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Publication numberUS2919862 A
Publication typeGrant
Publication dateJan 5, 1960
Filing dateAug 24, 1954
Priority dateAug 31, 1953
Publication numberUS 2919862 A, US 2919862A, US-A-2919862, US2919862 A, US2919862A
InventorsBeike Hans, Erberich Gunther
Original AssigneeKnapsack Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process and apparatus for comminuting solid viscous substances, with a liquefied gas as a precooling agent
US 2919862 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Jan. 5, 1960 H. BEIKE E'rAL 2,919,852



Germany, assignors to Knapsack-Griesheim Aktiengesellschaft, Knapsack Bezirk Koln, Germany, a company of Germany Application August 24, 1954, serial No. 451,735 Claims priority, application Germany August 31, 1953 4 Claims. (Cl. 241-23) The present invention relates to a process and apparatus for comminuting substances that are solid and viscous at normal or room temperatures.

The term comminuting means herein subdividing to any degree of fineness, especially to the state of powder, whilst the term comminuting device means herein any grinding device, pulverizing device or mill.

The process and apparatus of the invention are suitable for comminuting, for example, thermoplastics, such as polyethylene, polyisobutylene, polyvinylchloride and other polymers; poly-addition products, such as polyurethanes; rubber, caoutchouc, synthetic caoutchouc, bitumen or asphalt. The invention is also applicable to materials comprising substances that are, as such, solid and more or less brittle at normal or room temperatures, for example polyvinyl chloride, but which have been rendered plastic and viscous by the addition of a plasticizer, e.g. tricresylphosphate.

The process of the invention consists in first treating the solid viscous substance or material with a cooling agent until it has become brittle and then comminuting it whilst it is brittle.

Preferably, the embrittlement is effected by maintaining the substance or material for a controlled period of time in intimate contact with the cooling agent.

As cooling agent, there maybe used any liquid or liquefied gas of low boiling point at a'temperature-between about 80 C. and about -200 C. Liquid nitrogen and liquid -air are very suitable. l

The process may be carried out as follows: The material to be comminuted is introduced directly into a bath of a low-boiling liquefied gas having a temperature of between 80 C. and 200 C. The material is kept in the bath long enough to be cooled to the temperature of the bath and thereby converted into a brittle state. The brittle material is conveyed to and operated upon by a comminuting device.

In order to cool the viscous material to low temperatures and to keep it cool until it has entered the comminuting device, it is desirable to prevent, as far as possible, any introduction of vair-which would warm the materialto the material on its way from the liquefied gas bath to the comminuting device as well as in the comminuting device itself. For this purpose, a liquefied gas seal may be provided by suitably arranging and locating the liquefied gas bath and the conveyor casing which is advantageously associated with the bath and which contains'a screw conveyor, or the like, leading to the comminuting device. v

The seal effectively prevents the relatively warm air from penetrating into the comminuting device. In a very simple arrangement, the liquefied gas entirely fills part of the conveyor casing which, for the purpose in question, is upwardly inclined. Y The supply of the liquefied gas may be regulated in dependence upon the level of the liquefied gas bath and thus of the liquefied gas seal.

Patented Jan. 5, 196,0

For this purpose, a valve is advantageously installed in the supply line for the liquefied gas from a tank in whic it is stored.

For pre-cooling as far as possible the material tov be comminuted and for keeping all essential parts of the apparatus cool, it is convenient to use the liquefied gas vapours which are inevitably evolved in the apparatus. For example, part of the vapours which are formed over the liquefied gas bath due to the introduction of the material to be comminuted which has a relatively higher temperature is passed, if desired, by sucking off by means of a fan or the like, through the incoming material to be comminuted aud through the supply vessel containing the said material. Another part of the vapours flows towards the comminuting device. Likewise, the liquefied gas vapors which are evolved in the conveyor casing arranged between the liquefied gas bath and the comminuting device are sucked ofi into the latter thus serving to cool it.

