US2025053A - Method of and apparatus for molding pulp articles - Google Patents

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Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
  • D21J7/00—Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould

Definitions

• This invention relates to theart of molding hollow articles of paper pulp, and more particularly to articles which have a relatively small opening and which may have irregular shapes.
• a suitable mold for the molding of articles as desired, the dilute pulp stock being introduced into the mold through a suitable nozzle which is preferably constricted atits discharge orifice so as to increase the velocity of the pulp stream as it enters the mold.
• This nozzle preferably projects downwardly into the interior of the mold a substantial distance toward the bottom thereof.
• the exterior diameter of the end portion of the nozzle may also be made as large as possible for the purposes hereinatfer set forth.
• Figure 2 is a diagrammatic sectional view of similar apparatus slightly modified.
• Figure 3 is a view similar to Figure 2 showing another modification.
• Figure 4 is a portion of Figure 1 shown on a larger scale.
• Figure 5 is a fragmentary sectional view of molding apparatus for an article of another shape
• Figure 6 is a conventional sectional view of a diiferent shape of mold and nozzle for the same.
• Figure 1 illustrates portions'of an apparatus for molding hollow pulp articles, such apparatus including a suitably supported member II! from which swingably depend a number of mold sup: ports ll each of these supports having a section 10 I2 of a mold.
• Suitable apparatus a portion of which is indicated at I3, is provided to swing the members ll together to form a complete mold, and to swing them outwardly to discharge a molded article.
• the moldsections l2 are each lined with a suitable screen If), which may be of woven wire, perforated sheet metal, or any other equivalent structure.
• a bottom member l6 may be provided to cooperate with the lateral members l2 so as to complete the shape of the mold, this member It being adapted to be moved downwardly when the members 15 are swung apart for the discharge of the molded article.
• a supply pipe 20 projects from a suitable vat or tank 2
• the supply pipe 20 maybe provided with a valve 22 of any suitable structure to shut olf the supply of pulp when desired.
• An auxiliary pipe 25 may lead into the pipe 20 below the valve 22 for the introduction of compressed hot or cold air, steam, or other fluid into the pipe 20, a valve. 26 being'pro'vided in the pipe 25 to control the fluid therein.
• the screen mold l5, shown in Figures 1 to 4 has, by way of example, the shape of a conventional cylindrical bottle with a neck portion of considerably smaller diameter than the body portion.
• a supply nozzle 30 projects downwardly from the supply pipe 2
• the external diameter of this nozzle is necessarily limited to a size equal to the inner diameter of the mouth of the bottle to be molded since the nozzle must be retracted from each molded bottle after it has been formed.
• a supply pipe 20 of substantial interior diameter is preferably employed.
• the necessary reduction in diameter from the pipe 20 to the nozzle 30 is preferably made by one or more internal tapers as at 3
• the nozzle In the molding of bottles or other figures with comparatively narrow portions, the nozzle must not only be small enough to be withdrawn from the mouth of the molded article, but sufiicient clearance must be provided between the neck portion of the mold and the adjacent wall of the nozzle so that there can be free access of pulp stock to the uppermost end of the interior of the mold for the deposition of pulp at the uoper end or mouth of the molded article.
• the body portion of the molded article is of substantially greater diameter than the neck portion, it is preferred to employ a nozzle having its lower portion of maximum diameter so as to reduce as far as possible the clearance between the lower portion of the nozzle and the adjacent portions of the mold.
• the lower portion of the nozzle 30 may be formed with a thickened wall so that the exterior diameter of this portion of the nozzle is as large as possible consistent with the removal of the nozzle through the mouth of the molded article.
• the wall may be spun outwardly as illustrated at 36 in Figure 3 so as to provide a maximum exterior diameter for the portion of the nozzle opposite the body portion of the mold l5.
• the bore thereof is constricted as at 31 to form a reduced orifice 38.
• a dilute aqueous suspension of paper pulp is supplied at suitable pressure from the tank 2
• the mold is quickly filled with stock and is maintained completely filled for a period of a few seconds, during which time white water escapes through the screen and through the pulp mat which is thereby formed on the inner surface of the screen.
• the valve 22 is closed and the valve 26 is immediately opened for the introduction of compressed air, steam, or other gas or vapor through the nozzle 30.
• the reduced orifice 38 increases the velocity of the air stream which enters the body of pulp stock still remaining in the mold.
• the air jet instantly drives the body of aqueous pulp up into the upper portion of the mold.
• the pressure of the air which may be of the order of 60 pounds or so at the gage, quickly drives out the white water of the residual stock through the screen mold.
• the sweeping action of the air which elevates the residual stock to the upper portion of the mold is augmented by the enlarged external diameter of the lower portion 35 or 36 of the nozzle 30, his enlargement of the nozzle decreasing the clearance between the surface of the mold so as to increase the velocity of the upward flow of the stock.
• the degree of taper of the collar 40 is determined experimentally, but it is found that such a collar, if suitably tapered, results in the 20 depositing of the pulp in such a manner thatthe wall portions adjacent to the mouth of the container are of unifonn thickness substantially equal to that or the rest of the molded article.
• is provided, the taper of 25 which difiFers from that of the collar 40.
• is employed in the molding of containers having the shape of a conventional milk bottle with a rounded lip portion 42 and an inward flange 43 adapted to provide a seat for a disk bot- 30 tle cap.
• ensures the molding of a flange 43 with a thickness substantially equal to that of the wall of the container, instead of a thin fin or feather which has characterized earlier attempts to mold a container of this shape without 85 the use of a member such as the collar 4
• Figure 6 is a conventional showing of a screen mold 45 of special shape, together with a suitable nozzle 46 for the introduction of pulp stock into the mold.
• This nozzle has a constricted passage 40 41 near its lower end to introduce the stock and air at relatively high velocity for the purposes hereinbefore set forth.
• the lower tip of the nozzle may be internally flared as at 48 so as to permit the stream of stock to spread as it enters 45 the mold so as to distribute the pulp more evenly on the surface of a screen mold having a shape of the type illustrated in Figure 6.
• a characteristic feature of our invention includes the introduction of the pulp and compressed air through the reduced neck portion of the mold and through a duct having a restricted discharge orifice located within the mold at a point sufiiciently removed from the 5 neck entrance to insure the uniform distribution of the pulp through the mold.
• a hollow screen mold having an opening or mouth therein, a supply nozzle projecting 0 through said opening into said mold, a ring on said nozzle member at the mouth of the mold, said ring having a thickness tapering toward the tip of the nozzle and partially filling the clearance between the sides of the mold adjacent to the mouth and the sides of the nozzle, and means for supplying a stream of stock to said nozzle.
• Molding apparatus for hollow pulp articles comprising a hollow screen mold having an open-' ing or mouth therein, a supply nozzle projecting through said opening into said mold, the end portion of said nozzle within the mold having a bore tapering in diameter toward the orifice thereof and an external diameter greater than that of the adjacent portion of the nozzle, a ring on said nozzle member at the mouth of the mold, said ring having a thickness tapering toward the tip of the nozzle and partially filling the clearance between the sides of the mold adjacent to the mouth and the sides of the nozzle, and means for supplying a stream of stock to said nozzle.
• Apparatus for molding bottle-shaped paperpulp articles which comprises a hollow mold lined with a foraminous screen with a body portion, a relatively narrow neck portion and an inward flange to form the lip of the molded article, a. supply pipe for pulp stock extending into the interior of said mold, and a ring on said supply pipe opposite the upper part of said neck portion of the mold, said ring tapering downwardly in thickness so as to deflect ascending stock outwardly against said upper part of the mold.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Paper (AREA)
• Containers Having Bodies Formed In One Piece (AREA)

Description

Priority Applications (1)

Applications Claiming Priority (1)

Publications (1)

Family

ID=24700563

Family Applications (1)

Country Status (1)

Cited By (5)

• 1933
  • 1933-05-26 US US672918A patent/US2025053A/en not_active Expired - Lifetime

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