THE KINETIC EXTRUDER:A DRY PULVERIZED SOLID MATERIAL PUMP

Abstract: Method and apparatus are shown for the continuous feeding of pulverized material to a high pressure container. A rotor (1) is located within the high pressure container (2). The pulverized material is fed from a feed hopper (4) through a stationary feed pipe (3) to a vented spin-up chamber (8) to a plurality of two-stage sprues (9) mounted in the rotor. Control orifices (17) downstream from the sprues meter the flow of coal through the sprues. Previous feeders tried to keep the material in a fluidized state and avoid a compacted plug form of flow. The prevent feeder makes use of compacted plug formations in the sprues as seals against high pressure gas.

Description: - 1 - THE KINETIC EXTRUDER: A DRY PULVERIZED SOLID MATERIAL PUMP 1 2 3 4 5 . 6 7 8 Technical Field 9 A number of industrial processes involving vessels which operate 0 at elevated gas pressures require that solid material involved in the 1 process be fed tα them from a low or atmospheric pressure environment. 2 One such industrial process, coal gasification, requires the feeding of 3 pulverized or powdered coal to the elevated pressure reactor vessel from an atmospheric pressure hnpper αr the like. There are many types 5 of coal gasification processes, utilizing a wide range of reactor pres- sure levels. The present invention is capable of continuously feeding pulverized coal from a one atmosphere, environment to a 5 to 100 atmα- sphere environment. Background Art The prior art in current use in this area is either the slurry feed method or the batch process feed method (commonly known as the Iockhopper method). In the slurry feed method, a liquid-solid mixture is pumped into the pressure vessel using more or less conventional pumps. With this arrangement the liquid (usually water) required to transport the solid material may not be required in the process and therefore will reduce process efficiency or require considerable effort to be removed before processing can begin. The previous dry feeding arrangement, the batch process feeύ method, is to load the material into a hopper, close and pressurize the hopper with gas, and then dump the material into the pressure vessel. The hopper remains filled with high pressure gas which must be vented to prepare the hopper for iαad- ing the next batch of material. Such venting and batch feeding of material is not desirable. Large valves at the inlet and outlet of the hopper are required; such valves, operating cyclically in the environ- ment of abrasive pulverized solids, have a poor effective life and reliability. Moreover, the pressurization gas contains suspended par- 1 tides of the material and cannot be vented until it is processed tα 2 remove the suspended material. 3 Other prior art centrifugal device designs have been proposed for 4 delivering dry pulverized coal to a high pressure chamber. Such prior 5 art has many serious drawbacks. First, many of these prior art cen- 6 trifugal devices (Staudinger #4,049,133, Duch #4,034,870, van cer Surgt 7 #4,120,410) reflected concern that the coal would form bridges and 8 plug the rotor channels if it was allowed to compact. Therefore, 9 there was an attempt to arrange for the material to remain in a flu- 10 idized state all the way through the rotor, as opposed to the compacted 11 plug type flow in the present invention. Fluidizεd means that the 12 material particles are separated by gas pressure forces so that there 13 is little frictional stress between solid particles. 14 unfortunately, the fluidized flow of solids cannot be stabilized when 15 pumping against a significant pressure. Furthermore, this attempt to 16 avoid compaction and plugging was misguided. As is well known in the 17 field of gravity flow of bulk (πoπ-fluidizεd) solids, stable bridges or 18 domes will not form if the dome span required is larger than a critical ^ diameter, which is dependent on the bulk material properties If the 20 channel is smaller than the critical diameter, plugging can be expect- 1 ed. A typical lg critical diameter for finely ground coal would be 22 perhaps 10-20 cm. However, the key unrecognized fact is that the cri- 23 tical diameter is inversely proportional to the body force (i.e., g- 24 force) acting on the material and consequently there is no serious 25 plugging problem in even very narrow rotor channels. This can be shewn 26 from the mechanics of dome formation and is verified by experience. 27 Thus, common experience with bin or hopper plugging problems with co- 28 hesive materials, which is obtained under 1 g gravity, is not a valid 9 guide to flow or non-flow under several thousand g's which is typical 0 of the present invention. 1 Also, none of the prior centrifugal device patents known to ap- 2 plicants have any structure which adequately stabilizes the flew of 3 solids. Nor do they attempt any separation of the control of the flow- 4 rate, or metering, from the pressure sealing function. Most used some 5 sort αf spring loaded valve or flexible structure to attempt tα control 6 the efflux of coal from the rotor (Staudinger 4,049,133; Ouch 4,034, - ■ RE- 1870; Zellerhoff 3,182,825). Also, Ouch 4,034,870 and van dεr Burgt 24,120,410 propose a cupped cymbal rotor structure where the efflux gap 3 is a continuous slit around the rim and is adjustable by moving the two 4 cups relative to one another. None of these prior structures succes- 5 sfully decouple the coal metering from the pressure sealing functions, 6 which is * of critical importance. 7 Applicants' preliminary analysis and experimental work preceding the development of the present invention is set forth in the Proceed- 9 ings of the Conference on Coal Feeder Systems, published by the Jet Propulsion Laboratory, June 21 through 23, 1977, and the Coal Feeder Oevelopment Program, Phase II Report, FE-1792-34, dated July 1977 and approved for publication October 31, 1977, Department of Energy, United States Government. Disclosure of Invention The present invention provides a method and apparatus for the continuous feeding -of pulverized or powdered solid material to a pres— surized container. This is achieved by the use of a rotor within the pressurized container through which the material is pumped into the container. The material is gas fluidized and pneumatically fed from an atmospheric feed hopper through a stationary feed pipe, then into a spin-up zone between a stationary inner hub and a rotatable driven ro- tor. Within the spin up zone the material is defluidized and compacted into a packed bed as it is centrifugally driven outward and enters ra- dial channels or sprues in the rotor. A porous compacted moving plug of material forms in the sprues and creates a seal against the high- pressure gases. The sealing action is a combined effect of both the otion of the plug and its relatively low permeability. A control noz- zle structure at the distal end of the sprues stabilizes the moving ma- terial plug and controls its outward velocity to the proper value for effective sealing. The isαbaric control nozzle structure is one of the key differ- eπces from prior art. The significant advance achieved by this struc- ture relates to the successful separation of the pressure sealing func- ion, which takes place in the sprue channel, from the flow metering function, which is mainly governed by the control nozzle outlet size. 1 The diameter of the sprue channel can then be sized to optimize the 2sprue material velocity for the pressure sealing function. This sizing 3 depends mainly on the permeability of the feedstock and the required 4mass flow rate. Typically, the sprue channel outlet diameter is much 5greater than the control nozzle outlet diameter. Ports communicating 6between the control nozzle- interior and the area surrounding the rotor 7eliminate any gas pressure difference across the nozzle. This decoup- 81es its operation from the pressure sealing function. Without a sεpar- 9ation of the sealing function from the metering function, which is ac- Ocomplished by this sprue/control nozzle combination, the machine simply 11 will not function. 