US1908691A - Pulp control apparatus and method - Google Patents

Description

May 16, 1933. H, s, CGE 1,908,691

PULP CONTROL APPARATUS AND METHOD Filed Deo. 10, 1928 2 Sheets-Sheet 1 A TTORNE YS May R933. H, s, COE

PULP CONTROL APPARATUS AND METHOD Filed Dec. l0, 1928 2 Lsheets-sheet 2 INVENTOR Hoff/5o 5 Coe A TTORNE YS Patented May 16, 1933 STATES PATENT OFFICE HARRISON S. COE, F PALO ALTO, CALIFORNIA PULP CONTROL APPARATUS AND METHOD Application led December 10, 1928. Serial No. 325,100.

the control of ore pulp being removed in thickened state from thickening devices, or

in the control of sandy material being removed from ore pulp by a centrifuge.

It is a general obJect of this invention to devise a novel means and method of the gen- 2@ eral character described above which will provide a continuous supply of pulp of desired characteristics.

It is a further object of this invention to devise a means and method of effecting con- .25 trol of pulp and which takes into account the iiuidity'or viscosity of the pulp as well as its specific gravity.

It is a further object of this invention to devise a system and method of control of pulp whereby an excess of thickened pulp is removed from the thickener or separator and a controlled portion is returned to regulate the character of the pulp removed fromthe It is a further object of this invention to devise a novel form of testing apparatus and method of operating the same which is operated responsive to the specific gravity of a continuous iiow of pulp.

Further objects of the invention will ap. pear from the following description in which I have set forth the preferred embodiment of my invention. It is to be understood that the appended claims are tobe accorded a 15 range of equivalents consistent with the state of the prior art.

Referring to the drawings: Figure 1 is a diagrammatic view illustrating one form of my apparatus in side elevation.

Fig. 2 is a view similar to Fig. 1 showing a modified form of apparatus.

Fig. 3 is a diagrammatic view showing the apparatus of Fig. 1 combined with a pulp thickener.

Fig. 4 is a diagrammatic view showing the apparatus of F ig. 1 employed with a centrifuge.

Fig. 5 is a diagrammatic view showing a further modified form of testing apparatus. The nature of my invention can best be understood by reference to the apparatus shown in the drawings. Referring to Figure 1 a receptacle 11 is provided for receiving a continuousA fiow of pulp. I prefer that this receptacle be formed with an upper cylindrical portion and a lower conical portion as shown. Pulp is introduced into receptacle 11 as by means of conduit 12 and is permitted to discharge thru conduit 13. Conduit 13 70 preferably communicates with the lower portion of receptacle 11, and for this purpose I have shown another conduit 14 extending centrally of receptacle 11 and communicating with conduit 13. The lower end of conduit section 14 is in communication with the lower portion of receptacle 11, while the upper end of conduit 14 is provided with a removable closure 16 to facilitate removal of material after a shut down.

The entire receptacle 11 is preferably supported by suitable balancing means and is free to move a certain amount in a. vertical direction. As an example of suitable balancing means, I have shown a beam 17 fulcrumed 85 as at 18. Receptacle 11 is pivotally supported by one of this beam, as is indicated by the pivot connection 19, while controlled balancing forces are applied to the other beam end. For example I have shown removable counterweights 21 and a slidable beam weight 22. Swinging movement ofthe beam is limited by stop members 23.

In conjunction with conduit 13 I provide means whereby distribution of pulp flowing 95 from receptacle 11 is determined in accordance with the position of this receptacle and conduit 13. @ne convenient form for such means is provided by a pair of chambers 26 and 27 separted by a diaphragm 30. Chamma ber 26 is hereinafter referred to as the final discharge chamber, while chamber 27 is referred to as the return chamber. These chambers are connected to conduits 28 and 29 respectively. Diaphragm 30 is so located with respect to the opening of conduit 13, that when receptacle 11 is in a lowered position flow of pulp from the receptacle is directed into chamber 26, when the receptacle is in raised position pulp passes over the upper edge of diaphragm 30 and is received in chamber 27, and when in an intermediate position flow is split between chambers 26 and 27.

