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Publication numberUS3895760 A
Publication typeGrant
Publication dateJul 22, 1975
Filing dateNov 9, 1973
Priority dateMay 18, 1973
Publication numberUS 3895760 A, US 3895760A, US-A-3895760, US3895760 A, US3895760A
InventorsSnyder Francis Henry
Original AssigneeLone Star Ind Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for shattering shock-severable solid substances
US 3895760 A
Abstract
The improved method and apparatus for shattering, comminuting or reducing the size of shock-severable solid substances or materials, such as ores, minerals and rocks, includes charging a pressure vessel, which forms a first zone, with the solid material, introducing a compressible working fluid into said vessel, and thereafter causing the solid material to be entrained in the expanding working fluid and discharging the entrained material into a second zone of lower pressure though a system wherein the entrained material is continuously subjected to shock phenomena from the time it exits from said first zone until it is discharged into said second zone. The method and apparatus also includes a dual system to impact high velocity material streams against each other to shatter and reduce the size of said solid material. The apparatus injects the working fluid in such a manner and so locates and operates a quick-opening valve so as to prevent significant wear or damage to the valve.
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Description  (OCR text may contain errors)

United States Patent Snyder July 22, 1975 [5 METHOD AND APPARATUS FOR 3,545,683 12/1970 Schulte 241/5 SHATTERING SHOCK SEVERABLE SOLID 3,614,000 10/1971 Blythe 241/5 SUBSTANCES Primary Examiner Granville Y. Custer, Jr. 1 1 lmemml Francis Henry Snyder Newtown, Attorney, Agent, or FirmKenyon 8; Kenyon Reilly Conn- Carr & Chapin [73] Assignee: Lone Star Industries, Inc.,

Greenwich, Conn. [57] ABSTRACT [22] Filed: Nov. 9, 1973 'cl'girellzplrtoyed method and apparatus for shattering, g or reducing the size of shock-severable [21] App]. No.: 414,195 solid substances or materials, such as ores, minerals and rocks, includes charging a pressure vessel, which q Apphcauon Data forms a first zone, with the solid material, introducing [63] Commuanommpa" 9 S May a compressible working fluid into said vessel, and z z g l t s g of thereafter causing the solid material to be entrained in one the expanding working fluid and discharging the entrained material into a second zone of lower pressure [221 Ccl1 223558 1191432 though a System wherein the entrained material is com I 241/5 39 40 tinuously subjected to shock phenomena from the [58] 0 earc time it exits from said first zone until it is discharged into said second zone. The method and apparatus also [56] References Cited includes a dual system to impact high velocity material UNITED STATES PATENTS streams against each other to shatter and reduce the 2,602,595 7/1952 Thomas.. 241/39 size of said solid material. The apparatus injects the 2.974.886 3/1961 Nagcl 241/39 working fluid in such a manner and so locates and op- 3J84'169 5/1965 Friedman 241/40 erates a quick-opening valve so as to prevent signifi- 3257.080 6/1966 Snyder 241/5 Cant wear or damage to the valve 3.352.498 11/1967 Schulte..v 241/5 X 3.482.786 12/1969 Hogg 241/40 X 39 Claims, 5 Drawmg Figures my, Ti 1T1.

llo lid PATENTEDJUL 22 1915 SHEET llm METHOD AND APPARATUS FOR SHATTERING SIIOCK-SEVERABLE SOLID SUBSTANCES This application is a continuation-in-part of copending application Ser. No. 361 ,610, filed on May 18, 1973, now abandoned, which latter application is a continuation of application Ser. No. 170,087, filed Aug. 9, 1971, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to processing, and more particularly to improvements in methods and apparatuses for shattering or efiecting size reduction of shockseverable solid materials such as ores, minerals and rocks. It is an improvement upon the invention disclosed in my prior U.S. Pat. No. 3,257,080.

The invention of such prior patent has proven most effective in shattering and size reduction of solid material but the process therein disclosed does not provide the ideal environment for subjecting the material to shock phenomena throughout the entire system which connects the first zone with the second zone of said process. Also, the quick-opening valve that initiates the flow from the first to the second zone is located near the lower end of the vessel forming said first zone; such location, coupled with the fact that the working fluid is introduced into the first zone at a point above its lower end, results in the material being forced into and contacting the valve while said valve is still in the closed position, thereby subjecting the valve to serious abrasive forces and undue wear as the valve is operated.

The present invention improves the shattering process, minimizes valve wear and provides a more economical and reliable process and apparatus.

SUMMARY OF THE INVENTION The method comprises charging a pressure vessel which forms a first zone with a solid material of a selected particle size range, and introducing into said first zone a compressible working fluid until a desired pressure level is reached. The compressible working fluid is then permitted to expand as it is discharged into a duct from the first zone, thereby causing a portion of the working fluids enthalpy to be converted to kinetic energy and causing the entrainment of the solid material in the expanding fluid and accelerating it through the length of said duct, after which the mixed stream of fluid and solids is discharged into a second vessel forming a second zone. The method involves subjecting the solid material to shock phenomena as it exits from the first zone, subjecting it to further shock phenomena as it flows through the duct and to additional shock as it passes from the duct to the second zone; said method also accelerates the material as it flows through and exits from the duct, thereby inducing impact forces which further increase the shattering action and size reduction of the solids.

The method also subjects the accelerated mixed stream of fluid and solid particles to comminutive forces initially during flow through the duct by reason of interparticle collision and other forces and subsequently upon discharge into the second vessel forming the second zone, either by directing the material against a fixed impact surface in said second zone or by employing a dual system in impacting the high velocity stream of fluid and solid material from one system against the high velocity stream of fluid and solid material of the other system; such collision occuring in a common second zone and providing additional forces acting upon the material to effect further shattering and size reduction. Since impact occurs in said second vessel, it is sometimes hereinafter referred to as an impact chamber.

The apparatus includes means in the region of the connection between the first zone and the duct and in the region of the connection between the duct and second zone for creating shock phenomena to produce increased shattering and size reduction in these areas. A quick-opening valve is located in the duct between the first and second zones, and the working fluid which is accumulated in the first zone is principally introduced between this valve and said first zone. Such point of working fluid introduction ensures that the duct is free of solid material prior to the opening of the valve, and this, together with the location of the quick-opening valve a sufficient distance downstream of the first zone. assures that the valve will have time to move to the fully open position so that no solid material can strike the valve element, thereby preventing appreciable valve wear, and prolonging the life of the valve. The opening of the valve allows rapid expansion of the working fluid which is necessary to the establishment of flow and production of shock phenomena.

