FR2530690A1 - DRAINER DEVICE FOR REMOVING WATER FROM A CONTINUOUS SHEET ON A FLAT TABLE MACHINE - Google Patents

Abstract

DRAINING DEVICE FOR ELIMINATING WATER FROM A CONTINUOUS SHEET LOCATED ON A PERFORATED STRIP OF A FLAT TABLE MACHINE, INCLUDING A PERFORATED CYLINDER 28 WHICH TURNS AND IS APPLIED ON THE CONTINUOUS SHEET, AND INCLUDES A FILTERING FABRIC 46 ON ITS PERIPHERY ; THE PERFORATED CYLINDER 28 INCLUDES AN INTERNAL CYLINDER 34 CLOSED ON ITS PERIPHERAL AND SUPPORTING THE FILTERING CLOTH, AS WELL AS, BETWEEN THIS INTERNAL CYLINDER AND THE FILTERING CLOTH 46, AT LEAST ONE CHANNEL WHICH EXTENDS FOLLOWING THE PERIPHERAL DIRECTION AND IS TIGHTLY CLOSED FOLLOWING THE AXIAL DIRECTION WITH RESPECT TO THE FRONT FACES OF THE PERFORATED CYLINDER, TO SUCK WATER FROM THE FILTERING FABRIC 46, THE SUCTION BOX 70 IS ARRANGED AT THE EXTERNAL PERIPHERAL REGION, WHICH TURNS UPWARDS, OF THE PERFORATED CYLINDER 28.

Description

Drainer device for removing water from a continuous sheet on a

machine

at a flat table.

  The invention relates to a draining device for removing water from a continuous sheet lying on a perforated belt of a flat table machine, comprising a perforated cylinder (drip roller) mounted so as to

  be able to turn, and a suction box placed on it

  it to remove water from the continuous sheet up. Especially in the case of the production of papers on which one must be able to write or print on two sides, one cannot remove the water only on one side of the continuous sheet in a paper machine, being

  since then the fine substances in the suspension

  machine brought to the paper machine are drawn essen-

  on one side of the paper strip, and therefore on the other side of the fabricated paper, there is no

  not possible, or very difficult, to write or print

  primer Consequently, we have recently developed formers with two fabrics for which it is essentially a flat table machine against the longitudinal fabric which is supported, from the top,

  an upper filter band, driven by the

  diary of several rollers, in which is arranged a suction box which sucks the water entering the upper filter band. Such a device with upper filter bands makes, however, the removal of water from the continuous sheet on both sides relatively expensive, even if it has a series of advantages such as the possibility of driving the longitudinal fabric with relatively high speeds and

  therefore eliminating water effectively.

  It is also already known to have a suction box in a drip roller, in the form of a perforated cylinder, for sucking the water entering the drip roller from the continuous sheet from which the water must be removed. , when in a flat table machine, the water is removed upwards from the continuous sheet lying on the perforated strip using such a known draining device,

  can only drive the longitudinal fabric with speed

  its relatively low, since the vacuum applied

  inside the drip roller cannot be increased

  arbitrarily, because the sheet

  continuous is lifted from the longitudinal fabric; an increase

  mentation of the speed of rotation of the drip roller going hand in hand with the increase in the speed of the longitudinal fabric, however, leads to greater centrifugal forces acting on the water which enters the drip roller, so that a projection of water does

  can be avoided only by increasing the vacuum

  jection of water drops by the drip roller must this

  during absolutely be avoided since such drops of water otherwise lead to marks on the

continuous sheet.

  In a flat machine at high speed, the pro-

  problem at the base of the invention is to be able to remove the water from the sheet also continues upwards, without this resulting in an expenditure in technical means, such as

  this is necessary in two-canvas trainers mention-

born.

