Title:
Digesting method and apparatus
United States Patent 2072086


Abstract:
My invention relates to a digesting method and apparatus, and more particularly to a safety device which will prevent "blow-backs". In my co-pending application, Serial No. 581,636, filed December 17, 1931, I have shown a digesting method and apparatus wherein cellulose bearing material is...



Inventors:
Roza Sr., Joaquin Julio DE. LA.
Application Number:
US75568734A
Publication Date:
03/02/1937
Filing Date:
12/03/1934
Assignee:
ROZA CORP DE
Primary Class:
Other Classes:
137/488, 162/237, 200/81R
International Classes:
D21C7/16
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Description:

My invention relates to a digesting method and apparatus, and more particularly to a safety device which will prevent "blow-backs".

In my co-pending application, Serial No. 581,636, filed December 17, 1931, I have shown a digesting method and apparatus wherein cellulose bearing material is digested in a zone maintained under heat and pressure by the material being charged to the digesting zone in and of itself. This is accomplished by ramming the material through an elongated, converging passageway in the form of a compressed cork. The ramming means is a reciprocating plunger or piston. If for any reason the pressure in the digesting zone should be increased or the material being charged form a cork of insufficient density, conditions may be such that the material being charged will be blown backwardly and out of the charging hopper. This may be termed a "blow-back".

One object of my invention is to provide a method of charging material to a digesting zone in which the material itself acts as a closure for the digesting zone and in which "blow-backs" are precluded.

Another object of my invention is to provide automatic means for insuring that the material being charged to the digesting zone is of sufficiently high density.

Another object of my invention is to provide automatic means for eliminating "blow-backs".

Other and further objects of my invention will appear from the following description.

In the accompanying drawing which forms part of the instant specification and which is to be read in conjunction therewith, and in which like reference numerals are used to indicate like parts in the various forms; Figure 1 is a diagrammatic view, partly in section, of a portion of the charging end of a digester fitted with one form of apparatus of my invention, and capable of carrying out the process of my invention.

Figure 2 is an enlarged view, partly in section, of a portion of the control assembly of my inventlon.

Figure 3 is an enlarged sectional view of a detail.

Figure 4 is a diagrammatic view, partly in section, similar to Figure 1, showing a portion of the Inlet end of a digester fitted with another mode of carrying out my invention.

Figure 5 is a sectional view taken on the line 5-5 of Figure 4.

Figure 6 is a plan view of the valve shown in $g Figures 4 and 5.

Figure 7 is a fragmentary, sectional view taken on the line 7-7 of Figure 6.

In general, my invention contemplates the provision of a shutoff means between the charging hopper and the digesting zone, together with means for constantly testing the density or compactness of the advancing closure plug of charging material, the construction being such that when the density falls below a predetermined point, the closure means is automatically operated. The arrangement, further, operates to open the closure means when the density again reaches a predetermined point.

More particularly, referring now to the drawing, a hopper I is provided, into which the material to be digested, is fed. Hopper I is provided with an annular jacket 2 into which impregnating chemical is supplied through connection 3. A plurality of holes 4 provide communication from jacket 2 to the material passing through the hopper to cylinder 5 in which piston or plunger 6, driven by any suitable means through piston rod 7, is adapted to reciprocate. The material to be digested passes through a converging passageway 8, being compressed therein. Occluded air pressed from the material being digested, escapes through openings 9 into an annular jacket 10 from which it is withdrawn through pipe connection I1. Passageway 8 communicates directly with the passageway 12 of inset 13 around which is movably sealed a sleeve 14. The sleeve 14 is provided with an internal passageway 15 of progressively decreasing cross sectional area. The other end of sleeve 14 is mounted within inset 16.

Suitable packing means 17 and 18 are provided at the respective ends of the sleeve 14. The sleeve and its insets are carried by a section 19 which carries a shaft 20. Mounted upon shaft 20 and keyed thereto for movement therewith, is a lever 21, the lower end of which carries a pin 22. The sleeve 14 is provided with peripheral groove 23 in which the pin 22 is adapted to project. Also keyed to shaft 20 for movement therewith is a second lever or arm 24 which is loaded by spring 25 in such fashion as to tend to rotate the shaft 20 in a clockwise direction. An adjusting screw 26 is provided to vary the compression of spring 25.

