CA1036349A - Fluid energy drying and grinding mill - Google Patents
Fluid energy drying and grinding millInfo
- Publication number
- CA1036349A CA1036349A CA205,844A CA205844A CA1036349A CA 1036349 A CA1036349 A CA 1036349A CA 205844 A CA205844 A CA 205844A CA 1036349 A CA1036349 A CA 1036349A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- passageway
- chamber
- grinding
- discharge nozzle
- 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
Links
- 239000012530 fluid Substances 0.000 title claims abstract description 27
- 238000000227 grinding Methods 0.000 title claims abstract description 27
- 238000001035 drying Methods 0.000 title claims abstract description 16
- 239000002002 slurry Substances 0.000 claims abstract description 35
- 239000007787 solid Substances 0.000 claims abstract description 15
- 230000002093 peripheral effect Effects 0.000 claims description 10
- 235000014676 Phragmites communis Nutrition 0.000 claims description 2
- 239000000049 pigment Substances 0.000 abstract description 3
- -1 e.g. Substances 0.000 abstract 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 9
- 239000002245 particle Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000002674 ointment Substances 0.000 description 2
- WWYNJERNGUHSAO-XUDSTZEESA-N (+)-Norgestrel Chemical compound O=C1CC[C@@H]2[C@H]3CC[C@](CC)([C@](CC4)(O)C#C)[C@@H]4[C@@H]3CCC2=C1 WWYNJERNGUHSAO-XUDSTZEESA-N 0.000 description 1
- ODPOAESBSUKMHD-UHFFFAOYSA-L 6,7-dihydrodipyrido[1,2-b:1',2'-e]pyrazine-5,8-diium;dibromide Chemical compound [Br-].[Br-].C1=CC=[N+]2CC[N+]3=CC=CC=C3C2=C1 ODPOAESBSUKMHD-UHFFFAOYSA-L 0.000 description 1
- 241000237074 Centris Species 0.000 description 1
- 239000005630 Diquat Substances 0.000 description 1
- 229910003074 TiCl4 Inorganic materials 0.000 description 1
- 240000004543 Vicia ervilia Species 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 238000010981 drying operation Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
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
- B02C21/00—Disintegrating plant with or without drying of the material
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Disintegrating Or Milling (AREA)
- Drying Of Solid Materials (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Crushing And Grinding (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A fluid energy mill of the confined vortex type is designed to permit the simultaneous drying and grind-ing of slurries of pulverulent solids, e.g., pigment slurries. The slurry is directed into a passageway leading to the grinding chamber in such a way as to be enveloped and atomized by a flow of gaseous drying fluid, e.g., high pressure steam, of at least sonic velocity.
The solids become at least partially dried before enter-ing the grinding chamber but with little or no tendency to adhere to the walls of the passageway leading thereto.
A fluid energy mill of the confined vortex type is designed to permit the simultaneous drying and grind-ing of slurries of pulverulent solids, e.g., pigment slurries. The slurry is directed into a passageway leading to the grinding chamber in such a way as to be enveloped and atomized by a flow of gaseous drying fluid, e.g., high pressure steam, of at least sonic velocity.
The solids become at least partially dried before enter-ing the grinding chamber but with little or no tendency to adhere to the walls of the passageway leading thereto.
Description
103634~9 BACKGROUND 0~ THE INV~NTION
Fluld energy mllls of the con~ined vortex type are well known and widely employed in certain industrle~
such as the plgment, co~metlc and plastic lndustries be-csuse o~ thelr efflciency ~nd economy ln the grinding of pulverulent ~olld~. A number Or early de6igns are de-scribed ln considerable detail in U.S. Patent 2,032,827.
Most such fluid energy mills are varlation~ on a ba~ic configuration of a generally clrcular chamber enclosed by a pair of axial walls and a peripheral wall, the axial length or helght of the chamber being ~ub-stantially les~ than the diameter. At the periphery Or the mill there is located at least one inlet for in~ectlng the gaseous grinding fluid which furnishes the energy for grinding the sollds, and one or more feed devices ~or lntroduclng the pulverulent solids to be ground. Pref-erably several uniformly spaced apart lnlets for gaseous grinding ~luld are provided around the circumference o~ the mlll and they are oriented generally tangentially to the chamber. An outlet coaxial to and ln direct communication with the grinding chamber ls provided ~or discharge o~ the ground ~ollds to a cyclone or bag rilter for collection.
Fluid energy mills of the foregoing type combine both grlnding and clas~ification wlthln a slngle chamber.
A~ the gaseous grinding fluld i~ fed tangentially into the perlphery of the chamber along with the solids to be ground vortex i8 created ~hereby the particies are swept along ln a splral path to be eventually discharged at the central outlet. By proper ~election of operatlng condltlons, such as rate And tangency Or fluid inJection, particles above , . . .
. .
; -2-,, a specific size can be kept within the mill until sufficient attrition occurs, whereas other particles are allowed to pass through.
