US1367096A - Manufacture of pulp articles - Google Patents

Description

J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPLICATION F'ILED AUG-15, 1916.

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MANUFACTURE OF PULP ARTICLES.

APPLICATION FILED AUGJE. (EH6.

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J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPucATlon FILED AUGJS, 1916. 1,367,096, Patented FBI). 1, 1921.

4 SHEETS-SHEET 3- ATTORNEYS J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPLICATION FILED AUGJS. I916. 1,367,096. Patented Feb. 1,1921.

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IMVEIVTOR lull ' ATTORNEY-5' A... hmx MN WITNESSES:

UNITED STATES PATENT OFFICE.

JULIAN H. RIVERS, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO UNIVERSAL FIBRE COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

MANUFACTURE OF PULP ARTICLES.

Application filed August 15, 1916.

To all whom it may concern Be it known that I, JULIAN H. Rivers, a citizen of the United States and a resident of Jersey City, county of Hudson, State of New Jersey, have invented certain new and useful Improvements in the Manufacture of Pulp Articles, of which the follow ng, taken in connection with the accompanying drawings, is a specification. I

My invention relates to the manufacture of articles from pulp, such as for instance paper pulp and includes as its objects a method of formation which insures a proper distribution of the suspended particles comprising the pulp wherebyan article of superior structural characteristics is produced, as Well as mechanism of suitable construction to render the carrying out of such method easy and expeditious from a commercially practical standpoint. Other objects will be specifically pointed outor will otherwise appear in the following description of the invention in which the mechaiiism shown in the accompanying drawings will be availed of for illustrative purposes, it being, of course, understood that such other mechanism than that shown may be employed in the carrying out of my invention as may fall within the inventive scope and spirit set forth in the appended claims.

In said drawings Figure 1 is a side elevation of the mechanism which may be employed in accordance-with my invention for the production of hollow articles such as kegs, cans or similar contalners, the mold and certain other parts being shown in vertical section.

Fig. 2 is a plan view of the mold and associated parts of such mechanism, the side walls of the mold being in open position and certain parts being in horizontal section along substantially the line 22 of Fig. 1.

Fig. 3 is a front elevation of the mold and its supporting and associated elements.

Fig. 4. is an enlarged horizontal section of the mold on substantially the line l4 of Fi 5.

Fig. 5 is an enlarged vertical section of the mold, the top, side and bottom walls thereof being in separated relation.

Fig. 6 is an enlarged vertical section of cooperating portions of the side and bottom walls of the mold. I

Fig. 7 is a detail, elevation showing the Specification of Letters Patent.

detail of the construction Patented Feb. 1, 1921. Serial No. 114,944.

latch mechanism for holding the separable parts of the mold in closed position.

Fig. 8 is a plan view, with parts in sect on, of a modified molding mechanism particularly adapted for the production of fiat pulp boards.

Fig. is a side elevation of such modified mechanism, parts being in section.

F g. 10 is a front view thereof.

Fig. 11 is a diagrammatic representation showing the principal parts of such modified mechanism in vertical section, and

Fig. 12 is a vertical section illustrating a thereof.

In connection with either of the two molding mechanisms shown, there is preferably employed a pulp container 13 provided with an agitator 14 mounted on the vertical, power-driven shaft 15 and a pulp, inlet 16 and a pulp outlet 17, the latter being furnished with a suitable valve, such asthe manually operable slide valve18. Connecting with the container outlet 17 below the valve 18 thereof are a plurality of molding mechanism inlet pipes 19, two only of which are shown in Fig. 1, one leading to the molding device of Fig. 1 and the other being broken off as shown, but being in practice connected, if desired, with any suitable molding device, such as a device of the kind shown in Fig. 1 or a device of the kind shown in Figs. 8 to 12 inclusive. A valved drain pipe 20 may be connected with the container outlet 17.

