FR3008782A1 - DEVICE FOR PROTECTING AN OPERATION AREA AND CORRESPONDING METHOD - Google Patents

Abstract

The invention relates to a device for protecting an operating zone, particularly for handling products. Said device comprising a plate (2), called diffusion plate, having two opposite faces, one said upper face (202), oriented towards the operating zone (100), and the other, said lower face (200). ). Said diffusion plate (2) comprises a rectifying stage (20), an orientation stage (21) and a diffusion screen (22), said stages each having openings for the passage of a flow of fluid (7) , and each opening of the diffusion screen (22) opening on the upper face (202) of the plate (2) and having a passage section whose surface is smaller than that of each of said openings (215) of the orientation stage (21). The invention also relates to a corresponding method of manipulation.

Description

The present invention generally relates to the protection of a zone of operation. The invention relates more particularly to a device for protecting an operating zone, in particular for handling products, and a corresponding handling method.

In many industrial fields, such as agribusiness, pharmaceuticals, biology or electronics, it is necessary to protect the product handling area from external pollution.

It is known to protect the handling zone by sweeping it by a flow of air. Usually, such an air flow is generated by blowing and / or suction means placed near said handling zone. These blowing / suction means are located near the handling zone to control the flow of air in order to obtain the stability of the airflow with a low speed and a temperature adapted to the comfort of the operators. However, the presence of these blowing / suction means in the vicinity of the operators can be a nuisance for the user by the physical and / or visual size they impose. The operator may also be inconvenienced by the airflow when his face is exposed. The object of the invention is to provide a device for protecting a handling zone, also called the operating field, which makes it possible to improve handling conditions. For this purpose, the subject of the invention is a device for protecting an operating zone, in particular for handling products, said device comprising a plate, called a diffusion plate, having two opposite faces, one of which upper face, oriented towards the operating zone, and the other, said lower face, characterized in that said diffusion plate comprises a first stage, called a righting stage, a second stage, called orientation stage and a third stage, called diffusion screen, said stages each having openings for the passage of a flow of fluid, the openings of the recovery stage emerging on the lower face of the diffusion plate and communicating with the openings of the orientation stage said apertures of the straightening stage being configured to orient the flow of fluid, entering the diffusion plate by its lower face, in a first direction, by vertical example, the openings of the orientation stage communicating with the openings of the diffusion screen, said openings of the orientation stage being configured to orient the flow of fluid leaving the openings of the recovery stage in a second direction oblique with respect to said first direction, each opening of the diffusion screen opening on the upper face of the plate and having a passage section whose surface is smaller than that of each of said openings of the orientation stage. The straightening stage makes it possible to straighten the fluid which arrives at the input of the plate, in particular when it arrives substantially parallel to the plate, that is to say substantially parallel to the underside of the plate. The orientation stage located above, that is to say downstream of the rectifying stage, makes it possible to orient the rectified flow in the desired direction by limiting the pressure losses and the defects of homogeneity of the flow velocity at the plateau diffusion surface relative to a configuration in which the flow would not previously be rectified. The diffusion screen makes it possible, thanks to its reduced openings, to form a substantially flat working surface on which objects can be placed with a reduced risk of falling or jamming in the openings of the tray.

Such a combination makes it possible to direct the flow in an oblique direction relative to the normal to the plate to allow an operator to position himself on the opposite side of the flow in order to limit the exposure of his face to the flow, while limiting the losses. charging the flow and providing a substantially flat handling surface, with a reduced risk of falling object in the openings of the tray. According to an advantageous characteristic of the invention, the thickness of the diffusion screen is smaller than that of the orientation stage or the recovery stage. According to an advantageous characteristic of the invention, the separation zone of the straightening stage and the orientation stage has a part 15 substantially parallel to the upper face of the diffusion plate, situated at the level of the central part of the plateau, and a portion inclined from a low point to a high point away from the center of the plateau relative to the low point. In other words, said high point of the inclined portion is closer to the upper face than to the lower face and is located on the side of the so-called outer slice of the plate at which the operator is positioned. According to an advantageous characteristic of the invention, said device comprises a panel, called a work plane, preferably of thickness substantially equal to that of the diffusion plate, which extends the diffusion plate on the side of a slice, called slice internal, diffusion plateau, opposite the slice, said outer slice, at which an operator is able to position to manipulate products above the diffusion plate, and said second direction corresponding to the orientation of The orientation stage apertures are selected so as to direct the flow of fluid in the upper face of the tray away from the outer edge of the diffusion plate.

