US2674396A - Deaerating device for pulverulent material - Google Patents

Description

W. R. PETERSON DEAERATING DEVICE FOR PULVERULENT MATERIAL Filed Eeo. 1'7, 1949 2 Sheets-Sheet l INVENTOR.

W1 LLIA M R .PETERSON.

BY y AIM,

"L IYKDL ATTORNEYS.

AP g E954 W. R. PETERSON 2674,39

DEAERATING DEVICE FOR FULVERULENT MATERIAL Filed Dec. 17, 1949 2 Sheets-Sheet 2 HIGH LEVEL Lew Laval.

' INVENTOR. \flg uAn l RPETERS N.

ATTORNEJQ Patented Apr. 6, 1954 DEAERATING DEVICE FOR PULVERULENT MATERIAL William R. Peterson, Oswego, N. Y., assignor to St. Regis Paper Company, New York, N. Y., a

corporation of New York Application December 17, 1949, Serial No. 133,559

4 Claims.

This invention relates to deaerating devices, and more particularly to such devices for deaerating light, finely ground or ulverulent materials such as those of a fiuffy nature whereby such material can be packed into containers such as paper valve bags with greater efficiency than heretofore possible.

In the packing of very light fiuffy materials of an aerated pulverulent nature such as sodium silicate, magnesium silicate, diatomaceous earth, and kaolin clay, a serious problem has arisen in the past because it has not been possible to make most eifioient use of the space within a given container because of the aerated nature of such substance. If said substances could be deaerated prior to packing into the container such as a multi-wall valve bag, substantially larger percentages of material could be inserted into the container, for example, up to -20%, which may result in a saving of the paper or the material of the container to a very worthwhile and significant degree.

Furthermore, after material such as that above described has been packed into flexible containers of the multi-wall bag variety, the bags are quite difiicult to stack properly because of the soft and flufiy nature of the material which limits the number of bags which can be superimposed upon one another. However, if proper deaeration is effected of the material, the bags containing same can be stacked with greater facility.

Such deaeration of the material preferably should take place just before the packing thereof into containers. Such :deaeration should occur preferably in such a manner that the material will not have to be moved or agitated appreciably after deaeration in order to avoid reintroduction of air therein, for example, as by conveying material over a substantial distance on conveyor belts which may involve the dumping or falling of the material over substantial distances.

Attempts have been made in the past to deaerate such material prior to packing same into containers. However, they have been unsuccessful because the prior devices therefor have required unusually frequent cleaning, and have been subject to frequent clogging and consequent arresting of the proper operation thereof.

One of the objects of the present invention is to overcome the above difficulties or to reduce same to insignificance.

The invention in one aspect thereof comprises a deaerating device for use with a valve bag packing unit and comprises a receptacle into which such aerated pulverulen material is fed to a preselected level by a suitable supply means which are responsive to the level thereof in the receptacle, such supply means being arrested when the desired level is reached. The material is gently agitated within the receptacle, for example, by means of a rotatable agitator which breaks the surface of the material. Suction is applied to the receptacle through an orifice which is located therein above said preselected level of material. The agitator is moved or rotated slowly stirring the material and disturbing it to an extent that the air held therein is moved upward toward the region above the material level within the container subject to suction. Thereby such air is removed from the material and the receptacle, reducing the volume and increasing the density of the material.

Various further and more specific objects, features and advantages of the invention will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate, by way of example, preferred arrangements of apparatus for carrying out the invention. The invention consists in such novel methods and combinations of features and method steps as may be shown and described in connection with the equipment herein disclosed.

In the drawings:

Fig. 1 is a side elevation partly in section and with parts broken away of one form of apparatus embodying the present invention; and

Fig. 2 is a side elevation also partly in section and with parts broken away of another form of apparatus embodying the present invention.

Referring to the drawings in further detail, the novel deaerating device is employed with a valve bag packer unit as at In which is provided with a well known type of filling tube as at I I through which there extends a filling screw I2 which is positioned partially within the tube H and partially within a bin l3 within the packer unit it. The bin I3 has rotatably mounted therein a suitable agitator as at M for insuring adequate distribution of material over that portion of the filling screw 12 which is within said bin.