The molding mechanism for hollow articles comprises, generally speaking, separable, perforated mold walls, means for separating them and bringing them together, supporting means and means for controllably connecting the mold with the source of pulp. The mold prop r may b regarded as consisting of the upper wall section'2l, the side wall section 22 and the lower wall or bottom section 23, the latter being secured to and supported upon the studs 24 which rest -upon the bottom of chamber 25. The shell of this chamber is supported by legs or frame 27, and in turn supports table 26. The bottom section 23 is provided with an annular flange 28 projecting under the table 26 and limiting. the movementof said section upwardly from its position upon the studs 24. In order to insure a liquid-tight joint between the bottom beyond the said joint and the bottom of said chamber connects with the molding mechanism inlet pipe 19 through the intermediary of a pipe section 30 provided with a valve 31. The- pipes 30 and 19 are also connected -with a discharge pipe 31 provided with a valve 32.

The chamber 25 is connected with the 1nterior of the mold through a mold entrance pipe 33 extending vertically through the center of the bottom section 23, and is provided with a horizontal baflle 34 which extends across, though spaced from, the discharge end of pipe 30 so as to prevent the pulp admitted to the chamber from spurting into the mold through the pipe 33. The side of the chamber is connected by the pipe 35 with the valved air pressure pipe 36, the upper end of which leads to the upper portion of tank 13 and to a source of compressedair; and with the valved superheated steam pipe 37.

The mold shown comprises three sections provided with foraminated walls to retain the deposited pulp and passages therebehind to allow of the escape of the water or other medium in which the pulp is suspended. These walls and passages may be of any known construction, such for example as that shown and described in my Patent No. 1,174,447, dated March 7, 1916. In the accompanying drawings the surface for receiving the pulp is formed by the fabric 38 backed by the perforated metal sheet 39 set against the supporting ribs 40, (see Figs. 4. 5 and 6) the latter being arranged in any suitable manner to support the filtering surface firmly and at the same time to permit of ready drainage. The spaces between these ribs in the bottom section are connected with the drainage pipe 41 provided with the check valve 42 (Fig. 1) for allowing outward flow only.v The drainage spaces of the top section are connected with the valved and branched central drainage pipe 43, while those of the central section are so constructed as to be in communication with those of the top and bottom sections.

When in closed relation in which the mold parts form a hollow mold with top, bottom and cylindrical sides, the central mold section rests upon and fits into an annular rabbet in the bottom section. and the top section rests upon the central section, being provided with a rabbet which insures a suitable fit between said sections. The central section is preferably made of three segments two of which are hinged to the third by pintles 44, and held closed by the latch 45.

For separating the mold sections and holding them in separated relation a fluid pressure motor 46 is provided. This motor is secured to the underside of the table 26, its piston rod 47 projecting through said table and secured thereabove to the block 48 slidable vertically in the guide 49. Air or water or other fluid under pressure is supplied to the motor cylinder through the pipe 50 provided with a valve 51 so constructed as'to admit fluid into said cylinder in one position of the valve and to allow drainage therefrom into the waste pipe 52 in another position thereof. The block 48 is connected by the forked connecting rod 53 with the levers 54 at an intermediate point thereof, one end of said levers being pivoted at 55 to a stationary upright bracket 56 and the other ends thereof being connected with the top section of the mold through the links 57 and the I-beams 58 secured to said links and to said mold section. The ends of the I-beam structure are guided upon the vertical columns 59 secured at their lower ends to the table 26.

The connecting rod 53 is provided with a pendant rod 60 pivoted at its upper end to the lever near the upper end thereof, the lower end of said pendant rod passing through the eye 61 secured to the central mold section. The extreme lower end of the rod is threaded to accommodate an adjustable nut 62 of such size as not to pass through the eye.

Upon admission of fluid under pressure to the motor 46 through the pipe50, the piston rod 47 and with it the guide block 48 and the connecting rod 53 is caused to rise. The movement of the connecting rod causes the lever 54 to rotate upon its pivot and thus move upwardly the links 57, the I-beam structure 58 and the upper section of the mold until the latter has been swung free of the central mold section. This movement also raises the rod 60, which. however, at first slides freely through the eye 61. Suflicient further movement of these parts raises the nut 62 upwardly until it raises the eye and with it the central mold section, the latter moving upward upon pintles 44 which are carried by bracket 63 fixed to bracket 56. This further movement causes the central section to become separated from, so as to swing clear of, the lower section of the mold and at its limit the mold sections are in the separated relation shown in Fig. 5 and the parts 52, 54, 57 are as shown in dotted lines in Fig. 1. In this position the central section may be unlatched and opened to the position shown in Fig. 2, and the formed pulp article A may be removed easily and without breakage.

Upon manipulation of the valve 51 to allow the cylinder contents of motor to drain into the pipe 52, the parts will descend by gravity to the closed position thereof shown 1n Fig. 1. In order to retain them in this position clutch elements 65 (see Fig. 7) are provided to engage with the front and rear portions of the guide columns 59 which are notched, to facilitate the clutching action. The front pair of clutch elements and the rear pair thereof are moved to effect the turning of the clutch elements 65 upon their lower edges which act as pivots and are supported upon the I-beam structure 58, by the lever system 67 cooperating with the lever 68 ivoted at 69 upon the I-beam structure. he angle pieces 66 connect the clutch elements 65 operating upon one of the columns 59, to those acting upon the other column.

A spring 70 secured at one end of, this lever and at the other end to the I-beam structure tends to pull the inner end of the lever 68 and the lever system 67 downwardly so as to throw the clutch elements in clutching relation to the guides 59. The outer end of the lever 68 is provided with a pull chain 71 adapted to be operated by hand against the spring tension so as to release the clutch elements. The dotted lines of Fig. 7 illustrate this released position. It is, of course, obvious that the clutch elements must be released before the motor 46 is o erated for the purpose of separating the mo d sections.

The modified structure shown in Figs. 8 to 12 inclusive is adapted to produce simul taneously a plurality of flat pulp boards. (The details of this structure form the subject matter of claims presented in my copfnding application, Serial No. 235,109, filed ay 17, 1918.) It consists of a hollow mold structure provided with flat perforated side walls carried upon lateral sections capable of being moved from a closed position of the device in which the side walls cotiperate with the stationary walls to form a hollow chamber, to an open position in which the side walls are brought clear of the other walls, so that the pulp boards formed upon the side walls may be removed therefrom.

The apparatus is supported upon the legs 72 to which the stationary structure consisting of the top wall 73, the end walls 74 and the bottom section walls 75 are secured. Leading into the chamber through the bottom wall thereof is the pulp inlet pipe 76 connected below the valve 77 therein with a pipe leading from a suitable supply of pulpliquor, such as for example the pipe 19 connected with the container 13. Below the connection with pipe 19 there is provided a discharge pipe 78 equipped with a valve 79.

in Fig. 1. Above these the air and steam pigle 135 perforates the wall 7 5.

ach of the side sections consists of a double Wall the inner one 81 of which is perforated and supported against the unperforated outer wall 82 by ribs, shown schematically by the zigzag lines of Fig. 11, which form between them intercommunicating passages through which the pulp liquor may be led into the discharge apertures 83. These draining walls and passages may be generally similar in construction to those of the barrel mold previously described. Behind the imperforate wall 82 is a chamber formed between said wall and the domeshaped exterior side wall 84. The periphery of the inner wall of each side section is provided with a rabbet into which for one side section fits the lateral edges of the angle irons 85 fixedly secured to the stationary top, end and bottom walls of the mold and for the other side section fits the edges of the laterally floating frame 86 between which and the stationary top, end and bottom walls of the mold a liquid-tight joint is provided by a flexible connection such as the corrugated sheet metal connection 87 the peripheral edges of which are secured to said top, end and bottom walls and the inner edges of which are secured to said floating frame, which frame with its attached flexible gasket 87 performs the same function as the edge of plate 23 (Fig. 1) and its flexible corrugated ring 29.

The ends of the side sections are provided with projecting pins 88 upon which book the lateral latch bars 89 when the mold is closed, which bars are secured to the lateral latch rods 90 which extend vertically and are connected at their upper ends with the top latch rods 91. Secured to the underside of these latch rods 91 are the top latches 92 the hooked ends of which coiiperate with the pins 93 carried in the brackets 94 upon the tops of the mold side sections. The lower ends of the lateral latch bars 90 are provided with outwardly projecting pins which extend into suitable terminal slots in the levers 95 (Fig. 9) the opposite ends of which are fixed to the shafts 96 pivotally mounted in the bearings 97 upon the stationary side walls of the bottom section 75 of the mold. The shafts are provided with bottom latches 98 which hook upon the pins 99-carried in the ears 100 projecting downwardly from the side sections.

