US2098008A - Method of and apparatus for molding articles of paper pulp - Google Patents

Description

Nov. 2, 1937. H. v. MITCHELL METHOD OF AND APPARATUS FOR MOLDING ARTICLES OF PAPER PULP 5 Shee ts-Sheet 1 Filed Jan. 12, 1935 Nov. 2, 1937. H. v. MITCHELL METHOD OF AND APPARATUS FOR MOLDING ARTICLES OF PAPER PULP Filed Jan. 12, 1935 5 Sheets-Sheet 2 Nov. 2, 1937.

H. V. MITCHELL METHOD OF AND APPARATUS FOR MOLDING ARTICLES OF PAPER PULP 5 Sheets-Sheet 3 Filed Jan. 12, 1935 I Nova, 2, 1937. H. v. MITCHELL 2,098,008

METHOD OF AND APPARATUS FOR MOLDING ARTICLES OF PAPER PULP Filed Jan. 12, 1935 5 Sheets-Sheet 4 w M 44 Z7 i1 fi/ Mo //f w w W W Nov. 2, 1937. H. v. MITCHELL METHOD OF AND APPARATUS FOR MOLDING ARTICLES OF PAPER PULP Filed Jan. 12, 1935 5 Sheets-Sheet 5,

jfZWfii ZZZ/ WwqyMzzZM (3 w 2 MW g Patented Nov. 2, 1937" UNITED 'ISTATE'S' PATENT OFFICE Mia-mon- OF AND APPARATUS FOR MOLD- ING ARTICLES OF PAPER PULP Harvey v. Mitchell, Bridgeport, at... Application January 12, 1935, Serial No. 1,478

' 16 Claims. .(CI. 92-58) This invention relatesto a method of and apparatus for molding hollow articles of paper pulp. It has been the practice to mold such articles by filling a. hollow foraminous mold with a dilute paper pulp stock and keeping the mold filled with stock until a sufficient wall thickness of pulp is accumulated against the inner surface of the mold, whereupon the supply of pulp stock is cutoff and the residual liquid in the mold is 10 expelled by air or steam pressure which compacts and partially dries the pulp mat which has been deposited against the inner surface of the mold so that the article can be handled. The article is then removed from the mold and is subjected to further drying and other treatment as desired. For commercial success-in the manufacture of molded pulp articles, speed of pro duction is a vitally important factor. In methods of molding pulp articles as now practiced, a very dilute pulp stock must be employed to get satisfactory results. This means that a comparatively large volume of water must pass through the mold and the pulp mat deposited thereon in the course of molding. an article. Consequently, the molding cycle -must include a time interval sufficient for the discharge of this water.

It is an object of the present invention to shorten the necessary time required for the molding of an article by diluting the pulp stock which enters the moldwith air instead of extra water, so that the stock enters the mold mixed with air. In order to ensure a proper distribution of pulp fibers over the interior of the mold, the pipe or nozzle through which the stock enters the mold may, according to the invention, be roftated and may also be axially reciprocated.

It is a further object of the invention to provide relatively simple and inexpensive apparatus for molding pulp articles, and to make such apparatus capable of simple adjustments to adapt it, for the requirements of articles of difierent sizes and shapes.

Various other novel and advantageous features will be apparent to one skilled in the art from the disclosure of the invention in the description which follows, and in the drawings, of which Figure 1 is an elevation, partly in section, of apparatus embodying the invention.

Figure 2 is a front elevation of a portionof the same.

Figure 3 is a side elevation of a modified form of the molding apparatus.

Figure 4 is a front elevation of the apparatus shown in Figure 3.

Figure 5 is a sectional view of a portion of the molding apparatus including the pulp valve.

Figure G is a sectional view showing the pulp valve in a diflerent position. I

Figure 7 is a sectional view of the molding nozzle and the motor by which it is rotated.

Figure 8 is a fragmentary sectional view on the line 8-8 of Figure '7.

Figure 9 is a fragmentary sectional view on the line 9-9 of Figure '7.

Figure 10 is a sectional view of a nozzle tip.

Figure 11' is a fragmentary sectional view on the lines ll-ll of Figure 1.

Figure 12 is an elevation of a molding unit, broken away to show interior parts.

Figure 13 is a section on the line I 3-13 of Figure 12.

Figure 14 is an elevation, partly in section, of modified apparatus for controlling the pulp sup- Ply.

Figure 15 is a. development of a portion of the support table for the molds.