According to an advantageous characteristic of the invention, said high point is situated on the or near the upper outer edge of the diffusion plate, defined by the junction of the upper face of the plate and said outer edge. According to an advantageous characteristic of the invention, the orientation stage and / or the recovery stage comprises a honeycomb structure, preferably a honeycomb structure, said cells forming the apertures of said stage. According to an advantageous characteristic of the invention, the cells of the orientation stage are offset with respect to the cells of the recovery stage with which they communicate. A honeycomb structure of the orientation stage and / or the straightening stage makes it possible to contribute to the laminarization of the fluid flow and to guide the flow by limiting the pressure losses, while forming a rigid support for the broadcast screen. Alternatively, the honeycomb structure could be replaced by another honeycomb structure, or other apertured structures, while having like guides to guide flow, such as curved sipes, or bent tubes. Advantageously, the characteristic size of the passage section of each cell, for example the diameter of the inscribed circle, is at least three times smaller than its height. According to an advantageous characteristic of the invention, said diffusion screen is formed by a woven fabric, preferably made of plastic, such as polyethylene. According to an advantageous characteristic of the invention, said device comprises a box having an air inlet and an air outlet opening on the underside of the diffusion plate, and a fan arranged, preferably inside the box. , to circulate a flow of fluid from the inlet to the outlet of said box.

According to an advantageous characteristic of the invention, said device comprises means for regulating the speed of the fluid flow, said speed regulating means comprising a speed sensor and a fan control unit according to the speed of flow of the fluid. fluid acquired by the sensor to maintain the speed of the fluid flow at the output of the diffusion plate substantially equal to a set value. According to an advantageous characteristic of the invention, said speed sensor comprises a housing which extends through a wall of the box and in which are formed a fluid inlet on the side of the interior of the box and a fluid outlet on the side. from the outside of the box, said box housing a probe for acquiring the speed of the flow of fluid flowing between the inlet and the outlet of the box, and said sensor is designed to generate a pressure drop, vis-à-vis fluid passing through it, substantially equal to that generated by the diffusion screen.

According to an advantageous characteristic of the invention, said speed sensor is located between the fan and the air outlet of the box. According to an advantageous characteristic of the invention, said device comprises a filter, called prefilter, located upstream of the fan, preferably at the inlet of said box, and / or a filter, located downstream of the fan, preferably between the fan and speed sensor. According to an advantageous characteristic of the invention, said box is located in the plane passing through the lower face of the diffusion plate. The invention also relates to a method of handling products above a plate, called a diffusion plate, characterized in that said diffusion plate is part of a protection device for an operation zone as described herein. above, and in that an operator is positioned on the side of the plate which is opposite to the direction direction of said fluid flow diffused on the upper face. The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which: FIG. 1 is a sectional view of the device according to the invention showing the flow path of the upstream air downstream of the diffuser plate; FIG. 2 is a schematic view of the speed sensor of the device according to the invention; FIG. 3 is a diagrammatic sectional view of the device according to the invention showing the three stages of the diffusion plate according to the invention. With reference to the figures and as recalled above, the invention relates to a protection device of FIG. an operating zone 100, in particular for handling products of different types. Said device comprises a plate 2, called a diffusion plate, having two opposite faces, one said upper surface 202, oriented towards the operating zone 100, and the other, said lower face 200. Said diffusion plate 2 comprises a first stage, called a righting stage 20, a second stage, called an orientation stage 21 and a third stage, called a diffusion screen 22. Said stages each have openings for the passage of a flow of fluid 7, example of the air. As illustrated in FIG. 3, the openings 205 of the rectifying stage 20 open on the lower face 200 of the diffusion plate 2 and communicate with the openings 215 of the orientation stage 21.

