Lokhu kubuka konke kunikeza izincomo zomklamo ophephile wezinhlelo zamapayipi ukuze kusatshalaliswe i-hydrogen.
I-hydrogen iwuketshezi olushintshashintsha kakhulu olunokuthambekela okukhulu kokuvuza. Luyinhlanganisela eyingozi kakhulu futhi ebulalayo yemikhuba, uketshezi olushintshashintshayo okunzima ukululawula. Lezi yimikhuba okufanele uyicabangele lapho ukhetha izinto, ama-gasket kanye nezivalo, kanye nezici zokuklama zezinhlelo ezinjalo. Lezi zihloko mayelana nokusatshalaliswa kwe-H2 yegesi yizona ezigxile kule ngxoxo, hhayi ukukhiqizwa kwe-H2, i-H2 yegesi, noma i-H2 yegesi (bheka uhlangothi olungakwesokudla).
Nazi amaphuzu ambalwa abalulekile okuzokusiza uqonde ingxube ye-hydrogen kanye nomoya we-H2. I-hydrogen iyasha ngezindlela ezimbili: ukubola kanye nokuqhuma.
ukuncibilika. Ukuncibilika kuyindlela evamile yokushisa lapho amalangabi ehamba khona ngengxube ngesivinini esingaphansi kwe-subsonic. Lokhu kwenzeka, isibonelo, lapho ifu elikhululekile lengxube ye-hydrogen-air lishiswa ngumthombo omncane wokushisa. Kulesi simo, ilangabi lizohamba ngesivinini samamitha ayishumi kuya kwamakhulu amaningana ngomzuzwana. Ukwanda okusheshayo kwegesi eshisayo kudala amagagasi okucindezela amandla awo alingana nobukhulu befu. Kwezinye izimo, amandla egagasi lokushaqeka anganele ukulimaza izakhiwo zesakhiwo nezinye izinto endleleni yalo futhi kubangele ukulimala.
Ukuqhuma. Lapho kuqhuma, amalangabi namagagasi okushaqeka adlula engxubeni ngesivinini esiphezulu. Isilinganiso sokucindezela kugagasi lokuqhuma sikhulu kakhulu kunesokuqhuma. Ngenxa yamandla akhuphukile, ukuqhuma kuyingozi kakhulu kubantu, ezakhiweni nasezintweni eziseduze. Ukuqhuma okuvamile kubangela ukuqhuma lapho kushiswa endaweni evalekile. Endaweni encane kangaka, ukusha kungabangelwa amandla amancane kakhulu. Kodwa ukuze kuqhume ingxube ye-hydrogen-air endaweni engenamkhawulo, kudingeka umthombo wokusha onamandla kakhulu.
Isilinganiso sokucindezela kulo lonke igagasi lokuqhuma engxubeni ye-hydrogen-air singama-20. Ekucindezelweni komoya, isilinganiso sama-20 singama-300 psi. Lapho leli gagasi lokucindezela lishayisana nento emile, isilinganiso sokucindezela siyanda sibe ngama-40-60. Lokhu kungenxa yokubonakaliswa kwegagasi lokucindezela elivela esithintelweni esimile.
Ukuthambekela kokuvuza. Ngenxa yokungavuthi kwayo okuphansi kanye nesisindo esiphansi sama-molecule, igesi i-H2 ithambekele kakhulu ekuvuzeni ngisho nasekungeneni noma ukungena ezintweni ezahlukahlukene.
I-hydrogen ilula ngokuphindwe ka-8 kunegesi yemvelo, ilula ngokuphindwe ka-14 kunomoya, ilula ngokuphindwe ka-22 kune-propane futhi ilula ngokuphindwe ka-57 kunomusi kaphethiloli. Lokhu kusho ukuthi uma ifakwa ngaphandle, igesi ye-H2 izokhuphuka ngokushesha futhi iphele, inciphise noma yiziphi izimpawu zokuvuza okufanayo. Kodwa ingaba inkemba esika nhlangothi zombili. Ukuqhuma kungase kwenzeke uma ukushisela kuzokwenziwa endaweni yangaphandle engenhla noma phansi kokuvuza kwe-H2 ngaphandle kocwaningo lokuthola ukuvuza ngaphambi kokushisela. Endaweni evalekile, igesi ye-H2 ingakhuphuka futhi iqoqeke kusukela ophahleni iye phansi, isimo esivumela ukuthi ikhule ibe yivolumu enkulu ngaphambi kokuba ihlangane nemithombo yokushisa eduze komhlabathi.
