FR2765124A1 - SPRAY NOZZLE AND SPRAYING SYSTEM FOR SPRAYING LIQUID ONTO A STRIP OF MATERIAL - Google Patents

Abstract

A spray nozzle for spraying liquid onto a web of material, in particular for spraying separating liquid onto aluminum foil, has a central liquid nozzle (28), connected to a liquid inlet (27) and having a tubular outlet channel (29). The outlet channel (29) opens, together with an air inlet channel (31) whose outlet opening (32) is arranged in a ring around the outlet channel (29), in a cover (33) with a slit-shaped outlet opening, acting as a flat jet distributor To be able to continuously adjust the spray rate between very wide limits, exclusively through the liquid pressure, the outlet channel (29) of the liquid nozzle (28) has an internal diameter of 0.3 mm or less and a length corresponding to more than 30 times its internal diameter.

Description

Spray nozzle and spray system for spraying

  The present invention relates to a spray nozzle and to a spray system for spraying liquid onto a strip of material, in particular for spraying a separation liquid.

on aluminum foil.

  When making extremely thin aluminum sheets, it is necessary to pass

  two strips of sheets superimposed across a lami-

  black in order to bring them to the small thickness required,

  until 6 pm. For this purpose, before rolling,

  read by winding a reel of two superposed sheets

  sées, on a so-called doubling machine. After the last rolling pass, the two sheets are again separated and wound on a so-called separating machine

  as two separate coils.

  So that the two strips of sheets do not weld together during rolling, a separation liquid, for example petroleum or kerosene, is sprayed with suitable additives on the inner face of one of the two strips of sheets, before dubbing. After separation, the coils are heated

  in an oven so that the separation liquid is volatile

  tilise. Separation liquid is applied using

  a spray system which consists of a row

  spray nozzles distributed over the width of the strip. In known manner, two-part nozzles are used, the separation liquid being sprayed using compressed air. However, it has turned out in practice that the known two-material nozzles are not able to spray separation liquid at a

  sufficiently adjustable flow rate and with the necessary uniformity

  to be. The present invention aims to provide a spray nozzle which makes it possible to spray separation liquid, at a rate adjustable between wide limits, and with the necessary uniformity. The invention has

  also intended to provide a spray system

  sation using spray nozzles according to the invention, for spraying liquid

separation.

  The spray nozzle according to the invention

  for spraying liquid onto a strip of material

  riau, in particular for spraying separation liquid on an aluminum foil, comprises a central liquid nozzle, connected to a liquid inlet and having a tubular outlet channel, a

  air intake channel with an outlet opening

  placed in a ring around the outlet channel of the liquid nozzle, and a cover acting as a flat jet distributor and having a slot-shaped outlet opening into which the outlet channel of the liquid nozzle and the channel open air inlet. The outlet channel of the liquid nozzle has an internal diameter of 0.3 mm maximum and a length corresponding to more than 30 times its internal diameter.

  The spraying system according to the invention

  tion to spray liquid on a strip of material

  riau, in particular for spraying separation liquid on aluminum foil, comprises more

  several nozzles according to the invention arranged in a mon-

  nozzle holder ture at equal distance from each other

across the working width.

  Using the spray nozzles according to the invention, the separation liquid can be distributed uniformly by means of a constant pressure of the transport or carrier fluid (air) of 1 bar. The flow

  can be adjusted continuously exclu-

  through the pressure of the liquid, on a

  very wide range of for example 300 cm3 / h to 6000 cm3 / h.

  This excludes turbulence, only the actual quantity-

  dosed per m2 (of material strip) being applied

  without significant losses and without formation of drops.

  Since the application is carried out without significant losses, it is not necessary to provide expensive extraction installations, in order to exclude

  pollution of the workplace or the environment

  is lying. In addition, due to the essential application-

  lossless, it is possible to reduce consumption

  separation liquid, so the cost.

  Preferably, each nozzle can be fixed with the possibility of angular orientation (rotation) around

  from its central axis on a common support cross member.

  In this case, it is possible to provide an adjustment control for an angular orientation.

(rotation) common of the nozzles.

  The nozzles can be connected to common distribution tubes for the separation liquid and the air, which tubes are dimensioned so as to prevent significant pressure drops across the width.

of work.