Said openings 205 of the rectifying stage 20 are configured to orient the flow of fluid, entering the diffusion plate 2 by its lower face 200, in a first direction, for example vertical. In the example illustrated in the figures, the axis of each of the openings of the rectifying stage 20 is thus perpendicular to the lower face 200 of the plate. The openings 215 of the orientation stage 21 communicate with the openings of the diffusion screen 22. Preferably, the thickness of the diffusion screen 22 is very small compared to that of the other stages so that the openings of this screen are not shown in the figures. Said openings of the orientation stage 21 are configured to orient the flow of fluid 7, leaving the openings of the recovery stage 20, in a second direction oblique with respect to said first direction.

Thus, to direct the flux diffused by the spreading plate spaced from the operator so as not to interfere, said axis of each opening of the orientation stage 21 is inclined relative to that of each opening of the 20 up stage, so that the opening passages defined by the openings between the lower face 200 and the upper face 202 of the plate 2 each have a bent direction. Each opening of the diffusion screen 22 opens on the upper face 202 of the plate 2 and has a passage section whose surface is smaller than that of each of said openings 215 of the orientation stage 21 as well as that of the openings 205 of the righting stage 20. The term of passage section, the cross section to the axis of the opening. The axis of the opening corresponds to the main direction of the flow flowing through said opening.

Said plate 2 thus has a plurality of through passages allowing a flow of fluid to pass from one face 200 to the other 202 of said plate 2, that is to say allowing the diffusion of a fluid on the side of the upper face of the tray oriented towards the operating zone 100, while straightening the incoming flow on the side of the lower face, then tilting it to diffuse it through the diffusion screen 22 at the operating zone 100 .

The separation zone 201 of the righting stage 20 and of the orientation stage 21 has a portion substantially parallel to the upper face 202 of the diffusion plate 2, located at the central part of the plate, and a part tilted from a low point PB to a high point PH away from the center of the plateau with respect to the low point. As detailed below, the diffusion plate has a side, also called external edge, at which the operator is positioned to handle products on and / or above said plate 2. The inclined portion of the zone of separation extends the parallel part to the outer edge of the plate. Such inclination of the portion of the separation zone 201 between the rectifying stage 20 and the orientation stage 21 situated on the side of the slice 212 of the plate, makes it possible to obtain a diffusion of fluid at the outlet of the plate 2 even close to the operator while maintaining an orientation of the flow in the direction of a spacing relative to the operator. As illustrated in FIG. 3, said high point PH is situated on the or near the upper outer edge of the diffusion plate 2, defined by the junction of the upper face 202 of the plate and of said outer wafer 212.

Said second direction corresponding to the orientation of the openings 215 of the orientation stage 21 is chosen so as to direct the flow of fluid 7 in the upper face 202 of the plate 2 away from the outer edge 212 of the plateau of diffusion 2, to prevent the operator is embarrassed by this flow.

As recalled above, this orientation is achieved by inclination of the flux through the plate 2 of diffusion with respect to its direction of entry into the plate 2 that impresses the rectification stage 20.

