US3866885A

US3866885A - Working method for homogenizing particle material

Info

Publication number: US3866885A
Application number: US300877A
Authority: US
Inventors: Arnold W Gerstel; Karel G L Meyers
Original assignee: Litton Systems Inc
Current assignee: Northrop Grumman Guidance and Electronics Co Inc
Priority date: 1971-10-25
Filing date: 1972-10-25
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18
Also published as: NL7114653A; DE2251457A1; AU4803672A; DE2251457B2; JPS4851359A; ZA727416B; JPS5336180B2; DE2251457C3; IT969894B; FR2157926A1

Abstract

A working method for the homogenizing of particle material including depositing said material from a rotating supply apparatus upon a catch plate or gutter of a circularly moving apparatus layer by layer so as to form a ring-shaped pile and thereafter reclaiming said material from said pile at a fixed position and at a rate approximately equal to the rate at which the material is deposited upon said pile is disclosed.

Description

United States Patent [191 Gerstel et a1.

[4 1 Feb. 18,1975

[ WORKING METHOD FOR HOMOGENIZING PARTICLE MATERIAL [75] Inventors: Arnold W. Gerstel, Woerden; Karel G. L. Meyers, Zaandam, both of Netherlands [73] Assignee: Litton Systems, Inc., Passaic, NJ.

[22] Filed: Oct. 25, 1972 [21] Appl. No.: 300,877

[30] Foreign Application Priority Data Oct. 25, 1971 Netherlands 7114653 [52] US. Cl. 259/3 [51] Int. Cl B0lf 9/10 [58] Field of Search 259/2, 3, 11, 12, 14, 28, 259/29, 30, 72, 81 R, 89

[56] References Cited UNITED STATES PATENTS Berg 2759/2 FOREIGN PATENTS OR APPLICATIONS 1,321,051 2/1963 France 259/2 Primary Examiner-Harvey C. Hornsby Assistant ExaminerPhilip R. Coe Attorney, Agent, or Firm-Morris I. Pollack [57] ABSTRACT A working method for the homogenizing of particle material including depositing said material from a rotating supply apparatus upon a catch plate or gutter of a circularly moving apparatus layer by layer so as to form a ring-shaped pile and thereafter reclaiming said material from said pile at a fixed position and at a rate approximately equal to the rate at which the material is deposited upon said pile is disclosed.

6 Claims, 4 Drawing Figures PATENTED FEB] 8 I975 SHEET 10F 3 fedcbaab edcbaabcdefghi LI PATENTEI] FEB] 8 I975 sum 2 or 5 WORKING METHOD FOR HOMOGENIZING PARTICLE MATERIAL In the first instance the invention relates to a working method to homogenize material consisting of particles in such a way that the material is discharged in layers by a supply apparatus with a circular movement on a catch plate or gutter and it is shaped into a circular pile with a cross-section decreasing from maximum to zero. Hereafter the discharge is continued and at the same moment approximately the same quantity is reclaimed according to the natural slope angle.

Such a working method is known from the Dutch Pat.

No. 127.762. The mentioned pile is lengthened at one end by discharging the material and at the other end by reclaiming the material; between the end and the beginning of the circular pile an open part of the catch plate is always present, moving circularly. According to this Dutch patent it is necessary that the supply apparatus moves back and forth around a vertical shaft. The arch made by the supply apparatus is not exactly a complete circle. The result of the movement of going back and forth is that the supply apparatus has always to be stopped at the turning point of the movement, influencing disadvantageously the capacity and the homogenizing effect.

The invention aims to avoid these disadvantages and to provide a working method mentioned in the beginning, which is quantitatively (greater capacity) and qualitatively (better homogenizing effect) superior to the known method.

The characteristic of the method is that the supply apparatus rotates in one direction with a uniform motion in a closed path, because of the catch plate or gutter also rotating with uniform motion around the same center line as the supply apparatus, however, with a considerably lower revolution velocity, and because of reclaiming the material from the catch plate or gutter at a spatial fixed position. The material to be homogenized often comes from a pile dug by a reclaimer. Apparently the particle material discharged by the reclaimer upon a belt conveyor going to the homogenizing installation often has one or more cyclically returning properties, such as Si percentage, pellet size. When the reclaimer contains a digging wheel provided with buckets having not only an intermittent displacement in length direction of the pile, but also a back and forth movement in transverse direction of the pile, the length of time in which the cyclical properties will return (period time) will be equal to the length of'time during which the digging wheel executes its back and forth movement.

