CA1198401A - Pressure-chamber grinder - Google Patents
Pressure-chamber grinderInfo
- Publication number
- CA1198401A CA1198401A CA000418370A CA418370A CA1198401A CA 1198401 A CA1198401 A CA 1198401A CA 000418370 A CA000418370 A CA 000418370A CA 418370 A CA418370 A CA 418370A CA 1198401 A CA1198401 A CA 1198401A
- Authority
- CA
- Canada
- Prior art keywords
- grinding
- chamber
- housing
- gas
- classifier
- Prior art date
- 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
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- Disintegrating Or Milling (AREA)
Abstract
(57) Abstract of the Disclosure:
A pressure-chamber grinder which comprises a grinder chamber (1) of substantially circular section, which chamber is provided with a feed opening (3) for the material to be ground, fed as a gas-light plug, and the opposite end of which chamber is provided with an outlet opening (5) for the material ground. Tangentially directed grinding-gas nozzles (7) are fitted as uniformly spaced around the entire circumference of the mantle face (6) of the grinder chamber, or at least of part of same. The object of the present invention is to force the entire material flow to rush into every grinding zone. This has been achieved so that the grinder chamber (1) is, by means of a partition wall (8), divided into a pre-grinding chamber (9) and a grinding chamber (10) proper, the said chambers being interconnected by means of at least two Laval nozzles (11) passing through the partition wall and forming an angle with each other, whereat the material-gas jets rushing through these nozzles at a supersonic speed collide against each other at the outlet side of the Laval nozzles (11), thus forming there a grinding zone, to which zone the coarse fraction separated in a classifier (17) connected to the outlet opening (5) of the grinding chamber (10) is returned.
(Fig. 1)
A pressure-chamber grinder which comprises a grinder chamber (1) of substantially circular section, which chamber is provided with a feed opening (3) for the material to be ground, fed as a gas-light plug, and the opposite end of which chamber is provided with an outlet opening (5) for the material ground. Tangentially directed grinding-gas nozzles (7) are fitted as uniformly spaced around the entire circumference of the mantle face (6) of the grinder chamber, or at least of part of same. The object of the present invention is to force the entire material flow to rush into every grinding zone. This has been achieved so that the grinder chamber (1) is, by means of a partition wall (8), divided into a pre-grinding chamber (9) and a grinding chamber (10) proper, the said chambers being interconnected by means of at least two Laval nozzles (11) passing through the partition wall and forming an angle with each other, whereat the material-gas jets rushing through these nozzles at a supersonic speed collide against each other at the outlet side of the Laval nozzles (11), thus forming there a grinding zone, to which zone the coarse fraction separated in a classifier (17) connected to the outlet opening (5) of the grinding chamber (10) is returned.
(Fig. 1)
Description
~98~
Pressure-chamber grinder The present invention is concerned with a pressl~re-c~amber grinder in which the maternal to be ground, such as talc, bonus, titanium oxide, or soot, is ground to ultra-ine-grain particles by mans of grinding gas. The grinder comprises a grinder corollary of substantially circular section, and the chat or is provided with a feed opening for the material to be ground, fed as a gas-tight plug, as well as with tangent tidally directed nozzles for the grinding gas, pitted as uniformly spaced on the mantle face or at least on a part of same. At the opposite end of the grinder, there is an outlet opening for the material ground, a classic lien being connected to the said opening, from which classifier the coarse fraction can be returned into the grinder. As the grinding gas is used compressed air or water vapour, favorably superheated water vapour.
In an attempt to improve the energy economy of jet grinders, the first operation has been to replace the ejector feeder of a conventional grinder by a so-called plug feeder, whereby energy economies of us to 10 to 15 per cent have been achieved.
