United States Patent 3695448

A device for separating liquid from a slurry having a perforated rotatably driven drum into which the water slurry mixture is introduced and fed along the length thereof for dewatering the slurry and having a brush extending along said drum with bristles engaging said drum for being rotated thereby with the bristles engaging and cleaning the drum perforations of foreign material.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
209/296, 210/403, 210/405
International Classes:
B30B9/12; D21C9/18; (IPC1-7): B01D33/38; B01D33/06
Field of Search:
210/456,433,405,414,403,344,408,377 209
View Patent Images:
US Patent References:
1412010Ore classifier1922-04-04Akins

Foreign References:
Primary Examiner:
Spear Jr., Frank A.
What we claim is

1. A device for separating liquid from a slurry comprising a rotatably supported elongated drum having a side wall with perforations therethrough throughout its length, an inlet opening at one end and an outlet opening at its opposite end, means connected to said drum and capable of rotating said drum around its axis, an interspaced feed screw assembly attached to and positioned along the interior of said drum wall and a rotatably supported cylindrical brush positioned alongside the exterior of said drum wall with its axis extending lengthwise of said drum wall and having bristles extending radially of said brush axis to said drum wall for being rotated therewith whereby said bristles will remove material from said drum wall perforations.

2. A device for separating liquid from a slurry as claimed in claim 1 wherein said interspaced feed screw consists of a plurality of screw flanges extending laterally of and spaced apart along said drum wall providing a plurality of feedless zones therebetween in the interior of said drum.

3. A device for separating liquid from a slurry as claimed in claim 2 wherein each screw flange is a portion of a screw thread and the screw flanges approaching the outlet opening of said drum have an opposite feeding direction to the screw flanges leading from the inlet opening.

4. A device for separating liquid from a slurry as claimed in claim 3 wherein the terminals of each screw flange is located substantially in front of the terminals of adjacent flanges.

5. A device for separating liquid from a slurry as claimed in claim 2 including at least one driving plate provided on said drum wall adjacent at least one screw flange and capable of throwing dewatered pulp back into the zone immediately preceding said screw flange during rotation of said drum. 1

6. A device for separating liquid from a slurry as claimed in claim 1 including a supply tube extending through said drum inlet opening and extending towards the interior of said drum wall for flushing said wall with water fed into said drum with the slurry.

The present invention relates to a device for efficiently separating a liquid from a slurry containing solid or semi-solid particles. Such slurries are used for instance in the paper industry where the paper pulp and certain waste products are conveyed in pipes or ducts in the form of a water slurry. The invention is also applicable in machine tools for separating the cooling liquid from particles such as chips and the like, which are removed from a work piece during machining in order to avoid that such particles otherwise would clog the cooling liquid conduits.

The invention more specifically relates to a separation device which comprises a rotatable elongated drum, the wall of which is provided with perforations and wherein there is provided a feed screw device for feeding in the longitudinal direction of the drum a slurry introduced into the drum at one end thereof and feeding out the dewatered pulp at the opposite end of the drum.

The invention is essentially characterized by the feeding mechanism comprising an interspaced feed screw assembly, the spaces between each screw portion forming a number of feedless zones inside the drum.

In the following an example of a separation device made in accordance with the invention is described with reference to the accompanying drawing in which:

FIG. 1 is a longitudinal cross section through the drum, and

FIG. 2 is a rear end view of the drum as seen from the left in FIG. 1.