Heretofore such fluid energy mills have not, however, been satisfactorily operable except with pulverulent solids which were in a relatively dry condition. Poor grinding and even clogging of passages could occur if excess liquid were present. This has been a disadvantage in certain areas where the treatment of liquid-laden solids such as slurries would be desirable. For example, in the case of TiO2 pigments produced by the vapor phase oxida-tion of TiCl4, the particles as formed are frequently collected as a water slurry. The utilization then of a fluid energy milling step, invariably needed to break up particle agglomerates, has meant that it would first be necessary to dry the particles, e.g., via a costly drying operation.
The desirability of a fluid energy mill permitting drying and grinding functions to be carried out simultaneously will be apparent.
SUMMARY OF THE INVENTION
The present invention relates to a fluid energy mill of the confined vortex type as described above but with a feed device that enables it to be used for the simultaneous drying and grinding of slurries of pulverulent solids. More particularly there is used a slurry feed device formed by walls defining a generally rectilinear passageway which opens into a peripheral region of the grinding chamber, ~03634~
a slurry supply condult havlng an lnlet remote .~rom the passageway and a dlscharge nozzle posltloned in the pas6ageway for dlrectlng slurry along the passageway .~ and toward the grinding cha~ber, the size of the dlscharge nozzle belng 8mall relatlve to the surroundlng pas~ageway to deflne an annular space therebetween, means for supplylng gaseouR drying fluid of at least ~onlc velocity to the annular space to thereby envelop and atomize within the passageway slurry emerging from the dlscharge nozzle, and means ~or controlllng the temperature of the dis-charge nozzle.
DETAILED DESCRIPTION OF THE DRAWINGS
The inYentlon will be further described with reference to the drawin~s, not to scale and with the same reference characters used to denote identical part~, wherein:
Flgure 1 shows a side elevatlonal view, partly in cross-~ectlon, of an apparatus of the inventlon, the - .
.. 20 slurry feed device being show.n generally as A, - Figure 2 is a horizon~al Yiew, also partly in cross-section, of the apparatus Or Flgure 1 taken normal ;: :
to the aX19 at the level of the inlet ~ets, - Flgure 3 illustrates ln greater detall the slurry ~` reed devlce A, the view being a horlzontal cross-sectlonal ~: . vlew, and . Figure 3a i8 a cross-sectlonal ~lew taken across .- 3a-3a' Or Figure 3.
In Fig. 1 and Fig. 2, 1 ls a header ror ga~eous 30 - gr~ndlng ~luid and enclrcles peripheral ~al} 2 o~ generall~
~4 r 103~349 clrcul~r grlndin~ ~.hamber 3. Inlets 4, o~ whlch only rour ~re ~ho~n, interconnect the he~der and the grlnding chamber.
Axlal walls 5 and 6 of the chamber may be relatlvoly parallel but in the preferred embodlment, a~ shown, come clo~er to one another a~ the ch~mber axi~ i8 approached.
Circular di~charge port 7 and exhau~t duct 8 are axlally located. Fluld from each inlet 4 enters the perlpheral wall 2 generally tangentially of the chamber, l.e., at an angle that is tangent to a circle about the center Or the chamber which has a radius smaller than the radius Or the chamber. A multipliclty of the~e inlets for gaseous gr~nding fluid is advantageously u~ed, twelve belng con-venient for a chamber of 27 inches diameter.
~ slurry feed device ~hown generally as A, and to be described more fully hereinQfter ln connection with ~igure 3, ~erve~ to introduce }iquid-laden solids, preferablY
a solids slurry such as a TiO2 pigment ~lurry ln water, to a peripheral region of the chamber through elongated pa~ago-way 10, the latter being aligned nearly tangentially to perlpheral wall 2 to facilitate flow of the solids into the chamber vortex. Passageway 10 preferably opens ~to the chamber directly through peripheral wall 2, as shown, but it may alternatively open into the chamber through upper . ~ axial wall 5 ln close proxlmity to peripheral wall 2. The cyllndrical discharge opening rormed by dlscharge port 7, ln con~unctlon with conical enclosure 9, ~orms a centri~ugal separator into which the ground product settle~ to be col-lected while the grindlng fluid ~lows out through e~haust duct ~.
Rererring no~ to Figure 3 and to the details o~
. .
, _~.
:~03~j3~
the slurry feed device A for introduclng ~nd drylng the 81urry, elone~ted pas8aeeway 10, throu~h whlch the ~ollds ultimately pass into the grinding chamber, ls formed by annular wall~ 21,22 which abut at flange~ 23,24, are held ! together by bolts 25, with an 0-ring gasket 26 in position as shown. An extension of wall 22 forms housing 27 which ie adapted to accommodate the entry of high velocity gaseou~
drying fluld, e.g., high pre~sure ~team suppl~ed vla pipe 28, ; which intersects passageway 10 at a rlght angle.