It will be readily understood that by moving upwardly the top latch rods 91 as by means of the cross-bar 101 secured thereto and the pulley or ratchet lift chain 102 secured to said bar, the top latches 92 will be lifted so as to become unhooked from the pins 93, and the lateral latch bars 90 will also move upwardly and with them the lateral latches 89 so as to unhook the latter from the ,pins 88. Moreover the pins on the lower ends of the lateral latch bars 90 will rock the shafts 96 through the intermediary of the levers 95 so as to unhook the bottom latches 98 from the pins 99. The side mold sections are now free so that they can be moved to the open position shown by dotted lines in Fig. 9 by the mechanism now to be described.

At each end of the mold and secured to the stationary end walls 74 thereof horizontally extending tracks 103 strengthened by the braces 104 are provided. Resting upon these tracks are rollers 105 rotatably carried upon pins secured to the blocks 106 secured to the mold side sections; thus the side sections are each capable of being supported by rollers upon the tracks.

At the ends of the mold and supported by the legs 72 are the fluid pressure motors 107 each comprising a cylinder connected by suitable valved connections (not shown) which may be similar to those of the motor 46 of Fig. 1, with a supply of fluid under pressure. The piston rod 108 of each of the motors 107 is connected by links 109 with the bell crank levers 110 pivotally mounted on the shafts 111 mounted in bearings 112 on the frame 72. The upper ends of the bell crank levers 110 are connected by links 113 with the pins of rollers 105.

The chambers of the side sections formed between the walls 82 and 84 are connected with the interior of the bottom section of the mold by the connection shown enlarged in Fig. 12. This connection comprises the floating pipe 114 passing through an aperture formed in the side wall of the bottom mold section and secured thereto by the diaphragm connection 115. This diaphragmv connection comprises a corrugated metallic disk the periphery of which is secured to the interior of said side wall and the central portion of which, apertured for the passage of the floating pipe 114, is secured to said pipe by a leak-proof joint. The portion of said pipe which extends exteriorly of said side wall is guided Within the collar 116 bolted to the outside of said wall and a spring 117 within said collar and between said side wall and the flange 118 on the outer end of said floating pipe tends to thrust said pipe outwardly and to maintain a close connection between the conical valve face on the extremity of said pipe and the cooperating valve face on the inner end of the angle or elbow pipe 119 the outer vertical end of which is connected by the pipe 120 with the interior of said side section chamber. Straddling the collar 116 and pivoted thereto is the U-shaped securing member 121 provided with a cam 122 pivoted thereto and equipped with a handle 123. It is obvious that to release the securing member it is only necessary to turn down the handle 123, whereby the cam 122 becomes free of the angle pipe 119 and then move the thus freed securing member 121 downwardly to the position shown dotted in Fig. 12.

It will be seen that when the side sections have been unlatched and the pipe connection freed as explained above, and fluid under pressure is admitted to the motors 107, the bell crank levers 110 will be moved to the dotted position of Fig. 9 and the side sections will move laterally, these rollers 105 rolling upon the tracks 103 and the pipe connection elements 119 and 120 withdrawing from, the floating pipe 114 until they have assumed the open position shown by the dotted lines in said figure.

The process of my' invention, generally speaking, comprises admitting pulp-liquor 1nto a mold chamber from below so as to fill the chamber, maintaining it in drainage contact with the perforated mold walls until a sufiicient quantity of pulp has deposited thereon, and then removing the remaining pulp-liquor, and, without diminution of pressure to any considerable extent admitting drying fluid under pressure. (When I speak of pulpdiquor I refer to pulp suspended and freely floating in water or other fluid, having added thereto, if desired, cement, sizing material and other substances.) Preferably the amount of water should be suflicient to allow each pulp particle to float separately, or freely, until all the particles are finally deposited in the mold.

By introducing the pulp-liquor through an openlng in or near the bottom of the mold instead of through an opening in or near the top of the mold I obtain a number of marked advantages. Any foreign matter, such as dirt and rust specks, contained in the pulp-liquor, need not be deposited in the forming article, but has the opportunity of settling before the liquor reaches the mold, or of settling while the liquor is in the mold, and of dropping out of the opening. By thus making the article in process of formation the head of the operating column of pulp-liquor, instead of the foot, I also prevent microscopic fragments of pulp, which are present in the pulp-liquor, and have very little, if any, structural value, from depositing at all, as they are kept afloat by the agitation of the liquid, and are withdrawn with the liquid when the pressure medium is admitted to the mold by means of the by-pass. I can quickly empty the mold of pulp-liquor, and introduce my drying medium immediately, thus securing a uniform drying; instead of either awaiting, as heretofore, the drainage of all the pulp-liquor from the mold, or introducing my drying medium before such drainage has been comportions thereof. I can therefore by my new process work with hot pulp-liquor, instead of with cold pulp-liquor as was necessary heretofore, and thus gain the obvious advantage in drying, as there is no longer any danger of a complete drying of one portion of an article before the drying of another portion has been hardly begun (thus causing unevenness and tension) which danger could hitherto be overcome only by using cold pulp-liquor for the purpose of retarding the drying operation.

A further important advantage of the new process is that it is peculiarly adapted for multiple production. Any number of molds of various shapes and capacities may be fed from a common supply tank, each drawing automatically an amount substantially in proportion to the area of its drainage surace.

Thus, feeding from a tank containing pulp-liquor containing 1 grain of pulp per cubic inch, and governed entirely by the time of flow allowed, I have operated simultaneously a 3 gallon can mold12 inches high having 561 square inches drainage surface; and a 16 gallon barrel mold 22 inches high, having 1350 square inches drainage surface; the extent of the two drainage surfaces being in the approximate proportion of 1 to 2.4.

In seconds the can mold had a deposit of 11,771 grains, while the barrel mold had a deposit of 28,572 grains.

In seconds the can mold had a deposit of 12,427 grains, while the barrel mold had a deposit of 29,445 grains.

In each case the proportion between the deposit on the can mold and the deposit on the barrel was approximately the same as the proportion between the drainage sur faces of the respective molds. Thus 11171 2.4=28250, as compared with 28572 actually deposited; and 12427 2A=28824 as pompared with 29445 actually deposited. At the desired moment the drying fluid may be admitted to each simultaneously whereby the filling and drying of a number of molds of different heights may be accomplished as a single operation. It is obvious that such a process is not practical when the molds are fed from above, in accordance with the prior processes, because the whole contents of every mold would have to be deposited before drying could be completed, thus producing irregularities in drying and uneven thicknesses of deposit for the various articles.

A special advantage of the present proc ess in connection with hollow articles is that all structural weaknesses are eliminated such as pitting caused by the dripping of drying fluid condensed within the measuring chamber above the mold chamber and falling'upon the interior bottom of the article.

In carrying out my process with the aid of" the hollow article apparatus illustrated, a charge of suitable pulp, suspended preferably in water, is first admitted through the pulp inlet 16 into the container 13 and kept in homogeneous condition by the operation of the agitator 14. When it is deslred to flow pulp from this container into the mold shown or a plurality of molds of that or any other type the valve 18 is opened and the pulp-liquor allowed to flow by gravity through the molding mechanism inlet pipes 19. This flow may be aided by admittlng air pressure into the top portion of the container through the air pressure pipe 36, the valves at the lower ends of the air pressure pipe 36 and the superheated steam pipe 37,

eing of course, closed. The p'ulpl1quor is thus caused to enter and flow upward in the pipe section 30, (the valve 31 being open and the valve 32 in the discharge pipe 31 being closed) and then to enter the chamber 25 from which it rises through the mold entrance pipe 33 and fills the mold cavity. Baille 34 revents spurting or splashing. The pulp-liquor immediately starts to drain through the fabric 38 and perforated metal sheet 39 and after passing through the spaces between the ribs 40 escapes through the liquor drainage pipes 41 and 43.

After the article A has formed in this way to a desired thickness the valve 18 is closed and the drainage pipe valve 32 opened and simultaneously the drying medium valve is opened to admit such fluid under pressure into the mold through the pipe 35, chamber 25 and mold entrance pipe 33. Thus the drying fluid is admitted without sufficient loss of pressure in the mold to affect the structural density of the article A.

I prefer to admit, as such drying fluid, first compressed air by opening the valve in the lower end of pipe 36 and then closing said valve and at the same time opening the valve in the lower end of pipe 37, admitting superheated steam as the final drying agent. In this way there is no loss of the drying heat of the steam due to condensation upon meeting with the pulp-liquor still unclischarged from the mold, the pipe 33 and the chamber 25. Of course, steam or superheated steam may be used alone, but preferably air is first admitted, as explained, and caused to act until all of the pulp-liquor has been drained, at which point of time the slidevalve 32 is closed.

\Vhen the article A has become sufficiently dried by the superheated steam, which causes the evaporation of interstitial water and the removal of such water through the draina i es 41 and 43, the dr 'ng fluid pipe vgl v is closed and the mold is read to open. This operation is accomplishe by pulling down the chain 71 to release the clutch elements 65 and opening the valve 51 to admit fluid under pressure to the motor 46, resulting in the separation of the mold sections, as hereinbefore explained, to the position shown in Fig. 5. By unlatchmg the element 45 the central mold section may 1tself be swung open, as will be readily understood, to the position shown in Fig. 2 and the finished article A can easily be removed. The mold is then closed for a second forming operation in the manner previously described, the clutch elements 65 acting automatically to maintain the sections in closed position.

In the operation of the modified molding device for the production of flat pulp boards the ulp is caused to flow into the inlet pipe 19 Fig. 10) in the manner previously described. From this pipe it enters the bottom mold section through the pipe 7 6, the valve 77 being open and the valve 79 in the discharge pipe 78 being closed, and encounters the splash-preventing baflles 80, passing by which it enters and fills the mold cavity and begins to deposit upon the reticulated walls 81, the ulp-liquor draining through them and disc arging through the pipe 83. When a sufiicient deposit has formed, drying fluid is introduced through the by-pass p pe in the manner described for the hollow arti- 'cle molding apparatus, the valve 18 being closed, as before,and the drainage pipe valve 7 9 being opened and later closed as described for the corresponding valve 32.

When the drying operation is completed,

the drying fluid pipe is closed and the device is ready for opening to remove the formed boards adhering to the walls 81. This opening operation is accomplished by pulling upwardly the lift chain 102 to unhook the top latches 92, the lateral latches 89 and the bottom latches 98 from their associated pins secured to the mold sections, in the manner already described, and then admitting fluid under pressure into the motors 107. The piston rods 108 of these motors are thus caused to move upwardly to produce a rotation, through the connecting links 109, of the bell crank levers 110 upon their pivots 111, the upper ends of said levers 110 operating through the links 113 to move laterally the pins of the rollers 105 and the mold side sections secured to said pins, In such lateral movement the bottom portions of the side sections are swung outwardly from the stationary parts of the device, the securing members 121 being of course first released by operating the handle 123 as above described, the top portions are swung downwardly and the central sections move horizontally outward being carried by their 1,se7,ooo I rollers 105 which run upon the tracks 103. The outermost, or open, position of these side sections is shown by dotted lines in Fig. 9. In this position the pulp boards may be re moved in any convement way. It is obvious that to return these sections to closed position, the fluid may be drained from the motors 107 and the side sections swung back into place, and the securing members 121 locked by hand, after which the several latches may be hooked to the appropriate pintles thereon by lowering the pull chain 102.

Both the hollow article mold and the flat board mold illustrated have been described as being constructed with differential pressure mechanism whereby the greater the pressure in the mold the greater will be the tightness of its joints. The operation of this special construction is as follows: In the case of the hollow article mold the lower section 23 thereof normally rests upon the studs 21 but is capable of moving upwardly slightly to the limiting position in which the annular flange 23 comes against the under side of the table 26. When the mold is in closed position, the bottom section is supported upon the studs 24. As soon as pressure fluid is admitted there is a tendency for such fluid to leak out through the horizontal joints between the central mold section and the top and bottom mold sections; but there is a greater tendency for the bottom section to move upwardly against the central section and both of said sections to move upwardly against the immovable top section so as to close these joints against leakage, this movement tendency being due to the fact that the area of the bottom section exposed to the interior of the chamber 25 is greater than the area of either the top or bottom sections exposed to the interior of the mold. The result is that leakage is practically impossible; and the rabbeted fitting of the various mold sections, furthermore, holds the cent ral section from swinging open even though it be not provided with the latch mechanism 4-5.