The filling screw 12 is continuously driven during the filling of each bag by any suitable means and at a substantially high velocity as compared to that of the agitator or spreader M which may be continuously driven.

The deaerating device proper is indicated as at l5 and is constituted by a receptacle I5 adapted for receiving pulverulent material of the nature above described as at IT. The receptacle I6 is provided with a suitable discharge orifice I6a through which material may be delivered to the bin I3 of the packing unit I0. Also said receptacle is provided with a suitable inlet orifice as at IBb which is in communication with a suitable feeder device as at l8 for supplying material to the receptacle. In the form shown the mechanism for feeding material to the receptacle is constituted by a suitable screw as at I8a which is driven by any suitable means such as motor I9. The feeder device I8 moves material preferably from a main bin (not shown) into the receptacle I6 via a suitable feeding tube 20 which interconnects a trough 2I, in which the screw I8a rotates, with the inlet orifice IBb. The motor I9, which controls the feeder IBa, is controlled to maintain a preselected level or volume of material in the receptacle Hi. In the form shown, a device is provided which arrests the motor I9 when the level of material therein comes up to a preselected point indicated approximately as at Ila. Any suitable means of this character may be employed, for example, a switch I9a, responsive to movement of a diaphragm ISD, is actuatable by the pressure of material when it reaches such level Ila. By such switch and other electrically interconnected means the motor I9 is arrested. Motor I9 is started when such level falls below I la.

The material I! within the receptacle I6 is subjected to the combined action of gentle agitation and suction by virtue of a rotatable agitator indicated as at 22 and a suction device as at 23, the latter being in communication with the receptacle l6 via an orifice I60 which is located above the level Ila. Thus there is a spaced relationship between said level Ila and the orifice I60. In order to prevent unequal air pressures on opposite sides of diaphragm Ii-ib, an outer surrounding chamber I90 therefor may be connected by a tube 23a into the suction line as at 231).

The suction means is for the purpose of placing the region above the material in the receptacle under at least a partial vacuum in order to facilitate the removal of air which works its way to the surface of the material as a result of the agitation thereof. Of course, a certain amount of dust is also removed by the suction device. The extent of the vacuum can advantageously be between about one to three inches of mercury. The main bin (not shown), from which material is forced via tube 20, can be sealed in a suitable manner to assist in maintaining the vacuum in the receptacle IS.

The above-mentioned agitator 22 in the form shown is constituted by a vertically positioned shaft 22a which is mounted for rotation in spaced journal bearings as at 2% and 220 which are positioned at the upper extremity thereof whereby the central rod 22a extends downwardly into the receptacle and is not supported at its lower extremity as viewed in the drawing. This eliminates the necessity for oily bearings at the lower extremity which might foul the pulverulent material. Secured to the rotatable central support rod 22a are a plurality of outwardly or radially extending arms as at 22d. Suitable power means for rotating the agitator 22 are provided as at 24 comprising an electric motor which is operatively connected with the agitator preferably through the intermediary of a reduction gear 25. It is desirable gently to agitate the material. In general the degree of agitation is a function of the degree of aeration of the matcrial and a function of other factors to be explained more fully below. The agitator 22, of course, can take a number of different forms, for example, it can be in the form of a helix or, for example, a so-called "lawn mower type of agitator having a plurality of blades held in spaced relationship to the central rod 22a upon radially extending arms. Such blades can, of course, be parallel to the central rod 22a or they can be helical in conformation.

In operation, the agitator 22 disturbs or agitates the particles of pulverulent aerated material in such a manner that air, which for example may be collected in bubbles in the material, can move upwardly to the lower pressure region, namely, the region above the level of the material in the receptacle whereby such air is removed by the suction device 23. The partial suction above the material in the receptacle very strongly assists in deaerating same by facilitating upward movement of the air under the influence of the agitator. Valve bags are filled through spout I I and replacement material is automatically fed into receptacle I6 by means of screw I8, motor l9 and switch I9a.

