US1940946A - Material control apparatus and method - Google Patents

Description

Dec 26, 1933. E. M. HAMHLTON ET AL.

MATERIAL CONTROL APPARATUS AND METHOD Filed Jan. 1 1929 2 Sheets-Sheet 1 KO N MW "pg/WWW TL E N w EM WAO T s W m MU E.

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UNITED STA PATENT OFFICE A MATERIAL common APPARATUS AND METHOD Edward M. Hamilton, Jackson, and scum E. Woodworth, San Francisco, Calif., assignors to Hamilton, Beauchamp & Woodworth, San

3 Claims.

Our invention relates to regulating apparatus and methods for controlling the flow of materials to be mixed or'introduced one into the other, so

as to produce a mixture or compound from predetermined proportions of each material.

An object of the invention is to provide an apparatus and method of the above character which is capable of operating automatically and continuously as materials to be mixed or compounded is supplied to the same.

A further object of the invention is to provide an apparatus and method of the above character which will be characterized by sensitivity and accuracy.

Another object of the invention is to provide a novel and relatively simple combination of elements for attaining the above objects, which will be practical, eflicient and reliable in operation.

Referring to the drawings:

Figure 1 is a fragmentary view in elevation showing an apparatus incorporating the present invention.

Figs. 2 and 3 show a modified form of a portion of the apparatus shown in Fig. 1, with certain parts in their extreme positions.

Fig. 4 shows a feeding means for dry material which can be embodied in our invention.

The method of our invention can be best understood from a detailed description of our novel apparatus illustrated in the drawings, and its mode of operation. Referring first to Fig. 1, we have shown a vertical receptacle 10, which is relatively tall in proportion to its diameter. This receptacle is open at the top to receive a continuous flowing stream of fluid material, from a source represented by outlet 11. The bottom of receptacle 10 is provided with a discharge outlet 12, provided with a valve 13, and which forms an orifice thru which material in receptacle 10 can continually discharge by gravity.

, Receptacle 10 is movable vertically and is carried by suitable counterbalancing means. Thus the receptacle is shown carried by one end of a beam 14, which in turn is suitably mounted upon a' fulcrum 15. To form a bias counter to the weight of receptacle 10 and the material within the same, we provide a weight 16 which is connected to the other end of beam 14.

. As a part of means for controlling the feeding of another material at a rate controlled according to the positioning of receptacle 10, we have shown a bell crank 1'7 having a fulcrum 18. Operably connected to one end of bell crank 17, as by means of link 19 and lever 20, we have shown a movable rod 21 which is associated with a variable liquid feeding device 22 to be presently described in greater detail. If desired, rod 21 can also connect with a stylus 23 of suitable recording instrument 24, so as to produce upon the recording instrument 24 a suitable graphic go record of the position of beam 14 and the position of receptacle l0, and which when properly calibrated, may be read in terms of the flow of material through receptacle 10. Beam 14 can also be provided with a pointer 25, which moves 5 adJacent a stationary scale 26 from which the rate of flow for any particular instant may be determined.

We may explain at this point that within the range of operation of our apparatus, as fluid material is continuously supplied to receptacle 10,

a body of this material accumulates within receptacle 10, and by virtue of the gravity head so established, a continuous discharge occurs thru outlet 12. With a definite rate of flow into the receptacle, a definite weight of material will be in receptacle 10, to establish a definite head capable of causing a rate of discharge thru outlet 12 equal to the rate of inflow. With an increased rate of flow into the receptacle a greater quantity and a greater head of material is established above outlet 12, to establish a rate of discharge equal to the increased rate of inflow. Likewise with a decreased rate of inflow into the receptacle a lesser head is established above outlet 12, to establish a rate of discharge equal to the decreased rate of inflow. Therefore for changes in the rate of flow into receptacle'm the quantity of material within this receptacle will vary to effect variations in the weight of the receptacle and its contents.

With the simple type of beam illustrated, if the effective counterbias of weight 16 were to have a flxed value, the beam 14 would tip abruptly at a certain point and remain tipped regardless of further increases in the rate of flow in the receptacle 10, and likewise when the quantity of material in receptacle 10 decreased below a certain value, the beam 14 would tip back to the original position and so remain. To obviate such abrupt movements between limiting positions and to effect the result that the receptacle will assume various positions of equilibrium responsive to different rates of flow into the receptacle 10,

the effective counterbias of weight 16 is made automatically variable. Thus as illustrated in the drawing weight 16 is suspended in a buoyant liquid 2'1 so that its effective bias varies as it is moved up and down. To accomplish this we provide a container 28 immediately below and in the no path of travel of the weight 16, so that the latter will be partially submerged. In order to provide against the introduction of any error due to a receding of the liquid 27 as the weight is raised, or an increase in the height thereof as the weight is lowered, we provide in connection with the container 28 an overflow 29 and a continual source of, fluid supply thru the pipe 30. This will maintain the level of the liquid in the container 28 substantially constant at all times. With the weight 16 immersed in the liquid 2'7 in this manner; as the beam 14 oscillates up and down, it raises weight 16 higher out of the enveloping liquid and proportionately increases its pull on beam 14, or it allows the weight to sink deeper therein and thus decrease the pull on beam 14. By such an arrangement beam 14 will assume a condition of equilibrium in accordance with the quantity or weight of material in the receptacle 10 and in accordance with the rate of flow of thematerial into the receptacle.

