Title: Method of using a small scale mill
Abstract: A small-scale or micro media-mill and a method of milling materials or products, especially pharmaceutical products, use a dispersion containing attrition milling media and the product to be milled. The milling media can be polymeric, formed of polystyrene or cross-linked polystyrene, having a nominal diameter of no greater than 500 microns. Other sizes include 200 microns and 50 microns and a mixture of these sizes. The mill has a relatively small vessel having an opening, an agitator, a coupling and a motor. The agitator can have a rotor and a shaft extending therefrom. The rotor can be cylindrical or have other configurations, and can have tapered end surfaces. The coupling can close the vessel opening, or attaching the coupling to the motor can close the opening. The coupling has an opening through which the rotor shaft extends into the motor. A sealing mechanism, such as a mechanical or lip seals the shaft while permitting the rotor shaft to rotate. The vessel can contain one or more ports for circulating the dispersion, where milling can be made in batches or recirculated through the milling chamber. The media can be retained in the vessel or recirculated along with the process fluid. The rotor is dimensioned so that its outer periphery is spaced with a small gap from an inner surface of the vessel. The vessel also can have a way of cooling the dispersion.
Patent Number: 6,991,191 Issued on 01/31/2006 to Reed, et al.
| Inventors:
|
Reed; Robert Gary (Birdsboro, PA);
Czekai; David A. (Spring City, PA);
Bosch; Henry William (Bryn Mawr, PA);
Ryde; Niels-Peter Moesgaard (Malvern, PA)
|
| Assignee:
|
Elan Pharma International, Limited (Dublin, IE)
|
| Appl. No.:
|
833045 |
| Filed:
|
April 28, 2004 |
| Current U.S. Class: |
241/21; 424/489 |
| Current Intern'l Class: |
B02C 17/16 (20060101) |
| Field of Search: |
241/21,23,172
424/489
|
References Cited [Referenced By]
U.S. Patent Documents
| 4848676 | Jul., 1989 | Stehr.
| |
| 5133506 | Jul., 1992 | Bogen.
| |
| 5145684 | Sep., 1992 | Liversidge et al.
| |
| 5183215 | Feb., 1993 | Getzmann.
| |
| 5464163 | Nov., 1995 | Zoz.
| |
| 5518187 | May., 1996 | Bruno et al.
| |
| 5593097 | Jan., 1997 | Corbin.
| |
| 5718388 | Feb., 1998 | Czekai et al.
| |
| 5797550 | Aug., 1998 | Woodall et al.
| |
| 5862999 | Jan., 1999 | Czekai et al.
| |
| Foreign Patent Documents |
| 0483808 | May., 1992 | EP.
| |
| 0686428 | Dec., 1995 | EP.
| |
Other References
PCT International Search Report based on Appl. No. PCT/US00/014705.
Reinsch et al., "Energy Consumption for Wet Grinding in Stirred Mills," Aufbereitungs-Technik,
38(1997) 3, pp. 152-160.
The et al., "Autogenous Grinding of SIC in Stirred Mills with- out and with Grinding
Aids, Part 1," Aufbereitungs-Technik, 33(1992) 10, pp. 541-549.
Joost et al., "Feinstzerkleinerung in Rührwerkmühien," Das Jehrbuch
der Keramik, Reh, H., Bauverlag, Walluf, 1995, pp. 23-38.
Stadler et al., "Nassmahlung in Rührwerksmühien," Chem.-ing.-Tech.,
82(1990) 11, pp. 907-915.
Kwade et al., "Motion and Stress intensity of grinding beads in a stirred media
mill. Part 2: Stress intensity and its effect on comminution," Powder Technology,
86(1996), pp. 69-76.
|
Primary Examiner: Rosenbaum; Mark
Attorney, Agent or Firm: Foley & Lardner LLP
Parent Case Text
RELATED APPLICATIONS
This application is a continuation of application Ser. No. 10/037,566, filed
on Oct. 19, 2001, now U.S. Pat. No. 6,745,962, which is a divisional of application
Ser. No. 09/583,893, filed on May 31, 2000, now U.S. Pat. No. 6,431,478, which
is based on Provisional Application No. 60/137,142, filed on Jun. 1, 1999, the
disclosures of which are specifically incorporated by reference.
Claims
We claim:
1. A method of milling a pharmaceutical product comprising:
(a) providing a dispersion containing the product to be milled and attrition
milling media, wherein the attrition milling media has a mean particle size of
less than about 1000 microns;
(b) inserting the dispersion into a vessel;
(c) providing an agitator and a coupling that closes the vessel, the coupling
having an opening through which a portion of the agitator extends, the agitator
comprising a rotor and a shaft extending therefrom, wherein the rotor is dimensioned
so that an outer periphery is no greater than 3 mm away from an inner surface of
the wall of the vessel;
(d) inserting the agitator into the vessel and sealingly closing the coupling,
wherein the vessel is filled so that the dispersion eliminates substantially all
of the air in the vessel when the agitator is fully inserted into the vessel; and
(e) rotating the agitator for a predetermined period,
wherein the resulting milled pharmaceutical product has a submicron mean particle size.
2. The method of claim 1, wherein the pharmaceutical product is milled in the
presence of at least one surface modifier.
3. The method of claim 2, wherein the at least one surface modifier is selected
from the group consisting of gelatin, casein, lecithin, gum acacia, cholesterol,
tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glyceryl monostearate,
cetostearl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene
alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan
fatty acid esters, polyethylene glycols, polyoxyethylene stearates, colloidol silicon
dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, carboxymethylcellulose
sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethycellulose
phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine,
polyvinyl alcohol, polyvinylpyrrolidone, block copolymers of ethylene oxide and
propylene oxide, a tetrafunctional block copolymer derived from sequential addition
of ethylene oxide and propylene oxide to ethylenediamine, dextran, a dioctyl ester
of sodium sulfosuccinic acid, a sodium lauryl sulfate, and an alkyl aryl polyether sulfonate.
4. The method of claim 2, wherein the ratio of the distance between the outer
periphery of the rotor and the inner surface of the wall to the attrition milling
media nominal size is about 6 to about 1.