12 The spin-up zone is vented to a vacuum system to allow the removal 13of excess fluidizing gas which is generated by the compaction of the 14solids and also any small amount of gas leakage back through the cαm- ISpacted moving plug in sprues from the high pressure vessel. A subatmo- 16spheric pressure is maintained in the spin-up zone in order to assure 17reliable feed from an atmospheric hopper. 18 The transition to the sprues is shaped to reduce or eliminate any 19ledges where coal could agglomerate, and channel wall angles are every- 20 here less than the critical angle of slide of the material. Sprue 21 lengths, areas, and area profiles are optimized for pumping a particu- 221ar feedstock at a particular back pressure and throughput. The sprues 23are constructed to be easily replaceable. 24 Flow sensors mounted near the rim of the rotor, separate from the 25rotor, monitor the effluxing coal streams in order to detect any plug- 26ging of the control nozzle outlets. A gas jet directed into the nozzle 27outlets is used tα restart the flow should outlet plugging occur. 28 29Brief Description of Drawings 30 Figure 1 is a partial vertical sectional view, with portions shown 31diagrammatically, of a material pressurizing system embodying this in- 32veπtion for feeding pulverized or powdered material to a pressurized 33container. 34 Figure 2 shows the sprue cross-sectional area profile used for the 35example calculations, where the cross sectional area ratio of the sp- 36rue is charted as a function of distance from the sprue outlet. 1 Figure 3 is a drawing of the sprue containing moving solids in the 2 same length scale as used in presenting the calculated results in Fig- 3 ures 4, 5 and 7, where the sprue dimension is charted as a function of 4 distance from the space outlet. 5 Figure 4 shows the calculated gas pressure distribution in the 6 sprue solids plug interstices at different solids flow velocities for 7 the example case. 8 Figure 5 shows the calculated gas pressure gradient and centrifu- 9 gal body force distributions in the sprue at different solids flow ve- lOlocities for the example case. 11 Figure 6 shows gas pressure gradient distributions in the sprue 12 for various values of the sprue solids plug permeability. 13 Figure 7 shows the calculated effect of solids flow velocity on 14gas leakage back through the sprue solids plug for the example case 15 Figure 8 shows a partial vertical view, with portions broken away, 16 of the Kinetic Extruder Rotor showing the details: of the sprue inlet 7configuration, the two sprue sections, the control nozzle structure, 8 and the nozzle pressure equilization ports. 9 Figure 9 gives a sectional view of the Kinetic Extruder Rotor of 0Figure 8 showing the sprue entrance configuration. 1 Figure 10 is an enlarged sectional view of one sprue, control nαz- 2zle, and nozzle block assembly shown in Figure 8. 3 Figure 11 is an enlarged sectional view of the control nozzle and 4nozzle block taken at right angle to the view of Figure 10. 5 Figure 12 is a schematic representation of the flowing solids in- 6side the sprue control nozzle structure.. 7 Figure 13 shows the sprue entrance region configuration for a po- 8orly flowing, material such as coal with an angle of slide of 16° 9 Figure 14 shows the sprue entrance region configuration for a more 0 free flowing material with an angle of slide of 30°. 1 Figure.15 shows one embodiment of a sprue flow detector. 2 Figure 16 shows a second embodiment of a sprue flow detector. 3 Figure 17 shows details of a gas nozzle arrangement which can be 4activated to restart the solids flow through the rotor channels in the 5event plugging occurs at one of the control nozzle outlet holes. 6 Figure 18 shows a second embodiment of a deplugger nozzle fixture. ' > •• ■ £ T Figure 19 shows a second embodiment of the optical sprue flow de- 2 tector fixture. 3 4 Best Made of Carrying Out the Invention 5 In Figure 1 there is shown, for purposes of illustration, a par- 6 tially schematic representation of a solids pressurizing system embcd- 7 ying the invention. The pressurized solids may be destined for some 8 chemical process vessel, such as a coal gasification reactor. Coal 9 gasification requires that the pressure within the reactor be maintain- 10 ed at elevated pressure, for example 30 atmospheres. Such pressures T1 have made the feeding of coal to the process difficult and expensive- 12 In the illustrated embodiment, the feeder of our invention is a 13 rotor 1 positioned within the pressurized rotor case 2. The exact con- 14 figuration of the case is a matter of choice and design so long as the 15 process gas pressure is maintained external to the rotor. 16 The material feeder of the present invention comprises a station- 17 ary feed pipe 3 for receiving material from a feed hopper 4. The feed 18 hopper is fluidized in a conventional manner by a gas injection 5 from 19 a gas supply connected to distribution plate 29 at the bottom of the 0 feed hopper 4. A normally open valve 6 may be positioned between the 1 feed hopper and the stationary feed pipe 3. The valve 6 is used only 2 during startup and shutdown αf the machine. The feed pipe 3 is equip- 3 ped wit purge taps 21 and 22 on either side of valve 6 to clear any 4 entrapped solids from the pipe before startup and after shutdown. The 5 material is fed through the feed pipe by gas fluidized solids feed, 6 which is commonly known as "dense phase pneumatic transport flow". 7 The downstream end of the feed pipe comprises a non-rotating inner 8 hub 7 and contains a right angle turn in the feed channel. Outward 9 from the inner hub structure at the outlet end is an open annular zone 0 termed the spin up zone 8. The right angle turn in the inner hub 7 1 allows the solid material tα enter the spin-up zone 8 in a radial di- 2 rectiαn. The spin-up zone and the rest of the area surrounding the in- 3 ner hub is also referred to as the "rotor eye" region. 