In practice, it has, however, been noticed that a grinder constructed in view of the ejector feeder does not operate fully satisfactorily when a plug feeder is used. This is why, for example, a jet grinder has been developed whose grinder chanter has the shape of an oblong box through which the material to be ground passes, the grinding-gas nozzles being arranged along two opposite walls of the grinder chamber as directed so that the grinding-gas jet coming from each nozzle acts upon the material to be ground in a way both grinding and changing the direction of flow. The efficiency of the apparatus is relatively good, because the material is subjected to the grinding effect at each nozzle. However, there is the drawback that part ok of the material to be ground can flow past the nozzle without being at all subjected to the grinding effect.
The object of -the present invention is also -to eliminate this drawback by developing an apparatus in which -the entire material flow is forced to pass through several grinding zones without being Abel to by-pass them. The pressure-chamber grinder in accordance with -the invention is characterized in that it comprises: a housing defining a space and having a mantle face extending around the space; a partition wall connected in the housing dividing the housing space into a regrinding chamber and a main grinding chamber and extending substantially transfer-sly to the mantle face; the housing including a portion defining a regrinding portion having a cross-sectional area larger than the regrinding chamber, the regrinding portion being connected to the regrinding chamfer; material feed means connected to the housing and communicating with the regrinding portion for feeding a gas-tight plug of material to the regrinding portion;
a plurality of tangentially directed nozzles, uniformly spaced around the mantle face and connected to the housing for supplying grinding gas under pressure to the regrinding portion of the housing; a pair of concentric walls connected to the housing for separating the regrinding portion from the regrinding chamber, each of the concentric walls extending axially by at least one-half an overall height of the regrinding portion;
the housing having an outlet communicating with the main grinding chamber for discharging at least partially ground material from the main grinding chamber; at least two level nozzles extending through the partition wall extending toward a centerline of -the . - 2 -., main grinding chamber and forming an angle with each other, -the level nozzles cornmunica-tiny with the regrinding chamber and with -the main grinding chamber and structured to pass rrlate-rial with grinding gas from the pre-yrinding chamber to the main grinding chamber at- supersonic speed, the main grinding chamber including a grinding zone adjacent an outlet of each of -the two level nozzles at which material and grinding gas collide at supersonic speed, the grinding zone spaced from the outlet; and a classifier connected to the housing outlet and having a classifier outlet for discharging material and grinding gas into the grinding zone, the classifier separating a coarse fraction from a fine fraction of material which has been ground in the pro and main grinding chambers, supplying the coarse fraction to the grinding zone and supplying the fine fraction out of the housing.
The following is a description by way of example of an embodiment of the invention, reference being had to the accompanying drawings in which:-Figure l shows a side view of the apparatus; and Figure 2 shows a section along line A-A in Figure 1.
The pressure-chamber grinder shown comprises a grinder chamber 1 of substantially circular section, which is provided with a feed opening 3 for the material to be ground, fed as a gaslight plug, and whose opposite end is provided with an outlet opening 5 for the material ground. Tangentially directed grinding-gas nozzles 7 are arranged as uniformly spaced around -the entire circumference of the mantle face over at least a part pa -I
of the mantle face 6 of the! grinder chamber 1. The oblong grinder chamber is, by means of a partition wall 8, divided into a regrinding chamber 9 and a grinding chamber 10 proper, which chambers are inter-connected by means of at least two Level nozzles forming an angle with each other. The material-gas jets rushing through the nozzles at a supersonic speed intersect each other in the grinding chamber 10 placed immediately at the outlet side of the Level nozzles 11, at which point a zone of collision of the material particles to be ground is formed. The coarse fraction coming from the classifier 17 connected to the outlet opening 5 of the grinding chamber 10 is returned to this zone.
In view of efficient operation of the Papa-fetus, it is essential that the collision zone is formed immediately in the proximity of the outlet side of the Level nozzles 11 in order that the speed of the gas flows should not have time to be lowered. The location of the collision point and the extent of the collision zone can be affected by means of the angle between the Level nozzles 11, which angle may vary within the limits of about 60 Tao, whereat angles within the range of about 90 to 120 have proved most advantageous.