  This problem is solved by means of a draining device comprising a perforated cylinder, in which a filter cloth forms the outer periphery of the perforated cylinder and a suction box is arranged at a level.

  this, thanks to the fact that according to the invention, the cylin-

  dre perforated has an inner cylinder closed on its periphery and supporting the filter fabric, as well as between this inner cylinder and the filter fabric at least one channel which extends in the peripheral direction and is sealed in the axial direction screw -at-

  screws on the front faces of the perforated cylinder, and that

  To draw the water from the filter cloth, the

  rante is located in the peripheral region ex-

  upward side of the perforated cylinder.

  In the case of such a perforated cylinder, the support system

  wearing of the filter cloth provided between the closed inner periphery of the inner cylinder and the filter cloth can be made in a simple manner, for example from strips of

  sheet metal placed on edge joined to each other by the

  through transverse bridges, so that the perforated cylinder can be produced in a cost-advantageous manner The basic idea of the invention is therefore to use the fact that, with the help of a vacuum, the of water

  transmitted to the filter fabric envelope of the per-

  drilled by the continuous sheet is kept in the openings

  tures of the outer filter fabric with extremely fine mesh, against the action of centrifugal forces, until we arrive at the place where the suction box is applied against the outer periphery of the cylinder

  perforated and that this water comes out of the filter cloth

  that the perforated cylinder is provided with an inner cylinder closed on its periphery, and that at least one channel is provided which extends in the peripheral direction of the cylinder

  perforated or several channels which extend at least equally

  in the peripheral direction between the filament fabric

  trant and the inner cylinder, the vacuum applied to these

  through the suction box spreads along a part of the periphery of the perforated cylinder into the region in which the perforated cylinder

  leans on the continuous sheet from which the water must be removed

  mined When using a drainer device according to the invention, due to the sealed closure of the peripheral channels in the axial direction at least vis-à-vis the front faces of the perforated cylinder, there is also only need of a relatively low vacuum, since the suction box can already start immediately above the continuous sheet, so that the water which has penetrated into the perforated cylinder from the continuous sheet is only raised on a weak

  height difference and should not be retained in the cy-

  perforated liner only in a short peripheral region in the direction of rotation of this perforated cylinder, before

  that it be removed from the perforated cylinder via-

re from the suction box.

  In a known draining device (French patent

  çais No 553 198), comprising a complete perforated cylinder-

  open at the level of its front faces and the

  external riphery is formed by a fine filter, a case

  vacuum cleaner is provided above the highest point of the periphery of the perforated cylinder to suck up dirt adhering to the filter, in order to prevent it from causing marks or even holes in the sheet

  continues However, due to the full front faces

  open the perforated cylinder, you cannot create a vacuum in it through the

suction box.

  Compared to the two canvas trainers described

  above, the draining device according to the invention pre-

  still feels, in addition to a significantly lower capital expenditure, the advantage of a lower operating cost

  weak because, whereas in the case of a two-sheet trainer

  a relatively high vacuum is necessary for the suction box arranged in the upper perforated strip to suck the water from the continuous sheet upwards, in the draining device according to the invention only the pressure with which the perforated cylinder is pressed on the continuous sheet penetrates the water from the continuous sheet into the perforated cylinder, and as already mentioned, a relatively low vacuum is sufficient to bring the water in the perforated cylinder in one go suction box Finally, in the draining device according to the invention, neither all nor a significant part of the perforated cylinder must be

  vacuum, but only the relatively annular region

  strongly weak, in the radial direction, which is

  between the filter cloth envelope and the internal cylinder

  laughing. To form several channels which extend in the peripheral direction between the filter cloth and the inner cylinder, it is recommended to use bars arranged on the latter and extending in the peripheral direction of the perforated cylinder, which support

  the filter fabric directly or indirectly through

  other support elements and which form the channels between them These bars can be formed on

  the inner cylinder, for example by sparing, by cooling

  wise or sawing, grooves which extend along the di-

  peripheral rection in the outer periphery of the cy-

  interior liner However, it is much simpler and less expensive to form the strips using sheet metal rings arranged on edge which are fixed on the cylinder

interior, for example welded.