The discharge orifice l6a of the receptacle Hi can be directly in communication with the packer bin I3, as shown in Fig. 1, whereby material is directly discharged into such bin. It is desirable to have the receptacle I6 and the bin I3 of sufficiently large volume to insure that an adequate period of deaeration will take place for each bag full of material prior to filling into a oag. That is, the deaerator I5 should be capable of deaerating material adequately at a rate equal to the bag filling rate of the packer ii).

A second embodiment of the invention is shown in Fig. 2 and is constituted in general by a receptacle or deaeration bin 26 of substantial volume which preferably is constituted by a large hollow vertical cylindrical portion 26a and a lower portion 26b in the shape of a funnel which directs material to a container packing unit generally shown at 21. The latter unit, in the form shown, is of a so-called simultaneous filling and weighing type for valve bags having a multivane impeller as at 28 which rotates, for example, at about 800 R. P. M. on a vertical axis in such a manner that material is urged by centrifugal iii) force through a filling tube orifice as at 29 to which a suitable tube (not shown) may be secured which is adapted for insertion into a valve of a valve bag.

The funnel portion 26b of the deaeration bin at the lower outlet orifice thereof at 260 is directly in communication with and in register with a tubular portion 30 which directs material onto the impeller 28. It has been found desirable for the diameter of the orifice 2Ec, the tubular portion 30 and the impeller 28 to be substantially equal.

The deaeration bin 26 is provided with an airtight cover as at 26d. having a centrally located orifice 26c through which material is fed into such bin via a throat tube 3I having an inlet orifice at 3").

Finely ground aerated material of a fiuffed nature, such as diatomaceous earth, is fed into throat tube 3I by means of a feeder element indicated generally at 32 which is constituted by an auger type screw 33 which rotates within a feeder tube 34 to urge material into said throat tube 3| at the top thereof as shown in Fig. 2. A suitable inlet joint as at 35 guides material from the filler tube 34 into throat tube 3|.

The auger 33 of the feeder element 32, in the form shown, is inclined at an angle of approximately 50 with the output extremity thereof being higher than the input extremity. A main supply bin as at 36 is in communication with an input mouth 32a of the feeder element 32 whereby the aerated material is continuously fed to such feeder unit and will be conveyed up to the throat tube 3| when the auger 33 is in motion. The inclination of tube 34 and the upward path of material assists in maintaining the bin 26 in a substantially airtight condition because material held in said tube forms or tends to form an air seal. The screw 33 may be of progressively diminishing pitch, if desired, in order to assist in deaerating the material and to aid in the formation of such an air seal by at least partially compressing same.

The auger 33 is operatively associated with a suitable power source such as an electric motor 31, the latter being under the influence of a device which is responsive to the level of material in the deaeration bin 26 as will appear more fully hereinafter.

It has been found desirable to rotate auger 33 at approximately 700 R. P. M. when packing a material such as sodium silicate.

Deaeration of the material in the bin 26 is accomplished in a manner partially similar to that described in connection with Fig. 1, namely, by the application of suction and by agitation. However, in the embodiment of Fig. 2, means are provided for continuously breaking and agitating the upper surface of the material throughout a large proportion of or substantially the entire area thereof. This has been found materially to assist deaeration. Also in the modification shown in Fig. 2, the deaeration bin 26 is of such large preselected volume in comparison to the rate at which material is with-- drawn therefrom by the packer unit 21 that a given volumetric increment of material which is deposited in the bin may remain therein and undergo deaeration for a substantial period before discharge. The length of the deaeration period depends upon the type of material, the degree of its aeration, and other factors. Bin 26, for example, may be forty-eight inches in diameter and fifty-six inches in height.

In order to provide the desired vacuum in the region within the deaeration bin above the level of material, a suitable suction line as at 38 is provided which is connected to a pump (not shown) capable of moving, for example, 500 to 1,000 cubic feet of air per minute. The suction line 38 is connected to the bin 26 via the throat tube 3| and is in communication with the latter at an orifice 3| a. A vacuum of the order of one to three inches of mercury thus may be maintained in bin 26 above the material.