Umlilo owenzeka ngengozi. Ukuzishisa kuyinto lapho ingxube yamagesi noma umusi ivutha khona ngokuzenzekelayo ngaphandle komthombo wangaphandle wokuthungela. Kwaziwa nangokuthi “ukusha okuzenzakalelayo” noma “ukusha okuzenzakalelayo”. Ukuzishisa kuncike ekushiseni, hhayi ekucindezelweni.
Izinga lokushisa elizenzakalelayo yizinga lokushisa eliphansi lapho uphethiloli uzovutha khona ngokuzenzekelayo ngaphambi kokuba kushiswe lapho kungekho mthombo wangaphandle wokushisa lapho uthintana nomoya noma i-oxidizing agent. Izinga lokushisa elizenzakalelayo lempuphu eyodwa yizinga lokushisa lapho livutha khona ngokuzenzekelayo lapho kungekho i-oxidizing agent. Izinga lokushisa elizenzakalelayo le-H2 yegesi emoyeni lingu-585°C.
Amandla okushisa ngamandla adingekayo ukuqala ukusabalala kwelangabi ngengxube evuthayo. Amandla okushisa amancane amandla adingekayo ukuze kuvuswe ingxube ethile evuthayo ekushiseni nasekucindezelweni okuthile. Amandla okushisa amancane enhlansi yegesi i-H2 ku-atm eyi-1 yomoya = 1.9 × 10–8 BTU (0.02 mJ).
Imikhawulo yokuqhuma iwukugcwala okuphezulu nokuncane komphunga, inkungu noma uthuli emoyeni noma emoyeni lapho kwenzeka khona ukuqhuma. Ubukhulu kanye ne-geometry yendawo, kanye nokugcwala kukaphethiloli, kulawula imikhawulo. “Umkhawulo wokuqhuma” ngezinye izikhathi usetshenziswa njengegama elifanayo nelithi “umkhawulo wokuqhuma”.
Imikhawulo yokuqhuma kwezingxube ze-H2 emoyeni ingu-18.3 vol.% (umkhawulo ophansi) kanye no-59 vol.% (umkhawulo ophezulu).
Uma uklama izinhlelo zamapayipi (Isithombe 1), isinyathelo sokuqala ukunquma izinto zokwakha ezidingekayo kuhlobo ngalunye loketshezi. Futhi uketshezi ngalunye luzohlukaniswa ngokuhambisana nesigaba se-ASME B31.3. Isigaba 300(b)(1) sithi, “Umnikazi unesibopho sokunquma isigaba D, M, umfutho ophezulu, kanye namapayipi ahlanzekile aphezulu, kanye nokunquma ukuthi uhlelo oluthile lwekhwalithi kufanele lusetshenziswe.”
Ukwahlukaniswa koketshezi kuchaza izinga lokuhlolwa kanye nohlobo lokuhlolwa oludingekayo, kanye nezinye izidingo eziningi ezisekelwe esigabeni soketshezi. Umthwalo wemfanelo womnikazi ngalokhu uvame ukuba semnyangweni wobunjiniyela womnikazi noma unjiniyela oqashwe ngaphandle.
Nakuba i-B31.3 Process Piping Code ingatsheli umnikazi ukuthi iyiphi into okufanele ayisebenzisele uketshezi oluthile, inikeza isiqondiso mayelana namandla, ukujiya, kanye nezidingo zokuxhumeka kwezinto. Kukhona futhi izitatimende ezimbili esingenisweni sekhodi ezisho ngokusobala:
Futhi yandisa isigaba sokuqala ngenhla, isigaba B31.3. 300(b)(1) sithi futhi: “Umnikazi wokufakwa kwepayipi unesibopho sokuthobela le Khodi kanye nokusungula izidingo zokuklama, ukwakha, ukuhlola, ukuhlola, kanye nokuhlola ezilawula konke ukuphathwa koketshezi noma inqubo lapho ipayipi liyingxenye yayo. Ukufakwa.” Ngakho-ke, ngemva kokubeka imithetho ethile yesisekelo yesibopho kanye nezidingo zokuchaza izigaba zesevisi yoketshezi, ake sibone ukuthi igesi ye-hydrogen ingena kuphi.
