PETROVIETNAM Cong nghe boc chong dn mon cho cac duong ong ddu khi tgi Nhd mdy boc ong PVID Hien trgng vd cdc cai tien, hgp ly hoa ddy chuyen cdng nghe TS Chu Chit Chfnh, KS Tran DCTc Minh, ThS NguySn[.]
Trang 1Cong nghe boc chong dn mon cho cac duong ong ddu khi tgi Nhd mdy boc ong - PVID: Hien trgng vd
cdc cai tien, hgp ly hoa ddy chuyen cdng nghe
TS Chu Chit Chfnh, KS Tran DCTc Minh, ThS NguySn PhUdrc Toin
Cdng ty CP Ddu tU vd Xdy Idp khi (PVID)
Nhd mdy Bgc dng Ddu khi f trift thude Cdng ty CP Odu tU vd Xdy idp khi - Tdng edng ty Khi Viet Nam - CTCP) id nhd mdycakhibge dng ddu khi ddu tiin tgi Viit Nam Cdng tdc chi tgo, Idp ddt, chgy thd ddy chuyen mdy mdc thiit
bi Nhd mdy do nhd thdu chinh - Tdp dodn Bauhuis international B.V cua Hd Lan thuc hiin Ban ddu, Nhd mdy dUgc trang bi hai ddy ehuyin thiit bj tlin tiin, hiin dgi nhd't trin thi gidi, dd id ddy ehuyin ddng bd bgc chdng dn mdn eho cdc dudng dng, sd dung phuang phdp bgc ba Idp 3LPE/PP (Poiyethylene/Polypropylene) kit hgp vdi Idp Idt FBE (Fusion Bonded Epoxy) vd ddy chuyin dong bd bgc bi tdng gia tdi cho dudng dng, dugc sddgng cdng nghi phun vdng (Impingement) liin tgc ed lUdi thip gia cUdng cho bi tdng, cho ede logi dng cd dudng kinh tU6-48 inch, edng sudt trung binh trong diiu kiin Idm viic mdt ea Id 240km dng bge/ndm [1], Ndi dung bdi bdo gidi thiiu vi hiin trgng cdng nghe bgc chong dn mdn 3 Idp tgi Nhd mdy Bgc dng Ddu khi, sUcdn thiit phdi nghien cdu dixudt d^g dgng gidi phdp ddy ehuyen cdng nghi bgc 5 idp tgi Nhd mdy vd gidi thieu tdng thi ddy chuyen cdng nghi bgc 5 Idp do PViD dixuat nghiin cdii, thiet kevd Idp ddt tgi Nhd mdy Bgc dng Ddu khL
Gidi thieu chung
Hien nay, t r l n the gidi thudng sd
dung pho b i l n 3 phUdng phap bpc
chdng i n mdn cho dudng dng gdm:
phUPng p h i p bpc Asphalt Enamel
(AE), phuong p h i p bpc Fusion
Bounded Epoxy (FBE) va phuang
phip bpc 3 Idp Polyethylene/
Polypropylene (3LPE/PP) ket hpp vdi
Idp Idt FBE Phuang p h i p bpc AE d i
cd t d k h i l i u va l i phuang phap bpc
chdng i n mdn phd bien nhat trong
thap n i l n 60 - 80 cua the ky XX, tuy
nhien d i n nay, phUong p h i p n i y
hau nhu khdng cdn dugc sd dung
d cic nudc p h i t trien Nguyen n h i n
bdi chi phi bpc AE.phu thupc n h i l u
vao g i i dau md; dudng ong bpc AE
cung ed ehi phi t h i l t ke, bao tri Anode eao hPn trong khi
tudi thp t h i p han so vdi eac phuang p h i p bpc t i l n tien
khac; hPn nda AE edn dMc xac djnh l i v i t lieu g i y t i e
hai ddi vdi moi trUdng v i nhieu nUdc khdng cho phep sd
Hinh I.Sodo tong the ddy chuyen cong nghe boc chong dn mon va boc be tong Nhd mdy Bgc dng Dau khi