The feed opining 3 may be located at any place near one end of the grinder chamber 1, preferably close to the mantle face 6, so that the material to be ground, fed into the grinder chamber by means of the plug feeder, is immediately subjected -to the action of the grinding-gas flows coming from the nozzles 7.
One should aim at the circumstance that the inlet angle between the material-gas jets discharged through the Level nozzles 11 is such that a favorable material circulation is produced in the grinder.
If necessary, it is possible to connect two or more grinder units in series. In such a case, a ., requirement is that a grinding gas of sufficiently high pressure is available in order that the speed of the material-gas jet passing through each Level nozzle 11 should become supersonic.
At least a part of the marltle face 6 of the grinding chamber 10 provide with the outlet opening 5 is conical so that the cross-sectional area of the grinding chamber 10 becomes smaller towards the outlet opening 5, whereat the speed of the material-gas flow rushing out of the grinder becomes higher.
In order to intensify the material-gas flow taking place in the regrinding chamber 9, it is advantageous to shape each partition wall 8, in the direction of inlet of the flow either conical or convex, whereat the feed openings of the Level nozzles 11 placed in the partition wall 8 may be placed entirely at the face of the partition wall 8. When the partition walls 8 are shaped in this way, unnecessary recesses and pro-jetting portions are avoided at the same time, which 2Q recesses and projections would be subject to intensive wear According to a preferred embodiment, the end of the grinder chamber 1 placed next to the feed opening 3 is provided with a regrinding portion 14, whose cross-sectional area is larger than that of the rest of ` the grinder chamber 1 and whose mantle face is provided with tangentially directed grinding gas nozzles 7. The feed opening 3 of the grinder is placed at the proximity of the mantle face of the regrinding portion 14. In the solution shown in Fig. 1, the feed opening 3, to which the feeder pipe coming from the plug feeder and provided with a screw conveyor 4 is connected, is located in the end wall 2. It is recommended that the material to be ground is, before it is fed into the regrinding portion 14, by means of a separate grind-ing-gas jet, accelerated to the same speed as the speed of the material-gas f low circulating in the regrinding portion 14.
To each end wall 2, 15 of the regrinding portion 14, at least one partition wall 6, 12 is attached which is parallel to the circumference and which art lion walls are concentric and have a height of at least half the overall height of the regrinding portiorl 14 so that they are slightly overlapping each other. The junction of these partition walls 6, 12 is to operate as some sort of obstacle for the material flow fluidized in the pre-grindirlg portion 14, whereat the regrinding and classification taking place in this portion are intensified.
In order to simplify the entire grinder Papa-fetus, it is advantageously possible to place the classifier 17 in the regrinding chamber 9 so that its outlet end for the coarse fraction passes through the partition wall 8 at the centre point of this wall and extends to the zone of collision of the material-gas jets rushing through the Level nozzles lo so that the coarse fraction coming out of the classifier 17 is immediately subjected to a new yrindiny action. The classifier 17, which is preferably of the cyclone type, is via a connecting pipe 16 connected to the outlet opening 5 of the grinding chamber 10, from which the round material-gas flow is passed into the classifier ` . 17 tangentially. In the classifier 17, the coarse fraction is separated from the rest of the material flow by means of the centrifugal force and returned into the said collision or grinding zone. The fine I fraction is passed through an outlet pipe 18 provided at the other end of the classifies 17 possibly into a subsequent pressure-chamber grinder 7 operating at a lower pressure, or straight into a product tank.
By providing the tangentially directed grinding-gas nozzles 7 only at the mantle face of the regrinding portion 14, the said nozzles 7 being con netted to the grinding-gas distributor beam 13 sun-fj rounding the regrinding portion 19, an advantageously operating grinder is obtained into which high-pressure grinding gas it fed exclusively through the said nozzles 7.
The grinder chatter 1 may be positioned either vertically or horizontally, depending on the type of classifier 17 used and on the location of the classifier.
In connection with a pressure-chamber grinder yin accordance with Fig. 1, as the grinding gas is pro-fireball used superheated water vapour at a pressure of at least 7 bars, the vapour being fed into the prey grinding portion 14 through the nozzles 7 and a post-live pressure of at least 3 bars being maintained in the regrinding portion 14 by means of the said vapour.