Communicating with pas~ageway 10 in axlal align-ment with the relatively wider upstream portlon thereof , . i8 a slurry ~upply conduit shown generally as 29 which i~
connected at its ~eed lnlet ~0 to a source of the ~lurry i to be dried and ground. Conduit 29 is maintained in posi-tlon against housing ?7 by means of bolts 33. 0-rings 35 are ln contact wlth sh1m plate 34 to-ase~st ~n preven~ing le~k~
Or gaseous drying fluld.
Conduit 29 extends into houslng 27 and ls con~er-gently tapered at its forward extremlty to form discharge nozzle 36. The latter is centered within the wider portion . ., of passageway 10 leaving a small annular space 37 between pas~ageway lip 38 and discharge nozzle 36 for flow Or gaseous drylng Muid so as to envelop the stream of slurry emerglng . .
rom the dlscharge nozzle and passing into the narrower por-- tlon of passageway 10.
By varying the thickness of shlm plate 34 the size Or annular space 37 is varied.
' As shown more clearly in Figure 3a, slurry condult ~ 29 ls composed of inner cylindrical element 41 and outer ; 30 cylindrical element 42, the two being welded at each end.
,, .
., .-~3~
Hence, essentlally fully along the leneth Or corldult 29 i~
channel 39 for flow o~ heat exchange fluid, e.g., cold water, therethrough. Elon~ated baffles 43 and 44 are welded to cylinder 41 and extend nearly the entire length of ch~nnel 39.
m u~ the heat exchange fluld will for the most part enter at threaded connectlon 45, traverse the length of conduit 29 through channel 39, return and finally exit at threaded con-nectlon 46. It i8 especially desirable that the portlon of condult 29 which is exposed to the high veloclty gaseous drying fluid from pipe 28 be able to have lts temperature appropriately controlled by the heat exchange fluid.
DESCRIPTION OF SPECIFIC EMBODIMENTS
.
Insofar as the grinding ~unction is concerned, the operatlon of the fluld energy mill of the inventlon follows that of ~lmllar devices of the prior art. In this respect reference ls made to the arorementioned U.S. Patent 2,032,827 to Andrews and additionally to U.S. Patent 3,462~o86 to Bertrand et al.
With respect to the improvement accordlng to the present invention) gaseous drying fluid, preferably steam, .
rlo~ing through pipe 28 at a relatlvely lo~ velocity and high pressure, undergoes a marked increase in velocity, to at least sonic velocity, as it emerges from what amounts to a converging-diverglng nozzle at annular space 37 and comes in conthct with slurry passing through discharge nozzle 36 at a relatlvely lo~ velocity. Mass transfer and heat transfer ln the reglon of the discharge nozzle are extremely rapid.
Deslrably, enough heat will be supplied by the gaseous . .
, . .
:
~r 103t;349 drylng rluld to permlt the temperature Or the resultlng mlx-ture to remain above saturation temperature. The pulverulent sollds will hence be at least surrace dry berore enterlng the grinding chamber where they are subJected to the actlon of a gaseous grlnding fluid, which like the gaseous drylng fluld ls also preferably steam.
The envelope of gaseous drylng fluid about the stream of slurry issuing from discharge nozzle 36 serves not only in the drying ~unctlon but also in preventing a buildup of solids along the wall~ of pa~æageway 10. Like-.
wlse, a flow of a cooling liquid such as chilled water through channel ~9 of slurry supply conduit 29 aids in pre- ~ :
venting premature dryine of the slurry on the inner wall~
of the conduit or on discharge nozzle ~6. It ls par-tlcularly important at start-up that the discharge nozzle temperature not become excess~vely high before the slurry ~low i8 commenced in order that solid~ do not baka out on the inner conduit wall.
While it is preferred to employ a multlplicity Or inlets 4 f~r gaseous grinding fluid,as shown in Figures : 1 and 2, it is also practical to omit them under certaln . circumstances. For example where the grinding runction is only of secondary importance as compared to the drying ~unction, the gaseous drying fluid supplied to chamber 3 vla passageway 10 can be adequate to serve a~ grlnding fluid : a~ well.
Whlle the present inventlon is partlcularly de-. ~crlbed wlth reference to the treatment of aqueou~ TiO2slurrie it will be apparent that it is also appllcable :~ 30 to u~e wlth var~ous other materi~ls as well.
~ .
- -~r 10;~;3~9 ; EXAMPLE
The materlal to be dried and ground ~s a slurry ln water Or uncoated rutile TiO2 partlcles having an average partlcle ~ize of about 0.22 mlcron. The solid~ content of the slurry is 64~ by weight and its feed rate 18 6100 pounds per hour.
The fluid energy mill is that descrlbed ln connection with the drawing~. The axial wall~ converge from a height of ~-~ ~ inch at the perlphery to 2-1t4 inch at the discharge port. The grlnding chamber is 27 ~nche~
in dlameter. There is a series of 12 tangential ring Jets a~ inlets for ~low of 518qF., and 150 psig steam at the rate o~ 3200 pound~ per hour into the grinding chamber.
