Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/022—Heating the cylinders
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/021—Construction of the cylinders
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/06—Regulating temperature
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F7/00—Other details of machines for making continuous webs of paper
  • D21F7/003—Indicating or regulating the moisture content of the layer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
  • F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
  • F26B13/14—Rollers, drums, cylinders; Arrangement of drives, supports, bearings, cleaning
  • F26B13/18—Rollers, drums, cylinders; Arrangement of drives, supports, bearings, cleaning heated or cooled, e.g. from inside, the material being dried on the outside surface by conduction
  • F26B13/183—Arrangements for heating, cooling, condensate removal

Definitions

• the present invention relates to paper machines, and it relates more precisely to a drying cylinder intended for the equipment of a dryer and / or a post-dryer of a paper, cardboard or other material bandaged.
• the cylinders or drying drums are arranged in two rows, one upper and one lower, and are generally grouped in batteries of three to twenty cylinders, each battery being associated with its felt, which develops downwards or downwards. high, and each felt being dried by a felt drum or drum.
• the strip of paper passes successively from a lower drying cylinder to an upper drying cylinder, and vice versa. Blowers, conveniently arranged, peel off the thin film of air saturated with vapor which tends to form continuously on the strip of wet paper and to stagnate there, and the fumes released are collected by a hood and evacuated. In these dryers with drying cylinders heated internally with steam, it is accepted that 1.3 to 1.5 kg of steam are necessary, depending on the installations and the nature of the paper pulp, to evaporate a liter of water contained in the strip. wet paper. In more recent drying works,
• each drying cylinder has been surrounded by an individual hood pierced with multiple orifices, in the form of holes and slots, in communication with an installation for blowing hot air and extracting fogging.
• the strip of paper After being passed over one or two cooler cylinders, which are mounted at the outlet of the dryer or post-dryer, the strip of paper can be considered as being completely formed and then wound up in mother reels.
• the paper strips undergo, before being wound up in master rolls, treatments intended to improve their surface condition and / or their internal structure.
• the strip of paper leaving the dryer or post-dryer is received in a heddle responsible for improving the surface condition, while the internal structure of the paper can be improved by moistening the strip of paper leaving the dryer with the help of wetting or moistening machines.
• a moistening machine is a device which sprays water, in the form of droplets as small as possible, on the strip of paper leaving the dryer, in order to restore it to a humidity of between 5 and 10% approximately.
• the rail is a vertical mechanical device comprising several carefully polished metal rollers, resting horizontally on each other and clamped together with an adjustable force, by means of a frame.
• the strip of paper coming out of the cooling rollers passes between the rollers of the heddle, which are cooled or heated by external blowing of air through nozzles, in order to contract or locally expand the metal and to correct, where it is necessary, the defects that the paper strip can present in its thickness.
• the smoothing decreases, by simple compression, the natural roughness of the paper.
• the treatment for improving the surface condition can also be accomplished outside of the paper machine, in a calender comprising several rollers alternately of polished metal and of compressed and rectified paper. " Calenders, which are very heavy and
• the object of the invention is to propose a drying cylinder which overcomes the drawbacks of the drying cylinders of the state of the art in terms of regulation, and such that a certain number of cylinders according to the invention can be substituted and / or added to certain known cylinders, downstream of a certain number of these cylinders, in order to correct the humidity profile in the dry or post-dry.
• the main object of the invention is to provide a drying cylinder which allows better control of the humidity profile and the thickness profile of the strip of material, and which fulfills, at least partially, the functions usually performed by dampers and / or healds or calenders, so that the latter devices can be otherwise eliminated, at least simplified in their production, or that the overall result is improved and obtained more quickly.