Generally speaking, the apparatus which is illustrated as an embodiment of the invention comprises a supply tank for the paper pulp stock of proper concentration. This tank may be supplied with an agitator (not shown) to keep the stock well stirredaccording to usual practice. Charges of pulp stock are drawn from the tank 20 through pipes 2| leading to control valves 22 into a pair of cylinders 25. Whiletwo cylinders 25 are shown, .by way .of illustration, for purposes of rapid production, it is evident that a single cylinder can be employed to mold articles one at a time, or more than two can be provided for simultaneous operation. When the cylinders have drawn in sufiicient charges of pulp stock, the valves 22 are operated as hereinafter explained to permit the discharge of the pulp through tubular nozzles 26 into hollow foraminous molds contained in casings 21. The pulpis drawn into and discharged from the cylinders 25 by the reciprocation of pistons connected to a piston rod 28 driven by suitable power mechanism such as a compressed 'air motor 30. The pulp stock in passing from the cylinders 25 to the nozzles 26 passes through fittings 3| which contain mixing chambers in which the stock is mixed with air supplied through pipes 32 from a reservoir 35 and may also be mixed with any other ingredient in liquid or powdery form such as coloring matter, sizing, coating material, or another variety of pulp-stock, such other ingredient being supplied through pipes 36 from a supply tank 31-. This tank is preferably 66 is thus shifted upwardly so as to rotatethe air tight so that compressed air may be supplied thereto as by a pipe 46, the material in the tank 31 being forced through a pipe 4| to the pipes 36 under pressure. The flow of air through the pipes 32 may be controlled by a valve 42 operated by a cam 43. In like manner, a valve 44 may be operated by a cam 45 to control the fiow of the ingredient supplied from the tank 31. It is not necessary to force material through the pipe 36 by compressed air as the fiow of air from the pipe 32 ordinarily produces a suction at the orifice of the pipe 36, as hereinafter described. The nozzles 26, which enter the molds in the casings 21, are preferably rotated as by suitable motors 56. For this purpose, suitable power means such as air-driven turbines may-be employed, these turbines being connected by flexible connections 5| to the air manifold 35 through driven by a constantly rotating shaft 6|, which,

as shown, is connected by a gear 62 to a pinion 63 which is mounted on a shaft 64 driven through transmission mechanism by any suitable source of power connected by a power belt 66. Y

The portion of the apparatus used for dis charging the pulp stock into the mold is illustrated more particularly in Figures 2, 5 and '7. As shown, each cylinder 25 contains a piston 1| connected by a piston-rod 12 to a cross-head 13.

The piston rod 28 is secured to the cross-head 13 and to a power piston 15 in the motor 36 by reciprocation of the'pistons 1|. As the pistons 1| rise, they draw into the cylinders 25 charges of .pulp stock from the supply tank 26. During this portion of the cycle of operations, the pulpcontrol valves 22- are in the position shown in Figure 5. When the pistons 1| reach the upper endof their stroke, a finger 16 engages the upper of two adjustable lugs 11 and 16 on a control' rod 86, the lower end of which rod is connected to operating arms 6| of the valves 22. The rod valves 22 to the position shown in Figure 6. This shuts off the supply pipes 2| which lead from the tank 26, and connects the cylinders 25 with the molding nozzles 26. The downward stroke of the pistons "1|,which immediately follows, forces the pulp stock through the molding nozzles 26 until the pistons reach the bottom of their stroke, at which point the rod 66 is shifted by engagement of the finger 16 with the lower lug 18, shifting the valves 22 to the position illustrated in Figure 5 During this flow of the stock through the nozzles 26, the nozzles are vertically reciprocated as by connecting rods 62 which are attached to levers 63. These levers are rocked by crank arms 64. which are mounted on a shaft 65 and which engage the levers in slots 66. On the shaft 65 is a pinion 61 meshing with a rack 66 which is a part of or is secured to the piston rod 26. By selecting a pin-5 ion 61 of suitable size, the number of reciprocations of the nozzles 26 for each stroke of the pistons 1| can be determined. The length of stroke of the nozzles 26 can be determined by attaching the upper ends of the rods 62 at selected points on the levers 63, thus varying the eifective length of the levers, or by replacing the crank arms 64 by crank arms of a different length.