From the above, it is evident that the position of pointer 25 upon the scale 26, or in other words the position of the beam 14, will be an index of the rate of fiow into receptacle 10. If it were desired to control'the feed of the device 22 in proportion to the weight of material in container 10, this might be done by actuating the bell crank 17 directly by the beam 14, but since the discharge from the outlet 12 will not be in direct proportion to the head of liquid in container 10, some means is preferably provided to compensate for this fact. We have found, with a container such as we have illustrated, having an orifice in its lower portion forestablishing a gravity discharge therefrom, that with a head of 1 foot the discharge through the orifice will be X tons and that when the head of the liquid has been increased to 6 feet the discharge through the orifice 12 will be roughly 2X tons. We have, therefore, in order to control the actuation of the feeding device 22 in direct proportion to the discharge through the orifice 12 rather than in proportion to the weight of the material contained in the container 10, provided a segmental gear or rack section 31 upon the balancing arm 14. This segmental gear portion cooperates With a gear 32 secured upon a shaft 33 which carries a cam 34. This cam 34 is adapted to engage a roller 35 carried upon the bell crank 17 and is of such a contour that the movement imparted to the bell crank 17 will always be directly proportional to the discharge of material through the orifice 12 and, as a result, the feeding device 22 will feed material through its discharge outlet 36 in amounts which will 'be proportional to the amount of material being discharged from the orifice 12. Upon close inspection of the above aspects of our invention as illustrated in Fig. 1, it will be seen that the ratio between the segmental gear 31 and the gear 32 is roughly 6:1, or, in other words, while the pointer 25 is moving through an arc of substantially 30, the gear 32 will.move through an arc of substantially 180, thus effecting a movement of the cam 34 which will cause the roller 35 and the bell crank 17 to move between two extreme positions, one closely adjacent the shaft 33 and the other at a point removed therefrom corresponding to the longest dimension of the cam.

In the modification of this aspect of our invention illustrated in Figs. 2 and 3 of the drawings, we have dispensed with the balancing arm 14 and its attendant mechanism and have substituted therefor a counterbalanc g W ght 36 carried upon a cable 37 which passes over an eccentric drum or sheave 38 and a second sheave 39. The eccentric sheave 38 is so fixed with respect to the cable 37 that, as the container 10 pulls the weight 36 upwardly due to an increase in. the liquids therein, the moment arm of the weight-applied forces will be increased directly in proportion to the increase in weight of material within the container 10 and, since the moment arm of the container 10 is fixed; it will be readily seen that the two will remain in stable equilibrium when there is no. change in weight in the container 10, or, in other Words, since the moment arm of the variable container weight is constant, its effect will be variable weight times constant lever arm; whereas, in the case of the constant weight with its variable lever arm, the effect will be constant weight times variable lever arm. In this particular embodiment of our invention we have dispensed with the segmental gear 31 and its cooperating gear 32 and have mounted a bell crank operating cam 40 directly upon a shaft 41 in fixed relation with the eccent-ric sheave 38 so that as the sheave 38 is turned by reason of the movement of the container 10, the bell crank 17 will be moved, as previously described, to control the actuation of the auxiliary feeding device 22.

In Fig. 2, the container 10 is shown as having a small amount of material therein and, as a resuit, the container has been raised by the weight 36 to a position corresponding to its upper limit. Under these conditions, it will be seen that the moment arms of the applied forces exerted by the weight 36 are at their lowest value; whereas, in Fig. 3, the container 10 is shown as substantially full of material and, as a result, is held down into its lowermost position where it has caused the eccentric sheave 38 to rotate and carry the weight suspending portion of the cable 37 out from the center thereof so as to increase the moment arm of the forces applied by the weight 36. It is believed from the above that this embodiment of our invention will be readily understood and further discussion thereof should therefore not be necessary.