The agitator element which rotates within the deaeration bin 26 is indicated at 39 and comprises a central supporting shaft 40 which is mounted in suitable journals adjacent the upper and lower extremities thereof as at Al and 42. Shaft 40 is, in the form shown, vertical and a portion of the weight thereof preferably is supported by means of the journal 42 through the intermediary of a flange 43. A supporting ele-' ment in the nature of a spider as at M supports the journal 42 and consists of a number of rods or arms which interconnect said journal with the sides of the bin 26. The elements which move angularly through the material in the bin 26 to accelerate the deaeration thereof in the throughout substantially its entire area, is continuously broken and agitated thereby assisting in the movement of air held by the material upwardly into the low pressure region.

The agitator element 39 is continuously driven by means of a motor 39a through the interme diary of a suitable reduction gear 33?), there being conventional means for inter-connecting said motor, reduction gear, and agitator. The reduction gear 3% reduces the speed of the motor 3% to drive the agitator at a speed of the order of to R. P. M.

Such vertically extending rods in the modification of Fig. 2 are divided into two groups:

(it) Those rods as at $5 which extend vertically from substantially the level of the journal 42 up to the inlet orifice 3! I). These rods may be rigidly secured to the central supporting shaft it as by horizontally extending arms 46. It will be noted that the rods 45 extend up into the throat tube 3i and by virtue of their rotation prevent the clogging of this tube anl also assist in some measure in the deaeration of the material passing therethrough. The rods 45 are preferably held each at ,a differing radial distance from the axis of the supporting shaft 40.

(12) Those rods as at M which extend substantially from the level of the journal d2 up to a point substantially above the highest expected level of material in the bin 26. These rods also are rigidly secured to the central supporting shaft it) as by horizontal arms t3, the radial distances of the vertical rods 4'! varying as desired in order to accomplish a thorough agitation of the entire volume and surface area of material in the bin 26.

In the form shown there are four rods 45 each at a different distance from the axis of rotation. and also four rods 4'! each of which also is at a different distance from said axis.

A third group of agitating rods preferably are provided for the funnel shaped portion 25b of the bin 20, portions of which rods may extend downwardly into the tubular portion 30 and to Within a short distance, for example, one inch, from the rotatable impeller 20. Such agitator rods are shown at 39, 50, 5!, 52 and 53. The latter are secured to the shaft M: by means of a horizontal arm 54 to which said rods are secured as by welding. Said rods 55 and d? also may be rigidly secured to their respective arms by welding. Rods 39-53, inclusive, may be positioned directly beneath their respective rods l-l', as shown in Fig. -2, if desired.

Beds 4943, of course, are formed of such lengths to conform to the funnel shaped portion 2% of the bin 2t and the lower extremities of rods G9, 50, 52 and 53 extend into close proximity to the inner surface of such funnel portion in order to prevent the clinging of material thereto. Rod 55 mounted directly over the outlet orifice 25c and hence does not move above an inner inclined surface of such funnel portion. In order to insure that there is no clogging of material at the outlet 250, it is desirable to ailix a crank shaped portion a to the extremity of the rod impeller 28. 50a, as at fific moves in proximity with :but in .511 'as at 501), the lower extremity-of suchtcrank shaped portion Eta extending down into :close proximity with but inspaced relationshipto :the Apart of thecrank shaped portion spaced relation to'themargin of the orifice'26c which'assists materially'in preventing the clogging of such orifice. A vertical extension 5111 is secured to the'vertical rod as at 5") and extends down to the same lower levelaas crank portion 50a.

The-function of the agitator rods .49-53, inclusive, and 50a, 5la'thus1not only is the agitation of the material to facilitatedeaeration but also includes the prevention of the clogging of the material in the funnel 231) and tube 30.