The duct which connects the first and second vessels comprises a novel and unconventional nozzle and elongated throat system which can be termed a supersonic nozzle arrangement for mixed streams consisting of solids and fluids. Preferably, such system comprises a convergent nozzle section extending from the first vessel or zone, an elongated throat section formed by a substantially constant diameter duct and a divergent nozzle section connecting said duct to the second vessel or zone. As will be hereinafter explained, the nozzle, and elongated throat, system produces greatly improved results in the size reduction of material.

OBJECTS OF THE INVENTION The primary object of the invention is to provide a method of shattering shock-severable solid materials, by adding a compressible working fluid to a charge of said solids, in a first zone, causing the solids to be entrained in the expanding working fluid through a nozzle, and elongated throat, system into a second lower pressure zone, and subjecting the material to shock phenomena throughout said nozzle, and elongated throat, system that connects the two zones, to produce effective shattering and size reduction of said material.

Another object is to provide an apparatus, of the character described, including a first vessel, a second vessel, a duct between the vessels to permit the material entrained in the working fluid to flow from the first to the second vessel, and a convergent nozzle connecting the first vessel and the duct; said nozzle having a configuration which will permit rapid expansion and acceleration of the working fluid to high velocity so that the fluid passing around entrained particles of the solid material will cause local zones of supersonic flow and create shock phenomena to which the particles will be subjected, thereby effecting shattering and size reduction of said particles.

A further object is to provide an apparatus, of the character described, wherein a high percentage of the working fluid for entraining the material to be shat tered in introduced into the duct at a point between the first vessel and a quick-opening valve so that that portion of the duct between said first vessel and said quickopening valve is swept clear of solid material; said valve being located a sufficient distance downstream of said first vessel to permit the valve to reach the full open position before any material flowing from the first vessel through the duct reaches said valve, thereby obviating any significant abrasion or wear of the valve.

A further object is to provide a shattering system which produces high velocity streams of solid material which are jetted into an impact chamber or zone; said system lending itself to use in an arrangement wherein one high velocity stream of material may be impacted against another high velocity stream of material, whereby the impact forces so generated are utilized to increase the shattering effect and the size reduction of the solid material.

A further object is to provide an apparatus, of the character described, wherein the shape of the second vessel is designed so that it converts the three dimensional flow of the mixed stream of working fluid and solids entering said vessel into a one-dimensional or linimpact chamber are connected by means of a system comprising a convergent section, an elongated throat section, and a divergent section, the throat section being adapted to produce choked and sonic flow of the mixed stream of fluid and solid particles at the entrance to said divergent section, which flow is then accelerated to supersonic velocity as it discharges through the divergent nozzle section to create additional shock effects which act destructively on the solids in the jet entering said impact chamber.

A further object is to provide a pressure vessel so designed that complete discharge of the solid materials is achieved.

A particular object of the invention is to provide nozzles which function as supersonic nozzles for a mixed stream consisting of solid particles entrained in a working fluid, such as steam or the like.

Other objects, features and advantages of this invention will be apparent from the drawings, the specification and the claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of the apparatus used to perform the method of the present invention.

FIG. 2 is an enlarged view of the duct which connects DESCRIPTION OF FIRST EMBODIMENT OF INVENTION In the drawings the letten A designates a first vessel or zone which is connected through a special system formed by a duct B with a second zone C. Flow through the duct B is initiated by a quick-opening valve D. A convergent nozzle section E connects the outlet of the first zone A with a duct B, while the other end of the duct has connection with the second zone C through a divergent nozzle section F. The duct B forms an elongated throat section which extends between the con vergent and divergent sections. The convergent section E, throat section B and the divergent section F provide a novel nozzle, and elongated throat, system and form the connecting duct B between vessels A and C.

Zone A is adapted to receive the solid material which is to be reduced in size. A compressible working fluid, such as steam, is introduced into zone A through an inlet line G having communication with the throat section B between valve D and convergent nozzle E. During the introduction of the working fluid, the valve D is in the closed position. Introduction of the working fluid-into zone A is continued until a preselected pressure is reached whereby thermal energy or enthalpy is stored within said zone; the preselected pressure and the ratio of fluid to solids are varied in accordance with the desired size reduction to be accomplished of the particular material being processed.

The term compressible working fluid as used herein, includes not only steam but any gas or vapor which is capable of doing useful work upon expansion. The term solids is used herein interchangeably with the terms solid particles, solid material and solid substance, and refers to the material being processed. As used herein, the term severance is employed in the sense stated at pages 1-01 and 1-03 of A. F. Taggarts Handbook of Mineral Dressing (1945), i.e., severance signifies a comminution or breaking apart of I a solid substance. Shock-severable refers to a solid fer of kinetic energy out of the working fluid and into the solid particles so that the particles are accelerated to a high velocity by the time they enter the divergent nozzle-section F; During flow through the duct, the solid particles are subjected ,to additional shock phenomena. In..the divergent nozzle section, the mixed stream of fluid and solid particles is accelerated to supersonic flow which subjects said particles tofurther shock phenomena. Thereafter the combined fluid and solids stream is directed into the second zone C.

The area of the discharge from the second zone C is sufficiently large so that there will be no back pressure condition or effect created in this zone which would be adverse to the efficient production .of the kinetic energy of themixedstream as' it. is discharged into this zone.

From zone C the mixed stream is discharged through a divergent passage H which communicates tangentially with a cyclone separator I. This passage is made divergent in order to decelerate the flow into said cyclone separator. The working fluid is preferably withdrawn from the separator I from the upper end, although said fluid or a portion thereof may be withdrawn from the lower end at a low velocity. The solid material is withdrawn from the lower end of the separa tor.

The apparatus employed in carrying out this improved method includes a pressure vessel which defines a zone A. A solid material loading valve 11 and a loading hopper 12 are located at the upper end of said vessel. The loading valve may be actuated by any suitable valve actuator lla, and said actuator may be operated by pneumatic or other means. The cross-sectional area of the lower end of the vessel 10 is reduced, as generally indicated at 13, and has an eccentric outlet 14 which connects with the larger end of the convergent nozzle section E. The smaller end of said nozzle section is coaxial with the throat section B which is terminated by the nozzle section F and the Coanda surface 21.