Ngenxa yokuthi igesi ye-hydrogen isebenza njengoketshezi oluguquguqukayo olunokuvuza, igesi ye-hydrogen ingabhekwa njengoketshezi olujwayelekile noma uketshezi lwe-Class M ngaphansi kwesigaba B31.3 senkonzo yoketshezi. Njengoba kushiwo ngenhla, ukuhlukaniswa kokuphathwa koketshezi kuyimfuneko yomnikazi, uma nje kuhlangabezana neziqondiso zezigaba ezikhethiwe ezichazwe ku-B31.3, isigaba 3. 300.2 Izincazelo esigabeni esithi “Izinsizakalo ze-Hydraulic”. Lokhu okulandelayo yizincazelo zesevisi yoketshezi olujwayelekile kanye nesevisi yoketshezi lwe-Class M:
"Isevisi Ejwayelekile Yoketshezi: Isevisi yoketshezi esebenza kumapayipi amaningi ngaphansi kwale khodi, okungukuthi ayihambisani nemithethonqubo yamakilasi D, M, izinga lokushisa eliphezulu, umfutho ophezulu, noma ukuhlanzeka koketshezi okuphezulu."
(1) Ubuthi boketshezi bukhulu kangangokuthi ukuchayeka kanye kuphela enanini elincane kakhulu loketshezi olubangelwa ukuvuza kungabangela ukulimala okukhulu okungapheli kulabo abaphefumula noma abathintana nalo, noma ngabe kuthathwa izinyathelo zokululama ngokushesha.
(2) Ngemva kokucabangela ukwakheka kwepayipi, ulwazi, izimo zokusebenza, kanye nendawo, umnikazi unquma ukuthi izidingo zokusetshenziswa okuvamile koketshezi azanele ukunikeza ukuqina okudingekayo ukuvikela abasebenzi ekuvezweni.
Encazelweni engenhla ye-M, igesi ye-hydrogen ayihlangabezani nemigomo yesigaba (1) ngoba ayibhekwa njengoketshezi olunobuthi. Kodwa-ke, ngokusebenzisa isigaba esincane (2), iKhodi ivumela ukuhlukaniswa kwezinhlelo ze-hydraulic ekilasini M ngemuva kokucatshangelwa okufanele "...umklamo wamapayipi, ulwazi, izimo zokusebenza kanye nendawo ..." Umnikazi uvumela ukunqunywa kokuphathwa koketshezi okuvamile. Izidingo azanele ukuhlangabezana nesidingo sezinga eliphakeme lobuqotho ekwakhiweni, ekwakhiweni, ekuhlolweni, ekuhlolweni nasekuhlolweni kwezinhlelo zamapayipi egesi ye-hydrogen.
Sicela ubheke iThebula 1 ngaphambi kokuxoxa ngokugqwala kwe-hydrogen lokushisa eliphezulu (i-HTHA). Amakhodi, amazinga, kanye nemithethonqubo kubhalwe kuleli thebula, elihlanganisa imibhalo eyisithupha ngesihloko sokugqwala kwe-hydrogen (HE), okuyisimo esingavamile sokugqwala esihlanganisa i-HTHA. I-OH ingenzeka emazingeni okushisa aphansi naphezulu. Njengoba ibhekwa njengohlobo lokugqwala, ingaqaliswa ngezindlela eziningana futhi ithinte nezinto eziningi ezahlukene.
I-HE inezinhlobo ezahlukene, ezingahlukaniswa zibe yi-hydrogen cracking (HAC), i-hydrogen stress cracking (HSC), i-stress corrosion cracking (SCC), i-hydrogen corrosion cracking (HACC), i-hydrogen bubbling (HB), i-hydrogen cracking (HIC). )), i-hydrogen cracking egxile ekucindezelekeni (SOHIC), i-progressive cracking (SWC), i-sulfide stress cracking (SSC), i-soft zone cracking (SZC), kanye ne-high temperature hydrogen corrosion (HTHA).
