EP3000536B1 - Device for cleaning a screen - Google Patents

Description

The present invention relates to a device for cleaning a screen, as well as to a screening installation comprising such a device. The document FR 1 269 298 describes a device according to the preamble of claim 1.

Known screening installations are intended in particular to separate materials, in particular waste, according to their particle size.

In particular, it is known to use screens with a trampoline effect. This type of screen consists of a strip comprising several layers of elastic fabric with holes, attached to cross bars. The bars are subjected to a linear reciprocating motion which alternately stretches and relaxes portions of the webs, causing the materials deposited on the web to bounce.

The movement of the bars deforms the mesh of the canvas, preventing particles from getting stuck in the holes. However, in the case of household waste sorting installations, long fibers are liable to position themselves straddling two holes, causing clogging of the canvas by clogging.

It is therefore necessary to unclog these screens regularly in order to remove the long fibers. Unclogging is generally carried out by manual brushing, or by blowing using a compressed air device handled by an operator. Such operations are tedious and long, especially since the screening fabrics can measure several meters.

There is therefore a need for a device facilitating the unclogging of screens, in particular screens with a trampoline effect.

To this end, the present invention relates to a cleaning device of the aforementioned type, comprising: at least two fixed rails intended to be arranged near the screen, respectively along a first and a second parallel axes; and a mobile blowing carriage. Said carriage comprises: a frame provided with means for movement along the fixed rails; and blowing nozzles connected to means for supplying compressed air, said nozzles being intended to be oriented towards the screen. The compressed air supply means comprise: at least one air supply channel, carried by one of the fixed rails and arranged along the first or second axis; an air collector carried by the frame comprising means for passing the compressed air between the supply channel and the air collector.

• les moyens de passage de l'air comprimé entre le canal et le collecteur comprennent : un orifice d'entrée porté par le collecteur d'air et disposé en vis-à-vis du canal ; une soupape portée par le canal, ladite soupape étant mobile entre une position fermée et une position ouverte, ladite position ouverte permettant un passage d'air hors du canal ; des moyens de passage de la soupape d'une position fermée à une position ouverte au contact du collecteur d'air, de manière à relier le canal d'alimentation en air à l'orifice d'entrée du collecteur ;
• le canal comporte une série de soupapes réparties sur une longueur du rail fixe, une distance entre deux soupapes consécutives étant inférieure à une dimension de l'orifice d'entrée selon l'axe du rail.

According to other advantageous aspects of the invention, the device comprises one or more of the following characteristics, taken in isolation or according to all the possible technical combinations:

• the means for passing the compressed air between the channel and the collector comprise: an inlet orifice carried by the air collector and placed opposite the channel; a valve carried by the channel, said valve being movable between a closed position and an open position, said open position allowing passage of air out of the channel; means for passing the valve from a closed position to an open position in contact with the air manifold, so as to connect the air supply channel to the inlet of the manifold;
• the channel comprises a series of valves distributed over a length of the fixed rail, a distance between two consecutive valves being less than a dimension of the inlet orifice along the axis of the rail.

The present invention further relates to a screening installation, comprising: a web-shaped screen fabric substantially disposed along a third axis; a device for setting the screening belt in motion; and a cleaning device as described above; the third axis being disposed parallel to the first and the second axes and the blowing nozzles of the carriage being oriented towards the screen fabric.

• l'installation comprend un logement situé à une extrémité des rails fixes selon le premier et le deuxième axes, ledit logement étant apte à recevoir le chariot.
• l'installation comprend deux dispositifs de nettoyage tels que décrits ci-dessus, lesdits deux dispositifs étant disposés de part et d'autre de la toile de criblage.

According to other advantageous aspects of the invention, the installation comprises one or more of the following characteristics, taken in isolation or according to all the possible technical combinations:

• the installation comprises a housing located at one end of the fixed rails along the first and second axes, said housing being able to receive the carriage.
• the installation comprises two cleaning devices as described above, said two devices being arranged on either side of the screening fabric.