To explain in a preliminary way operation of the apparatus shown in Fig. 1, it will be presumed that pulp of a given specific gravity is being introduced into receptacle 11 thru conduit 12 at a constant rate. The level of pulp within the receptacle rises to a point indicated by dotted line 1, at which the gravity pressure head of the pulp is sufficient to cause discharge thru conduit 13 at a rate equal to the rate of inflow thru conduit 12. Assuming that beam 17 with its weight is set for pulp of this specific gravity, then the weight of receptacle 11 and its associated parts and the weight of the pulp within the same, is suflicient to balance the beam 1n an intermediate position. In such position the discharge of pulp from conduit 13 is split by diaphragm 30 -so as to flow in both chambers 26 and 27. If the specific gravity of pulp entering thru conduit 12 decreases, the Weight of the mass of pulp within receptacle 11 accordingly decreases andthe receptacle is lifted by beam 17. Conduit 13 is then caused to deliver all or a substantial portion of the pulp to the chamber 27. If the specific gravity of pulp should increase, the weight of pulp Within receptacle 11 is accordingly increased so that the receptacle is lowered below its intermediate balanced position so that all or a greater portion is delivered to chamber 26. Thus the proportionate distribution to chambers 26 and 27 is made dependent upon the specific gravity of pulp introduced into the receptacle thru conduit 12.

In the above example it is presumed that the viscosity of the pulp remains practically constant. It is characteristic of my apparatus however that it can be made responsive to changes in viscosity or fluidity as well as to changes in specific gravity. For example assuming that the viscosity of the pulp increases or that the fluidity decreases, the greater resistance to flow requires a greater gravity pressure head of pulp within the receptacle 11, so that the level of the pulp rises to a new level indicated for example by the dotted line 2. At this new level equilibrium is again established between the inflow and outflow rate of pulp thru receptacle 11` but since there is a larger volume of pulp within the receptacle` beam 17 is overhalanced, and conduit 13 is lowered to `effect a greater proportional discharge into chamber 26 than to chamber 27 Conversely a lowering in the viscosity of the pulp causes raising of the receptacle from its intermediate position to effect a greater proportionate discharge of pulp into chamber 27 than to chamber 26.

In many applications of my apparatus it is desirable to control the pulp according to its viscosity as well as according to its specific gravity. A change in viscosity may be accompanied by change in specific gravity, or the specific gravity may remain constant and the viscosity vary due to changes in the percentage of colloids. It is frequently desirable to modify the control effected by a change in viscosity. One manner in which this can be accomplished is by adjusting the area of the receptacle 11 in the vicinity of level 1. For example I have shown a member 31 positioned within the upper portion of receptacle 11 in fixed relationship to the same. This member reduces the effective area of the receptacle in the vicinity of level 1, and thus tends to correspondingly reduce the change in weight of pulp in receptacle 11, for a given change in the level of the pulp occasioned by the change in viscosity. By modifying the control in this manner, it is possible to secure a pulp of the desired characteristics when the apparatus of Fig. 1 is employed in the system to be presently described.

In Fig. 2 I have shown an apparatus similar to that of Fig. 1, but which has provision for eliminating control according to the viscosity or fluidity of the pulp. In this instance a large auxiliary conduit 32 is provided for removing a continuous overflow from receptacle 11. In this case the amount of overflow varies according to a change in fluidity, but the level of pulp within the receptacle remains practically constant. The discharge opening of overflow conduit 32 is preferably positioned in cooperative relationship to diaphragm 30, so that its discharge is split for the intermediate balanced position of receptacle 11.

The apparatus of Fig. 5 operates similar to that of Fig. 2 in that a change in fluidity or viscosity of pulp introduced into receptacle 11 does not affect the pulp distribution. In this case receptacle 11 is divided into two sections by an upstanding diaphragm or wall 20. these sections being connected yat the lower portion of the container. Pulp is introduced into the receptacle at one side of diaphragm 2O and removed from the other side thru the large overflow conduit 113. In operation the total volume of pulp within the receptacle remains practically constant irrespective of changes in viscosity.