The drying fluld is 800F, steam ~ed to a 2-7 inch lnternal diameter supply pipe at 450 pslg and at the rate Or 8000 pounds per hours. The annular clearance ;5 ~urrounding the discharge nozzle of the slurry supply con-~, duit ls 0.070 inch. ~he passageway is 1-7/8 inches in diameter at the narro~est portion ~ust beyond the dis-charge nozzle and expands to 2-7/8 inches in diameter; lts ~- length from the nozzle to the grinding chamber is 19-5/8 ', inches.
~ he tem~erature of the steam di~charged from the Brinding chamber is 338qF. The overall steam to pigmen~
r~tio is 7Ø
~he quality of the product i~ rated equivalent O
to the same TiO2 dried separately and ground in a con-- ventional m~nner. No pluggage o~ the slurry f~ed device i8 encountered throughout an extended run.
.. - .... .
: , , . ~ , .
_ 9 _ ,i .
,, " , . __ .' .,~ '
Fluld energy mllls of the con~ined vortex type are well known and widely employed in certain industrle~
such as the plgment, co~metlc and plastic lndustries be-csuse o~ thelr efflciency ~nd economy ln the grinding of pulverulent ~olld~. A number Or early de6igns are de-scribed ln considerable detail in U.S. Patent 2,032,827.
Most such fluid energy mills are varlation~ on a ba~ic configuration of a generally clrcular chamber enclosed by a pair of axial walls and a peripheral wall, the axial length or helght of the chamber being ~ub-stantially les~ than the diameter. At the periphery Or the mill there is located at least one inlet for in~ectlng the gaseous grinding fluid which furnishes the energy for grinding the sollds, and one or more feed devices ~or lntroduclng the pulverulent solids to be ground. Pref-erably several uniformly spaced apart lnlets for gaseous grinding ~luld are provided around the circumference o~ the mlll and they are oriented generally tangentially to the chamber. An outlet coaxial to and ln direct communication with the grinding chamber ls provided ~or discharge o~ the ground ~ollds to a cyclone or bag rilter for collection.
Fluid energy mills of the foregoing type combine both grlnding and clas~ification wlthln a slngle chamber.
A~ the gaseous grinding fluld i~ fed tangentially into the perlphery of the chamber along with the solids to be ground vortex i8 created ~hereby the particies are swept along ln a splral path to be eventually discharged at the central outlet. By proper ~election of operatlng condltlons, such as rate And tangency Or fluid inJection, particles above , . . .
. .
; -2-,, a specific size can be kept within the mill until sufficient attrition occurs, whereas other particles are allowed to pass through.
Heretofore such fluid energy mills have not, however, been satisfactorily operable except with pulverulent solids which were in a relatively dry condition. Poor grinding and even clogging of passages could occur if excess liquid were present. This has been a disadvantage in certain areas where the treatment of liquid-laden solids such as slurries would be desirable. For example, in the case of TiO2 pigments produced by the vapor phase oxida-tion of TiCl4, the particles as formed are frequently collected as a water slurry. The utilization then of a fluid energy milling step, invariably needed to break up particle agglomerates, has meant that it would first be necessary to dry the particles, e.g., via a costly drying operation.
The desirability of a fluid energy mill permitting drying and grinding functions to be carried out simultaneously will be apparent.
SUMMARY OF THE INVENTION
The present invention relates to a fluid energy mill of the confined vortex type as described above but with a feed device that enables it to be used for the simultaneous drying and grinding of slurries of pulverulent solids. More particularly there is used a slurry feed device formed by walls defining a generally rectilinear passageway which opens into a peripheral region of the grinding chamber, ~03634~
a slurry supply condult havlng an lnlet remote .~rom the passageway and a dlscharge nozzle posltloned in the pas6ageway for dlrectlng slurry along the passageway .~ and toward the grinding cha~ber, the size of the dlscharge nozzle belng 8mall relatlve to the surroundlng pas~ageway to deflne an annular space therebetween, means for supplylng gaseouR drying fluid of at least ~onlc velocity to the annular space to thereby envelop and atomize within the passageway slurry emerging from the dlscharge nozzle, and means ~or controlllng the temperature of the dis-charge nozzle.
DETAILED DESCRIPTION OF THE DRAWINGS
The inYentlon will be further described with reference to the drawin~s, not to scale and with the same reference characters used to denote identical part~, wherein:
Flgure 1 shows a side elevatlonal view, partly in cross-~ectlon, of an apparatus of the inventlon, the - .
.. 20 slurry feed device being show.n generally as A, - Figure 2 is a horizon~al Yiew, also partly in cross-section, of the apparatus Or Flgure 1 taken normal ;: :
to the aX19 at the level of the inlet ~ets, - Flgure 3 illustrates ln greater detall the slurry ~` reed devlce A, the view being a horlzontal cross-sectlonal ~: . vlew, and . Figure 3a i8 a cross-sectlonal ~lew taken across .- 3a-3a' Or Figure 3.