The material to be processed is delivered to the feed hopper 12 after having been previously prepared to provide a suitable charge. When the valve 11 is opened, the material enters the vessel 10 which defines zone A. The size of the vessel 10 is subject to wide variation and depends on the scale of operation.

After the desired amount of the solid substance or material has been introduced into the charge zone A, the working fluid, which will be referred to herein as steam, is introduced from a supply line 15, through a control valve 16 and into the inlet line G. A pair of inlet ports 16a and 16b connect with the inlet line G and extend through the duct B, preferably in diametrically opposed relationship for the purpose of introducing the working fluid into duct B. The use of opposed inlet ports is desirable because a single inlet might cause the high-velocity steam to eventually crater or wire-draw the metal of the opposite side of the duct. The inlet ports 16a and 16b communicate with the duct B between the quick-opening valve D and the convergent nozzle section E so that the working fluid is introduced through duct B and flows through the duct in a direction toward the vessel 10 by reason of the valve D being in the closed position at this time. By injecting the working fluid in this manner, the line B is swept clear of solid particles and the working fluid is introduced into the lower end of vessel 10 so as to create a spouted bed in vessel 10. The introduction of the working fluid into the lower end of the vessel also effects a transfer of any relatively fine material to the upper portion of said bed. By reverse classification the jamming of fine material into the discharge zone is obviated.

In actual practice of the invention, a wide range of solids/fluid weight ratios may be employed. For example, with saturated steam at 450 psi, the range may vary anywhere up to approximately 200 to l. The solids/fluid ratio is determined by the extent to which the vessel 10 is filled with material to be processed and by the quantity of working fluid which is introduced. The pressure of the fluid which is introduced into vessel 10 is also subject to variation over a wide range, usually in the range of from 50 to 2,000 psia. The pressure chosen depends upon the material being processed and the degree of shattering which is desired.

The valve D is illustrated as a rotary type valve which has its shaft 17 connected to a suitable valve actuator 18. The valve is full-ported, that is, when the valve is in its open position, the port or opening therethrough is identical to the size and shape of the bore of the duct B. As previously noted, the valve is quick opening so that after the material has been pressurized in the first zone A, said valve opens substantially instantaneously to initiate the flow of the mixed stream of fluid and solids.

One of the important features of the present invention is the location of the valve D downstream from the zone A a sufficient distance so that the valve will be fully open before any of the particles of solid material reach the body of the valve. Actual use of this invention has shown that unless an arrangement is provided to so protect the valve, the force of the solids moving at high velocity through the duct B and against the closure member of the valve abrades and damages the valve very quickly. This valve may be located at any point along the axis of the system as long as the criteria set forth in the preceding sentences are satisfied. In the present instance, the rapid opening of the valve, coupled with the location of the valve well downstream from vessel 10, assures that the valve will be fully open prior to the time that any solid particles reach or pass through it. This advantage is enhanced by the fact that the working fluid is introduced through the duct B in a direction opposite to the direction of discharge of the material from the vessel 10; such introduction of the working fluid at this point sweeps the duct free of solid material. Therefore, when the valve is subsequently opened and flow is initiated, the material must travel from the vessel 10 to the valve, thereby providing sufficient time for the valve to move to the fully open position before the solid particles reach the same. In actual practice, it has been found that satisfactory results are obtained if the valve is opened in less than 20 milliseconds when this valve is positioned about 4 feet downstream.

Upon the valve D being opened, the mixed stream passing from the vessel 10 flows through the convergent nozzle section and into the throat section B. As the mixed stream passes through the convergent nozzle section E, said nozzle section B permits acceleration of the working fluid to a high velocity, which is to say that it converts a portion of the enthalpy of the said working fluid to kinetic energy in accordance with the physical laws governing isentropic flow. The entrained solids are accelerated initially only slightly, whereas the fluid attains its maximum velocity at the exit of this convergent nozzle section. The high fluid velocity, relative to the solids velocity, causes local zones of supersonic flow to arise on the irregular solid surfaces. Since these local zones of supersonic flow are highly perturbed, shock waves of great force are generated in these thin zones; because the supersonic zones are attached, the shocks are also attached to the solids, whereby said solids are subjected to this shock phenomena as they flow through the nozzle.

As an example of the relative velocities at the exit of convergent nozzle section E into the throat section B the fluid velocity is on the order of 1100-1200 fps, while the solids velocity is less than 30 fps. Since the fluid velocity, relative to the solids velocity, is more than 1100 fps, corresponding to a Mach Number of 0.65 to 0.75, the shock waves referred to above are generated on the surfaces of the solid particles. As

noted, since the shocks arise on the irregular solid sur-' faces, the shocks are attached to the solid surfaces, and are propagated through the solids, causing failure or rupture along planes of discontinuity. Even small increments of shock energy are effective because of accumulated fatigue that results in failure of interfacial bonds when the total accumulated shock energy exceeds the bond energy.

The convergent nozzle section E is subject to considerable variation as to its shape, including its size and length; in actual practice, it has been found that it may have an area ratio of its large end to its small end of from 3 to l to 8 to 1, preferably about 4 to 1. Its design must provide for a smooth entry to the nozzle and a well rounded converging section discharging into throat section B. It is preferable that said nozzle be formed as an eccentric type nozzle, as shown in FIG. 2, so that the lower portion of the nozzle wall lies in the same plane as the lower wall portion of the vessel outlet 14 and the lower wall portion of the throat B, thereby assuring a smooth uninterrupted flow of the mixed stream from the lower end of vessel 10, through said nozzle section E and into said throat section B.

As the mixed stream travels through the throat section the solids are subjected to further shock phenomena due to the working fluid decelerating at a faster rate than the entrained solids accelerate and creating local zones of supersonic flow. During the entire travel of the mixed stream through the elongated throat section B the solids velocity increases and the fluid velocity decreases. In a throat section of optimum length the entire flow is at nearly uniform speed at the end of said throat. As the mixed stream enters divergent nozzle section F, the fluid is further accelerated in said divergent nozzle section and the solids are accelerated at the expense of most of the added kinetic energy obtained by the additional isentropic expansion of the fluid in the divergent nozzle. This expansion is adiabatic, in the sense that no heat is added. Since, at least theoretically, the system may be reversible, this will be treated as isentropic expansion. From the nozzle F, the stream is discharged into the second zone C which is formed by a volute shaped receiving vessel or chamber 19. The second zone is herein referred to as an impact chamber and may have an impact or target plate 20, as shown in dotted line's in FIG. 1, located therein in the path of the mixed stream which is discharging into the vessel.

