武汉理工大学：《船舶辅机》课程教学资源（PPT课件，英文版）4 Alfa – Laval separator

Alfa- laval separator (

4 Alfa – Laval separator (I)

4. 1 Function The purpose of the operation is either to liberate a liquid from strange particles, or to separate two intermixed liquids

4.1 Function • The purpose of the operation is either to liberate a liquid from strange particles, or to separate two intermixed liquids

4.1 Definitions Throughput This means the quantity of liquid supplied per unit time. The throughput is given in cu. m/h or Reception ability This means the largest liquid quantity that the bowl can treat per unit time, expressed in cum/h or lh

4.1 Definitions • Throughput – This means the quantity of liquid supplied per unit time. The throughput is given in cu. m/h or l/h. • Reception ability – This means the largest liquid quantity that the bowl can treat per unit time, expressed in cu.m/h or l/h

4.1 Definitions Purification A liquid-liquid separation in which the machine is used for separating two intermixed liquids, which are insoluble in each other and have different specific gravities. Solids with specific gravities higher than those of the liquids can be separated off at the same time

4.1 Definitions • Purification – A liquid − liquid separation in which the machine is used for separating two intermixed liquids, which are insoluble in each other and have different specific gravities. Solids with specific gravities higher than those of the liquids can be separated off at the same time

4.1 Definitions Clarification a liquid -sludge separation in which the machine is used to separate particles, normally solid ones, from a liquid having a lower specific gravity than that of the particles

4.1 Definitions • Clarification – A liquid - sludge separation in which the machine is used to separate particles, normally solid ones, from a liquid having a lower specific gravity than that of the particles

4.1 Definitions 。 Concentration A liquid-liquid separation in which the machine is used for separating two intermixed liquids, which are insoluble in each other and have different specific gravities, the heavier liquid constituting the major part of the mixture Solids with specific gravities higher than those of the liquids can be separated off at the same time

4.1 Definitions • Concentration – A liquid − liquid separation in which the machine is used for separating two intermixed liquids, which are insoluble in each other and have different specific gravities, the heavier liquid constituting the major part of the mixture. – Solids with specific gravities higher than those of the liquids can be separated off at the same time

4.1 Definitions Solids eiection Emptying of the bowl during operation by uncovering and closing slots in the bowl wall Total eiection Total emptying of the bowl with the feed (as a rule) turned off

4.1 Definitions • Solids ejection – Emptying of the bowl during operation by uncovering and closing slots in the bowl wall. • Total ejection – Total emptying of the bowl with the feed (as a rule) turned off

4.1 Definitions Partial ejection Total or partial emptying of the solids space in the bowl but without emptying the rest of the bowl The feed need not be interrupted Combined programme A combination of total and partial ejections in succession

4.1 Definitions • Partial ejection – Total or partial emptying of the solids space in the bowl but without emptying the rest of the bowl. – The feed need not be interrupted. • Combined programme – A combination of total and partial ejections in succession

4.1 Factors influencing the separation Difference in specific gravity The centrifugal force acts on all particles proportionally to their specific gravity This applies to solid Particles as well as to fluid particles The greater the difference in specific gravity, the easier the separation

4.1Factors influencing the separation • Difference in specific gravity – The centrifugal force acts on all particles proportionally to their specific gravity. – This applies to solid Particles as well as to fluid particles. – The greater the difference in specific gravity, the easier the separation

4.1 Factors influencing the separation Size and shape of particles The larger the particle, the quicker the sedimentation The particles to be separated off must not be so small that the mixture is close to colloidal state The smooth and round particle is easier separated off than the irregular one Rough treatment, e.g. in pumps, can split the particles with reduced size and separating speed as a result

4.1 Factors influencing the separation • Size and shape of particles – The larger the particle, the quicker the sedimentation. – The particles to be separated off must not be so small that the mixture is close to colloidal state. – The smooth and round particle is easier separated off than the irregular one. – Rough treatment, e. g. in pumps, can split the particles, with reduced size and separating speed as a result