Electrostatic dust separator

Claim 2

An electrostatic dust separator comprising: a Venturi unit having an inlet and an outlet for a dust-laden gas; a high-voltage ionizing electrode disposed axially of said Venturi and terminating substantially at the outlet thereof, said ionizing electrode being in the form of a rod having thin longitudinally extending radial fins to ionize dust particles in the gas within said unit, and said ionizing electrode having a predetermined polarity; a high-voltage polarizing electrode forming an extension of said ionizing electrode beyond the outlet of said Venturi unit, said electrode being in the form of a smooth rod, said polarizing electrode having the same polarity as said ionizing electrode; spraying means to produce around said polarizing electrode a spray of particles of an auxiliary substance; and means to collect said sprayed particles together with the dust particles which they have attracted and retained.

Claim 3

In a dust separator as claimed in claim 1, means to recycle into the inlet of said Venturi unit a portion of the gas issuing from the outlet thereof.

Claim 4

In a dust separator as claimed in claim 1: an outer casing axially enclosing said Venturi unit while leaving an annular gas-recycling passage around same; an axial injector nozzle in said outer casing in front of the inlet of said Venturi unit to receive the gas to be treated and to inject same into said inlet together with a portion of the gas issuing from the outlet of said Venturi unit upstream of the spraying means, said portion thus being recycled through said passage.

Claim 5

In a dust separator as claimed in claim 3, a butterfly valve disposed within said injector nozzle, the diameter of said valve being such that at its position transverse to said injector nozzle it leaves an annular gas passage through said injector nozzle.

Claim 6

In a dust separator as claimed in claim 1, an intermediate casing axially enclosing said Venturi unit while being spaced therefrom, said intermediate casing having a first and a second end respectively joined to the inlet and to the outlet of said Venturi unit so as to determine therewith a closed annular space, and said Venturi unit and said intermediate casing being made of an electrical conducting material; means within said closed annular space to form a radially directed electrical connection between said Venturi unit and said intermediate casing; an electrically conducting outer casing enclosing said intermediate casing while leaving an annular gas passage between itself and said intermediate casing; means to form a radially directed connection between said intermediate casing and said outer casing; means to recycle into the inlet of said Venturi unit through said annular gas passage a portion of the gas issuing from the outlet of said Venturi unit; and means to electrically connect said intermediate cas-ing with said outer casing.

Claim 7

An electrostatic dust separator comprising: a Venturi unit having an inlet at one end for the dust-laden gas to be treated, and an outlet at the other end through which said gas issues; a high-voltage ionizing electrode axially dIsposed in said Venturi unit to ionize dust particles in the gas flowing therethrough; spraying means adjacent the outlet to produce in the gas issuing from said Venturi unit a spray of particles of an auxiliary substance; electrifying means adjacent the outlet to electrify said sprayed particles with such a polarity that they attract and retain ionized dust particles in the gas issuing from said Venturi unit; and means adjacent said outlet to collect said sprayed particles together with the dust particles which they have retained; an auxiliary Venturi unit disposed downstream of the first named unit to receive the gas issuing from the outlet of said first-named Venturi unit, said auxiliary Venturi unit having an inlet portion disposed adjacent the outlet of the first named Venturi unit, and having a neck portion and an outlet portion with said spraying means and said electrifying means being so disposed within said auxiliary Venturi unit that the spray of particles of said auxiliary substance is produced in the vicinity of the neck portion of said auxiliary Venturi unit in order that said particles of said auxiliary substance may act on the dust particles in a zone wherein the gas which contains said dust particles flows with a high velocity.

Claim 8

An electrostatic dust separator comprising: a Venturi unit having an inlet at one end for the dust-laden gas to be treated, and an outlet at the other end through which said gas issues; a high-voltage ionizing electrode axially dIsposed in said Venturi unit to ionize dust particles in the gas flowing therethrough; spraying means adjacent the outlet to produce in the gas issuing from said Venturi unit a spray of particles of an auxiliary substance; electrifying means adjacent the outlet to electrify said sprayed particles with such a polarity that they attract and retain ionized dust particles in the gas issuing from said Venturi unit; and means adjacent said outlet to collect said sprayed particles together with the dust particles which they have retained; an auxiliary Venturi unit disposed downstream of the first named unit to receive the gas issuing from the outlet of said first-named Venturi unit, said auxiliary Venturi unit having an inlet portion disposed adjacent the outlet of the first named Venturi unit, and having a neck portion and an outlet portion with said spraying means and said electrifying means being so disposed within said auxiliary Venturi unit that the spray of particles of said auxiliary substance is produced in the vicinity of the neck portion of said auxiliary Venturi unit in order that said particles of said auxiliary substance may act on the dust particles in a zone wherein the gas which contains said dust particles flows with a high velocity.