The divergent nozzle section F is generally conical, although it may be parabolic, and its length and arearatio are dictated by the laws governing isentropic flow processes. Since fluid expansion, as such, can make little or no contribution to the effectiveness of the process, the divergent nozzle section is made as long as possible by restricting the half-angle of divergence to a preferable range of 4 to 7 and preferably about This provides a sufficient length and time of contact for kinetic equilibrium between the phases to be established or closely approached. The solids being now immersed in a supersonic fluid perturb the supersonic flow with resulting shocks arising on and around the solid particles, thus subjecting them to additional comminutive forces.

From the divergent nozzle section F, the mixed stream flows across the flared inlet or Coanda surface 21. Such Coanda surface diverts a significant portion of the fluid and the fine material in a direction approximately at a right angle to the major axis of the nozzle. The entire jetted stream is discharged into the volute shaped chamber 19 which forms the zone C. As stated, the impact or target plate 20 may be employed in the chamber C and has its face disposed in a plane normal to the axis of the duct B. It is spaced a sufficient distance from the nozzle F so that it will not interfere with flow of the mixed stream but is sufficiently close to assure that the central portion of the high velocity stream will impact against it. Thus, in addition to the other shock phenomena to which the particles are subjected, said-particles are subjected to impact forces which effect further size reduction. It is believed that as the material moves through the duct B, radial classification of the solid particles occurs with the larger particles tending to be concentrated at or near the center or axis and the smaller particles moving along the walls. By providing an impact plate which has its surface located so that the larger particles being ejected from said duct at a high velocity will strike the same, said particles are subjected to high impact forces. This causes additional fracturing or shattering by reason of elastic rebound of the particles and impingement of the particles against each other.

The fine material and the boundary layer which are being discharged from the throat section at high velocity tend to cling to the inner surface of nozzle F and to the Coanda surface 21, thereby diverting a portion of the working fluid and said fines outwardly from the axial direction as the jetted stream enters the vessel 19. The heavier solids collide with the plate 20, and with themselves.

By observing FIG. 3, which is a corss-sectional view of the volute shaped impact chamber 19, it will be evident that the jetted stream enters the chamber parallel to the axis of generation of the volute. The fluid and solids will move randomly after initial entry into the volute' chamber and some of the particles will strike the inner wall of said chamber to subject them to further impact. The volute shape of the vessel imparts a rotary motion to the fluid and comminuted solids so that said fluid and solids are directed to the outlet end 19a of said chamber in linear subsonic flow.

From the volute shaped vessel 19 which forms the impact or receiving zone C, the working fluid and comminuted solids move downwardly through the divergent passage H and into the cyclone separator I. Separation occurs with the solids being preferably discharged downwardly through a discharge pipe 24 and the working fluid being conducted upwardly through an outlet pipe 25.

In operation,-the ore or other material to be processed is introduced through the feed hopper 12, through the loading valve 11 and into the pressure vessel 10. After pressure vessel 10 is charged with the solid material, valve 11 is closed and working fluid inlet valve 16 opens to admit the working fluid through the line G into'throat B and then into the lower end of vessel 10. If desired, some portion of the working fluid may be introduced through an auxiliary line 15a which connects with the upper end of the vessel 10, with flow through said line being controlled by a valve 15b. The introduction of working -fluid is continued until the pressure within vessel-10 has "reached the desired operating pressure, whereuponvalves 16 and 15b close. It

is preferable that the introduction of steam be as fast as possible to minimize condensation.

The quick-opening valve D in the duct B is opened, either simultaneously with closing of valves 16 and 15b, or immediately thereafter, to connect between the lower end of zone A and the duct B. When valve D is first opened, the solid particles in the lower end of vessel 10 are substantially at rest while the working fluid immediately flows through the nozzle section B and into the throat section B'. In doing so, it flows around such particles at a high velocity. The relative velocity of the working fluid to the solid particles results in a transonic condition which may be defined as one wherein local zones of supersonic and sonic and subsonic flow occur together in the stream. The supersonic zones arise on the surfaces of the solid particles which are impinged by the flow of the working fluid. As is well known, shock waves always occur in these supersonic zones because the flow is densely populated with compression waves propagating downstream. The compression waves overtake each other to produce shock waves so that the solid material is subjected to shocks that arise in the supersonic zones that are attached to solid surfaces.

When shocks are transmitted into a solid and come to a discontinuity, such as crystal face, fracture plane or fatigue plane, half of the incident shock is reflected backward while the other half of the incident shock is transmitted forwardly through the material. The amplitude and velocities of the reflected and transmitted shocks depends on the nature of the solids on either side of the discontinuity. Incident shocks are partly reflected and partly transmitted from and through such discontinuities with the result that such interfaces are placed in tension. It is believed that the effectiveness of the shattering system herein disclosed is mostly likely due to the fact that typical shock-severable materials are far weaker in tension than they are in compression; when acted upon in the foregoing manner, solid particles are more readily shattered or reduced in size than when reduction is attempted by conventional crushing or milling. This not only produces a shattering but because the forces that separate the solids into individual crystals or grains are predominately tensional, there is very little tendency for the grains themselves to be fractured and there is little tendency for incomplete separation at crystal boundaries to occur. Therefore the process produces a clean and discrete separation of the grains of the material.

At the entry to the throat section B of duct B, the fluid velocity is at maximum whereas the solid material is just beginning to accelerate. As previously explained, this high relative velocity of the fluid to the solids results in transonic flow wherein local zones of supersonic, sonic and subsonic flow occur together. Supersonic zones arise on the surface of the solids and create shock waves that are attached to the particles and which propagate through the solids causing rupture at areas of discontinuity or fatigue.

By providing a throat section B of sufficient length and of substantially the same cross-sectional area throughout that length, kinetic energy is transferred from the fluid to the solids and the mixed stream attains a very high velocity. It is essential to acelerate the mixed stream to a very high velocity so that as it is ejected into the divergent nozzle section F, shock phenomena will occur on the solids in the nozzle F. Additionally, if an impact plate 20 is located in zone C, the high velocity impact will increase the size reduction.

The mixed stream leaves throat B at the sonic velocity of that particular type of stream. Therefore, the flow in the nozzle F, becomes supersonic and shock waves are created on the solids which subject the particles to further forces which reduce their size. As the stream moves through the nozzle, the fluid expands to its limit and is discharged at supersonic velocity into zone C.