Ngendlela elula kakhulu, ukubhidlika kwe-hydrogen kuyindlela yokubhubhisa imingcele yezinhlamvu zensimbi, okuholela ekunciphiseni ukubhidlika ngenxa yokungena kwe-hydrogen ye-athomu. Izindlela okwenzeka ngazo lokhu ziyahlukahluka futhi zichazwa ngokwengxenye ngamagama azo, njenge-HTHA, lapho kudingeka khona izinga lokushisa eliphezulu kanye ne-hydrogen yokucindezela okuphezulu ngesikhathi esisodwa ukuze kubhidlike, kanye ne-SSC, lapho i-hydrogen ye-athomu ikhiqizwa njengamagesi avaliwe kanye ne-hydrogen. ngenxa yokugqwala kwe-asidi, ingena ezimweni zensimbi, okungaholela ekubhidlikeni. Kodwa umphumela uwonke ufana nawo wonke amacala okubhidlika kwe-hydrogen achazwe ngenhla, lapho amandla ensimbi encishiswa ukubhidlika ngaphansi kobubanzi bayo bokucindezeleka obuvunyelwe, okubeka isiteji sesenzakalo esingaba yinhlekelele ngenxa yokuguquguquka koketshezi.
Ngaphezu kobukhulu bodonga kanye nokusebenza kahle kwamalunga okusebenza, kunezici ezimbili eziyinhloko okufanele uzicabangele lapho ukhetha izinto zesevisi yegesi ye-H2: 1. Ukuchayeka ku-hydrogen yokushisa okuphezulu (i-HTHA) kanye 2. Ukukhathazeka okukhulu mayelana nokuvuza okungenzeka. Zombili lezi zihloko zisaxoxwa njengamanje.
Ngokungafani ne-hydrogen yama-molecule, i-hydrogen ye-athomu inganda, iveze i-hydrogen emazingeni okushisa aphezulu kanye nokucindezela, idale isisekelo se-HTHA engaba khona. Ngaphansi kwalezi zimo, i-hydrogen ye-athomu iyakwazi ukusabalala iye ezintweni noma imishini yokudonsa ipayipi lensimbi yekhabhoni, lapho isabela khona ne-carbon esixazululweni sensimbi ukuze yakhe igesi ye-methane emingceleni yokusanhlamvu. Njengoba ingakwazi ukuphuma, igesi iyanda, idale imifantu kanye nemifantu ezindongeni zamapayipi noma izitsha - lokhu kuyi-HTGA. Ungayibona ngokucacile imiphumela ye-HTHA kuMfanekiso 2 lapho imifantu kanye nemifantu kubonakala khona odongeni oluyi-8″. Ingxenye yepayipi yobukhulu obujwayelekile (i-NPS) ehluleka ngaphansi kwalezi zimo.
Insimbi yekhabhoni ingasetshenziswa ekuhlinzekeni nge-hydrogen uma izinga lokushisa lokusebenza ligcinwa lingaphansi kuka-500°F. Njengoba kushiwo ngenhla, i-HTHA yenzeka lapho igesi ye-hydrogen ibanjwe ngokucindezela okuphezulu kwengxenye kanye nokushisa okuphezulu. Insimbi yekhabhoni ayinconywa uma ingcindezi engaphelele ye-hydrogen kulindeleke ukuthi ibe cishe ku-3000 psi futhi izinga lokushisa lingaphezu kuka-450°F (okuyisimo sengozi kuMfanekiso 2).
Njengoba kungabonakala ku-Nelson plot eguquliwe ku-Figure 3, ngokwengxenye ethathwe ku-API 941, izinga lokushisa eliphezulu linomthelela omkhulu ekuphoqeleleni i-hydrogen. Ingcindezi engaphelele yegesi ye-hydrogen ingadlula i-1000 psi uma isetshenziswa nezinsimbi ze-carbon ezisebenza emazingeni okushisa afinyelela ku-500°F.
Umfanekiso 3. Leli shadi likaNelson eliguquliwe (elilungiswe kusuka ku-API 941) lingasetshenziswa ukukhetha izinto ezifanele zesevisi ye-hydrogen emazingeni okushisa ahlukahlukene.
Ku-Fig. 3 kukhombisa ukukhetha kwezinsimbi eziqinisekisiwe ukugwema ukuhlaselwa yi-hydrogen, kuye ngokushisa okusebenzayo kanye nokucindezela okuyingxenye kwe-hydrogen. Izinsimbi ezingagqwali ze-Austenitic azinandaba ne-HTHA futhi ziyizinto ezanelisayo kuzo zonke amazinga okushisa kanye nokucindezela.
Insimbi engagqwali ye-Austenitic 316/316L iyinto ewusizo kakhulu ekusetshenzisweni kwe-hydrogen futhi inomlando oqinisekisiwe. Nakuba ukwelashwa kokushisa ngemva kokushiswa (i-PWHT) kunconywa ukuthi izinsimbi ze-carbon zikwazi ukugaya i-hydrogen esele ngesikhathi sokushiswa futhi zinciphise ubulukhuni bendawo ethintekile ekushiseni (i-HAZ) ngemva kokushiswa, akudingekile izinsimbi ezingagqwali ze-austenitic.
