US2059435A - Feeding device and a process of using the same - Google Patents

Description

NOV. 3, 1936. H, J BRQWNLEHE 2,059,435

FEEDING DEVICE AND A PROCESS OF USING THE SAME Nov. 3, 1936.

H. J. BROWN LEE 2,059,435 FEEDING DEVICE AND A PROCESS OF USING THE SAME Filed June l6. 1950 3 Sheets-Sheet 2 k Q i g: 1 m i gm E3 fi Q? Er i N 1 &

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FEEDING DEVICE AND A PROCESS OF USING THE SAME Filed June 16. 1930 3 Sheets-Sheet 3 Patented Nov. 3, 1936 FEEDING DEVICE AND A PROCESS or USING THE SAME Harold J. Brownlee, Cedar Rapids, Iowa,

Company, Chicago, 111., a corto Quaker Oats poration of New Jersey Application June 16, 1930, Serial No. 461,293 20 Claims. 01. 260-44) My invention relates to improvements in feeding devices, with special reference to devices for continuously feeding various materials, such as oat hulls, rice hulls, cotton seed hulls or other pulverulent compressible material of a similar nature, into and out of a chamber in which a comparatively high pressure is continuously maintained.

More particularly my present invention pertains to a device for continuously feeding pentosen-bearing material, such as oat hulls, into an autoclave or digesting chamber wherein furfural is manufactured under suitable conditions of steam pressure and temperature, and for removing the residue therefrom after the digesting process has been completed.

While my invention may be used for feeding material continuously into and out of any suitable pressure chamber, it is especially adapted for use in connection with a digester similar to that disclosed in my copending application, Serial No. 246,976, in which digester a suitable steam pressure is maintained: continuously, and furfural and other volatile substances are continuously formed and continuously removed from the pentosan-bearing or furfural-yielding material, which latter is continuously supplied to, and after being processed is continuously re-. moved from, the digester or reaction chamber.

It is an object of my invention to provide means for continuously feeding the above-mentioned materials, or others of a similar nature, into and from the digester or autoclave, and at the same time provide a gas-proof seal to prevent the release of the pressure therein.

My invention also contemplates the method of using the material handled as an eflicient gasproof seal during the operation of the device, and the provision of an automatic gas-proof means for retaining the pressure when there is no material passing through the device.

In the manufacture of furfural and similar volatile substances, it is desirable that a suitable acid liquid be thoroughly intermixed with the pentosan-bearing material to be fed into the digester, and my invention also contemplates the method of thoroughly intermixing the material with a suitable moistening fluid and continuously feeding the dampened or'wet mixture into the 0 digester against the comparatively high pressure maintained therein, and removing the residue therefrom without materially reducing the pressure.

For a better understanding of the nature, scope and characteristic features of my. present invention, including the method mentioned, reference may now be had to the following description and accompanying drawings, in which:

Figure 1 is a top plan view of an apparatus embodying one form of my invention, and by. means 5 of which my present process may be practised;

Fig. 2. is a longitudinal sectional view taken on a line corresponding to line-2--2 of Fig. 1;

Fig. 3 is a transverse, sectional view through the feeding chamber and taken substantially on 10 line 3-3 of Fig. 2; I

Fig. 4 is a longitudinal sectional view of the feeding device used for removing, the residue from the pressure chamber;

Fig. 5 is a detail view partially in longitudinal 15 section of the valve and valve operating means, the valve being shown in open operative position;

Fig. 6 is a perspective view of the cutting and loosening knife illustrated in Fig. 4;

Fig. 7 is a side elevation of the valve member, 20 a portion being broken away better to illustrate the fin contour;

Fig. 8 is a rear view of the valve member taken online 88 of Fig. 7, the. valve stem being shown in section;

Fig. 9 is a front end view of the valve member;

Fig. 10 is a vertical, longitudinal section illustrating the use of my invention in connection with a somewhat different form of chamber inlet construction; and

Fig. 11 illustrates a form of feeding device in which the feeding chamber tapers outwardly toward the valve. v

Referring to the drawings in detail, in the embodiment illustrated a horizontally disposed compressing section B is supported on asuitablebase I and provided with a cylindrical impregnating and compressing chamber 2 therein. The compressing chamber communicates with an autoclave or digester C of any suitable construction 40 through a passage 3 in an ingress section 4.

