KR20000010640A - Fiber sheath for ventilating and laminar-flow hood - Google Patents

Abstract

PURPOSE: A fiber sheath is provided to closely protect the sensitive products by the sterilized air flow, particularly the diffusion to the vertical direction when transferring the products. CONSTITUTION: The fiber sheath(1) accepting a duct(9) for feeding the sterilized air is composed of:an impermeable wall(2) made with the impermeable fiber or the fiber constituted with the plastic film forming a part of the outer circumference; a porous wall(3) fed to a diffusion bag(4) of the vertical direction; an outer wall(5) having a porous central area(8) neighboring to two side strips(6) fixed on the end part of the vertical direction of the impermeable wall(2) and two side slots(7) neighboring to the impermeable side strip(6); the sheath(1) placed on the upper area of a conveyer(18).

Description

Ventilated fiber jacket and laminar flow hood

The problem of protecting workplaces from air pollution is particularly important in the agricultural food industry, pharmaceutical industry or hospital environment.

In general, to solve this type of problem, the workplace is located in a so-called "clean room" which filters and processes the air so that the amount of dust is below the controlled permissible threshold under strict standards.

In addition, the air circulating in such clean rooms is often controlled at low temperatures.

Employees working in such workplaces should wear their own attire, which is cumbersome.

Hermetic protection of each individual workplace is one way to solve the above problems.

However, this method of airtight protection should take into account the fact that the products handled by employees working in such workplaces are sensitive to air pollution.

Likewise, it is not desirable to provide a mechanical protection system, for example a door, because its opening and closing operation causes undesired flow disturbances to maintain sterile conditions. For this reason, a means of limiting and maintaining a sterile atmosphere using only a stream of air has been described.

Thus, limiting devices have been developed to ensure a constant volume of hermetic protection with the aid of the vertical flow of air, which diffuses at low speeds, which are two faster air constituting external means of protecting the volume. Adjacent to the injection.

This type of hermetic protection can be implemented in various embodiments, in particular there is a boxed system with a diffusion grill which allows for the generation of a suitable velocity of air flow. Such a system is described in US Pat. No. 3,776,121, which includes a perforated air outlet plate whose surface area is increasing from the center to the outer periphery, so that the slow-diffusing air stream is adjacent to the fast-flowing air stream. This is generated in the central area.

However, this is a fairly heavy device, expensive and above all, not only is it very difficult to clean, but also inflexible, especially if one wishes to provide hermetic protection for the transport duct along the corrugated path.

In general, the present invention relates to the close protection of a workplace located in a contaminated atmosphere, and more particularly to a device for the tight protection of a product sensitive to contamination by airborne contaminants, wherein the product is placed on a work surface. Is located.

The present invention more particularly relates to sheaths for hermetically protecting the transport of sensitive products by the flow of sterile air, in particular in the vertical direction, the sheath extending longitudinally parallel to the sheath axis. Being made of an impermeable wall and a porous wall, the shell forming a sterile air supply duct.

The present invention also relates to a washable or disposable laminar-flow hood and a device for hermetic protection of a wide working surface comprising said sheath.

Hereinafter, the present invention will be described with reference to the following description and attached drawings.

1 is a cross-sectional view of a first embodiment according to the present invention.

2 is a sectional view of a second embodiment according to the present invention.

3 is a sectional view of a third embodiment according to the present invention.

4 is a side schematic view of an embodiment of a device having a plurality of envelopes according to the present invention.

5 is a front schematic view of the apparatus of FIG.

Figure 6 is a front schematic view of another embodiment of a device having a plurality of envelopes according to the present invention.

For this reason, the present invention proposes a hermetic protection device using one or more fiber sheaths capable of generating a certain gas flow. The present invention is in principle capable of making such a device by means of a fiber sheath comprising two central slots adjacent to each other in the longitudinal direction on each side.

Indeed, the Applicant is concerned with two slots each having a width of 15 mm (ie 0.016% of the outer periphery for two slots) and 25% of the outer periphery (ie 0.47 m), for example. It has been found that a 1.885 m outer periphery of the central perforation provides some useful results, but does not provide optimal results. The reason is that the angular velocity of the fast and slow air flow is not constant along the skin.

It is also possible to increase the pressure level inside the shell. However, this may result in the speed in the slot becoming too high. Indeed, the difference in response between the porous fiber and the longitudinal slot makes it impossible to achieve satisfactory results over long lengths.

Finally, French Patent No. 2,124,780 discloses a device comprising a sterile air diffuser tube made of a porous fibrous material, but such a device diffuses high speed sterile air from each side to the side with low speed sterile air diffused from the center. Does not provide a flow.

