US3067815A - Suspension distributing system - Google Patents

Description

Dec. 11, 1962 H. FLAIG ET AL SUSPENSION DISTRIBUTING SYSTEM 2 Sheets- Sheet 1 Filed May 4, 1959 INVENTORS HEINRICH FLA/G ADOLF STARK C\ Mum, 55/9 Al/amays I Dec.'ll, 1962 H. FLAIG ETAL 3,067,815

SUSPENSION DISTRIBUTING SYSTEM Filed May 4, 1959 2 Sheets-Sheet 2 INVENTORS HEl/VR/CH FLA/6 ADOLF $734RK United States Patent 3,057,815 SUSPENSIGN DHSTRIBUTIYG SYSTEM Heinrich Fiaig and Adolf Stark, Heidenheim, Germany, assignors to J. M. Voith G.m.b.H., Maschinenfabrik, Heidenheim (Brena), Germany Filed May 4, 1959, Ser. No. 810,618 Claims priority, appiication Germany May 9, 1958 12 Claims. (Cl. 162342) This invention relates to a distributing system for suspensions and more particularly to suspension inlets for dehydrating machines and stock inlets for paper-making machines.

it thus relates to distributing systems for such machines which are to effect a perfectly even distribution of a fibrous suspension supplied through a feed pipe over the entire width of a band or, for instance, a Fourdrinier wire in a paper-making machine, the width of which band is much larger than the diameter of the aforesaid feed pipe. Furthermore, the distribution must be effected in such a manner that the formation of deposits of the suspended matter and the occlusion of air in the feeding and distributing devices is practically eliminated.

The known devices generally comprise a feeding line or pipe means, a distributor for the stock or other suspension, and a headbox from which the suspension is discharged as a wide band.

In paper-making and similar machines, the fibrous suspension or stock is generally conveyed from a machine chest via a stock regulator, refining devices and purifying devices such as screeners, hydrocyclones or the like, and finally through the above-mentioned feed pipe to the wire of the paper making machine. This involves the problem of converting the flow of stock through the feed pipe of, in most cases, circular cross-sectional area, to a stream of rectangular cross-sectional area corresponding in width to that of the machine wire. Moreover, this conversion must be effected in such a manner that the quantity and velocity of the stock leaving the rectangular, mostly slot-shaped discharge gate of the headboX must be completely uniform over the entire width of the machine wire, as the fiber web to be produced on the wire is to be of even thickness and weight over that entire wire width.

A known device for achieving a uniform flow in the headbox of a stock inlet for paper making machines is described in Patent 2,677,991 (German Patent 808,081), and comprises a wide closed pond chamber, a deceleration section extending upwardly toward the chamber, and a wide downwardly extending acceleration section. The stock is delivered first to a distributor box and from there to a slot-shaped entrance of the aforesaid deceleration section of the headbox. In the latter section which is devised as a diffuser with upwardly diverging walls, the stock velocity of flow is decreased and a distribution and direction of the flowing stock is attained by providing several perforated rolls across that section. The decelera- I tion diffusor-type section opens with its larger, upper end into the aforesaid pond chamber the upper part of which encloses an air cushion. From this pond the stock flows downwardly into a long, narrow accelerating section from which it emerges by Way of a slot-shaped gate on to the machine wire. This known device requires very large dimensions in order to attain the desired effects of sufficient deceleration and acceleration, and constructions 30 feet high have been built in practice.

Therefore, another known device has the object of attaining a uniform flow of stock already in the stock distributor preceding the headbox and thereby obtaining a much more compact stock inlet device of greatly reduced dimensions compared with that of Patent 2,677,991 more recent device, which is described in German Patent 3,067,815 Patented Dec. 11, 1962 1 851,301, assigned to the same assignee as the present application. This device comprises a stock distributor having one or several primary distributing chambers which are connected by way of one or several conduit means to a secondary common distributing chamber arranged, in the direction of stock flow, subsequent to the aforesaid primary distributing chamber or chambers. Communication between the primary distributing chamber or chambers and the secondary chamber is effected through a slot-shaped gate arranged at the central region of the primary distributing chamber or chambers. However, this has the drawback that the suspension enters the secondary chamber in the form of a jet which is only relatively incompletely disintegrated in space owing to the short distance available for such spatial disintegration in the secondary distributing chamber. Therefore, the distribution of stock flow in this secondary chamber does not take place with a completely satisfactory degree of uniformity, Wherefore a further additional device for uni form distribution of the stock in the headbox is indispensable. Moreover, the connection of the aforesaid conduit means to the central region of the primary chamber suflers from the drawback that air cushions may form in the upper portion of this chamber and lead to the formation of fiber lumps or deposits.

It is, therefore, the object of our invention to provide a distributing device of the type comprising several successively arranged distributing chambers for connection to and preceding a headboX or the like discharge means for suspensions such as, in particular, fibrous suspensions or stock, in the direction of flow of the suspension, which distributing device avoids the above-described drawbacks and permits to attain a satisfactorily uniform distribution of the suspension over the entire width of the band onto which it is to be discharged and to establish the conditions of flow required at such discharge, already in the distributing device prior to the entrance of the sus pension into the headbox or a corresponding discharging device.

The term dehydrating machine where used in this specification and the appended claims includes papermaking machines and the like.

The term suspension as used in this specification includes all non-colloidal two phase systems comprising a solid and a liquid phase, and more particular suspensions in which the liquid phase is water and the solid phase is a fibrous material.

This object is attained by the suspension distributing device according to our invention which comprises, interposed in the path of flow of the suspension through a supply line of substantially circular or similar cross section to a headbox for the discharge of the suspension in a transversely widened band, two successively arranged distributing means, of which the first means is in communication with the aforesaid supply line and comprises at least one, or several, primary distributing chambers, communicating all to a common, subsequently arranged secondary distributing chamber, and characterized in that the communication between the primary distributing chamber or chambers and the secondary common distributing chamber is effected by way of an opening disposed in the uppermost zone of the primary chamber or chambers and a diffusor-type section, two opposite ones of the walls of which diverge from said opening in the primary distributing chamber to merge at its widest cross section into the secondary chamber.

parallel to the secondary chamber, offers the advantages of creating favorable conditions of flow in the suspension passing therethrough and of causing a continuous removal of the air entrained in the suspension, thereby avoiding the formation of air cushions leading to undesirable deposits of solid matter in the apparatus.

If the suspension to be distributed is fibrous suspension such as paper stock, the dilfusor section merging with the secondary distributing chamber can be relatively short and have the two opposite diverging walls open by an angle of at least 8 and preferably about 30, and is provided with one or several auxiliary distributing members arranged in the path of stock flow.

The secondary distributing chamber has a length, in a direction transverse to that of the movement of the suspension therethrough, which length is about equal to the width of the suspension band to be formed, for instance, on a Fourdrinier wire.

These features in the diffusor section in the distributing device according to the invention achieve that the suspension jet emerging from the primary distributing chamber gradually spreads in the diffuser section and that the suspension is so strongly decelerated that its velocity is almost equal to zero in the second distributing chamber, which latter velocity would have to be attained in order to achieve an ideal equalization of pressures and velocities in the suspension.

This equalization of the flow velocities in the interior of the diffusor is essentially facilitated by the abovementioned arrangement of auxiliary members; furthermore these members prevent the creation of non-laminar fiow which would involve a separation of the boundary layer of fluid from the diffusor walls.

Tests carried out in practice have confirmed that the various features of the distributing device according to the invention make it possible to attain an almost ideally uniform distribution of pressure and velocity over the entire width of the slot-shaped outlet opening of the secondary distributing chamber, by way of which opening the distributing device is, for instance, connected to the headbox of a paper-making machine.

It is, therefore, not necessary to arrange further auxiliary distributing members in the headbox, so that the dimensions of the latter can be held considerably smaller than in the known stock inlet systems. Of course, one or several rotary defloccing members may nevertheless be provided to prevent flocculation of the stock in the headbox.

The auxiliary distributing members arranged in the diifusor section of the secondary distributing chamber may be perforated rolls as described in Patent 2,677,991; baflie rolls or rectifier rolls of the type described in Patent 2,699,096; cage type rolls as described in Patent 2,737,- 087 and, in fact, any other suitable known type of rolls. These rolls can be arranged in different manners in the interior of the diffusor as will be explained further below.

Generally, the use of a single perforated roll in the diffuser section connected to the primary distributing chamber leads to a radially spreading expansion of the flow of the stock. In order to avoid the uneven distribution of flow velocities causing this phenomenon, a plurality of rolls either in series, or in a parallel arrangement, is provided with the axes of the rolls located on an arc, the center of which is located in the direction toward the entrance from which the stock flows into the diffuser section.