The present invention further relates to a method of operating a screening installation as described above, comprising the following steps: setting the screening strip in motion; then immobilization of the screening strip; then triggering, by said immobilization, of the movement of the movable carriage along the fixed rails and of the blowing of air through the nozzles in the direction of the screening belt.

Preferably, the installation comprises a housing as described above; during the setting in motion of the screening belt, the trolley is received in the housing, and after the movement of the trolley along the fixed rails, the trolley returns to the housing.

The present invention further relates to a screening installation as described above, provided with means for implementing a method as described above.

• La figure 1 est une vue en perspective cavalière d'une installation de criblage selon un mode de réalisation de l'invention,
• La figure 2 est une vue en perspective cavalière, d'un chariot de nettoyage de l'installation de la figure 1,
• La figure 3 est une vue de détail, en coupe longitudinale, d'un dispositif de l'installation de la figure 1,
• La figure 4 est une vue partielle, en coupe transversale, du dispositif de la figure 3, et
• La figure 5 est une représentation schématique d'un dispositif de mise en fonctionnement de l'installation de la figure 1.

The invention will be better understood on reading the description which will follow, given solely by way of example and made with reference to the drawings in which:

• The figure 1 is an isometric perspective view of a screening installation according to one embodiment of the invention,
• The figure 2 is a perspective view, perspective view, of a cleaning cart of the installation of the figure 1 ,
• The figure 3 is a detail view, in longitudinal section, of a device for the installation of the figure 1 ,
• The figure 4 is a partial view, in cross section, of the device of the figure 3 , and
• The figure 5 is a schematic representation of a device for operating the installation of the figure 1 .

The screening plant 10 of the figure 1 comprises a screening fabric 11, made of elastic material, in the form of a strip substantially arranged along a first axis 12. By way of example, a length of the screen 11 along axis 12 is approximately 7 meters. Preferably, the canvas 11 forms part of a screen with a trampoline effect.

The axis 12 is shown horizontal, however it is possible to have the canvas 11 inclined relative to the horizontal.

On the figure 1 , the canvas 11 is shown substantially flat. However, the canvas 11 is preferably arranged so as to form waves, in particular if said canvas 11 forms part of a screen with a trampoline effect.

The screening fabric 11 is equipped with a setting device which will be mentioned later, so as to alternately stretch and relax portions of the fabric.

The screening installation 10 comprises a device 13 for cleaning the fabric 11. The device 13 comprises a carriage 15, arranged above the fabric 11. The carriage 15 comprises a frame 16 of substantially elongated shape, perpendicular to the frame. axis 12. The carriage 15 further comprises means 17 for movement along two fixed rails 18, 19. In the embodiment described here, the means 17 are sliding pads. Preferably, the pads 17 are coated with a film with a low coefficient of friction, for example containing PTFE (or Teflon).

The movement of the carriage 15 is for example ensured by traction chains 20, connected to a motorization means which will be mentioned later.

The rails 18, 19 of the device 13 are respectively arranged along a second axis 22 and a third axis 23. The axes 22, 23 are arranged parallel to each other and to the first axis 12.

In the example shown in figure 1 , the rails 18, 19 are arranged above the canvas 11, on either side of said strip, the axes 22, 23 forming a substantially horizontal plane.

A length of the rails is preferably substantially equal to, or slightly greater than, a length of the canvas 11. According to one embodiment, at least one of the ends of the rails 18, 19 is disposed a suitable housing (not shown). to receive the carriage 15 when the latter is not in operation.

The carriage 15 is shown on the figure 2 in perspective, from a point of view opposite to that of the figure 1 relative to the plane of the axes 22, 23. The frame 16 comprises two conduits 24, 25 substantially aligned along a fourth horizontal axis 26, perpendicular to the second and third axes 22, 23.

Each duct 24, 25 communicates with blowing nozzles 28, 29, distributed regularly over a length of the duct. In the embodiment shown in figures 1 and 2 , each duct 24, 25 is connected to thirteen nozzles 28, 29. By way of example, a duct 24 or 25 measures approximately 1 m along the axis 26 and the nozzles 28 or 29 are spaced approximately 7.5 cm apart. along the conduit.