4 The rotor 1 encloses the spin-up zone and inner hub and includes 5 a number αf radial flow channels each consisting of a sprue section 9 6 followed by a control nozzle section 10 with pressure equilization po- rts 40. The spin-up zone 8 comprises the annular space between the in- ner hub 7 and the entrance ends of the sprues. The sprue entrances are identified as 46 and the sprue outlets by 47 in Figure 1. The rotor is supported on shaft bearings 22 and thrust bearing 23 and driven by drive motor 24 via gears 25, αr any other conventional drive means. The rotating seals 26 seal the rotor shaft 27 inside and outside the rotor. The gas pressure in the spin-up zone 8 is maintain- ed at a lower gas pressure than the gas pressure in the. feed hopper by vent tube 11, which is connected tα a vacuum blower 12 or any other well-known means for maintaining low pressure through a dust filter 13. The suction typically maintains a pressure of about -2 psig tα -5 psig (-.15 to -.35 bar gage) in the spin-up zone. This assures a cαn- tinuous feed of material to the rotor from the atmospheric feed hopper. The type of material flow through the feed pipe is dense phase pneumatic transport in comparison to the more common dilute phase pneu- atic transport. For example, the material is fluidized but is main- tained at a relatively high density, approximately 20 tα 25 lbs/ft " ' (.32 to .40 gms/c ) This type αf feed allows for feeding large a- mounts of material with little transport gas and thereby minimizes the required diameter of the feed pipe. For example, in the nominal 1 Ton- Per-Hour Kinetic Extruder prototype, with a feed pipe of 3/4" diameter, feed pipe mass fluxes of (.3) to (.6) tons per hour per square centi- meter are used. Within the spin-up zone, the coal is accelerated tα the angular velocity of the rotor and compacted to a density of 40-50 lbs/ft (.64 to .80 gm/cm ) before entering the sprues 9.- The coal is non- fluidized in the sprues and flows therein as a compacted porous plug of granular solid material. The dot shaded areas indicate the portions of the machine which run filled with coal during feeding — light dot sha- ding for lower density fluidized coal, (.32 tα .40 gm/cm ), heavy dot shading for compacted coal( .64 to .80 gm/cm ). The compaction process in the spin up zone produces gases which must be drawn out through vent 11 by the vacuum system in order to ma- iπtain the low pressure in the eye of the rotor. The quantity of gases produced amounts to approximately 1 standard cubic foot per minute (SC- FM) f or a one ton per hour feed. Vent 11 also removes any gases leak- 1 ing through the sprue plug from the high pressure region. 2 Additional secondary channels communicating with the rotor eye re- 3 gioπ via the inner hub are a pressure tap 14 and a flushing gas line 4 15. The pressure tap 14 is used to monitor the rotor eye pressure in 5 order tα warn of abnormal conditions and can be used to detect the lass 6 of a solid plug in one of the sprues. 7 The flushing gas is a small gas flow into the rotor eye which as- 8 sures the suction vent tube always has a minimum gas flow through it. 9 without this flow a relatively dense stream of solids can be drawn into. 0 the suction line under certain conditions, leading to a chance of plug- 1 ging the vent tube. The flushing gas flow rate can either be a fixed 2 quantity or it can be regulated according tα the rotor eye pressure. 3 The flusing gas supply system (not shown) can be αf any conventional 4 type. 5 The flushing gas line 15, vent tube 11, and the pressure tap 14 6 all communicate with the rotor eye region at points close to the rota- 7 tiαnal axis in the narrow gap (e.g., 3mm) formed between the rotor and 8 the non-rotating inner hub structure 7. Centrifugal action in this re- 9 giαn limits solids entry into the vent tube 11. 20 The inner hub configuration allows for coal entry in the radial 2.1 direction. This allows the solids feed into the rotor to be self regu- 22 lating. The feed pipe is sized so that at the pressure drop maintained 23 by the vacuum system the maximum rotor throughput can be comfortably 24 supplied. The flow of material into the rotor is then controlled by 25 the choking αf the feed pipe outlet by the complete filling of the spin 26 up zone (8) up to the feed pipe outlet radial position (16) . Faster or 27 slower withdrawal of material through the sprues results automatically 28 in greater or lesser feed αf material into the rotor. 29 Coal exits the rotor through a plurality of control nozzle outlet 30 holes 17 into the pressurized rotor case 2. Surrounding the rotor dur- 31 ing operation is a dilute suspension of solids. A vortex is set up in 32 the case by the spinning rotor and during feeding the solids raoidly 33 drift radially outward and down through the slotted baffle 18, into an 34 accumulator section 19 making up the lower portion of the case. The 35 baffle 18 is designed to isolate the vortex set up by the rotor from 36 the accumulator section. In the accumulator section 19 the solids are 1 settled and transferred by a conventional pneumatic pick-up system, or 2other means, to a reactor or another high pressure hopper. Since es- 3sεntially only coal enters the case through the rotor, while a mixture ' 4of both coal and gas leaves the accumulator section, pressurizing gas 5must be continuously supplied to the case via port 20. 6 In Figure 1 the general layout of the machine is a vertical, can- 7tilever shaft rotor with both the material being fed and the power be- 8ing applied from the top of the pressure case. However, a hori- 9zontal shaft rotor with the material being fed from one side and the 10power being applied by a drive shaft entry from the opposite side of lithe case has also been successfully operated. This horizontal shaft 12type αf machine has certain mechanical advantages. From the standpoint 13of the invention, including the coal flow inside the rotor, there is 14essentially no difference between the two arrangements. In order tα 15enhance the understanding of the invention, the physics of the fσrma- 16tion of the moving porous plug in the sprues will be explained. 17- * It must be stressed that the Kinetic "Extruder is for a dry, pαw- Iδdered or granular material feedstock. The flow physics for a powdered 19or granular material are different from the flow physics of a liquid 20material. Fundamentally, a liquid cannot support a shear stress with- 21 out flow, while a granular material can. For example, a column of gra- 22nular material, such as in a grain silo, does not exhibit a continuous- 23ly increasing bulk solids stress or pseudo-pressure with depth as would 24a similarly sized column of liquid. A hydrostatic like stress distri- 25 ution exists only a very few diameters below the bed surface in a gra- 26nular material and thereafter the stress in the column remains constant 7regardless of depth, the column weight load being taken up by shear 8stresses on the containing walls. Furthermore, the stress distribution 9is little affected by whether or not the column is in motion or sta- 0tic. The stress in a granular material column may be computed from the 1well known Janssen's equation which expresses the asymptotic leveling 2of stress with depth. Similar column stress effects occur in the dis- 3closed Kinetic Extruder sprues. 4 A distinction should be made between the bulk solids stess and the 5gas pressure in the interstitial pores between the grains of material. 