In shutting down the apparatus of Figs. 1. 2 or 5. material may accumulate in receptacle 11 which will not flow out when the stantially below the desired value.

apparatus is again put in operation. To effeet automatic removal of all material in the event of a shut down, I have shown a .valve 25 which is normally closed but which 1s opened by engagement with stop 35. When flow of pulp into the receptacle 11 is discontinued, the receptacle moves upwardly a sufficient distance to cause valve 25 to engage stop 35 and thus cause automatic discharge of the remaining pulp.

In Fig. 3 I have shown a complete control system in which the apparatus shown in Fig. 1 is incorporated with a pulp thickening apparatus, indicated by container 33. Conduit 12 is supplied with discharge pulp from vessel 34 which in turn is in communication with a suitable pulp pump 36. The discharge from container 33 is connected to the intake of pump 36 thru conduit 37. Vessel 34 together with conduit 28, are connected to the final discharge line 38. Chamber 27 is connected to receptacle 33 thru conduit 29. The terms discharge and discharge pulp are used in this specification and the appended claims to designate the denser fraction of the pulp removed from container 33.

In explaining the operation of the system of Fig. 3, it is presumed that the apparatus is set for the ultimate removal of pulp of a certain specific gravity and that the thickened pulp removed from thickener 33 is sub- Receptacle 11 is therefore unbalanced and pulp is discharged therefrom into chamber 27 from which it is returned to conduit 37 or to the thickener thru conduit 29 as shown. Return of substantially all the pulp diverted thru receptacle 11 results in an increase in the specific gravity of pulp removed from the thickener thru conduit 37. When the specific gravity increases to the desired value, receptacle 11 balances in its intermediate position and the discharge of pulp from this receptacle is split between chambers 26 and 27 That portion received by chamber 26 is rw-,mved from the system thru conduit 38, together with pulp removed from vessel 34. Small changes in the specific gravity result immediately in changes in the amount of pulp received by chamber 27, thus immediately reacting on the thickener 33 and effecting a compensating change in the speciic gravity of the discharge pulp. If the specific gravity becomes too dense, practically all pulp from receptacle 11 is discharged into chamber 26 and delivered to conduit 38, and practically no pulp is returned to thickener 33. It is characteristic of the method of operation of this system that the. discharge of pulp from thickener 33 occurs at a rate substantially greater than the rate of removal of pulp from conduit 38. rThe difference between the rates of removal from receptacle 33 and the rate of removal from the system thru conduit 38 represents the pulp returned thru conduit 29 to the thickener. As has been previously explained, the amount of pulp returned is under continuous and automatic control of the specific gravity testing apparatus. For convenience I prefer not to pass all of the pulp thru receptacle 11 although such a mode of operation is possible. In practice only a large enough fraction of the pulp is passed thru the testing apparatus to effect proper control of the pulp removed between the desired maximum and minimum limits.

It is apparent that in place of the thickener 33 of Fig. 3, I can utilize any apparatus which has a discharge of pulp and which will retreat pulp returned thru conduit 29. For example in Fig. 4 I have shown diagrammatically a centrifuge separator 41 incorporated in a system similar to that of Fig. 3. Centrifuge 41 is represented as having a pocket 42 from which the discharge pulp is conveyed to receptacle 11 thru conduit 37. From receptacle 11 the pulp is either discharged into chamber 26 from which it is removed from the system, or is discharged into chamber 27 and returned to centrifuge 41l thru conduit 29.

I claim:

1. In an apparatus of the class described, a receptacle receiving a continuous flow of fluid pulp, said receptacle being arranged to permit movement of the same, means for applying force to said receptacle to maintain the same in a balanced position dependent upon the nature of its contents, and two chambers serving to. receive flow of pulp from said receptacle in accordance with its position.

