3 Tang v rng rc Chn ng knh ca tang v rng rc theo cng thc: D d(e 1) Trong : D - ng knh ca tang, rng rc (mm). d - ng knh ca cp (mm). e h s ph thuc vo loi thit b v ch lm vic. V d cc thit b nng, h c ti trng trung bnh th e = 25. Chn kt cu hnh hc v vt liu ca tang, rng rc ph hp vi yu cu lm vic. Loi b tang v rng rc khi b v, b rn nt hoc b mn su qu 10% ng knh ca cp. 4.3.2.4 Phanh Hu ht cc c cu ca thit b nng u c phanh. Phanh c hai nhim v: + Ngng chuyn ng. + Hn ch vn tc ca c cu. Phanh c th phn loi theo nhiu cch khc nhau. Theo nguyn l lm vic chia thnh hai loi: phanh thng ng v phanh thng m. Theo cu to chia thnh bn loi: Phanh m, phanh ai, phanh cn , phanh a. Theo ngun dn ng chia thnh: Phanh c, phanh in, phanh thu lc, phanh kh nn. a) Chn phanh Chn tr s mmen ma st theo cng thc:

MP KP Mt
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Trong : MP mmen ma st sinh ra khi phanh. MT mmen trc cn phanh. KP h s d tr, ph thuc vo dng chuyn ng v ch lm vic KP = 1,5- 2,5. b) Loi b phanh Phanh phi c loi b khi xy ra mt trong nhng hin tng sau: + i vi phanh m: - M phanh mn khng u. - M phanh m khng u. - M phanh mn ti vt gi m phanh. - Bnh phanh b mn su qu 1mm. - Phanh c vt nt, rn. - Gc tip xc gia m phanh bnh phanh < 80% gc quy nh. - Khe h gia m phanh bnh phanh ln qu tr s quy nh. + i vi phanh ai: - C vt nt trn ai phanh. - Bnh phanh b mn qu 30% chiu dy. - ai phanh mn khng u hoc mn qu 50% chiu dy ban u. - Gc tip xc gia ai phanh bnh phanh <80% gc quy nh. - Khe h gia ai phanh bnh phanh nm ngoi khong (2-4)mm. Phanh cn v phanh a c th sa cha iu chnh trong qu trnh s dng. 4.3.3 Danh mc cc thit b an ton ca thit b nng - Thit b khng ch qu ti. - Thit b hn ch gc nng cn. - Thit b hn ch hnh trnh xe con my trc. - Thit b hn ch gc quay. - Thit b chng my trc di chuyn t do. - Thit b hn ch cao nng ti. - Thit b o gc nghing ca mt bng t my trc v bo hiu gc nghing ln qu tr s cho php. - Thit b bo hiu my trc i vo vng nguy him ca ng dy ti in. - Thit b o gi v tn hiu thng bo khi gi t ti vn tc gii hn quy nh.
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- Thit b ch tm tng ng vi ti trng cho php. 4.3.4 Khm nghim thit b nng Tt c cc thit b nng u phi tin hnh khm nghim bt buc theo k hoch t ra t trc. 4.3.4.1 H thng khm nghim Vic khm nghim c tin hnh theo hai h thng: khm nghim trc khi s dng v khm nghim nh k. a) Khm nghim trc khi s dng H thng ny c thc hin i vi cc trng hp: - My mi sn xut. - My mi lp t xong. - My sau khi sa cha. b) Khm nghim nh k L khm nghim theo chu k thi gian lm vic c nh trc. 4.3.4.2 Ni dung khm nghim - Kim tra bn ngoi: kim tra s y , s ton vn ca cc chi tit v b phn bn ngoi. - Th khng ti: tin hnh cho tt c cc chi tit v b phn hot ng khng c ti trng. - Th ti tnh: treo ti tnh bng 125% ti trng lm vic cho php v tr bt li nht trong thi gian 10 pht sau h xung kim tra pht hin h hng v bin dng. - Th ti ng: cho my lm vic vi ti trng bng 110% ti trng lm vic cho php ln cao 1 mt, h xung ri phanh t ngt, thc hin ba ln. - Th c cu nng cn, c cu quay cn v c cu di chuyn: cng t ti trng bng 110% ti trng lm vic cho php, cho cc c cu hot ng ri phanh t ngt, thc hin ba ln.

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