5. The method of claim 2, wherein the attrition media has a mean particle size
selected from the group consisting of: (a) less than about 500 microns; (b) less
than about 300 microns; (c) less than about 250 microns; (d) less than about 200
microns; (e) less than about 100 microns; (f) less than about 75 microns; (g) less
than about 50 microns, (h) less than about 25 microns; (i) less than about 5 microns;
and (j) a mixture thereof.
6. The method of claim 2, wherein the attrition media is selected from the group
consisting of polymeric, zirconium oxide, zirconium silicate, glass, stainless
steel, titania, alumina, and 95% ZrO stabilized with yttrium.
7. The method of claim 2, wherein the working volume of the vessel is about 12
mL to about 33 mL.
8. The method of claim 2, wherein the volume of the dispersion is about 5 ml
to about 23 mL.
9. The method of claim 2, wherein the volume of the dispersion is less than about
10 mL.
10. The method of claim 2, wherein the method further comprises maintaining substantially
uniform shear between the rotor and the and the cylindrical vessel.
11. The method of claim 2, wherein at the completion of the rotation period,
the pharmaceutical product has an average particle size selected from the group
consisting of less than about 500 nm, less than about 400 nm, less than about 300
nm, and less than about 100 nm.
12. The method of claim 11, wherein at least 90% of the milled pharmaceutical
product particles have a size less than that selected from the group consisting
of less than about 500 nm, less than about 400 nm, less than about 300 nm, and
less than about 100 nm.
13. The method of claim 11, wherein at least 95% of the milled pharmaceutical
product particles have a size less than that selected from the group consisting
of less than about 500 nm, less than about 400 nm, less than about 300 nm, and
less than about 100 nm.
14. The method of claim 11, wherein at least 99% of the milled pharmaceutical
product particles have a size less than that selected from the group consisting
of less than about 500 nm, less than about 400 nm, less than about 300 nm, and
less than about 100 nm.
15. The method of claim 2, wherein the dispersion is recirculated through the
vessel during rotation of the agitator.
16. The method of claim 2, wherein the pharmaceutical product is a heat sensitive product.
17. The method of claim 2, wherein the pharmaceutical product is selected from
the group consisting of analgesics, anti-inflammatory agents, anthelmintics, anti-arrhythmic
agents, antibiotics, anticoagulants, antidepressants, antidiabetic agents, antiepileptics,
antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial
agents, antineoplastic agents, immunosuppressants, antithyroid agents, antiviral
agents, anxiolytic sedatives, astringents, beta-adrenoceptor blocking agents, blood
products, blood substitutes, cardiac inotropic agents, contrast media, corticosteroids,
cough suppressants, diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics,
haemostatics, immunological agents, lipid regulating agents, muscle relaxants,
parasympathomimetics, parathyroid calcitonin, parathyroid biphosphonates, prostaglandins,
radio-pharmaceuticals, sex hormones, anti-allergic agents, stimulants, anoretics,
sympathomimetics, thyroid agents, vasodilators, and xanthines.
18. The method of claim 2, wherein the product is an NSAID.
19. The method of claim 18, wherein the NSAID is selected from the group consisting
of nabumetone, tiaramide, proquazone, bufexamac, flumizole, epirazole, tinoridine,
timegadine, dapsone, aspirin, diclofenac, alclofenac, fenclofenac, etodolac, indomethacin,
sulindac, tolmetin, fentiazac, tilomisole, carprofen, fenbufen, flurbiprofen, ketoprofen,
oxaprozin, suprofen, tiaprofenic acid, ibuprofen, naproxen, fenoprofen, indoprofen,
pirprofen, flufenamic, mefenamic, meclofenamic, niflumic, oxyphenbutazone, phenylbutazone,
apazone, feprazone, piroxicam, sudoxicam, isoxicam, and tenoxicam.
20. The method of claim 2, wherein the product is an anticancer agent.
21. The method of claim 20, wherein the anticancer agent is selected from the
group consisting of alkylating agents, antimetabolites, natural products, hormones,
and antagonists.
22. The method of claim 21, wherein the anticancer agent is selected from the
group consisting of: (1) alkylating agents having the bis-(2-chloroethyl)-amine
group; (2) alkylating agents having a substituted aziridine group; (3) alkylating
agents of the alkyl sulfonate type; (4) alkylating N-alkyl-N-nitrosourea derivatives;
(5) alkylating agents of the mitobronitole type; (6) alkylating agents of the dacarbazine
type; and (7) alkylating agents of the procarbazine type.
23. The method of claim 22, wherein the anticancer agent is selected from the
group consisting of chlormethine, chlorambucile, melphalan, uramustine, mannomustine,
extramustinephoshate, mechlore-thaminoxide, cyclophosphamide, ifosfamide, trifosfamide,
tretamine, thiotepa, triaziquone, mitomycine, busulfan, piposulfan, piposulfam,
carmustine, lomustine, semustine, streptozotocine.
24. The method of claim 21, wherein the anticancer agent is selected from the
group consisting of: (1) folic acid analogs; (2) pyrimidine analogs; and (3) purine derivatives.
25. The method of claim 24, wherein the anticancer agent is selected from the
group consisting of methotrexate, fluorouracil, floxuridine, tegafur, cytarabine,
idoxuridine, flucytosine, mercaptopurine, thioguanine, azathioprine, tiamiprine,
vidarabine, pentostatin, and puromycine.
26. The method of claim 21, wherein the anticancer agent is selected from the
group consisting of vinca alkaloids, epipodophylotoxins, antibiotics, enzymes,
biological response modifiers, camptothecin, taxol, and retinoids.
27. The method of claim 26, wherein the anticancer agent is selected from the
group consisting of vinblastine, vincristine, etoposide, teniposide, adriamycine,
daunomycine, doctinomycin, daunorubicin, doxorubicin, mithramycin, bleomycin, mitomycin,
L-asparaginase, alpha-interferon and retinoic acid.
28. The method of claim 21, wherein the anticancer agent is selected from the
group consisting of adrenocorticosteroids, progestins, estrogens, antiestrogens,
androgens, antiandrogens, and gonadotropin-releasing hormone analogs.
