- Bien dBi trl so" t6c dQ ti rg ii tli b6ng hdt dgn gid tri khi vAo bdnh c6ng tic dat tdn th$t nh6 nnht.
d) Dat phin huhg kinh vho dia chinh c6a b lh cbng t6c (hi& 111.1
Bum chim AGREX 285/4 dZ sir dung h8n hqp bien phip can bang b vh c nen dat hieu quii caọ
bi&n phAp kh5c nhau (hinh
a ) b )
Hinh 111.16. So đ cuc bi{n phdp Zum gidm Zgc h u i i g trEm
4.1. Giiii thieu chung
Sq phPt tridn cGa Iinh vuc ky t h u ~ t IBm kin g i n li&n vdi su phdt trign cha nginh ch6i tao miiy cfing n h ~ n h h g tign b6 cha chc ngAnh kg thugt khac ( q u a su,
vii t ~ . . . ) . ~ b i v6i miy b m chim - mot sin phdm thuQc loai cbng ngh@ cao, thi vgn d$ Ihm kin c6 9 nghia r$t quan trong. Mac du c y n thigt bi vbng lhm kin c a khi
chigm t3 trong kh6ng l h so vdi c i miy b m nhmg chgt luwg lam viec cha c i td
bam lai phu thuec r$t nhi&u vBo chgt 1umg c6a vbng 1hm kin cu khị
Thi&t b/ Ilm kin c3a cac t ~ c quay c6 thg phen thhnh ccc loai chinh: vbng cao su, gioing cao su, t$m chan kim loai, vbng lim kin dqng IUC vh vbng Wm kin ki$u
d$u cm. J
C i c vbng cao su, gioang cao su v i tCim chan kim loai ~ U U C sir dung chii ygu d6i vdi c8c k&t cgu c 6 s~ rb ri nhb v B 4p sugt h 6 n g l h . Vbng lim kin deng luc vh vbng lam kin'kidu d l u mfit duqc sir dung rQng riii đi vdi c l c miy m6c c6 sq rb ri
nh6 vB ip sufit l h . Ddi vdi c i c k6it cgu may born cKm h u h g dung nhieu vbng Ihm kin ki&u d$u mdt.
Vbng lhm kin ki&u dlu mut c6 c i c uu didm sau: a) Khi lim viec binh t h ~ h g khbng phhi b i o d ~ k g b) Lhm viec vdi su rb ri nhb
c) C6 tudi tho dhi ngu sii dung d h g k j thugt
d) C6 thd IBrn vi&c v6i di&u ki&n Pp su9t cao (P = lQ-5mm thuy n g b dEn 4 5 0 ~ G / c m ~ ) , nhiet do T = - 200 i + 450°C, van t8c trugt trong dbi ma sit V = 0
+lo0 m/s; ap dung tBt cho cac m6i t m h g chgt Ibng nv6c c6 phu sa, biin, cit vB cic v!t ran khiic.
Loai vbng lhm kin c a khi (VLKCK) y&u c$u cbng sudt nh6 hm nhigu so vdi vbng cao su (VCS) (AN,,,, = 0,l - O,5 ANN,,,) v i c6 th6 sir dung cho t q c c6 kich
thudc l h D = 1500 rnm. Tuy nhien, nhuuc diem cSa vbng lam kin ca khi 1I phirc tap, c6 tinh dgc ch6ng cho timg k6t cgu cu th6, gi8 thlnh cao, thay t h t phirc tap do phii thio may khi vbng lam kin ca khi bi hbng.
4.2. NguyCn 1y lhm viec va phan loai vbng lam kin ca khi
4.2.1. Nguykn ly him vi+c ccu vvdng him kin cg khi kigu &'u mut
Vbng lirn kin kieu d8u mut c6 nhi&u dang khlc nhau nhung v& k&t cgu c6 chung m6t s o đ nhu hinh IV. 1
-: Hhlr IV.1. Sop d6 kt?? cdu vdng lam kin ki& dau mht
Truc quay 1 c6 lien k6t ch3t v& vbng Jim kin ca khi the0 nguy&n 19 dLn h6i 4 vh vbng chan 2. B& mat dLu mlit cha vbng lam kin ca khi 4 ti&p xdc v6i vbng ch?n 2 vh 6p chat vho vbng kim loai 3 n6i v6.i v8 mhy 5. Vbng kim Ioai 2 vh 3 tao thlnh cap ma slt ph8ng. Khe hb giila chdng xhc djnh trj sd rb ri cha c h 9 16ng nhm trong
vb mhy v6i Ap sugt P. Chi ti61 4 chinh 1 l chi ti& dhn h6i v h ~ U U C gqi l i vbng lhm kin c a khi cdn dHm b60 dQ ch?t v i kp d$u cb d m len cAc vbng kirn loai 2 vh 3 ngay c i khi co su rung dong l h , t y c quay v i su mbn cha cGp ma s5t. .