In the flat board mold one of the side sections forms a rabbeted joint with a floating frame 86 (Fig. 11) movable slightly laterally on account of its flexible connection 87 with the stationary walls of the mold cavity. Any tendency of the pressure fluid to tree this joint and allow leakage therethrough is overcome by a greater tendency to tighten the joint, this advantageous result being due to the fact that the area of the floating frame 86 and its flexible connection 87 exposed to the pressure medium is greater than so much of the area of the other side of the frame as is exposed to the pressure medium. Whatever the pressure, therefore, the joint is maintained closed. The opposite side section is positively latched to the first mentioned section, and its rabbeted joint with I claim:

the fixed frame 85 cannot leak because, while the area against which pressure acts to cause leakage is the area of the side section bounded by the inner edge of said frame 85, the area against which pressure acts to prevent leakage, acting upon this side section through the intermediary of the latches 89, 92 and 98, is the larger area composed of the area of the first section bounded by the floating frame 86 added to the area of the floating frame and its flexible connection 87 exposed to the interior of the mold. It is thus practically impossible for any of the joints to leak.

Differential pressure connections are also provided, between the pipes 120 and the side Walls of the bottom section 75 of the flat board machine. The spring 117 normally holds the floating pipe 114 outwardly against the elbow 119. Pressure within these pipes tending to break this joint by moving floating pipes inwardly against such spring pressure has only the area of the float ing pipe at this joint to act against and this is overcome, as will readily be seen, by the pressure within the bottom section of the -mold acting against the greater area of the flexible diaphragm 115 to force the floating pipe outwardly and maintain the joint un broken. 7

Another important constructional feature of the flat board machine is that which admits the same pressure fluid which is admitted to the mold cavity to the chamber in each side section between the walls 82 and 84 thereof. The pressure on one side of the wall 82 is therefore exactly counterbalanced by the pressure on the other side of said wall. There is thus no chance for the huekling of said wall and no necessity for massive bracing or other heavy constructions for the purpose of making the mold walls strong enough to withstand the fluid pressure introduced into the mold. When pulp is admitted into the mold cavity through the pipe 76 it is also free to flow through the pipes 114, 119 and 120 into" the cavities behind the perforated walls of the mold; and when the pulp is withdrawn from the mold cavity through the discharge pipe 78 the pulp in these side cavities is also withdrawn; and

-'when drying fluidis introduced through the pipe 35 into the mold it also enters into these side cavities. Even though air or pulp or other fluid may be trapped within these side cavities when other fluid is admitted to the balancing effect is a matter of pressure and not of pressure medium;

1. The process of molding pulp articles which comprises depositing pulp upon the reticulated wall of a mold until sufficient deposit has been made, by introducing pulp liquor under pressure into a mold having such wall and removing the water which has 3. The process of molding pulp articles I which comprises depositing pulp upon the reticulated wall of a mold until sufiicient deposit has been made, by introducing pulpliquor under pressure into a mold having such wall and removing the water which has passed through said wall, removing the undeposited pulp and its liquor substantiall without permitting further deposit, simu taneously therewith introducing air under pressure until all the pulp liquor has been removed and then introducing superheated steam under pressure.

4. The process of molding pulp articles which comprises introducing pulp-liquor upwardly into a mold having a reticulated Wall until a suflicient pulp deposit has formed upon said wall, and then suddenly discharging the undeposited pulp and its liquor through said opening.

5. The process of molding pulp articles which comprises introducing pulp-liquor upwardly into a mold having a reticulated wall until a sufficient pulp deposit has formed upon said wall, then suddenly discharging the undeposited pulp and its liquor through said opening and simultaneously therewith introducing drying fluid into the mold, whereby pressure upon the deposited pulp is maintained.