29. The method of claim 28, wherein the anticancer agent is selected from the
group consisting of prednisone, hydroxyprogesterone caproate, medroxyprogesterone
acetate, megestrol acetate, diethylstilbestrol, ethinyl estradiol, tamoxifen, testosterone
propionate, fluoxymesterone, flutamide, and leuprolide.
30. The method of claim 21, wherein the anticancer agent is selected from the
group consisting of radiosensitizers, platinum coordination complexes, anthracenediones,
substituted ureas, adrenocortical suppressants, and an immunosuppressive drug.
31. A method of milling a human or animal ingestable product comprising:
(a) providing a dispersion containing the product to be milled and attrition
milling media, wherein the attrition milling media has a mean particle size of
less than about 1000 microns;
(b) inserting the dispersion into a vessel;
(c) providing an agitator and a coupling that closes the vessel, the coupling
having an opening through which a portion of the agitator extends, the agitator
comprising a rotor and a shaft extending therefrom, wherein the rotor is dimensioned
so that an outer periphery is no greater than 3 mm away from an inner surface of
the vessel wall;
(d) inserting the agitator into the vessel and sealingly closing the coupling,
wherein the vessel is filled so that the dispersion eliminates substantially all
of the air in the vessel when the agitator is fully inserted into the vessel; and
(e) rotating the agitator for a predetermined period,
wherein the resulting human or animal ingestable product has a submicron mean
particle size.
32. The method of claim 31, wherein the human or animal ingestable product is
milled in the presence of at least one surface modifier.
33. The method of claim 32, wherein the at least one surface modifier is selected
from the group consisting of gelatin, casein, lecithin, gum acacia, cholesterol,
tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glyceryl monostearate,
cetostearl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene
alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan
fatty acid esters, polyethylene glycols, polyoxyethylene stearates, colloidol silicon
dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, carboxymethylcellulose
sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethycellulose
phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine,
polyvinyl alcohol, polyvinylpyrrolidone, block copolymers of ethylene oxide and
propylene oxide, a tetrafunctional block copolymer derived from sequential addition
of ethylene oxide and propylene oxide to ethylenediamine, dextran, a dioctyl ester
of sodium sulfosuccinic acid, a sodium lauryl sulfate, and an alkyl aryl polyether sulfonate.
34. The method of claim 32, wherein the ratio of the distance between the outer
periphery of the rotor and the inner surface of the wall to the attrition milling
media nominal size is about 6 to about 1.
35. The method of claim 32, wherein the attrition media has a mean particle size
selected from the group consisting of: (a) less than about 500 microns; (b) less
than about 300 microns; (c) less than about 250 microns; (d) less than about 200
microns; (e) less than about 100 microns; (f) less than about 75 microns; (g) less
than about 50 microns, (h) less than about 25 microns; (i) less than about 5 microns;
and (j) a mixture thereof.
36. The method of claim 32, wherein the attrition media is selected from the
group consisting of polymeric, zirconium oxide, zirconium silicate, glass, stainless
steel, titania, alumina, and 95% ZrO stabilized with yttrium.
37. The method of claim 32, wherein the working volume of the vessel is about
12 mL to about 33 mL.
38. The method of claim 32, wherein the volume of the dispersion is about 5 ml
to about 23 mL.
39. The method of claim 32, wherein the volume of the dispersion is less than
about 10 mL.
40. The method of claim 32, wherein the method further comprises maintaining
substantially uniform shear between the rotor and the and the vessel.
41. The method of claim 32, wherein at the completion of the rotation period,
the human or animal ingestable product has an average particle size selected from
the group consisting of less than about 500 nm, less than about 400 nm, less than
about 300 nm, and less than about 100 nm.
42. The method of claim 41, wherein at least 90% of the milled human or animal
ingestable product particles have a size less than that selected from the group
consisting of less than about 500 nm, less than about 400 nm, less than about 300
nm, and less than about 100 nm.
43. The method of claim 41, wherein at least 95% of the milled human or animal
ingestable product particles have a size less than that selected from the group
consisting of less than about 500 nm, less than about 400 nm, less than about 300
nm, and less than about 100 nm.
44. The method of claim 41, wherein at least 99% of the milled human or animal
ingestable product particles have a size less than that selected from the group
consisting of less than about 500 nm, less than about 400 nm, less than about 300
nm, and less than about 100 nm.
45. The method of claim 32, wherein the dispersion is recirculated through the
vessel during rotation of the agitator.
46. A method of milling a cosmetic product comprising:
(a) providing a dispersion containing the product to be milled and attrition
milling media, wherein the attrition milling media has a mean particle size of
less than about 1000 microns
(b) inserting the dispersion into a vessel;
(c) providing an agitator and a coupling that closes the vessel, the coupling
having an opening through which a portion of the agitator extends, the agitator
comprising a rotor and a shaft extending therefrom, wherein the rotor is dimensioned
so that an outer periphery is no greater than 3 mm away from an inner surface of
the vessel wall;
(d) inserting the agitator into the vessel and sealingly closing the coupling,
wherein the vessel is filled so that the dispersion eliminates substantially all
of the air in the vessel when the agitator is fully inserted into the vessel; and
(e) rotating the agitator for a predetermined period,
wherein the resulting cosmetic product has a submicron mean particle size.
47. The method of claim 46, wherein the cosmetic product is milled in the presence
of at least one surface modifier.
48. The method of claim 47, wherein the at least one surface modifier is selected
from the group consisting of gelatin, casein, lecithin, gum acacia, cholesterol,
tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glyceryl monostearate,
cetostearl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene
alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan
fatty acid esters, polyethylene glycols, polyoxyethylene stearates, colloidol silicon
dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, carboxymethylcellulose
sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethycellulose
phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine,
polyvinyl alcohol, polyvinylpyrrolidone, block copolymers of ethylene oxide and
propylene oxide, a tetrafunctional block copolymer derived from sequential addition
of ethylene oxide and propylene oxide to ethylenediamine, dextran, a dioctyl ester
of sodium sulfosuccinic acid, a sodium lauryl sulfate, and an alkyl aryl polyether sulfonate.
49. The method of claim 47, wherein the ratio of the distance between the outer
periphery of the rotor and the inner surface of the wall to the attrition milling
media nominal size is about 6 to about 1.
