US3164649A - Method of forming high density masses of pulverulent material - Google Patents

Description

1965 R. F. POOLE ETAL 3,164,649

METHOD OF FORMING HIGH DENSITY MASSES OF PULVERULENT MATERIAL Filed March 28, 1962 3 Sheets-Sheet 1 .zzfizz'nzmrs ROBERT F. POOLE a" conuss c. WARD 1965 R. F. POOLE ETAL 3,164,649

METHOD OF FORMING HIGH DENSITY MASSES 0F PULVERULENT MATERIAL Filed March 28, 1962 5 Sheets-Sheet 2 Jan. 5, 1965 R. F. POOLE ETAL 3,164,649

METHOD OF FORMING HIGH DENSITY MASSES 0F PULVERULENT MATERIAL Filed March 28, 1962 3 Sheets-Sheet s 4,1 42 31 loo/Roo Lu All ll 1/ 1 M 39 2: 7: z's 29 United States-Patent 3,164,649 METHOD FGRMING HIGH DENSITY MASSES 0F YIJIJVERULENT MATERIAL Robert F. Poole, Palos Park, and Corliss C. Ward, Chicago, Ill., assignors to Chisholm, Boyd & White Company, a corporation of Illinois Filed Mar. 28, 1962, Ser. No. 183,238 4- Ciaims. (Cl. 264-121) This invention relates to the making of objects formed of ceramic or refractory material, and in particular, relates to a method of preforming the objects for subsequent high density, dry-press type compaction thereof.

In forming blocks or the like of ceramic or refractory material, the material is pressed in a press cavity, commonly referred to as a matrix, and is compacted therein to form a high density mass. heretofore utilized for such compaction, relatively deep matrix cavities have been required in order to accom-- modate the relatively low bulk density material. Further, in the conventional presses the'material has tended to bridge, thereby forming pockets resulting in a non-homogeneous preform. Still further, where pressurized air has not been utilized to deliver the material to the matrix cavity, it has heretofore been necessary to sufliciently delay the mechanical compacting action to allow the entrapped air !in the material to be exhausted from the cavity during pressing of the material therein. This timeconsuming, and, therefore, costly, step obviously is highly disadvantageous in this art. V

The present invention comprehends an improved method of forming the compacting preforms eliminating the above-discussed disadvantages. Thus, a principal feature of the present invention is the provision of a new and improved method of forming a high particle density mass of ceramic or refractory material.

Another feature of the invention is the provision of such a method permitting concurrent forming of a plurality of such masses in a novel and simple manner.

\ A further feature of the invention is the provision of such a method wherein thematerial is delivered to the matrix cavity by entrainment in high pressure air streams while substantially uniform distribution of the material is effected in the air streams by an improved mechanical agitation of the material delivered thereto. i

A yet further feature of the invention is the provision of such a method wherein the air is substantially exhausted from the matrix cavity directly upon removal of the entrained material'from the airstream introduced therein.

A still further feature of the invention is the provision of such a method wherein the velocity of the air streams carrying the material into the matrix cavity is utilized to effect a partial compaction of the material introduced therein, thereby effectively minimizing the required size of the cavity, and producing a more intimate internal structure of the :final compacted mass which increases both:

In the conventional presses,

"ice

' closed in the drawings, a pneumatic power press generally designated is shown to comprise a twin cavity press including a pair of upper cross-head cylinders 11, a pair of upper pneumatic hammers 12, a pair of upper plungers 13, 'a'pair of matrices =14, a pair of lower plungers 15, a pair of lower cross-head cylinders =16, a pair of hammers 17, respectively.

FIGURE 1 is afront elevationof a pneumatic power means; and

FIGURE 5 is a rear end elevation of the loading chamber means.

In the exemplary embodiment of the invention, as dis- The present invention is concerned with the delivery of the ceramic or refractory material to the cavities for such subsequent compaction. More specifically, the press 10 is provided with a horizontally extending track 20 which,

' as best seen in FIGURES 2 and 3, extends along opposite sides of the matrices 14 to permit a 'cart 21, defining a pair of loading chambers 22, to be selectively disposed over the cavities 19, or laterally thereof. The refractory material is delivered to the loading chambers 22 within the cart from a suitable storage means (not shown)- through a suitable chute .23 when the cart is in the right hand or loading position, as shown in FIGURE 2. The loaded cart is then moved into overlying relationship with the cavities 19, and the material is delivered from the cart into the cavities, as will be brought out in greater detail hereinafter.