  To obtain a good uniform support of the fabric

  filter, it is also recommended to combine bars

  rettes adjacent to each other by means of bridges which are arranged at a certain radial distance from the internal cylinder so as not to interrupt the channels which extend in the peripheral direction, and which support the filtering fabric In a manner known per se, these bars can be constituted by sheet metal rings folded in meanders and arranged on edge, which gives particularly advantageous manufacturing costs. It is also advantageous that the bridges or the rings of

  sheet metal folded in meanders slightly protrude

  vant the radial direction with respect to the bars extending in the longitudinal direction, so that the filter cloth is supported only on the bridges mentioned; in this way, the danger of the appearance of marks on the upper face of the continuous sheet is avoided, marks which may moreover be caused by the fact that, due to the centrifugal forces at the level of the

  side walls of the bars extending in the direction

  peripheral, water entrained outward in the radial direction arrives directly on the

filter cloth.

  So that the vacuum applied to the envelope of the cy-

  perforated liner through the suction box

  be as uniform as possible along the cylinder

  drilled, it is recommended to join the channels in the axial direction through openings provided in the bars, whereby, when using sheet metal rings folded in meanders and placed on edge,

  one can foresee the openings of the bars in the best

  their possible position in the vicinity of the inner cylinder so that they do not prevent the application of meandering sheet metal rings on the bars these meandering sheet metal rings must then have a

  certain distance from the following inner cylinder

in front of the radial direction.

  A simple flow possibility is obtained for the water sucked in from the perforated cylinder as well as a simple, tight closure of the suction box when the latter has a flow which enters a siphon which has an overflow whose edge - spillway is higher than the lower edge of the suction box drain. The vacuum can then be applied laterally to the suction box, while the water flowing down from the suction box closes the latter.

tightly.

  When manufacturing the perforated cylinder for

  the draining device according to the invention, it is recom-

  instructed to adapt the height of the channels, measured in the radial direction, between the filter cloth casing and the inner cylinder, to the amount of water which must be drawn into the 'flat table machine for each rotation

of the perforated cylinder.

  Finally, it is advantageous that, for cleaning the perforated cylinder, a water vaporization device,

  in particular in the form of a spray tube

  be placed behind the suction box, in the

  direction of rotation of the perforated cylinder.

  The present invention will be better understood from

  using the following description of an embodiment

  preferred but not limiting, shown in the accompanying drawings in which: Figure 1 shows a portion of a longitudinal vertical section of a flat table machine on which is mounted a draining device; Figure 2 is a sectional view of an end region of the perforated cylinder of this draining device, taken along line 2-2 of Figure 1; Figure 3 shows section "A" of Figure 1, on an enlarged scale; Figure 4 is a sectional view along line 4-4 of Figure 3, and Figure 5 is a plan view of the parts shown in Figure 4, seen in the direction of the

  arrow B, but without the filter fabric envelope of cy-

perforated liner.

  Figure 1 shows a machine bench 10

  a flat table machine which supports, through

  diary of supports not shown, a table 12 with

longitudinal supports 14.

  Between two of these longitudinal supports available

  located at a certain distance from each other according to the di-

  transverse section, a large number of wheels are provided

  support waters 16 mounted so that they can rotate and

  through which the long canvas is drawn

  tudinal 18 of the machine As is common, it

  git of a band of endless filter cloth which is entrained

  born, by means not shown, in the direction of the arrow Several suction boxes 20 fixed on the longitudinal supports 14 are arranged along the table 12 under the longitudinal fabric, in order to remove the water down one continuous sheet 22 disposed on the longitudinal fabric 18 Since the flat table machine has a very common constitution,

  there is no need to describe it in more detail.

cut.