The speed of the conveyor may be regulated so as to ensure a complete cooling of the material in its passage through the bath of liquefied gas and to the comminuting device. lf only partial cooling is required, the desired low temperature can be attained by suitably regulating the time during which the material is in the liquefied gas bath and/or in the area between the liquefied gas bath and the comminuting device. This may be effected by appropriately forming the screw and adjusting its speed. In this manner the material to be comminuted may be cooled uniformly to any desired temperature lying above that of the cooling liquid.

The apparatus for carrying out the process of thel invention may comprise a vchamber or container which contains a cooling agent for cooling the viscous substances, means for introducing the latter into the chamber or container and a conveyor for transporting them therefrom, after they have been converted into `a brittle state by the action of the cooling agent, into a comminuting device.

For example, the apparatus comprises a supply vessel for the viscous material, a supply vessel for the cooling agent and a chamber or container into which the viscous material and the cooling agent .are introduced from their respective supply vessels. The chamber or container is provided in its interior with a conveyor to transport the substances in the manner described aboveinto the comminuting device. It is of advantage to construct the apparatus so that the chamber for the liquefied gas `and the material to be comminuted is mounted before the conveyor casing containing the conveyor screw. Said chamber, being in connection with .the supply vessel for the material to be comminuted, is arranged substantially vertically and at an angle with the conveyor casing. The liquefied gas thus entirely fills part of the conveyor casing whereby a complete liquefied gas seal is obtained. In this manner, the conveyor casing with the conveyor screw and the comminuting device itself are effectively and completely protected from any access of relatively warm air. A quick and thorough cooling and, consequently, a sufi'icient embrittling of the material to be comminuted are thus assured.

An apparatus suitable for use in carrying out the process of this invention is illustrated diagrammatically by way of example in the single figure of the accompanying drawing which is in section.

A supply vessel l1 contains the plastic material' toibe comminuted. The cooling agent, for instance liquid nitrogen, is stored as indicated at 2 in a suitably insulated tank. This insulation and the insulation of other parts of the apparatus is marked 23. The plastic material drops on to a conveyor 3 which takes it into the liquefied'g'as bath 4 in a chamber 5 in to which the cooling' agent is conducted by means` of a tube 6. 1 Chamber ,51 is vv.sucjf ceeded by a conveyor casing 7 containing a screw conveyor 8. Chamber 5 and conveyor casing 7 are at such an angle that the bath of cooling agent forms a liquid seal which completely separates conveyor casing 7 from chamber 5 and effectively protects it from outside access of air which might penetrate into the apparatus from supply vessel 1 through casing 7. 1n order to keep the bath of liquid cooling agent at a constant level, it is of advantage to adjust its supply, dependent on the level of the liquid, by a valve 9 which may be operated by hand.

When the material to be comminuted, which has a relatively higher temperature, enters the liquefied gas bath, lively evaporation sets in. The relatively cold gases evolved thereby are wholly or partially sucked off by a fan 10 installed above the supply vessel 1 and thus serve to precool the material. A further part of the gases may be conducted through a conduit 11 and also a shaft 12 into a comminuting device 13 in order also to keep the latter as cool as possible. The quantity of the gas volume can be adjusted at will in each particular case by shutters 14 and 15.

The suction effect which the comminuting device 13 necessarily has upon the spaces opening into the mill, i.e. conveyor casing 7 and conduit 11, can be adjusted at will by an adjustable valve 19 installed in a conduit 20 behind the comminuting device. In this manner, by throttling the blowing conduit 20, the sucking effect of the comminuting device can be regulated in such a manner that only cool liquefied gas is sucked in; the amount of the latter can be limited without difficulty so that the amount of cool liquefied gas sucked in is substantially equal to the amount of vapours evolved within the apparatus.

The comminuting mill 13 is similar to the type shown in U.S. Patent 2,609,150 to Bludeau which patent is directed to the mechanical pulverization of refrigerated plastics. As seen in Fig. 5 of this patent the paddle wheel mill 52 operates on the principle of a ventilator. Briefly, vaporized refrigerant is drawn from the heat exchanger 56 by and into the mill 52 through passage 59 and is discharged by the mill through line 54 leading from the mill. The operation is apparent from Fig. 5 of the drawing of the above cited patent and the accompanying description.

