US3190791A - Pulp molding machine with molds forming an endless chain - Google Patents

Description

J. M. POTTER June 22, 1965 PULP MOLDING MACHINE WITH MOLDS FORMING AN ENDLESS CHAIN Filed Dec. 4, 1961 2 Sheets-Sheet 1 m a m 4 W WP elm 1 M g l 1 5 M 4T a N 3 WM B M 5 MY w 3,190,791 PULP MOLDING MACHINE WITH MOLDS FORMING AN ENDLESS CHAIN J. M. POTTER June 22, 1965 2 Sheets-Sheet 2 Filed Dec. 4, 1961 INVENTOR. J4/7E5 P0775? BY 80% A U M50-u.

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United States Patent 3,196,791 PULP MGELDTNG MACHME WTTH MQLDS FORMING AN ENDLESS CHAIN James M. Potter, Flagstaff, Ariz., assigner to Bankers Life & Casualty Company, Chicago, TEL, a corporation of Illinois Filed Dec. 4, 1961, Ser. No. 156,668

4 Claims. (til. 162-219) The present invention relates generally to pulp molding and, more particularly, it relates to pulp molding apparatus in which molded articles are formed as an integral portion of a continuous web.

Molded pulp articles comprise items formed from wood pulp or other pulps. Well known examples of such molded pulp articles include egg cartons and pie plates.

Various means for forming molded pulp articles have been known and used for many years. The most common apparatus used for producing such articles comprises a rotating carrier provided with porous dies around its periphery. The dies are suitably contoured to provide the desired shape for the article being molded.

A reservoir disposed beneath the carrier contains a quantity of stock, which is a suspension of the fibers from which the article is to be formed, and, as the carrier rotates, the dies are submerged in the stock for a prede termined period or" time. Vacuum is applied through the submerged dies, thereby depositing the fiber of the exterior of the die;

One problem associated with pulp forming apparatus heretofore known has been the difiiculty of handling individual wet pulp articles from the forming dies. A wet pulp article is structurally weak, and, if it is not continuously supported in the desired configuration, the article will tend to deform. Accordingly, it has heretofore been necessary to provide support for each article until sufiicient water has been removed therefrom to render it self-Supporting. This has required asubstantial investment in means for transporting the individual wet pulp articles through drying means, and has imposed limitations on productive capacity of the apparatus.

It is a primary object of the present invention to provide improved pulp forming means. A more particular object of the present invention is to provide pulp form ing means in which is formed a continuous web which includes molded pulp articles as an integral portion thereof. Other objects and advantages of the present invention will become apparent from the following description and drawings, in which:

FIGURE 1 is a schematic fragmentary elevational view, partly broken away, of apparatus suitable for the practice of the present invention;

FIG. 2 is a schematic fragmentary plan view, partly broken away, of the apparatus shown in FIGURE 1; and

FIGURE 3 is an enlarged perspective view of a portion of the conveyor which is a part of the apparatus illustrated in FIGURES l and 2.

In accordance with the present invention, there is provided appartus on which molded pulp articles are produced as an integral portion of a continuous web. The web is partially dried on the apparatusand, thereafter, has suflicient strength to be handled without means for individually supporting the molded pulp articles.

There is illustrated in FIGURE '1 pulp forming apparatus 5 which comprises a frame 7 fabricated from suitable beam and channel members for-carrying various components on the apparatus including a conveyor 13. The conveyor'13 is trained around and between sectioned drums a, 15b, and 150, and idler drums 17a and 17b. Stock reservoirs 19a, 19b, and 19c are also carried on the frame, and are located below each of the sectioned drums 15a, 15b, and 150. The stock reservoirs are supplied with stock from a chest (not shown) through a pipe 20. Level control apparatus may be in each reservoir 1%, 19b, and 190.

The idler drums 17a and 1712 are disposed on the frame 7 between the sectioned drums 15a, 15b, and 150, and support the conveyor 13 in such a manner that the conveyor is in contact with the peripheral surface of the drums 15a, 15b, and 150, while it is immersed in the reservoirs 19a, 19b, and 19c.

It will be seen that the longitudinal axes of the sectloned drums 15a, 15b, and 15c are generally horizontal, and parallelto each other; with the middle drum 15b having its axis below the axes of the drums 15a and so that the upper portion of the drum 15b does not interfere with the upper run of the conveyor 13 between drums 15aand 150. The longitudinal axes of the idler drums 17a and 17b are parallel to the axes of the sectioned drums 15a, 15b, and 15a and are on a level with drums 15a and 150. The idler drums are smaller in diameter than the sectioned drums 15a, 15b, and 150 so that they do not interfere with the upper run of the conveyor 13.