50. The method of claim 47, wherein the attrition media has a mean particle size
selected from the group consisting of: (a) less than about 500 microns; (b) less
than about 300 microns; (c) less than about 250 microns; (d) less than about 200
microns; (e) less than about 100 microns; (f) less than about 75 microns; (g) less
than about 50 microns, (h) less than about 25 microns; (i) less than about 5 microns;
and (j) a mixture thereof.
51. The method of claim 47, wherein the attrition media is selected from the
group consisting of polymeric, zirconium oxide, zirconium silicate, glass, stainless
steel, titania, alumina, and 95% ZrO stabilized with yttrium.
52. The method of claim 47, wherein the working volume of the vessel is about
12 mL to about 33 mL.
53. The method of claim 47, wherein the volume of the dispersion is about 5 ml
to about 23 mL.
54. The method of claim 47, wherein the volume of the dispersion is less than
about 10 mL.
55. The method of claim 47, wherein the method further comprises maintaining
substantially uniform shear between the rotor and the and the vessel.
56. The method of claim 47, wherein at the completion of the rotation period,
the cosmetic product has an average particle size selected from the group consisting
of less than about 500 nm, less than about 400 nm, less than about 300 nm, and
less than about 100 nm.
57. The method of claim 56, wherein at least 90% of the milled cosmetic product
particles have a size less than that selected from the group consisting of less
than about 500 nm, less than about 400 nm, less than about 300 nm, and less than
about 100 nm.
58. The method of claim 56, wherein at least 95% of the milled cosmetic product
particles have a size less than that selected from the group consisting of less
than about 500 nm, less than about 400 nm, less than about 300 nm, and less than
about 100 nm.
59. The method of claim 56, wherein at least 99% of the milled cosmetic product
particles have a size less than that selected from the group consisting of less
than about 500 nm, less than about 400 nm, less than about 300 nm, and less than
about 100 nm.
60. The method of claim 47, wherein the dispersion is recirculated through the
vessel during rotation of the agitator.
Description
BACKGROUND
Wet media mills, such as the ones described in U.S. Pat. No. 5,797,550 issued
to Woodall, et al, and U.S. Pat. No. 4,848,676 issued to Stehr, are generally used
to mill or grind relatively large quantities of materials. These rather large media
mills are not generally suitable for grinding small or minute quantities. U.S.
Pat. No. 5,593,097 issued to Corbin recognizes the need for milling small quantities,
as small as 0.25 grams, to a size less than 0.5 micron to about 0.05 micron in
terms of average diameter in about 60 minutes.
The media mill described in the Corbin patent comprises a vertically oriented
open top vessel, a vertically extending agitator with pegs, a motor for rotating
the agitator, and a controller for controlling the rotational speed. The vessel
is a cylindrical centrifuge or test tube formed of a glass, plastic, stainless
steel, or other suitable material having an inner diameter of between 10 to 20
mm. The media suitable is described as any non-contaminating, wear resistant material,
sized between about 0.17 mm to 1 mm in diameter.
The particulates to be ground and the grinding media are suspended in a dispersion
and poured into the vessel. The agitator, with the peg end inserted in the vessel,
is spun. The Corbin patent also discloses that the pegs should extend to within
between about 1-3 mm of the sides of the vessel to provide the milling desired
in the shortest possible time without damaging the materials and producing excessive
heat. To avoid splattering created by vortexing of the material during mixing,
the top peg of the mixer is positioned even with the top of the dispersion. No
seal or cover is deemed needed during mixing or agitation if this practice is followed.
The Corbin patent also discloses that its micro media can be useful for forming
medicinal compounds, food additives, catalysts, pigments, and scents. Medicinal
or pharmaceutical compounds can be expensive and require much experimentation,
with different sizes and quantities. The Corbin patent discloses that the preferred
media for medicinal compounds are zirconium oxide and glass. Moreover, pharmaceutical
compounds are often heat sensitive, and thus must be maintained at certain temperatures.
In this respect, the Corbin patent discloses using a temperature control bath around
the vessel.
In the media mill of the type described in the Corbin patent, even if the vessel
is filled to the top peg, however, the rotating agitator in the dispersion creates
a vortex, which undesirably draws air into the dispersion and foams the dispersion.
Moreover, the open top configuration draws in contamination, making the mill unsuitable
for pharmaceutical products. The temperature-controlled bath could spill into the
open top container and further contaminate the product.
There is a need for a micro or small-scale media mill that avoids these problems.
The present invention is believed to meet this need.
SUMMARY
The present invention relates to a small-scale or micro media-mill and a method
of milling materials, such as pharmaceutical products. The present small-scale
mill, which can be vertically or horizontally oriented, can use a dispersion containing
attrition milling media and the product to be milled. The milling media can be
polymeric type, such as formed of polystyrene or cross-linked polystyrene having
a nominal diameter of no greater than 500 microns. Other sizes include 200 microns
and 50 microns and a mixture of these sizes.
In one embodiment, the mill has a relatively small vessel having an opening,
an
agitator, and a coupling, and a rotatable shaft mounted for rotation about a shaft
mount. The agitator is dimensioned to be inserted in the vessel through the opening.
Specifically, the agitator can have a rotor and a rotor shaft extending from the
rotor. The rotor shaft is connected to the rotatable shaft. The rotor is dimensioned
to be inserted in the vessel with a small gap formed between an outer rotating
surface of the rotor and an internal surface of the vessel. The coupling detachably
connects the vessel to the shaft mount. The coupling has an opening through which
a portion of the agitator, such as the rotor shaft, extends. The shaft mount seals
the vessel opening to seal the dispersion in the vessel. A seal can be provided
to seal the portion of the agitator or the rotor shaft while permitting the agitator
to rotate. The rotatable shaft can be driven by a motor or can be a motor shaft
of a motor, preferably a variable speed motor capable of 6000 RPM.
In one embodiment; the coupling can have a threaded portion for detachably mounting
to the shaft mount and a flange portion for detachably coupling to the vessel.
In another embodiment, the coupling is integrally formed with the vessel and has
a threaded portion for detachably mounting to the shaft mount.