As illustrated in FIG. 1 and in FIG. 3, said device comprises a working plane 1, preferably of thickness substantially equal to that of the diffusion plate 2, which extends the diffusion plate 2 at least on the side of the wafer 5 211, called the inner slice, of the diffusion plate 2. Said inner slice is defined in contrast to the external slice 212 at which an operator 9 is able to position itself to manipulate products above the plate 2 diffusion. As illustrated in FIG. 1, provision may be made for the diffusion plate to be positioned in a through opening 10 provided at or near one end of the work plane. As can be seen in Figure 3, each opening of a stage forms, with the openings of the two other stages with which it communicates, a fluid passage conduit. It can be seen that the VF volume of the diffusion plate 2 delimited between the inner wafer 211 and the fluid flow passage ducts which open out into the upper face 202 in the immediate vicinity of the work plane 1, that is to say the side of the inner wafer 211, is closed by the wafer 101 of the worktop 1, so that the VF volume is a "dead" volume which can thus be replaced by a solid material without affecting the diffusion of the flow opposite top of the board. Advantageously, the orientation stage 21 and the rectifying stage 20 each have a honeycomb structure, preferably honeycomb. Said cells then form the openings of said stage. The axis of the cells 25 of the orientation stage 21 is thus inclined relative to that of the cells of the recovery stage 20. It is possible for the cells of the orientation stage 21 to be offset relative to the cells of the rectification stage 20 with which they communicate so as to direct the flow of fluid on the side of the inner wafer 211 of the plate by opposed to the outer edge 212. Advantageously, the structure of each honeycomb is such that the cells are contiguous in a regular polygonal pattern. For example, circular-based cells are contiguous in a hexagonal pattern. The superposition of the two honeycombs may be such that the cells are shifted to the junction, and that the vacuum, that is to say the passage of air, of the cell of the honeycomb meets the full , that is the partition, of the other honeycomb. Thus, in the example illustrated in FIG. 3, it is possible for the rectification stage 20 to comprise a honeycomb with cells of 3 to 6 millimeters in diameter, with a direction orthogonal to the upper face 202 of the plate, and that stage 21 comprises a honeycomb cell 3 to 6 millimeters in diameter, oblique direction at 45 degrees relative to the upper face 202 of the plate. For example, the thickness or height of the diffusion plate is of the order of 50 millimeters.

The offset between the openings of the straightening and orientation stages, in a direction transverse to the normal to the upper or lower face of the plate, makes it possible to redistribute the fluid flow from the straightening stage to the stage. 21 orientation by breaking the boundary layers of the fluid flow. It is also possible to provide a day between the recovery and orientation stages, height corresponding preferably to 10% maximum of the cumulative height of the recovery stages and orientation. Such a day, that is to say a space in a direction substantially parallel to the normal to the upper or lower face of the plate, improves the redistribution of the flux while substantially maintaining the rectified orientation of the flow output of the righting stage. Preferably, said diffusion screen 22 is formed by a woven fabric, preferably made of plastic, such as polyethylene, the meshes of which, for example, have a square shape and a 300 micron side, form said openings of the diffusion screen 22. .

Alternatively, it can be provided that said diffusion screen is formed by a nonwoven web, preferably also plastic, such as polyethylene, pierced to form the openings of said screen. Said plastic may also be polyester or polyamide. However, polyethylene has the advantage of limiting the risk of scratches on objects handled when they are in contact with the screen. Said diffusion screen may also be formed by a pierced film, for example plastic, preferably polyethylene, whose holes form said openings of said diffusion screen. Said diffusion screen may also be formed by a grid or a porous material.

As illustrated in FIG. 1, said device comprises a box 8 having an air inlet 81 and an air outlet 82 opening on the lower face 200 of the diffusion plate 2. A fan 6 is arranged inside the box 8 to circulate a flow of fluid from the inlet 81 to the outlet 82 of said box 8 corresponding to the entrance of the diffusion plate defined by its lower face 200. Said device is equipped with means for regulating the speed of the flow of fluid. Said speed control means comprise a speed sensor, located between the fan 6 and the air outlet 82 of the box 8, and a control unit 61 of the fan 6 as a function of the fluid flow velocity acquired by the sensor 5 to maintain the speed of the fluid flow at the outlet of the diffusion plate 2 substantially equal to a set value despite possible partial closure of the upper surface by the manipulated object and / or by the operator. In addition, said sensor 5 is positioned at a point where the total pressure of the fluid, defined as the sum of the static pressure and the dynamic pressure, is close to that of the fluid just at the outlet of the diffusion plate 2.