Imiphumela yokushisa okubangelwa ukwelashwa kokushisa kanye nokushisela ayinawo umthelela omkhulu ezimpahleni zemishini zezinsimbi ezingagqwali ze-austenitic. Kodwa-ke, ukusebenza ngokubandayo kungathuthukisa izakhiwo zemishini zezinsimbi ezingagqwali ze-austenitic, njengokuqina nokuqina. Lapho kugoba futhi kwakhiwa amapayipi ngensimbi engagqwali ye-austenitic, izakhiwo zawo zemishini ziyashintsha, okuhlanganisa nokwehla kokuqina kwezinto.
Uma insimbi engagqwali ye-austenitic idinga ukwakheka okubandayo, ukufuthwa kwesisombululo (ukushisa kufike cishe ku-1045°C kulandelwe ukucisha noma ukupholisa ngokushesha) kuzobuyisela izakhiwo zemishini zezinto zibe ngamanani azo okuqala. Kuzophinde kuqede ukuhlukaniswa kwe-alloy, ukuzwela kanye nesigaba se-sigma esitholwe ngemuva kokusebenza okubandayo. Lapho wenza ukufuthwa kwesisombululo, qaphela ukuthi ukupholisa okusheshayo kungabuyisela ukucindezeleka okusele ezintweni uma kungaphathwanga kahle.
Bheka amathebula e-GR-2.1.1-1 I-Piping and Tubing Assembly Material Specification Index kanye ne-GR-2.1.1-2 I-Piping Material Specification Index ku-ASME B31 ukuze uthole izinketho zezinto ezamukelekayo zesevisi ye-H2. Amapayipi ayindawo enhle yokuqala.
Njengoba inesisindo esijwayelekile se-athomu samayunithi angu-1.008 esisindo se-athomu (amu), i-hydrogen iyisici esincane kakhulu nesincane kunazo zonke etafuleni le-periodic, ngakho-ke ithambekele kakhulu ekuvuzeni, okunemiphumela engaba mibi kakhulu, nginganezela. Ngakho-ke, uhlelo lwepayipi legesi kumele lwakhiwe ngendlela yokuthi lunciphise ukuxhumana kohlobo lwemishini futhi luthuthukise ukuxhumana okudingekayo ngempela.
Uma kunciphisa izindawo ezingase zivuthe, uhlelo kufanele luhlanganiswe ngokuphelele, ngaphandle kokuxhumeka okugoqekile emishinini, ezintweni zokufaka amapayipi kanye nezinto zokufaka. Ukuxhumeka okugoqekile kufanele kugwenywe ngangokunokwenzeka, uma kungenjalo ngokuphelele. Uma ukuxhumeka okugoqekile kungenakugwenywa nganoma yisiphi isizathu, kunconywa ukuthi kuhlanganiswe ngokuphelele ngaphandle kokuvala intambo bese uvala i-weld. Uma usebenzisa ipayipi lensimbi yekhabhoni, amalunga epayipi kumele ahlanganiswe ngezinqe bese ephathwa ngokushisa ngemva kokugoqeka (PWHT). Ngemva kokugoqeka, amapayipi asendaweni ethinteke ngokushisa (HAZ) abhekene nokuhlaselwa yi-hydrogen ngisho nalapho izinga lokushisa liphezulu. Ngenkathi ukuhlaselwa yi-hydrogen kwenzeka ikakhulukazi lapho izinga lokushisa liphezulu, isigaba se-PWHT sizonciphisa ngokuphelele, uma kungenjalo, lokhu kungenzeka ngisho nangaphansi kwezimo ezizungezile.
Iphuzu elibuthakathaka lesistimu ehlanganisiwe ngokuphelele ukuxhumana kwe-flange. Ukuqinisekisa izinga eliphezulu lokuqina ekuxhumeni kwe-flange, ama-gasket e-Kammprofile (umfanekiso 4) noma olunye uhlobo lwama-gasket kufanele asetshenziswe. Njengoba yenziwe cishe ngendlela efanayo ngabakhiqizi abaningana, le pad iyathethelela kakhulu. Yakhiwe ngamasongo ensimbi ahlanganisiwe ahlanganiswe phakathi kwezinto zokuvala ezithambile neziguquguqukayo. Amazinyo agxilisa umthwalo webholithi endaweni encane ukuze anikeze ukulingana okuqinile ngaphandle kokucindezeleka okuncane. Yaklanywa ngendlela yokuthi ingakhokhela izindawo ze-flange ezingalingani kanye nezimo zokusebenza ezishintshashintshayo.