In the subsequent grinding chamber lo into which the material-gas flow rushes at a supersonic speed through the Level nozzles 11, appropriately a positive pressure of about 0.05 to 0.1 bar is maintained, the material-gas mixture being passed from the said chamber to the classifier 17.
It is evident that the various details of the pressure-chamber grinder may be designed in many different ways within the scope of the invention.
Pressure-chamber grinder The present invention is concerned with a pressl~re-c~amber grinder in which the maternal to be ground, such as talc, bonus, titanium oxide, or soot, is ground to ultra-ine-grain particles by mans of grinding gas. The grinder comprises a grinder corollary of substantially circular section, and the chat or is provided with a feed opening for the material to be ground, fed as a gas-tight plug, as well as with tangent tidally directed nozzles for the grinding gas, pitted as uniformly spaced on the mantle face or at least on a part of same. At the opposite end of the grinder, there is an outlet opening for the material ground, a classic lien being connected to the said opening, from which classifier the coarse fraction can be returned into the grinder. As the grinding gas is used compressed air or water vapour, favorably superheated water vapour.
In an attempt to improve the energy economy of jet grinders, the first operation has been to replace the ejector feeder of a conventional grinder by a so-called plug feeder, whereby energy economies of us to 10 to 15 per cent have been achieved.
In practice, it has, however, been noticed that a grinder constructed in view of the ejector feeder does not operate fully satisfactorily when a plug feeder is used. This is why, for example, a jet grinder has been developed whose grinder chanter has the shape of an oblong box through which the material to be ground passes, the grinding-gas nozzles being arranged along two opposite walls of the grinder chamber as directed so that the grinding-gas jet coming from each nozzle acts upon the material to be ground in a way both grinding and changing the direction of flow. The efficiency of the apparatus is relatively good, because the material is subjected to the grinding effect at each nozzle. However, there is the drawback that part ok of the material to be ground can flow past the nozzle without being at all subjected to the grinding effect.
The object of -the present invention is also -to eliminate this drawback by developing an apparatus in which -the entire material flow is forced to pass through several grinding zones without being Abel to by-pass them. The pressure-chamber grinder in accordance with -the invention is characterized in that it comprises: a housing defining a space and having a mantle face extending around the space; a partition wall connected in the housing dividing the housing space into a regrinding chamber and a main grinding chamber and extending substantially transfer-sly to the mantle face; the housing including a portion defining a regrinding portion having a cross-sectional area larger than the regrinding chamber, the regrinding portion being connected to the regrinding chamfer; material feed means connected to the housing and communicating with the regrinding portion for feeding a gas-tight plug of material to the regrinding portion;
a plurality of tangentially directed nozzles, uniformly spaced around the mantle face and connected to the housing for supplying grinding gas under pressure to the regrinding portion of the housing; a pair of concentric walls connected to the housing for separating the regrinding portion from the regrinding chamber, each of the concentric walls extending axially by at least one-half an overall height of the regrinding portion;
the housing having an outlet communicating with the main grinding chamber for discharging at least partially ground material from the main grinding chamber; at least two level nozzles extending through the partition wall extending toward a centerline of -the . - 2 -., main grinding chamber and forming an angle with each other, -the level nozzles cornmunica-tiny with the regrinding chamber and with -the main grinding chamber and structured to pass rrlate-rial with grinding gas from the pre-yrinding chamber to the main grinding chamber at- supersonic speed, the main grinding chamber including a grinding zone adjacent an outlet of each of -the two level nozzles at which material and grinding gas collide at supersonic speed, the grinding zone spaced from the outlet; and a classifier connected to the housing outlet and having a classifier outlet for discharging material and grinding gas into the grinding zone, the classifier separating a coarse fraction from a fine fraction of material which has been ground in the pro and main grinding chambers, supplying the coarse fraction to the grinding zone and supplying the fine fraction out of the housing.