The compressing section B includes a casing comprising a plurality of longitudinal sections 5 secured together and provided with a tubular lining 6. The section is adjacent the mixing tank or oat hull bin A and is arranged to receive oat hulls or similar material therefrom through an ingress passage 1. Inorder that the material and the acid liquid may be mixed in the compressing section, if desired, instead of being previously mixed in the tank A, a supplemental acid tank 8 feeds into the ingress passage 1 through a pipe 8, which latter is provided with a control valve ill. This allows the flow of liquid to be controlled and fed into the mixing chammay be driven ber, simultaneously with the material from the bin A, where it will be thoroughly mixed by a means which will be later described.

The passage 3 in the digester ingress section 4 is normally closed by means of a valve head I I resting against the end of the mixing chamber lining 6. which latter forms a valve seat therefor. The valve head ll is secured to a valve stem I2, which latter is rotatably and slidably mounted in the bearings l3 and H on the base I. A crosshead 15 is slidably mounted on longitudinally disposed rods i6 and forms a thrust bearing for the end of the valve stem l2. The valve is normally held closed by compression springs IT on the rods l6 and bearing against the cross-head IS. The valve is normally held closed and the compression of the springs i1 and the consequent pressure of the valve head H against the valve seat may be adjusted by means of nuts 18 on the rods l6. During the operation of the machine the valve head II is rotated at a suitable speed, from any suitable power source, the operation being controlled by abelt I3 and tight and loose pulleys 2i and 20, respectively, on the valve stem l2. It will be noted that when the valve ll is seated, it will be stationary as the belt is then on the loose pulley 20, and when the valve is opened by the pressure of incoming material, it will be rotated by the engagement of the belt IS with the tight' pulley 2|.

The compressing section B is provided with an interrupted screw conveyor 22 therein, comprising a shaft 23 mounted in a bearing 24 and extending into the impregnating and compressing chamber in axial alignment therewith.' A gear 25 is secured to the shaft 23 by which it from any suitable source of power. A thrust bearing 26 prevents longitudinal movement. Spiral ejector flights 21 are removably mounted on the shaft 23 and rigidly clamped thereon by means of a screw 28. When the moistened material is fed through the inlet passage 1 to the compressing chamber, it will be forced toward the valve H by the conveyor flights 21. Inwardly extending baflle plates 29 are supported by the casing sections as illustrated in Figs. 2 and 3, and extend inwardly and adjacent the shaft 23. These baflie plates prevent the mate- ,rial from rotating with the conveyor. The conveyor blades 21 force the material in the compressing chamber 2 toward the valve II and cause, in conjunction with the battle plates 29, the material to be progressively compressed to form a moving gas-tight plug adjacent the valve. This compressed plug of material will be pressed against the rotating valve head H until the constantly increasing pressure overcomes the compression springs I1 and the valve head II will be moved away from the valve seat, as illustrated in Fig. 5, to allow the material to be forced into the digester inlet passage 3. The valve will then be automatically rotated by the engagement of the belt IS with the pulley 2| as previously mentioned. The material in the chamber adjacent the valve head is very snugly compressed and forms a moving gas-tight plug which effectively overcomes the pressure maintained in the digester or autoclave C.

In order to break up the material of the plug so that it will pass around the rotating valve head and into the passage 3, the valve head is provided with a spiral center bit point 30, and outwardly extending lugs 3| having spirally disposed cutting edges 32. The axially disposed spiral bit point 30 and the cutting lugs 3| efiectively break up the end of the compressed plug of material, and this loosened material is forced around the valve head I l and into the passage 3 by the pressure of the material following. The valve head H is also provided with spirally disposed flns 33 arranged to push the loosened material through the passage 3 to a position where it will drop by gravity into the digester C. If the feeding of the material to the mixing chamber is interrupted, the resultant reduced pressure against the valve head II will allow it to reseat and retain the pressure in the digester chamber.