2. In an apparatus of the class described, a receptacle receiving a continuous flow of fluid pulp, said receptacle being arranged to -permit vertical movement of the same, means for applying upwardly directed force to said receptacle to maintain the same in a balanced position dependent upon the nature of its Contents, and two chambers serving to receive fiow of pulp from said receptacle dependent upon the position of the same.

3. In an apparatus of the class described, a receptacle receiving a continuous flow of fluid pulp, said receptacle being arranged to permit vertical movement of the same, means for applying upwardly directed force to said receptacle to maintain the same Ain a balanced position dependent upon the nature of its contents, a plurality of chambers for rc ceiving flow of pulp from the receptacle and conduit means'movable responsive to movements of said receptacle for directing dow from said receptacle into either one or both of said chambers.

4. In an apparatus of the class described, a receptacle receiving continuous flow of fiuid pulp, said receptacle being arranged to permit vertical movement of the same,

5. In an apparatus of the class described,

a receptacle receiving continuous flow of fluid pulp, said receptacle being arranged to permit vertical movement of the same, means for applying upwardly directed force to said receptacle to maintain the same in a balanced position dependent upon the nature of its contents, conduit means movable responsive to vertical movement of the receptacle for conducting How of pulp from the receptacle, a pair of chambers for receiving flow of pulp from the conduit means, and means for directing the flow from said conduit means into either one or both of said chambers dependent upon the position of the conduit means.

6. In an apparatus of the class described, a. receptacle receiving continuous flow of fluid pulp, said receptacle being arranged to permit vertical movement of the same,

means for applying upwardly directed force to said receptacle to maintain the same in a balanced position dependent upon the nature of its contents, conduit means movable responsive to vertical movement of the receptacle for conducting flow of pulp from the receptacle, a pair of chambers for receiving How of pulp from the conduit means, and a diaphragm for directing the flow from said conduit means into either one or both of said chambers dependent upon the position of the conduit means and said receptacle.

7. In an apparatus of the class described, means for thickening fluid material, two fluid material receiving chambers, one of which is connected with said thickening means for effecting return of deliveredthickened material to the same, and means for' effecting a proportional distribution of thickened material delivered from said thickening means into said chambers in accordance with the lWeight of a given volume of the same, said last means being so adapted that a substantial amount of the thickened material delivered, but not all, is returned to said thickening means when the specific gravity7 of the delivered material is of a desired value.

8. In a device for controlling the specific gravity of fluid pulp from a system which includes a separating or thickening apparatus,

said device comprising means for establishing a continuous discharge of pulp from said apparatus at a rate normally greater than the rate of removal of pulp from the system, means for diverting a portion of the pulp 55 from the discharge at a constant rate, means for removing the remaining pulp from the system, returning means for conducting substantially all of the diverted pulp in substantially the saine condition as when discharged from said apparatus back to said apparatus when the specific gravity of the diverted pulp is below a given minimum value, said returning means also being effective to return a controlled portion ofthe diverted pulp to the apparatus when the specific gravity is between given maximum and minimum values, means for removing the remainder of the diverted pulp from the system, and means for testing the specific gravity of said diverted pulp and delivering it to said returning means in accordance with the specic gravity of said diverted pulp.

9. A method of controlling the specific gravity of Huid pulp from a system which includes a separating or thickening apparatus comprising establishing a continuous discharge of pulp from said apparatus at a rate normally greater than the rate of removal of pulp from the system, discharging a portion of the pulp, diverting the remainder of the pulp at a constant rate, testing the specific gravity of the diverted pulp, returning substantially all of the diverted pulp to the apparatus when the specific gravity is below a given minimum value, returning a controlled portion ofthe diverted pulp to the apparatus when the specific gravity is between maximum and minimum values, the remaining portion being diverted from the system, and removing substantially all diverted pulp from the system when the specific gravity is above said maximum value, the pulp returned being in substantially the same condition as when discharged from said apparatus.

1n testimony whereof, I have hereunto set my hand.

HARRISON S. COE.

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