The following is a description by way of example of an embodiment of the invention, reference being had to the accompanying drawings in which:-Figure l shows a side view of the apparatus; and Figure 2 shows a section along line A-A in Figure 1.
The pressure-chamber grinder shown comprises a grinder chamber 1 of substantially circular section, which is provided with a feed opening 3 for the material to be ground, fed as a gaslight plug, and whose opposite end is provided with an outlet opening 5 for the material ground. Tangentially directed grinding-gas nozzles 7 are arranged as uniformly spaced around -the entire circumference of the mantle face over at least a part pa -I
of the mantle face 6 of the! grinder chamber 1. The oblong grinder chamber is, by means of a partition wall 8, divided into a regrinding chamber 9 and a grinding chamber 10 proper, which chambers are inter-connected by means of at least two Level nozzles forming an angle with each other. The material-gas jets rushing through the nozzles at a supersonic speed intersect each other in the grinding chamber 10 placed immediately at the outlet side of the Level nozzles 11, at which point a zone of collision of the material particles to be ground is formed. The coarse fraction coming from the classifier 17 connected to the outlet opening 5 of the grinding chamber 10 is returned to this zone.
In view of efficient operation of the Papa-fetus, it is essential that the collision zone is formed immediately in the proximity of the outlet side of the Level nozzles 11 in order that the speed of the gas flows should not have time to be lowered. The location of the collision point and the extent of the collision zone can be affected by means of the angle between the Level nozzles 11, which angle may vary within the limits of about 60 Tao, whereat angles within the range of about 90 to 120 have proved most advantageous.
The feed opining 3 may be located at any place near one end of the grinder chamber 1, preferably close to the mantle face 6, so that the material to be ground, fed into the grinder chamber by means of the plug feeder, is immediately subjected -to the action of the grinding-gas flows coming from the nozzles 7.
One should aim at the circumstance that the inlet angle between the material-gas jets discharged through the Level nozzles 11 is such that a favorable material circulation is produced in the grinder.
If necessary, it is possible to connect two or more grinder units in series. In such a case, a ., requirement is that a grinding gas of sufficiently high pressure is available in order that the speed of the material-gas jet passing through each Level nozzle 11 should become supersonic.
At least a part of the marltle face 6 of the grinding chamber 10 provide with the outlet opening 5 is conical so that the cross-sectional area of the grinding chamber 10 becomes smaller towards the outlet opening 5, whereat the speed of the material-gas flow rushing out of the grinder becomes higher.
In order to intensify the material-gas flow taking place in the regrinding chamber 9, it is advantageous to shape each partition wall 8, in the direction of inlet of the flow either conical or convex, whereat the feed openings of the Level nozzles 11 placed in the partition wall 8 may be placed entirely at the face of the partition wall 8. When the partition walls 8 are shaped in this way, unnecessary recesses and pro-jetting portions are avoided at the same time, which 2Q recesses and projections would be subject to intensive wear According to a preferred embodiment, the end of the grinder chamber 1 placed next to the feed opening 3 is provided with a regrinding portion 14, whose cross-sectional area is larger than that of the rest of ` the grinder chamber 1 and whose mantle face is provided with tangentially directed grinding gas nozzles 7. The feed opening 3 of the grinder is placed at the proximity of the mantle face of the regrinding portion 14. In the solution shown in Fig. 1, the feed opening 3, to which the feeder pipe coming from the plug feeder and provided with a screw conveyor 4 is connected, is located in the end wall 2. It is recommended that the material to be ground is, before it is fed into the regrinding portion 14, by means of a separate grind-ing-gas jet, accelerated to the same speed as the speed of the material-gas f low circulating in the regrinding portion 14.
To each end wall 2, 15 of the regrinding portion 14, at least one partition wall 6, 12 is attached which is parallel to the circumference and which art lion walls are concentric and have a height of at least half the overall height of the regrinding portiorl 14 so that they are slightly overlapping each other. The junction of these partition walls 6, 12 is to operate as some sort of obstacle for the material flow fluidized in the pre-grindirlg portion 14, whereat the regrinding and classification taking place in this portion are intensified.