• the drying cylinder according to the invention intended for the equipment of a dryer and / or an after dryer of a strip material machine, in particular paper, and of the type having a hollow framework heated internally and having a cylindrical external lateral surface, of circular cross section, against which a strip of material is intended to be applied, is characterized in that the external lateral surface is delimited by several cylindrical rims, of cross section circular, of the same radius, arranged coaxially side by side, and made of a material which is a good conductor of heat, each rim being in heat exchange relation with an internal heating device with individual control which the rim surrounds, and each rim being integral in rotation with at least one hub wedged on at least one cylinder rotation shaft.
• each rim is also in heat exchange relation with an internal cooling device with individual control that the rim surrounds, because then, each rim can be successively heated and cooled, as required along the longitudinal edge of the width applied against the corresponding rim, in response to correction signals from appropriate detectors, such as those currently used in paper machines.
• each rim is directly in contact, and integral in rotation, with an underlying member which it surrounds and which contains at least one heating member of the corresponding heating device and / or one cooling member of the cooling device. correspon ⁇ dant, so that the rim is heated and cooled by conduction, which is an efficient heating and cooling mode, good performance, and flexible in terms of regulation.
• each rim is separated from the neighboring rim or rims by a small axial space.
• the two axial ends of the cylinder are closed, in order to avoid, during rotation, the energy losses by ventilation.
• the interior of the cylinder is connected to a source of vacuum, so that the sheet of material is sucked against the rims, by the free axial spaces between the latter, which makes it possible to promote heat exchanges. between the cylinder and the strip of material
• the heating device is an electrical device, the heating member of which comprises an electrical resistance supplied with power from the outside of the cylinder, which can be produced in a relatively simple, compact and inexpensive manner, with good energy efficiency.
• the heating device is a device for circulation of a heat-carrying fluid, the heating member of which comprises a tubular element through which a hot heat-carrying fluid passes.
• Other heating means can also be envisaged, for example induction heating.
• the device for cooling each rim it is advantageously produced in the form of a device for circulating a cooling fluid in a tubular cooling element, an inexpensive and practical cooling fluid for this purpose being for example cold water.
• the circulation of a fluid in a tubular element of a cooling device and / or a heating device can be controlled by an electrically controlled valve, while the electrical supply of the resistance of a heating device electric and / or the valve of a cooling device and / or a heating device can be controlled by a relay clocked in the cylinder.
• each relay is for example switched by an independent remote control.
• the remote control comprises a receiver specific to the relay corresponding and sensitive to a particular control frequency of a transmitter common to all the relays and to several transmission frequencies, in number corresponding to the number of relays, the transmitter being itself controlled, for each frequency, by an interrup-
• each relay is switched, for example, by an individual photoreceptor cell, which is attached to it, and which picks up a particular light beam.
• each relay is a relay with proximity microswitch actuated by a comb tooth introduced into an axial space between two rims, which makes it possible to make the most of the presence of a separation comb between the strip of material and the cylinder.
• FIG. 1 is a partial perspective view of a drying cylinder according to the invention
• FIG. 2 is a partial schematic view in axial section of the drying cylinder of FIG. 1, and
• FIG. 3 is a diagram illustrating the principle of the electronic control of the drying cylinder shown in FIGS. 1 and 2.
• the drying cylinder 1 consists of several rims 2, cylindrical, of circular section and of the same radius, made of copper or stainless steel, each of which is secured to a underlying organ 3, hereinafter called the rim.
• each sub-rim 3 has the shape of a circular ring of cross section substantially in an isosceles trapezoid with slightly curved inclined sides and surrounded by the corresponding rim 2 which the sub-rim supports.
• each sub-ante 3 also made of copper or stainless steel, is integral with the internal face of the corresponding rim 2, while by its small base, facing inwards, the sub rim 3 is connected by three rigid spokes 4 to the external lateral surface of a hub 5 having an axial passage by which the hub 5 is secured in rotation with a drive shaft 6, for example by keying or by splines, La axial dimension of each hub 5 is slightly greater than that of the corresponding rim 2, so that all of the rims 2, the sub-rims 3, the spokes 4 and the hubs 5 abutted against each other, either assembled and wedged on the shaft 6, so that a free space 7 of about 1 mm wide separates two adjacent rims 2.