As shown in Figure 5, the pulp stock which is discharged from each cylinder 25 through the corresponding valve 22 passes through a nozzle 96 which projects into a mixing chamber 9| in the corresponding fitting 3|. The air pipe 32 opens into the chamber 9|, so that, as the jet of pulp stock issues from the nozzle 96, it is surrounded by air flowing in the same direc-' tion. The mixture of air and pulp stock enters a pipe 92 which leads into the molding nozzle 26 as illustrated in Figure 7. With the mixture of pulp stock and air may be added another ingredient or ingredients supplied through one or more pipes 36, one such pipe being illustrated for each chamber 9|. The rush of air past the orifice of the pipe 36, with or without a stream of pulp stock flowing from the nozzle 96 past the orifice of the pipe 66, not only produces a suction efiect in the pipe 36 but also violently breaks up the stream of such ingredient entering the chamber from the pipe 36 and thoroughly mixes it with the air stream and with the pulp stock if the latter is flowing.

The molding nozzle 26 may be a simple tubular member or may be supplied with a molding tip 95, such, for example, as is illustrated in Figure 10. The molding tip shown in this figure is intended for the molding of relatively small articles or articles having a small opening which easily may be closed later to provide the finished article having a completely closed surface. During the flow of the pulp stock through each nozzle 26, the nozzle is preferably rotated by suitable apparatus such as a turbine 56 having a turbine wheel I66. The speed of rotation of the nozzle may beconsiderable, 4,000 to 10,000 R. P. M. being found suitable. The turbine wheel I66 may be closed in a suitable casing |6| to which is supplied a stream of air, steam, or other suitable fluid through a supply pipe 5| and a restricted passage 62 which forms a high speed jet impinging on the blades of the turbine wheel I66, the power fluid being discharged as through outlet ports I63. Since it is usually desirable to reciprocate the nozzle 26 axially, the motor 56 is adapted to slide on the pipe 92 with the nozzle 26, suitable packing being supplied as at I64 to prevent leakage from the casing |6| along the surface of the'pipe 92. It

is important that the nozzle 26 be freely rotatable on the pipe 92 and that the slight clearance between the surfaces of these nested members be kept clear. To this end, I may provide a small chamber I65 above the upper end of the nozzle 26 within the casing |6|, this chamber acting as an air gland to provide constant pressure at the upper end of the nozzle member 26. The pressure in the chamber 65 is supplied through a duct I66, leading directly from the compressed air supply pipe 5|. A lower chamber I61 may also be supplied with compressed air through a duct I68, the nozzle member 26 having a number' member 26, a connecting rod l'iaving two parts- II4 and H5 may be employed. The part II4 extends from the rocking lever to a disk 6.

The part H5 extends'from the disk I I6'to the motor 50. As indicated in Figure 4, the disk II 6 is provided with a series of holes II1 so that the rods H4 and H5 can be 'operablyconn'ected thereby for any angle of adjustment ofthe nozzle member 26. k

The apparatus thus far described is capable of several simple adjustments. The amount of fiber for each moldedarticle can be varied by altering the length of stroke of each piston-II by modified operation of the motor 30. This is easily done by changing the cam 60. This adjustment should be'accompanied by. suitable adjustment of the lugs 11 and so that the valves 22 will operate at the end of eachstroke. The speed of travel of the pistons 1| may also be regulated at all-points of their 'strokeby suitably shaping the control cam 60 to determine the extent as well as the duration of opening of the valve 56.

The cam 45 may be shaped as desired for the operation of the valve to control the time and rate of admission of an additional ingredient into the mixing chamber 61 to mix with the-stock passing therethrough or to follow the introduction of stock into the mold. For example, a filler, coloring or-si'zing can be injected into the pulp stream at any stage of its period of flow to modify all ofthe pulp'entering the mold or'only the outer or inner layer of pulp in the article formed in the mold. Or, if desired, the-valve 44 may be opened just after the streamof pulp stock is cut off, to-coatjthe inner surface of the molded article. While only one unit for supplying auxiliary ingredientsisillustrated, it is obvious that more can be employed.