More specifically, cart 21 includes a bottom Wall 24 through which extends a plurality of blow tubes 25. The blow tubes extend downwardly tluough an exhaust space 26 below the wall 24, the lower boundary of the space 26 being defined by a perforate chamber vent plate 27 carrying a foraminous steel sheet 28. The plate 27 and superposed screen 28 are spaced below the wall 24 by suitable spacers 29, and the blow tubes 25 extend downwardly through the space 26, the screen 28 and the plate 27 to open downwardly "therefrom. A peripheral sealing gasket 39 is provided on the underside of the plate 27 for sealing the chambers 22 to the matrices 14, during the delivery of the material from the cart to the cavities 19. To this end, the cart is carried by a plurality of flanged wheels 31 on suitable spring mounted carriers 32. The cart is lowered against the action of the spring carriers 32 by a pair of presser bars 33 on the press 10 engaging suitable rarn buttons 34 on the opposite sides of the top of the cart.

Upstanding from the bottom wall 24 is aperipheral wall 35 with a central dividing wall 35, both defining the lateral boundaries of, and interconnecting through a common opening, the loading spaces 22. The top of the cart 'is closed by a cover 37 having a pair of circular openings 38 aligned one each with each of the chambers 22. A pair of horizontally swinging valve plates 39 are pivotally mounted on the cover for selectively closing the openings 38. The valve plates are selectively operated by suitable means, such as pull rod 40 acting through a conventional pivot mechanism 41. Pressurized air is introduced into .the chambers 22 by suitable inlets 42 opening through the Thus, the 7 material may be delivered through the chutes 23 and side wall 35 at the opposite sides of the cart.

tation of the material. ments on the air motor, the pins of one bar in each chamber are preferably offset approximately 90 degrees rotabrought to the transferring position overlying the matrix cavity 19'and the presser bars 33 are actuated, lowering the cart body to engage the seal 30 with the matrices 14, and thereby effecting a sealing connection between the respective loading chambers 22 and the respective cavities 19 through the blow tubes 25 extending through the bottom of the cart.

The pulverulent ceramic or refractory material is caused to pass downwardly from the loading chambers 22 by means of high pressure air delivered through the inlets 42, which in passing through the loading chambers causes the material to be entrained therein and be carried with the air downwardly into the matrix cavities. To preclude undesirable bridging of the material, as occurs in conventional loaders for pulverulent material of this type, agitating means are provided in the form of a pair of horizontal bars 43 extending longitudinally through each of the loading chambers 22. Each of the bars carries a plurality of agitator pins 44 extending diametrically therethrough, at an acute angle to the axes of the bars, and interconnected at their'extremities by a thin wire 44a. The bars are rotated about their axes by a chain drive 45 driven by a suitable air motor 46 and a driven sprocket 47. The chain drive 45 is engaged with a plurality of idler sprockets 48 in circuitous fashion, so as to cause respective reverse rotation of the bar pairs in each of the loading chambers providing improved agi- To minimize the power requiretionally, relative to the pins of the other bar. Thus, as the high pressure air withdraws the material from the loading chambers 22, the agitators effectively preclude bridging of the material assuring uniform delivery of the material to the matrix cavities, and thereby providing improved uniform homogeneous distribution of the material in the compacted masses.

' To further assure uniform distribution of the material in the air streams, the air motor 46 is preferably reversed a number of times during the delivery of the material from the loading chambers to the matrix cavities. Any suitable well known means may be provided for effecting the reversal automatically seriatim as desired.

. As theair passes from the loading chambers through the blow tubes 25 downwardly into the cavities 19, it delivers the material to the bottom of the matrix cavities and then is caused to make a 180 degree turn to be exhausted through the perforated plate 27 and screen 28 to the space 26. As a result of this turn of the air,

the entrained material effectively completes a separation therefrom and is thereby deposited in a continuous manner from the bottom to the top of the cavity. Thus, the

-matrix cavities may be of effectively minimum depth notwithstanding the fact that the material as originally delivered from the chute 23 and carried by the air streams has a relatively low bulk density.

When the cavities 19 are filled to the desired level with the material, the delivery of the air is automatically discontinued. The loading chamber is then exhausted through the inlets 42 by a suitable three-way air supply valve (not shown) in the air supply system. The presser bars 33 are then withdrawn to permit the cart to be moved from the matrices and back to the loading position of .FIGURE 2. The movement of the cart on the track 20 .by the movement of the upper cross-head 52 downwardly to urge the upper plungers 13 and the upper pneumatic 'hammers 12 downwardly. The upper hammers 12 drive the floating plungers 13 into the upper ends of the cavities 19 to force the material M downwardly therein. At the same time, the bottom hammers 17 drive the floating lower plungers 15 upwardly against the bottom of the material M in the cavities 19. The action of the upper plungers 13 on the material causes it to be maintained in intimatecontact with the top of the lower plungers 15, and the hammering of the plungers is continued until the material is compacted to the mass M having approximately the dimensions illustrated in FIGURE 1.

Upon the completion of the compacting step, operation of the pneumatic hammers 12 and 17 is discontinued, and the upper hammers 12 and plungers 13 are retracted upwardly from the cavities 19. The lower plungers 15 are then moved upwardly through the cavities by operation of the lower cross-head cylinders 16 to raise the lifting beam 18. When the compacted mass M is fully extruded at the top of the matrices 14, the upward plunger movement is stopped, permitting the compacted masses to be removed as desired, such as by hand or by suitable mechanical delivery means (not shown). The lower plungers are then retracted downwardly, thereby reestablishing the press it) for a subsequent loading operation.

