I. Hanh trinh xu6ng:
1.cau t{lO Van:
6.2.4. Tinh va chon van ti~tIU'u.
Ky hieu :
*Nguyen Ij hoat il~ng:
Chat long lam viec nr born d:ln buong (a) va bi dclyv6 thung chua qua
buong (b).Trong 16 thong co 16 tiSt hru nho do buong (a) luon luon thong voi buong (c).Lo xo co tac dung bi van dS van, irng lire cua 10 xo cothSdieu chinh bang vit. Khi van bi chua mo ra nrc la ap suAt chat long chua thang duoc 10
xo.Khi do buong (a) thong voi buong (c), (d) va (e) nhung khong thong voi buong (b). Nhir v~y,diu trong cac buong atrang thai tinh.
Vi vay ap suat trong cac buong (a),(c), (d), (e) tang d(>tngot, ap hrc ch~t
long qua 16 (9) thang duoc 10xo (5) va chat long nr buong (c) v6 thung chua nho
16 tiSt hru (8) gay nen t6n th~t tao S1,[chenh lech ap su~t giira cac buong
d,e,c.Nhu vay, trang thai can bang tac dung len pistong (2) mat di va duoi tac
dung diu ep co ap suat 11,[ccao abuong (d) va (cj.Pistong (2) duoc nang len cho
dSn khi ap luc diu va 10xo (3)duqc xac l~p,pistong (2) dung lai,do do lam cho
buong (a) thong vci buong (b),Ch~t long chay v6 thung chua va giam ap cho M thong.
Trong thuc tS nguoi ta di6u chinh van (A) nrc la luon luon co ch~t long
thoat tir Mthong v6 chira.Luc do van an toan co tinh nang nhu mot van tran dS
thoat hru luong thua cua bam v6 thung clnra.Khi van bi(4) lam viec thi hieu ap
~P =P, - P3 .Phuthuoc van tiSthru (8) va hru luong qua 16tiSthru (Pj :ap suat
buong (a); P3 .ap suat buong (c)) ap su~tnay cling chinh xac neu hru hrong qua
bi cang nho.
* U'u di~m :Loai van nay lam viec r~t em, khong co chan dong, ap su~t co thSdieu chinh trong pham virAtrong.
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SVTH: PHAUMDUY NGHEA
2. Nguyen If lam viec :
Van ti~t hru di~u chinh quanh true, di~u chinh luu hrong bang each xoay ch6t ti~t hru (1) quanh true cua no voi goc h'r 0 - 180 0 . Ranh ti~t hru codang hinh tam giac quay quanh m~t tru cua ch6t (1) diu duoc dftnttr ngoai vao, qua ranh ti~t luu (2) va (3) ben trong ti~t hru d€ ra ngoai.
Theo cong thirc Torielli hru luong chay qua mot khe ho co ti~t dien Axva hieu ap I1p= PI- P2 thi: