Allergen exposure system comprising a chamber for mixing air and allergens, which is separated from the exposure room that accommodates the patients

Abstract

An allergen exposure system includes a mixing chamber, delimited by walls and distinct from the air inlet duct and from the exposure room in which the patients are situated. A mixing between a stream of allergen particles from an allergen injection device and a flow of air devoid of allergens which has passed through a filtration device, occurs through a phenomenon of microturbulence in this mixing chamber which forms a widening with respect to the air inlet duct and makes it possible to obtain a flow of air laden with allergen particles which is injected into the exposure room through at least one diffusion outlet so that it can be inhaled by the patients. This invention is of benefit to medical and pharmaceutical research in the field of allergy study.

Claims

1. An allergen exposure system comprising: an allergen injection device comprising a capillary wave atomizer producing a nebulisate flow of allergen particles; an air inlet duct; an exposure room containing air containing allergen particles obtained by mixing a nebulisate flow of allergen particles from the allergen injection device and a flow of air devoid of allergens fed in through the air inlet duct, this exposure room being designed to accommodate patients inhaling the air containing allergen particles to cause an allergic provocation; a mixing chamber, contained by walls, and separated by the walls from each of the air inlet duct, the allergen injection device, and the exposure room such that each of the air inlet duct, the allergen injection device, and the exposure room is on an opposite side of one of the walls with the mixing chamber, in which mixing chamber occurs a mixture between the flow of allergen particles and the flow of air devoid of allergens; the mixing chamber comprises: at least one allergen inlet, configured as a first opening in one of said walls, said first opening providing fluid communication between the mixing chamber and an outlet of the allergen injection device and through which the flow of allergen particles penetrates; at least one air inlet, configured as a second opening in one of said walls, said second opening providing fluid communication between the mixing chamber and connected to the air inlet duct and through which the flow of air devoid of allergens penetrates; at least one diffusion outlet, configured as a third opening in one of said walls, said third opening providing fluid communication between the mixing chamber and the exposure room and through which a flow of air containing allergen particles, obtained by mixing in the mixing chamber the flow of air devoid of allergens and the flow of allergen particles, escapes into toward the exposure room; wherein a first area immediately upstream of the air inlet has a first dimension and a second area immediately downstream of the air inlet, in the mixing chamber, has a second dimension greater than the first dimension, causing an expansion of the flow of air devoid of allergens as the flow of air devoid of allergens enters the chamber, and wherein the allergen inlet is situated in the second area.

2. An allergen exposure system according to claim 1, wherein, at an end of the mixing chamber proximate to the diffusion outlet, the section of the mixing chamber decreases to form a narrowing.

3. An allergen exposure system according to claim 1, wherein the at least one diffusion outlet is an opening made in a wall of said walls of the mixing chamber opening out into the exposure room or into an open duct extending from mixing chamber to exposure room.

4. An allergen exposure system according to claim 1, wherein the mixing chamber comprises a gradual narrowing followed by a gradual widening of its width, thus forming a throttle zone in which there is the at least one allergen inlet.

5. An allergen exposure system according to claim 1, wherein air entering the mixing chamber is devoid of allergens other than allergens deliberately introduced through the at least one allergen inlet.

6. An allergen exposure system comprising: an allergen injection device comprising a capillary wave atomizer producing a nebulisate flow of allergen particles; an air inlet duct; an exposure room containing air containing allergen particles obtained by mixing a nebulisate flow of allergen particles from the allergen injection device and a flow of air devoid of allergens fed in through the air inlet duct, this exposure room being designed to accommodate patients inhaling the air containing allergen particles to cause an allergic provocation; a mixing chamber, contained by walls, and separated by the walls from each of the air inlet duct and the exposure room, in which mixing chamber occurs a mixture between the flow of allergen particles and the flow of air devoid of allergens; the mixing chamber comprises: at least one allergen inlet, configured as a first opening in one of said walls, said first opening providing fluid communication between the mixing chamber and an outlet of the allergen injection device and through which the flow of allergen particles penetrates; at least one air inlet, configured as a second opening in one of said walls, said second opening providing fluid communication between the mixing chamber and connected to the air inlet duct and through which the flow of air devoid of allergens penetrates; at least one diffusion outlet, configured as a third opening in one of said walls, said third opening providing fluid communication between the mixing chamber and the exposure room and through which a flow of air containing allergen particles, obtained by mixing in the mixing chamber the flow of air devoid of allergens and the flow of allergen particles, escapes into the exposure room; wherein a first area immediately upstream of the air inlet has a first dimension and a second area immediately downstream of the air inlet, in the mixing chamber, has a second dimension greater than the first dimension, causing an expansion of the flow of air devoid of allergens as the flow of air devoid of allergens enters the chamber, and wherein the allergen inlet is situated in the second area, at an entrance of the second area, and the allergen inlet is adjacent to the air inlet, and mixing between the flow of air devoid of allergens coming from the air inlet opening and the allergen particle flow coming from the allergen inlet occurs at the entrance of the second area, adjacent to the air inlet.

