US2931582A - Apparatus for fine crushing - Google Patents

Description

April 1960 J. A. KYRIAZI 2,931,582

APPARATUS FOR FINE CRUSHING Filed Dec. 17, 1957 U'nited SEES- Patt fi APPARATUS FOR FINE CRUSHING Jean A. Kyriazi, Alexandria, Egypt Application December 17, 1957, Serial No. 793.423 Claims priority, application Belgium August 4, 1956 6 Claims. (Cl. 241-56) This invention relates to an apparatus for grinding and sizing of solid materials of the type in which the materials in a stream of air are hurled by a rotating member against a stationary member consisting of a peripheral annulus of longitudinal tubular pockets where the particles are reduced both by reciprocal grinding and by impact. The efficiency of this type of apparatus is determined by the quantity of air going to the pockets and by the length of time these particles stay in the pockets. These two efiiciency conditions oppose each other and the air'introduced into the pockets tends to escape immediately carrying away the particles of materials without leaving them time for sizing other than through direct impact against the walls of the pockets. A large amount of air is necessary to accelerate, to move and to size the particles. The first object of the instant invention is to enable the introduction of large quantities of. air into the tubular pockets and at the same time to: retain the particles which are insufficiently ground in th pockets.

In this type of apparatus the amount of air necessary is produced by fans. The particles are accelerated both by air and by the blades of fans and the separation is brought about by the resulting direction given to a particle as it crosses a radial fan from the periphery to the center. The present invention is characterized by the provision of a gap between each of the tubular pockets so that a portion of the air flung into the tubular pockets- 7 by centrifugal action may pass through the gaps and join a suction air flow surrounding the annulus of tubular pockets, which are accordingly installed at a distance from the inside walls of the grinding chamber of the stator so that an air space surrounds the peripheral annulus of the. tubular pockets. The first object of the instant invention is realized by the above double characteristics. Another object of the instant invention is to prevent the particles from concentrating in the; bottom of the apparatus and clogging up the bottom pockets of said apparatus. A bottom opening in the stator serves to permit removal from the circuit of the particles which have lost their velocity.

Still another object is to adapt to the apparatus a sizing system to return the insufliciently ground particles to the grinding zone.

The practical embodiment of this invention is described, by way of example, in the following specification and in the attached figure in which:

Figure 1 is a longitudinal section of an apparatus according to the invention; and

Figure 2 is a section on line 2--2 through the peripheral annulus of tubes in the apparatus of Figure 1.

The apparatus described in these figures consists of a rotor shaft 1 running through a grinding chamber 14 and a suction chamber 12. The grinding chamber comprises a stator 2, a lateral wall 23 having an air inlet therein, a loading hopper 3 mounted on the wall 23 over opening 23' therein, and a peripheral ring of openended tubular pockets. forming with the wall an air casing. The pockets 10 are each separated by a small a peripheral angle iron 13 welded to the pockets at"27.'

An opening 9 is provided at the bottom of the grinding chamber. The rotor is a projecting fanand comprises a projection disc 4 on one side fitted at'its periphery with blades 7 joined by an annulus 6; On the other side of the disc are mounted blades 15. On the 'shaft'l between the disc 4 and the wall 24 of stator 2 separating the chambers 12 and 14- a separating fan 17' having vanes is fixed. The lateral flange 21of a connecting t'u'be'18 connected to fan 17, and the separating wall24 is sealed to the tube 18 by means of packing 16. The connect ing tube 18 is connected with a centrifugal exhaust device 19 mounted on the shaft 1 in the suction chamber 12. A discharge nozzle 20 is mounted on chamber 12. An air duct 8 open at its lower end is mounted on wall 23 and leads from opening 9 to air inlet 5.

In operation, a first double air current isp'rodu'ced.

one along the inside wall of the stator, and the other through the fan formed by a disc 4 and blades 7; 'From apoint radially inwardly of the tubular pockets the compressed air of the second current escapes through the gaps between the tubes and joins the peripheral air current along the stator wall, and the remaining air mixes with the'first current at the outlet of the pockets. The air current passes through the vanes of the separating fan 17 and is ejected through the escape nozzle 20 of suction chamber.