The mill can include a cooling system connected to the vessel. In one embodiment,
the cooling system can comprise a water jacket. Specifically, the vessel comprises
a cylindrical inner vessel and an outer vessel spaced from and surrounding the
inner vessel. The inner and outer vessels form a chamber therebetween. The chamber
can be vessel shaped or annular. A flange connects the upper ends of the inner
and outer vessel. The outer vessel (jacket) has at least first and second passages
that communicate with the chamber. The cooling system comprises the outer vessel
with the first and second passages, which is adapted to circulate cooling fluid.
In an alternative embodiment, the vessel can comprise an inner cylindrical wall
having a bottom and an open top and an outer cylindrical wall spaced from and surrounding
the inner vessel. The inner and outer cylindrical walls are connected together
so that an annular chamber is formed therebetween. At least the first and second
passages are formed at the outer cylindrical wall and communicate with the chamber
to pass coolant. The bottom extends radially and covers the bottom end of the outer
cylindrical wall. The bottom can have an aperture that allows samples of the dispersion
to be withdrawn. A valve can close the aperture. Alternatively, the bottom can
have an observation window for observing the dispersion.
In another embodiment, the vessel can include at least one port through which
the dispersion is filled. The vessel includes at least two ports through which
the dispersion is circulated. In this respect, the cooling system comprises the
ports on the vessel for circulating the dispersion. The vessel can be horizontally oriented.
The rotor can be cylindrical, and can have tapered end surfaces. In one embodiment,
the rotor is dimensioned so that its outer periphery is spaced no larger than 3
mm away from an inner surface of the vessel, particularly when the dispersion contains
attrition media having a nominal size of no larger than 500 microns. The spacing
or the gap is preferably no larger than 1 mm, particularly when the dispersion
contains attrition media having a nominal size of no larger than 200 microns.
In another embodiment, the cylindrical rotor can have a cavity and a plurality
of slots that extend between an inner surface of the cavity and an outer surface
of the cylindrical rotor. In another embodiment, the cylindrical rotor can have
a plurality of channels extending to an outer surface of the cylindrical rotor.
In another embodiment, the cylindrical rotor can have a plurality of passageways
extending between the tapered end surfaces of the cylindrical rotor.
One method according to the present invention comprises providing a dispersion
containing a non-soluble product to be milled and attrition milling media having
a nominal size of no greater than 500 microns; inserting the dispersion into a
cylindrical vessel; providing an agitator and a coupling that closes the vessel,
the coupling having an opening through which a portion of the agitator extends,
the agitator comprising a cylindrical rotor and a shaft extending therefrom, wherein
the cylindrical rotor is dimensioned so that an outer periphery is no greater than
3 mm away from an inner surface of the cylindrical wall; inserting an agitator
into cylindrical vessel and sealingly closing the coupling, wherein the amount
of dispersion inserted into the vessel is so that the dispersion eliminates substantially
all of the air in the vessel when the agitator is fully inserted into the vessel;
and rotating the agitator for a predetermined period.
Another method according to the present invention comprises providing a dispersion
containing a non-soluble product to be milled and attrition milling media having
a nominal size of no greater than 500 microns; providing an agitator having a cylindrical
rotor and shaft extending therefrom; inserting the agitator in a horizontally oriented
cylindrical vessel and sealing the cylindrical vessel, the cylindrical rotor being
dimensioned to provide a gap of no greater than 3 mm between an outer surface of
the rotor and an inner surface of the vessel; providing at least one port through
the cylindrical vessel and maintaining the port at a highest point of the horizontally
oriented cylindrical vessel; filling the cylindrical vessel with the dispersion
until the dispersion drives out substantially all of the air in the vessel; and
rotating the agitator for a predetermined period.
The method further includes cooling the vessel by jacketing the vessel and flowing
water between the jacket and the vessel. Another method comprises externally circulating
the dispersion through a plurality of ports formed through the horizontally oriented
vessel to thereby cool the dispersion or refresh the dispersion.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present invention
will become more apparent from the following description, appended claims, and
accompanying exemplary embodiments shown in the drawings.
FIG. 1 illustrates a small-scale or micro-media mill according to one embodiment
of the present invention.
FIG. 1A illustrates an enlarged detailed view of the mill shown in FIG. 1.
FIG. 2 illustrates the media mill of FIG. 1, but with a different vessel.
FIG. 3 illustrates a small-scale or micro-media mill according to another embodiment
of the present invention.
FIG. 3A illustrates an enlarged detailed view of the mill shown in FIG. 3.
FIG. 3B illustrates an enlarged detailed view taken along area 3B of
FIG. 3A.
FIG. 4 illustrates a side view of a small scale or micro media mill according
to another embodiment of the present invention.
FIG. 5 illustrates another embodiment of an agitator and another embodiment
of a vessel that can be used with the media mill of FIGS. 1-4.
FIG. 6 illustrates the agitator of the type illustrated in the embodiments of
FIGS. 1-4.
FIG. 7-13D illustrate various agitator configurations that can be used with
the media mill of FIGS. 1-4.
DETAILED DESCRIPTION
Although references are made below to directions in describing the structure,
they are made relative to the drawings (as normally viewed) for convenience. The
directions, such as top, bottom, upper, lower, etc., are not intended to be taken
literally or limit the present invention.
A small-scale mill
1,
1A,
2 (FIGS. 1-4) according to the
present
invention is designed to mill relatively small amounts of dispersion to a size
ranging from microns to nanometers in a relatively short time, i.e., a few hours
or less, using attrition milling media, such as polymer type, e.g., cross linked
polystyrene media, having nominal size no greater than about 500 microns (0.5 mm)
to about 50 microns or mixtures of the sizes ranging between them. The performance
of the present scale mill is designed to provide the results comparable to the
DYNO-MILL and the NETZSCH ZETA mills. The mill
1,
1A,
2 according
to the present invention can have a provision for cooling the dispersion, which
allows increased agitator tip speed without overheating, to increase its efficiency
and allow milling of heat sensitive pharmaceutical products.
A vertically oriented mills
1,
1A is exemplified in FIGS. 1-3A.
The
mill
1,
1A generally comprises a container or vessel
10,
10A,
10B,
10C, an agitator or mixer
30, a coupling
50, and
a rotatable journaled shaft
120, which can be that of a motor
100.