The screw conveyor 8 in casing 7 is rotated by a gear 16, the pitch and the speed of the screw conveyor being adjusted in such a manner that the material to be comminuted remains suiciently long in the liquefied gas, i.e. until it has assumed the desired low temperature. The now brittle material is dropped through shaft 12 into the comminuting device 13 where it can be comminuted without diiculty to yield a powder. The vapours evolved in conveyor casing 7 are, likewise sucked ofi' through the device 13, thus keeping the latter cool so that also by the comminuting process no heat is evolved in the apparatus that could not be compensated for. Moreover, all parts of the apparatus that, either directly or indirectly, come into contact with the liquefied gas and/or the cooled material to be comminuted are provided with a suiciently strong insulating layer as indicated at 23.

The resulting powdered plastic of normal grain size is fed through a funnel 17 into a collector 1S sealed against external air, whereas--throttle 19 being open-the very fine powder is blown together with the evolved gas through conduit 20 into a filter bag 21 and then collected in a container 22.

The apparatus may be modified in various ways and is not limited to the above example of execution. In particular, the comminuting device and the chambers before and behind it and the conveyors for the material to be comminuted may be arranged and constructed as desited, depending upon the purposes of each individual case, provided that care istaken that by appropriate measures the material is in intimate contact with the cooling agent for a sufficient time and, moreover, that any undesired access of relatively warm external air to the cooled material is prevented as far as possible. The process of the invention may naturally be applied not only to the cold comminuting of thermoplastics but can be used wtih equal success for comminuting other substances whenever the material to be comminuted should be rendered especially brittle by low-cooling, or the access of air to the material should be prevented.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

l. Apparatus for comminuting a solid viscous substance comprising a chamber, a supply vessel for a solid viscous substance communicating with said chamber, means for supplying a liquefied gas as a cooling agent to said chamber, said means providing an excess of liquid cooling agent and thereby maintaining a liquid pool in said chamber, means for supplying the substance to a point below the pool level, means for withdrawing cooled substance in a state of embrittlement, said withdrawal means including a conduit connected at one end to said chamber at a point below the level of said pool and leading upwardly therefrom to a point at least above the liquid level of said pool, conveyor means within said conduit for withdrawing cooled substance from said chamber and conveying it upwardly through said conduit, a comminuting device associated with the other end of said conduit for receiving upwardly conveyed substance in a state of embrittlement and comminuting the same, a second conduit establishing vapor communication between said chamber at a level above the liquid pool level and said point above the liquid level of said pool at which the aforesaid conduit terminates adjacent the comminuting means whereby vapors of the cooling agent evolved in the chamber flow to said comminuting device, and means positioned beyond the comminuting means for regulating the ow of vapor from said chamber through the comminuting means.

2. Apparatus according to claim l wherein means are supported by the supply vessel for withdrawing vaporized cooling agent directly into said substance supply vessel from said chamber for precooling the solid viscous substance supply.

3. The process for comminuting a solid viscous substance comprising the steps of supplying liquefied gas as a cooling agent to a closed cooling zone while maintaining a liquid pool of said cooling agent in said zone, supplying below the pool level a solid viscous substance from a supply zone, cooling the supplied solid viscous substance to a temperature at least as low as that required for maintaining the substance in a state of ernbrittlement, withdrawing embrittled substance from said zone at a point below the level of said pool by conveying the same upwardly to a point at least above the liquid level of said pool while maintaining said withdrawn substance in said state of embrittlement, comminuting said upwardly-conveyed substance while at said temperature, withdrawing vaporized cooling substance from said cooling zone, and cooling said solid viscous substance during comminuting with said withdrawn vaporized cooling substance, and regulating from a point beyond and spaced apart from the comminuting point the amount of said vaporized cooling substance used to cool the solid viscous substance during the comminuting step.

4. The process of claim 3 wherein vaporized cooling agent is withdrawn directly from said cooling zone and passed directly therefrom into said supply zone for the viscous substance to precool said viscous substance.