  To be able to remove water from the conti-

  naked 22 also from above, there is provided a draining device designated as a whole by the reference 26, which comprises a perforated cylinder 28 whose shaft 30 extends parallel to the table 12 and perpendicular to the direction of advance of longitudinal fabric 18 Cormme on

  can see in Figure 2, the shaft 30 of the cylinder per-

  drilled is subdivided and supports an inner cylinder 34 of the perforated cylinder, by means of support and front discs 36 and 38 respectively The metal cylinder

  interior 34 has a closed wall and supports bars

  strips 40 extending in the peripheral direction and arranged at a certain distance from each other, bars for which it may be elongated sheet rings arranged on edge, which are rigidly welded

  on the inner cylinder 34 Between the bars 40

  tend bridges 42 which are formed by meandering rings 44 welded on the bars, bridges for which they are sheet metal rings folded in meanders arranged on edge On the bridges 42 and the bars 40 is supported a filter cloth 46 which has been called a single-layer filter cloth casing, but must consist of at least two layers of filter cloth, namely an outer fabric, metallic or made of synthetic yarn,

  with extremely fine mesh, and an insulating support layer

coarser interior.

  The perforated cylinder 28 is mounted on bearings 48 fixed on the longitudinal supports 14, and on which are articulated two support levers 50 receiving between them the perforated cylinder The shaft 30 of the perforated cylinder is mounted in these support levers, and for adjusting the distance of the perforated cylinder 30 from the longitudinal fabric 18, support screws 52 are used

  extending between the longitudinal supports 14 and the

  support plates 50, screws which allow fine adjustment of

  the pressure with which the perforated cylinder 28 is applied

  puyé against the continuous sheet 22 For this purpose, the support screws 52 are provided with two threads of opposite pitch (see FIG. 2), which engage in corresponding threaded bores of the longitudinal supports and the support levers 50 One end of the shaft 30 of the perforated cylinder is crossed by the associated support lever 50

  and is coupled to the shaft of a drive motor 54.

  We will now explain in more detail the constitution of the perforated cylinder 28, using the figures

  3 to 5 Between the wall of the inner cylinder 34, the bars

  rettes 40 and the meandering rings 44 are formed of

  nals 60 extending in the peripheral direction of the perforated cylinder 28? channels which communicate with each other via openings 62 formed in the bars 40 in the vicinity of the inner cylinder

  34, because of which front disks 38 which extend

  tooth to filter cloth 46 in the direction of

  diale are however sealed in the axial direction The meander rings 44 fixed on the bars 40 at a certain distance from the inner cylinder 34 have recesses 64 in their sections which extend parallel to these bars, which offers

  the advantage that also in the place where the rings in mean-

  dres are fixed on the bars 40, the thickness of the grill

  , the thread supporting the filter cloth 46 is no more important

as much as in other places.

  On the longitudinal supports 14 is fixed a

  suction box, designated as a whole by the ref-

  rence 70, which surrounds the peripheral region which moves upwards of the perforated cylinder 28 driven by the drive motor 54 in the direction of the arrow, and which is

  coupled, via a suction tube 72 mon-

  tee on a side wall, to a fan 74 which

  maintains a certain vacuum in the suction box For this purpose, the suction box is sealed against the

  perforated cylinder 28, by means of strips 78 for-

  mant of the so-called labyrinth boxes, together with the

perforated cylinder 28.

  The mentioned labyrinth boxes are known and represent nothing other than a narrow gap which is sealed in isolation by circulating water which

happens in the meantime.

  Behind the suction box 70, in the direction of rotation of the perforated cylinder, is arranged another box 80 in which is located a spray tube 82 extending along the perforated cylinder 28 and with the help of which water is sprayed against the outer face of the perforated cylinder 28, to clean the filter cloth 46 and the support mechanism which is located below A sealing lip 84 made of felt, rubbing against the perforated cylinder

  28, is also used for sealing the body 80.

  At the lower end of the case

  suction 70 opens therein a drain tube

  ment 86 which arrives in a siphon 88 whose edge-

  weir 90 is located higher than the lower end of the drain tube 86 A drain tube of the siphon 88 is designated by the reference 92 In this way we obtain that no loss of vacuum can appear

  more via the drain tube 86.