When on the other hand the digging'machine has a drum provided with horizontal rows of buckets stretching over the width of the pile to be dug, the cyclical time will be equal to the time which the drum requires to cover the distance between two subsequent rows of buckets (revolution time divided by number of buckets).

The inhomogeneity of the material is determined by the largest deviations (peaks) with regard to the average in a cyclically returning period. When the turning velocity of the mentioned catch plate or gutter and herewith the quantity of material on that catch plate or gutter during operation is chosen rather arbitrarily, there is a chance that a quantity of material of a peak ized by the catch plate or gutter being rotatable around ofa period will be on the same peak of the next period, so the homogenizing effect will be very small.

The execution of the above-mentioned method, which is preferred, aims to control the homogenization in such a way that from subsequent supplied periods (of the cyclically returning phenomenon) quantities of the corresponding part of the periods are never discharged together on the catch plate or gutter, so that the homogenization always has a maximum effect.

It can be proven that to fulfill these conditions the revolution time of the rotating catch plate or gutter must equal the period time of the cyclically returning properties. The period time that is spoken of here is equal to the product of one or a whole number of times and the minimum period time of the cyclically returning phenomenon.

When the suplied quantity and the reclaimed quantity are in balance, the quantity on the catch plate or gutter will be half as much as the quantity of material in one cyclically returning period of the supply.

The reclaimed material will also show cyclically returning properties, but the maximum deviation with respect to the average will be considerably decreased. The degree depends on the relationship between the number of revolutions per minute of the supply apparatus and the number of revolutions per minute of the catch plate or gutter. This relationship must have a high value preferably at least 50.

In the second instance the invention relates to an apparatus which can execute the described method, which is provided by a supply apparatus rotatable around a vertical shaft and a catch plate or gutter, on which the'particle material can be discharged layer by layer in a ring-shaped pile and a reclaiming apparatus to reclaim the material according to the natural slope angle from the mentioned pile, as is known from the Dutch Pat. No. 127 762. This apparatus is characterthe same center line as the supply apparatus and the reclaiming apparatus of the total apparatus having a fixed position. In order to decrease the kinetic energy of the material falling on the catch plate or gutter as much as possible and still to be able to choose the diameter of the catch plate or gutter relatively large, it is to be preferred that a spreading cone is located between the supply apparatus and the catch plate or gutter. In that case the radius of the supply apparatus can be small with regard to the axis of rotation.

The material discharged near the top of the cone onto the cone slides along the cone surface in the direction of the catch plate or gutter.

The spreading cone can consist of hard steel but in order to prevent unnecessary wear the spreading cone consists preferably of particle material discharged on a plate.

In order to prevent the necessity of stopping the supply in case of malfunctioning of the homogenizing apparatus or because homogenization of the material is not necessary for the time being, the plate which forms I the spreading cone can have an opening which can be FIG. 2 shows an unfolded ring-shaped pile built up out of layers formed by the homogenisator on two t seconds apart.

FIG. 3 gives a side view of the homogenizing apparatus.

FIG. 4 gives a top view.

The schematic FIG. 1 shows a pile 1 consisting of inhomogenous material. This pile gives a perspective view of the top. The pile is dug off by a rotating digging wheel 2 provided with buckets, moving from side to side and which at each turn moves forward over a length corresponding with the desired depth of the cut. Rotating digging wheel 2 is of conventional type as shown in US. Pat. No. 3,069,027. Its operation and the path of removal and movement of the material operated in are clearly shown and described in said patent.