In order to simplify the entire grinder Papa-fetus, it is advantageously possible to place the classifier 17 in the regrinding chamber 9 so that its outlet end for the coarse fraction passes through the partition wall 8 at the centre point of this wall and extends to the zone of collision of the material-gas jets rushing through the Level nozzles lo so that the coarse fraction coming out of the classifier 17 is immediately subjected to a new yrindiny action. The classifier 17, which is preferably of the cyclone type, is via a connecting pipe 16 connected to the outlet opening 5 of the grinding chamber 10, from which the round material-gas flow is passed into the classifier ` . 17 tangentially. In the classifier 17, the coarse fraction is separated from the rest of the material flow by means of the centrifugal force and returned into the said collision or grinding zone. The fine I fraction is passed through an outlet pipe 18 provided at the other end of the classifies 17 possibly into a subsequent pressure-chamber grinder 7 operating at a lower pressure, or straight into a product tank.
By providing the tangentially directed grinding-gas nozzles 7 only at the mantle face of the regrinding portion 14, the said nozzles 7 being con netted to the grinding-gas distributor beam 13 sun-fj rounding the regrinding portion 19, an advantageously operating grinder is obtained into which high-pressure grinding gas it fed exclusively through the said nozzles 7.
The grinder chatter 1 may be positioned either vertically or horizontally, depending on the type of classifier 17 used and on the location of the classifier.
In connection with a pressure-chamber grinder yin accordance with Fig. 1, as the grinding gas is pro-fireball used superheated water vapour at a pressure of at least 7 bars, the vapour being fed into the prey grinding portion 14 through the nozzles 7 and a post-live pressure of at least 3 bars being maintained in the regrinding portion 14 by means of the said vapour.
In the subsequent grinding chamber lo into which the material-gas flow rushes at a supersonic speed through the Level nozzles 11, appropriately a positive pressure of about 0.05 to 0.1 bar is maintained, the material-gas mixture being passed from the said chamber to the classifier 17.
It is evident that the various details of the pressure-chamber grinder may be designed in many different ways within the scope of the invention.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pressure chamber grinder for grinding material into ultrafine grain particles by means of grinding gas comprising:
a housing defining a space and having a mantle face extending around said space;
a partition wall connected in said housing dividing said housing space into a pre-grinding chamber and a main grinding chamber and extending substantially transversely to said mantle face;
said housing including a portion defining a pregrin-ding portion having a cross-sectional area larger than said pre-grinding chamber, said pre-grinding portion being con-nected to said pre-grinding chamber;
material feed means connected to said housing and communicating with said pre-grinding portion for feeding a gas-tight plug of material to said pre-grinding portion;
a plurality of tangentially directed nozzles, uni-formly spaced around the mantle face and connected to said housing for supplying grinding gas under pressure to said pre-grinding portion of said housing;
a pair of concentric walls connected to said housing for separating said pre-grinding portion from said pre-grinding chamber, each of said concentric walls extending axially by at least one-half an overall height of said pre-grinding portion;
said housing having an outlet communicating with said main grinding chamber for discharging at least partial ly ground material from said main grinding chamber;
at least two laval nozzles extending through said partition wall extending toward a centerline of said main grinding chamber and forming an angle with each other, said laval nozzles communicating with said pre-grinding chamber and with said main grinding chamber and structured to pass material with grinding gas from said pre-grinding chamber to said main grinding chamber at supersonic speed, said main grinding chamber including a grinding zone adjacent an out-let of each of said two laval nozzlesat which material and grinding gas collide at supersonic speed, said grinding zone spaced from said outlet; and a classifier connected to said housing outlet and having a classifier outlet for discharging material and grin-ding gas into said grinding zone, said classifier separating a coarse fraction from a fine fraction of material which has been ground in said pre and main grinding chambers, supp-lying said coarse fraction to said grinding zone and supp-lying said fine fraction out of said housing.