If an impact plate 20 is employed in zone C, the larger particles in the mixed stream which tend to concentrate at or near the axis of the stream are forcibly impacted at high velocity against the plate. Such impact not only further breaks up or shatters the particles but also results in elastic rebound resulting in interparticle collision as the particles bounce back from the impact surface. This increase impingement of the larger particles against each other and effects additional size reduction. The volute shaped chamber 19 induces rotary motion of the fluid and comminuted material and directs them to the outlet 19a.

From the zone C the fluid and particles are conducted by means of the divergent passage H downwardly into the cyclone separator I. Within the cyclone, the particles are separated and discharged through a discharge line 24, while the working fluid escapes through an upper outlet 25.

As has been noted, this system has been proven to provide an effective supersonic nozzle for mixed streams consisting of solids and fluid. In further explanation of the operation of the invention, it is pointed out that after the pressure vessel A is loaded, the introduction of the working fluid into such vessel is continued until a preselected pressure is reached whereby a supply of thermal energy (enthalpy) is stored therein; the preselected pressure is varied in accordance with the desired ratio of fluid to solids, this ratio being the controlling parameter so far as the extent of size reduction is concerned. The pressure is a measure of the quantity of fluid in the pressure vessel; the enthalpy of the steam is the measure of its total energy per unit mass. The decrease in the enthalpy is the measure of the available work which can be done on the solid materials. The kinetic energy is equal to the reduction of the enthalpy; in terms of work the only energy of interest is kinetic energy.

The pressure chosen depends upon the desired or required solids/steam weight ratio; pressure, as such, is not a measure of the available energy. When the valve is opened, the mixed stream is subjected to shock phenomena in the convergent nozzle section B and is subjected to further shock phenomena as it travels through the duct B. At the entry to elongated throat B, the fluid velocity is at maximum, whereas the solids are just beginning to accelerate. However, during the entire travel of the mixed stream through the elongated throat section, the solids velocity increases and the fluid velocity decreases since the energy of the fluid is distributed or partitioned among the several mass components of the flow.

As illustrated, the divergent nozzle section F is generally conical, although it may be parabolic and its length and area-ratio are dictated by the laws governing isentropic flow processes. Since fluid expansion, as such, would make little or no contribution to the effectiveness of the process, the divergent nozzle section is made as long as possible by restricting the half-angle of divergence to the lower practical limit, which is about This provides a sufficient length and time of contact for kinetic equilibrium between the phases to be established or closely approached. The solids being immersed in a supersonic fluid perturb the supersonic flow with resulting shocks arising on and around the solid particles, thus subjecting them to additional comminutive forces.

The mixed stream leaves the throat section B at sonic velocity for that particular system. The speed of sound in the mixed fluid is not the same as in the fluid alone. For any particular fluid such as stream or air, the sonic speed is given by: a ['yg RT] where g 32. I 74; 'y= ratio of specific heats; R specific gas constant; and T is the stream temperature in degrees R. Knowing the initial or stagnation temperature T,,, we can write:

In a two-phase system, we can write:

where r is the solids/fluid weight ratio. Therefore, the flow in the divergent nozzle section F becomes supersonic and shock waves are created which subject the particles to further forces which reduce their size. As the stream moves through the nozzle, the fluid expands further and is discharged at supersonic velocity into the impact chamber C.

Upon leaving the divergent nozzle section F, the stream flows across the Coanda surface which, as has been explained, hsa the function of diverting the boundary layer and, by over-expansion, decelerating the flow through shock to low subsonic velocity. The boundary layer contains a large population of the very small particles created in the system without the forces of terminal impact having been applied. The high rate of deceleration protects the fines from further or excessive comminution.

In connection with the impact which occurs within the impact chamber, the particles at the center of the stream are subjected to high terminal impact forces. Additional fracturing or shattering occurs by reason of elastic rebound of the particles and impingement of these by oncoming solids in the stream. A large stagnation pressure results when a high velocity jet is brought to rest, all of the kinetic energy being converted back to enthalpy. In other words, the fluid, when stagnated, approaches its initial state. The stagnation temperature is higher than the supply temperature, the enthalpy is equal and the pressure is less because of dissipative effects such as friction and work done externally, i.e., such as the rupturing of interfaces between crystals.

Although it is believed that the size reduction and comminution of the solids is caused primarily by reason of subjecting the solids to shock phenomena throughout the system, some assistance may be obtained by reason of thermal shock. Where steam is employed as the working fluid, heat is conducted into the material and as the process progresses, the utilization of some of this heat in expanding the surface layers of the particles may be a cause of incipient failure or fracture.

SECOND FORM OF THE INVENTION vergent nozzle F. The second system identified by'the Roman numeral Il includes the same elementsfA, B, D,

E and F. The dual system utilizes a commonj'receivin zone or impact chamber which is identified-by the let ter C. Y v

Systems I and II have their respective nozzle section F communicating with said common impactjc-hatiber 7 zone C. The zone C is formed by a volute shapedves se] 1% similar in design to the chamber l9, excjept' that it provides for connection of the two nozzle sections F in opposed relation on opposite sides of the volute.

Within the interior of chamber 19b, there are located two deflector plates 26 and 27 (FIGVS) which are located in spaced relation to each other and are also located in spaced relation to the end of thenozzles F. Each plate is provided with a central opening 28' which may have an annular insert 29 of hardened material mounted therein. The deflector plates'26 and 27 have their openings 28 axially aligned with the axis of their respective nozzles F which discharge into the zone C.

The plates are close enough to the ends of the nozzles to assure that the central portion of each jetted stream passes through openings 28 and collides with the opposing jetted stream. The spacing between the plates is not critical but they should be far enough apart to permit free flow of material from between the plates after collision has occurred.

As has been noted, the travel of the solids through each duct B at a high velocity classifies such solidsfradially so that the major portion of the larger particles are concentrated in or near the axis or central part of each duct. As explained, the finer material-and a portion of the fluid which together comprise theboundarylayer tends to cling to the Coanda surfaces 21 and is diverted radially outwardly. With proper location of the ends of the deflector plates 26 and 27 relative to nozzles-F, the central portion of each jetted stream will pass through the opening 29 of its deflector plateand collide with the other jetted stream. Since the streams are travelling at a high velocity as they enter the zone C, it will be seen that the collision between the two central portions of the streams will perform a large amount of additional work in reducing the size of the particles. The deflector plates also function to deflect the smaller particles which strike the plates in a direction radially outwardly of the axis thereof.