  Preferably, the distribution of liquid by the nozzles can, the air pressure being constant, be

  adjusted through the liquid pressure.

  The invention will be described below in more detail using an embodiment illustrated in a simplified manner by the accompanying drawings in which: - Figure 1 shows the diagram of an installation comprising a doubling machine and a spraying system; - Figure 2 is a cross section of a spray system; - Figures 3a and 3b are schematic plan views showing the angular orientation of the nozzles;

  - Figures 4a and 4b show the pattern of pul-

  verification of a nozzle in different adjustment positions; - Figure 5 is an enlarged cross section of a spray nozzle; and - Figure 6 is a plan view of the nozzle of the

figure 5.

  The doubling machine shown schematically-

  ment in Figure i includes two unwinding devices

  their 1,2 in each of which hangs a coil 3, 4 of a strip of thin aluminum foil. From the two unwinding devices 1, 2 arranged one behind the other in the direction of unwinding, two strips of sheets 5, 6 are removed, which are brought, by being superposed, to a device 7 for the application by spraying of a separation liquid, for example

  petroleum or kerosene with suitable additives.

  Inside the spraying device 7, the

  two strips of sheets 5, 6 are led parallel-

  at a distance from each other. Between the two bands

  5, 6 is arranged a spraying system 8 which

  checks the separation liquid from below against the

  underside of the upper sheet strip 5.

  The two strips of sheets 5, 6 are then again

  calf superimposed and are brought in the superimposed state to a take-up device 9 o they are taken up

  jointly in the form of a coil 10.

  The spraying system 8 is shown on a larger scale in FIG. 2. It is composed

  a row of elementary nozzles 1 arranged trans-

  across the width of the strip and fixed in a row, at a distance of about 160 mm from each other, in a frame formed by a cross

  12 common support, so that their openings

  outlet res are turned upwards, so that the separation liquid 13 can be sprayed on the lower side of the upper strip 5. The nozzles 11 are connected to common distribution tubes 14, 15 from which they are supplied with liquid (distribution tube 14) and air (distribution tube 15). The distribution tubes 14, 15 are dimensioned so as not to cause a pressure drop at the maximum air and liquid flow rates. This ensures that all of the nozzles 11 receive the same

  liquid pressure and the same air pressure and ejector

  try the same amount of separation liquid 13. So that the spraying system 8 can be adjusted to different working widths, the two external nozzles 11 on each side of the machine can

  be individually disconnected from the distribution tubes

  bution 14, 15, using valves 16.

  As illustrated in FIGS. 3a and 3b, each nozzle 11 is mounted on the support cross member 12 of

  so that it can be oriented angularly by pivo-

  tement around its vertical axis 17, in order to be able to adjust the position of its outlet opening 18 in the form of a slot with respect to the direction of travel of the strip. The adjustment is carried out using an adjustment rod 19 which extends over the working width and on which each nozzle 11 is articulated by its body. The adjustment rod 19 is axially movable by means of a lateral motor 20 and thus makes each nozzle 11 pivot around its vertical axis 17. The angle of adjustment of the outlet opening 18 in the form of a slot in each nozzle 11 relative to the direction of

  tape travel is at least 45, preferably

  rence 60, with respect to the zero position (FIG. 3a) in which the slot-shaped outlet openings 18 are oriented perpendicular to the direction of travel of the strip. By rotation of the nozzles 11, it is therefore possible to vary the width of the jet leaving the nozzle from approximately 300 mm to approximately 160 mm, for the same distance from the nozzles 11 relative to the strip 5. The effect of a rotation of the nozzles 11 from position 0 to 60 is shown in Figures 4a and 4b. The dispensing pattern varies when the nozzles are rotated in the sense that the same dose is sprayed

  on a strip of reduced width. By angular adjustment

  it is possible to adjust the width of the jet which is a function of the flow rate of each nozzle 11 so that the jets of two adjacent nozzles 11 do not

  not overlap. An overlap of two jets causes-

  there will be turbulence which would alter the uniformity of the application. In operation, the nozzles 1 are adjusted so that their application areas just touch each other. It is therefore possible to adapt the spray pattern of each nozzle so as to obtain, for each application rate required per unit of time, a uniform application free from turbulence. As shown in FIG. 2, a cap 21 in the form of a roof, bent towards the edges of the strip, is arranged above the strip 5, this cap preventing, in the event of tearing of the strip 5, dispersion of the liquid cooling coming out of the spraying device 7. On the two edges of the strip, the cap 21 is extended by flanges forming channels 22 extending in the direction of

  running of the strip over the spraying area.