The particular variable material feeding device 22 illustrated in this modification of our invention is known as the Kraut liquid feeder, which is the subject of U. S. Patent 1,416,840, dated May 23, 1922. This device comprises a cylinder 41 having a raised triangular portion 42 which revolves horizontally in a bath of the liquid to be delivered thereby. The cylinder 41 is driven by any suitable means which in the drawings is illustrated as a belt 43. Arranged adjacent the cylinder 41 and adapted to contact with the raised triangular portion 42 is a narrow scoop or scraper 44 that takes off the liquid material, which, by reason of its consistency, adheres to the surface of the triangular portion. The scraper 44 is supported adjacent the cylinder 41 and moves thereacross from side to side. It is so positioned that as it is thus moved, it will make contact with the raised triangular portion 42 of the cylinder and scrape from this raised portion a quantity of material or liquid which will be determined by the position at which the scraper engages the triangular surface. By referring to the drawings it will be seen that when the scraper 44 is at the right hand end of the cylinder 41, it will be in contact with the surface of the triangular raised portion 42 for substantially an entire revolution of the cylinder and since the cylinder, as it revolves in its bath of fit) . adapted for liquid, will be continuously coated with a film of this material, the scraper 44 will remove a streak of this material from the triangular portion during an entire revolution of the cylinder. If the scraper 44 is now moved toward the other end of the cylinder, it will contact with the raised triangular portion 42 for a shorter period of time as the dimension of the triangular surface in the path of the scraper 44 will continually decrease until the scraper is moved to the extremeleft hand position of the feeder 22. In this latter position the contact between the scraper 44 and the triangular portion 42 will be only momentary and, as a result, a minimum of material or liquid will be picked up by the scraper 44 and delivered through its discharge outlet 36.

It has in the past been customary to regulate the position of the scraper 44 in a machine of this type by making hand adjustments of the scraper from time to time, as the volume of the pulp being treated might appear to vary, or on information from the mill man that he intends to vary the flow. Such an arrangement has been found by us to be very unsatisfactory, be-

cause of the human element so introduced. Ths

is particularly true where a large tonnage of material is being treated, as it is almost impossible to estimate the flow or tonnage passing through the mill at any one time. By making the movement of the scraper 44 automatic and controlling its movement mechanically so as to produce a feeding of material'or liquid from the device 22 in proportion to the flow of material through the receptacle 10, it has been found by us to operate very satisfactorily and accomplish results in a more reliable and economical manner.

Connected to the scraper 44, we show the discharge outlet 36 which, in accordance with our present invention, is adapted to convey this material to the material flowing through the outlet 12 to thereby produce a mixture from predetermined proportions of each material. In passing, it should be noted that the material picked up by the scraper 44 and discharged through the outlet 36 is preferably conveyed to a point beyond the receptacle 10 before it is united with the bulk of material passing therethrough.

In Fig. 4 we have shown apparatus which is use in carrying out our invention when it is desired to feed a dry material or substance, as for example to feed zinc dust precipitant in strict proportion to a flowing stream of gold and silver-bearing cyanide solution. In this case the amount of zinc dust fed is also determined by the fiow or tonnage of material passing through the receptacle 10, as will hereinafter appear. The apparatus shown in this figure of the drawings is known as a Merrill zinc dust feeder. It should be understood that this feeder per se forms no part of our invention, but is merely shown to illustrate one type of apparatus whereby our invention can be adapted to the automatic feeding of a dry substance. In this apparatus the dry substance is placed in a hopper 45 which has a discharge outlet 46 from which the substance is conducted to any suitable point. Interposed between the hopper 45 and the discharge outlet 46 is a screw feeding device 47 which is adapted to be driven at different speeds to vary the discharge of material through the outlet 46 in proportion to the flow of the main solution, as will be hereinafter described. A set of stepped pulleys 48 having a belt 49 is provided for transmitting power from a speed varying mechanism 50. The mechanism 50 is driven at a predetermined speed by means of a. belt 51 .and pulley 52. Mounted upon the'shaft of the pulley 52 we provide a cone pulley 53 and cooperating therewith a similar pulley 54 which drives one of the stepped pulleys 48. A belt 55 passes over the cone pulleys 53 and 54. This belt is engaged by a shifting fork 56 mounted upon the rod 21 so that as the beam 14 oscillates,the belt 55 will be shifted by means of the bell crank 17 and the rod 21 to vary the speed of the screw 4'7 and as a result the rate of discharge of material through the outlet 46.

The operation of our invention can best be explained by considering it in conjunction with a practical application thereof. One such application of our device is in the recovery of minerals by the flotation process wherein our device is used to regulate the supply of oil, tar, or other substances which are to be added to a stream of ore pulp on its way to the flotation apparatus. Under these conditions the ore pulp is caused to flow through the receptacle 10 which will, by reason of its suspension, assume a certain predetermined position, depending upon the amount of material therein and as, previously described, this position will determine the amount of oil or other substance to be delivered by means of the liquid feeding device 22. As a result of this arrangement, a predetermined amount of the substance will be continuously supplied to the flotation apparatus, the amount of this substance being in a predetermined proportion to the flow of ore pulp or other material, as previously described.