In the form shown in Fig, the ingress passage to the digester is directly in alignment with the face of the valve head l2, so that loosened material drops directly into the digester.

In Fig. 4 is illustrated the output means for removing the residue from the digester. This output feeder D is similar in construction to the input device B just described and, in fact, they may be used interchangeably if desired. However, a restricted outlet opening is desirable, and

a funnel-shaped portion 34 is secured to the feeder. and having a restricted outlet passage 340. through which the residue is discharged into a chamber 35, where it drops by gravity to a conveyor 36, by which it is carried away.

In using the feeder as an output device, the ingress passage 1 is arranged to receive the spent hulls or residue from the digester and from which they will fall by gravity into the conveying and compressing chamber 2, where they are compressed to form a moving plug to prevent the direct escape of live steam or other pressure. A propeller-shaped cutting knife 31 in the form of a propeller is secured to the end of the shaft 23 and provided with cutting edges 38 (see Fig. 6).

The purpose of the cutting knife in the outlet feeder is to break up the outer end of the moving plug in the chamber 2 so that the material may enter the funnel-shaped member 34 and pass through the restricted passage 34a.

In the output device, the chamber 2 is at cooking pressure, while the chamber 35 is at atmospheric pressure. A large inlet passage 1 is necessary to prevent bridging of the material at the entrance, and the restricted outlet passage 34a. is provided, as the velocity of the material at the point of contact with atmospheric pressure is very high. Since the velocity of the material is so great, large quantities can be discharged through a small opening. If the same size opening extended through to the input end of this feeder, the difficulty of bridging might result. The spent hulls are discharged around a valve 39, which is similar to the inlet feeder valve II and is secured to the stem l2.

The spent hulls as discharged give up the heat therein contained, in the form of steam. This steam is given up so quickly that the hulls have the appearance of being blown through the valve, but measurements of the steam given off show that the spent material on discharge yields approximately the theoretical amount of steam.

In feeding the material, it is desirable to control the rate of discharge, since too rapid a discharge will very quickly remove the material from the compressing chamber and insufficient material will be left therein to form a gas-tight plug. It will be apparent that a rate of discharge should be maintained corresponding to the pressure and the rate at which it is desired to feed the material through the digester. In order to 2,059,435 control the rate of discharge, an, adjustable with the threaded shaft 4|. The'shaft 4| may bemanually rotated by any suitable means, such as the crank 45 for moving the chain 46 on the sprockets 41 and 48.

It is evident that, through the mechanism just described, the sleeve 42 may be adjusted to cause the compression springs IT to be effective only when the valve head 39 moves the desired distance from the valve seat. The rate of discharge will therefore be relative to the adjusted position of the valve head.

The relative horse power developed by a motorused for operating the feeding device will indicate when the plug has been formed. Another method is to insert a stirring device in the feeding chamber and the material is allowed to build up until the stirring device does not turn freely.

The difference in the appearance of the discharge will indicate whether or not a suitable plug is maintained, or a drop in pressure may be noted on a suitable pressure recording instrument.

The above noted considerations indicate the desirability of a suitable discharge control means.

In the embodiment shown in Fig. 4, the plug of material may be allowed to extend to any desired distance beyond the valve seat before the pressure of the springs l1 becomes effective, and

the material broken up and removed by the valve head will drop directly to the conveyor 36.

It will be understood from the above descrip- In operation, the material falls by gravity from the tank or bin A into the input feeder B where it is mixed, impregnated and compressed into a moving gas-tight plug and passed into the digeste'r or autoclave C by being broken up by the rotating valve and dropping therein by gravity. The furfural is there removed under suitable conditions of steam pressure and temperature maintained therein, and the residue falls by gravity into the output feeder D, in which it is again compressed to a moving gas-tight seal and broken up and discharged through the restricted passage 34a and around the valve 39 into atmospheric pressure, where it drops by gravity to the conveyor 36 to be disposed of as desired. In the modified form shown in Fig. 11, the chamber 2 of the feeder tapers outwardly slightly at 49 to allow the end of the plug to expand and loosen tion that the feeding device maybe used either P Seal gester against substantial superatmospheric pressure maintainedtherein, which comprises impregnating the material with a dilute acid and continuously feeding said material to the digester in the form of a continuously renewed highly compressed gas proof plug formed at the ingress of said digester to constitute thereat a seal against the escape of the pressure from the digester, and continuously breaking up the inner end of the plug to allow the material to enter the digester. j