7. An allergen exposure system according to claim 6, wherein at least one allergen inlet and at least one air inlet of the mixing chamber are arranged with respect to one another so that the flow of air devoid of allergens penetrating into the mixing chamber through at least one air inlet sweeps said at least one allergen inlet opening to carry the flow of allergen particles that penetrates into the mixing chamber through said at least one allergen inlet.

8. An allergen exposure system according to claim 6, wherein the at least one allergen inlet and the at least one air inlet of the mixing chamber are arranged proximate to one another and substantially perpendicularly with respect to each other.

9. An allergen exposure system according to claim 6, wherein the at least one allergen inlet is connected to the outlet of the allergen injection device directly or by a short straight duct.

10. An allergen exposure system according to claim 6, wherein the at least one allergen inlet is a set of one or several simple openings.

11. An allergen exposure system according to claim 1, wherein the allergen exposure system also includes a filtration device arranged at the at least one air inlet or is interposed between the at least one air inlet and the air inlet duct or is placed in the air inlet duct.

12. An allergen exposure system according to claim 6, wherein the at least one diffusion outlet is provided with a grille for directing or adjusting the flow of air containing the allergen particles.

13. An allergen exposure system according to claim 6, wherein the mixing chamber comprises fins, ribs, walls, baffles or channeling or deviating means, for directing flows inside the mixing chamber.

14. An allergen exposure system according to claim 6, wherein the mixing chamber contains at least one temperature, pressure, or humidity sensor.

15. An allergen exposure system according to claim 6, wherein the walls of the mixing chamber are made of a material which does not release particles or releases few particles.

16. An allergen exposure system according to claim 6, wherein the mixing chamber is situated at least partially above the exposure room.

17. An allergen exposure system according to claim 6, wherein, at an end of the mixing chamber proximate to the diffusion outlet, the section of the mixing chamber decreases to form a narrowing.

18. An allergen exposure system according to claim 6, wherein the at least one diffusion outlet is an opening made in a wall of said walls of the mixing chamber opening out into the exposure room or into an open duct extending from mixing chamber to exposure room.

19. An allergen exposure system according to claim 6, wherein the mixing chamber comprises a gradual narrowing followed by a gradual widening of its width, thus forming a throttle zone in which there is the at least one allergen inlet.

20. An allergen exposure system according to claim 6, wherein air entering the mixing chamber is devoid of allergens other than allergens deliberately introduced through the at least one allergen inlet.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other characteristics and advantages will be revealed by reading the detailed description that follows, referring to the attached illustrations, in which:

(2) FIG. 1 is a general schematic top view of an example of the allergen exposure system;

(3) FIG. 2 is a schematic transverse cross view of an example of the allergen exposure system vention;

(4) FIG. 3 is a schematic cross view of an example of the mixing chamber for an allergen exposure system;

(5) FIG. 4 is a transverse cross view of an example of the mixing chamber and exposure room for an allergen exposure system;

(6) FIG. 5 is a top view of an example of the mixing chamber and exposure room corresponding to that of FIG. 4 for an allergen exposure system, and

(7) FIGS. 6 and 7 are top views of two other examples of the mixing chamber.

DETAILED DESCRIPTION

(8) The allergen exposure system is now described in detail with reference to the FIGS. 1 to 7. The equivalent components shown in the various figures will bear the same numerical references.

(9) FIG. 1 depicts the general plan of an example of the allergen exposure system 1, comprising several rooms.