One of the objectives of the present invention is to solve the above-mentioned problems and to produce a shell so that it can be diffused into a stream of sterile air that is slow at the center and at the high speed on the side.

In general, it will be understood below that the fiber sheath refers to a hose having an arbitrary cross section and mostly consisting of fibers. The skin according to the invention may comprise a part made of plastic, in particular a semi-rigid part.

FIELD OF THE INVENTION The present invention relates to an envelope for hermetic protection of sensitive product transport by sterile air flow, in particular diffusion in approximately a vertical direction, the envelope comprising an impermeable wall and a porous wall extending longitudinally parallel to the axis of the envelope. Wherein the sheath forms a sterile air duct and comprises means for providing a flow extending longitudinally along the porous wall and in which sterile air diffuses centrally at low speed and at high speed on its side. It is done.

Preferably, the width of the total flow is approximately equal to the diameter of the shell, and the rapid flow is approximately tangential to the end of the diameter and is perpendicular to the diameter as with the slow flow.

Preferably, when the air pressure in the duct is 25 to 1000 kPa, the median or slow diffusion rate is 0.2 to 1 kPa and the lateral or high speed diffusion rate is 0.5 to 5 kPa.

According to a first embodiment, the means is a longitudinally extending diffusion bag which is connected to a duct of the outer shell for transporting sterile air through the porous wall and to the porous outer wall where the flow of sterile air is diffused. Closed by The porous wall preferably occupies 25-50% of the outer circumference of the shell.

Preferably, the outer wall of the diffusion bag comprises two impermeable side strips fixed at the ends of the impermeable wall and a porous central region adjacent the two side slots adjacent the side strips. It is useful for the ratio of the porous central region to the slot to be between 10 and 100.

In general, the resistance to air passage of the porous wall is high enough so that the speed of the air passing through to supply the diffuser bag can be achieved consistently in the longitudinal direction, preferably.

According to a second embodiment, the fibrous sheath is formed of an impermeable upper half sheath and a porous lower half sheath, and the longitudinal ends of the impermeable half sheath are each extended by a tangential skirt.

These skirts are the same length.

According to another embodiment, the length of these skirts is different. In this case, access to the protected area is preferably made from the side with a short skirt. Sheaths of this type can also be used to form means to protect a limited volume. This is because if the sheath thus formed is defined at the end by a plane perpendicular to the axis of the fiber sheath, a conventional laminar flow hood is achieved, most of which is washable.

In another aspect, the present invention proposes a device for hermetic protection of a wide working surface, the upper surface of the working surface, a plurality of shells arranged in parallel in a direction parallel to the direction of the transverse end of the working surface, each shell Is formed by an impermeable upper half sheath and a porous lower half sheath to form a sterile air supply duct, located at the same height as the longitudinal end of the working surface and positioned at both edges in a parallel arrangement. The outer longitudinal end of the permeable upper half sheath is extended by a tangential skirt.

Thus, the device according to the invention can protect a wide working surface by a sterile air stream that diffuses faster in terms of lateral air and a central flow of sterile air that diffuses at lower speeds, the diffusion of sterile air being approximately at the working surface. In a vertical direction. The installation cost of such a device is much lower, about six times that of a conventional box device.

In addition, the device with the fiber sheath according to the invention is useful because it can be cleaned by simply separating the sheath since the sterile air source of the sheath is positioned away from the sheath. Therefore, it is not necessary to involve the interruption of the supply when separating the shell. Alternatively, existing devices that include an air supply fan with a prefilter installed upstream and a terminal filter installed downstream are not removable.

In addition, the device having a fiber shell according to the present invention is very useful because it can distribute sterile air over the working surface at a controlled temperature and relative humidity.

According to a first embodiment of the device according to the invention shown in FIG. 1, the fiber envelope 1 containing the duct 9 to which sterile air is supplied is made of an "impermeable or plastic film" which forms part of the outer periphery. An impermeable wall 2 made of “fiber” and a porous wall 3 fed to the longitudinal diffusion bag 4, the outer wall 5 being fixed to the longitudinal end of the impermeable wall 2. Two side strips 6 and two side slots 7 adjacent to the impermeable side strip 6 and a porous central region 8 adjacent thereto. The envelope is located above the conveyor 18.

The diffuser bag thus formed eliminates the inhibition of longitudinal distribution.

In the outer shell having a diameter of 600 mm, i.e., the outer circumference of 1.885 m, the porous portion 3 occupies 25% of the outer circumference, that is, 0.47 m arc. The slot has a width of 5 to 10 mm and the width of the porous central region 8 is 300 mm.

