Method of separating a lighter dispersed fluid from a denser liquid in a hydrocyclone having flow-modifying means

Claim 1

A method of separating a fluid mixture of a dispersed phase of a lighter component in a continuous phase of a denser liquid component, comprising feeding said mixture to a hydrocyclone comprising opposite first and second ends, between which a hydrocyclone axis extends, the hydrocyclone having a cross-sectional area decreasing overall from said first end to said second end; inlet means adjacent to said first end for introducing the mixture into said hydrocyclone; and first and second outlet means for discharging respectively comparatively less and comparatively more dense components separated from said mixture, said first outlet means being located substantially on said hydrocyclone axis; and said second outlet means being adjacent to said second end; the cyclone further having a nominal hydrocyclone diameter d 2 defined by: ##EQU9## where V represents an effective internal volume of the hydrocyclone not including inlet and outlet ducts; said inlet means comprising a number of inlets in the region of said first end said number being an integer n with a value of at least 1, wherein at least a part of said mixture is fed through one of said inlets designated the P th inlet into said hydrocyclone with a mass flow rate m and a momentum per unit time L p (L p being a vector quantity), <L p being a vector component of L p parallel to a plane normal to the hydrocyclone axis at the P th inlet, r p being the minimum radius from the hydrocyclone axis to a point on a line of direction of said vector component <L p , r p being parallel to the plane normal to said hydrocyclone axis at the p th inlet and r p being perpendicular to a line of direction of said vector component <L p , d i being an effective diameter of the said first end being defined as: ##EQU10## and A i being an effective inlet area as defined by: ##EQU11## where A p is a total cross-sectional area at the P th inlet at entry to the hydrocyclone in a plane parallel to said hydrocyclone axis at inlet p and normal to the vector component <L p ; the following criteria exist: A. 3<V r 28, where ##EQU12## B. the hydrocyclone measured along said hydrocyclone axis from said first end to said second end is at least 10d 2 long; C. said hydrocyclone includes a section situated between said first and second end, of at least 8d 2 long when measured along said hydrocyclone axis where: 15'<α<20 α being an average half angle of convergence of a side wall of said hydrocyclone; and, D. said first outlet means having a minimum effective cross-section diameter d o where ##EQU13## and there being provided adjacent to said second end, means to convert at least some rotational motion of said liquid about said hydrocyclone axis to a motion which is substantially linear while imposing minimal viscous drag forces on said liquid while said liquid has a substantially rotational velocity.

Claim 2

A method of separating a fluid mixture of a dispersed phase of a lighter component in a continuous phase of a denser liquid component, comprising feeding said mixture to a hydrocyclone comprising opposite first and second ends, between which a hydrocyclone axis extends, the hydrocyclone having a cross-sectional area decreasing overall from said first end to said second end; inlet means adjacent to said first end for introducing the mixture into said hydrocyclone; and first and second outlet means for discharging respectively comparatively less and comparatively more dense components separated from said mixture, said first outlet means being located substantially on said hydrocyclone axis; and said second outlet means being adjacent to said second end; the cyclone further having a nominal hydrocyclone diameter d 2 defined by: ##EQU9## where V represents an effective internal volume of the hydrocyclone not including inlet and outlet ducts; said inlet means comprising a number of inlets in the region of said first end said number being an integer n with a value of at least 1, wherein at least a part of said mixture is fed through one of said inlets designated the P th inlet into said hydrocyclone with a mass flow rate m and a momentum per unit time L p (L p being a vector quantity), <L p being a vector component of L p parallel to a plane normal to the hydrocyclone axis at the P th inlet, r p being the minimum radius from the hydrocyclone axis to a point on a line of direction of said vector component <L p , r p being parallel to the plane normal to said hydrocyclone axis at the p th inlet and r p being perpendicular to a line of direction of said vector component <L p , d i being an effective diameter of the said first end being defined as: ##EQU10## and A i being an effective inlet area as defined by: ##EQU11## where A p is a total cross-sectional area at the P th inlet at entry to the hydrocyclone in a plane parallel to said hydrocyclone axis at inlet p and normal to the vector component <L p ; the following criteria exist: A. 3<V r 28, where ##EQU12## B. the hydrocyclone measured along said hydrocyclone axis from said first end to said second end is at least 10d 2 long; C. said hydrocyclone includes a section situated between said first and second end, of at least 8d 2 long when measured along said hydrocyclone axis where: 15'<α<20 α being an average half angle of convergence of a side wall of said hydrocyclone; and, D. said first outlet means having a minimum effective cross-section diameter d o where ##EQU13## and there being provided adjacent to said second end, means to convert at least some rotational motion of said liquid about said hydrocyclone axis to a motion which is substantially linear while imposing minimal viscous drag forces on said liquid while said liquid has a substantially rotational velocity.