(10) The allergen exposure system 1 comprises an exposure room 2 designed to accommodate the patients to be observed and in which the controlled allergen content inhalation atmosphere can be produced.

(11) The exposure room 2 is a confined chamber where the ambient pressure is lower than the reference pressure (that of the rooms surrounding the exposure system 1) and than the remainder of the exposure system 1.

(12) The size and shape of the exposure room 2 depend on the system location, the technical requirements to be complied with and what the operators want.

(13) It contains one or several chairs 3 where the patients can sit comfortably for the entire exposure period. As a non-limitative example, the exposure room 2 shown in FIG. 1 comprises twenty chairs 3 set out in groups of two throughout the room while the room shown in FIG. 5 is smaller, comprising only six chairs 3.

(14) An entrance airlock 4 and an exit airlock 5, at a higher pressure than the exposure room 2 and the outside, enables the patients to enter and exit the exposure room 2 without any contamination by allergens outside the allergen exposure system 1. These airlocks 4 and 5 also prevent outside pollutants (other allergens, chemical compounds) from entering into the exposure room 2.

(15) A control room 6, also at a higher pressure than exposure room 2 and the outside, enables operators to enter and adjust or check the various experiment parameters and monitor the patients occupying exposure room 2.

(16) The allergen composition intended to be inhaled by the patients is prepared, for instance, in a laboratory 7 equipped for its preparation while offering the technicians and patients total safety. The composition is then placed in an allergen injection device 8 which feeds it into a mixing chamber 9, not shown in the FIG. 1, but which will be extensively described below, with reference to the following figures.

(17) The allergen exposure system 1 may also comprise a technical room 10 containing, for instance the devices 11 required for ventilation, humidification, air-conditioning and/or heating the various rooms of the allergen exposure system 1 or any other apparatus or bulky equipment required for the operation of system 1.

(18) The system can be completed by a reception and waiting room 12 for the patients.

(19) According to the described embodiments, the allergen exposure system 1 comprises a mixing chamber 9 of which several examples are shown in the FIGS. 2 to 7.

(20) It concerns a hollow volume, contained by walls 13 forming a box, which is distinct and separate from the exposure room 2 and also distinct and separate from the air inlet duct, in which the allergen particles are mixed with a flow of air devoid of allergens, before being fed into the exposure room 2.

(21) In order not to damage the allergen particles and to facilitate cleaning between two exposure sessions, the walls 13 of mixing chamber 9 are preferentially smooth, without any aggressive protruding parts or sharp angles or corners liable to allow matter accumulation.

(22) Preferably, they will be made of a material which does not release or releases few particles and volatile organic compounds (VOCs), and that are easily cleaned and resist the products used for cleaning (for instance H.sub.2O.sub.2). For the purpose, it would be possible to use, for instance, thermosetting high pressure laminated (HPL) panels, such as compact blocks, for instance, and in particular those sold under the name FUNDERMAX® or ATHLON®. These are a material consisting of paper-based composites impregnated with phenol resin and melamine resin, fireproofed in the mass. For instance, it would also be possible to use an acrylic resin with mineral fillers, in particular as marketed under the names CORIAN®, HI-MAX® or STARON®.

(23) In the patent application, a “material which releases few particles” will be defined as a material releasing a number of particles less than that required to obtain an ISO rating less than or equal to 7 according to standard 14644-1.

(24) The mixing chamber 9 comprises at least one inlet, called the allergen inlet 14, through which the allergen particles to be inhaled by the patients are infed.

(25) This allergen inlet 14 is adapted so as not to degrade the allergens passing through it. It does not comprise nozzles or an aggressive system liable to damage the allergens. In particular, it may be a simple opening 15, for instance circular, as shown in FIGS. 5 and 7.

(26) The allergen inlet 14 is connected to the outlet of the allergen injection device 8, preferably directly as shown, or for instance, by means of a short straight duct.

(27) Naturally, other forms of connection, less favourable to the preservation of the integrity of the allergen particles are possible, in particular a bent or longer inlet duct.

(28) According to another embodiment, the mixing chamber may comprise several allergen inlets 14, for instance in the form of a set of openings 15, substantially aligned like an injection pipe as shown in the example of FIG. 6. Other arrangements of these allergen inlets 14 are obviously possible without moving out of the scope of this described embodiments.