6The gradient in gas pressure (i.e., the pressure change per unit length - 10 - 1 of sprue) represents the main force which must be overcome by centrifu- 2 gal force to feed the material through the Kinetic Extruder sprues. 3 The main sprue channel design criteria for the present invention 4 is a proper matching between the body force distribution and the gas 5 pressure gradient distribution in the channel. As long as the body 6 force exceeds the pressure gradient, keeping the bed stressed tα seme 7 degree so the sprue plug maintains its integrity, the movement of the 8 material will be stable. This requirement is virtually local in char- 9 acter because αf the short effective distances over which solids bed 10 stresses can build up. That is, due to the Janπsεπ effect the bed str- 11 esses cannot build up and push the sprue material through even a short 12 local region where the gas pressure gradient exceeds the cεntrifugal 13 body forcε. 14 A mathematical method for salving far the gas pressure distribu- 15 tions in the sprue channel has beεn dεvεlopεd. The basic governing e- 16 quatiαπs describing the percolation of gases through the porous, mov- 17 ing, sprue material medium are Darcy's law, exprεssiαns αf.mass cαnser- 18 vation for the flowing solid and the gas, and an equation αf state for 19 the gas. Figures 2 to 7 illustrate calculatεd rεsults which highlight 20 the important considerations for sprue channel design. 21 Figure 2 shows the sprue cross-sectional area profile assumed for 22 the example calculation. Therε is plαttεd the ratio of the local sprue 23 area to the sprue outlet area, A/A. 7 against the distance from the 24 sprue outlet, Z. Other important variables are the sprue length, the 25 pressure differεnce across the sprue, the solid material bed properties 26 (bulk density, porosity, and permεability), thε viscosity αf thε gas, 27 and thε vεlocity of thε solids bεd within thε spruε. Rεsults shown in 28 Figures 3-7 correspond to the following values of thesε kεy paramεtεrs: 29 30 Sprue Lεngth 25 cm 31 Sprue Inlεt Gas Pressure 1 atm 32 Sprue Outlet Gas Pressure 30 atm 33 Sprue Outlεt Solids Vεlocity 0 to 1.3 m/sεc 34 Solids Bed Bulk Density 0.67 gm/cm 3 35 Solids Bed Porosity 0.50 36 Solids 8ed Permeability, K 3.7 x lθ "13 m 2 (0.38 Darcys) 1 -5 2 Gas Viscosity 1.8x10 nt-sec/m 2 3 The solids bed prαpertiεs arε characteristic αf a 70%-200 mesh coal 4 grind at the state of compaction typically occurring in the Kinetic 5 Extruder sprues. 6 Figure 3 shows a drawing of thε spruε containing moving solids in 7 the same length scale and orientation as used in plotting the calcula- 8 tsd results in Figure 4, 5, and 7 In Figure 3, the positive direction 9 αf solids motion is denoted by the arrow S and the positive direction i> Z O of gas leakage motion is denoted by the arrow G. Figure 4 shows the 1 gas pressurε ,P, distribution in the sprue solids plug intersticies as 2 a function of Z for several values of solids velocity through the sp- 3 rue. The three curves shown correspond to sprue outlet solids veloci- 4 ties ,V, αf 0, 0.7 m/sec, and 1.3 m/sec. The sprue outlet solids velo- 5 city V is usεd hεrε as the reference variable for the rate of solids 6 flow through the sprue. It may be noted that because the sprue cross- 7 sectional area decreases considerably from the inlet to the . outlet end 8 of the sprue, aπca the bed density is constant throughout, the local vε- 9 locity of the solids is correspondingly lower toward the inlet (Z = 25) 0 end of the sprue. Figure 4 shows clearly that the pressurε distribu- 1 tion is sensitive to the flow velocity of the solids at the outlet. Fi- 2 gure 5 gives the same results in ^ terms of gas pressure gradient^ dz J distributions (i.e., pressure 5 change per unit length of sprue). The solid lines in Figure 5 represent 6 the pressure gradient as a function αf distance Z along the sprue. As 7 discussed, the gradient in pressure comσrisεs the opposing force which 8 the centrifugal force must overcome. The formula showing that the cen- 9 trifugal force must exceed the pressure gradient is expressed as gal body force j s bed density r s distance from rotational axis = rotational speed. - 12 - 1 Centrifugal force distributions in the sprue are shown as the dashed 2 lines in Figure 5 for rotor speeds of 3000 rpm and 3500 rpm. In these 3 examples the rotational axis is assumed tα be 13 cm from the sprue in- 4 let. As shown in Figure 5, higher solids velocity leads to higher pre- 5 ssure gradients at the outlet (Z = 0) end αf the sprue and accordingly 6 higher rotational speeds would be required unless the optimum solids 7 velocity is used. For example, an outlet solids velocity of 1.3 m/sec 8 and a rotor speed of 3000 rpm would not be compatible since the pres- 9 sure gradient near the sprue outlet excεεds the centrifugal force in 0 the material at that point. In consequence, the sprue plug is unable to 11 flow at this velocity. Attempts tα operate under such conditions have 2 been found to yield flow stoppages and blowbacks of high pressurε gases 13 into thε rotor eye owing to the complete loss of the integrity of the 1 sprue plug. On the other hand, as shown in Figure 4, operating at an 15 outlet velocity of 0.7 m/sec and 3000 rpm gives a stable situation. In 16 design for a particular mass flow rεquirεmeπt, for example 1 ton/hr, 17 the optimum sprue flow velocity can be accommodated by sεlεctiαπ αf 18 the sprue outlet size (cross-sectional area) which yields this velocity. 1 Figure 6 illustrates the effect of changes in the sprue solids 20 plug permeability on the sprue pressure gradient.distributions. For 21 the calculations the solids throughout was fixed (outlet velocity , V = —132 220.7 m/sec) and the per εability ,K, was varied from 1.9 x 10 " m -132 23 to 5.6x10 m . As shown in Figure 6, decrεasing pεrmeability has 24 a similar effect as increasing solids velocity. The key factor is the 25 ratio of solids velocity to permεability. A low permεability feedstock 26 requires a low solids velocity in the sprue. Conversely if the mater- 27 ial is more permeable, higher velocities may be used while still ain- 8 taining favorable pressurε gradiεnt distributions and lεakagε charac- 29 teristics. It is also found that the lεngth of the sealing sprue plug 30 plays a similar role, shorter plugs requiring higher solids velocities 31 to produce zero lεakagε. Shorter spruεs also mεaπ higher avεragε pres- 32 sure gradients and therefore necessitate higher rotational speeds. 33 Finally, the sprue area ratio (inlat arεa/outlet area) and area 34 profile may be varied. Sincε thε gasεs εxpand in pεrmεating through 35 thε sprue plug, compensating area changes are rεquifad. Thε Figure 2 36 profile is a good choice far the examplε with a prεssurε ratio of 30. ■ - ■ 2- 1 Higher pressure ratios would typically require higher area ratios. 