In Fig. 1 and Fig. 2, 1 ls a header ror ga~eous 30 - gr~ndlng ~luid and enclrcles peripheral ~al} 2 o~ generall~
~4 r 103~349 clrcul~r grlndin~ ~.hamber 3. Inlets 4, o~ whlch only rour ~re ~ho~n, interconnect the he~der and the grlnding chamber.
Axlal walls 5 and 6 of the chamber may be relatlvoly parallel but in the preferred embodlment, a~ shown, come clo~er to one another a~ the ch~mber axi~ i8 approached.
Circular di~charge port 7 and exhau~t duct 8 are axlally located. Fluld from each inlet 4 enters the perlpheral wall 2 generally tangentially of the chamber, l.e., at an angle that is tangent to a circle about the center Or the chamber which has a radius smaller than the radius Or the chamber. A multipliclty of the~e inlets for gaseous gr~nding fluid is advantageously u~ed, twelve belng con-venient for a chamber of 27 inches diameter.
~ slurry feed device ~hown generally as A, and to be described more fully hereinQfter ln connection with ~igure 3, ~erve~ to introduce }iquid-laden solids, preferablY
a solids slurry such as a TiO2 pigment ~lurry ln water, to a peripheral region of the chamber through elongated pa~ago-way 10, the latter being aligned nearly tangentially to perlpheral wall 2 to facilitate flow of the solids into the chamber vortex. Passageway 10 preferably opens ~to the chamber directly through peripheral wall 2, as shown, but it may alternatively open into the chamber through upper . ~ axial wall 5 ln close proxlmity to peripheral wall 2. The cyllndrical discharge opening rormed by dlscharge port 7, ln con~unctlon with conical enclosure 9, ~orms a centri~ugal separator into which the ground product settle~ to be col-lected while the grindlng fluid ~lows out through e~haust duct ~.
Rererring no~ to Figure 3 and to the details o~
. .
, _~.
:~03~j3~
the slurry feed device A for introduclng ~nd drylng the 81urry, elone~ted pas8aeeway 10, throu~h whlch the ~ollds ultimately pass into the grinding chamber, ls formed by annular wall~ 21,22 which abut at flange~ 23,24, are held ! together by bolts 25, with an 0-ring gasket 26 in position as shown. An extension of wall 22 forms housing 27 which ie adapted to accommodate the entry of high velocity gaseou~
drying fluld, e.g., high pre~sure ~team suppl~ed vla pipe 28, ; which intersects passageway 10 at a rlght angle.
Communicating with pas~ageway 10 in axlal align-ment with the relatively wider upstream portlon thereof , . i8 a slurry ~upply conduit shown generally as 29 which i~
connected at its ~eed lnlet ~0 to a source of the ~lurry i to be dried and ground. Conduit 29 is maintained in posi-tlon against housing ?7 by means of bolts 33. 0-rings 35 are ln contact wlth sh1m plate 34 to-ase~st ~n preven~ing le~k~
Or gaseous drying fluld.
Conduit 29 extends into houslng 27 and ls con~er-gently tapered at its forward extremlty to form discharge nozzle 36. The latter is centered within the wider portion . ., of passageway 10 leaving a small annular space 37 between pas~ageway lip 38 and discharge nozzle 36 for flow Or gaseous drylng Muid so as to envelop the stream of slurry emerglng . .
rom the dlscharge nozzle and passing into the narrower por-- tlon of passageway 10.
By varying the thickness of shlm plate 34 the size Or annular space 37 is varied.
' As shown more clearly in Figure 3a, slurry condult ~ 29 ls composed of inner cylindrical element 41 and outer ; 30 cylindrical element 42, the two being welded at each end.
,, .
., .-~3~
Hence, essentlally fully along the leneth Or corldult 29 i~
channel 39 for flow o~ heat exchange fluid, e.g., cold water, therethrough. Elon~ated baffles 43 and 44 are welded to cylinder 41 and extend nearly the entire length of ch~nnel 39.
m u~ the heat exchange fluld will for the most part enter at threaded connectlon 45, traverse the length of conduit 29 through channel 39, return and finally exit at threaded con-nectlon 46. It i8 especially desirable that the portlon of condult 29 which is exposed to the high veloclty gaseous drying fluid from pipe 28 be able to have lts temperature appropriately controlled by the heat exchange fluid.
DESCRIPTION OF SPECIFIC EMBODIMENTS
.
Insofar as the grinding ~unction is concerned, the operatlon of the fluld energy mill of the inventlon follows that of ~lmllar devices of the prior art. In this respect reference ls made to the arorementioned U.S. Patent 2,032,827 to Andrews and additionally to U.S. Patent 3,462~o86 to Bertrand et al.