Devices fabricated in this way can provide slow diffusion through the central area, with fast flow spreading on both sides of this diffusion.

According to the second embodiment shown in FIG. 2, the sheath 10 is formed by a porous lower half sheath 12. The outer perimeter is also 1.885 m. The longitudinal ends 13 of the impervious half-side shell 11 each extend tangentially by the skirt 12, with the two skirts having the same length.

Since the semicircle arc (half shell 12) is porous, the flow along the vertical projection is equal to the velocity profile shown by reference numeral 15.

According to FIG. 3, two skirts 16 and 17 of different lengths are connected to the same sheath as in FIG. Defined by a plane (not shown) perpendicular to the axis of the fiber sheath at each end, the device becomes an existing laminar flow hood that can be cleaned or discarded after use.

In the absence of slots, the porous fiber is chosen to be resistant to air passage so that a good longitudinal distribution can be achieved.

The skirt can be made of fiber or plastic film, with each skirt reliably draped by stainless steel rods placed on the lower head (not shown).

The speed achievable by the device according to the invention is between 0.2 and 1 kPa in the central (low speed) region and between 0.5 and 5 kPa in the high velocity flow, when the air pressure is 25 to 1000 kPa.

4 and 5 show a device for hermetic protection of a wide working surface 18.

Here, the useful width l of the working surface 18 is about 1.20 m.

The apparatus comprises a plurality of fiber shells 10 arranged in parallel in a direction X parallel to the direction of the transverse end 18a of the working surface 18, on top of the working surface 18. do. In this case, three shells 10 are provided to cover the entire useful width of the working surface.

Of course, for a wider width, three or more sheaths in the device according to the invention may be arranged in parallel in a direction X parallel to the end 18a of the work.

Each shell 10 is formed of an impermeable upper half side shell 11 and a porous lower half side shell to form a tubular sterile air supply duct 9 in the longitudinal axis X '.

The fibers used to make the impermeable upper half sheath are polyester fibers having a mesh opening pore size of, for example, 5-10 μm. The fibers used for the porous lower half sheath are, for example, polyester fibers having a mesh opening pore size of 15 to 30 μm.

The sheath 10 extends longitudinally parallel to the longitudinal end 18b of the working surface, over the entire length of the working surface (in this case 3.50 m).

As shown in Figures 4 and 5, the impermeable upper half shell of each shell 10 located at the same height as the longitudinal end 18b of the working surface 18 and located at both edges in a parallel arrangement. The outer longitudinal end of 11 is extended by a tangential skirt 14. The two skirts 14 located at each edge in a parallel arrangement extend approximately perpendicular to the working surface 18. According to the embodiment shown in more detail in FIG. 5, the two skirts 14 have the same length, where the length h 'of the skirt 14 is a working surface 18 taken perpendicular to the working surface. ) And approximately the height h between the central axis X of the shell 10.

Of course, according to another embodiment shown in more detail in Figure 6, a skirt having a different length may be provided. In this case, the skirt 16 is shorter in length than the skirt 17 and is approximately equal to 50% of the height h between the working surface 18 and the axis X of the shell 10. Extends by).

More generally, the length of the skirt is 50% to 100% of the height between the working surface and the central axis of the shell.

These skirts can be made of plastic and preferably made of transparent plastic so that an operator located on one side of the device can visually inspect what is happening on the working surface.

The fact that the skirt 16 has a length h " shorter than the height between the central axis of the shell and the work surface is useful because it allows the operator to perform manual work on the work surface.

As shown in FIGS. 4 to 6, the shell is a structural tube of the device by means of a vertical suspension support 3, in the figure three vertical suspension supports 3 which are constantly arranged along the entire length of the shell 10. From 2) is suspended. The shell 10 is supplied with sterile air through the supply duct 1 'by the supply device 1, and the air pressure in each duct 9 of each shell is 25 to 1000 kPa.

Therefore, the velocity profile of the sterilized air emanating from the apparatus shown in Figs. 4 to 6 shows that the diffusion rate of the relatively slow central sterilized air is 0.2 to 1 kPa, and the diffusion rate of the faster side sterilized air is higher. It is supposed to be 0.5-5 kPa.

According to the useful properties of the device for protecting a large work surface, a taut porous flexible ceiling (not shown) can be provided just below the shell over the entire width of the work surface. This is particularly useful for damping a slight increase in the rate of air diffusion at the seam between two successive sheaths and for achieving a flat diffusion rate profile at the center of the working surface.