Preferably, the nozzles used are composed of several parallel channels, located in the same plane to form a so-called “knife” or “scraper” assembly. The multiple jets of air leaving each nozzle are rectilinear and have a significant impact force under a compressed air pressure of less than 7 bars. Typically, the impact range of these jets is less than 180mm.

The conduits 24, 25 and the nozzles 28, 29 are arranged symmetrically with respect to a plane of symmetry of the frame 16, said plane of symmetry being vertical and parallel to the axes 22, 23.

As shown in figure 1 , the nozzles 28, 29 are oriented in the direction of the screen 11. Preferably, a distance between an outlet of the nozzles 28, 29 and the fabric 11 is approximately 15 cm. The direction of the nozzles is oblique with respect to the first axis 12 in a vertical plane. Preferably, the direction of the nozzles forms with the first axis 12 an angle of between 30 ° and 90 ° and preferably close to 45 °.

Preferably, the nozzles are oriented towards the front with respect to the direction of movement of the frame 16 along the rails 18, 19. According to a variant, it is possible to orient the nozzles substantially perpendicularly to the axis 12 and to the surface. canvas 11.

The frame 16 carries two air manifolds 32, 33, positioned laterally on either side of the plane of symmetry of the frame 16. An inlet mouth 36, 37 of each duct 24, 25 is connected to a manifold 32, 33.

The collector 32 connected to the duct 24 is in particular visible at the figure 2 . The description below of the manifold 32 and of the duct 24 also applies to the other manifold 33 and to the other duct 25.

A side face 40 of the manifold 32 has an air inlet orifice 41. In the embodiment shown in figure 2 , the orifice 41 has the form of two longitudinal slots, located one above the other and separated by a blade 42.

The face 40 of the collector 32 is intended to come into contact with a rail 18, as shown in figure 1 . In order to press the face 40 against the rail 18, the frame 16 is connected to the manifold 32 by compression springs 43. Some of the springs 43 are shown in detailed view in figures 3 and 4 . A similar device connects the frame 16 to the other manifold 33.

In the example shown in figure 2 , the duct 24 has two openings 36, 44 for the air inlet. Each of said outlets connects one end of manifold 32, along second axis 22, to one end of duct 24 along fourth axis 26. This supply of air to each end of duct 18 facilitates pressure balancing in nozzles 28.

Each end of the face 40, along the axis 22, is connected to a tab 45, 46. With respect to the face 40, the tabs 45, 46 move away from the rail 18 and are inclined in the direction of the other rail. 19. A tab 45, shown in detailed view in figures 3 and 4 , therefore forms a ramp 47 oriented obliquely with respect to the lateral face 40 of the collector 32. The other tab 46 has a similar shape.

The rails 18, 19 include channels 48, 49 capable of transferring compressed air to the collectors 32, 33. The channels 48, 49 are respectively arranged along the second axis 22 and the third axis 23. A channel 48 is visible in longitudinal section figure 3 and in cross section at the figure 4 .

The channels 48, 49 are equipped with valves 50 arranged at regular intervals along the axes 22, 23. Preferably, a distance 51 ( figure 1 ) between two consecutive valves 50 on a channel 48, 49 is less than a length 52 ( figure 2 ) Slits forming the inlet 41 of the manifolds 32, 33.

A valve 50 of channel 48 is shown in a detailed view in figures 3 and 4 . The description below of channel 48 also applies to the other channel 49.

The valve 50 comprises a helical compression spring 53, located inside the channel 48. The spring 53 is disposed transversely with respect to the axis 22.

One end 55 of the spring 53 is integral with a wall of the channel 48. Another movable end of the spring 53 is connected to a plug 56, said plug also being located inside the channel 48. In a so-called closed position of the valve 50, spring 53 plate the plug 56 against an orifice 57 of a wall 58 of the channel 48, so as to obstruct said orifice. An external face of the wall 58 is intended to come into contact with the lateral face 40 of the collector 32.