As seen more particularly in FIGURE 3, the conveyor 13 comprises a plurality of perforated sections 21, a Fourdrinier wire 22 which is trained over the perforated sections, and porous dies 23 removably mounted on the perforated sections and wire 22. Each perforated section includes side links 24 and 25 and a perforated platen 27 attached to the side links and extending therebetween. The side links are disposed perpendicular to the longitudinal axes of the sectioned drums 15a, 15b and 15c. The end links 24 and 25 of the perforated sections 21 are joined by pin connectors 29 to provide an endless conveyor 13, and including openings 26 which engage teeth on the drums.

Since each of the sectioned drums 15a, 15b, and 150 is constructed substantially the same, they will be particularly described with reference to drum 15a and corresponding parts will be similarly numbered. The sectioned drum 15a comprises a tubular shaft 31 rotatably supported in journals 32. The drum further comprises polygonal end plates 33 and 35 secured to the shaft and axially extending frames 37 located at the periphery of the end plates 33 and 35. Gear-type teeth 41 are attached to the frames 37 which engage the openings 26 in the side links 23 and 25 of a perforated section 21.

The frames 3'7 are generally rectangular in shape and are proportioned to accommodate the area of the perfo rated sections 21 of the conveyor 13. In operation, the perforated sections provide a cap for the frames when the conveyor enters the reservoirs 19m, 1%, and 19c and the frames 37 coact with the perforated sections of the conveyor 13 to drive and pull the conveyor through the apparatus of the invention.

The frames 37 of the drum 150, form the outer edges of housings 45. Each housing 45 has outwardly-flaring walls 47 attached to the end plates 33 and 35 and the frame 37. Each housing 45 connects to a pipe or tube 49 at its inner end. The tube 49, in turn, connects to and communicates with the shaft 31.

The tubular shaft 31 of the drum 15a is in communication with a pump or other vacuum producing means (not illustrated), through a vacuum line 58, whereby subatmospheric pressure may be established Within the shaft and in the housings 45. Timed valve means 51 are also provided, whereby the pressure within the housing 45 may be reduced to subatmospheric pressure in timed relation to the rotation of the drum. The valve means 7 51 includes a valve 51a in each tube 49 which is activated by a pinion 5112 which engages a fixed gear 510 connected to the journal 32. The pinions 51b are journalled on the end plate 33 so that as the drum 15a rotates, the

3 valve means is actuated in relation to the rotation. The valve means 51 is timed so that the valve 51a is open and a subatmospheric pressure is established in the housing 45 when the conveyor 13 is in the stock in the reservoir 19, and the pressure is released when the conveyor 13 is out of the reservoir.

As illustrated in FIGURE 1, the conveyor 13 is trained around and between the sectioned drums 15a, 15b, and 150 and the idler drums 17a and 17b. The idler drums are mounted on solid shafts 52 which are rotatably supported in suitable journals 52a, and polygonal end plates 53 secured thereto. Frames 37 are attached to the end plates, and are provided with teeth 41 which engage the slotted openings 26 in the side links 24 and of the conveyor 13.

As illustrated in FIGURE 2, sectional drums 15a and 15c are driven by drive means 1%, comprising a motor 18a, and a gear reducer 18b coupled to the hollow shaft 31 of the drum 15c. Drum 15a is driven by a geared shaft 18c which, in turn, is driven off the journal 32 of drum 150. The sectioned drums are driven in the direction indicated by the arrows in FIGURE 1.

As before indicated, the apparatus of the invention further comprises stock reservoirs 19a, 19b, and 15% disposed beneath each of the sectioned drums 15a, 15b, and 15c. Stock is introduced into the stock reservoirs and is continuously maintained at a level therein whereat the bottom portion of each drum is in the stock. The stock may be continuously recirculated to insure uniformity of composition.

A vacuum box 63 is provided beneath the upper run of the conveyor 13. The vacuum box 63 is disposed beneath the side links 23 and 25 of the perforated sections 21, in closely adjacent relation to the perforated platens 27 of the perforated sections.

A press unit is also provided, as illustrated schematically in FIGURES 1 and 2, through which the conveyor 13 extends, and in which press rolls as, which may be heated or unheated, are disposed. The press rolls have faces which are compatible with the conformation of the particular molded pulp articles being produced.

The Fourdrinier wire 22 (FIGURES 2 and 3) is trained around the sectioned drums'lSa, 15b, and 15c, outside the conveyor 13. The wire 22 is disposed between the side links 24 and 25 of the perforated sections 21 in overlying relation to the perforated platens 27. The wire may be of a mesh suitable for the deposition of the particular desired pulp thereon. It should be understood that any porous fabric which is capable of functioning in the same manner as a Fourdrinier wire may also be utilized in the practice of the present invention.