Such a taut flexible ceiling limits the transverse end effect and reduces head loss in embodiments where the two transverse end sides of the device are closed by a skirt of the type located on the longitudinal end of the outer sheath. It can be usefully used. The use of such a taut flexible ceiling under the sheath allows for optimal control of the flow of sterile air emanating from the sheath.

Several air sampling points are provided at various points above the working surface of the apparatus shown in FIGS. 4 to 5 to check the air quality. More specifically, air sampling points are provided at 50 mm and 150 mm points from the working surface. By counting the number of contaminants or dust particles with a diameter of 0.5 μm or more, the air above the working surface protected by the device is contained because the air contains less than 100 particles with a large diameter (diameter> 5 μm) per cubic foot. It is to confirm that the quality is good. Thus, air quality is Class 100 in accordance with US FS 209E standards. For comparison, the particle measurement in the ambient air of the room where the working surface is located determines that the ambient air is classified as class 100,000 according to the FS 209E standard, and the number of large contaminant particles per cubic foot is 1000 or more. to be.

Of course, the invention is not limited to the embodiments described and illustrated, but one of ordinary skill in the art will be able to suggest any embodiment of the invention in accordance with the scope of the invention.

Claims (19)

Sterilized air formed by impermeable walls (2) and porous walls (3) extending longitudinally parallel to the sheath axis, for the hermetic protection of the transport of sensitive products by the flow of sterile air, in particular in the vertical direction. An envelope (1) forming a feed duct (9), comprising means (4) extending longitudinally along the porous wall and allowing sterile air to diffuse at low speed in the center and at high speed on its side Outer shell, characterized in that. The shell according to claim 1, wherein the median diffusion rate is 0.2 to 1 kPa and the lateral diffusion rate is 0.5 to 5 kPa when the air pressure in the duct is 25 to 1000 kPa. The flow of sterile air according to claim 1 or 2, wherein the means is a longitudinally extending diffusion bag (4), which is connected to a shell duct (9) which carries sterile air through the porous wall (3). An outer shell, characterized in that it is closed by the diffused porous outer wall (5). 4. The two impermeable side strips (6) fixed to the ends of the impermeable wall (2) and the two side slots (7) adjacent the side strips (1) according to claim 3, A sheath comprising a porous central region (8) adjacent to and. 5. The envelope according to claim 3, wherein the resistance to passage of air in the porous wall is high enough such that the velocity of the passing air is attained with a good longitudinal constant. Shell according to any one of the claims 3 to 5, characterized in that the porous wall (3) accounts for 25% to 50% of the outer periphery of the shell. The shell according to any one of claims 3 to 6, wherein the ratio of the width of the porous central region to the slot is from 10 to 100. 3. An impermeable upper half shell 11 and a porous lower half shell 12, wherein each longitudinal distal end 13 of the impermeable shell 12 is in a tangential direction. The outer skin, characterized in that it is extended by the skirt (14). 10. The envelope of claim 8, wherein the skirts are the same length. Shell according to claim 8, characterized in that the skirts (16, 17) are of different lengths. Shell according to any of the preceding claims, which is made of fibrous material. A laminar flow hood, in particular made of fibers, characterized in that it is formed by the sheath according to claim 10 or 11 and is closed at two ends by a plane perpendicular to the axis of the fiber sheath. In the apparatus for hermetic protection of the wide working surface 18, a plurality of parallel arranged in the direction parallel to the direction of the transverse end 18a of the working surface 18, on top of the working surface 18 A shell 10, each shell 10 being formed by an impermeable upper half shell 11 and a porous lower half shell 12 to form a sterile air supply duct 9, The outer longitudinal distal end 11a of the impermeable upper half shell 11 of each shell 10 located at the same height as the longitudinal end 18a of 18) and located at both edges in a parallel arrangement is tangential. Device characterized in that it is extended by a skirt (14) in the direction. 14. Device according to claim 13, characterized in that the envelopes (10) are adjacent in succession. 15. The method according to claim 13 or 14, wherein the low speed central sterilization air diffusion rate is 0.2 to 1 kPa and the high speed side sterilization air diffusion rate is 0.5 to 5 kPa when the air pressure in each duct is 25 to 1000 kPa. Device. The device according to claim 13, wherein the skirts are the same length. The device according to claim 13, wherein the skirts are different in length. 18. The method according to claim 16 or 17, characterized in that the length of the skirts 14, 16, 17 is between 50% and 100% of the distance between the working surface 18 and the central axis X of the shell 10. Device. 19. The device according to any one of claims 13 to 18, wherein a taut porous flexible ceiling is provided just below the shell over the entire width of the working surface.