The vessel
10,
10A,
10B,
10C has a substantially cylindrical
milling chamber and can be single walled
10C, as shown in FIGS. 5 and 6,
or jacketed (double-walled)
10,
10A,
10B, as shown in FIGS.
1-3A, to allow water cooling. The agitator
30, which comprises a rotor
32
and a shaft
40 extending from one end of the rotor
32, is preferably
a single piece to ease cleaning, and is adapted to be connected to a conventional
electric motor
100, which preferably is capable of rotating up to 6000 RPM.
A conventional motor controller
101 (FIGS. 1,
3,
4), such
as SERVODYNE Mixer Controller available from Cole-Parmer Instrument Co. of Vernon
Hills, Ill., can control the motor speed and duration. The coupling
50 is
mounted to the motor
100 and is coupled to the vessel
10 using a
sanitary fitting and a clamp C (shown in phantom in FIG. 3) to seal the vessel
10,
10A,
10B,
10C.
Referring to FIG. 1A, the vessel
10 in this embodiment is double
walled or jacketed to circulate a coolant. Specifically, the vessel
10 comprises
an inner cylindrical wall
12 and an outer cylindrical wall
14 spaced
from and concentric with the inner cylindrical wall
12. The outer wall
14,
however, need not be cylindrical or concentric relative to the inner wall
12.
It can have any configuration that allows water circulation to the inner cylindrical
wall
12. An annular mounting flange
16 holds together top end of
the inner and outer cylindrical walls
12,
14. The inner cylindrical
wall
12 has a bottom wall
13 enclosing its bottom end to form an
inner vessel (
12,
13). The outer cylindrical wall
14 also
has a bottom wall
15 enclosing its bottom end and spaced from the bottom
wall
13 to form an outer vessel (
14,
15). The outer vessel
(
14,
15) is spaced from the inner vessel (
12,
13) and
forms a vessel shaped chamber
17 that can be filled with water and circulated
to cool the dispersion during milling.
The outer cylindrical wall
14 has two openings
20, preferably positioned
diametrically opposite to each other and a pair of coolant connectors
22
aligned with the openings
20. Either of these connectors
22 can serve
as a coolant inlet or outlet. These connectors
22 can extend substantially
radially outwardly. The free end of each connector can have a sanitary fitting,
which includes an annular mounting flange
24 and a complementary fitting
(essentially mirror image thereof—not shown), adapted to be clamped with,
for example, a TRI-CLAMP available from Tri-Clover Inc. of Kenosha, Wis. These
mounting flanges
24 are configured substantially similar to the mounting
flanges
16,
52 connecting the vessel
10,
10A,
10B,
10C to the motor
100. All of these mounting flanges
16,
24,
52 can be adapted for a TRI-CLAMP, as described below. Each of these flanges
16,
24,
52 has an annular groove G for seating an annular
gasket
60 and a beveled or tapered surface B. The mounting flanges and the
gasket
60, which is FDA approved, adapted for the TRI-CLAMP are also available
from Tri-Clover Inc.
FIG. 2 shows another embodiment of the double walled vessel
10A, which
is substantially similar to that shown in FIGS. 1 and 1A. The difference is that
the bottom wall
13 of the inner cylindrical wall
12 in FIG. 2 is
exposed. In other words, the alternative vessel
10A of FIG. 2 has no outer
bottom wall
15 of FIG. 1A. The alternative vessel
10A has its bottom
wall
13 extending radially outwardly to the outer cylindrical wall
14.
The chamber
17 is annular instead of being vessel shaped (FIG. 2). The bottom
wall
13 can have a heat sink or a Peltier coolant (not shown) attached.
The bottom wall
13 also can have an observation window or an opening
205,
which can be sealed or can have a valve
210 that vents excess pressure build
up and/or allows a sample withdrawal. This way, minute amounts of dispersion can
be taken out and examined without having to take off the coupling
50. Alternatively,
the opening can be sealed using a self-sealing resilient material that permits
insertion of a syringe for withdrawing samples. The window
205 can have
a small chamber extending outwardly from the bottom (not shown). This chamber can
hold a small amount of dispersion so that it can be viewed through an observation
device. This chamber can be configured so that the dispersion is constantly circulated,
such as placing the window
205 in a location where the dispersion is constantly moving.
FIGS. 3 and 3A show another embodiment of the double walled vessel
10B,
which is substantially similar to that shown in FIGS. 1 and 1A. The primary difference
is that the outer bottom wall
15A can be threaded or screwed (or sealingly
mounted) into the outer cylindrical wall
14. In this respect, the outer
bottom wall
15A can have an annular groove (not numbered) that seats an
O-ring
74 or the like to provide a better water seal. Another difference
from the vessel of FIGS. 1 and 1A, is that a quick couple fitting
22A,
24A,
24B is used. The connectors
22A are threadlingly mounted to the openings
20 formed in the outer cylindrical wall
14. The connectors
22A
can use a commercially available quick connector or couple
24A, such as
⅛" PARKER series 60 Quick Couple. The quick couple
24A can be connected
to a flexible hose barb
24A, such as a commercially available stainless
steel ⅛" NPT×¼" hose barb. The double-walled vessels
10
and
10A can also use the quick couple fitting
22A,
24A,
24B
instead of the sanitary fitting type described above and illustrated in FIGS. 1-2.
Alternative to the double walled vessel is a single walled vessel
10C
shown in FIGS. 5 and 6. The single walled vessel
10C can be used when the
product to be milled is not heat sensitive or for milling a short period. The single
walled vessel is constructed similar to the inner vessel (
12,
13)
of the double walled vessel
10. A heat sink (not shown) can be attached
to its cylindrical wall
12 and bottom wall
13. The heat sink also
can be fan cooled. Another alternative cooling system can be a Peltier cooler,
which operates on the Peltier effect theory (cooling by flowing an electric current
through a Peltier module made of two different types of conductive or semiconductive
materials attached together). A Peltier module with a heat sink (Peltier coolant)
can be detachably attached to the vessel.