2 Figure 7 illustrates the gas flow velocity V through the porous 3 bed in the sprue at the inlet end (i.e., into the spin-up region) as a 4 function of the outflow velocity αf the solids, V. It may be noted 5 that therε is a critical solids velocity (0.75m/sec in this example) 6 which yields no gas flow- hrough thε sprue in either direction. For a 7 solids outlet velocity less than the critical value, indicated by arrow 8 200, some high pressure gases permeating through the sprue plug are 9 able tα reach the rotαr eye. Above the critical solids velocity, (as 0 denoted by arrow 202) no leakage occurs and some of the gas originally 1 trappεd in thε bεd pores passes through the sprue with the solids. If 2 the feedstock properties, the key one being permeability, were known to 3 havε little or no variability, the critical solids velocity would be the optimum operating point. However, due tα variable feedstock pro- perties it is best tα design for operation with some minor net leakage into the rotor eyε. This makεs thε machinε less sensitive tα feεdstαck properties fluctuations. Figures 8, 9,10 and 11 show additional details of the rotor con- structiαn. As shown, the sprues and the control nozzles are made as replaceable parts, with the sprues, in two sections. This allows these parts, which are exposed to abrasive type wear, to be conveniεntly made from hard wear resistant materials. It also allows the rotαr to be more easily reconfigured to accommodate changes in requirements — i.e., changes in requirεd throughput, delivery pressure, or feεdstock permeability. As shown in Figures 3 and 9 and in the sprue/control nozzle assembly detail drawings represented by Figures 10 and 11, the sprues 9 consist of a funnel section 30 in conjunction with sprue body sections 32. The control nozzles 10 are held against the distal end of the sprue body section by the nozzle retaining blocks 36 which are at- tached to the rotor 1 by screws 38. Pressurε equalization ports 40 co- mmunicate between the control nozzle interior and the rotor extεriαr. 0-riπgs seals 44 seal between the sprue sections and between the sprues and the rotor. In Figure 9, it can be seen that the sprue inlets 42 have a rectangular shape so that they nestle together in such a way as to present maximum open area to the radial movement of the flowing coal. Figure 12 illustrates the functioning of the control nozzle. This T shows a portion of the sprue channel 51, including its distal end 53 in 2 conjunction with the control nozzle 55. The moving compacted solids 57 3 within the sprue channel and control nozzle are denoted by the shaded 4 area. Thε control nozzle outlet 50 in the rotαr rim 58 is the narrow- 5 est point in the flow channel and acts as the choke point for the ov- 6 ing plug of solids. The coal egressing from the sprue forms a cone 7 shapεd frεε surface 52 according to the material angle of repose, leav- 8 ing a coal free, gas filled, space 54 above the solids. This space is 9 connected to the rotor surroundings via a port or channel 40 so the gas 10 pressure (P ? ) within the control nozzle is substantially the same as IT the delivεry pressure (P,) due to gas inflow denotεd by arrows 56. 12 Under this condition (i.ε., -? 2 - P,) it is found that thε mass flow 13 rate through the nozzle is only depεndεnt on thε nozzlε outlet diamet- 14 εr, d, and the rotational speed or g-fαrce, according to thε εquation: .- m r .5/2 r l/2 15 m 3 Cd G 16 17 whεre 18 19 m nozzle mass flow rate (Kg/sec) 20 d = αutlεt dia εtεr (cm) 2 21 G = Centrifugal acceleration (g's) = rw /g 22 r = rotor radius, w 3 rotαr angular speed 5/2 23 C = empirical constant = 0.044 Kg/sec/cm from tests with coal. 24 The function αf the control nozzle is thus to metεr thε material 25 flow and also tα stabilize the flowing material plug in the sprue. Up 26 to a certain limiting pressure, the control nozzle runs filled to the 27 extent shown in Figure 12 and the throughput is independent of delivery 28 pressure, being only a function of rotor speεd as given above. Under 29 conditions wherε thε cεntrifugal fαrcε is insufficiεnt in comparison to 30 the sprue pressure gradient, and the maximum mass flow which can be de- 31 liverεd by the sprue is lεss than m, thε control nozzlε "starvεs". 32 That is, atεrial is not suDplied to the nozzle fast enough tα maintain 33 a back-up of material within the nozzle which extends to the distal end 34 of the sprue. This lack of back-up of material removes the distal sup- 35 port to the material plug in the sorue. If this occurs, it has bεεn 36 found experimεntally that the material plug in the sprue is unstable, and "blowbacks" of high pressure gases into the rotor due to a complete loss of the integrity of the sprue plug can be the result. The sprue instability situation is somewhat similar to a filled, inverted bottle, with the opening just benεath the surface of a pool of liquid. So long as thε bottle opening is evεn slightly submεrgεd, atmosphεric prεssurε keeps the bo tle.filled. However, when the bottle is lifted out of the pool, the free liquid surface at the σpεning is unstable and the bottle empties in the familiar unsteady bubbling manner. After exiting the nozzle outlet hole in the rotor rim, the solid material forms a plume 60 which is blown taπgεntially back along the rotor periphery due to the motion of the rotor 61 with respect to its gaseous environment. The radial velocity of the coal passing through the nozzle outlet is quite low in comparison tα its tangential velocity which is the rim speed αf the rotor (e.g., 40 ft/sec vs. 500 ft/sec). Figures 13 and 14 show sections of the sprue entrance configura- tiαns for two example designs. They illustratε two particular require- ments which must be met by the inlet region design. First, the wall surfaces along which the solid materials slides must be steep enough so that sliding does indeed take place. Figure 13 shows sprue walls with constant angles of 16° with respect to the cεntrifugal body force ve- ctor. In thε rotational field such constant angle walls are curved su- rfaces, as shown. The Figure 13 example is suitable for a fairly poor flowing material such as coal. The use αf straight sprue walls with a 16 slide angle at the inboard end would, αf course, also assure at- erial flow. However, it would then require a longer sprue channel tα obtain the same area contraction and therefore this would be a less ef- ficient design. Figure 14 shows a similar design far material which is more free flowing and has a less steep anglε of slidε (30° wall angle). For such a material, a smaller number of larger cross-section sprues could be used. Another consideration is that the sprue inlets must be arranged to present a maximum percentage of open area to the flowing coal. In one enbodiment of the invention the inlets are rectangular. If the inlets were round, for example, there would be considerable space between the flow channels where the coal could build up and extend into the spin up 1 zone. 2 Such build ups arε undεsirεablε sines thεy reduce the effective 3 size αf the spin up zone. Moreover, hardened lumps of coal may form, 4 over time, which, should they become dislodged and εnter the sprues, 5 could plug the control nozzle outlets. Such lumps tend to often become 6 dislodged during shut down of the machine when the coal feed is cut off 7 and the rotor drains out of coal. By εliminating any placεs where coal 8 may hang up, this problem is avoided. 