  The channels 22 recover the separation liquid which has not been applied to the strip 5 and lead it through pipes 23 to a reservoir 24. Below

  the nozzle holder mount is arranged in a collecting cup

  25 which collects the separating liquid falling downwards and brings it through a line 26 also to the

collecting tank 24.

  In Figures 5 and 6, there is shown on an enlarged scale an elementary nozzle. The nozzle comprises a central liquid nozzle 28, connected to the inlet

  liquid 27 and having a tubular outlet channel 29

  laire. Around the liquid nozzle 28 is arranged an air nozzle 30 which comprises an air inlet channel 31 whose outlet opening 32 is arranged in a ring

  around the outlet channel 29 of the liquid nozzle 28.

  The outlet channel 29 of the liquid nozzle 28 and the air inlet channel 31 open into a cover 33 with an outlet opening 18 in the form of a slot,

  acting as a flat spray distributor.

  It is essential for the invention that the channel

  outlet 29 of the liquid nozzle 28 has a diameter

  be less than 0.3 mm inside, preferably approx.

  ron 0.1 mm to 0.2 mm, and a length corresponding to more than 30 times its internal diameter. In the example illustrated, the length of the outlet channel 29 corresponds

  about 90 times its inside diameter which is about

  about 0.2 mm. The outlet channel 29 thus formed acts as a restriction (throttle) uniform over its length. Laminar flow does not occur

  disturbed liquid which is injected into the air jet.

  The spray nozzle 11 thus produced can operate with a constant air pressure, the flow rate of sprayed liquid being continuously controlled exclusively by passing through the liquid pressure. The liquid pressure is adjustable between 0.25 bar and 15 bar maximum. With this pressure difference, we

  obtains a liquid flow rate from 300 cm3 / h to 6000 cm3 / h.

  The width of the jet of liquid leaving the slit-shaped outlet opening 18 varies, over this pressure range, between 160 mm and 300 mm. This is corrected by a rotation of the nozzle 11 and therefore by a variation of the angle of the outlet opening 18 relative to the strip (see FIGS. 4a and 4b). With a maximum flow of liquid, a rotation of the nozzle 11 by 60 causes this nozzle 11 to spray the liquid again on a

  strip width of around 160 mm and that it does not

  no turbulence due to the crossing of

  liquid jets from neighboring nozzles 11.

Claims (6)

  1.- Spray nozzle for spraying   tion of liquid on a strip of material (5), in par-   particular for spraying separation liquid on an aluminum sheet, comprising: - a central liquid nozzle (28), connected to a liquid inlet (27) and having a tubular outlet channel (29); - an air inlet channel (31), the outlet opening (32) of which is arranged in a ring around the outlet channel (29) of the liquid nozzle (28); and - a cover (33) acting as a flat jet distributor and having an outlet opening (18) in the form of a slot into which the outlet channel (29) of the liquid nozzle (28) and the channel d air inlet (31), characterized in that the outlet channel (29) of the liquid nozzle (28) has an internal diameter of 0.3 mm maximum and a length corresponding to   more than 30 times its internal diameter.   2.- Spraying system for spraying   liquid on a strip of material (5), in particular   bind to spray separation fluid on a   aluminum foil, characterized in that more   several nozzles (11) according to claim 1 are available.   located in a nozzle holder mount by being arranged at a uniform distance from each other over the working width. 3.- Spraying system according to the   claim 2, characterized in that the various   nozzle annuities (11) are mounted on a common support crosspiece (12) so that they can rotate around their central axis (17).   4.- spraying system according to claim 3, characterized in that it comprises an adjustment control (19, 20) for rotation common nozzle (11).   5.- Spraying system according to one   any of claims 2 to 4, characterized by   causes the nozzles to be connected to distribution tubes   common charges (14, 15) for separation liquid   tion and air, these tubes being dimensioned so as not to be the seat of pressure drops notable on the working width.   6.- Spraying system according to one   any of claims 2 to 5, characterized by   that the distribution of liquid through the nozzles (11) is adjusted by passing through the pressure of the liquid, the air pressure being constant.