In the embodiments of FIGS. 1-3,
5, and
6, the mounting flange
52
of the coupling
50 is configured substantially the same as or complementary
to the annular mounting flange
16. The mounting flanges
16 and
52
are coupled facing each other with the gasket
60, such as a Tri-Clamp EPDM
black, FDA approved gasket, sandwiched therebetween, as shown in FIGS. 1A,
2,
and
3A. The gasket
60 has annular lower
62 and upper
64
protrusions that engage the respective grooves G formed in the mounting flanges
16,
52, and align the flanges
16 and
52. A TRI-CLAMP
C (see FIG. 3) can engage the periphery P and the beveled surfaces B of the mounting
flanges
16,
52. When these flanges are aligned, they form a trapezoidal
profile. Tightly wrapping the TRI-CLAMP around the periphery and the beveled surfaces
B squeezes the flanges
16,
52 together to provide a sealed connection.
The mounting flanges
24 of the connectors
22 (FIGS. 1,
1A,
2) can be connected to their respective water source and drain pipes (not
shown) in the same way as the vessel
10,
10A,
10B,
10C
is connected to the coupling
50, as just described, using a gasket
60
and a TRI-CLAMP C.
Referring to the embodiments of FIGS. 1-3A, the coupling
50 also
has a cylindrical portion
54 extending from its mounting flange
52.
The flange
52 has a central opening
56 and a stepped recess
58
concentric with the opening
56. The recess
58 seats a seal, which
can be a lip or mechanical seal ring
70 having a complementary configuration.
Specifically, the seal ring
70 can be made from PTFE with a Wolastonite
filler and can have an L-shaped (cross-sectional) profile as shown in detail in
FIG. 3B. The seal ring
70 also can include a concentric O-ring
71
or the like, as shown in FIG. 3B. The opening
56 is dimensioned only slightly
larger than the agitator's shaft
40. The seal ring
70 is adapted
to engage the shaft
40 and seal the same while permitting the agitator
30
to rotate.
Referring to FIGS. 1A,
2,
3A, the cylindrical portion
54
is threaded on its inner side so that it can be attached to the motor
100.
Specifically, the coupling
50 is attached to a shaft mount
110, which
comprises an annular flange
112 and a downwardly extending cylindrical member
114. The cylindrical member
114 has an outer threading for threadingly
mating with the threaded cylindrical portion
54 of the coupling
50.
The flange
112 is mounted to the motor using bolts
200 or the like.
The motor
100 can be mounted to a stand or fixture
150 via the flange
112, using bolts
200. The stand
150 allows the motor
100
and the vessel
10,
10A,
10B,
10C to be oriented vertically,
as shown in FIGS. 1,
1A,
2, and
3.
The shaft mount
110 has a central through hole
115 dimensioned
larger than the shaft
40. The distal (lower) end of the cylindrical member
114 has an annular projection
116 that bears against the seal ring
70 (see FIG. 3B) and holds the seal ring
70 in place. The coupling
50 has an annular end face
55 that abuts against a complementary
face or shoulder
117 formed on the distal (lower) end of the cylindrical
member
114, adjacent to the annular projection
116. The end face
55 provides a positive stop and maintains proper seal compression when the
coupling
50 is mounted to the shaft mount
110. In this respect, referring
to FIG. 3A, the mounting flange
52 can also include an O-ring
72
positioned in an annular groove
59 formed on the upper end face
55
to provide additional seal. As the temperature of the dispersion increases during
milling, expanding air under pressure is designed to escape through the seal ring
70, while maintaining liquid seal. In this respect, the cylindrical member
114 has a vent opening
118 to vent any air seeping through the seal
ring
70.
The rotor shaft
40 comprises a larger diameter portion
42 and a
smaller diameter portion
44 having a threaded free end
45. A tapered
section
46 extends between these portions
42,
44. The rotor
30 is attached to the motor
100 by inserting the smaller diameter
portion
44 into a hollow motor shaft
120 and threading a nut
49
or a manual knob
49A (FIG. 3) onto the threaded end
45, which tightly
pulls the tapered section
46 against the lower end or mouth of the hollow
shaft
120, compressively attaching the agitator shaft
40 to the hollow
motor shaft
120. The nut
49 or the knob
49A can be covered
with a safety cap
47 (FIG. 3), which can be mounted to the top end of the
motor
100 using a base
48. The cap
47 can be threadedly mounted
to the base
48. The tapered section
46 also eases the insertion of
the shaft
40 through the seal ring
70 and prevents tear or damage
to the seal ring
70. At least around a section CP of the large diametered
shaft portion
42 contacting the seal
70 is preferably coated with
a wear resistant coating, such as a hard chrome coating to prevent wear.
Although the above-described mill
1 (FIGS. 1-3B) has been described
and shown in a vertical configuration, the present invention also contemplates
a horizontally oriented mill
2, as shown in FIG. 4. The horizontally oriented
mill
2 is substantially similar to the vertically oriented mill
1
shown in FIGS. 1-3, except for the vessel and coupling configuration. In the horizontally
oriented mill, a mounting bracket
160 is attached to the motor
100
via the shaft mount
110 so that the mill
2 is stably supported in
the horizontal position, as shown in FIG. 4. In the horizontally oriented mill
2, its vessel
10D can be attached to the motor via a threaded coupling
16′, and the shaft
40 can be sealed via a single or double
mechanical seal, or a lip seal
70′ (shown in phantom).
Referring to FIG. 4, the vessel
10D for the horizontally oriented
mill
2 is substantially similar to the singled walled vessel
10C
(FIGS. 5 and 6), except that the flange
16 (FIGS. 5 and 6) has a threaded
coupling
16′, substantially similar to the threaded coupling
50
shown in FIGS. 1-3A. The vessel
10D has an open cylindrical wall
12,
with one closed by an end wall
13. The threaded coupling
16′
is integrally or monolithically formed at the opposite open end. The vessel
10D,
however, can be configured like the singled walled vessel
10C for use with
the afore-described sanitary fitting.
The vessel
10D is illustrated with four fill/drain/cooling ports P
1-P
4
for illustrative purposes only. Only one port is needed in the horizontally oriented
mill
2. The ports P
2-P
4 are radially extending through the
cylindrical wall
12 of the vessel
10B, whereas the port P
1
is axially extending from the end wall
13 of the vessel
10B. In one
embodiment, the vessel
10D can have a single top fill port P
2 or
P
3. In such an embodiment, it is especially desirable for the top port P
2
or P
3 to be located at or along the highest point of the milling chamber,
i.e., at 12 O'clock position for a cylindrical vessel
10D, as this allows
the chamber to be filled so that all of the air is displaced from the chamber.