dung loai vat lieu nay trong bpe ong Phuang phap bpc chdng i n mdn duac trien khai tai N h i m i y Bpc dng Dau khi cda PVID la phuong p h i p bpc 3 Idp Polyethylene/ Polypropylene ket hpp vdi Idp Idt FBE Day la edng nghe
Trang 2mdi n h i t h i l n nay, dang dUpc sd dyng rdng r i i t r l n t h i
gidi Sa bd v l h i thdng bpe cic Idp tai N h i m i y g6m:
H I thdng bpc mdt Idp (Mono-layer system) g6m
Idp Idt Fusion Bonded Epoxy (FBE), d i y 60 - 750|jm
H I thdng bpe 2 Idp (Dual-layer system) gdm Idp
Dual Fusion Bonded Epoxy (DFBE), d i y 300 - 750|im
- H I thdng bpc 3 Idp (Polyolefin's three-layer system)
gdm Idp Polyethylene (PE)/Polypropylene (PP), chilu d i y
t d 1,5-20mm PE/PP
- DUdng kinh 6ng bpe 4 - 48 inch
Chilu d i i mdi dng 8,5 - 12,2m
SP dd tdng t h i d i y ehuyin edng n g h i bpc ehdng i n
mdn v i boe b l tdng N h i may Bpc 6ng DSu khi dUpc t h i
h i l n t r l n Hinh 1 [2]
1 Hien trang cdng nghe boc ch6ng i n mdn tai PVID
1.1 Gidi thiiu tdng thi ddy chuyin bgc 3 Idp
H | thdng boc chdng an mdn la mdt d i y chuyen ban
t u d d n g lam nhilm vu bpc cae Idp chdng an mdn FBE v i
Idp PE/PP de b i o v l mat ngoai ong n h i m chong tac dpng
ca hoc eho Idp FBE (5ng tran (bare pipes) dupc dUa vao
he thdng bpc b i n g xe nang va eie b i n g chuyen ehuyin
dung Tai eie bang chuyen, ong se dupe di chuyen,
nang/ha qua eac bang ehuyen v i gidi han hanh trinh cda
ong nhd eie can ning/ha va cic t h i l t bj ddng dng d i n
ddng bang cic md to va xy lanh thCiy luc
Trudc khi bpc, dng dupc dua v i o khu vUe lam sach
b i n g phuang p h i p phun nudc cao i p de rda sach d i t ,
bui b i m t r l n ong trong q u i trinh b i o q u i n v i v i n
c h u y i n dng t r i n v i g i i m ndng dd mudi cd t r l n b l m i t
dng ( n l u ed) Sau dd ong dupe l i m ndng so bd
(Pre-heating) b i n g khi dot (LPG) trudc khi chuyin vao l i m
sach be mat ngoai b i n g phuang p h i p phun bi (blasting)
d l tang do b i m dinh gida b l mat dng v i Idp san chong
an mdn FBE Sau khi dng dupe b i n Blasting, bd p h i n
kiem tra chat lUpng s i n pham (quality control - QC) s i
t i l n hanh c i c budc kiem tra nhU sau: k i l m tra nong dd
mudi (salt test), hinh d i n g (profile) b l mat dng, dd byi
(dust test) Kiem tra b i n g m i t thudng cae k h u y l t t i t
tren b l mat dng ( n l u cd k h u y l t t i t , se t i l n hanh sda
chda dng)
Sau dd ong dupc gia nhiet c i m dng (induction coil)
den khoang 220 - 245°C Tai eac edng doan bpe ba Idp (3L)
gom: ldp FBE (Idp son chong an mdn), Idp Adheshive (Idp