a housing defining a space and having a mantle face extending around said space;
a partition wall connected in said housing dividing said housing space into a pre-grinding chamber and a main grinding chamber and extending substantially transversely to said mantle face;
said housing including a portion defining a pregrin-ding portion having a cross-sectional area larger than said pre-grinding chamber, said pre-grinding portion being con-nected to said pre-grinding chamber;
material feed means connected to said housing and communicating with said pre-grinding portion for feeding a gas-tight plug of material to said pre-grinding portion;
a plurality of tangentially directed nozzles, uni-formly spaced around the mantle face and connected to said housing for supplying grinding gas under pressure to said pre-grinding portion of said housing;
a pair of concentric walls connected to said housing for separating said pre-grinding portion from said pre-grinding chamber, each of said concentric walls extending axially by at least one-half an overall height of said pre-grinding portion;
said housing having an outlet communicating with said main grinding chamber for discharging at least partial ly ground material from said main grinding chamber;
at least two laval nozzles extending through said partition wall extending toward a centerline of said main grinding chamber and forming an angle with each other, said laval nozzles communicating with said pre-grinding chamber and with said main grinding chamber and structured to pass material with grinding gas from said pre-grinding chamber to said main grinding chamber at supersonic speed, said main grinding chamber including a grinding zone adjacent an out-let of each of said two laval nozzlesat which material and grinding gas collide at supersonic speed, said grinding zone spaced from said outlet; and a classifier connected to said housing outlet and having a classifier outlet for discharging material and grin-ding gas into said grinding zone, said classifier separating a coarse fraction from a fine fraction of material which has been ground in said pre and main grinding chambers, supp-lying said coarse fraction to said grinding zone and supp-lying said fine fraction out of said housing.
2. A grinder according to claim 1, wherein said an-gle formed between said laval nozzles is from 60 to 180°.
3. A grinder according to claim 2, wherein said an-gle between said laval nozzles is 30 to 120°.
4. A grinder according to claim 1, wherein said mantle face around a portion of said housing space defining said main grinding chamber has a conical portion which redu-ces in diameter and terminates at said housing outlet.
5. A grinder according to claim 17 wherein said hou-sing has circular cross-sections, said pre-grinding portion being disposed radially outwardly of said pre-grinding cham-ber.
6. A grinder according to claim 5, wherein said hou-sing has a first cylindrical portion defining at least a portion of said pre-grinding and main grinding chambers, one of said concentric walls extending axially above said cy-lindrical portion of said housing, the other of said con-centric walls being disposed radially outwardly of said cy-lindrical portion and extending in an opposite direction in said pre-grinding portion.
7 A grinder according to claim 1, wherein said classifier is disposed in said pre-grinding chamber, a con-necting pipe connected between said housing outlet and said classifier for supplying material with grinding gas from said housing outlet into said classifier tangentially, and an outlet pipe connected near a center of said classifier and extending out of said housing for supplying the fine fraction of material out of said classifier.
8. A grinder according to claim 7, wherein said pre and main grinding chambers are circular, said classifier disposed near a center of said pre-grinding chamber.
9. A grinder according to claim 8, including a dist-ributor conduit surrounding said pre-grinding portion, said plurality of tangentially directed nozzles connected between said distributor conduit and said pre-grinding portion.
9.
9.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA000418370A CA1198401A (en) | 1982-12-22 | 1982-12-22 | Pressure-chamber grinder |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA000418370A CA1198401A (en) | 1982-12-22 | 1982-12-22 | Pressure-chamber grinder |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1198401A true CA1198401A (en) | 1985-12-24 |
Family
ID=4124207
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000418370A Expired CA1198401A (en) | 1982-12-22 | 1982-12-22 | Pressure-chamber grinder |
Country Status (1)
Country | Link |
---|---|
CA (1) | CA1198401A (en) |
-
1982
- 1982-12-22 CA CA000418370A patent/CA1198401A/en not_active Expired
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