In applying curinvention to the automatic feeding of zinc dust in metallurgical processes, operation of our apparatus is as follows:-The mineral bearing cyanide solution to be treated is caused to flow through the receptacle 10 and in this case, instead of the rod 21 controlling the operation of the liquid feeding device 22, it will control the position of the belt 55 passing over cone pulleys 53 and 54 and thus vary the speed of the screw 47 interposed between the hopper 45 and the discharge outlet 46 so as to cause a variation in the discharge of zinc dust which will be in direct proportion to the flow of the mineral-bearing solution passing through the receptacle 10. In the use of zinc dust as a 'precipitant of gold and silver from cyanide solution, the principal variable determining variations in amount of zinc needed is the tonnage of solution. The weight of dissolved gold and silver in the solution is also a factor, but this usually does not vary over wide limits during the time of operation and in any case is of much less im portance than variations in the tonnage of solution flowing from hour to hour. It will thus be seen that by automatically adjusting the feed of zinc in the desired proportion to the tonnage of solution, a big improvement in efilciency will result since there will always be sufficient zinc to complete the precipitation 'of whatever amount of solution may be flowing at the time and on the other hand there will never be an overfeed resulting in the waste of zinc and debasing of the precious metal precipitate.

In addition to providing a novel means of mixing materials in predetermined proportions, our invention may also be used to determine the quantity of any material flowing therethrough, whether solid or liquid, so long as it will continually flow by gravity. This assumes, however, that the material being metered will have a substantially constant specific gravity, or in other words,

a constant relation of volume to weight. Such a condition can hardly be said to exist in the case of ore pulps, but the normal variations in density are not usually such as would impair the useful,- ness of our device in determining a record of the tonnage flowing from moment to moment or its average for a 24 hours run. On the other hand, in the metering of solutions when the specific gravity is constant, which is generally the case with solutions, the meter readings obtained by our device will be extremely accurate. In carrying out this feature of our invention we have provided the recording instrument 24 which may be of any standard type. The one herein illustrated contains a time controlled record sheet upon which the stylus 23 is arranged to move in response to movements of the balance beam 14. The record sheet of this instrument can be graduated to register the tons or pounds passing through the balanced receptacle per minute or per hour, and, when properly calibrated with the balance receptacle 10, the graph thus resulting after a predetermined period will form a record of the total quantity that has passed through the receptacle l0 irrespective of how the flow may have fluctuated from hour to hour during that period.

While we have shown the preferred form of our invention as now known to us, it is to be understood that various changes may be made in its construction without departing from the spirit of the invention as defined in the appended claims.

This application is a continuation in part of our application Serial No. 243,170, filed December 28, 1927.

Having thus described our invention, what we claim and desire to secure by Letters Patent 1s 1. In apparatus for effecting a predetermined flow ratio between two materials to be mixed or introduced one into the other, one material being fluid in character and flowing continuously from a source of supply at a flow rate tending to vary between relatively wide limits, a receptacle adapted to receive flow of said one material from said source, said receptacle having a fixed lower discharge orifice whereby varying masses of said one material will be formed within the receptacle above said orifice in accordance with varyin rates of flow into the same, and means responsive to the varying masses of said one material in said receptacle for controlling the rate of supply of the second material to the first named material.

2. In apparatus for eifecting a predetermined flow ratio between two materials to be mixed or introduced one into the other, one material being fluid in character and flowing continuously from a source of supply at a flow rate tending to vary between relatively wide limits, a receptacle adapted to receive flow of said one material from said source, said receptacle having a fixed lower discharge orifice, counterbalancing means connected to said receptacle and serving to support the same for vertical movements, said counterbalancing means being characterized by its application of upward force to said receptacle which increases as the receptacle is lowered, whereby the receptacle assumes various positions of balance for various rates of flow into the same, and means responsive to the positioning of said receptacle for controlling the rate of supply of the second material to said one material.

3. In a method of controlling the feed of one material with respect to the flow of another fluid material whereby the two materials are introduced one into the other according to a predetermined proportioning, characterized by the use of a movable receptacle having a discharge orifice communicating with its lower portion; said method including the steps of causing a continuous but variable flow of the fluid material into said receptacle, whereby different heads of material will be established within said receptacle for different rates of flow, balancing the receptacle at different positions dependent upon the quantity of material within the same, establishing a continuous feed of said one material to the fluid material, and varying said last rate of feed in accordance with the different balanced positions of the receptacle.

EDWARD M. HAMILTON. SELIM E. WOODWORTH.

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