2. The method of continuously feeding solid,

pulverulent, furfural-yielding material into a digester againstsubstantial superatmospheric pressure maintained therein, which'comprises moistening said material, then compressing the material into a highly compressed gas-proof plug at the ingress of the digester and then forcing said plug into the digester through said ingress whereat said plug constitutes a gas-proof seal in the form of a continuously renewed and continuously moving plug, and continuously breaking up the inner end of said plug.

3. In combination with a digester for pulverulent material wherein a superatmospheric pressure is continuously maintained, said digester having a gas-tight ingress passageway, of a mechanism for continuously feeding said pulverulent material into the digester through the said passageway which comprises a housing that communicates at its inner end with said passageway, means in said housing for continuously forming said material into a compacted solid plug to provide continuously within said housing adjacent to the said ingress passageway of the digester a gas-proof seal that precludes the release pressure from the digester and for continuously replenishing the plug at its outer end with fresh material that likewise is densely compacted into the plug, and means for continuously removing some of said material from the compactedplug and delivering the same to the digester while keeping the major portion of said plug intact as a gas- 4. A feeding device for continuously feeding solid pulverulent material into a digester against substantial superatmospheric pressure continuously maintained therein,,comprising means for continuously forming said material into a compacted solid plug at the ingress to said digester to constitute a gas-proof seal thereat and for constantly renewing said gas-proof seal with additions thereto of said material, means for removing continuously some of said material from said seal for use in said digester'whil'e' keeping said plug intact at said ingress as a gas-proof seal, said removing means forming automatically a, gas-proof mechanical valve for said ingress when the said plug is not effective to seal the pressure within the digester.

5. A feeding device for continuously feeding solid pulverulent material into a digester against substantial superatmospheric pressure continuously maintained therein,,comprising.means, for continuously forming said material into a compacted solid plug at the ingress to said digester to constitute a gas-proof seal thereat' and for constantly renewing said gas-proof sealing plug with additions thereto of said material, a gasproof mechanical valve normally closing said ingress to preclude escape of pressure from said digester, the pressure of said plug after being formed operating to automatically open said valve, and means for breaking material from said plug for entrance into said digester, said forming and renewing means maintaining said gas-proof sealing plug intact to seal the pressure within the digester.

6. In combination with a digester for pulverulent material wherein a superatmospheric pressure is continuously maintained, said digester having at least one gas-tight passageway, a movable gas-proof valve normally closing said passageway, of a mechanism for continuously handling said pulverulent material comprising a housing adjacent to and communicating with said passageway, means in said housing for continuously compressing said pulverulent material into a highly compacted gas-proof plug against said valve to open it and to project said plug into said passageway to seal continuously the latter against the release of pressure within the digester and for continuously replenishing said plug with fresh pulverulent material, said valve continuously breaking up said plug at its end that has advanced through said passageway.

7. The method of continuously feeding solid, pulverulent, furfural-yielding material through a chamber having a substantial superatmospheric pressure, which comprises impregnating the material with a dilute acid and continuously feeding the material to the pressure chamber in the form of a continuously renewed highly compressed gasproof plug that is held against rotation to seal the chamber at the ingress passageway against release of pressure, and continuously breaking up the plug under the chamber pressure, then feeding the residue from the chamber in the form of a highly compressed gas-proof plug that is held against rotation to seal the chamber at the egress passageway against release of pressure and continuously breaking up the last named plug under atmospheric pressure.