As described herein, the systems employ a fastoperating, quick-opening valve in the duct which connects the first zone to the second zone. It is important that there be a sudden opening of the duct and although the valve is preferable, it is evident that other devices, such as a burst diaphragm could be employed. Where a burst diaphragm is used, the diaphragm would be constructed to withstand a preselected pressure which would be the pressure to which the material is subjected in the first zone; upon such preselected pressure being reached, the diaphragm would rupture to suddenly open the duct and permit flow therethrough, as hereinbefore described.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof and various changes in the size, shape and material, as well as in the details of the illustrated construction, may be made with the scope of the appended claims without departing from the spirit of the invention. To illustrate relative sizes of operative embodiments, however, the following are examples of prototype units constructed according to the teachings of this application.

The prototype units include four pressure chamber sizes: 0.05, 0.49, 2.23, and 6.50 cubic feet. They also include three nozzle system sizes, having nominal throat internal diameters of 1, 2, and 4 inches, respectively. The relevant dimensions of each nozzle system are given in the table below:

The largest size of feed that can be handled by each system depends in part on the type of material and its shape (whether oblong or of relatively uniform dimensions). Best results in the one-inch system have been obtained with materials passing a A-inch mesh screen. Best results in the four-inch system have been obtained with materials passing a l /z-inch screen, although materials having dimensions up to 2 inches have been tested.

What is claimed is:

1. An apparatus for reducing the size of shockseverable material comprising,

a first vessel for receiving the material and defining a first zone,

a second vessel defining a second zone,

a duct extending from the first vessel to the second vessel,

a quick-opening valve in said duct,

means for introducing a predetermined amount of a compressible working fluid into the first vessel including an inlet in said duct adjacent to said valve for introducing at least a substantial portion of said predetermined amount for carrying any of said material in the duct back to the first vessel.

means for closing said valve during the introduction of said fluid into the first zone,

means for opening the valve suddenly to discharge a mixed stream of working fluid and material from said first vessel into the duct, which conducts said stream to the second vessel,

means located between the first vessel and duct for creating a zone wherein the solid material is subjected to shock phenomena as it exits from the first vessel and enters said duct to thereby shatter and reduce the size of said material,

said quick-opening valve being located a predetermined distance from the first vessel, and

the spacing of the valve from said first vessel and the time of opening said valve being such that said valve moves to fully open position before the material discharged from said first vessel reaches said valve.

2. The method of reducing the size of shockseverable solids comprising,

introducing a charge of said solids into a pressure vessel,

introducing a compressible working fluid into the pressure vessel until a preselected pressure is attained in said vessel,

directing a mixed stream of the working fluid and solids into a continuous nozzle system which extends from said pressure vessel to an impact chamber through the successive steps of converging the mixed stream in a converging section of the nozzle system, thereby accelerating the working fluid portion of the mixed stream relative to the solids,

directing the mixed stream through an elongated throat section of the nozzle system having a constant area equal to the minimum area of the converging section and a length sufficient to accelerate the solids of the mixed stream relative to the working fluid portion until maximum kinetic energy has been transferred from the working fluid to the solids and the stream reaches the sonic velocity of the fluid-solids mixture;

diverging the mixed stream approximately isentropically at supersonic velocities in a diverging section of the nozzle system and discharging the mixed stream of working fluid and solids as a free jet into the impact chamber after passage through the nozzle system, the pressure in the impact chamber remaining approximately constant.

3. The method set forth in claim 2, with the additional step of impacting the solids in the free jet against a rigid surface within the impact chamber.

4. The method set forth in claim 2 further comprising the step of separating the lighter solids and boundary layer of fluid from the central portion of the mixed stream discharging as a free jet into the impact chamber by flow over a Coanda surface connected to the downstream end of the diverging section of the nozzle system.

5. The method set forth in claim 2, further comprising the step of directing the mixed stream of working fluid and solids from the pressure vessel into the nozzle system through an eccentric lower end of said pressure vessel.

6. The method set forth in claim 2 comprising the further step of discharging the mixed stream of fluid and solids from the impact chamber into a cyclone separator through a divergent passage to decelerate the flow.

7. The method set forth in claim 2, wherein at least a substantial portion of the total working fluid introduced into the pressure vessel is introduced through an inlet into the nozzle system downstream from the converging section.

8. The method of reducing the size of shockseverable solids comprising,

introducing a charge of said solids into a pressure vessel,

introducing a compressible working fluid into the pressure vessel until a preselected pressure is attained in said vessel,

releasing a mixed stream of working fluid and entrained solids from said vessel into a nozzle system which extends from said pressure vessel to a chamber, said nozzle system comprising successively a converging section, an elongated throat section and a diverging section,

said system functioning to rapidly accelerate the working fluid and less rapidly accelerate said entrained solids to create shock phenomena as the working fluid and solids pass through the converging section,

said elongated throat section having a length suffrcient for the fluid to transfer maximum kinetic energy to the solids entrained therein and to accelerate the solids to the sonic velocity of the mixture as the mixed stream of fluid and solids flows through the elongated throat section,

said system functioning to further accelerate the fluid and solids as the mixture flows through the diverging section, and

discharging the mixed stream of fluid and solids as a free jet into a chamber after passage through the nozzle system for subjecting the material to further shock phenomena. 9. The method set forth in claim 8 comprising the additional step of impacting the solids against a rigid surface within the chamber.

10. The method set forth in claim 8 further comprising the step of separating the lighter solids and boundary layer of fluid from the central portion of the mixed stream discharging as a free jet into the chamber by flow over a Coanda surface connected to the terminus of the diverging section of the nozzle system.

11. The method set forth in claim 8 further comprising the step of discharging the mixed stream of working fluid and solids into the nozzle system from the pressure vessel through an eccentric lower end of said pressure vessel.

12. The method set forth in claim 8 comprising the further step of discharging the mixed stream of fluid and solids from the chamber into a cyclone separator through a divergent passage to decelerate the flow.

13. The method set forth in claim 8, wherein at least a substantial portion of the working fluid introduced into the pressure vessel is introduced through an inlet into the nozzle system downstream from the converging section.