Claim 9

An electrostatic dust separator comprising: an elongated outer casing having a first end and a second end; an injector nozzle disposed in axial alignment with the axis of said outer casing and at the first end of said outer casing to receive the dust-laden gas to be treated; a main Venturi unit axially disposed within said outer casing while leaving an annular gas-recycling passage between said main Venturi unit and said outer casing, said main Venturi unit having an inlet portion, a neck portion and an outlet portion, with said inlet portion disposed in spaced relationship to said injector nozzle, said inlet portion being disposed between said injector nozzle and said second end, said inlet portion being disposed downstream of said injector nozzle to receive the gas issuing therefrom, and at a distance therefrom so as to form therewith a gas-recycling injector device; a high-voltage electrode axially disposed within said main Venturi unit to ionize dust particles in the gas flowing therethrough; insulating means to support said ionizing electrode; an auxiliary Venturi unit axially disposed within said outer casing downstream of said main Venturi unit to receive the gas issuing therefrom and leaving an annular space between said outer casing and said auxiliary Venturi unit, said auxiliary Venturi unit having an inlet portion, a neck portion and an outlet portion, with said inlet portion of said auxiliary Venturi unit being spaced from the outlet portion of said main Venturi unit so as to leave an intermediate annular zone; means to substantially prevent gas flow through said annular space; a high-voltage polarizing electrode extending axially of and adjacent to the inlet portion of said auziliary Venturi unit; insulating means to support said polarizing electrode; an annular spraying nozzle axially disposed in the outlet portion of said auxiliary Venturi unit to produce an annular diverging spray of electrically conducting liquid particles which surrounds said polarizing electrode and passes through said intermediate annular zone so as to collect within said annular space together with the ionized dust particles which they have retained; means to supply an electrically-conducting liquid to said annular nozzle; means to remove collected liquid and dust particles from said annular space; and means for exhausting gas from the second end of said outer casing downstream of the outlet portion of said auxiliary Venturi unit.

Claim 10

An electrostatic dust separator comprising: an elongated outer casing having a first end and a second end; an injector nozzle disposed in axial alignment with the axis of said outer casing and at the first end of said outer casing to receive the dust-laden gas to be treated; a main Venturi unit axially disposed within said outer casing while leaving an annular gas-recycling passage between said main Venturi unit and said outer casing, said main Venturi unit having an inlet portion, a neck portion and an outlet portion, with said inlet portion disposed in spaced relationship to said injector nozzle, said inlet portion being disposed between said injector nozzle and said second end, said inlet portion being disposed downstream of said injector nozzle to receive the gas issuing therefrom, and at a distance therefrom so as to form therewith a gas-recycling injector device; a high-voltage electrode axially disposed within said main Venturi unit to ionize dust particles in the gas flowing therethrough; insulating means to support said ionizing electrode; an auxiliary Venturi unit axially disposed within said outer casing downstream of said main Venturi unit to receive the gas issuing therefrom and leaving an annular space between said outer casing and said auxiliary Venturi unit, said auxiliary Venturi unit having an inlet portion, a neck portion and an outlet portion, with said inlet portion of said auxiliary Venturi unit being spaced from the outlet portion of said main Venturi unit so as to leave an intermediate annular zone; means to substantially prevent gas flow through said annular space; a high-voltage polarizing electrode extending axially of and adjacent to the inlet portion of said auziliary Venturi unit; insulating means to support said polarizing electrode; an annular spraying nozzle axially disposed in the outlet portion of said auxiliary Venturi unit to produce an annular diverging spray of electrically conducting liquid particles which surrounds said polarizing electrode and passes through said intermediate annular zone so as to collect within said annular space together with the ionized dust particles which they have retained; means to supply an electrically-conducting liquid to said annular nozzle; means to remove collected liquid and dust particles from said annular space; and means for exhausting gas from the second end of said outer casing downstream of the outlet portion of said auxiliary Venturi unit.