keo l i l n kit) v i ldp PE-PP (Idp dun q u i n - topcoat), c^c nguyin l l | u n i y t d cic m i y dUpc phun/dCin v l phia dng
trong khi 6ng dugc xoay trdn v i di chuyin tinh tiln vg
phia trUdc Sau cic edng doan boc, 6ng se dupc lim mit
b i n g nudc v i k i l m tra khuylt t i t n h i m p h i t h i l n nhdng
k h i l m khuylt t r l n Idp bpc d l t i l n h i n h sda chda, hoan
t h i | n cdng do?n bpc chdng i n mdn
04 thye h l | n tdt v i d i m b i o c h i t lUpng k i t qui quS
trlnh bpc 3 Idp, h i thdng d i y ehuyin cdng n g h i bpc 3L duac trang b| cic t h i l t bj do, dupe l i p d i t ngay tai cic
m i y d mdi cdng doan chinh n h i m k i l m tra v i hien thi cie thdng sd c i n k i l m soit trong sudt q u i trinh bgc Ddng thdi, PVID bd tri ddi ngu QA/QC true t i l p kilm tra
c h i t lupng s i n p h i m tai mdi cdng doan cda q u i trinh bpc n h i m d i p dng y l u c i u c h i t luang d i t ra theo yeu
c i u ky t h u i t cda mdi d y i n Tai m6i edng doan, cic ky su/cdng n h i n ky t h u i t v i n h i n h v i g i i m s i t q u i trinh bpc d l kjp thdi p h i t h i l n / x d ly nhijmg b i t thudng (neu
x i y ra) trong q u i trinh s i n xuat Hinh i n h tdng the hifei trang day ehuyin eong nghe bpc ehdng i n mdn cho cac dudng dng tai N h i m i y Bpc ong D i u khi dupe the hiln
t r l n Hlnh 2
Trang 31.2 Cdc logi cdng nghi bgc 3 Idp
Ve cdng nghe bpc chdng an mdn 3 Idp hien nay d i u
theo mpt nguyin ly chung nhU sau: dng dupe gia nhiet
den n h i l t dd thich hpp, sau do dupc dua qua bpc cic Idp:
Ldp 1: FBE - Phun tmh d i l n
- Ldp 2: Adhesive - Phun bdt hoie extrusion (tdy
theo dp day)
Ldp 3: Topcoat - Ddn q u i n PE/PR
V I edng nghe bpe Idp thd 2 (Adhesive), phd b i l n ed 2
loai edng n g h | boc: cdng n g h i bpc dung h i thdng sung
phun (Spray gun) va edng n g h i boc dung h i thdng dun
(Extrusion)
1.2.1 Cdng nghi boc dung hi thong dim (Extrusion system):
Uu diem:
-i- Cdng suit cao, thich hpp cho Idp bpc day;
+ Tinh on djnh cao
Nhupc diem:
-I- Khd kiem soit chieu day Idp bpe;
+ Dp bam dinh gida eie Idp khdng eao
1.2.2 Cong nghe boc diing he thdng sung phun (Spray gun):
Uu d i l m :
+ Gpn nhe, cd the l i p dat trong khong gian nhd;
+ Oe k i l m soit chilu day Idp bpe, thich hap cho eie
Idp boc c6 chieu d i y < 1 mm;
+ Dp bam dfnh gida eie Idp eao;
-I- J^ le ong bi Idi eua ldp bpc thap
Nhupc diem:
+ Dd bui t h i i ra ngoii moi trudng eao;
+ Gii thanh cao han
Sa dd quy trinh bpe 3 Idp (3 Layer application pocess) duac t h i h i l n t r l n Hinh 3
2 Cac noi dung c i i t i l n day chuyen cong nghe hoc chdng an mdn 31