Umfanekiso 4. Ama-gasket e-Kammprofile anomgogodla wensimbi oboshwe nhlangothi zombili nge-filler ethambile.
Esinye isici esibalulekile ekuqineni kwesistimu yivalvu. Ukuvuza okuzungeze uphawu lwesiqu kanye nama-flange omzimba kuyinkinga yangempela. Ukuvimbela lokhu, kunconywa ukukhetha ivalvu enophawu lwe-bellows.
Sebenzisa ipayipi lensimbi yekhabhoni elingu-1 intshi. I-School 80 carbon, esibonelweni sethu esingezansi, uma ubheka ukubekezelelana kokukhiqiza, ukugqwala kanye nokubekezelelana kwemishini ngokuhambisana ne-ASTM A106 Gr B, ingcindezi yokusebenza ephezulu evumelekile (MAWP) ingabalwa ngezinyathelo ezimbili emazingeni okushisa afinyelela ku-300°F (Qaphela: Isizathu sokuthi “…ngokushisa afinyelela ku-300ºF…” kungenxa yokuthi ukucindezeleka okuvumelekile (S) kwezinto ze-ASTM A106 Gr B kuqala ukuwohloka lapho izinga lokushisa lidlula ku-300ºF. (S), ngakho-ke i-Equation (1) idinga ukuthi ilungise amazinga okushisa angaphezu kuka-300ºF.)
Uma sibheka ifomula (1), isinyathelo sokuqala ukubala ingcindezi yokuqhuma kwepayipi.
T = ubukhulu bodonga lwepayipi ngaphandle kokubekezelelana komshini, ukugqwala kanye nokukhiqiza, ngamasentimitha.
Ingxenye yesibili yenqubo ukubala ingcindezi yokusebenza ephezulu evumelekile i-Pa yepayipi ngokusebenzisa isici sokuphepha i-S f kumphumela P ngokwe-equation (2):
Ngakho-ke, uma usebenzisa izinto zesikole ezingu-1″ 80, ingcindezi yokuqhuma ibalwa kanje:
I-Sf yokuphepha engu-4 isetshenziswa ngokuhambisana ne-ASME Pressure Vessel Recommendations Section VIII-1 2019, Isigaba 8. I-UG-101 ibalwa kanje:
Inani le-MAWP eliphumelayo lingu-810 psi. intshi libhekisela epayipini kuphela. Ukuxhumeka kwe-flange noma ingxenye enesilinganiso esiphansi kakhulu ohlelweni kuzoba yisici esinqumayo ekunqumeni ingcindezi evumelekile ohlelweni.
Ngokwe-ASME B16.5, ingcindezi yokusebenza ephezulu evumelekile ye-150 carbon steel flange fittings ingu-285 psi. intshi ku--20°F kuya ku-100°F. I-Class 300 inomfutho wokusebenza ophezulu ovumelekile ongu-740 psi. Lokhu kuzoba yisici somkhawulo wokucindezela wesistimu ngokwesibonelo sencazelo yezinto ezingezansi. Futhi, kuphela ekuhlolweni kwe-hydrostatic, lawa manani angadlula izikhathi ezingu-1.5.
Njengesibonelo sencazelo eyisisekelo yezinto zensimbi yekhabhoni, incazelo yomugqa wesevisi yegesi ye-H2 esebenza ekushiseni okuphansi kwengcindezi yomklamo engu-740 psi. intshi, ingaqukatha izidingo zezinto eziboniswe kuThebula 2. Okulandelayo yizinhlobo ezingadinga ukunakwa ukuze zifakwe kuncazelo:
Ngaphandle kokufaka amapayipi ngokwawo, kunezinto eziningi ezakha uhlelo lokufaka amapayipi njengezihlanganisi, ama-valve, imishini yomugqa, njll. Nakuba eziningi zalezi zinto zizohlanganiswa ndawonye ukuze zixoxwe ngokuningiliziwe, lokhu kuzodinga amakhasi amaningi kunalawo angafakwa. Lesi sihloko.