Claim 16

A method of separating a fluid mixture of a dispersed phase of a lighter component in a continuous phase of a denser liquid component, comprising feeding, said mixture to a hydrocyclone comprising opposite first and second ends, between which a hydrocyclone axis extends, the hydrocyclone having a cross-sectional area decreasing overall from said first end to said second end; inlet means adjacent to said first end for introducing the mixture into said hydrocyclone; and first and second outlet means respectively adjacent to said first and second ends for the discharge respectively of comparatively less and more dense components separated from said mixture, said first outlet means being located substantially on said hydrocyclone axis; the cyclone further having a nominal hydrocyclone diameter d 2 defined by: ##EQU14## where V represents an effective internal volume of the hydrocyclone not including inlet and outlet ducts; said inlet means comprising a number of inlets in the region of said first end said number being integer n with a value equal to at least 1, wherein at least a part of said mixture is fed through one of said inlets designated the P th inlet into said hydrocyclone with a mass flow rate m and a momentum per unit time L p (L p being a vector quantity), <L p being a vector component of L p parallel to a plane normal to the hydrocyclone axis at the P th inlet, r p being a minimum radius from the hydrocyclone axis to a point on a line of direction of said vector component <L p , p being parallel to the plane normal to said hydrocyclone axis at the P th inlet and r p being perpendicular to the line of direction of said vector component <L p , d i being an effective diameter of the said first end being defined as: ##EQU15## and A i being an effective inlet area as defined by: ##EQU16## where A p is a total cross-sectional area at the p th inlet at entry to the hydrocyclone in a plane parallel to said hydrocyclone axis at inlet p and normal to the vector component <L p ; the following criteria exist: A. 3<V r <28, where ##EQU17## B. the hydrocyclone measured along said hydrocyclone axis from said first end to said second end is at least 10d 2 long; C. Said hydrocyclone includes a section situated between said first and second end, of at least 8d 2 long when measured along said hydrocyclone axis where: 1'<α< ° α being the average half angle of convergence of a side wall of said hydrocyclone; and, D. said first outlet means having a minimum effective cross-sectional diameter d o where ##EQU18## there being provided adjacent to said second end means to convert at least some rotational motion of said liquid about said hydrocyclone axis to a motion which is substantially linear while imposing minimal viscous drag forces on said liquid while said liquid has a substantially rotational velocity; and wherein said hydrocyclone includes flow-modifying means providing part way along said hydrocyclone axis from said second end towards said first end an obstruction to increase at least one of the pressure and flowrate of comparatively less dense component out of said first outlet means; and wherein the ratio of the minimum effective area of said hydrocyclone cross-section (A 1 ) of that part of said hydrocyclone between said first end and said obstruction to the effective cross-sectional area (A 2 ) of said obstruction is greater than 2.

Claim 17

A method of separating a fluid mixture of a dispersed phase of a lighter component in a continuous phase of a denser liquid component, comprising feeding, said mixture to a hydrocyclone comprising opposite first and second ends, between which a hydrocyclone axis extends, the hydrocyclone having a cross-sectional area decreasing overall from said first end to said second end; inlet means adjacent to said first end for introducing the mixture into said hydrocyclone; and first and second outlet means respectively adjacent to said first and second ends for the discharge respectively of comparatively less and more dense components separated from said mixture, said first outlet means being located substantially on said hydrocyclone axis; the cyclone further having a nominal hydrocyclone diameter d 2 defined by: ##EQU14## where V represents an effective internal volume of the hydrocyclone not including inlet and outlet ducts; said inlet means comprising a number of inlets in the region of said first end said number being integer n with a value equal to at least 1, wherein at least a part of said mixture is fed through one of said inlets designated the P th inlet into said hydrocyclone with a mass flow rate m and a momentum per unit time L p (L p being a vector quantity), <L p being a vector component of L p parallel to a plane normal to the hydrocyclone axis at the P th inlet, r p being a minimum radius from the hydrocyclone axis to a point on a line of direction of said vector component <L p , p being parallel to the plane normal to said hydrocyclone axis at the P th inlet and r p being perpendicular to the line of direction of said vector component <L p , d i being an effective diameter of the said first end being defined as: ##EQU15## and A i being an effective inlet area as defined by: ##EQU16## where A p is a total cross-sectional area at the p th inlet at entry to the hydrocyclone in a plane parallel to said hydrocyclone axis at inlet p and normal to the vector component <L p ; the following criteria exist: A. 3<V r <28, where ##EQU17## B. the hydrocyclone measured along said hydrocyclone axis from said first end to said second end is at least 10d 2 long; C. Said hydrocyclone includes a section situated between said first and second end, of at least 8d 2 long when measured along said hydrocyclone axis where: 1'<α< ° α being the average half angle of convergence of a side wall of said hydrocyclone; and, D. said first outlet means having a minimum effective cross-sectional diameter d o where ##EQU18## there being provided adjacent to said second end means to convert at least some rotational motion of said liquid about said hydrocyclone axis to a motion which is substantially linear while imposing minimal viscous drag forces on said liquid while said liquid has a substantially rotational velocity; and wherein said hydrocyclone includes flow-modifying means providing part way along said hydrocyclone axis from said second end towards said first end an obstruction to increase at least one of the pressure and flowrate of comparatively less dense component out of said first outlet means; and wherein the ratio of the minimum effective area of said hydrocyclone cross-section (A 1 ) of that part of said hydrocyclone between said first end and said obstruction to the effective cross-sectional area (A 2 ) of said obstruction is greater than 2.