2.1 Cdc ddc diim ehUa phu hgp cua ddy ehuyin cdng nghi bgc 3L
Cdng suit eua may dun nhd (extruder) diJng cho bpe adhesive, khdng dd de dung cho bpc topcoat cda 5LPP Do chlnh lech d i u ra v i d i u v i o khi bpe 3LPE/3LPP
la khoing 5mm, nhUng ddi vdi bpc 5LPP la khoing 10 -15mm
H | thdng b i n g ehuyen khdng phd hap de bpc Idp day t r l n 12mm
- He thdng l i m mat khdng dd d i p dng cho Idp bpe day
H I thdng cap l i l u chua phu hpp cho vile bpe vat lieu nhilu t h i n h phin
Roller bpc (Applycation roller) khdng dd dp mem
de tao Idp boc cd ty trpng thap
Thilu he thdng gia nhiet ben ngoai Idp bpc Thilt bi cut-back khdng tao dupe bac (PP Toe) tai doan cut-back eda 2 d i u dng (phuc vy cho cdng t i e bpe mdi h i n tai edng trUdng)
2.2 Cdc noi dung PVID dixudt vd dd edi tiin
- Lap d i t m i y dun mdi vdi edng suit Idn hon de bpc
Topcoat
Thiet k l , c i i t i l n he thdng bang chuyen, cd t h i
d i l u chlnh linh hoat theo chieu day Idp bpe
Ndi d i i h i thdng lam m i t
Bo sung them h i thdng lam m i t ben trong ong (internal quench)
Lip d i t t h i m miy tron vat lilu v i o he thdng cap lilu
B9C Idp chfing in mdn
Hinh 3 Sado quy trinh boc 3 Idp (S Layer application pocess) tgi Nhd mdy Bgc ong Ddu khi
Trang 4Gia cdng roller bpe (Applycation roller) cd dd cdng
t h i p
T h i l t ke, l i p d i t cP c i u gia nhi|t hdng ngo^i
T h i l t k l , l i p d i t t h i m m i y cut-back 5LPR
3 SU cSn t h i e t p h i l n g h i l n cihj, d l xujft g l i l p h i p d i y
c h u y i n cong n g h i boc 5 Idp
Do mdi tham gia v i o thj trudng bpc dng trong vdng
2 nam g i n diy, PVID da ehju nhdng i p li/c n h i t djnh khi
tham gia d i u t h i u trye t i l p vdl cic doanh nghi|p bpc
dng h i n g d i u t r l n t h i gtdi Diy chuyin bpe 3 Idp l i d i y
chuyin chl dung d l bpc chdng i n mdn b i n g FBE mdt Idp
hay n h i l u Idp hoic boc 3 Idp PE/PP (FBE + Adhesive +
PE/PP).Tuy nhiln, t r l n thye t i c h u d i u t u m d t sSdUin ddi
hdi khong chi ein sin p h i m bpc chdng i n mdn m i cdn
boc cich n h i l t (bio dn) eho dudng dng, d i e b i l t p h i i d i p
dng cic d i l u k i l n khie nghilt nhU: chiu duoc n h i l t dd
cao khi v i n h i n h (tdi 150'<:), ehju dupc i p lUc b i n ngoii
eao (tuyln dng dupc l i p dat d khu vUe nude siu hoic r l t
sau) nen y l u c i u p h i i boe 5 Idp PP (5LPP) D i y l i mdt loai
bpe each nhiet cd cdng n g h i r i t phdc tap v i thi edng khd
khan, ke ea ddi vdi eie n h i m i y boc dng t r l n the gidi d i
cd hang chyc nam kinh nghilm
Do y l u cau thuc t l va can p h i i da dang hda sdn pham,