The reclaimed material is discharged by the wheel 2 upon a conveyor 3 axially stretching through it and is subsequently transported via a number of conveyors 4, 5 and 6 to a homogenizing apparatus. This homogenizing apparatus has a relatively fast rotating supply apparatus 8, a spreading cone shaped on a plate 9, a relatively slowly rotating catch gutter l 1 and a material extractor 12 rotating around a fixed shaft put into a slit of the catch gutter as previously mentioned on page 4 (beginning at line 16) the spreading cone may either be a cone shaped mechanical element formed of hard material such as steel, or it may be formed from the particle material discharged onto plate 9 as shown in FIG. 1. This extractor deposits the homogenized material on a conveyor 13. For constructive reasons it is preferable that plate 9 rotates with the catch gutter 11. The supply apparatus 8 rotates at a constant speed. It discharges at a radius, from its axis of rotation, which is small in comparison to the radius of plate 9 so that the material ends up near the top of the cone 10.

The centrifugal acceleration forces which are generated in the supply apparatus 8 will then also be small. The material slides along the slowly rotating cone 10 on the plate 11 and ends up with little kinetic energy.

Layers are shaped of which the number depends on the relationship of the number of revolutions of the supply 8 with respect to the number of revolutions of plate 11. In the homogenizing apparatus there is no reversal of motion so that very good homogenizing results are obtained and the same high capacity is possible. The material supplied to the homogenisator often has periodical characteristics. When for instance the pile l is divided into strips a thru j, these strips can be found as indicated on the conveyors 4, 5 and 6. The minimum period of the periodical characteristics (Si0 percentage, pellet size, etc.) will in this case have a length A. The supply 8 rotating very fast with respect to the catch plate 11, the strips a thru j will be divided over many layers, which can be seen in FIG. 1. In this figure, showing an unfolded view of the shaped pile of material on plate 11 on two I sec. apart, P is the fixed material extractor point. The outflow direction is indicated by an arrow. The direction approximates the natural slope angle.

When the number of revolutions of catch plate 11 is not optimal with respect to the time (duration) wherein a period A is dug off, it could happen that from two subsequent strips A parts of similar strips will end up one above the other (e.g., a part of strip b of a period A upon a part of strip 12 of a next period A). This means that after all a peak in a certain phenomenon can arise.

Therefore it is required that the time in which catch plate ll makes one revolution be chosen in such a way with respect to the time in which a period (batch) A (FIG. 1) is dug off from pile 1 that such a piling up of similar parts from subsequent periods is avoided.

' It is therefore necessary that on plate 11 during homogenization a quantity is always present which corresponds with half the quantity of a whole period A, or a whole number times period A.

The revolution time of plate 11 must therefore be equal to the period time of the cyclically returning properties, whereby the period time is the product of one or a whole number of times and the minimum time of the cyclically returning phenomenon.

In that case the properties that were periodical on the conveyors 3 thru 6 are also cyclical in the outlet, but the maximum deviation with respect to the average will be considerably decreased with respect to the maximum deviation on the conveyors 3 thru 6. It will be clear that the homogenization is aided by a large number of layers on plate 1 1, that is to say by a high number of revolutions of supply 8. The relationship between the number of revolutions of supply 8 with respect to the number of revolutions of plate 11 is preferably at least 50.

A possible ordering of material from the strips a thru j is shown in FIG. 2. It is clearly shown that no addition of deviations with respect to the average has taken place. The homogenization effect is-always at its maximum;

The homogenization of materials when the abovementioned cyclically returning properties are taken into account can be indicated by the term batch blending. (A batch is the quantity in one period A.)

FIGS. 3 and 4 show some constructive details of the homogenizing apparatus according to the invention. The catch plate 11 is by supports l4 connected with plate 9.

The whole of plate 11, supports 14 and plate 9 are borne on a component 16 and are driven by a motor and transmission not illustrated. On plate 11 a ringshaped gutter is bounded by two concentrical

upright walls

17, 18 mounted on theaxis of revolution.

In plate 9 and opening has been made which is normally closed by a slide plate 20, and which discharges into a channel 21. It is possible to by-pass the homogenisator in case of continuous supply by proper movement of slide plate 20 so that material 10 passes directly into channel 21 and onto conveyor 13 to thus bring about a short-circuit connection between the supply apparatus and the outlet. The rotatable supply apparatus 8 is borne at 21 and is driven by a motor and transmission not illustrated.

