US3005594A - Jet mills and the like - Google Patents

Jet mills and the like Download PDF

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Publication number
US3005594A
US3005594A US8954A US895460A US3005594A US 3005594 A US3005594 A US 3005594A US 8954 A US8954 A US 8954A US 895460 A US895460 A US 895460A US 3005594 A US3005594 A US 3005594A
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United States
Prior art keywords
chamber
ground
grinding
grinding chamber
propellant
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US8954A
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English (en)
Inventor
Helmut Vogel
Martin Hartmann
Herbert Spitzner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer Pharma AG
Original Assignee
Schering AG
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Filing date
Publication date
Application filed by Schering AG filed Critical Schering AG
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Publication of US3005594A publication Critical patent/US3005594A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C19/00—Other disintegrating devices or methods
    • B02C19/06—Jet mills
    • B02C19/061—Jet mills of the cylindrical type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C19/00—Other disintegrating devices or methods
    • B02C19/06—Jet mills

Definitions

  • This invention relates to jet mills, and the like.
  • Iet mills for the very fine grinding of solids are already known. They operate in accordance with the principle of the impact mill, the acceleration of the material to be ground being effected not by mechanically moved parts of the apparatus, but rather by the energy of gas or vapor jets which expand into the grinding chamber. They can, for instance, be constructed ina manner that a round or disc-shaped grinding chamber is provided on its top with a tangentially directed injector nozzle for the introduction of the material to be ground; or on its periphery with a large number of inlet nozzles for the propellant gas, which nozzles are directed tangentially thereto inthe same direction, and in the center with an outlet opening for the discharge of the ground material and the expanded propellant gas.
  • the diameter of the grinding chamber can be about 50 to 1200 mm and its height about 25m 62 mm.
  • propellant nozzles the outlet openings of which may have a diameter of 1.4 to 6 mm.
  • propellants air, superheated steam or other gases of a pressure of about 3 to 10 atmospheres gauge are used.
  • the ground material is deparated in a subsequent cyclone with or without a filter.
  • Such jet mills are used particularly for very finely comminuting substances which are sensitive to heat and chemicals and-in which high requirements as to fineness and uniformity of the grain as well as purity are necessary.
  • many substances which absolutely require such a gentle grinding for instance plant protective agents, pharmaceutical substances, etc., cannot be dependably comminuted with a satisfactory quantitative output.
  • a crust is formed, predominantly in the outer zones of the grinding chamber, so that the feeding of the propellant and the removal of the fine dust become irregular and pieces of crust which have broken oil are contained in the final product.
  • This situation can some times be improved by strongly reducing the feed of the material to be ground while keeping the amount of propellant unchanged, by frequently opening and cleaning the grinding chamber and by drying the propellant before its introduction into the grinding chamber, which, however, impairs the economy of the grinding process.
  • Another object of the present invention is to provide a jet mill in which the lateral wall of the grinding space thereof is developed in a stepwise manner.
  • Another object of the present invention is to provide a mill having at the top of the grinding chamber, a device which makes possible a variable adjustment of the injector nozzle in such a manner that the horizontal angle between the axis of the nozzle and the radius of the grinding chamber is variable.
  • Still another object of the present invention is to provide a mill having a valve or a similar device which is so developed that it makes possible the closing of the discharge opening for the ground material and propellant one or more other openings which open into the grinding chamber being simultaneously exposed.
  • FIGS. 1 and 2 show schematically, by Way of example, of a preferred embodiment sections through the mill obtained when employing the inventive concept.
  • a grinding chamber A has an outer circular periphery and the interior has, for instance, three recessed portions forming circular steps, 10, 11 and 12 respectively.
  • a central outlet pipe B extends from the bottom of chamber A for the mixture of propellant of ground material, while a feed opening C for the material to be ground is mounted on eccentric disc H
  • the propellant which at the same time serves to feed the injector nozzle D disposed at the opening C, enters the mill at areas E, F andG and after emerging from the tangential nozzles or'boreholes d, e, f, and g,-expands down to a pressure slightly above atmospheric pressure.
  • connection cap B is tightly closed and the openings L in the tubular guide member M are exposed. Flushing or drying of the grinding chamber can now be elfected with any desired liquids, vapors or gases which are fed for instance to the connections D, E, F and G grinding chamber.
  • the grinding chamber may have merely two or more than three steps and the inlet nozzles can be present on all or only a few of the steps.
  • a jet mill for finely grinding solids comprising a cylindrical chamber, which'is provided with tangentially directed inlet nozzles for propellant gas, said nozzles being arranged on the periphery of the chamber, an injector nozzle directed tangentially in .the same direction as the nozzles for the introduction of the material to be ground,
  • said chamber having 'a central outlet opening for the discharge of the ground material .and of the expanded propellant gas, said chamber having a pair of eccentrically mounted covers'for variable adjustment of'the injector nozzle whereby the horizontalangle a between the nozzle axis and the radius of the grinding chamber is adjustable.
  • Ajet mill for the grinding or solids comprising a chamber having an axis and provided on the periphery with tangentially directedinlet nozzles for propellant gas;
  • aninjector nozzle 'on the t'opuof the chamber directed tangentially in the same direction as'the inlet nozzles for the introduction of the material to be ground, said chamber having'a central outlet opening for the discharge of the ground material and of the expanded propellant gas, and closure 'means for closing the outlet opening tor ground material and propellant, at least one opening in said closure means communicating with the grinding chamber being simultaneously exposed when said outlet :opening is being closed.
  • a jet mill for grinding solids comprising a chamber having an axis, an axially extending side wall, and a top wall transverse of said axis, said side wall having a substantially circular cross section decreasing stepwise in an axial direction away from said top wall; a plurality of tangentially disposed inlet nozzles in said chamber; injector nozzle means mounted on said top wall for injecting a material to be ground into said chamber in a tangential direction relative to said axis; and a discharge conduit axially communicating with said chamber.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Disintegrating Or Milling (AREA)
US8954A 1959-02-24 1960-02-16 Jet mills and the like Expired - Lifetime US3005594A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DESC025591 1959-02-24