The molds'into which the nozzles 26 are introduced are of any desired shape-according to the kind of article to be produced. A typical mold is illustrated in Figures 12 and 13, but it is understood that the-invention is not limited to any particular'size or shape or details of structure of such mold. As shown, the mold unit consists of a cylindricalcasing 21 within which is slidably inserted a circular series of radial vanes I20 supporting the foraminousmold elements which constitute" the mold itself. As'shown. there are two lateral elements. HI and I22 forming halves of the side wall of the mold. Cooperating with these members is a i'oramincu's bottom piece I23 and a top piece I2'4. -Attached to the top piece In order to facilitate rapid production, a table or platform I40 may be provided as indicated in Figures 1 and 11. This table is adapted to rotate about the axis of the shaft 6 I. I40 is preferably driven with a. step-by-step movement, suitable apparatus for this drive being illustrated in Figures 1 and'll. pinion I4I is-mounted on the shaft 64 and drives a gear wheel I42 which is mounted on a shaft I43. Adisk I45 is also mounted on the shaft to be driven thereby, this disk having a pin I46 which engages in successive slots I41 formed in a disk I50, the latter being secured to a sleeve I 5I which is a part of or is secured to the table I40 so that the table is driven with the disk I50. As is evident from Figure 11, the engagement of the pin I46 in successive slots I41 during the rotation of the disk I45 results in rapid indexing 'movements'of the table I40 alternating with con- 26 for a sufficient period forthe molding opera-.

The table To this end, a

tion, and then is shifted. along to be replaced bya fresh mold unit 21-.

It is desirable, according to theinvention, that .the molds 21 be rotated during the molding operation and also after the molding operation, so

that-the water in the pulp stock will be more thoroughly drained by centrifugal force from with its platform I60 is vertically movable and is pressed downwardly both by the weight of the platform I60 with the mold 21 thereon and also by a spring I62 if desired. For the rotation of the spindles I 6| with the platform I60, apair of friction disks I65 and I66 may be mounted on each. spindle I6I, these disksbeing adapted for selective frictional engagement with a central driving disk I10. The driving disk may be constantly rotated by any suitable means. As shown, a gear wheel IN is mounted coaxially therewith and meshes with a pinion I12 mounted on the constantly driven shaft I43. It is evident from Figure 1 that the molds will be rotated unless the spindle is elevated to an intermediate position wherein neither the friction disks I 65 or I 66 is in engagement with the driving disk I10. The speed of rotation of the molds may vary widely according-to the size and shape of the article to be molded, but ordinarily will not exceed 500 to, 600 P. M. The direction of rotation may be with or opposite to the direction of rotation ofthe nozzle 26, as desired, the geared connections with the motor 65 being arranged accordingly. In some cases it may not be practical to rotate the molds, at all. When the molds are rotated, it is desirable that they be rotated continuously while on the platform I except when at the loading station where molds having molded articles therein are removed from the table I40 and are replaced by fresh molds ready to receive the molding nozzle 26. To this end, the platforms I 60 may be partially elevated at the loading station as by a stationary cam member I15, indicated in Figure 15, so that at this stage of the travel of each platform I60 its rotation is temporarily stopped so as to facilitate the into the molding station. At this station it is desirable to elevate the platforms still further so as to move the n'ecks I25 of the molds to telescope over the lower ends of the nozzles 26.

Thus, when the nozzle 26 begins its downward reciprocating motion, its lower end is already within the interior of the mold. For such further elevation of the platforms I60, I may provide an actuating lever I80 pivoted as at I8I and rocked as by a cam I62. As shown in Figure 1, this cam. may be in the form of a disk mounted on the shaft 6| to be driven thereby. The shaft 6| is timed so that it makes a single rotation for every complete molding cycle. The lever I 80 is adapted to engage the lower ends of the spindles I6I whichare directly beneath the molding nozzles 26.

A modified form of drive for the pulp stock piston H is illustrated in Figure 14. Instead of a fluid motor for driving this piston, a crank wheel I85 may be employed, this being connected as by a pitman I86 the upper end of which is radially adjustable on the wheel I85 so as to vary the stroke of the piston 1|. The crank wheel I85 may be driven through bevel gears I81, a connecting shaft I08, 9. second pair of gears I89 and a shaft I90, the latter being operably connected-to the shaft 6| through clutch mechanism such as is indicated in Figure 14. As shown, the shaft 6I drives a clutch member I! which is adapted to mesh with a corresponding clutch member I92 fixed on the shaft I90. The clutch member I9I is moved into and out of engagement with the member I92 as by a sliding member I93 having a cam follower I94 riding on a cam I95 which is secured to the shaft 6|. As the cam I95 rotates with the shaft 6|, the cam follower I94 rides into and out of a depression I96, disconnecting the clutch members I9I and I92 so that the movement of the pistons H is stopped until the cam follower I94 rides out of the depression I96 and throws in the clutch against the pressure of a spring I91.