Said speed sensor 5 comprises a housing 52 which extends through a wall of the box 8 and in which are provided a fluid inlet 51 on the inside side of the box and an outlet 53 of fluid on the outside side. of the box. Said housing 52 houses a probe 50 for acquiring the speed of the flow of fluid flowing between the inlet and the outlet of the housing 52. Advantageously, the inlet 51 of the sensor is formed by an opening in the housing 52 covered by a screen of the same type, that is to say which has the same aerodynamic characteristics, in particular in terms of pressure drop generated, as that of the screen 22 of diffusion so as to create a pressure drop at the level of sensor input 5 slightly less than that of the plate 2. The pressure drop associated with the plate 2 results not only from the pressure drop associated with the diffusion screen 22 but also from the slight loss of pressure induced by the other stages. 20, 21 of the plate 2. Such a design of the sensor 5 makes it possible to reliably measure a speed of the fluid flow corresponding to a speed that is substantially equal to or slightly greater than that coming from the plate 2.

Said device comprises a filter, called prefilter 30, located upstream of the fan 6, preferably at the inlet of said box. Said device also comprises a filter 31 located downstream of the fan 6, preferably between the fan 6 and the speed sensor 5. Advantageously, the filters are adapted to obtain a class IS05 cleanliness defined in the ISO 14644-1 standard. Advantageously, said box 8 is located under the plane passing through the lower face 200 of the plate 2 of diffusion.

The rear side, opposite to the front side of the plate, delimited by said inner portion 211 of the plate is extended by the work plane 1. Preferably, the upper face 12 of the work plane is flush with the upper face 202 of the diffusion plate.

In the example illustrated in the figures, a portion of said box is located under the plate 2 of diffusion, the other part being located under the plane 1 of work. The disposition of said box to a height less than that of the diffusion plate makes it possible to limit the visual bulk of the operator. Optionally, said device may also be equipped with means for regulating the temperature of the fluid flow.

Such a design of the protective device allows the manipulation of objects supporting a breath of air at 0.6m / s, without detachment of the blower surface, in an atmosphere ensuring a level of cleanliness 1S05.

The manipulated objects can thus be small. The object manipulation on or above the diffusion plate 2 can be carried out without detachment of the latter from the upper face 202, also called the blowing surface, of the plate, under conditions that are comfortable for the operator, by ensuring surface continuity 202 between the blowing surface of the plate 2 and that of the non-blowing plane 1 of the work plane, so as to obtain an assembly formed of the working plane 1 and the plate 2 of diffusion which is free of projecting portion. The device can be easily integrated into an existing workstation thanks to a limited space of the entire device, replacing the portion 20 of the work plane corresponding to the operating field, by the diffusion plate as described above. Such a design of the device according to the invention, and in particular in the case of using regulating means as described above, makes it possible to stabilize the speed of the fluid flow at the exit of the plate. The regulation of the speed of the fluid flow makes it possible to obtain a difference of about 15%, or even less, with respect to the set speed, for a closure of the blowing surface of up to 50%, handling the objects on and / or above said blowing surface. The set speed 30 may be for example 0.45m / s to 20 millimeters downstream of the blower surface.

The present invention is not limited to the embodiments described and shown, but the skilled person will be able to make any variant within his mind.

Claims (15)