The digit 1 indicates a perforated cylindrical wall of a drum the portion of which indicated nearest to the input end on the left of the FIG. I being provided with a number of relatively small perforations, while the portion located nearest to the outlet end is provided with larger perforations as is evident from FIG. 1. The drum is designed to rotate in the direction indicated with the arrow marked in FIG. 2. Said rotation movement is provided by a driving motor 2 (marked in FIG. 2), which by means of a pinion gear 3 engages the toothing of a gear rim provided on one end portion 4 of the drum. The said end portion 4 of the drum is provided with a central opening 5 through which the end portion of a supply feeding tube 6 projects into the interior of the drum. As is evident from FIG. 1 of the drawing the outlet end portion of the feeding tube 6 is bent in a direction towards the wall 1. Mechanisms in the interior of the drum, serving the purpose of feeding the slurry through the drum towards its outlet end, are indicated with 7-13. The combination of said feeding mechanisms form an interspaced screw assembly arranged in the interior of the drum, said assembly exhibiting several interruptions in order to create a number of feedless zones. The feed screw can be designed in a different manner than the one illustrated here, but the design shown has been found to function very efficiently. In the illustrated embodiment the feed screw comprises a number of screw flanges fastened to the inner side of the wall 1 of the drum, of which flanges the ones indicated with 7, 10, 11, 12 and 13 together form one half of one pitch, while the flange 8 describes a complete pitch. The flanges 7, 8 and 10 during the rotation movement of the drum strive to feed the slurry in a direction from the supply tube 6, while the flanges 11 and 13, which exhibit an opposite direction of pitch, tend to feed the slurry in an opposite direction. The digit 9 indicates a driving plate.

The drum is carried by a number of supporting rollers 14. An additional supporting roller 15 is bearing against the end portion 4 of the drum in order to prevent the drum from displacing itself to the left according to FIG. 1. As is evident from FIG. 1 the drum can be given an inclination so that by way of example it will occupy the position indicated by dashed and dotted lines in FIG. 1. Below the drum is a trough 16 for collecting the liquid separated from the slurry and a tube 17 has an orifice in the bottom of the trough in order to discharge said liquid. To prevent the perforations of the walls of the drum from getting clogged, a cylindrical brush 18 is mounted outside the drum, which brush is lying against the wall of the drum and is driven by the same in the direction indicated by an arrow in FIG. 2. By this arrangement the hairs of the brush are caused to penetrate into the perforations and keep them open. Their cleansing action can be further improved by a flushing liquid being introduced into the hub of the brush for example via a rotating coupling. In said arrangement the hub is provided with a number of openings, through which the liquid will be sprayed against the wall of the drum. A protecting plate 19 is designed to take up the liquid, which from the supply tube 6 is splashed out through the perforations of the wall 1 of the drum. In consideration of this splashing action it is convenient that the outlet portion of the supply tube 6 is pointing in a direction towards a place of the wall of the drum being located somewhat lower than the brush 18. Via an inclined ramp 20 the dewatered pulp fed out of the drum is moved down to a conveyor device or similar, not shown.

The dewatering operation in the drum takes place in the following manner. The slurry is pumped into the dewatering drum via the input tube 6 and is thrown against the inner side of the wall of the drum thereby cleansing said wall. The flange 7 is designed to prevent slurry from accumulating near the input end of the drum. Between the flanges 7 and 8 a zone is created, wherein the first dewatering stage is taking place. Because of the relatively small slurry particles comparatively small perforations in the wall of the drum are required in this zone in order to impede such particles from escaping together with the water through said wall. Said first zone being passed, the screw flange 8 acts upon the pulp, feeding the somewhat dewatered slurry forwards. A portion of the pulp thus feed forwards past the screw flange 8 is then brought up along the wall of the drum by the driving plate 9 and thrown back into the first mentioned zone from where it again will be fed forwards by the flange 8. When the mass has arrived in the zone of the drum, where the perforations in the wall are of bigger dimension, it has caked itself into lumps of larger size, which impedes the pulp from escaping through said bigger perforations. During the passage of the pulp between the flanges 10,11, and 12,13 it is subjected to a pressing operation, whereby a comparatively complete dewatering is taking place. Thereafter the dewatered mass is discharged on the ramp 20 from where it slides down for example on a device for its removal transportation.

The invention is not limited to the dewatering device described above and illustrated in the drawing by way of example only, but can be modified as to its details within the scope of the following claims.