9 Figures 15 and 16 show two types of sensor devicεs far monitoring TO thε individual coal streams issuing from the rotor rim. One type de- TT tects the impact of the coal streams by means of a piezoelectric trans- T ducer mounted near thε rotαr rim. The other uses a light source and 13 photodetector with the coal streams interrupting the light beam. The 14 signals from eithεr detectors may be displayed on an oscilloscope with 15 the swεep exactly synchronized with the rotor revolutions by means of a 16 conventional magnetic pickup and marker on the shaft αr rotor (not sho- 17 n). Individual sprue flows are readily idεntifiablε on thε display. 18 It is found that at high rotor case prεssure the individual coal stre- 19 ams only maintain their individuality out to a fεw millimεtεrs from the 20 rotor rim. The sensors must be placed at such distances in order to 21 obtain good signals. 22 The sensor devicε shown in Fig 15 consists of a sεnsor assembly 70 23inserted through the rotor case 2 and juxtaposed to the rim of the ro- 24tor 1. A laser or other collimated light source (not shown) is attach- 25ed. to the bracket 72 so that the light beam passes into the inlet tube 2674 and through the sealed glass window 76 into the pressurized envirαn- 27 ent of the rotor case. The light beam thεn passεs through the small 28tubes 78 which are separated by the short gap 80. The gap 80 is imme- 29 iately adjacent to the control nozzle effux holes in the rotor rim so 30that the effuxing coal streams interrupt the light bεam as each hole 31passes. The light tubes 78 are purged continuously with clear gas wh- 32ich is introduced at port 82 and distributed to the light tubes via 33passage 84. Purging is utilized and the gap 80 is kept as short as 34practical, becausε thε dεπsity of the suspension of coal surrounding 35the rotor severεly attenuates the light. 36 After traversing gap 80, the beam passes through a fiber optics light guide 86. The beam is then conveyed via the fiber optic cable to any conventional means for converting the light to an electronic sig- nal, such as a photodiode devicε (not shown). Figure 16 shows another embodiment of a sensor. This sensor is built around a conventional piezoelectric pressurε or impact transducer loo. The transducer is protected from the high pressure suspension by the pressure housing 102 and seal 103. Coal emitted from the control nozzle outlet holes strikes the end αf hardened rod 104. The impact point 105 is alignεd with the nozzle outlet holes and positioned close tα the rim of the rotor 1. The rod 104 is held in contact with the ac- tive face of the transducer 106 so the impact αf the coal is detected. The sensor is mounted on hollow support bar 110 with the elεctrical si- gnal cable 108 passing through the support bar. The sensor position is adjusted by means of rotation and translation of support bar 110. Once adjusted, the support is locked by means αf clamp 112. The device is mounted on flange 114 which is attached to the pressure case 2 enclos- ing the rotor. The monitoring equipment is used to detect any flow stoppages or partial flow stoppages of the coal streams. It has been found that the device shown in Figure 17 can be used to restart the flow should a ro- tor outlet hole becomε pluggεd. This dεpluggεr device consists αf a small stationary gas nozzle which is directed toward the rim of the rotor. This is mounted close to the rotor rim so that the gas jet bri- efly strikes all of the control nozzle outlets in turn as each passes. Should an outlet hole become plugged, the gas jet is turned on and in- variably restarts thε flow almost instantaneously. The jet has no sig- nificant effεct on thε opεrating spruεs, and no interruption of pumping is required. in the embodiment αf this flow restarting devicε shown in Figurε 17, the deplugger gas nozzle 130 is attached to gas conduit pipe 132 with the nozzlε 130 outlet aligned with the control nozzle coal outlet holes in the rim of rotor 1. The gas is introduced at fitting 134 from a high pressure gas supply (not shown) ; the gas flow may be turned on and off by a solinoid valve or other conventional means. The deplugger device is mounted on flange 136 attached to the rotor case 2. A con- ventional flex joint 138 with pivot center 140, for example, the flex T joint shown in U. S. Patεnt Numbεrs 3,360,895 and 3,390,898, allows thε 2 depluggεr nozzle tα be swung to position 141 out of the path of thε co- 3 al streams when not in use. This reduces abrasive wear an the nozzle. 4 Flex joint movement is induced by pneumatic actuator 142 and linkage 5 144, or any other standard type of linear actuator. 6 Figure 18 shows another embodiment of the flow restarting devicε. 7 In this embodiment, a pair of gas nozzles 160 are used from which gas jets co-impinge on thε coal efflux hales in thε rim of thε rotor 1. Thε 9 fixturε 161 contains thε nozzlεs 160. The fixture . 161 is slotted sα that coal issuing from the rotor passes through the slot 162 instead αf T impinging directly on the fixture. This avoids erosivε wεar on thε fixture. The devicε is mounted on a standard flange 159 attached to the pressurε case. Gas is fed into the devicε at fitting 164 from a high pressure supply (not shown) as in the prεvious embodiment. The gas is conveyed to the nozzles 160 via channels 166. Figure 19 shows a second embodiment of the light beam coal flow monitoring device. In this device, light is introduced at one of the. optical fiber cable connectors 178 from a standard type light source (not shown). The light passes down optical fiber cable 180, across gap 182, and thεnce into optical fiber cable 181. The light is modulated by the coal streams issuing from the rotor 1, as in the prεvious em- bodiment shown in Figure 15. The modulatεd bεam is conveyed through opposing optical cable 181 and connector 179 to a conventional means for converting the light to an electronic signal as in the σrevious embodiment. Annular channels 184 surround the ends αf the optical fi- ber cables which defiπε thε gap 182. A purgε gas flow through these channels keeps window ends αf the optical fibers clean. The purge gas is introduced via fitting 186 from any conventional type gas supply (not shown). The sensor fixturε 188 is mounted on a standard flange 19 Q to the pressure case 2. The fixture 190 is juxtaposed to the coal nozzlε outlet holεs in the rotor rim, as in thε previously discussed εmbodi επt. Illustratively, a pulverized material feeding apparatus embodying this invention and having the following characteristics was operated: Feedstock: Coal ground to 70% passing 200 mesh Throughput: 1,000 Kg/H Delivεry Prεssurε: 28 atm Rotor Dia εter: 71 cm Number of Sprues: 12 Sprue Length: 22 cm Sprue Outlet Diameter: 0.72 cm Control Nozzle Length: 3.8 cm Control Nozzle Outlet Diameter 0.21 cm Rotor Speed: 3,600 rpm Maximum Channel Wall Slide Angle: 16° Suction Gas Flow: 3.5 SCFM Other modifications and advantageous applications αf this inven- tion will be apparent to those having ordinary skill in the art. There- fore, it is intended that the matter contained in the foregoing descri- ption and the accompanying drawings is illustrative and not limitative, the scope of the invention being defined by the appεπdεd claims. ι u Λ .