The absence of air in the milling chamber during operation prevents the formation
of foam and enhances milling performance.
Alternatively, the horizontally oriented vessel
10D can contain
two or more ports, such as two top radial ports P
2 and P
3, a single
axial port P
1 and a single top radial port P
3, or a single top radial
port P
3 and a single bottom radial port P
4. In such embodiments,
the dispersion can be externally circulated through the vessel
10D, where
one port acts as an outlet and the other an inlet. The dispersion can be cooled
or replenished during the circulating process. Using two ports, one can recirculate
(or add) the process fluid and/or attrition media via an external vessel and pump
(not shown). If the attrition media has to remain in the vessel, the outlet port
can be fitted with a suitable screen or filter to retain the media during operation.
Referring to FIGS. 5-13D, the rotor
32,
32A-
32J (collectively
"32") for both the vertically and horizontally oriented mills
1,
1A,
2 can have different geometric configurations. The agitator
30 is
preferably made of stainless steel or teflon or stainless steel with a teflon coating.
In this respect, the TRI-CLAMP can be made of 304 stainless steel. The components
that are exposed to the dispersion also can be made of 316 stainless steel. In
fact, all of the metal components, except the clamp and the motor can be made of
316 stainless steel. Alternatively, all metal components that become exposed to
the dispersion can be made of any material that is resistant to crevice corrosion,
pitting, and stress corrosion, such as an AL-6XN stainless steel alloy. An AL-6XN
alloy meets ASME and ASTM specifications, and is approved by the USDA for use as
a food contact surface.
The rotor
32 also can comprise a variety of geometries, surface textures,
and surface modifications, such as channels or protrusions to alter the fluid flow
patterns. For example, the rotor
32 can be cylindrical (straight), as shown
in FIG. 5, or cylindrical (tapered ends T
1, T
2) as shown in FIGS.
1-4 and
6. In other illustrated embodiments, the rotor
32 can be
hexagonal (FIG. 7), ribbed (FIG. 8), square (FIG. 9), cylindrical with channels
(FIGS. 10 and 11), cylindrical with passageways (FIG. 12), and cylindrical with
a cavity and slots (FIGS. 13-13D). All of these embodiments can have tapered end
surfaces T
1, T
2.
Specifically, the hexagonal rotor
32A (FIG. 7) has six planar
sides
202. The ribbed rotor
32B (FIG. 8) has hexagonal sides
202
as shown in FIG. 7, but with six ribs
204 extending respectively from the
middle of each of the six sides
202. The square rotor
32C (FIG. 9)
has four planar sides
206. The cylindrical rotor
32D (FIG. 10) has
four channels
208 that are perpendicular to each adjacent channels
208.
The cylindrical rotor
32E (FIG. 11) is substantially identical to the cylindrical
rotor
32D of FIG. 10, but has six channels
208 instead of four, symmetrically
angled and spaced apart. The cylindrical rotor
32F (FIG. 12) has four angled
passageways
210, extending from the tapered or conical end surfaces T
1,
T
2. These angled passageways have four openings at the first tapered end
surface T
1 and four openings at the second tapered end surface T
2.
An imaginary circle intercepting the four openings at the first tapered end surface
T
1 has a greater diameter than an imaginary circle intercepting the four
openings at the second tapered end surface T
2.
The cylindrical rotors
32G,
32H,
32I,
32J (FIGS.
13-13D) each have a concentrical cylindrical cavity
212 opening to the second
tapered surface T
2. Depending on the material and the media mill size, these
rotors can have at least three (not shown) equally spaced apart axially extending
flow modifying channels
214. The rotors
32G-
23J are respectively
shown with four, six, eight, and nine channels
214. These slots
214
can also be angled as shown, or spiraled or helically configured (not shown) relative
to the rotational axis. In the embodiment of FIG. 13A, four channels
214
can be angled 90° relative to the adjacent channels. In the embodiment of
FIG. 13B, the six channels
214 can be angled 60°. In the embodiment
of FIG. 13C, the eight channels
214 can be angled 45°. In the embodiment
of FIG. 13D, the nine channels
214 can be angled 40° relative to the
vertical. In alternative embodiments (not shown), the channels
214 can radially
extend from the axis of the rotor
41.
The rotors
32G-
32J of FIGS. 13A-13D can act as a pump. That is,
these rotors can withdraw fluid into the cavity
212 and eject fluid outwardly
through the channels
214, or conversely withdraw fluid into the cavity through
the channels
214 and eject fluid outwardly through the cavity
212,
depending on the direction of the rotation, to modify the dispersion flow pattern.
In other embodiments (not shown), rotors also can contain pegs, agitator discs,
or a combination thereof.
Referring to the cylindrical rotor
32 shown in FIGS. 1-6, its outer
peripheral cylindrical surface
36 and the inner cylindrical surface
12"
of the inner cylindrical wall
12 of the vessel
10,
10A,
10B,
10C,
10D are dimensioned to provide a small gap X. The gap X is preferably
no greater than 3 mm and no smaller than 0.3 mm. In general, this gap X should
be approximately 6 times the diameter of the milling media, which is preferably
made of cross linked polystyrene or other polymer as described in U.S. Pat. No.
5,718,388 issued to Czekai, et al. The largest attrition milling media preferably
is nominally sized no greater than 500 microns (0.5 mm). Presently, the smallest
attrition milling media contemplated is about 50 microns. Nonetheless, it is envisioned
that a smaller attrition milling media can be suitable for milling certain non-soluble
products, such as pharmaceutical products, which means that the gap X can be made
smaller accordingly.
The vessel size can vary for milling small amounts of dispersion. Although the
present invention is not limited to particular sizes, in the preferred embodiment,
the inner diameter of the vessel is between ⅝ inch to 4 inches. By way of
examples only, milling chamber of the vessel
10,
10A,
10B,
10C, and
10D and the cylindrical rotor
32 can have the dimensions
specified in Tables 1 and 2.
| TABLE 1 |
|
| (STRAIGHT ROTORS) |
| |
TRI-CLAMP Size VESSEL/COUPLING |