(29) The allergen injection device 8 can be of any type depending on the techniques that the operator wishes to use. It may consist of a pneumatic allergen powder injection device or preferably of an injection device operating from a liquid composition of allergens, such as a spray, an atomizer or a nebulizer, for instance.

(30) In a preferred embodiment, the allergen injection device 8 is a capillary wave atomizer.

(31) In the examples shown, the liquid allergen composition prepared in the laboratory 7 is poured into a tank 16 then fed into the allergen injection device 8 by duct 17. It is then injected into the mixing chamber 9 into which it penetrates through the opening or openings 15 forming the allergen inlet 14 (inlet phenomenon).

(32) In the figures, the flow of allergen particles 18 is symbolized by white arrows. Preferably, it concerns a fine nebulized mist.

(33) The mixing chamber also comprises at least one air inlet 19 through which arrives the air devoid of allergens designed to ventilate the exposure room 2. This flow of air 20, laminar and devoid of allergens, is symbolized in the figures by black arrows with a white tip.

(34) This air inlet 19 is connected to an air inlet duct 21.

(35) Preferably, a filtration device 22 is arranged at the air inlet 19 or interposed between this air inlet 19 and the air inlet duct 21, to prevent any allergens or other unwanted particles, and possibly even some chemical pollutants, present in the air entering through the air inlet duct 21, from penetrating into the mixing chamber 9 and subsequently into the exposure room 2.

(36) The filtration device 22 operates in both directions, guaranteeing among other things that the allergen particles in the mixing chamber 9 are unable to leave via the air inlet duct 21 in the event of the flow of air being cut off. Retro-contamination is thus avoided and the containment of the exposure room 2 is ensured.

(37) The filtration device 22 preferably comprises a high efficiency filtration device, also known as a HEPA filter (High Efficiency Particulate Air filter), or an ultra high efficiency filtration device, known as an ULPA filter (Ultra Low Particulate/Penetration Air filter), as defined in the standard EN 1822-1. Among these, it is advantageous to choose a filter of the H14 type, preferably completed by one or several filters active against VOCs (volatile organic compounds), for instance based on activated carbon, cold plasma, porous ceramics or other means.

(38) An HEPA filter of the H14 type offers the advantage of being an absolute filter which can be qualified prior to the use of the allergen exposure system 1 by an integrity test according to the standard 14644-3.

(39) Preferably, the filtration device 22 has an insertable filter case which is preferably inserted into the air inlet 19 of the mixing chamber 9 and which, for instance, is in the form of a thick plate or a rectangular or round cartridge, or of any other appropriate shape.

(40) According to another non-limitative alternative, the filtration device 22 can also include, instead of or in addition to the insertable case, a filter case in a duct, located inside the air inlet duct 21, although it is less easy for cleaning.

(41) The size of the filtration device 22, in particular the filtering surface, obviously depends on the low rate of the incoming flow of air 20 and therefore on the volume of the exposure room 2 to be a ventilated. Indeed, the flow rate of the flow of air 20 must be proportional to the volume of the exposure room 2 to guarantee a satisfactory mixing level in the exposure room, preferably conforming to the standard 14644-1 so that a particle classification without exposure of ISO8 class can be obtained for the exposure room 2.

(42) For a small exposure room 2 as shown in FIG. 5, a small filtration device 22 will be sufficient whereas a more widely-encompassing filtration device 22, as in the examples of FIGS. 6 and 7, will be necessary for a large exposure room 2, in particular the one shown in FIG. 1.

(43) In the mixing chamber 9, the flow of air 20 entering through the air inlet 19 reaches an inlet zone having a larger section than that of the air inlet duct 21. It thus forms a widening 31 compared to this air inlet duct 21, causing pressure reduction by the expansion of the flow of air 20 devoid of allergens when it enters the chamber. Therefore the speed of the flow of air 20 is slowed down.

(44) The slowed down flow of air 20 then carries the flow of allergen particles 18 which arrives through the allergen inlet(s) 14.

(45) The outlet pressure of the flow of allergen particles 18 is preferably designed to be higher than the outlet pressure of the flow of air 20 to prevent the air from entering into the allergen injection device 8, although the volume of air entering the mixing chamber 9 is however far greater than that of the allergen particles.