6. -The process of molding pul articles which comprises introducing pulpiquor upwardly into a mold having a reticulated wall until a sufficient pulp de osit has formed upon said wall, then, sud enly discharging the undeposited ulp and, its liquor through said opening an slmultaneously therewith mold, and thereafter introducing super-- heated steam under pressure. mold, the result will be the same because the .7. The process of molding pulp articles which comprises introducing pulp-liquor under pressure upwardly into a mold having a reticulatedwall until a sufiicient-pulp deposit has formed upon said wall,,whereb v introducing air under pressure. into the an upward current is produced during deposition preventing the settling ofthe heavier particles of said pulp-liquornpon the mold bottom and causing whatever of such heavy partidles are deposited to be distributed throughout the area of deposition, and then suddenly discharging the undeposited pulp and its liquor downwardly through an opening in said mold bottom.

8. The process of molding pulp articles which comprises introducing pulp-liquor under pressure upwardly into a mold having a reticulated wall until a suflicient pulp deposit has formed on said wall, whereby an upward current is produced during deposition preventing the settling of the heavier particles of said pulp-liquor upon the mold bottom and causing whatever of such heavy particles are deposited to be distributed throughout the area of deposition, then suddenly discharging the undeposited pulp and its liquor downwardly through an opening in said mold bottom and. simultaneously therewith introducing drying fluid under pressure into'the mold.

9. The process of molding pulp articles which comprises introducing pulp-liquor under pressure upwardly into a mold having a reticulated wall until a suflicient pulp deposit has formed on said wall, whereby an upward current is produced during deposition preventing the settling of the heavier particles of said pulp-liquor upon the mold bottom and causing whatever of such heavy particles are deposited to be [distributed throughout the area of deposition, then suddenly discharging the undeposited pulp and its liquor downwardly through an opening in said mold bottom, simultaneously introducing air under pressure into the mold until all the said undeposited ulp and its liquor has been discharged and then introducing superheated steam under pressure into the mold.

10. An apparatus for molding pulp articles, comprising a pulp-liquor container, a mold having a reticulated wall, a valved connection between said container and the bottom portion of said mold forconducting pulp-liquor from said container to said mold, a valved drainage pipe leading from the bottom portion of said mold and a drying fluid pipe leading into said mold.

11. An apparatus for molding pulp articles, comprising a pulp-liquor container, a mold having a reticulated wall, avalved connection between said container and the bottom portion of said mold for conductin pulp-liquor from said container to sai mold, a valved drainage pipe leading from the bottom portion of said mold and a drying fluid pipe leading into said connection at a point below said mold.

12. An apparatus for molding pulp articles, comprising a mold having a reticulated wall, and an opening in the bottom thereof, controlled means for introducing pulp-liquor into said mold through said opening and controlled means for draining said mold through said opening.

13. An apparatus for molding pulp articles, comprising a mold having a reticulated wall, and an openin in the bottom thereof, controlled means for introducing pulpliquor into said mold, said opening, convided with a reticulated wall, a chamber below said mold, a connection between said mold and said chamber, a valved connection between said container and said chamber, a valved drainage pipe from said chamber and a valved drying fluid pipe leading into said chamber.

16. An apparatus for molding hollow pulp articles, comprising a mold having a separable top, bottom and side sections, said sections being provided with reticulated walls and said bottom section being provided with an opening, controlled means for introducing pulp-liquor into said mold through said opening and controlled means for draining said mold through said openm %7. An apparatus for molding hollow pulp articles, comprising a mold having separable top, bottom and side sections, said sections being provided with reticulated walls and said bottom section being provided with an opening, controlled means for introducing pulp-liquor into said mold through said opening, controlled means for draining said mold through said opening and controlled means for introducing a drying fluid into said mold.

13. An apparatus for molding hollow pulp articles, comprising a mold having separable top, bottom and side sections, said sections being provided with reticulated walls, a motor, a lever system connecting said motor with said top section for separating said top section from said side section, and a connection between said lever system and saidside section and operative to separate said side section from said bottom section after said top section has been separated from said side section.

In testimony whereof I have hereunto set my hand.

JULIAN H. RIVERS.

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