• the external cylindrical lateral surface and of circular section of the drying cylinder 1 is thus delimited * by the polished external lateral surfaces of five to ten independent rims 2 per meter of width, the rims 2 being mounted coaxial, side by side, and separated in pairs by an axial space 7, the drying cylinder 1 having the same external dimensions as steam-heated drying cylinders of the prior art, that is to say an external diameter of approximately 1.5 m and a length between 1.5 and 10 m.
• Each independent rim 2 is associated with a heating device and a cooling device for this rim 2.
• Each heating device comprises an electric heating element in the form of an electrical resistor 8 housed in a toric channel embedded in the rim 3 corresponding.
• This electrical resistance 8 which, by the Joule effect, ensures the heating of the sub-rim 3, and therefore by conduction the heating of the rim 2, is supplied with power by a supply line (not shown in the figures 1 and 2) extending radially along or in a radius 4, then passing through the corresponding hub 5 and the shaft 6, and then extending in the shaft 6, which is hollow, up to two rotating collector rings 9, carried by the shaft 6 on one of its two axial ends. against these rings 9 are applied fixed brushes connected to the electrical distribution network 5.
• the supply of the heating resistor 8 is regulated by a control member in the form of a relay 10, which is mounted on the corresponding power supply line, remotely controlled from outside the cylinder 1 0 and disposed on a radius 4, near the corresponding hub 5.
• Each cooling device which is circulating with a cooling fluid, also comprises a cooling member and a control member.
• the cooling member is a toric channel 11, which is also embedded in the corresponding sub-rim 3, and which is traversed by a flow of water. This water, which enters cold into the channel 11, is heated, by conduction.by the sub-rim 3 and by the rim 2. who . are thus cooled.
• the channel 11 is connected to a cold water supply pipe and to a heated water discharge pipe (not shown in FIGS.
• each channel 11 The circulation of water in each channel 11 is regulated by a control member in the form of a solenoid valve 12, arranged on a radius 4, near the corresponding hub 5, the electrical control of which is provided by an integrated and remote-controlled relay in the same manner as relay 10.
• a control member in the form of a solenoid valve 12, arranged on a radius 4, near the corresponding hub 5, the electrical control of which is provided by an integrated and remote-controlled relay in the same manner as relay 10.
• Each rim 2 can thus be successively heated and cooled, independently of the others, by the individual control of the heating and cooling devices associated therewith, as required and in accordance with control signals which are produced, for example by computer, as a function of detection signals coming from humidity or thickness detectors suitably arranged opposite the paper strip, as is the case in the paper machines of the prior art.
• control signals are transmitted to each relay controlling the supply of the corresponding heating resistor 8 or the corresponding solenoid valve 12 by an independent remote control.
• the spokes 4 of the different sub-assemblies can be connected by threaded tie rods 13, which pass through the spokes 4 parallel to the axis of rotation of the shaft 6 and are rigidly fixed to each spoke 4 by two nuts 14 screwed onto the corresponding tie rod 13 and tightened on either side of the spoke 4 against the external lateral surface of the latter.
• the different spokes 4 thus connected by a tie rod 13 are kept apart at constant distances from each other.
• FIG 3 there is schematically shown an embodiment of an electronic remote control for heating and cooling a drying cylinder such as 1.
• Each rim 2 corresponds to two stati ⁇ cal frequency controlled relays, which are each switched by an alternating control signal having a particular frequency.
• the relay 10 associated with its particular receiver sensitive to a first frequency
• WIPO particular controls the supply of the heating resistor 8 connected in bypass to an internal and bipolar electric line 15 for supplying power to all the heating resistors 8 and all the solenoid valves 12.
• This relay10 is also mounted in derivation on the internal power supply line 15.
• Each solenoid valve 12, also connected in bypass on the internal line 15, is controlled by its integrated static relay 12 ', itself associated with its particular receiver, sensitive to a second particular frequency, and in bypass on the internal line 15