The operation of the mechanism hereinbefore' described through the molding cycle is as follows. Starting the cycle at the moment when the table I44 has been indexed so as to bring fresh molds 21 into position for the molding operation, the arm I80 is rocked by the cam I82 so as -to elevate the platforms I60 which are beneaththe molding nozzles 26. This elevation is sufiicient to project the lower ends of the nozzles 26 into the interior of the molds. During the indexing movement of the table I40, the pistons II are arrested at a point near to the upper end of their stroke, the valves 22 being at such time in the position shown in Figure 5. The moment the molds 21 are elevated into position telescoping the lower ends of the nozzles 26, the cam 60 actuates the control-valve 56 so as to cause the motor 30 to complete the upward stroke of the pistons 1I. This movement results in shifting of the valves 22 to the position shown in Figure 6. The motor 30 is at once reversed by the cam 60 to force the pistons 1I downward, thus sending a stream of pulp stock down through the mixing chambers 9| and the rotating nozzles 26. Simultaneously with or slightly prior to the actuation of the motor 30, the air valve 42 is opened by the cam 43 so that a stream of air is sent to each of the mixing chambers 9|, so that, when the streams of the pulp stock from the cylinders 25 reach-the mixing chambers, the air is already flowing through the chambers to mix therewith. At present it is not entirely understood just what form the mixture of air and pulp stock takes in the tube 92 and the nozzle 26, The mixture is probably in the form of a foam which travels downwardly at considerable speed and enters the interior of the mold. Some of this foam is caught by the whirling nozzle 26 and is given centrifugal movement so that the pulp flies tangentially from the lower end of the nozzle. During the flow of pulp stock into the mold, the nozzle may be axially reciprocated to assist in the even distribution of the pulp on the interior surface of the foraminous mold. The air pressure and the centrifugal velocity of the pulp discharged from the nozzle tend to compact the mat which is built up against the inner surface of the mold sothat the resulting molded article is well compacted and has a smooth inner surface.

When the pistons 1I reach the lower extremity of their stroke, the valve 22 is shifted from the position shown in Figure 6 to the position shown in Figure 5, so that, as the pistons move upwardly, the cylinders 25 are again charged with pulp stock from the tank 20. Meanwhile the air continues to flow through the nozzles 26, compacting the pulp mat against the interior surface of the mold, thus driving out more and more of the white water from the pulp. This extrac tion of water from the pulp is assisted by the rotary movement of the molds themselves, due to the engagement of the disks I66 with the driving disk I10. When the pistons 1I have reached their position of dwell near the upper limit of their stroke, the cam 60 operates to stop the motor 30 and the cam 43 operates to shut off the flow of compressed air into the molds. The reciprocating mechanism for the nozzles 26 is so arranged that, when the pistons 1| reach this position of dwell, the nozzles 26 are in their extreme uppermost position. The cam I82 operates at thispoint to rock the lever I80 so as to lower the molds 21 clear of the nozzles 26. This brings the disks I65 instead of the disks I66 into contact with the driving disk I10 so that the rotation of the molds is uninterrupted. The table I40 is now indexed to move the molds with freshly molded articles away from the nozzles 26 and to move empty molds into the molding position. The molds thus continue to rotate about their own axes throughout their step-by-step journey around. the table I40 until they again reach the loading position, whereupon their rotation stops so that they can be removed from their platforms I60 and be replaced by fresh molds.

It is evident that various modifications and changes may be made in the methods and apparatus herein described without departing from the spirit or scope of the invention as defined in the following claims.

I claim:-

1. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, passing the mixture through a nozzle into a hollow foraminous mold, and rotating the nozzle on its axis while the mixture is passing therethrough.

2. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, blow ing the mixture through a nozzle into a hollow foraminous mold, and rotating and axially reciprocating said nozzle while the mixture is passing therethrough.

3. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, blowing the mixture-into a hollow foraminousmold,

and rotating said mold while said mixture is entering thereinto.

4. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, blowing the mixture through a nozzle into a foraminous mold, and rotating both said nozzle and mold during the fi'ow of said mixture.

5. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, blowing the mixture through a nozzle into a hollow foraminous mold, and axially reciprocating said nozzle during the flow of stock therethrough.