8. The method of continuously feeding solid, pulverulent, furfural-yielding material through a digester wherein a substantial superatmospheric pressure is maintained which comprises moistening the material and compressing it under atmospheric pressure into the form of a continuously renewed highly compressed gas-proof plug that is held against rotation to seal the digester at the ingress passageway against release of pressure, feeding the plug continuously into the digester, and continuously breaking it up under the digester pressure, then compressing the residue under the digester pressure into the form of a continuously renewed, highly compressed gasproof plug that is held against rotation to seal the digester at the egress passageway against release of pressure, feeding the last named plug continuously out of the digester, and breaking it up under atmospheric pressure.

9. The method of continuously feeding compressible, pulverulent, furfural-yielding material into a digester against a relatively high pressure maintained therein which comprises impregnating the material with an acid liquid, then continuously and progressively compressing said material into a dense, highly compacted, gas-tight plug at the ingress to said digester to form a pressure sea] at said ingress, continuously forcing the inner end of said plug into said digester while continuously replenishing the plug at its outer end with fresh material that is likewise compacted, and continuously breaking up the plug at its inner end so that said material is delivered to the digester in uncompacted form.

10. The method of continuously feeding pulverulent solid material into a digester against a relatively high pressure continuously maintained therein which comprises dampening the material, then continuously and progressively compressing said dampened material into a dense, highly compacted, gas-tight plug at the ingress to said digester to form a pressure seal thereat, maintaining said plug against rotation while continuously forcing the inner end thereof into the digester wherein it is dissociated, and continuously replenishing said plug at its outer end with fresh dampened material that is likewise densely compacted to keep an intact plug continuously at the ingress of said digester.

11. The method of continuously feeding pulverulent solid material into a digester against a relatively high pressure continuously maintained therein which comprises dampening the material, then continuously and progressively compressing said dampened material into a dense, highly compacted, gas-tight plug at the ingress to said digester to form a pressure seal thereat, maintaining said plug against rotation while continuously forcing the inner end thereof into the digester, continuously replenishing said plug at its outer end with fresh dampened material that likewise is densely compacted to keep an intact plug of said material continuously at the ingress of said digester, and continuously breaking up the plug at its inner end so that said material is delivered to the digester in uncompacted form.

12. The method of continuously feeding compressible, pulverulent, solid material into a container wherein a relatively high pressure is continuously maintained which comprises compressing said material into the form of a dense, highly compacted, gas-tight plug which continuously seals said container at its ingress against the release of the pressure therein, continuously forcing the inner end of said plug into said container while continuously replenishing the plug at its outer end with fresh material that likewise is densely compacted to keep an intact plug of said material continuously at the ingress of said digester, and continuously breaking up the inner end so that said material on delivery into said digester resumes substantially its initial loosened state.

13. The method of continuously feeding compressible, pulverulent, solid material into a container wherein a relatively high pressure is continuously maintained which comprises compressing said material adjacent the ingress of the container into the form of a dense, highly compacted, gas-tight plug, maintaining said plug against rotation thereby effectively sealing said container at its ingress against the release of a pressure therein, and continuously forcing the inner end of the plug into said digester wherein it is dissociated while continuously replenishing the plug at its outer end with fresh material that likewise is densely compacted, thus keeping an intact gas-tight plug at all times at the ingress to said container.

14. The method of continuously feeding compressible, pulverulent, solid material into a digester wherein a relatively high pressure is continuously maintained which comprises impregnating said material with a liquid, then compressing said material adjacent the ingress of the digester into a dense, highly compacted plug that is held against rotation thereby effectively sealing said digester at its ingress against the release of the pressure therein, continuously forcing the inner end of said plug into said digester while continu-- ously replenishing the plug at its outer end with impregnated fresh material that is likewise densely compacted whereby a gas-tight seal is continually maintained at said ingress while the material is being fed into the digester, and then continuously breaking up the plug at its inner end so that said material is delivered to the digester in an uncompacted state.