14. The method of reducing the size ofparticles of a shock-severable solid material charged into a pressure vessel comprising,

adding to the solid particles a predetermined quantity of a compressible working fluid in the pressure vessel until a predetermined pressure is attained suddenly expanding a stream of the working fluid and solids from said vessel into a continuous nozzle system which extends from the pressure vessel to a chamber so that the particles of solid material are entrained in the fluid stream, said nozzle system comprising a converging section, an elongated throat section and a diverging section,

directing the stream from the pressure vessel through said converging section of the nozzle system for increasing the velocity of the working fluid to a maximum value at the entrance to the elongated throat section to generate shock waves which act upon the particles of said material to reduce their size,

directing the mixed fluid and solid stream through said elongated throat section until maximum possible transfer of kinetic energy from the fluid to the solid particles has been achieved, the velocity of the combined polyphase fluid and solid mixture attaining the sonic velocity of said mixture at the downstream end of the throat section, and

directing the mixed stream through the section into a chamber for accelerating the fluid and the solid particles in themixed stream to supersonic velocities said chamber having a sufficiently large exit area to permit free expansion of said fluid with minimal stagnation pressure in said chamber.

15. The method set forth in claim 14 wherein the elongated throat section has a substantially constant cross-sectional area.

16. The method of reducing the size of particles of a shock-severable solid material comprising,

entraining said particles in a stream of compressible working fluid,

accelerating said fluid at a faster rate than said particles within a converging boundary surface, then further accelerating said particles and decelerating said fluid within an elongated continuation of said boundary surface having substantially constant cross section until maximum transfer of kinetic energy from the fluid to the solid particles has been achieved and the velocities of the particles and fluid are substantially equal to the two-phase sonic velocity of said mixed stream, I

then still further accelerating said fluid and said particles to supersonic velocities in a diverging continuation of said boundary surface, and l discharging said particles and fluid into a chamber,

whereby said particles will be subject to shock phenomena at each stage of acceleration of said particles. 17. The method of reducing the size of shockseverable solids comprising,

introducing a charge of said solids into a first pressure vessel,

introducing a compressible working fluid of predetermined quantity'and pressure into the pressure vessel,

directing a mixed stream of fluid and solids into a first nozzle system which extends from said pressure vessel to an impact chamber maintained at approximately said second pressure, said first nozzle system comprising a converging section, an elongated throat section and a diverging section, the length of the throat section being sufficient to permit maximum transfer of kinetic energy from the fluid to the solids so that the velocities of said fluid and solids equal the sonic velocity in the mixed stream at the downstearn end of the throat section, subjecting the stream to shock phenomena as it flows from the pressure vessel to the impact chamber, discharging said stream asa free jet into said impact chamber at a high velocity, introducing a charge of said solids into a second pressure vessel, 7 introducing a compressible working fluid of predetermined quantity and pressure into the second pressure vessel, directing a mixed stre arn of fluid and solids into a second nozzle system which extends from said second pressure vessel to the impact chamber,

said second system comprising a converging section,

an elongated non-divergent throat section and a diverging section, the length of the throat section being sufficient to permit maximum transfer of kinetic energy from the fluid to the solids so that the velocities of said fluid and solids equal the sonic velocity in the mixed stream at the downstream end of the throat section,

subjecting the stream to shock phenomena as it expands at supersonic velocity through the diverging section to the impact chamber,

discharging said stream as a free jet into said impact chamber at a high velocity,

and selectively impacting the coarser portion of the solids discharging from the first system against a similar portion of the solids discharging from the second system to further reduce the size of the solids.

18. The method set forth in claim 17, with the additional step of deflecting the finer portion of the solids and the boundary portion of the working fluid discharging as free jets from the diverging sections of the nozzle systems radially outwardly and away from the impact zone by means of Coanda surfaces. 19. The method set forth in claim 17, wherein said solids are subjected to said shock phenomena as they pass through said nozzle systems by directing said solids through said converging sections which direct the flow from the pressure vessels into the elongated throat sections, and

said solids are subjected to further shock phenomena in the region of the exits from the systems by directing said solids through said diverging sections which direct the flow from said throat sections into the impact chamber.

20. The method of claim 17, wherein the impact chamber has a sufficiently large exit area to permit free egress of said fluid, with no general increase of the pressure in said chamber.

21. An apparatus for reducing the size of particles of a shock-severable solid material comprising,

a pressure vessel for receiving the particles,

an impact chamber,

a system extending from the pressure vessel to the impact chamber,

said system comprising a convergent nozzle section,

an elongated throat section and a divergent nozzle section opening into the impact chamber,

a quick-opening valve in said system,

means for introducing a predetermined amount of a compressible working fluid into the pressure vessel when the valve is closed that is sufficient to create sonic flow at the downstream end of the elongated throat section of a mixed stream of working fluid and particles of material when the valve is opened, the length of the elongated throat section being sufficient to permit maximum transfer of kinetic energy from the fluid to the particles of solid material in the mixed stream, and

means for opening the valve to suddenly discharge a mixed stream of working fluid and particles of solid material from said vessel through the system wherein shock phenomena act to shatter and reduce the size of said material.

22. An apparatus as set forth in claim 21 comprising a discharge passage from the pressure vessel eccentric to the principal axis of said vessel connecting the pressure vessel to the larger end of the convergent nozzle section.

23. An apparatus as set forth in claim 21, wherein the valve is positioned in the elongated throat section and the means for introducing a compressible working fluid into the pressure vessel comprises an inlet duct connected into the system between the valve and the convergent nozzle section.

24. An apparatus as set forth in claim 23, wherein the means for introducing a compressible working fluid comprises two ducts entering said system in opposed relationship.

25. An apparatus as set forth in claim 21 further comprising a Coanda surface forming a smoothly flaring connection between the outlet of the divergent nozzle section and the impact chamber.

26. An apparatus as set forth in claim 21 further comprising a separator and a divergent passage connecting the impact chamber to the separator for decelerating the fluid passing from the impact chamber to the separator.

27. An apparatus as set forth in claim 21, wherein said convergent nozzle section has its larger end connected with the pressure vessel and its smaller end connected with the throat section, the length and configuration of the convergent nozzle section being such that after introducing said predetermined amount of compressible fluid into the pressure vessel and upon opening of the valve, the working fluid expands to attain a velocity sufficient to cause local zones of supersonic flow attached to the slower moving solid particles whereby the solids are subjected to shock phenomena resulting from the perturbation of said local zones of supersonic flow.

28. An apparatus as set forth in claim 21, wherein said elongated throat section is of substantially constant cross-sectional area throughout its length, and

the divergent nozzle section connects the throat sec- 40 tion with the impact chamber and is constructed to further increase the velocity of the stream as the mixed stream is discharged into the impact chamber.