(References on follog page) References Cited in the file of this patent UNITED STATES PATENTS Gerner Mar. 30, 1880 Algert Apr. 2, 1907 Novotny July 22, 1930 Atwell Jan. 23, 1934 Hurt Oct. 23, 1934 Runyon Aug. 27,1935 Miller July 2, 1940 Cuno Apr. 25, 1944 Arnold May 14, 1946 6 Hill Aug. 17, 1948 Bludeau May 8, 1951 Hendry et al. Jan. 29, 1952 Bludeau Sept. 2, 1952 FOREIGN PATENTS Germany Aug. 7, 1939 OTHER REFERENCES only one pass, by Gerard Miller.

Food Engineerm' s,

July 1951, pages 36 and 37.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US226057 *Mar 5, 1880Mar 30, 1880 Henry gerner
US849037 *Sep 17, 1906Apr 2, 1907Joseph AlgertOre crushing and screening mill.
US1771139 *Mar 12, 1928Jul 22, 1930John Stogdell StokesMethod of making substantially anhydrous finely-divided synthetic resins
US1944857 *Jun 19, 1931Jan 23, 1934Standard Oil CoQuick freezing process and refrigerant
US1978204 *May 16, 1934Oct 23, 1934Roy J HurtProcess of separating rubber from metal in a composite article
US2012694 *Jul 8, 1933Aug 27, 1935Edward HardingCrusher and pulverizer
US2206419 *Oct 21, 1937Jul 2, 1940Girdler CorpWorking of solidified plastic materials
US2347464 *Dec 8, 1939Apr 25, 1944Lehon CompanyMethod of pulverizing resinous and thermoplastic materials
US2400382 *Jul 29, 1943May 14, 1946Arnold Gerald DClosed hammer mill circuits
US2447249 *Oct 13, 1944Aug 17, 1948Marison CompanyMethod of refrigerating an article by contact with a vaporizable refrigerant
US2552029 *Apr 10, 1946May 8, 1951Union Carbide & Carbon CorpCold treating machine
US2583697 *Jun 5, 1950Jan 29, 1952Hendry Jr John LProcess of comminuting food products
US2609150 *Nov 5, 1949Sep 2, 1952Union Carbide & Carbon CorpMechanical pulverization of refrigerated plastics
DE679501C *Jul 30, 1938Aug 7, 1939Otto Werber Vorm Frick & WerbeSpeisevorrichtung fuer Zufuehrung des Mahlgutes zu Muehlen unter gleichzeitiger Kuehlung
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3072347 *Nov 2, 1961Jan 8, 1963Du PontMetal processing
US3172546 *May 19, 1961Mar 9, 1965Union Carbide CorpSize reduction of biological substances
US3319072 *Apr 20, 1964May 9, 1967Air Prod & ChemCryogenic cooling system
US3363846 *Dec 16, 1965Jan 16, 1968Nuclear Materials & EquipmentMethod of and apparatus for producing small particles
US3399838 *May 13, 1966Sep 3, 1968Nat Oats CompanyReduction of cereal grains to flour
US3416977 *Apr 1, 1966Dec 17, 1968Union Carbide CorpCryogenic cooling
US3507425 *Mar 28, 1968Apr 21, 1970NasaMethod and apparatus for cryogenic wire stripping
US3583172 *Jun 30, 1969Jun 8, 1971Union Carbide CorpCryogenic cooling of concrete
US3614001 *Dec 23, 1968Oct 19, 1971Hans BeikeMethod and apparatus for pulverizing materials
US3633830 *May 12, 1969Jan 11, 1972Linde AgProcess and apparatus for the comminution of soft material
US3756518 *Mar 8, 1971Sep 4, 1973Bailey WApparatus for processing resin
US3774855 *Oct 12, 1971Nov 27, 1973Klocher Humboldt Deutz AgGrinding method and vibrating mill for performing this method
US4222527 *Feb 22, 1979Sep 16, 1980Union Carbide CorporationCryopulverizing packed bed control system
US4273294 *May 31, 1979Jun 16, 1981Air Products And Chemicals, Inc.Method and apparatus for cryogenic grinding
US4342647 *May 29, 1980Aug 3, 1982The Commonwealth Industrial Gases LimitedTreatment of scrap