Material that is discharged from conveyor 6 ends up on the ring shaped gutter 25 and moves into apparatus 8 which has a side opening. The same motor is best used for plate 11 and supply 8. It is desirable in order to be able to adjust the relationship between the number of revolutions on plate 11 and apparatus 8, that the transmission ratio is adjustable.

The extractor of the material 12 consists of a rotating plow feeder. Plow Feeder 12 rotates about the axis of rotation shown in FIG. 3 to remove material 12 in a conventional manner, pushing same into the chute shown onto conveyor 13. The propelling motor is not illustrated.

In summary it can be stated that it is essential for the described method and the installation that the supply apparatus 8 rotates at a high number of revolutions, the catch plate 11 with a low number of revolutions and that the extraction of material takes place at a fixed point. When these conditions are met a very high capacity is possible and the homogenizing effect is good, particularly when care is taken that in case of a cyclically returning phenomenon on plate 11 always half of the quantity of one period (1A, 2A, 3A, etc.) is present.

Within the framework of the invention various modifications of the described installation are of course possible. For example the spreading cone shaped by particle material can consist of steelplate. Furthermore this cone can be stationary, but for constructive reasons it is better that it is connected with the rotating plate 11.

We claim:

1. A working method for the homogenizing of particle material: comprsing a. rotating a particle supply apparatus at a predetermined speed in a closed circuit and with a uniform motion about a predetermined axis of rotation;

b. providing particle material to and from said supply apparatus;

c depositing said particle material layer by layer upon a catch plate or gutter of a circularly moving apparatus so as to form a ring-shaped pile having a first end rising up from said circularly moving apparatus at the natural slope angle formed by said particle material as it is deposited and a second end which rises up to a predetermined maximum height from said circularly moving apparatus;

d. moving said circularly moving apparatus about said predetermined axis of rotation at a speed considerably lower in velocity than said predetermined speed of said supply apparatus; and

e. reclaiming said particle material from said pile at a fixed position and at a rate approximately equal to the rate at which said particle material is deposited upon said pile.

2. Working method according to claim 1 whereby the material to be homogenized which is transported to the rotating supply apparatus, has one or more cyclically returning characteristics (e.g. SiO percentage, pellet size) which return on a uniform period, with the characteristic that the rotation time of the rotating catch plate or gutter is chosen equal to the periodical time of the cyclically returning characteristics.

3. Working method according to claim 2 with the characteristic that the ratio of the number of revolutions per minute of the supply apparatus to the number of revolutions per minute of the catch plate or gutter is at least 50.

4. The working method of claim 1 including provid ing a spreading cone between said supply apparatus and said catch plate or gutter.

5. The working method of claim 4 including depositing said particle material upon a spreading cone plate to form said spreading cone.

6. The working method of claim 5 including providing an opening in said spreading cone plate and a closure for said opening such that when said closure is opened a short-circuit is provided between said supply apparatus and an outlet for the particle material.

Claims

1. A working method for the homogenizing of particle material: comprsing a. rotating a particle supply apparatus at a predetermined speed in a closed circuit and with a uniform motion about a predetermined axis of rotation; b. providing particle material to and from said supply apparatus; c. depositing said particle material layer by layer upon a catch plate or gutter of a circularly moving apparatus so as to form a ring-shaped pile having a first end rising up from said circularly moving apparatus at the natural slope angle formed by said particle material as it is deposited and a second end which rises up to a predetermined maximum height from said circularly moving apparatus; d. moving said circularLy moving apparatus about said predetermined axis of rotation at a speed considerably lower in velocity than said predetermined speed of said supply apparatus; and e. reclaiming said particle material from said pile at a fixed position and at a rate approximately equal to the rate at which said particle material is deposited upon said pile.

2. Working method according to claim 1 whereby the material to be homogenized which is transported to the rotating supply apparatus, has one or more cyclically returning characteristics (e.g. SiO2 percentage, pellet size) which return on a uniform period, with the characteristic that the rotation time of the rotating catch plate or gutter is chosen equal to the periodical time of the cyclically returning characteristics.

4. The working method of claim 1 including providing a spreading cone between said supply apparatus and said catch plate or gutter.