Certain suspensions such as in particular suspensions of textile fibers do not permit the use of auxiliary distributing members in the diffuser. In this case, the diverging walls of the distributor section of the secondary chamber in the distributing system according to our invention should diverge by an angle from about 3 to maximally 8. Hence, the diffuser section is built correspondingly longer. No auxiliary distributing members i will then be provided in the interior of the diffusor sectlon.

The longer construction of the diffuser section for dis tributing this type of fibrous suspensions is warranted by the almost ideal equalization of pressure and velocities over the entire width of the suspension band leaving the secondary distributing chamber. The velocity equalization achieved in this arrangement is much better than if the conduit between the primary and secondary distributing chambers were only a slot-shaped opening.

In order to obtain a favorable transitional flow from the primary chamber, or chambers to the diffusor section of the secondary chamber, it is preferred to provide a short-shaped conduit of substantially constant, preferably rectangular cross sectional area between outlet opening of the primary chamber and the entrance to the diifusor section.

The invention will be further explained in detail hereinafter in connection with the accompanying drawings in which FIGURE 1 shows in perspective and partly sectional view a suspension distributing system equipped with an embodiment of the distributing device according to the invention, and which is particularly adapted as a stock inlet for paper-making machines;

FIGURE 2 is a schematical view of a difierent embodiment of the distributing device according to the invention;

FIGURE 3 shows schematically a further embodiment of the distributing device according to the invention, comprising two primary distributing chambers and a common secondary distributing chamber;

FIGURE 4 shows schematically yet another embodiment of the distributing device similar to that shown in FIGURE 3; and

FIGURE 5 is a sectional view of another suspension distributing device according to the invention, which device is particularly suited for discharging a wide band of a suspension of textile fibers, which do not permit the use of auxiliary distributing means such as perforated rolls and the like.

Referring now to the drawings more in detail, the suspension distributing system illustrated in FIGURE 1 and suitable as a stock inlet for a paper-making machine equipped with a Fourdrinier wire 1 which system comprises interposed between a stock feed pipe 2 of, for instance, circular cross section, and a headbox 4 according to the invention an embodiment of the suspension distributing device.

This entire distributing device is designated by reference numeral 3, and comprises a single primary distributing chamber 5 the cross sectional area of which approximates a circular area, so that the entire chamber 5 is of approximately tubular configuration, a slot-like opening 5a in the cylinder wall merging into a short passageway 6 of substantially constant rectangular cross sectional area, which opening 5a opens in the uppermost zone 5b of chamber 5, a flow decelerating diffusor section 7 connected with its narrower opening to the passageway 6 so as to be in communication, through the latter, with the aforesaid primary chamber 5. The decelerating diffuser section 7 has divergent opposite walls 26 and 27, being the top and bottom walls, respectively, while the sidevalls of the diffusor section 7 one of which is shown at 22 may be either parallel with each other or divergent from the narrowest, rectangular cross sectional area at the opening of passageway 6.

In the embodiments shown in FIGURES l and 2, the diffuser section 7 is devised with a divergent angle of approximately 30. In the interior of this section and behind the entrance thereto from passageway 6, there is provided a perforated roll It as an auxiliary rotary distributing member, so as to further improve the evening out of the how conditions of the suspension. Roll 10 has a ratio of perforations to entire cylindrical surface of about 25 to 30%.

The high opening angle of about 30 of the diliusor section '7 in combination with the provision of roll ltl permits to build the diffusor section 7 relatively short.

The diffuser section '7 merges into a secondary distributing chamber 8, walls 26 and 27- of the former being continued by the approximately semicircular end wall 23 of the latter chamber 8.

This secondary distributing chamber 3 is provided with a slot-shaped outlet '9 extending over substantially the entire width of the secondary chamber 3 in the uppermost zone 8a of that chamber. To the outlet of chamber 8 there is connected the stock entrance of headbox 4 which is devised preferably as a short decelerating section 12, with divergent side walls 12a and 11212, the latter of which is slightly inclined out of the vertical plane, so that this section has an axis slightly inclined from the vertical.

Headbox 4 is further provided with a conventional slot-shaped stock discharge nozzle 13 from which the stock is transferred on to wire 1; inside the headbox 4 and in front of nozzle 13 there is provided another rotary member in the form of a perforated roll 14.

This roll 14 has a much larger ratio of open surface to total surface than roll 10, namely, about 55%. This roll serves primarily to prevent flocculation of the suspension and less to perfect distribution conditions, since the stock or other suspension arrives already perfectly well evened from outlet h.

In FIGURES 2 3, and 4, the headbox 4 has been omitted to simplify the drawings. Feed pipe 2 has been shown schematically as connected by flange means to the primary chamber 5 or to the primary chambers 16, 17 or 16a, 17a in FIGURES 3 and 4. It will be noted that, while pipe 2 opens into the cylindrical wall of chamber 5, similar to the arrangement shown in FIGURE 1, the feed pipes 2 in FIGURES 3 and 4 are connected to the end walls 22 of chambers 5 as indicated in phantom lines at 2 in FIGURE 1.

The embodiment shown in FIGURE 2 diliers from that of FIGURE 1 in that the diffuser section 7a extends upwardly instead of horizontally away from passageway d, as is the case in FIGURE 1. Passageway 6 in this embodiment is very short.

Apart from perforated roll lit, a second rotary distributing member, for instance, a rectifying roll 15 of larger diameter than roll it), is arranged in series subsequent to roll It} in the interior of diiiusor section 7a.

In the embodiment shown in FIGURE 3, the distributing system according to the invention comprises two primary distributing chambers In and I7 and connected thereto, in a manner similar to that described in connection with FIGURE 1, diliusor section 7b associated with chamber lid, and diffusor section 7c associated with chamber 17. The chambers 16 and 17 are of square cross section in this embodiment. Both ditlusor sections 712 and 7c merge into the common secondary distributor chamber 18 at the uppermost zone of which there is provided outlet 19, to which a headbox or the like can be connected.

A plurality of auxiliary distributing members in the form of perforated rolls lid-:2 is mounted in the interior of diffusers 7b and '70. Each of the groups of members comprises five, two aligned in a first row across the distributor section and immediately in front of passageway 6, and three more aligned with each other in a second row behind and in staggered relation to the first row of rolls.

In the embodiment of the invention shown in FIG- URE 4, the distributing system also comprises two primary distributing chambers 16:: and 17a adjacent each other, each with a longer passageway 6b, 60 opening into a dififusor section 7d, 7e, respectively. The two diilusor sections 7d and 7e which merge into the common secondary chamber 18a, are arranged with their axes of how parallel to each other, while these axes form an angle ,8 of about with each other in the embodiment shown in FIGURE 3.

In the interior of clifiusors 7d and 7e, groups of three perforated distributing rolls 10b are arranged with their axes on arcs the centers of which are located on the side of the passageways 6b, 6c. A headbox may be connected in the same manner as illustrated in FIGURE 1, to the outlet 19 of secondary distributing chamber 18a.

lFinally, if suspensions of textile and the ike ctibers are to be distributed, the fibrous material which does not permit of the use of auxiliary distributing rolls, an embodiment of the distributing system according to the invention of the kind illustrated in FIGURE 5, can be used. This distributing system is similar to that illustrated in FIGURE 1, with the difference that the diffusor section 37 connected to a short passageway 36 from primary chamber 5, is greatly elongated and that the walls 38 and 39 diverge by a much smaller angle 06' than the walls 26 and 27 in the embodiment of FIGURE 1. The divergence angle or in the embodiment of FIGURE 5 ranges from about 3 to 8 only. The ratio of ditfusor length L to the diameter D of the secondary distributing chamber is about 9:1 in the embodiment shown in FIGURE 5, while it is about 2:1 in the embodiment shown in FIG- URE 1, and about 3:2 in the embodiment shown in FIG- URE 2. In the embodiment shown in FIGURE 5 that ratio may conveniently vary from about 5:1 to 10:1 and higher depending on the exact nature of the suspension.

It will be understood that these ratios are given by way of example only, while the ratio L:D can be varied within considerably wider limits. Also the number of distributing chambers can be greater than two, for instance, three, four, or five etc. Furthermore, the pas sageway between the primary distributing chamber and the difi'usor section may be subdivided to form several communicating paths between the two spaces, or several passageways from one and the same primary chamber may communicate each with one dillusor section, all diffuser sections then merging into one and the same secondary distributing chamber.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

We claim:

1. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one difiusor section merged therewith, said diflusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber, said diffusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

2. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one ditfusor section merged therewith, said diffuser section having an entrance opening and two opposite walls extending over the Whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30, said dii'fusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamher, and further comprising at least one rotary auxiliary distributing member in said ditfusor section, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

3. A distributing system as described in claim 2, wherein said rotary auxiliary distributing member is a rectifier roll of known constructon.

4. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating ma chine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one diffusor section merged therewith, said difiusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30", said diifusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, and further comprising at least one perforated roll of known construction as a rotary auxiliary distributing member in said diffusor section, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

5. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slitshaped opening in the uppermost part thereof; a secondary distributing chamber having one diffuser section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30, said ditiusor section being connected by way of said entrance opening and a short conduit of substantially constant cross sectional area to said outlet opening in said primary distributing chamber, and further comprising at least one rotary auxiliary distributing member in said ditfusor section, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

6. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one ditfusor section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamher by an angle of at least 8 up to approximately 30, further comprising a plurality of rotary auxiliary distributing members disposed in the interior of said diiiusor section in series and with increasing diameters in the direction of suspension flow through said diffusor section, said diffusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

7. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the sys= tem and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are con nected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one diiiusor section merged therewith, said ditfusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distribution chamber by an angle of at least 8 up to approximately 30, further com prising a plurality of rotary auxiliary distributing mem bers disposed in said ditfusor section in alignment transversely to the direction of suspension flow through said difiusor section, said dittusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

8. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one diffuser section merged therewith, said diifusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30, further comprising a plurality of rotary auxiliary distributing members disposed in the interior of said diffusor section in series and with their axes located on an arc the center of which is disposed toward said ditfusor section entrance, said diifusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said head box thereto.

9. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one difiusor section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30, further comprising a plurality of rotary auxiliary distributing members disposed in said diffuser section in several groups, the members of each group being in alignment with each other transversely to the direction of suspension flow through said diffuser section, said groups being disposed one behind the other in the direction of suspension flow therethrough, said dittusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

10. A distributing system for suspensions of fibrous materials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one diffusor section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least 8 up to approximately 30, further comprising a plurality of rotary auxiliary distributing members disposed in said diifusor section in several groups, the members of each group being in alignment with each other transversely to the direction of suspension flow through said diffusor section, said groups being disposed one behind the other in the direction of suspension flow therethrough, the members of one of said groups being staggered with regard to the members of the group preceding said one group in the direction of suspension flow, said difiusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

11. A distributing system for suspensions of fibrous ma terials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one diffuse-r section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least about 3 and up to about 8, and wherein the interior of said diffusor section is free for unimpeded suspension flow, said diffusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

12. A distributing system for suspensions of fibrous ma- 10 terials to be supplied through feed pipe means to the system and delivered from there to a dehydrating machine, comprising, in combination, a headbox, one primary distributing chamber to which said feed pipe means are connected, said primary distributing chamber having one outlet slit-shaped opening in the uppermost part thereof; a secondary distributing chamber having one difiusor section merged therewith, said diffusor section having an entrance opening and two opposite walls extending over the whole length of the primary and secondary distributing chambers and diverging from said entrance opening towards said secondary distributing chamber by an angle of at least about 3 and up to about 8, wherein the ratio L:D is at least 5 and up to 10 and higher, L being the length of the diitusor section and D the diameter of said secondary distributing chamber at right angle to the diifusor section in a plane parallel to the direction of current flow, and wherein the interior of said difiusor section is free for unimpeded suspension flow, said diflusor section being connected by way of said entrance opening to said outlet opening in said primary distributing chamber, said secondary distributing chamber having an outlet in the highest part for connection of said headbox thereto.

References Cited in the file of this patent UNITED STATES iATENTS 2,347,130 Seaborne Apr. 18, 1944 2,381,286 Hornbostel et al Aug. 7, 1945 2,589,639 Staege Mar. 18, 1952 2,677,991 Goumeniouk May 11, 1954 2,699,096 Hornbostel Jan. 11, 1955 2,737,087 Bennett Mar. 6, 1956 2,747,471 Corbin et a1. May 29, 1956 2,847,913 Cirrito Aug. 19, 1958 2,869,436 Stewart Jan. 20, 1959 2,870,690 Corbin et al Jan. 27, 1959 2,894,581 Goumeniouk July 14, 1959 FOREIGN PATENTS 851,301 Germany Oct. 2, 1952 935,228 Germany Nov. 17, 1955 744,507 Great Britain Feb. 8, 1956 OTHER REFERENCES Mardon et al.: Pulp and Paper Magazine of Canada, October 1954, pp. 107-419.

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