Connected to section 19 is section 30 carrying the closure or valve means which is adapted to seal communication between the interior of digester 31 and the passageway leading to the hopper I.

Referring now to Figure 1, section 30 is provided with a cylinder 32 in which a piston 33 is adapted to be housed. Piston 33 is provided with 65 a piston rod 34 which passes through cylinder 32, i through stuffing box 35. The upper end of piston rod 34 terminates in a piston 36 which is adapted to work in cylinder 37. Fluid pressure ports 38 and 39 are provided at the upper and lower portions of cylinder 37.

Arm 24 carries contact points 40 and 41 adapted to contact circuit-makers 42 and 43, respectively.

Circuit-maker 43 is adapted to close the circuit through contact points 44 and 45, while circuitmaker 42 is adapted to close the circuit through contact points 46 and 47.

Electro-magnets 50 and 51 control the position of an armature 52, to which valve stem 53 of control valve 54 is attached. Control valve 54 operates within cylinder 55 into which fluid pressure means such as steam, compressed air or the like, is adapted to enter through line 56. Lines 57 and 58 are provided from control valve cylinder 55, to cylinder 37, while lines 59 and 60 communicate with the exhaust.

In operation of the form of the invention shown in Figure 1, the position of the parts is as shown in the figure. The material to be digested is charged to hopper I, impregnated with a chemical and rammed through converging passageway 28 into a compressed column of material. The density of the advancing column of material being sufficiently great, sufficient frictional resistance will be caused by its movement through the bore 15 of sleeve 14 to move the sleeve 14 to the right against the action of spring 25. This movement of the sleeve 14 in the direction of movement of the material being charged, causes arm 24 to move to the left, causing contact points 40 to move circuit-maker 42 across contact points 46 and 47. When this occurs, current will flow from the positive side 70 of the line through conductor 71, through conductor 72, through contact point 46, through circuit-maker 42, to contact point 47, through conductor 73, through the winding 74 of electro-magnet 51, through conductor 75 to the negative side of the line 76. Current flowing through the winding 74 of electro-magnet 51 will cause the armature to move downwardly so that valve 54 will permit fluid pressure means to pass from line 56 through pipe 58 to the under side of piston 36, moving it upwardly to the dotted line position shown in Figure 1. The fluid medium which was above cylinder 56 will pass through line 57 to cylinder 55, discharging thereinto above valve 54, and will pass through line 59 to the exhaust. When the piston 36 moves upwardly, the valve 33 is moved upwardly into its cylinder 32, and the material to be digested is permitted to pass into the digesting zone. If for any reason the pressure in the digesting zone becomes so great as to overcome the frictional resistance of the advancing plug of material, and tends to move the material to the left against its charged direction of movement, the sleeve 15 will move to the left. If for any reason the density of the charged plug drops so that its frictional resistance from sleeve 15 is such that it can no longer overcome the action of spring 25, the sleeve 15 will move to the left. When the sleeve so moves to the left for either of the above reasons, it carries pin 22 to the left and rotates the shaft 20 in a clockwise direction, thus carrying the upper end of arm 24 to the right, permitting contact member 41 to, move circuit-maker 43 to the position shown in Figure 1, bridging contact points 44 and 45.

When this occurs, current will flow from the positive side of the line 70 through conductor 71 to contact point 44 across circuit-maker 43, to conact point 45, through conductor 71, through the winding 78 of electro-magnet 50, through conductor 79 to conductor 75, and thence to the negative side of the line 76. When current so flows, electro-magnet 51 will be energized, attracting armature 52 upwardly, moving control valve 54 to the full line position shown in Figure 2. In this position, fluid pressure means will flow through line 56 into the cylinder 55 from which it passes through line 57 into cylinder 37 above the piston 36, moving it downwardly into the full line position shown in Figure 1. The fluid medium below the cylinder 36 passes out of cylinder 37 through line 58, into cylinder 55 below valve 54, and thence out of cylinder 55 through line 60 which communicates with the exhaust.