29. An apparatus for reducing the size of shockseverable solids comprising,

a convergent nozzle section,

an elongated throat section of constant area having one end connected to the smaller end of the convergent section, a divergent nozzle section having its smaller end connected to the other end of the throat section, and

means for supplying a subsonic stream of said solids entrained in a compressible working fluid to the larger end of said convergent nozzle section for flow through said sections, the pressure of said working fluid at the entrance of the convergent nozzle section being sufficient to accelerate the mixture to attain sonic velocity at the downstream end of the throat section, the throat section being long enough to assure maximum transfer of kinetic energy from the fluid to the solids, and the divergent nozzle section being constructed to accelerate the mixed stream to supersonic velocities.

30. An apparatus for reducing the size of a shockseverable material comprising,

a pressure vessel for receiving the material,

an impact chamber,

a system extending from the pressure vessel to the impact chamber,

a quick-opening valve in said system,

means for introducing a compressible working fluid into the pressure vessel,

said valve being in closed position during the introduction of said fluid into the pressure vessel,

means for opening the valve to suddenly discharge the mixed stream of working fluid and material into the system which conducts said stream to the impact chamber,

means located in the system downstream of the pressure vessel adapted to subject the solid material to shock phenomena to thereby shatter and reduce the size of said material,

said quick-opening valve being located a predetermined distance from the pressure vessel,

the compressible working fluid being introduced into the system between said valve and said pressure vessel, whereby such working fluid flows into the vessel through the system in a direction opposite to that in which the material is discharged from said vessel, and

the spacing of the valve frorm said pressure vessel and the time of opening of said valve being such that said valve moves to fully open position before any of the material discharged from said pressure vessel reaches said valve.

31. An apparatus for reducing the size of particles of shock-severable solid material comprising,

first and second pressure vessels for receiving the particles of material,

an impact chamber positioned between the pressure vessels,

a separate nozzle system extending from each pressure vessel to the impact chamber with the axis of one system intersecting the axis of the other system in the impact chamber,

each system comprising in continuous succession a converging section, an elongated constant area throat section and a diverging section,

a quick-opening valve in each of said systems,

means for introducing a compressible working fluid into each of said vessels while said valves are closed, and

means for simultaneously opening the valves to suddenly discharge mixed streams of working fluid and material from each of the pressure vessels through the respective systems into the impact chamber from opposing directions, the pressure of said working fluid at the entrance of the convergent nozzle section being sufficient to accelerate the mixture to attain sonic velocity at the downstream end of the throat section, the throat section being long enough to assure maximum transfer of kinetic energy from the fluid to the particles of solid material, and the divergent nozzle section being constructed to accelerate the mixed stream to supersonic velocities for discharge as a free jet into the impact chamber,

whereby shock phenomena shatter and reduce the size of said particles in the nozzle systems and further reduction of the size of the particles is caused by collision of the interseting streams of particles discharged from the two nozzle systems in the impact chamber.

32. An apparatus as set forth in cliam 31 further comprising discharge passages from the pressure vessels to the respective nozzle systems that are eccentric to the principal axis of each of said vessels.

33. An apparatus as set forth in claim 31, wherein the quick-opening valves are positioned in the elongated throat sections of each system and the means for introducing a compressible working fluid into the pressure vessels is comprised of inlet ducts opening into the systems between the valves and the convergent nozzle sections.

34. An apparatus as set forth in claim 33, wherein said fluid inlet ducts comprise at least two ducts opening into each nozzle system in opposed relationship to reduce erosion from wire-drawing by the incoming fluid.

35. An apparatus as set forth in claim 31 further comprising Coanda surfaces between the ends of the divergent nozzle sections and the impact chamber.

36. An apparatus as set forth in claim 31 further comprising a separator and a divergent passage connecting the impact chamber to the separator for decelerating the fluiid and solid particles passing from the impact chamber to the separator.

37. An apparatus as set forth in claim 31 further comprising two deflector plates spaced from the discharge end of each nozzle system and located in said impact chamber, each deflector plate having a central opening so that the particles in the central portion of one discharged jet may collide with the particles in the central portion of the other jet while the remainder of each jet is deflected away from the collision region.

38. A method of reducing the size of shock severable solids comprising the steps of:

entraining particles of said solids in a stream of compressible working fluid surrounded by a cylindrical boundary surface;

directing the mixed stream of fluid and solid particles through a converging boundary surface, thereby accelerating the fluid at a faster rate than the solids;

then directing the mixed stream in a straight line through an elongated cylindrical boundary surface equal in cross section to the downstream end of the converging boundary surface until maximum transfer of kinetic energy from the fluid to the solid particles has been achieved and the velocities of the particles and fluid are substantially equal to the two-phase sonic velocity of said mixed stream, and discharging said particles and fluid into a chamber.

39. An apparatus for reducing the size of shockseverable solids comprising:

a converging nozzle section,

an elongated throat section of constant area extending in a straight line from the smaller end of the converging nozzle section, and

means for supplying a subsonic stream of said solids entrained in a compressible working fluid to the larger end of said converging nozzle section for flow through said sections, the pressure of said working fluid at the entrance to the converging nozzle section being sufficient to accelerate the mixture to attain sonic velocity at the downstream end of the throat section, the throat section being long enough to assure maximum transfer of kinetic energy from the fluid to the solids.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4089472 *Apr 25, 1977May 16, 1978Eastman Kodak CompanyImpact target for fluid energy mills
US4539010 *Dec 23, 1983Sep 3, 1985Australia LimitedCoal preparation
US5544820 *Feb 21, 1995Aug 13, 1996Walters; Jerry W.Clear-trajectory rotary-driven impact comminuter
US5829692 *Jan 17, 1997Nov 3, 1998Wildcat Services Inc.Modularly tiered clear-trajectory impact comminuter and modular comminution chamber
US5887809 *Apr 11, 1997Mar 30, 1999Wildcat Services Inc.Clear-trajectory rotary-driven impact comminuter
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US8202399Feb 10, 2009Jun 19, 2012David Walker TaylorProcess for modifying fuel solids
US8298306Feb 10, 2009Oct 30, 2012David Walker TaylorProcess for improved gasification of fuel solids
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Classifications
U.S. Classification241/5, 241/40
International ClassificationB02C19/06
Cooperative ClassificationB02C19/066
European ClassificationB02C19/06H