气相中的稳态分子扩散 (10).pdf

《气相中的稳态分子扩散 (10).pdf》由会员分享，可在线阅读，更多相关《气相中的稳态分子扩散 (10).pdf（11页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、Mechanism of centrifugal pump Principles of Chemical Engineering-CDUTOverview of centrifugal pump The classification of the fluid conveyorfanblowerCompressorvacuum pumpBased on the state of the conveying fluidtransport of liqudtransport of gaspumpPrinciples of Chemical Engineering-CDUTOverview of ce

2、ntrifugal pump The classification of the fluid conveyorBased on the working principlePower type(impeller type)Volume type(positive displacement type)Fluid action typePrinciples of Chemical Engineering-CDUTMechanism of centrifugal pump impellerpump shellpump shaftbottom valvesuction pipesdischarge pi

3、pes1-impeller；2-pump shell，3-pump shaft；4-suction pipe；5-bottom valve；6-extrusion pipediagram of centrifugal pumpCentrifugal pumps account for 80%-90%of pumps for chemical use in the process of chemical productionMechanism of centrifugal pumpPrinciples of Chemical Engineering-CDUTMechanism of centri

4、fugal pump 1.The operation principle of centrifugal pumpBecause there is air in the pump,the density of air is far less than that of liquid,and the centrifugal force generated by the rotation of impeller is small,so the low pressure formed in the center of impeller is not enough to suck the liquid i

5、n the tank into the pump.At this time,although the centrifugal pump is started,the liquid can not be delivered.This phenomenon is called air binding phenomenon.It shows that the centrifugal pump has no self-priming capacityfilled with liquid（vacuum priming）discharge fluid:Exit tangent directionimbib

6、ition：the center of impellerpump shellimpellerdischarge outletpump shaftPrinciples of Chemical Engineering-CDUT2.Main parts of centrifugal pumpImpellerthe key components of centrifugal pumpFunction：To transfer the mechanical energy of the prime mover to the liquid,so that the static pressure energy

7、and kinetic energy of the liquid passing through the centrifugal pump are improved.Impeller consists of 6-8 backward bend bladesBased on the mechanical structureopened impellerThe open impeller has only blades and hubsand no cover plates on both sides.It has theadvantages of simple structure and con

8、venientcleaning.Mechanism of centrifugal pump pump caseimpellerPrinciples of Chemical Engineering-CDUT2.Main parts of centrifugal pumpImpellerthe key components of centrifugal pumpFunction：To transfer the mechanical energy of the prime mover to the liquid,so that the static pressure energy and kinet

9、ic energy of the liquid passing through the centrifugal pump are improved.Impeller consists of 6-8 backward bend bladesBased on the mechanical structureHalf opensemi-enclosed impeller,it has no front shroud,but aback shroud.Mechanism of centrifugal pumppump caseimpellerPrinciples of Chemical Enginee

10、ring-CDUT2.Main parts of centrifugal pumpImpellerthe key components of centrifugal pumpopenhalf closedIt is suitable for conveying suspension containing solid particles,but the efficiency of the pump is low.Mechanism of centrifugal pumpFunction：To transfer the mechanical energy of the prime mover to

11、 the liquid,so that the static pressure energy and kinetic energy of the liquid passing through the centrifugal pump are improved.Impeller consists of 6-8 backward bend bladesBased on the mechanical structurepump caseimpellerPrinciples of Chemical Engineering-CDUT2.Main parts of centrifugal pumpImpe

12、llerthe key components of centrifugal pumpShrouded ImpellerThere are front and rear covers on both sides,and the flowchannel is closedsuitable for delivering high head and clean liquidMechanism of centrifugal pumpFunction：To transfer the mechanical energy of the prime mover to the liquid,so that the

13、 static pressure energy and kinetic energy of the liquid passing through the centrifugal pump are improved.Impeller consists of 6-8 backward bend bladesBased on the mechanical structurepump caseimpellerPrinciples of Chemical Engineering-CDUT2.Main parts of centrifugal pumpBased on the imbibition met

14、hodssingle-suction impeller：Fluid is drawn in from one side of the impellerdouble-suction impeller：It is symmetrical on both sides,and the liquid is drawn in from both sides of the impeller.It has a larger imbibition capacity and can basically eliminate the axial thrustsingle-suctiondouble-suctionMe

15、chanism of centrifugal pumpPrinciples of Chemical Engineering-CDUTPump shaftTo collect liquid，and act as a channel for the outflow of liquid；It can converts some of the kinetic energy of the liquid into static pressure energy.The shaft sealing device Avoid leakage of high-pressure liquid in the pump

16、 along the gap;；To prevent outside air from entering the pump in the opposite direction.packing seal：It is mainly composed of stuffing box shell,soft packingand packing glandmechanical seal：Also known as face seal,it is mainly composed of a movingring installed on the shaft and a static ring fixed on the pump body.classification：Mechanism of centrifugal pump