Referring now to Figure 4, a modification is shown in which a different type of valve is employed. A pair of sections 80 and 81 are provided with a pair of enlarged flanges 82 and 83 adapted to be bolted together by bolts 84 to provide a circular recess in which a circular plate 85 is adapted to be housed. Plate 85 is keyed to shaft 86 which enters into the circular space just described through a suitable stuffing box 87. The circular plate 85 is provided with an opening 88 having a sharpened periphery 89, as can readily be seen by reference to Figure 7. Also keyed to the shaft 86 is a lever 90 which is pivoted to a connecting rod 91 which in turn is pivoted to piston rod 34 which is connected to piston 36.

It is believed that the operation of the construction is obvious from the drawing. The central mechanism operates the same as that of Figure 1, and the arrangement is such that when the circuit is made through circuit-maker 43, solenoid 51 will be actuated to permit fluid pressure to pass through line 58, moving piston 36 to the position shown and thus bringing an imperforate portion of the circular valve 85 to a position plugging the passageway leading to the digesting zone 31. When the circuit is closed by contactor 42 across contact points 47 and 46, solenoid 50 will be actuated to move the valve 54 of valve cylinder 55 to the position shown in Figure 2, thus permitting fluid pressure to pass through line 57 and move piston 36 downwardly.

The thrust of the piston communicated to crank R, through connecting rod 91 will rotate the valve 85 to a position in which opening 88 is in alignment with the passageway.

It will be obvious that I have accomplished the objects of my invention. "Blow-backs" are prevented, and it is insured always that the material being charged is at least of the desired density.

It will be understood that cettain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is: 1. In a digesting apparatus having a digesting chamber, an inlet passage to said chamber, means for forcing material to be digested through said passage; a valve in said passage and means in said passage responsive to the density of the material in said passage for controlling said valve. 7,5 2. In a digesting apparatus having a digesting chamber and inlet passage to said chamber, means comprising a reciprocating ram for forcing material to be digested through said passage; a valve in said passage and means responsive to the density of the material in said passage for controlling said valve.

3. A digesting apparatus as in claim 1, wherein said passage is formed in part of progressively decreasing cross-sectional area.

4. In a continuous digesting apparatus having an inlet passage for charging material to be digested thereinto and a valve operable to open and close said passage, means in said passage responsive to the density of the material being charged for closing said valve when the density falls below a predetermined value and for opening said valve when the density is restored to said predetermined value.

5. A method of digesting cellulose-bearing materials including the steps of charging cellulosebearing material in the form of a dense plug of predetermined density through an entrance passage and into a digesting zone maintained at a pressure substantially above atmospheric and controlling the passage of said material through said passage into said zone by the density of the plug in said passage.

6. In a digesting apparatus comprising a pressure digesting chamber, means forming a material conducting passage connected to said chamber, and means for forcing a mass of material through said passage in the form of a dense plug; a density control device comprising means forming a portion of said passage adapted to be displaced by a plug of predetermined density, a valve adapted to be moved into position to close said passage and means operable by said displaceable portion and connected to said valve for closing said valve when the density of said mass of material is insufficient to displace said displaceable portion.

'. Digesting apparatus as defined by claim 6, including resilient means connected to said displaceable portion for yieldingly opposing displacement thereof by said mass.

S. Digesting apparatus as defined by claim 6, including adjustable resilient means connected to said displaceable portion for yieldingly opposing displacement thereof by said mass. 9. In a digesting apparatus having a pressure digesting chamber, means forming a material conducting passage connected to said chamber and means for forcing material through said passage; a density control device comprising a sleeve forming a portion of said passage and adapted for limited movement longitudinally thereof, resilient means connected to said sleeve for yieldingly restraining movement in one direction, a valve adapted to be moved into position to close said passageway and means operable by movement of said sleeve in one direction for closing said valve.

10. Digesting apparatus as defined by claim 9, said last mentioned means being operable by movement of said sleeve in one direction to close said valve and operable by movement of said sleeve in the opposite direction to open said valve.

JOAQUIN JULIO DE LA ROZA, SR. 35