PVID d i de xuat n h i l m vu nghiln cdu, t h i l t k l v i l i p d i t
d i y chuyen cdng nghe bpc ong 5 Idp tai N h i may Bpc dng
Dau khi n h i m hpp ly hda day ehuyin cdng nghe hien ed
va bo sung day chuyin cdng nghe mdi Trong qua trinh
trien khai thye h i l n N h i may da eung hop tac vdi doi t i c
nude n g o i i de c h l tao v i cai h o i n n h i m d i m b i o d i y
chuyen cdng n g h i boc 5 Idp dPn g i i n hpp 1^ v i tiet k i l m
ehi phi
4 D i y chuyen cong nghe mdi bpc 5 ldp dugc l i p d i t
tai Nha may boc ong PVID
4.1 Tdng quan vi ddy chuyin
D i y ehuyin edng n g h i bpe 5 ldp do PVID cung ddn
vj t u van nude ngoii tU nghien cdu, t h i l t k l v i l i p d i t ,
bao gdm tat c i cic h i thong, cdng doan d l tao ra mdt
sin pham bpc dng 5 Idp 5LPP h o i n t h i l n Day ehuyin n i y
dupc n g h i l n cdu, t h i l t k l hpp \^ v i s i n g tao v l b5 tri cic
t h i l t b| d i y chuyin, chpn Ida cic t h i l t bj, d i l u ddng linh ho?t cic t h i l t b| nhu: h | thdng b i n g chuyin linh hoat, c6
t h i d i l u chinh tdc dO, b l r^ng d l phu hpp vdi d i l u k U i
m i t b i n g , n h i xudng h l | n tai cda N h i m i y v i vdi chi phi
t h i p n h i t
Diy chuyin cdng n g h | bpc 5 Idp bao gdm cic bd
p h i n , t h i l t bj chlnh:
+ H | thdng 2 m i y dCin vdi cdng suit 1.200kg/gidvi 750kg/gid
+ H | thdng b i n g chuyin linh ho?t, cd t h i dilu chlnh tdedd, b l r ^ n g p h d h p p v d i b p c 5 L P R
+ Ca c i u c i p l i l u vdi t^ I I pha tr^n chinh xic dSt
0,02% ^
•f- Cym m i y cutback dupc t h i l t k l gpn nhe phiJ h m vdi m i t b i n g d i y chuyin vdl tfnh h i l u q u i cao I
+ Tram nude l i m m i t dupc t h i l t k l vdi cdng sultlifit,
d i p dng dupc y l u c i u eua edng n g h | bpc 5 ldp
4.2 Kit qud chgy thiSrnghiim ddy chuyin cdng nghi bgc SIdpSLPP
+ TJ" trpng 6n djnh dat 650 - 660 kg/m' tai dau ra vdi
ty I I pha trdn c h i t tao bot kht trong PP (blow agent) la 1,7%
+ Chilu d i y mdt l i n bpe datdude 15-17mm Ung vdi tdc dd chay dng 0,4n)/phut n h u v i y d6i vdi dng bpc 5LPP
d i y 65mm se bpc 4 l i n + Tram nude l i m m i t cd h i l u q u i tdt, l i m giim nhiet
d ^ Idp bpc xudng dUdi 60<<:
+ Thilt bi cut-back d i v i n h i n h t h i n h cdng vdi may
m i l ch6i (Brushing cutback)
Vdi k i t q u i chay t h d nghiem d i y chuyin cdng nghi bpe 5LPP t h i n h cdng nhu neu tren, PVID cd t h i khing djnh N h i m i y bpe dng hoan t o i n d i p dng dupe ylu cau cua cic d u i n bpc 6ng 3 Idp v i 5 Idp, d i m b i o chit iUpng cung nhu t i l n dp eda s i n p h i m v i cda cie d y an Chi tiet