• the two wires of the latter are each connected to one of the two rotating slip rings 9 of the shaft 6, against which a fixed brush 16 of an external and bipolar power supply line 17 is applied, in derivation on a line 18 for supplying power to the sector, for example by alternating current at 220 V, by means of a protective interrup ⁇ 19 housed in a box or control console 20 '.
• the latter essentially contains a single transmitter 21 of alternating signals which is connected in deviation to the line of the sector 18, by means of a second protection switch 22.
• This transmitter 21 can transmit signals at particular frequencies including the number corresponds to the sum of the number of the heating resistors 8 and the number of the solenoid valves 12, and this transmitter 21 is controlled by switches 23 in number equal to the number of the particular emission frequencies.
• the transmitter 21 is also connected to the external power supply line 17, downstream of the protection switch 19, so that each signal, transmitted at a particular frequency, passes through the power supply lines. power 17 and 15 to reach relay 10 or relay 12 'which is sensitive to this particular frequency.
• WIPO as well as the cooling or stopping of the cooling of this rim 2 by the opening or closing of the corresponding solenoid valve 12 are controlled by the emission or the interruption of the emission by the transmitter 21 of a signal having a particular frequency and which is received by a relay 10 or by a relay 12 'switched by this signal.
• the switches 23, which each control the emission of a signal at a particular frequency are actuated automatically in any suitable known manner, in order to obtain automatic regulation of the heating and / or cooling of the rims 2, independently one of the other.
• the cylinder 1 is closed in a relatively airtight manner at its two axial ends, as is schematically represented on the right axial end of the cylinder 1 in FIG. 3
• This can be achieved using two radial discs such as 24, one of which delimits around the part of the shaft 6 which passes through it a suction opening connected by an external bell 25 to a source of vacuum. , so that the slight depres ⁇ sion prevailing in the rotating cylinder 1 causes suction at the axial spaces 7 between the rims
• the material strip for example of paper
• the material strip is sucked up and well applied against the external lateral surface of the rims 2, which promotes heat exchanges between the rims 2 and the paper, the profile of which can thus be corrected. humidity.
• a contribution of moisture to an excessively dry zone of the paper is obtained due to the condensation which results from the cooling of the rim (s) 2 against which this zone of paper is applied, while the evaporation at the levels heated rims 2 dehydrate excessively damp and corresponding areas of the paper.
• drying cylinder 1 participates in the correction of the paper thickness profile, since it is placed upstream of a heddle for example, to which the strip of paper, locally heated or cooled in adjacent longitudinal zones and transverse, will bring more or less heat.
• the heating device can also be a device for circulation of a hot heat-transfer fluid, the flow of which in a channel such as that which is traversed by the cooling fluid, is controlled by another solenoid valve with piloting electric provided by a relay.
• each relay can be controlled by a particular photoreceptor cell, which picks up a particular light beam, or alternatively each relay is a relay with proximity microswitch, actuated by the tooth 27 of the comb 26 which is engaged in an axial space 7 adjacent to the corresponding rim 2.
• the relays can also be corrr ⁇ uted by radio waves, without transit through the power line.
• the strip of material can be applied against the rims by a felt by atmospheric pressure if the cylinder is in depression, or by the tension of winding of the strip around the cylinder. / " ⁇ JBÎ

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Drying Of Solid Materials (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (2)

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ID=9293582

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• 1983
  • 1983-10-27 FR FR8317132A patent/FR2554137B1/fr not_active Expired
• 1984
  • 1984-09-28 CA CA000464303A patent/CA1238487A/fr not_active Expired
  • 1984-10-24 WO PCT/FR1984/000242 patent/WO1985001969A1/fr active IP Right Grant
  • 1984-10-24 DE DE8484903962T patent/DE3476231D1/de not_active Expired
  • 1984-10-24 EP EP87201497A patent/EP0252572A1/de not_active Withdrawn
  • 1984-10-24 EP EP84903962A patent/EP0160060B1/de not_active Expired
  • 1984-10-24 US US06/752,197 patent/US4627176A/en not_active Expired - Fee Related
  • 1984-10-24 JP JP59503913A patent/JPS61500856A/ja active Pending
• 1985
  • 1985-06-13 FI FI852360A patent/FI77491C/fi not_active IP Right Cessation

Non-Patent Citations (1)

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