Claims: CLAIMS 2 3 1. Apparatus for fεediπg a pulvεrizεd atεrial from a supply so- 4 urce to a container against a pressure diffεrεntial, said apparatus in- 5 eluding a stationary feed pipe, said stationary fεεd pipε having an iπ- 6 put end and an output end,, said feεd pipε adapted to feed pulverized 7 material from the Input end to the output end, said output end includ- 8 ing at least one radially extending opening and defining an innεr hub; 9 a rαtαr, said rotor includεs a plurality of radial spruεs, εach spruε TO including a proximal end and a distal end defining a passage for pas- 11 sage αf said pulverizεd material, said rotor rotatably mounted coπcεn- T2 trically with raspεct to said innεr hub αf said stationary fεεd pipε T3 and said rotor located so that the proximal ends of the sprues are jux- 14 tapαsed to said inner hub, the space between proximal ends of the spru- 15 es and said inner hub forming a spin up zone wherε said pulvεrized ma- 16 tεrial emitting from said output end of said stationary feed pipe is 17 accelerated before entering into said sprues of said rotating rotαr sa- 18 id rotor further adapted tα maintain a compacted moving plug of said 19 material in said sprues therεby forming a sεai against the pressurε in 20 said cαntainεr, said sεals' εffectivεnεss being partly depεndεnt on thε 21 throughflαw vεlocity of said compacted moving plug in said sprues, and 22 wherein the means for control of said throughflαw velocity is indepen- 23 dent of the pressure levεl in said containεr. 24 2. The apparatus for fεeding a pulverized material as defined in 25claim 1, wherein each sprue including a first and second section, said 26 first and second section defining a passage having rectangular cross 27 section shape at the proximal end of said first section to thereby sub- 28stantially eliminatε ledges on the proximal end of said rotor. 29 3. The apparatus for feeding a pulverized material, as definεd in 30claim 2, whεrein said first section of said plurality of sprues definεs 31 a passage having a relatively large cross sectional area reduction in 32the radial direction, and wherε said passagε has a cross sectional area 33having a transition from a rectangular to a circular cross sectional 34shape. 35 4. The apparatus for feeding a pulverizεd matεrial as dεfinεd in 36claim 1, including venting means to remove excess gas from the hub re- 1 gion. 2 5. The apparatus for feeding a pulverizεd material as defined in 3 claim 4, wherεin said venting means is adapted to maintain a pressure 4 difference between said feed pipe and said spin up zone. 5 6. The apparatus for feeding a pulverized material as definεd in 6 claim 5, further defined- as including means for spinning said rotor rs- 7 lative to said feed pipe and said inner hub. 8 7. The apparatus for feeding a pulverized material as defined in 9 claim 1, further definεd as including means for spinning said rotor re- 10 lative to said feed pipe. IT 8. The apparatus for feeding a pulverized material as defined in 12 claim 1, including a fixed geometry isobaric-control nozzle structure 13 at the distal end of each of said sprues, said nozzle structure de- 14 signed to maintain a stable plug of the pulverizεd matεrial in said 15 sprues and to control the flow of said material indepεndεnt of the gas 16 pressure in the said container immediately external to said rotor, and 17 said nozzle structure includes at least one port permitting gas pres- 8 sure tα equalize between the pulverized material within said nozle str- 9 ucture and said containεr. 0 9. Thε apparatus for feeding a pulverized material as defined in 1 claim 1, wherein said stationary feed pipe is further definεd as inclu- 2 ding a secondary channel, venting means, said venting means connected 3 to said secondary channel for removing gas from the spin up region. 4 IQ. The apparatus for feeding a pulverizεd material as defined in 5 claim 9, wherεin said venting means is adapted to maintain the pressure 6 at said spin up zone at a lower pressurε than the pressurε at said sup- 7 ply sourcε. 8 11. The apparatus for feeding a pulverizεd material as dεfined in 9 claim 9, wherεin said secondary channel communicates with said spin-up 0 zone by way of a narrow gap disposed between the end of said inner hub 1 and said rotαr. 2 12. The apparatus for feeding a pulverizεd material as defiπεd in 3 claim 9, wherein said stationary feed pipe is further defined as in- 4 eluding a third channel for injecting gas into said spin-up region. - * -- 13. Apparatus for feeding a pulverizεd matεrial from a supply 6 sαurcs to a containεr against a prassurε diffεrential, said apparatus 1 including a stationary feεd pipε adaptεd to fεed pulverizεd matεrial 2 from thε input εnd to thε output end, said output end including at le- 3 ast onε radially εxtending opening and defining an innεr hub; a rotor, 4 said rotor includεs a plurality of radial spruεs, each sprue including 5 a proximal end and a distal end defining a passage for passage αf said 6 pulverizεd material, εach spruε furthεr defined as including a first 7 and second section, said first and second section defining a passagε 8 having rectangular cross sεction shape at the proximal end of said fi- 9 rst section to therεby substantially eliminate ledges on the proximal TO end of said rotor, said first section defines a passage having a cur- TT vature defining a constant angle bεtweeπ the radial accεlεration vεctαr T2 and thε wall αf said passagε. said first sεctiαn defines a passage hav- 13 ing a curvature defining a constant angle between the radial accεiεra- T4 tion vεctor and the wall αf said passage. T5 14. The apparatus far feeding a pulverizεd material as defiπεd in 16 claim 13, wherein said second sεctiαn of said plurality of spruεs de- 17 fines a passage having a relativεly -small' cross sectional area rεduc- T8 tion in the radial dirεction. T9 15. Thε apparatus for feeding a pulverizεd matεrial as dεfinεd in 20 claim 14, including an isobaric control nozzle at the radial end of ea- 21 ch of said spruεs. 22 16. Apparatus for fεεding a pulvεrizεd material from supply sou- 23 rcε to a housing maintainεd at εlεvatεd prεssure, said apparatus inclu- 24 ding a rotor, disposed in said housing and operably cαnnεctεd to the 25 feεd mεans for rscεiviπg the pulverized material and discharging it 26 within the housing, said rotαr including a first mεans to form a plug 27 of thε material, a second pressurε balancεd mεans sizsd to control the 28 flow αf said matεrial through said rotor and through said apparatus, 29 spacsd from thε outlεt αf the first means and substantially in aligπ- 30 ment thεrewith and said apparatus also including means for feeding pul- 31 verizεd material to the proximal end of said rotor. 