6. Apparatus of the class described, comprising a nozzle adapted to project into a hollow mold, means for rotating said' nozzle about its axis, a, mixing chamber communicating with said nozzle, a supply pipe for pulp stock projecting into said chamber, and means for supplying air under pressure into the space in the chamber around the end portion of said supply pipe.

7. Apparatus of the class described, comprising a tank for pulp stock, a pump cylinder, 9.. piston reciprocable in said cylinder, a connecting pipe from said tank to said cylinder, a control valve in said pipe, a discharge pipe leading from said valve, said valve beingoperable to connect said pump cylinder alternately with said tank and said dischargepipe, a foraminous mold having a charging opening, a rotatable molding nozzle communicating with said discharge pipe, said nozzle being separable from said mold and insertable into said mold through said opening to close said opening during charging of said mold, and automatic means for operating said valve at the end of each suction stroke of .said piston to connect the pump cylinder with said discharge pipe and at the end of each expulsion stroke to connect the pump cylinder with the tank.

- 8. In molding apparatus for paper pulp, a mixing chamber, a pulp stock supply pipe having an end portion and terminal orifice within said chamber, a discharge pipe leading from said chamber directly opposite said orifice, means for introducing air under pressure into the space in said chamber surrounding said end portion of the supply pipe, and means for injecting another fiuid into said chamber.

9. A method of molding articles of paper pulp, which comprises mixing air and pulp stock, blowing the mixture through a nozzle into a hollow foraminous mold, and causing relative movement between said nozzle and mold during the flow of air and pulp stock mixture whereby to cont ol the distribution of stock over the interior surface of the mold.

10. Apparatus of the class described, comprising a rotatable molding nozzle, means for periodically passing pulp stock through said nozzle, means for axially reciprocating said nozzle during the passage of stock therethrough, means for introducing air through said nozzle, a hollow moldhaving a top orifice adapted to receive and guide said nozzle, conveyor means for moving said mold into and out of molding position beneath said nozzle, means for elevating said mold into telescoped relation with .said nozzle after moving into said molding position and for lowering the mold clear of the nozzle before moving from said molding position and means for rotating said mold while in its elevated position.

11. A method of forming hollow articles of fibrous material which comprises causing a liquid suspension of said fibrous material mixed with a gaseous diluent to flow in a predetermined direction with a whirling movement, and projectingsaid whirling mixture from a restricted opening against the surface of a hollow foraminous mold whereby said fibrous material is restrained on said surface and said liquid and diluent is freed from said fibrous material.

12. A method of forming hollow articles of fibrous material in a foraminous mold which comprises causing a stream of liquid suspension of fibres to flow in a direction substantially parallel with the axis of the mold under a higher pressure than normal gravimetric pressure while simultaneously causing said fibres to whirl in a generally circumferential direction about the axis of said stream whereby to impart energy to said fibres tending to cause them to flow in a direction toward the inner surface of the walls of said foraminous mold and then causing said fibres to flow against said surface with sufficient impact to build a wall of fibrous material thereon and free the major portion of said liquid from said fibres and introducing into the current of the fibrous material a gaseous medium moving in the same general path as said fibrous material.

13. A method of molding hollow articles of paper. pulp, which comprises fiowing pulp stock through a nozzle into a hollow foraminous mold,

rotating the nozzle whereby to throw the pulp and form a wall, and introducing into said flowing pulp stock a substance in gaseous phase and in sufficient quantity to build up a pressure within said mold sufficiently greater than atmospheric, whereby to assist in depositing and compacting said pulp wall.

14. A method of molding hollow articles of paper pulp, which comprises flowing pulp stock through a rotating nozzle into a substantially closed hollow foraminous mold, and supplementing the flow of pulp stock with a fiow or gas in sufiicient quantity to produce a substantial differential pressure between the interior and exterior of said foraminous mold whereby to assist in compacting and drying the paper pulp.

15. A method of molding articles of paper pulp, which comprises mixing a gaseous medium and pulp stock. passing the mixture through a nozzle" into a foraminous mold, rotating the nozzle on its axis while the mixture is passing therethrough, whereby to throw the pulp and form a fibrous wall and introducing into said mold a different material in liquid or suspended form to be retained on said fibrous wall.

16. Apparatus of the class described, comprising a nozzle adapted to project upwardly into a foraminous mold, means for rotating said nozzle about its axis, a supply pipe for pulp stock connected with said nozzle and means for supplying air under pressure through said nozzle HARVEY V. MITCHELL.

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