REVENDICATIONS1. Device for protecting an operating zone (100), in particular for handling products, said device comprising a plate (2), called a diffusion plate, having two opposite faces, one of said upper face (202), oriented towards the operating zone (100), and the other, said lower face (200), characterized in that said diffusion plate (2) comprises a first stage, called a righting stage (20), a second stage , called the orientation stage (21) and a third stage, called the diffusion screen (22), said stages each having openings for the passage of a flow of fluid (7), the openings (205) of the stage rectifying means (20) opening on the lower face (200) of the diffusion plate (2) and communicating with the apertures (215) of the orientation stage (21), said apertures (205) of the straightening stage (20) being configured to orient the flow of fluid, entering the diffusion plate (2) by its lower face (200), in a first direction, for example vertical, the openings (215) of the orientation stage (21) communicating with the openings of the diffusion screen (22), said openings of the orientation stage (21) being configured to orient the flow of fluid (7) out of the openings of the straightening stage (20) in a second direction oblique to said first direction, each opening of the diffusion screen (22) opening on the upper face (202) of the plate (2) and having a passage section whose surface is smaller than that of each of said apertures (215) of the orientation stage ( 21). 2. Device according to claim 1, characterized in that the thickness of the diffusion screen (22) is smaller than that of the orientation stage (21) or the rectifying stage (20) . 3. Device according to one of the preceding claims, characterized in thatthe separation zone (201) of the rectifying stage (20) and the orientation stage (21) has a portion substantially parallel to the upper face. (202) of the diffusion plate, located at the central portion of the plate, and a portion inclined from a low point (PB) to a high point (PH) away from the center of the plate relative to the low point. 4. Device according to one of the preceding claims, characterized in that said device comprises a panel, called work plane (1), preferably of substantially equal thickness to that of the plate (2) of diffusion, which extends the plateau (2) of diffusion on the side of a wafer (211), said inner wafer, of the plateau (2) of diffusion, opposed to the wafer (212) said outer wafer at which an operator (9) is able to positioning to manipulate products above the diffusion plate (2), and in that said second direction corresponding to the orientation of the apertures (215) of the orientation stage (21) is selected so as to directing the fluid flow (7) on the upper face (202) of the plate (2) away from the outer edge (212) of the diffusion plate (2). 5. Device according to the combination of claims 3 or 4, characterized in that said high point (PH) is located on the or near the upper outer edge of the diffusion plate (2), defined by the junction of the upper face (202) of the tray and said outer wafer (212). 6. Device according to one of the preceding claims, characterized in that the orientation stage (21) and / or the straightening stage (20) comprises a honeycomb structure, preferably honeycomb, said cavities forming the openings of said stage. 7. Device according to claim 6, characterized in that the cells of the orientation stage (21) are offset relative to the cells of the stage (20) of rectification with which they communicate. 8. Device according to one of the preceding claims, characterized in that said screen (22) of diffusion is formed by a woven fabric, preferably plastic, such as polyethylene, 9. Device according to one of the preceding claims, characterized in that said device comprises a box (8) having an air inlet (81) and an air outlet (82) opening on the underside (200) of the diffusion plate (2), and a fan (6) arranged, preferably inside the box (8), for circulating a fluid flow (7) from the inlet to the outlet of said box (8). 10. Device according to claim 9, characterized in that said device comprises means for regulating the speed of the fluid flow, said speed regulating means comprising a sensor (5) speed and a control unit (61) of the fan (6) as a function of the fluid flow velocity acquired by the sensor (5) to maintain the velocity of the fluid flow at the outlet of the diffusion tray (2) substantially equal to a set value. 11. Device according to claim 10, characterized in that said speed sensor (5) comprises a housing (52) which extends through a wall of the box (8) and in which are provided an inlet (51) of fluid on the inside side of the box and an outlet (53) of fluid on the outside of the box, said box (52) housing a probe (50) for acquiring the speed of the flow of fluid flowing between the input and output of the housing (52), and in that said sensor (5) is designed to generate a pressure drop, vis-a-vis the fluid flowing through it, substantially equal to that generated by the screen ( 22). 12. Device according to one of claims 10 and 11, characterized in that said sensor (5) speed is located between the fan (6) and the air outlet (82) 30 of the box (8). 13. Device according to one of claims 9 to 12, characterized in that saiddispositif comprises a filter, called prefilter (30), located upstream of the fan (6), preferably at the inlet of said box, and / or a filter (31) located downstream of the fan (6), preferably between the fan (6) and the speed sensor (5). 14. Device according to one of claims 9 to 13, characterized in that said box (8) is located in the plane passing through the lower face (200) of the plate (2) of diffusion. 15. A method of handling products above a tray, called a diffusion plate, characterized in that said diffusion plate is part of a protection device for an operation zone (100) in accordance with one of of the preceding claims, and in that an operator is positioned on the side of the plate which is opposite to the direction direction of said fluid flow diffused on the upper face.