32 17, The apparatus for feeding a pulverizεd matεrial as dεscribed 33 in Claim 16, wherεin said, second means is further describεd as includ- 34 ing an isobaric control nozzle having a fixed gεomεtry. 35 is. The apparatus for fεεdiπg a pulverized material as described 36 in Claim 17, wherεin said control nozzle includes at lεast one fixed port communicating with the interior αf said housing, for maintaining the junction betwεen said first and second me bεr at the same prεssurε as thε prεssurε in said housing. 19. Thε apparatus for fεεding a pulvεrizεd matεrial as dεscribεd in Claim 18, whεrεin the output of said control nozzle is substantially smaller than the output of said plug forming means. 20. Thε apparatus for feeding a pulverized material as dεscribεd in Claim 19, wherein the cross-sectional area- of the output αf said plug-forming means is substantially three times the cross-sectional area αf the output of said control nozzle. 21. The apparatus for feeding pulverizεd material as defined in Claim 16, wherεin said first mεans dεfines a passagε for the pulverizεd matεrial having a curvature defining a constant angle between the ra- dial acceleration vector and the wall of said passage. 22 The apparatus for feeding a pulverizεd matεrial as dεfinεd in Claim 21, whεrεin said first means has a rectangular cross-sectional area at the proximal end. 23. Apparatus for feeding a pulverizεd material from supply sou- rce tα a housing as defined in Claim 22, including a spin-up zone where said pulverized material is accelerated prior to entering said first means, the proximal end of said first means intermediate and juxtapα- sitionεd with said spin-up zoπε. 24. Thε apparatus as defined in Claim 23, including•means for maintaining said spin-up zone at a lower pressure than the pressurε in thε input dεvice to said pulverizεd matεrial feeding apparatus. 25. Apparatus for feeding a pulverized material from a supply source to a container against a pressure differential, said apparatus including a stationary feed pipe, said stationary feed pipe having an input end and an output end, said feεd pipε adapted tα feed pulverizεd aterial from the input end to the output end, said output end includ- ing at least one opεning, a rotor substantially in alignmεnt with said feed pipe for receiving the material discharged from said stationary feed pipe, said rotor includes a plurality of radial sprues, each sprue including a proximal end and a distal end defining a passage for pas- sagε of said pulvεrizεd matεrial, said rotor further including a fixed geomεtry control nozzlε at thε distal end of each of said sprues, said 1 control nozzle comprising a structure designεd to maintain a stabls 2 plug αf thε pulverized material in said sprues and to control the flow 3 αf said material iπdependεnt αf the gas prεssurε in thε said cαntainεr 4 immediately external to said rotor. 5 26. Thε apparatus for fεeding pulverized material as definεd in 6 claim 25, wherein said nozzle includes means permitting gas pressurε to 7 equalize between the pulverized matεrial within said nozzle and said 8 container. 9 27. The apparatus for feeding a pulverized material as defined in 10 Claim 25 including sensing means for sensing the flow of material thrα- TT ugh the said control nozzle. T2 28. The apparatus for feeding pulverized material as dεfinεd in 13 claim 27, wherein said sensing means is further defined as a detεctor 14 where said light beam is disposed to be interruptεd by pulverized ma- 15 terial effluxing from said control nozzles thereby modulating the sig- 16 nal produced by said photodetεctor. 17 29. Thε apparatus for feeding a pulverized material as defined in 18 Claim 25 including means for clearing the sprue and control nozzle said 19 clearing means disposed adjacent and spaced from the control nozzle 20 outlets and substantially in alignment therewith for clεaring any plug- 21 gεd sprues. 22 30. The apparatus for feεding a pulvεrized material as definεd in 23 claim 29 including sensing mεans for sεnsing thε flow of material thro- 24 ugh the said control nozzle said sensing means disposed adjacent and 25 spaced from the control nozzle outlet. 26 31. The apparatus for feeding pulverizεd matεrial as dεfinεd in 27 claim 27, whεrein said sensing means is further defined as a piezoelec- 28 trie device disposεd so that said pulvεrized material issuing from said 29 control nozzles strikes said piezoelectric device producing a modulated 30 electronic signal. 31 32. The apparatus for feεding a pulvεrizsd material as definεd in 32 claim 29,. wherein said clearing means is further definεd as a gas noz- 33 zle, said gas nozzle disposed to produce a gas jet impinging on said 34 control nozzlε outlets. 35 33. A method αf feεding pulvεrizεd material from a supply source 36 to a high pressure housing comprising the steps αf: OMPI 1 fluidizing the pulverized material in a stream of gas at a pres- 2 sure P. , 3 transporting the pulverized material tα a spin-up zone, said spin- 4 up zone being at a pressurε P„ cεntrifugally saparating the pulvεr- 5 ized material from the transport gas, 6 removing said transport gas at the cεntroid of thε spin-up zone, centrifugally driving the pulverized material into a plurality of 7 rotating sprues, 8 forming a compacted plug of the pulverized material in the sprues, 9 and controlling the flow of pulverizεd material into the high pressure 10 housing having a pressure P, by a control nozzle cooperating with 11 each sprue. 1 34. The method of Claim 33, wherεiπ the transporting stεp com- 13 prises feeding the pulverized material through a stationary feed pipe 14 and axially into the spin-up zone. 15 35. The method of Claim 33, wherein the pressurε P, is sub- 16 stantially higher than the pressure P, and wherein the prεssure P 2 17 is slightly less than the pressurε P, . 18 19 20 21 • 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Inventors: BONIN J, DANIEL A, MEYER J
Applicants: LOCKHEED MISSILES SPACE, LOCKHEED MISSILES SPACE CO INC
Application year: 1981
Main classification: B65G65
IPC codes: B01J3, B65G53, B65G65, C10J3