  When the perforated cylinder 28 is pressed on the continuous sheet 22, water from the sheet

  continuous enters the interval between the internal cylinder

  laughing 34 and the filter cloth 46, passing through the filter cloth 46, and its projection on the continuous sheet 22 as a result of centrifugal forces is prevented by the vacuum applied at this space, even in the case of a

  perforated cylinder rotating rapidly.

  When it reaches the suction box 70, this-

  the water is entrained through the filter cloth 46 and

then flows.

  The amount of water removed from the top of the continuous sheet 22 can be regulated by means of the vacuum in the suction box 70 and by means of the screws

  support 52, by adjusting the pressure exerted by the cy-

  perforated liner 28 on the continuous sheet.

  Naturally, the draining device according to the invention should not be placed just in the region of one of the water removal elements which are located under the longitudinal fabric 18, such as for example one of the

suction boxes 20.

  From the above, the characteristic es-

  of the invention turns out to be that the cylinder per-

  drilled has at least one vacuum chamber which extends along the periphery of the perforated cylinder, between the filter cloth and the inner periphery of the cylinder

  interior This is sealed against the exterior.

  laughing by the filter cloth in the openings of which the adhesion retains water against the action of the difference between the centrifugal forces and the forces of the vacuum, except in places where the vacuum is applied to the

  perforated cylinder and where water comes out of the filter cloth.

Claims (11)

  1 Drainer to remove water from a continuous sheet on a perforated strip   of a flat table machine, comprising a perfo-   re (drip roller) mounted so as to be able to rotate, can be applied to the continuous sheet and comprising a filter cloth forming its outer periphery, as well as a suction box arranged at the level of the outer periphery of the perforated cylinder, characterized by the fact that the perforated cylinder (28) has an inner cylinder   (34) closed on its periphery and supporting the thread-   trant, as well as, between this inner cylinder and the filter cloth (46), at least one channel (60) which extends in the peripheral direction and is closed in a sealed manner in the axial direction with respect to the front faces (38) of the perforated cylinder, and that to draw water from the filter cloth (46), the suction box (70) is arranged at the outer peripheral region, which rotates   upwards, from the perforated cylinder (28).   2 Device according to claim 1, charac-   merited by the fact that bars (40) are arranged on the inner cylinder (34), extending along the   peripheral direction of the latter, bars which   carry the filter cloth (46) and form therebetween channels (60).   3 Device according to claim 2, charac-   terrified by the fact that neighboring bars (40) are joined together by means of bridges (42) which have a certain radial distance from the inner cylinder (34) and support the filter cloth (46).   4 Device according to claim 2, charac-   terrified by the fact that the bars (40) are formed by   elongated sheet metal rings arranged on edge.   5 Device according to claim 3, charac-   terrified by the fact that the bridges (42) are formed by   sheet metal rings (44) folded in the form of meanders and posed of song.   6 Device according to any one of the re-   vendications 2 to 7, characterized in that the channels (60) communicate with each other in the axial direction through openings (62) provided in the bars (40).   7 Device according to claim 6, charac-   terrified by the fact that the openings (62) of the bars   are located in the vicinity of the inner cylinder (34).   8 Device according to any one of the re-   vendications 1 to 7, characterized in that the height, measured in the radial direction, of the channels (60), is chosen in correspondence with the quantity of water which must   be aspirated for each rotation of the perforated cylinder.   9 Device according to any one of the re-   previous vendications, characterized in that the suction box (70) has a drain (86) which enters a siphon (88) which has an overflow (90) whose overflow edge is located higher than the edge   lower of the drain (86) of the suction box.   Device according to any one of the re-   Vendications 1 to 9, characterized in that a pipe (72) leading to a fan (74) is connected to a   side wall of the suction box (70).   11 Device according to any one of the re-   urgent claims, characterized by the fact that   the suction box, in the direction of rotation of the   perforated liner, a spray device is arranged   of water (82), for cleaning the perforated cylinder (28).   12 Device according to any one of the re-   previous vendications, characterized in that the front delimitation of the suction box (70), in the direction of rotation of the perforated cylinder (28), is only slightly above the upper edge of the periphery of the perforated cylinder.