With respect to the improvement accordlng to the present invention) gaseous drying fluid, preferably steam, .
rlo~ing through pipe 28 at a relatlvely lo~ velocity and high pressure, undergoes a marked increase in velocity, to at least sonic velocity, as it emerges from what amounts to a converging-diverglng nozzle at annular space 37 and comes in conthct with slurry passing through discharge nozzle 36 at a relatlvely lo~ velocity. Mass transfer and heat transfer ln the reglon of the discharge nozzle are extremely rapid.
Deslrably, enough heat will be supplied by the gaseous . .
, . .
:
~r 103t;349 drylng rluld to permlt the temperature Or the resultlng mlx-ture to remain above saturation temperature. The pulverulent sollds will hence be at least surrace dry berore enterlng the grinding chamber where they are subJected to the actlon of a gaseous grlnding fluid, which like the gaseous drylng fluld ls also preferably steam.
The envelope of gaseous drylng fluid about the stream of slurry issuing from discharge nozzle 36 serves not only in the drying ~unctlon but also in preventing a buildup of solids along the wall~ of pa~æageway 10. Like-.
wlse, a flow of a cooling liquid such as chilled water through channel ~9 of slurry supply conduit 29 aids in pre- ~ :
venting premature dryine of the slurry on the inner wall~
of the conduit or on discharge nozzle ~6. It ls par-tlcularly important at start-up that the discharge nozzle temperature not become excess~vely high before the slurry ~low i8 commenced in order that solid~ do not baka out on the inner conduit wall.
While it is preferred to employ a multlplicity Or inlets 4 f~r gaseous grinding fluid,as shown in Figures : 1 and 2, it is also practical to omit them under certaln . circumstances. For example where the grinding runction is only of secondary importance as compared to the drying ~unction, the gaseous drying fluid supplied to chamber 3 vla passageway 10 can be adequate to serve a~ grlnding fluid : a~ well.
Whlle the present inventlon is partlcularly de-. ~crlbed wlth reference to the treatment of aqueou~ TiO2slurrie it will be apparent that it is also appllcable :~ 30 to u~e wlth var~ous other materi~ls as well.
~ .
- -~r 10;~;3~9 ; EXAMPLE
The materlal to be dried and ground ~s a slurry ln water Or uncoated rutile TiO2 partlcles having an average partlcle ~ize of about 0.22 mlcron. The solid~ content of the slurry is 64~ by weight and its feed rate 18 6100 pounds per hour.
The fluid energy mill is that descrlbed ln connection with the drawing~. The axial wall~ converge from a height of ~-~ ~ inch at the perlphery to 2-1t4 inch at the discharge port. The grlnding chamber is 27 ~nche~
in dlameter. There is a series of 12 tangential ring Jets a~ inlets for ~low of 518qF., and 150 psig steam at the rate o~ 3200 pound~ per hour into the grinding chamber.
The drying fluld is 800F, steam ~ed to a 2-7 inch lnternal diameter supply pipe at 450 pslg and at the rate Or 8000 pounds per hours. The annular clearance ;5 ~urrounding the discharge nozzle of the slurry supply con-~, duit ls 0.070 inch. ~he passageway is 1-7/8 inches in diameter at the narro~est portion ~ust beyond the dis-charge nozzle and expands to 2-7/8 inches in diameter; lts ~- length from the nozzle to the grinding chamber is 19-5/8 ', inches.
~ he tem~erature of the steam di~charged from the Brinding chamber is 338qF. The overall steam to pigmen~
r~tio is 7Ø
~he quality of the product i~ rated equivalent O
to the same TiO2 dried separately and ground in a con-- ventional m~nner. No pluggage o~ the slurry f~ed device i8 encountered throughout an extended run.
.. - .... .
: , , . ~ , .
_ 9 _ ,i .
,, " , . __ .' .,~ '
Claims (5)
1. A fluid energy mill of the confined vortex type for drying and grinding a slurry of pulverulent solids, said mill comprising:
a generally circular grinding chamber defined by a pair of opposing axial walls and a peripheral wall, a slurry feed device formed by walls defining a generally rectilinear passageway which opens into a peripheral region of said chamber, a slurry supply conduit having an inlet remote from said passageway and a discharge nozzle positioned in said passageway for directing slurry along the passageway and toward said chamber, the size of discharge nozzle being small relative to the surrounding passageway to define an annular space therebetween, means for supplying gaseous drying fluid of at least sonic velocity to said annular space to thereby envelop and atomize within the passageway slurry emerging from said discharge nozzle, means for controlling the temperature of said discharge nozzle, and discharge means for withdrawing pulverulent solids and gaseous grinding fluid along the axis of the chamber.
a generally circular grinding chamber defined by a pair of opposing axial walls and a peripheral wall, a slurry feed device formed by walls defining a generally rectilinear passageway which opens into a peripheral region of said chamber, a slurry supply conduit having an inlet remote from said passageway and a discharge nozzle positioned in said passageway for directing slurry along the passageway and toward said chamber, the size of discharge nozzle being small relative to the surrounding passageway to define an annular space therebetween, means for supplying gaseous drying fluid of at least sonic velocity to said annular space to thereby envelop and atomize within the passageway slurry emerging from said discharge nozzle, means for controlling the temperature of said discharge nozzle, and discharge means for withdrawing pulverulent solids and gaseous grinding fluid along the axis of the chamber.