Porous dies 23 are provided on each perforated section 21. The dies are attached to the platen 27 of a perforated section 21 in overlying relation to the Fourdrinier wire 22. The dies 23 are fabricated from a sufficiently porous material to allow passage of Water therethrough. The dies are shaped to provide the desired molded pulp article, and, in the illustrated apparatus, dies are provided which are suitable for forming egg cartons and pie plates.

As illustrated schematically in FIGURE 2, there is also provided a drying unit 73, and a slitting and cutting unit 75 to provide individual molded pulp articles.

In operation, stock comprising pulp of the desired type is introduced into the stock reservoirs 19a, 19b, and 190. In the illustrated apparatus, comprising three stock reservoirs, a 3-ply deposit of pulp may be obtained. Each of these plies may comprise the same type of pulp, or, alternatively, pulp having different properties may be applied in all or any of the plies.

As the pulp deposition drums 15a, 15b, and 150 are rotated, in the direction of the arrows, the perforated sections 21 of the conveyor 13 are successively submerged in stock contained in the stock reservoirs 19a, 19b, and 190. In particular, when a perforated section 21 is at position A on pulp deposition drum 19a in FEGURE l, the perforated platen 2'7 of that perforated section is substantially completely submerged in stock. At this point, the pressure within the housing 45 which is in contact with that platen is reduced to subatmospheric pressure by timed valve means 51. Stock is thereby forced through the porous dies 69 or 71, the Fourdrinier wire 22., and the perforated platen 27. Pulp from the stock is thereby deposited over the porous die and the Fourdrinier wire in a continuous web.

Subatmospheric pressure is maintained in the housing 45 until the perforated section 21 reaches position B in FIGURE 1, whereupon valve means 51 closes valve 51a, and the pressure in the housing returns to ambient conditions. It will be seen that pulp is thereby deposited successively upon the porous dies 69 and 71 and the wire 22 to provide a continuous web which includes molded pulp articles as an integral portion of the web.

Additional plies of pulp are deposited on the die and the wire in like manner at drums 15b and 150. The web so formed is thence transported by the conveyor 13 over the vacuum box 63 and into the press unit 65.

In this connection, it may be desirable, under some conditions and with some pulp articles, to remove a substantial portion of the water from the web. Under these conditions, the press rolls disposed in the press unit 65 are utilized, and the rolls may also be heated to remove additional water from the web. Under other conditions, and with other pulp articles, it may be desirable to remove less water from the web, and water removal may be accomplished by the vacuum box alone.

After the desired amount of water has been removed from the web at the vacuum box and press unit 65, the web is removed from the Fourdrinier Wire 22 and the porous dies 23 and transported to the drying unit 73 and to the slitting and cutting unit 75 to provide individual molded pulp articles. In this connection, the web is lifted at sectioned drum 15a. One method for effecting this lifting comprises the introduction of compressed air to a housing 45 of the pulp deposition drum 15a as a perforated section 21 of the conveyor 13 reaches position C in FIGURE 1. The timed introduction of compressed air in this manner may be accomplished by suitable timed valve means, in accordance with known methods and apparatus.

Since the molded pulp articles comprise an integral portion of a continuous web, they are effectively and etficiently transportable to subsequent operations and equipment. As an example of the practice of the present invention, apparatus illustrated is operated at a conveyor speed of feet per minute, and the web is transported at this speed to the drying unit and the slitting and cutting unit '75. Thus, the formation of a continuous web is an important feature of the present invention, enabling more rapid and efiicient operation than in pulp forming apparatus heretofore known.

Thus, there is provided improved pulp forming apparatus, on which is formed a continuous web which includes molded pulp articles as an integral portion thereof. In accordance with the present invention molded pulp articles are produced economically and efficiently, resulting in substantial benefits over apparatus heretofore known.

The foregoing description will suggest various modifications to those skilled in the art. Such modifications are deemed to be within the scope of the claims of the present invention.

Various features of the present invention are set forth in the following claims.

What is claimed is:

1. Pulp forming apparatus, comprising a plurality of drums, the longitudinal axes of said drums being generally horizontal and substantially parallel to each other, an

endless conveyor trained around and between said drums, said drums being partially submerged in stock, said conveyor comprising a plurality of perforated sections, a porous fabric on said perforated sections, and a porous die on said conveyor in overlying relation to said fabric, drive means associated with said drums to rotate said drums and transport said conveyor, whereby parts of said conveyor are periodically submerge-d in stock, vacuum means connected to said partially submerged drums whereby pulp is successively deposited on said porous die and said fabric as a continuous web during the periods of submergence, and press and drying means to dry the web.