On the stopper 56 is mounted a ball 60. When the stopper 56 is pressed against the wall 58, the ball 60 passes through the orifice 57 and forms a projection outwardly of the channel 48.

The ball 60 is movable in rotation with respect to the stopper 56, around an axis perpendicular to the second axis 22 and to the fourth axis 26. More precisely, the ball is able to roll against the collector 32 when said collector moves according to the axis 22.

In the closed position of the valve 50, the spring 53 is in a partially compressed state, so as to exert a force in the direction of the stopper 56. A pressure exerted in the opposite direction on the ball 60 and / or on the stopper 56 increases the compression. of the spring 53 and moves the plug 56 away from the orifice 57. In this so-called open position of the valve 50, the inside of the channel 48 is in communication with the outside through the orifice 57. As will be explained below, the open position makes it possible in particular to transfer compressed air into a manifold 32, 33 through the orifice 41 of the manifolds.

The screening installation 10 further comprises an electronic device 70 for operating the installation, according to a method which will be detailed below. The device 70 is schematically represented on figure 5 .

The device 70 typically comprises a program memory in which is stored a program 71 implementing the various steps of the method.

The device 70 is able to actuate a device 72 for setting the screen 11 in motion. The device 70 is also able to actuate a motor 73. The motor 73 is for example connected to pinions (not shown) on which are mounted the traction chains 20 of the carriage 15. The starting of the motor 73 moves the carriage 15. along the rails 18, 19, the shoes 17 sliding on the rails.

The device 70 is also able to actuate a compressor 75 which sends compressed air into the channels 48, 49.

According to a variant of the embodiment described above, the carriage 15 and the rails 18, 19 are arranged below the fabric 11, the nozzles 28, 29 remaining oriented towards the fabric 11.

According to another variant, the installation 10 comprises two cleaning devices, similar to the device 13 described above. More precisely, each cleaning device comprises a carriage 15 and rails 18, 19 as described above. One of said cleaning devices is arranged above the canvas 11 and the other of said cleaning devices is arranged below the canvas 11, the nozzles 28, 29 of each carriage remaining oriented towards said canvas.

A method of operating the installation 10, shown in figure 1 , will now be described. The different steps of said method are executed by program 71.

In a first step, a screening of materials placed on the canvas 11 is carried out. The canvas 11 is set in motion by the device 72. During this step, the carriage 15 is preferably in a housing located at one end of the rails 18, 19.

At the end of the screening step, the device 72 stops working and the canvas 11 comes to a stop. The program 71 then performs a step of unclogging the fabric 11. The compressor 75 is started to supply the channels 48, 49 with compressed air. Preferably, the supply pressure is about 5 bars.

At the same time, the motor 73 is started to move the carriage 15 along the rails 18, 19. By way of example, the speed of movement of the carriage 15 is 25 mm / s.

The side face 40 of each of the collectors 32, 33 slides along the wall 58 of each of the channels 48, 49. When a tab 45 located at the front of a collector comes into contact with a ball 60 of a valve 50, the oblique ramp 47 progressively pushes the ball 60 towards the inside of the channel 48 or 49. The orifice 57 is thus open when it is opposite the orifice 41 of the inlet d air from manifold 32 or 33.

The flow of compressed air passing through the channels 48, 49 thus reaches the collectors 32, 33. Through the inlet openings 36, 37, 44, the compressed air passes through the conduits 24, 25 and arrives at the nozzles 28, 29 The nozzles 28, 29 thus project jets of compressed air in the direction of the fabric 11 in order to unclog said fabric.

During the passage of the face 40 of the manifold in contact with the valve 50, the ball 60 rolls on the blade 42 separating the slots forming the orifice 41. The blade 42 thus maintains the valve 50 in the open position.

When a rear end of the face 40 reaches the level of the valve 50, the ball 60 comes into contact with the oblique ramp 47 of the rear leg 46. The inclination of the ramp 47 gradually releases the pressure on the spring 53, bringing the plug 56 back into contact with the orifice 57. When the carriage 15 moves away from the valve 50, the latter has therefore returned to a closed position.