'The material introduced into the loading .hopper' 3- flows into the projecting fan through opening 23' and is violently projected by the blades 7. The particles whirl around the pockets 10, where by reciprocal wear and impact they are ground. The fines are carried away with the compressed air current passing through,

the gaps between the pockets. The particles remaining in the tubes 10.are projected at the open end of-' the tubes at high speed into the separating wall 24-which has a deflecting surface 24' where a first separation takesplace. face and are directed against. the projection disc 4 which throws them against the rounded wall of the grinding chamber to the center of the annulus 6'and they are taken up again in the grinding circuit. particles which have lost speed fall into the bottom of the apparatus where they are'removed by gravitythrough the discharge opening 9. The duct 8 servesto bring back into the circuit the air 1 loaded with fine' particles escaping through the discharge opening 9m- The finely ground material coming out of the tubular pockets will, on the other hand, be sucked through the separating fan 17 through the circular opening serving as the communication between the grinding and suction chambers. The blades of this fan strike the particles in the stream of air being drawn through it, and the resultant force acting on the particles is the combined force imparted to them by the air stream and by the blades of the fan. Thus the larger particles will be knocked out of the stream of air flowing through the fan and the smaller particles will remain in the stream and be carried through the fan. The larger particles will fall back into the grinding chamber 14 to be collected as described above. A portion of air escapes radially from the pockets 10 through the gaps separating the pockets, carrying along particles small enough not to be retained in the pockets by the cyclonic action of the inside walls of the pockets. The peripheral portion of the grinding chamber 14 being in communion iiatentedt App 1 5 The coarse particles follow the defiectingHsur- Thetion with the suction system, this radial 'escapement is encouraged by the intensive whirling movement enter 'ing the pockets slightly. This installation enables the introduction of. large quantities. of air and at the same.

in the bottomaof the grinding chamber and eliminate them either through the opened orifice in' the bottom of; the apparatus, in the case where it is desired to remove thegi it contained in the material to be ground and which concentratesin the particles gathered in the bottom of the device, o r by making those particles return to the center oi the projccting fan with the aid of an appropriate device.

-The third object of the instant invention is accompiished by the deflecting surface which first performs a sizing and then a direction of the particles sized against the fan by which they are returned to the center of the projecting fan.

The constructional details of this invention may vary. The pockets may be replaced partially or completely by a fiat, or grooved, or corrugated surface. of pockets and bladescan be adjusted so as to obtain ultrasonic vibrations with an easier subsequent recovery re the materiah The suction system may be replaced by another. systern forminga part of or independent from the apparatus. The turbo-suction device can be designed to op-' erate simultaneously as a centrifugal collecting device with 'a bottom airtight discharge. The apparatus may consist of two pulverizing chambers placed at both sides ofa central suction chamber.

The separation device may be limited to the deflectors only. The fan for separation can be replaced by a screen. only, the air transporting the tines through the gaps and the coarse particles being recirculated.

For grinding low melting point material a double shell may-surround the annulus of pockets and be filled with cooling medium.

The apparatus according to this invention may be used as a grinder permitting the grinding of a wide range of material, as a grinder and sizing unit, as a grinder and degritting apparatus, as a burner and grinder for solid.

fuels, as a grinder-mixer or mixer unit, as a grindersizing and recuperation unit, etc.

By: eliminating the material ejected to the base of the not cause any clogging, while at the same time they can The separation may be e ected by the pockets:

bottom airtight discharge it is possible to eliect separations by degree of grindability or by the dilterentiation of the shapes, by alternating or sharpening sizing devices.

I claim:

1. An apparatus for grinding material comprising a grinding chamber having an air and a material inlet thereto, a rotor rotatably mounted therein, a fixed annulus mounted coaxially around said rotor and spaced radially therefrom, said annulus being spaced radially in- I Because of the air chamber surrounding the ring of pocket s,it is easy to recuperate the particles losing speed The number between said grinding chamber and said air evacuation system.

3. An apparatus for grinding material comprising a grinding chamber, a suction chamber adjacent said grinding' chamber]. a separating wall between said chambers,

a shaft rotatably mounted through said chambers, a projecting fan mounted on said shaft in said grinding chamher and having a projecting disc forming a part thereof, said grinding chamber having an air inlet coaxial with said shaft on one side of said projecting disc, a hopper on said grinding chamber, an annulus mounted in said grinding chamber spaced from the walls of said chamber and surrounding said projecting fan and spaced therefrom and having a plurality of open-ended tubular pockets therein, said pockets opening toward said projecting turbine and'being spaced from each other, said grinding chamber further having an evacuation outlet coaxial with said shaft in said separating wall, separating means on said shaft in said grinding chamber on the opposite side of said projecting disc from said air inlet,

a tube connecting said separating means and extending through said evacuation outlet and rotatably sealed with said separating wall, and a suction fan mounted on said separating means comprises a separating fan.

-5. An apparatus as claimed in claim 3 in which said:

separating wall has at least one circular deflector thereon.

machine, or by efiecting a separating action by the sep-.

aratiug fan-or by installing separators in series with a 6 An apparatus as claimed in claim 3 in which a part of said annulus consists of a plane surface.

References Cited in the file of this patent UNITED STATES PATENTS

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