US4619113 *Jun 20, 1985Oct 28, 1986L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges ClaudeProcess and installation for cooling a powder by means of a refrigerating fluid
US4894105 *Nov 4, 1987Jan 16, 1990Basf AktiengesellschaftProduction of improved preimpregnated material comprising a particulate thermoplastic polymer suitable for use in the formation of substantially void-free fiber-reinforced composite article
US5128198 *Oct 25, 1989Jul 7, 1992Basf AktiengesellschaftProduction of improved preimpregnated material comprising a particulate thermoplastic polymer suitable for use in the formation of a substantially void-free fiber-reinforced composite article
US5203511 *Mar 8, 1990Apr 20, 1993Air Products And Chemicals, Inc.Method for fine grinding
US5431348 *Aug 19, 1993Jul 11, 1995Debio Recherche Pharmaceutique SaUltracentrifugal disintegrator and its use for the cryocomminution of heat sensitive material
US5456085 *Mar 7, 1994Oct 10, 1995Popp; James L.Process and apparatus for cryogenically cleaning residue from containers and reducing the bulk volume thereof
US5606860 *Apr 12, 1995Mar 4, 1997Popp; James L.Process and apparatus for cryogenically cleaning residue from containers and reducing the bulk volume thereof
US5761912 *Mar 3, 1997Jun 9, 1998Popp; James L.Process and apparatus for cryogenically cleaning residue from containers and reducing the bulk volume thereof
US5887750 *Feb 12, 1997Mar 30, 1999James L. PoppCommodity container
US6145323 *Mar 29, 1999Nov 14, 2000James L. PoppProcess and apparatus for cryogenically cleaning residue from containers
US8003208Mar 3, 2009Aug 23, 2011Toray Fluorofibers (America), Inc.Hydrophilic fluoropolymer material
US8132747Mar 3, 2009Mar 13, 2012Toray Fluorofibers (America), Inc.Method of making hydrophilic fluoropolymer material
US8132748Mar 3, 2009Mar 13, 2012Toray Fluorofibers (America), Inc.Method of making hydrophilic fluoropolymer material
US8459579 *Feb 1, 2012Jun 11, 2013Michael Donckers II J.Method of making hydrophilic fluoropolymer material
US20100224710 *Mar 3, 2009Sep 9, 2010Donckers Ii J MichaelMethod of making hydrophilic fluoropolymer material
US20100224712 *Mar 3, 2009Sep 9, 2010Donckers Ii J MichaelMethod of making hydrophilic fluoropolymer material
US20100227110 *Mar 3, 2009Sep 9, 2010Donckers Ii J MichaelHydrophilic Fluoropolymer Material
US20120128979 *Feb 1, 2012May 24, 2012Toray Fluorofibers (America), Inc.Method of Making Hydrophilic Fluoropolymer Material
DE1607462B1 *Dec 27, 1967Dec 3, 1970Beike Dipl Ing HansVerfahren zur Feinzerkleinerung von durch Eintauchen in verfluessigtes Gas sproede gemachten festen Stoffen
DE1929232A1 *Jun 10, 1969Jan 29, 1970Succ George & Co S P R LVerfahren zum Zerkleinern von Schrott
EP0424550A1 *Oct 23, 1989May 2, 1991Karl Reinhard ZeissProcess for preparing mixtures of asphalt and a filler or for spreading asphalt on a surface
EP0584712A1 *Aug 18, 1993Mar 2, 1994Debio Recherche Pharmaceutique S.A.Ultra-centrifugal mill and its implementation for cryogenically milling heat-sensitive material
U.S. Classification241/23, 241/DIG.370, 62/64, 241/65, 241/62, 62/374
International ClassificationC10C3/16, B02C19/18, B29B13/02, B29B13/10
Cooperative ClassificationY10S241/37, B29B13/021, B02C19/186, B29B13/10, C10C3/16
European ClassificationB02C19/18C, C10C3/16, B29B13/10, B29B13/02B