2. Mill according to Claim 1 wherein the passage-way of said slurry feed device opens into the peripheral wall of said grinding chamber.
3. Mill according to Claim 1 wherein the passage-way of said slurry reed device opens generally tangentially into the peripheral wall of said grinding chamber.
4. Mill according to Claim 1 wherein the means for controlling the temperature of the discharge nozzle comprises a channel inside the walls of the slurry supply conduit for flow of a heat exchange medium therethrough.
5. Mill according to Claim 1 wherein the dis-charge nozzle forms a converging-diverging nozzle with the adjacent portion the passageway.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US00384355A US3840188A (en) | 1973-07-31 | 1973-07-31 | Fluid energy drying and grinding mill |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036349A true CA1036349A (en) | 1978-08-15 |
Family
ID=23517004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA205,844A Expired CA1036349A (en) | 1973-07-31 | 1974-07-29 | Fluid energy drying and grinding mill |
Country Status (16)
| Country | Link |
|---|---|
| US (1) | US3840188A (en) |
| JP (1) | JPS5640634B2 (en) |
| AR (1) | AR204328A1 (en) |
| BE (1) | BE818271A (en) |
| BR (1) | BR7406269D0 (en) |
| CA (1) | CA1036349A (en) |
| DE (1) | DE2435181A1 (en) |
| DK (1) | DK139773B (en) |
| ES (1) | ES428778A1 (en) |
| FI (1) | FI59345C (en) |
| FR (1) | FR2239290B1 (en) |
| GB (1) | GB1411369A (en) |
| IE (1) | IE39907B1 (en) |
| IT (1) | IT1027536B (en) |
| NL (1) | NL7410235A (en) |
| ZA (1) | ZA744817B (en) |
Families Citing this family (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2243795B1 (en) * | 1973-09-14 | 1978-06-16 | Huels Chemische Werke Ag | |
| US4298229A (en) * | 1979-04-11 | 1981-11-03 | Alli Sebastian J D | Process for dry mining phosphate ore utilizing a supersonic gas |
| GB2077125B (en) * | 1980-05-16 | 1984-10-24 | Draiswerke Gmbh | Apparatus for feeding flowable solids and liquids to treatment machines |
| US4565328A (en) * | 1983-08-08 | 1986-01-21 | Combustion Engineering, Inc. | Sand reclamation system with thermal pipe reclaimer apparatus |
| US4610395A (en) * | 1984-02-27 | 1986-09-09 | Ford James A | Process for producing particulate pigment having improved tinctorial characteristics |
| GB8628586D0 (en) * | 1986-11-29 | 1987-01-07 | Tioxide Group Plc | Mill |
| GB8720904D0 (en) * | 1987-09-05 | 1987-10-14 | Tioxide Group Plc | Mill |
| US5281379A (en) * | 1989-04-05 | 1994-01-25 | Kanebo, Ltd. | Processes for manufacturing thermoplastic resin compositions |
| GB8913819D0 (en) * | 1989-06-15 | 1989-08-02 | Tioxide Group Plc | Shaped articles |
| US5099619A (en) * | 1989-08-07 | 1992-03-31 | Rose Leo J | Pneumatic particulate blaster |
| US5542613A (en) * | 1992-12-10 | 1996-08-06 | Nied; Roland | Process for impact crushing of solid particles |
| US5637344A (en) * | 1995-10-20 | 1997-06-10 | Hershey Foods Corporation | Chocolate flavored hard candy |
| JPH1094758A (en) * | 1996-09-25 | 1998-04-14 | Minolta Co Ltd | Air classifier and production of electrophotographic toner using the same |
| RU2170617C2 (en) * | 1999-07-06 | 2001-07-20 | Шокин Владимир Васильевич | Versatile counterflow jet unit for high-temperature processing of raw material |
| US7422167B2 (en) * | 2002-04-11 | 2008-09-09 | Sturtevant, Inc. | Fluid-energy mill |
| US20050132893A1 (en) * | 2003-12-17 | 2005-06-23 | Kraft Foods Holdings, Inc. | Process for single-stage heat treatment and grinding of coffee beans |
| US20060029703A1 (en) * | 2004-08-06 | 2006-02-09 | Kraft Foods Holdings, Inc. | Process for single-stage heat treatment and grinding of mustard bran, and product and its uses |
| US20060040027A1 (en) * | 2004-08-17 | 2006-02-23 | Kraft Foods Holdings, Inc. | Process for manufacture of grated cheese and uses thereof |