k i t q u i t h d n g h i l m d i y chuyin 5LPP dupe n l u chi tiet trong Bing 1
Loai ong
12 inch
Bdng 1 Bdng thdng s6 kit qud thd nghifm ddy chuyin 5LPP
Tdc dd bdng t i i TScddmiydCin Ap suit m i y dun
130s/m 1 SORpm j 6,8Mpa
Khdi IUdng vat lilu/phdt 7-8kg
Chilu d i y Itfp boc
13mm
Trang 5Mdt s6 hinh anh cda day chuyin 5 Idp dang boc 6na cho DA BDl/CRA'
Ong dUa vdo ddy chuyin qua hi thdng gla nhiit bimdt bang tia hdng 6ng sau khi bgc PP dugc chuyen qua khu vUc Idm mdt ngogi tn/dc khi di qua hi dng bgc extrutlon, sau do dUac Idm mdt
5 Mot so sin pham boc chong an mon 3 Idp va 5 ldp da thUc hi^n tai PVID (Bang 2)
Bdng 2 Mdt sd sdn phdm boc chdng dn mdn 3 idp vd 5 Idp dd thuc hiin tai Nhd mdy boc ong PVID
TT
1
2
3
4
-6
7
8
9
10
Nam htfp ddng I
Htfp dong ChO dau tu Tinh trang AM tht h-' Yeu cau ky thuat boc
Duan HaiSUTr3ng PVGas Hoanthanh ! 13/11/2011
Te Giac Tring
RC5 -1- RC6 & RC7
Su TCr Trang
! 1 Hoang Long JOC ! Hoan thanh 27/1/2011
Vietsovpetro Hoanthanh ; 15/7/2011
Cuu Long JOC Hoan thanh ; 25/2/2012
»'"'^°"9==*°"|BDPOC/PTSCM&C
steel project
Duan dudng ong
xuat khau khf Bien
Ddng NCSP2
BK14-VSP
MTC1 -VSP
Bien Dong clad
pipes project
Duan Hii SUTring
-HaiSUDen
PTSC M&C
Vietsovpetro
Vietsovpetro
BDPOaPTSC M&C
Thang Long JOC
Hoan thanh
Hoan thanh
Hoan thanh
Hoanthanh
Bang thUchien
Dang thuc hien
28/2/2012
28/3/2012
24/3/2012
28/4/2012
Line pipes coating (3LPE -t- CWC)
0,7mm FBE + 53,2mm PUF +
5mm HOPE + SOmmCWC
FBE, PU FOAM, HOPE and CWC
3Smm5LPP +58mm CWC
3mm 3LPE + 40mm CWC
3mm3LPE + 40mmCWC
3mm3LPE-l-40mmCWC 0,5mm FBE + 30,0mm PUF -i-5mmHDPP+40mmCWC
65mm 5LPP +40mm CWC
0,5mm FBE -H 32,2mm PUF+
5mmHDPE-i-40mmCWC
Ghi chu
12 inch, 28km 6,8,10 &
12 inch, 36km
8 & 10 inch, 15km
12 inch, 20km
20 inch, 46km
26 inch, 4km
8 inch, 6km
12 inch, 10,8km
12 inch,
i-20,8km 1 6,8,10 & 1
12 inch, 36km 1
Trang 6Mdt sd hinh i n h cic lo?i sin p h i m bpe ehdng i n mdn 3 Idp v i 5 ldp da thdc h i | n t^i PVID
•nj iil'l IJUdnlcdidr Trdng Irdng/HdiSuDen
6 Kdt luin
1 Diy chuyin ddng bd bpe chdng i n mdn cho cic
dudng dng, sddyng phUPng p h i p bpc 3 Idp 3LPE/PP k i t
hpp vdl Idp Idt FBE dupc l i p dat tai N h i may Boe ong D i u
khi t d t h i n g 8/2009 den nay la day chuyin cdng n g h i bpc
chong an mdn t i l n t i l n nhat hien nay v i dang dupc sd
dung rdng rai t r l n t h i gidi Qua gan 3 nam khai thac, d i y
chuyen cdng n g h | bpc chdng an mdn 3LPE/PP cda N h i
may da thUc h i l n thanh cong nhieu dU an vdi chat lUpng
dat chuin qudc t l (Bang 2)
2 Tren thye te, mdt sd d y i n y l u c i u i p dung cdng
nghe bpc 5 Idp PP (5LPP) de sin p h i m chiu dUPe dieu k i l n