Publications (1)

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US3005594A true US3005594A (en) 1961-10-24

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US (1) US3005594A (fr)
FR (1) FR1248777A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3178121A (en) * 1962-04-24 1965-04-13 Du Pont Process for comminuting grit in pigments and supersonic fluid energy mill therefor
US3223333A (en) * 1963-09-24 1965-12-14 Fluid Energy Proc And Equipmen Method for preparing liquid slurries and for dispersement thereof in polymeric substances
US3584797A (en) * 1970-03-11 1971-06-15 Fluid Energy Process Equip Multiple section fluid energy grinding mill
US3595486A (en) * 1969-11-24 1971-07-27 Fluid Energy Process Equip Treatment of granular solids by fluid energy mills
JPS4848610A (fr) * 1971-10-15 1973-07-10
US7398934B1 (en) * 2007-05-15 2008-07-15 E.I. Du Pont De Nemours And Company Deep-chamber, stepped, fluid-energy mill

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2032827A (en) * 1933-11-21 1936-03-03 Internat Pulverizing Corp Method of and apparatus for providing material in finely divided form
US2155697A (en) * 1936-10-02 1939-04-25 Albert Robert Wilson Apparatus for pulverizing minerals and other materials
US2257907A (en) * 1940-08-08 1941-10-07 Cliffs Dow Chemical Company Method of making activated carbon
US2690880A (en) * 1951-04-10 1954-10-05 Freeport Sulphur Co Rectilinear pulverizer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2032827A (en) * 1933-11-21 1936-03-03 Internat Pulverizing Corp Method of and apparatus for providing material in finely divided form
US2155697A (en) * 1936-10-02 1939-04-25 Albert Robert Wilson Apparatus for pulverizing minerals and other materials
US2257907A (en) * 1940-08-08 1941-10-07 Cliffs Dow Chemical Company Method of making activated carbon
US2690880A (en) * 1951-04-10 1954-10-05 Freeport Sulphur Co Rectilinear pulverizer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3178121A (en) * 1962-04-24 1965-04-13 Du Pont Process for comminuting grit in pigments and supersonic fluid energy mill therefor
US3223333A (en) * 1963-09-24 1965-12-14 Fluid Energy Proc And Equipmen Method for preparing liquid slurries and for dispersement thereof in polymeric substances
US3595486A (en) * 1969-11-24 1971-07-27 Fluid Energy Process Equip Treatment of granular solids by fluid energy mills
US3584797A (en) * 1970-03-11 1971-06-15 Fluid Energy Process Equip Multiple section fluid energy grinding mill
JPS4848610A (fr) * 1971-10-15 1973-07-10
US7398934B1 (en) * 2007-05-15 2008-07-15 E.I. Du Pont De Nemours And Company Deep-chamber, stepped, fluid-energy mill

Also Published As

Publication number Publication date
FR1248777A (fr) 1960-12-23

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