The level of the material in the bin 26, of course, depends upon the activity of the feeder element 32 and hence, in the form shown, upon the energization of the motor 31 which rotates the auger 33. In this modification also, as in the modification of Fig. l, the motor'3'l is under the influence of a level responsive device as at 55 which is designed for maintaining the level of material in the bin between two limits, namely, a high level as =at-56 and a low level as at 51. The level responsive device is operatively associated with the -motor 31 by any suitable means whereby said motor is energized to actuate the feeder element 32 to feed material to the bin when the level-reaches that indicated at 51, and to arrest said feeder element when the level of material in the bin reaches that indicated at 56.

Such level responsive device 55 may include top and bottom switches as at 55a, 55b respectively for the high and low levels 56 and 51. Each switch is associated with a diaphragm in a manner analogous to that shown in Fig. 1 regarding switch 19a. Top switch 55a is movable to an open position in response to the pressure of material within the bin against its diaphragm. The bottom switch 551) may be provided with a counterweight to insure positive action and to close same when material in thebin falls below its diaphragm. When the bottom switch isclosed the motor 37 is operated to supply material to bin 26 until the circuit thereof is broken by the opening of switch 55a in response to material pressing against-the latters diaphragm.

In order to equalize air pressures on opposite sides of such diaphragms the exterior surfaces of the latter are subjected to at'best a-partial vacuum via conduit 550 which communicates with conduit The interior surfaces of the diaphragm are, of course, subjectto a similar partial vacuum.

The suction orifice 31a is positioned substantially above the highest expected level of material (56) whereby there is a region above such level which is always subjected to a vacuum when the machine is in operation.

The novel apparatus herein described not only removes a substantial amount ofair held by the material, thereby deaerating same to a preselected degree, but bag filling time is reduced substantially for a given weight of such light fluffed material, as compared to past requirements. Thus because of the increased density of the material after deaeration by the above-described apparatus, it is possible for the impeller as at 28 (Fig. 2) to impel a larger weight of material per unit time into a valve bag.

In operation, a large supply of material is maintained in the deaeration bin 26 by the feeder element 32 under the influence of the level responsive device :55.

The agitator 39 is continuously driven and the upper surfaceof the material in the bin26 throughout substantially its entire area is continuously-broken and agitated by means of the rods 45 and 41 which at all times extend through such surface. Moreover, the .volume of material below such surface is relatively gently agitated by means of those portions of said rods 45 and 41 which extend beneath the upper levelof material, and also by means of the rods 49-53, inclusive, including the extensions 50a and 51a. The impeller 28 may be continuously driven whereby deaerated material isurged outwardly toward the filling tube orifice -29,-there being suitable valvemeans (not shown) forcut- .material and the withdrawal'rate is selected to cause a given volumetric increment of material in the bin to undergo-deaeration as above described for periods, for example, up to aboutiten minutes between the timeit is deposited in such bin and the time it is fed through the orifice .29. The feeder element 32, after filling the bin up to the level 56, will be arrested and material will be withdrawn from the bin-through the orifice 29 until the level has lowered to that indicated'at 7 51 whereupon the motor 31 :vvillbe reenergized to introduce additionalmaterial into the bin up to the level 56.

If desired, the size of the .bin .26 and its.-conformation may be such that a given volumetric increment of material will .be subjected vto.deaeration for .a period greater or less :than the above-mentioned ten minutes. In general, it has been found that the .longer the period of deaeration under the influence of (a) suction, (1)) internal. agitation of the material, and (c) agitation'of substantially the entire surface area of the material, .the .greater will be the extent of .deaeration and volumetric reduction .of the material. However, .the period of deaeration is selected .in response to a number of factors among which are: state .of settling .of .the material; degree of aeration; type of material;

weight, .etc.

The agitation of ,thematerial in the bin .26 by means of said rods causes the air held by the material to move upwardly toward theregionof ,material and thence out of the bin under the influence of suction.

While the invention has been described with respect to certain preferred examples which have given satisfactory results, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications maybe made without departing from the spirit andscope of theinvention, and it'isintended, therefore, in the appended claims to cover all such changes and modifications.