15. The method of processing pulverulent, solid, furfural-yielding material which comprises impregnating said material with an acid liquid, continuously feeding such material into a digester wherein a substantially superatmospheric pressure is continuously maintained, said feeding operation comprising continuously and progressively compressing said dampened material into a dense, highly compacted, gas-tight plug at the ingress to said digester to form a pressure seal thereat, maintaining said plug against rotation while continuously forcing the inner end thereof into the digester wherein it is dissociated, and continuously replenishing said plug at its outer end with fresh dampened material that is likewise densely compacted'to keep an intact plug continuously at the'ingress of said digester, then processing said material within said digester, and continuously withdrawing the spent material from the'digester through its egress, the withdrawing operation comprising continuously and progressively compressing such spent material into a dense, highly compacted, gas-tight plug at the egress of said digester to form a pressure seal thereat, maintaining said plug against rotation while continuously forcing the outer end thereof from the digester, and continuously replenishing said plug at its inner end with spent material that is likewise densely compacted to keep an intact plug continuously at the egress of said digester.

16. An apparatus for continuously processing loose solid material which comprises a digester wherein superatmospheric pressure is continuously maintained, means for continuously feeding said loose material into said digester through an ingress thereof, said means continuously forming said material at said ingress into a compacted gas-proof plug that seals said ingress against the release of pressure and continuously replenishing said plug with fresh material as said plug is advanced into said digester, a mechanical valve that normally seals said ingress against the release of pressure from said digester, said valve being automatically unseated from said ingress by the pressure of the said plug as it advances through said ingress, and means to dissociate the inner end of said plug to deliver the material in uncompacted form to the digester.

1'7. An apparatus for continuously processing loose solid material which comprises a digester wherein superatmospheric pressure is continuously maintained, means for continuously feeding said loose material into said digester through an ingress thereof, said means continuously forming said material at said ingress into a compacted gas-proof plug that seals said ingress against the release of pressure and continuously replenishing said plug with fresh material as said plug is advanced into said digester, means for holding said plug against rotation as the same is advanced into the digester, a mechanical valve that normally seals said ingress against the release of pressure from said digester, said valve being automatically unseated from said ingress by the pressure of the said plug as it advances through said ingress, and means to dissociate the inner end of said plug to deliver the material in uncompacted form to the digester.

18. An apparatus for continuously processing loose solid material which comprises a digester wherein superatmospheric pressure is continuously maintained, means for impregnating said loose material with a liquid and for continuously feeding said loose material into said digester through an ingress, said means comprising an interrupted screw conveyor and spaced baflies interposed between threads of said conveyor for continuously forming said material at said ingress into a compacted, non-rotatable, gas-proof plug that seals said ingress against the release of pressure and for continuously replenishing said plug with fresh impregnated material as said plug is advanced into said digester, a mechanical spring-pressed valve that normally seals said ingress against the release of pressure from said digester but which is automatically un seated from said ingress by the pressure of said plug as it advances through said ingress, and means to dissociate the inner end of said plug to deliver the material in uncompacted form to the digester.

19. An apparatus for continuously processing loose solid material which comprises a digester wherein superatmospheric pressure is continuously maintained, means for impregnating said material with a liquid, means for continuously feeding said loose impregnated material into said digester through an ingress, said feeding means comprising an interrupted screw conveyor and spaced baflies for continuously forming said material at said ingress into a compacted gas-proof plug that seals said ingress against the release of pressure and for continuously replenishing said plug with fresh material as the said plug is advanced into said digester, an independently operated spring-pressed valve that normally seals said ingress against the release of pressure from said digester, said valve being automatically unseated from said ingress by the pressure of the said plug as it advances through said ingress, and means mounted on said valve to dissociate the inner'end of said plug to deliver the material in uncompacted form to the digester.

20. An apparatus for continuously feeding solid pulverulent material into a digester against a substantially superatmospheric pressure continuously maintained therein which comprises means for continuously forming at the ingress passageway to said digester a gas-proof seal of said material in the form of a highly compacted non-rotatable plug; and means for continuously removing portions of the said material constituting said plug and feeding the material to the digester, said first means continuously replenishing the plug by delivering thereto in highly compacted form fresh pulverulent material on one side thereof as the plug is being constantly depleted on the other side thereof when the material is fed to the digester.

HAROLD J. BROWN'LEE.

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