Preferably, the distance 51 between two valves 50 is less than the length 52 of the inlet 41 of the manifolds 32, 33. Thus, said manifolds are always in contact with an open orifice 57 and the compressed air supply. of the nozzles 28, 29 is continuous during the movement of the carriage 15.

During the unclogging step, the carriage 15 runs the entire length of the rails 18, 19 while the nozzles 28, 29 blow jets of compressed air. At the end of the unclogging step, the compressed air supply is interrupted and the carriage 15 runs along the rails 18, 19 in the opposite direction to reach its housing.

According to one variant, the compressed air supply is maintained during the travel of the carriage in the opposite direction, in order to double the duration of the unclogging step.

According to another variant, the program 71 provides for several round trips of the carriage 15 on the rails 18, 19 in order to extend the duration of the unclogging step.

In the case where the installation 10 comprises two cleaning devices 13, one being above and the other being below the canvas 11, each of the carriages 15 operates according to a method similar to that described above. . According to a first variant, the two carriages 15 move vis-à-vis one another relative to the canvas 11. According to a second variant, the carriages are set in motion in an offset manner.

Claims (9)

1. A device (13) for cleaning a screen (11), of the type comprising blowing means, including:

   - at least two fixed rails (18, 19) intended to be arranged near the screen, respectively along first and second parallel axes (22, 23); and

   - a mobile blowing carriage (15);

   said carriage comprising:

   - a frame (16) provided with means (20, 73) for moving along the fixed rails; and

   - blowing nozzles (28, 29) connected to compressed air supply means (32, 33, 48, 49), said nozzles being intended to be oriented toward the screen,

   characterized in that the compressed air supply means comprise:

   - at least one air supply channel (48, 49), supported by one of the fixed rails (18, 19) and arranged along the first or the second axis (22, 23), and

   - an air collector (32, 33) supported by the frame and connected to the blowing nozzles,

   said fixed rail and the frame comprising passage means (41, 50, 57) for the compressed air between the supply channel and the air collector.
2. The device according to claim 1, such that the passage means for the compressed air between the channel and the collector comprise:

   - an inlet port (41) supported by the air collector and arranged opposite the channel,

   - a valve (50) supported by the channel, said valve being movable between a closed position and an open position, said open position allowing air to pass outside the channel,

   - The passage means (42, 47) for the passage of the valve from a closed position to an open position in contact with the air collector, so as to connect the air supply channel to the inlet port of the collector.
3. The device according to claim 2, such that the channel includes a series of valves (50) distributed over a length of the fixed rail, a distance (51) between two consecutive valves being smaller than the dimension (52) of the inlet orifice along the axis of the rail.
4. A screening installation, comprising:

   - a screen cloth (11) in strip form substantially arranged along a third axis (12),

   - a device (72) for setting the screen cloth in motion,

   - a cleaning device (13) according to one of the preceding claims,

   the third axis being arranged parallel to the first and second axes (22, 23) and the blowing nozzles of the carriage being oriented toward the screen cloth.
5. The installation according to claim 4, comprising a housing located at one end of the fixed rails along the first and the second axes, said housing being able to receive the carriage.
6. The installation according to one of claims 4 to 5, comprising two cleaning devices (13) according to one of claims 1 to 3, said two devices being arranged on either side of the screen cloth.
7. An operating method for a screening installation according to one of claims 4 to 6, comprising the following steps:

   - setting the screen cloth in motion; then

   - immobilizing the screen cloth; then

   - triggering, through said immobilization, the movement of the mobile carriage along the fixed rails and blowing air through the nozzles toward the screen cloth.
8. The operating method according to claim 7 for a screening installation according to claim 6, such that:

   - when the screen cloth is set in motion, the carriage is received in the housing,

   - at the end of the movement of the carriage along the fixed rails, the carriage returns into the housing.
9. The installation according to one of claims 4 to 6, provided with means (70, 71) for implementing a method according to one of claims 7 to 8.

Images