| US7445806B2 (en) * | 2004-09-02 | 2008-11-04 | Kraft Foods Global Brands Llc | Process for selective grinding and recovery of dual-density foods |
| US20060083834A1 (en) * | 2004-10-14 | 2006-04-20 | Kraft Foods Holdings, Inc. | Process for granulation of wet processed foods and use thereof |
| US20060088634A1 (en) * | 2004-10-25 | 2006-04-27 | Kraft Foods Holdings, Inc. | Process for granulation of low-moisture processed foods and use thereof |
| US20060286232A1 (en) * | 2005-06-15 | 2006-12-21 | Kraft Foods Holdings, Inc. | Process for granulation of low-moisture, high-lipid content processed foods and re-use thereof |
| US20060286230A1 (en) * | 2005-06-15 | 2006-12-21 | Kraft Foods Holdings, Inc. | Process for packing separation and granulation of processed food content thereof, and products and uses thereof |
| US20060286246A1 (en) * | 2005-06-16 | 2006-12-21 | Kraft Foods Holdings, Inc. | Preparation of bakery mixes |
| US20060286269A1 (en) * | 2005-06-16 | 2006-12-21 | Kraft Foods Holdings, Inc. | Process for granulation of edible seeds |
| US7465859B2 (en) | 2006-06-01 | 2008-12-16 | Fender Musical Instruments Corporation | Headblock and fingerboard support |
| GB2482032B (en) | 2010-07-16 | 2013-04-10 | Kraft Foods R & D Inc | Coffee products and related processes |
| WO2024184679A1 (en) * | 2023-03-08 | 2024-09-12 | Areka Patents Inc | Jet-milling apparatus and method for jet-milling |
| CN116174187B (en) * | 2023-04-27 | 2023-06-30 | 厦门威圣邦流体科技有限公司 | Atomizing spraying device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE24314C (en) * | gebrüder zwanger in Tübingen | Combined baking, drying and cooking oven | ||
| US2032827A (en) * | 1933-11-21 | 1936-03-03 | Internat Pulverizing Corp | Method of and apparatus for providing material in finely divided form |
| US3317145A (en) * | 1964-01-02 | 1967-05-02 | Fluid Energy Proc & Equipment | Method and means for pulverizing and drying solids |
| US3462086A (en) * | 1966-07-01 | 1969-08-19 | Du Pont | Fluid energy milling process |
-
1973
- 1973-07-31 US US00384355A patent/US3840188A/en not_active Expired - Lifetime
-
1974
- 1974-01-01 AR AR254949A patent/AR204328A1/en active
- 1974-06-28 FI FI2003/74A patent/FI59345C/en active
- 1974-07-20 ES ES428778A patent/ES428778A1/en not_active Expired
- 1974-07-22 DE DE2435181A patent/DE2435181A1/en active Granted
- 1974-07-29 ZA ZA00744817A patent/ZA744817B/en unknown
- 1974-07-29 CA CA205,844A patent/CA1036349A/en not_active Expired
- 1974-07-30 FR FR7426382A patent/FR2239290B1/fr not_active Expired
- 1974-07-30 DK DK406574AA patent/DK139773B/en unknown
- 1974-07-30 NL NL7410235A patent/NL7410235A/en not_active Application Discontinuation
- 1974-07-30 JP JP8666174A patent/JPS5640634B2/ja not_active Expired
- 1974-07-30 BE BE147102A patent/BE818271A/en not_active IP Right Cessation
- 1974-07-30 BR BR6269/74A patent/BR7406269D0/en unknown
- 1974-07-30 IE IE1617/74A patent/IE39907B1/en unknown
- 1974-07-31 GB GB3384274A patent/GB1411369A/en not_active Expired
- 1974-07-31 IT IT25817/74A patent/IT1027536B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| NL7410235A (en) | 1975-02-04 |
| AU7177674A (en) | 1976-01-29 |
| AR204328A1 (en) | 1975-12-22 |
| FI59345C (en) | 1981-08-10 |
| BE818271A (en) | 1975-01-30 |
| IE39907B1 (en) | 1979-01-31 |
| DK139773C (en) | 1979-09-24 |
| FR2239290A1 (en) | 1975-02-28 |
| IT1027536B (en) | 1978-12-20 |
| GB1411369A (en) | 1975-10-22 |
| DK406574A (en) | 1975-03-10 |
| DE2435181A1 (en) | 1975-02-13 |
| DE2435181C2 (en) | 1988-04-21 |
| BR7406269D0 (en) | 1975-04-22 |
| FI59345B (en) | 1981-04-30 |
| IE39907L (en) | 1975-01-31 |
| US3840188A (en) | 1974-10-08 |
| ES428778A1 (en) | 1976-12-01 |
| FI200374A7 (en) | 1975-02-01 |
| JPS5043556A (en) | 1975-04-19 |
| DK139773B (en) | 1979-04-17 |
| ZA744817B (en) | 1975-08-27 |
| FR2239290B1 (en) | 1978-01-20 |
| JPS5640634B2 (en) | 1981-09-22 |
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