Classifications

• • 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
  • B02C19/065—Jet mills of the opposed-jet type

Definitions

• This invention relates to a pulverizing chamber of a counter et pulverizer, which chamber is mainly cylindrical and at least two conically arranged, to a common point directed accelerating nozzles terminate at it, the inner walls of which pulverizing chamber are made of a wearing-resistant special material.
• the pulverization occurs mainly autogenously in a pulverizing chamber having a small volume, into which the material to be pulverized flows at a high speed via the accelerating nozzles of the pulverizer and supported by a working gas.
• the gas/material jets impact against eacht other at their common intersection, whereby the pulverization of material particles is caused by the impact effect.
• the pulverizing nozzles are arranged slightly conically relative to each other such that the material particles would penetrate into the opposite nozzles or nozzle to an extent as low as possible.
• the particles which do not crush at the intersection of the gas/particle jets, impact against a wall of the pulverizing chamber at a high speed, which causes wearing of the wall especially in those parts of the pulverizing chamber, which are located on the opposite side of the orifice of the nozzle, and in the axial direction between the intersection of the gas/material jets and the outlet opening of the pulverizing chamber. Because of this, the pulverizing chamber must be made of especially wearing- resistant special materials, which are expensive and difficult to fabricate and treat.
• the object of the present invention is the entension of the operating life and the facilitation of the fabrica ⁇ tion of a pulverizing chamber of a counterjet pulverizer.
• the pulverizing chamber comprises a fixed basal part, in the vicinity of whose open end the accelerating nozzles terminate, as well as an exchangeable wearing ring mounted rotatably on this open end, whereby the contact surfaces of the fixed part and the wearing ring are formed as sliding surfaces.
• Fig. 1 is an axial sectional view of the inventive pulverizing chamber, in which certain alternative embodiments of different components are shown by way of example, and
• Fig. 2 shows the pulverizing chamber of Fig. 1 seen from the top.
• Fig. 3 is a more detailed side elevation of one certain preferred embodiment of the invention as an axial section, in which the attachment of the accelera ⁇ tion nozzle is shown.
• the pulverizing chamber of the counterjet pulverizer is mainly cylindrical and at least two conically arranged, to a common point 1 directed accelerating nozzles 2 terminate at it, which are arranged slightly conically relative to each other such that the material particles would penetrate into the opposite nozzle 1 to an extent as low as possible.
• a common point 1 directed accelerating nozzles 2 terminates at it, which are arranged slightly conically relative to each other such that the material particles would penetrate into the opposite nozzle 1 to an extent as low as possible.
• an actual wearing zone is formed.
• the inner walls of the pulveri ⁇ zing chamber are subjedted to a very high wearing stress at least at those points, against which the material particles penetrating uncrushed through the pulverizing zone 2 impact. Because of this, the inner walls of the pulverizing chamber must be made of especially wearing- resistant special materials, which are expensive and difficult to fabricate and treat.
• the pulverizing chamber is fabricated such that it comprises a fixed basal part 3, in the vicinity of whose open end are arranged inlet openings 4 for the orifices of the accelerating nozzles 1.
• an exchangeable wearing ring 5 is rotatably arranged, whereby the contact surfaces of the basal part 3 and the wearing ring 5 are formed as sliding surfaces 6.
• the inventive pulverizing chamber is used such that at intervals of a couple of hundreds of operating hours, depending on the material to be pulverized, the wearing ring 5 of the pulverizing chamber is rotated by some degrees around its axis, whereby worn sections move away from the point where the wearing is at its highest.
• the stepwise rotation of the wearing rings can be performed so many times at said intervals that the first worn sections enter the following point subjected to heavy wearing, whereby the wearing ring must be replaced with a new one. If the wearing in the axial direction is very limited, it is preferable to design both end surfaces of the wearing ring 5 such that the wearing ring 5 can still be turned around, whereby the operating life of the wearing ring is duplicated.
• the sliding surfaces 6 have to be directed so that the gas/material jets rapidly flowing from the accelerating nozzle 1 cannot penetrate into them, whereby the most simple alternative is to arrange them completely radial, but in this case the sliding surfaces 6 do not facilitate the concentration of the pulverizing-chamber parts 3 and 5.
• the sliding surfaces 6 may be e.g. designed in the form of a truncated cone, or if a very accurate concentration is necessary, the sliding surfaces 6 may be designed such that one sliding surface 6 has a longitudinal groove and the other, or opposite sliding surface 6 has a ridge that completely fits into this groove, as shown on the right-sided side wall of Fig. 1.
• the basal part 3 may be fabricated preferably from steel.
• the pulverizing chamber may be comprized of several wearing rings 5, whereby the wearing ring, which is subjected to heavier wearing, is rotated more often and replaced at more frequent intervals than a wearing ring 5 located in a more protected space.
• the entire pulverizing chamber is mounted inside a separate frame structure 8.
• the drawing shows two alternative embodiments of how the accelerating nozzles 1 are brought into the pulverizing chamber.
• the material to be pulverized is a heavily- wearing material
• the right-sided solution is preferable, since it is capable of protecting the ends of the accelerating nozzles 1 from wearing excessively.
• a softer material is pulverized or if the material to be pulverized is by its particle size very fine-powdered, the left-sided solution is better, whereby also the ends of the accelerating nozzles may be brought closer to the pulverizing zone.
• the pulverizing chamber may be made by its construction either fully circular or brought into a form of a regular polygon. In the latter case, the number of sides of the polygon defines how many degrees the wearing ring must bo rotated at a time.
• the attachment of the accelerating nozzles 1 to the frame structure 8 and an accurate concentration with respect to the intersection 2 may be preferably realized such that at each end of each accelerating nozzle 1 is arranged a pair of 0-rings 10, surrounding the accelerating nozzle 1 and adjustable by means of a clamping ring 9.
• This solution also effectively prevents the entry of dust into the surrounding space at the same time as the structure acts as an effective damper for vibrations and a possible resonance.

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• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Disintegrating Or Milling (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8531613

Family Applications (1)

Country Status (5)

Cited By (6)

Families Citing this family (1)

Citations (1)

• 1990
  • 1990-12-19 FI FI906266A patent/FI86514C/fi not_active IP Right Cessation
• 1991
  • 1991-12-19 CA CA 2098500 patent/CA2098500A1/en not_active Abandoned
  • 1991-12-19 EP EP19920900697 patent/EP0561897A1/en not_active Withdrawn
  • 1991-12-19 WO PCT/FI1991/000400 patent/WO1992011090A1/en not_active Application Discontinuation
  • 1991-12-19 AU AU90601/91A patent/AU9060191A/en not_active Abandoned

Patent Citations (1)

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