Thus, the invention comprehends an improved method of compacting the ceramic or refractory material permitting concurrent formation of a plurality of masses M, each of which is uniformly homogeneous. The invention further comprehends an improved method wherein the compacting is quickly and efiiciently effected, permitting substantial improvement in the rate of production, and, thus, effectively minimizing costs in this highly competitive field. While the invention has been disclosed previously with reference to ceramic or refractory material, it is obvious that it may be equally well applied where the material comprises light-weight particulate material such as expanded shale and the like, as well as heavy particulate material such as clay, metal ores, and the like, The resultant final compacted mass has improved green and fired strength.

The term high particle density as used herein is defined as an arrangement wherein the particles are closely associated. Thus, light-weight, medium weight, or heavy particles may be compacted by this invention equally well to form the high particle density mass.

While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. The method of forming a high particle density mass of ceramic material, refractory material, and the like, comprising the steps of: placing the material in a loading chamber; agitating the material in the loading chamber while concurrently passing air therethrough to entrain the material in the air; passing the air and entrained material downwardly from the loading chamber into a compacting chamber, said agitation being arranged to pre clude formation of continuous direct air passages through the material whereby only air with said entrained material may pass downwardly into the compacting chamber; extracting the material from the air in the compacting chamber by reversing the air flow; exhausting the air from the compacting chamber at the top thereof; compacting the material in the compacting chamber by applying compacting forces to boundary portions thereof to form a compact having sufficient green strength to permit removal thereof fully from the means defining the compacting chamber.

2. The method of claim- 1 wherein the loading chamber has a height substantially less than its horizontal extent and the agitating of the material is mechanically ef- 5 fected by moving an agitating member through the mat'erial.

3. The method of forming a high particle density mass of ceramic material, refractory material, and the like, comprising the steps of: placing the material in a loading chamber; agitating the material in the loading chamber while concurrently passing air 'therethrough to entrain the material in the air; passing the air and entrained material downwardly from the loading chamber into a compacting chamber; extracting the material in the compacting chamber by reversing the air flow; exhausting the air from the compacting chamber at the top thereof; applying plungers to the top and bottom of the material in the compacting chamber; forcing the plungers toward each other to compact the material to form a compact having suificient green strength to permit removal thereof fully from the means defining the compacting chamber.

4. The method of forming a high density mass of particulate material comprising the steps of: providing means defining a compacting chamber; entraining particulate material in a stream of fluid and delivering the fluid carrying the entrained material into the chamber; discharging the fluid from the chamber while causing the entrained material to remain therein; compacting the material remaining in the chamber to form a compact having sufiicient green strength to permit removal thereof fully from the means defining the compacting chamber; and removing the compact fully from the chamber defining means.

References Cited in the file of this patent UNITED STATES PATENTS 15 2,270,829 Wellnitz Jan. 20, 1942 2,611,938 Hansberg Sept. 30, 1952 2,665,461 Rodgers -a Jan. 12, 1954 2,798,266 Herbruggen July 9, 1957 2,905,988 La Beau Sept. 29, 1959

Claims (1)

1. THE METHOD OF FORMING A HIGH PARTICLE DENSITY MASS OF CERAMIC MATERIAL, REFRACTORY MATERIAL, AND THE LIKE, COMPRISING THE STEPS OF: PLACING THE MATERIAL IN A LOADING CHAMBER; AGITATING THE MATERIAL IN THE LOADING CHAMBER WHIL CONCURRENTLY PASSING AIR THERETHROUGH TO ENTRAIN THE MATERIAL IN THE AIR; PASSING THE AIR AND ENTRAINED MATERIAL DOWNWARDLY FROM THE LOADING CHAMBER INTO A COMPACTING CHAMBER, SAID AGITATION BEING ARRANGED TO PRECLUDE FORMATION OF CONTINUOUS DIRECT AIR PASSAGES THROUGH THE MATERIAL WHEREBY ONLY AIR WITH SAID ENTRAINED MATERIAL MAY PASS DOWNWARDLY INTO THE COMPACTING CHAMBER; EXTRACTING THE MATERIAL FROM THE AIR IN THE COMPACTING CHAMBER BY REVERSING THE AIR FLOW; EXHAUSTING THE AIR FROM THE COMPACTING CHAMBER AT THE TOP THEREOF; COMPACTING THE MATERIAL IN THE COMPACTING CHAMBER BY APPLYING COMPACTING FORCES TO BOUNDARY PORTIONS THEREOF TO FORM A COMPACT HAVING SUFFICIENT GREEN STRENGTH TO PERMIT REMOVAL THEREOF FULLY FROM THE MEANS DEFINING THE COMPACTING CHAMBER.

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