FR2536097A1 - FRACTIONATION INSTALLATION OF A FIBER SUSPENSION - Google Patents

Abstract

A. INSTALLATION FOR SEPARATING A SUSPENSION OF FIBERS INTO A FRACTION MAINLY LONG FIBERS AND A FRACTION MAINLY SHORT FIBERS, WITH A FRACTIONING APPARATUS. B. INSTALLATION CHARACTERIZED BY AN APPARATUS-DETECTOR OF THE CONCENTRATION OF MATERIAL 4 IN THE LONG FIBER CONDUCT LF TO CONTROL THE OPENING OF A CHANGING BODY 5 PROVIDED FOR IN THE LF LONG FIBER CONDUCT PROPORTIONALLY TO THE MEASURED CONCENTRATION 'INTERMEDIATE OF A REGULATING ORGAN 3. C. THE INVENTION CONCERNS IN PARTICULAR THE TREATMENT OF FIBER SUSPENSIONS.

Description

"Fractionation plant of a suspension of

fibers ".

  The present invention relates to an

  fractionation of fiber suspension into a fraction having mainly long fibers and a fraction having mainly short fibers, with

a fractionation apparatus.

  Such an installation is known according to the publication "Wochenblatt fur Papierfabrikation" 10 (1981) pages 334 to 339, in particular page 337, right column In this installation, it is attempted using a known power setting, to arrive to an operating behavior of the fractionation apparatus

  as high as possible and with a high return

  That is to say, a separation as good as possible of long fibers and short fibers. This adjustment of the yield consists, in known manner, of working in the vicinity of the maximum load of the sieves and when appearances of overload occur on the motor drive, reduces the power that is to say that one strangles the

  flow, or that strangling is less of a

  especially for the long-fiber fraction

  This process, however, does not correspond to a solution

  optimum, requires a very largely constant flow rate ie the suspension of treated fibers, and there is the risk of nevertheless having a sieve stuffing

  and a failure of the installation.

  The object of the present invention is to create an installation that makes it possible to perform a correct splitting and thus while operating in the vicinity

  immediately from the jam limit, to obtain an

  in safe operation, ie with interrup-

  operating conditions as small as possible.

  For this purpose, the invention relates to a

  installation of the above type, characterized by an

  detecting the concentration of material in the conduit-long fibers to control the opening of a throttling member provided in the conduct of long fibers in proportion to the concentration

  measured by means of an adjusting member.

  Concentration detection devices

  are widely used as measuring devices used in the preparation of old

  However, their use was only

  now not in the sense of the invention and in fractionation operations, at most as follows by a material concentration detecting apparatus provided in the inlet line of the fractionator, and which is connected to a consistency adjusting member acting on a restriction point provided in the dilution water supply pipe

  for the inlet line of the fractionator.

  These detection devices are to some extent

  precise, so that they can detect deviations

  consistency of 0.1%. In this way, the installation

  tion is very sensitive and has the best efficiency

  cited despite relatively simple constructive means.

  This puts the operational safety at its level the

higher.

  It would of course be possible to

  to kill a measure of quantity by determining, for example, the vein of long fibers to determine whether the flow rate is sufficient. However, such a measure could be done with great precision only by using very important means. Even in this case, the results do not would not be as favorable as in the process

according to the invention.

  The present invention will be described in more detail with the aid of the single attached figure which is a

diagram of the installation.

  According to the figure, the reference 1 denotes a fractionation apparatus, the reference 4 the concentration detection apparatus in the long fiber pipe downstream of the fractionation apparatus 1; the

  reference 2 denotes a concentration detection apparatus

  In the long fiber conduit Lf there is provided a throttle member 5 behind the concentration detection apparatus 4, which is in the form of a drawer or a ball valve and in the short fiber conduit Kf, there is an organ

  corresponding bottlenecks The openings of these organizations

  Throttling units are controlled from the concentration detection apparatus 4 by the consistency adjusting member 3. This provides an output signal to the pneumatic calculation relays 9 and 10. Under these conditions the relay 10 acts on the throttle member in the short fiber cord Kf, its input signal being

  applied by means of a reversing element 11.

  This ensures that both throttles

  essentially open or close in opposite directions.

  A consistency adjusting member 8

  is also connected to the

  resistance 2; this member 8 acts on the valve 16 of a con -

  water slurry 15 and which can supply water of dilution,

  the suspension to arrive in this way to a

  constant rate at the input of the

1.

  With the aid of manual stations 18 and 19, corrections can still be made - The fractionation device 1 then operates at a rate such that the screen itself is working at the edge of the jam.

  of consistency 3 notes through its

  consistency detection wheel 4 that it establishes a high consistency in the conduct of long fibers, it means at the same time the observation that the risk of jamming of the sieve increases For this, the adjustment is made so that in such a case the throttle 5 continues to open to reduce the risk again

  Frying the sieve of the fractionator 1.

  In the opposite case, using this consistency detection apparatus and the consistency adjusting member, the apparatus is also operated so that it is almost always in the vicinity of the stuffing limit of its machine. Thus we arrive at the best effect of splitting But at the same time, security

  of operation according to this method is the largest.

  The installation also allows for

  variable quantities of matter to the extent that these variations do not differ by more than 30% of the nominal value, downwards.

  possible only to a small extent.

Claims (1)

CLAIMS) Apparatus for separating a fiber suspension into a fraction having mainly long fibers and a fraction having mainly short fibers, with a fractionating apparatus, an installation characterized by an apparatus for detecting the concentration of material (4). ) in the long fiber duct (Lf) for controlling the opening of a throttle member (5) provided in the duct of the long fibers (Lf) in proportion to the concentration measured via an organ adjustment (3). Installation according to claim 1, characterized by a material concentration detecting apparatus (2) provided in the inlet line (14) of the fractionation apparatus (1), which is connected to a consistency adjusting member (8) acting on - a throttling point (1e) provided in the dilution water supply line (15) for the inlet line (14) of the apparatus fractionation (1).   30) Installation according to any one   claims 1 or 2, characterized by an organ of   ratio setting (9, 10) for the throttle points (5, 6) of the long fiber line or the short fibers (Lf, Kf).