2. Pulp forming apparatus, comprising a plurality of drums, the longitudinal axes of said drums being generally horizontal and substantialy parallel to each other, an endless conveyor trained around and between said drums, said drums being partially submerged in stock, said conveyor comprising a plurality of perforated sections, a porous fabric on said perforated sections, and a porous die on said conveyor in overlying relation to said fabric, drive means associated with said drums to rotate said drums and transport said conveyor, whereby parts of said conveyor are periodically submerged in stock, vacuum means connected to said partially submerged drums whereby pulp is successively deposited on said porous die and said fabric as a continuous web during the periods of submergence, press and drying means to dry the web, and cutting and trimming means to provide individual molded pulp articles from the web.

3. Pulp forming apparatus, comprising a plurality of drums, the longitudinal axes of said drums being generally horizontal and substantially parallel to each other, an endless conveyor trained around and between said drums, said drums being partially submerged in stock,

said conveyor comprising a plurality of perforated sections, a Fourdrinier wire on said perforated sections, and a porous die on said conveyor in overlying relation to said wire, drive means associated with said drums to rotate said drums and transport said conveyor, whereby parts of said conveyor are periodically submerged in stock, vacuum means connected to said partially submerged drums whereby pulp is deposited on saidporous die and said Fourdrinier wire as a continuous web during the periods of submergence.

4. The method of manufacturing molded pulp articles comprising the steps of disposing a porous die having the desired conformation upon an endless porous fabric, conveying the die and the fabric through a quantity of stock while maintaining vacuum conditions on the side of the fabric opposite the die, thereby depositing a layer of pulp on the die and the fabric to provide a molded pulp article as an integral portion of a continuous web, drying the web on the forming die, and then separating the continuous web from the die and fabric, the forming and transporting of the molded pulp article through the processing steps being conducted while maintaining the die dimensions constant and while flexing the fabric intermediate the dies.

References Cited by the Examiner UNITED STATES PATENTS 1,661,727 3/28 Koppelman et a1. 162-392 1,677,905 7/28 Salisbury 162388 1,719,819 7/29 Koppelman 162388 2,592,518 4/52 Magnani 162-367 DONALL H. SYLVESTER, Primary Examiner.

RICHARD D. NEVIUS, WILLIAM B. KNIGHT,

Examiners.

Claims (2)

1. PULP FORMING APPARATUS, COMPRISING A PLURALITY OF DRUMS, THE LONGITUDINAL AXES OF SAID DRUMS BEING GENERALLY HORIZONTAL AND SUBSTANTIALLY PARALLEL TO EACH OTHER, AN ENDLESS CONVEYOR TRAINED AROUND AND BETWEEN SAID DRUMS, SAID DRUMS BEING PARTIALLY SUBMERGED IN STOCK, SAID CONVEYOR COMPRISING A PLURALITY OF PERFORATED SECTIONS, A POROUS FABRIC ON SAID PERFORATED SECTIONS, AND A POROUS DIE ON SAID CONVEYOR IN OVERLYING RELATION TO SAID FABRIC, DRIVE MEANS ASSOCIATED WITH SAID DRUMS TO ROTATE SAID DRUMS AND TRANSPORT SAID CONVEYOR, WHEREBY PARTS OF SAID CONVEYOR ARE PERIODICALLY SUBMERGED IN STOCK, VACUUM MEANS CONNECTED TO SAID PARTIALLY SUBMERGED DRUMS WHEREBY PULP IS SUCCESSIVELY DEPOSITED ON SAID POROUS DIE AND SAID FABRIC AS A CONTINUOUS WEB DURING THE PERIODS OF SUBMERGENCE, AND PRESS AND DRYING MEANS TO DRY THE WEB.

4. THE METHOD OF MANUFACTURING MOLDED ULP ARTICLES COMPRISING THE STEPS OF DISPOSING A POROUS DIE HAVING THE DESIRED CONFORMATION UPON AN ENDLESS POROUS FABRIC, CONVEYING THE DIE AND THE FABRIC THROUGH A QUANTITY OF STOCK WHILE MAINTAINING VACUUM CONDITIONS ON THE SIDE OF THE FABRIC OPPOSITE THE DIE, THEREBY DEPOSITING A LAYER OF PULP ON THE DIE AND THE FABRIC TO PROVIDE A MOLDED PULP ARTICLE AS AN INTEGRAL PORTION OF A CONTINUOUS WEB, DRYING THE WEB ON THE FORMING DIE, AND THEN SEPARATING THE CONTINUOUS WEB FROM THE DIE AND FABRIC, THE FORMING AND TRANSPORTING OF THE MOLDED PULP ARTICLE THROUGH THE PROCESSING STEPS BEING CONDUCTED WHILE MAINTAINING THE DIE DIMENSIONS CONSTANT AND WHILE FLEXING THE FABRIC INTERMEDIATE THE DIES.

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