What is claimed is: 1. In apparatus of the class described, the

combination comprising: a valve bag packing unit including a packer bin for the receipt of material to be packed thereby, a valve bag filling tube and an impeller for urging material from said packer bin through said tube; a deaeration bin comprising a hollow vertical tubular receptacle enclosed except for a discharge orifice in communication with said packer bin and an inlet orifice for pulverulent aerated material, said packer bin being beneath said deaeration bin; supply means for supplying such pulverulent aerated material to such deaeration bin through said inlet orifice; mechanism responsive to the level of the top surface of material in said deaeration bin and operatively connected to said supply means for controlling the latter for maintaining said deaeration bin filled to a preselected level within predetermined limits; agitator means positioned for agitating and breaking substantially the entire top surface area of material in said deaeration bin at such preselected level within such predetermined limits; agitator means for concurrently agitating the material in said deaeration bin throughout substantially the entire volume thereof beneath such level; and means for maintaining a suction within said deaeration bin above such level.

2. In apparatus of the class described for use with a Valve bag packing unit having a packer bin for the receipt of material to be packed thereby; a deaeration bin comprising a hollow vertical tubular receptacle enclosed except for a discharge orifice in communication with the packer bin and an inlet orifice for pulverulent aerated material, the packer bin being directly beneath said deaeration bin; supply means for supplying a stream of such pulverulent aerated material to such bins via said inlet orifice; mechanism responsive to the depth of the material in said deaeration bin and operatively connected to said supply means for actuating the latter for maintaining said deaeration bin filled to a preselected depth, the top surface of such material being at a preselected level at such depth; agitator means including a plurality of fingers positioned for agitating and breaking substantially the entire top surface area. of material in said deaeration bin at such preselected level; agitator means for concurrently agitating the material in said deaeration bin throughout substantially the entire volume thereof beneath such level; and means for maintaining a suction within said deaeration bin above such level.

3. In apparatus of the class described, the combination comprising: a valve bag packing unit including a packer bin for the receipt of material to be packed thereby, a valve bag filling tube and an impeller for urging material from said packer bin through said tube; a deaeration bin comprising a vertical tubular receptacle enclosed except for a discharge orifice in communication with said packer bin and an inlet orifice for pulverulent aerated material; supply means for supplying a stream of such pulverulent aerated material to such deaeration bin through said inlet orifice; control mechanism for said supply means responsive to the position of the top surface of material in said deaeration bin and operatively connected to said supply means for maintaining said deaeration bin filled to a preselected level within predetermined limits; agitator means having a plurality of members positioned for agitating and breaking substantially the entire top surface area of material in said deaeration bin at such preselected level within such predetermined limits; agitator means for concurrently agitating the material in said deaeration bin throughout substantially the entire volume thereof beneath such level; and means for maintaining a suction within said deaeration bin above such level.

4. In apparatus of the class described, the combination comprising: a valve bag packing unit including a packer bin for the receipt of material to be packed thereby; a valve bag filling tube and an impeller for urging material from said packer bin through said tube; a deaeration bin comprising a hollow vertical tubular receptacle enclosed except for a discharge orifice in communication with said packer bin and an inlet orifice for pulverulent aerated material; supply means for supplying a stream of such pulverulent aerated material to such deaeration bin through said inlet orifice, such supply means including an inclined feeder tube having an auger type screw therein, said tube having an outlet at the high extremity thereof at said bin inlet orifice and having an inlet at the low extremity thereof; mechanism responsive to the position of the top surface of material in said deaeration bin and operatively connected to said supply means for filling said deaeration bin to a preselected level; agitator means positioned for agitating substantially the entire area of the top surface of material in said deaeration bin at such preselected level; agitator means for agitating the material in said deaeration bin substantially throughout the entire volume thereof beneath such level; and means for maintaining a suction within said deaeration bin above such level.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,121,633 Hartman et a1 June 21, 1938 2,448,745 Struckmann Sept. 7, 1948 2,485,857 Bower Oct. 25, 1949 2,509,985 Morrow May 30, 1950 2,548,075 Stoker Apr. 10, 1951 FOREIGN PATENTS Number Country Date 618,502 Germany Sept. 10, 1935

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