mdi trudng d i e biet khic nghilt nhU: ehiu dupc nhiet dp
eao khi van h i n h (tdi 150°C), chiu dUPc i p lye ben n g o i i
cao {tuyln dng dupc l i p d i t d khu vUc nude s i u hoic r i t
siu) D i y l i loai bpc each n h i l t ed edng n g h i r i t phdc
tap v i thi cdng khd khan, ke c i ddi vdi cic n h i m i y bpe
ong t r l n t h i gidi da cd h i n g chuc nam kinh nghiem Tuy
nhien, PVID da quyet djnh de xuat nhilm vy nghiln cdu,
thiet ke v i l i p dat d i y ehuyen cdng n g h i mdi bpc dng 5
Idp tai N h i m i y Bpc dng D i u khi n h i m hpp ly hda d i y
chuyin cdng n g h i h i l n cd va bo sung d i y ehuyen cdng
nghe mdi Hien nay, day chuyen edng n g h i bpe dng 5 Idp
da dupe l i p dat h o i n chinh, chay t h d dat k i t q u i tdt v i
sin sang phyc vu cic dU i n bpe 5 Idp
3 Den nay, N h i m i y Bpe ong Dau khi dang v i n h i n h
5 d i y chuyin cdng nghe bpe dng Hai d i y chuyen dupe
lap dat ban dau do Nha thau ehinh - T i p doan Bauhuis
International B.V cua Ha Lan thuc hien, dd l i :
+ Diy chuyen dong bp bpc ehdng an mdn cho cic
dudng ong, sddung phUOng phap boc ba Idp 3LPE/PP k i t
hpp vdi Idp Idt FBE
-h D i y chuyin ddng bd bpc b l tdng gia t i i cho dddng dng, duac sd dung cdng n g h i phun v i n g l i l n tue cd ludi
t h i p gla cudng cho b l tdng
Ngoii ra Ban lanh dao, ddi ngu c i n bd khoa hpc cua Nha m i y ndi n i n g v i PVID ndi ehung da phat huy tinh
t y chu, sing tao, dam nghT d i m l i m va q u y l t tam cao (t^ dng dung cdng n g h i mdi vdo sin xuat Kit q u i la da thUc hien l i p dat bo sung h o i n chlnh t h i n h cdng 3 diy chuy&i eong nghe mdi, mpt trong nhdng sd dd l i diy ehuyin edng nghe mdi bpc dng 5 Idp (5LPP} Hat d i y chuyin cdng
n g h i mdi cdn lai l i : + D i y chuyen cdng nghe bpe cieh nhilt bing vit
l i l u PU foam [3]
+ D i y chuyin cdng n g h i bpc bends (bpc dng cong)
D i y l i cdng n g h i r i t phdc tap, nhung b i n g nd lucquy^t
t i m PVID da l i p d i t t h i n h cong d i y chuyin cdng nghe
n i y v i thuc hien t h i n h cdng n h i l u d u i n bpe bends.Trong eac sd b i o t i l p theo, nhdm t i e g i i s i gidi thieu chi t i l t cu the v l d i y chuyin cdng nghe bpc bends va diy chuyin cdng n g h i bpc b l tdng gia t i i tren Tap chi D i u khi
T i i lieu tham k h i o
1 Khdi cdng xdy dung Nha may Boc dng Phu My http://
www.pvid.com.vn
2 DU dn ddu tu xdy dimg Nhd mdy Boc dng Dau khi
http://www.pvid.com.vn
3 PVID dng dung cdng nghe mdi boc dng cdch nhift PU
FOAt^ cho cdc du dn dUdng ong dan ddu trin thim li/c dia Viet Nam T^p ehi D i u khf 2012; 2: p 59 - 65