4.2.2. Phdn loui vting ldm kin ca khi
C6 thd phPn loai vbng l l m kin co khi dga vAo dBc didm kgt c L ciia chi ti& dPn h8i (hinh lV.2). C i c dac dikm d6 xhc dinh khdng n h h g qua hinh thtic Mn
ngoli m i cii bhn chgt dong lgc ciia vbng 1Brn kin cd khị
Vbng Iim kin ca khi 1h c i c vbng Ib so kEt hup vdi c i c vbng cao su, chc siphon hay c,ic ming cao sụ
Vbng l i m kin c a khi duuc chia thsnh c i c ki&u vbng Ism kin v6i cac chi ti& d i n hdi quay v i c5c chi tie3 d i n hbi tinh dugc trinh bly the0 dang sa d6 ir hinh
IV.2.
Vbng l i m kin ccr khi vdi chi ti& d i n hdi quay t h u h g lh loai k&t cgu trong c6
co khi vdi chi ti& dan h8i t-31 la loai k&t caIu ngoei duqc lip chat viri p h h phia ngoii v6 maỵ
CAc vbng llam kin c a khi c6 th6 k&t hop vdi cic siphon v i c i c vbng lhrn kin hay cic gioang cao su vdi 16 sọ Chc tgrn mPng cao su chi sir dung dBi vdi cic chi
ti& dhn hdi tlnh vi kic h thudc h u h g tarn I h .
Vbng l l m kin co khi c6 th6 c6 k&t cgu d m hơc kkp. Loai k&t cgu kkp thulmg sir dung cho cbc van ch+n vdi chgt 16ng c6 i p su9't l h h m Ap suift chgt lbng b phia tm6c gioiing l i Ap = 0,5 - 2 ~Glcrn'.
< I V6i chi ti& dhn hdi quay
Kidu phfa I I Kiku phia
trong I 1 ngoai
V6i k& cgu
siphon
V6.i chi ti& din hBi tinh
V d vbng kjn-~ lo@ hay vbng cao su ki&u k&p & -
~ i 6 u phia I I Kieu phia I
kiku dun
=&. - &. -
-
V6i kei cslu v6i k&t cslu v6.1 lo@ hay vbng
1 siphon 1 rnhg ' 1 r m a K&t c$u kiku don @ ++--- 2ii- - - -- - -
Xem xtt cAc yQ t6 Bnh h u h g den t h g loai vbng lam kin c a khi c6 thd tdng
h q the0 4 nh6m sau:
- Nh6m I: Chc vbng lam kin cho chc m6i t h g binh t h u h g (nudc, d h ma hay cic s i n phdm dAu).
- Nhom 11: Cic vbng Ism kin đi v6i c i c m6i t n h g axit, kiem, baza, dung djch mudi, hoi, khị. .
- Nhdm 111: CBc vbng lhm kin dBi vbi c i c m6i t n r h g chgt 16ng c6 c h h cic hdn
hqp cimg nhu bun, cit, cBc bom gigng sau, barn dung djch gigỵ
- Nhom IV: Cic vbng lam kin kidu d l c bi@t
C i c thOnp s6 ky thubt quan trqng c h luu 9 khi lua chon chc loai kU csu cha
vdng llm kin ca khi 11 dp sugt chgt 16ng phia tnrdc vbng 1Brn kin (p) vh van t6c tmqt (V) trong cgp ma sdt (thong qua d u h g kinh vh vqn t6c quay c6a tyc). Tich
cha hp sugt (p) vb van t6c (V) sE c6 tri s6 cira th0ng s6 tho ba (pV) r$t quan trqng
đi vdi c i c vbng 11m kin ca khị Chc th6ng s6 kjj thugt c6a 4 nh6m k6t c$u vbng lhm kin c a khi duuc t r i h biy tren bing JY.1.
Bdng 1V.Ị Cdc thBng s$kE thu(it cda vbng Idm kin ca khi
4.3. C i c ke"t cgu ciia vbng lam kin cd khi
TT
1
2
3
4
4.3. I . Vbng him kin cu khi nhdm I , Ỉ cho m6i a t h g binh th rchg (nmic vct sdn phdh đu)
Loai vbng lhm kin ca khi nh6m I, II duqc diing rQng r5i cho ciic mAy bom
chim kidu ly tam vh dbng chko, cAc miiy bom thd tich kidu binh rang, ttyc vit. Nhom I LI 111 IV P ( ~ G l c m ~ ) I 1 < 10 1 50 > 50
Xac dinh thong so
. Nh6 nhgt Nh6 nhgt Trung binh Cao Cao nhát v (m/s) I I0 I I0 1 20 > 20 Pv ( ~ G l c m ' x mis) I 1 0 1 50 1 500 > 500
Chc vbng lhm kin loai nhy duuc sin xugt v6i cc8c siphon cao su, chc t$m mhng
cao su hay vbng kim loai vdi chc vbng lb so &n h8ị Chc chi ti& dhn h8i c6 . ~ & la
quay ( t ~ c ) hay tinh (vb may) (hinh IV.3). ~p s u n lam viec p = 0 - 4 ~G/crn', nhi&t
d? T = - 10 t + l O o O ~ , s6 vbng quay cba tryc n 5 3000 v/ph.
Hinh W.3. V d n g l a m kin v& siphon Hinh IV.4. V6ng lam kin v& t h
can su g u q mdng cao su