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Bai giang "ieukhien kh nen "

CHNG 1: C S LY THUYET VE KH NEN.

1.1. S PHAT TRIEN CUA KY THUAT KH NEN ng dung kh nen a co t thi trc Cong Nguyen, tuy nhien s phat trien cua khoa hoc ky thuat thi o khong ong bo, nhat la s ket hp cac kien thc ve c hoc, vat ly, vat lieu ... con thieu, cho nen pham vi ng dung cua kh nen con rat han che. Mai en the ky th 19, cac may moc thiet b s dung nang lng kh nen lan lt c phat minh. Vi s phat trien manh me cua nang lng ien, vai tro s dung nang lng bang kh nen b giam dan. Tuy nhien, viec s dung nang lng bang kh nen van ong mot vai tro cot yeu nhng lnh vc ma khi s dung ien se khong an toan. Kh nen c s dung nhng dung cu nho nhng truyen ong vi van toc ln nh: bua hi, dung cu dap, tan inh nhat la cac dung cu, o ga kep chat trong cac may. Sau chien tranh the gii th hai, viec ng dung nang lng bang kh nen trong ky thuat ieu khien phat trien kha manh me. Nhng dung cu, thiet b, phan t kh nen mi c sang che va ng dung vao nhieu lnh vc khac nhau. S ket hp kh nen vi ien - ien t se quyet nh cho s phat trien cua ky thuat ieu khien trong tng lai. 1.2 KHA NANG NG DUNG CUA KH NEN 1.2.1. Trong lnh vc ieu khien Nhng nam 50 va 60 cua the ky 20 la giai oan ky thuat t ong hoa qua trnh san xuat phat trien manh me. Ky thuat ieu khien bang kh nen c phat trien rong rai va a dang trong nhieu lnh vc khac nhau. Ch rieng Cong Hoa Lien Bang c a co 60 hang chuyen san xuat cac phan t ieu khien bang kh nen. He thong ieu khien bang kh nen c s dung nhng lnh vc ma o hay xay ra nhng vu no nguy hiem nh cac thiet b phun sn, cac loai o ga kep cac chi tiet nha, chat deo hoac cac lnh vc san xuat thiet b ien t, v ieu kien ve sinh moi trng rat tot va an toan cao. Ngoai ra, he thong ieu khien bang kh nen con c s dung trong cac day chuyen ra t ong, trong cac thiet b van chuyen va kiem tra cua thiet b lo hi, thiet b ma ien, ong goi, bao b va trong cong nghiep hoa chat. 1.2.2. Trong cac he thong truyen ong - Cac dung cu, thiet b may va ap: Cac thiet b, may moc trong lnh vc khai thac nh: khai thac a, khai thac than, trong cac cong trnh xay dng nh: xay dng ham mo, ng ham. - Truyen ong quay: Truyen ong ong c quay vi cong suat ln bang nang lng kh nen gia thanh rat cao. Neu so sanh gia thanh tieu thu ien cua mot ong c quay bang nang lngChng 1: C s ly thuyet ve kh nen. 1

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Bai giang "ieukhien kh nen "

kh nen va mot ong c ien co cung cong suat, th gia thanh tieu thu ien cua mot ong c quay bang nang lng kh nen cao hn 10 en 15 lan so vi ong c ien. Nhng ngc lai the tch va trong lng nho hn 30% so vi ong c ien co cung cong suat. Nhng dung cu van vt, may khoan, cong suat khoang 3,5 kW, may mai, cong suat khoang 2,5 kW cung nh nhng may mai vi cong suat nho, nhng vi so vong quay cao khoang 100.000 v/ph th kha nang s dung ong c truyen ong bang kh nen la phu hp. - Truyen ong thang: Van dung truyen ong bang ap suat kh nen cho truyen ong thang trong cac dung cu, o ga kep chi tiet, trong cac thiet b ong goi, trong cac loai may gia cong go, trong cac thiet b lam lanh cung nh trong he thong phanh ham cua oto. - Trong cac he thong o va kiem tra: 1.3. NHNG AC TRNG CUA KH NEN - Ve so lng: co san khap moi ni nen co the s dung vi so lng vo han. - Ve van chuyen: kh nen co the van chuyen de dang trong cac ng ong, vi mot khoang cach nhat nh. Cac ng ong dan ve khong can thiet v kh nen sau khi s dung se c cho thoat ra ngoai moi trng sau khi a thc hien xong cong tac. - Ve lu tr: may nen kh khong nhat thiet phai hoat ong lien tuc. Kh nen co the c lu tr trong cac bnh cha e cung cap khi can thiet. - Ve nhiet o: kh nen t thay oi theo nhiet o. - Ve phong chong chay no: khong mot nguy c nao gay chay bi kh nen, nen khong mat chi ph cho viec phong chong chay. Khong kh nen thng hoat ong vi ap suat khoang 6 bar nen viec phong no khong qua phc tap. - Ve Tnh ve sinh: kh nen c s dung trong cac thiet b eu c loc cac bui ban, tap chat hay nc nen thng sach, khong mot nguy c nao ve mat ve sinh. Tnh chat nay rat quan trong trong cac nganh cong nghiep ac biet nh: thc pham, vai si, lam san va thuoc da. - Ve cau tao thiet b: n gian nen re hn cac thiet b t ong khac. - Ve van toc: kh nen la mot dong chay co lu toc ln cho phep at c toc o cao (van toc lam viec trong cac xy - lanh thng t 1 - 2 m/s). - Ve tnh ieu chnh: van toc va ap lc cua nhng thiet b cong tac bang kh nen c ieu chnh mot cach vo cap. - Ve s qua tai: cac cong cu va cac thiet b c kh nen am nhan tai trong cho en khi chung dng hoan toan cho nen se khong xay ra qua tai. 1.4. U NHC IEM CUA HE THONG TRUYEN ONG BANG KH NEN 1.4.1. u iem:Chng 1: C s ly thuyet ve kh nen. 2

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Bai giang "ieukhien kh nen "

- Do kha nang chu nen (an hoi) ln cua khong kh, cho nen co the trch cha de dang. Nh vay, co kha nang ng dung e thanh lap mot tram trch cha kh nen. - Co kha nang truyen nang lng xa, bi v o nht ong hoc cua kh nen nho va ton that ap suat tren ng ong nho. - ng dan kh nen thai ra khong can thiet. - Chi ph thap e thiet lap mot he thong truyen ong bang kh nen, bi v phan ln trong cac x nghiep he thong ng dan kh nen a co san. - He thong phong nga ap suat gii han c bao am. 1.4.2. Nhc iem: - Lc truyen tai thap. - Khi tai trong trong he thong thay oi th van toc cung thay oi. Bi v kha nang an hoi cua kh nen ln, cho nen khong the thc hien c nhng chuyen ong thang hoac quay eu. - Dong kh nen thoat ra ng dan gay ra tieng on. Hien nay, trong lnh vc ieu khien, ngi ta thng ket hp he thong ieu khien bang kh nen vi ien hoac ien t. Cho nen rat kho xac nh mot cach chnh xac, ro rang u nhc iem cua tng he thong ieu khien. Tuy nhien, co the so sanh mot so kha canh, ac tnh cua truyen ong bang kh nen oi vi truyen ong bang c, bang ien. ST T 1 1.1 1.2 2 2.1 2.2 3 3.1 3.2 Bang 1.1. Pham vi ng dung cua cac he thong ieu khien Trng hp ng dung K -K -C C TL Truyen ong quay vi cong suat > 2kW Truyen ong quay vi cong suat < 2 kW So vong quay > 10.000 v/ph Truyen ong thang, quang ng