(46) Because of the relative disposition of the air inlets 19 and allergen inlets 14, the shape and limited size of the mixing chamber 9, the pressurizing of the mixing chamber 9 by the incoming flow of air 20, and the reduction of the speed of the flow of air 20 at its inlet into the mixing chamber, micro-turbulences 23, symbolized in the figures by small black arrows, are created in this mixing chamber 9. These micro-turbulences allow gentle and satisfactory mixing of the flow of allergen particles 18 with the flow of air 20, without there being any need to add a mixing device, such as a fan or another device.

(47) To improve this mixing even more, several optional arrangements of the mixing chamber can be imagined by a man skilled in the art.

(48) For instance, the relative disposition of the air inlet 19 and the allergen inlet 14 can be chosen so that the flow of air 20 entering the mixing chamber 9 through the air inlet 19 sweeps over the allergen inlet 14 to carry the flow of allergen particles 18 entering mixing chamber 9 through the allergen inlet 14.

(49) According to an embodiment, the air inlet 19 and the allergen inlet 14, for this purpose, are arranged near one another and substantially perpendicular to each other, that is, so that the flow of air 20 and of the allergen particles 18, opening respectively from air inlet 19 and allergen inlet 14, are perpendicular to one another.

(50) In addition, fins 24, ribs, walls, baffles or any other adapted channeling or deviating means can be used for directing the flows into the mixing chamber 9 and included in the mixing chamber 9, for instance at the air inlet 19, to improve the formation of the micro-turbulences. However, these devices are preferably chosen and arranged in such a way as not to damage the allergen particles.

(51) Accordingly, in the embodiment shown in FIG. 7, the side walls 13 of the mixing chamber 9 are curved inwards to form a gradual narrowing, followed by gradual widening of the width of mixing chamber 9, forming a throttle zone in which the allergen inlet 14 is located.

(52) The entire flow of air 20 entering the chamber through the filtration device 22, even if the latter has a large surface area, is thus directed to the allergen inlet 14 passing above opening 15 and carrying with it the flow of allergens 18.

(53) In addition, the successive effect of compression caused by the narrowing, followed by the pressure reduction resulting from the subsequent widening, favours the appearance of micro-turbulences 23 in the second part of the mixing chamber 9, improving the thorough mixing of the air and the allergen particles.

(54) According to the described embodiments, the mixing chamber 9 also includes at least one diffusion outlet 25, connected directly or indirectly to the exposure room 2 and used for feeding into the exposure room 2 a flow of air containing allergen particles 26, obtained after mixing in the mixing chamber 9 of the flow of air 20 with the flow of allergen particles 18.

(55) This diffusion outlet 25 can be a simple opening arranged in wall 13 of the mixing chamber 9, opening out directly into the exposure room 2 or into an open duct extending from the mixing chamber 9 to the exposure room 2 if these two zones are at some distance from each other.

(56) It can also be equipped with a grille 27 or any other appropriate device for directing or adjusting the flow of air containing the allergen particles 26 without breaking or damaging the allergen particles.

(57) The number, size, arrangement and orientation of these diffusion outlets 25 depend on the size, the accommodation capacity and the shape of the exposure room 2. The diffusion outlet(s) 25 is (are) arranged to ensure the homogeneous distribution of the flow of air containing allergen particles 26 throughout the entire exposure room 2, without a preferential direction or privileged zone.

(58) In some embodiments, the section of the mixing chamber 9 may preferably decrease in order to form a narrowing 32 just before the diffusion outlet or outlets 25. The flow of air containing allergen particles 26 is therefore accelerated again before penetrating into the exposure room 2 to improve the carrying of the allergen particles throughout the exposure room.

(59) In the example of the embodiment shown in FIGS. 4 and 5, the mixing chamber 9 is situated in a suspended ceiling, partially over the exposure room 2 and, for instance, the control room 6.

(60) Accordingly, it connects directly with the allergen injection device 8 located in the control room 6 through a circular opening 15, opening into the bottom wall of the mixing chamber 9 and which is used as allergen inlet 14.

(61) The air inlet 19 is arranged in the adjacent rear wall of the chamber 9, near the allergen inlet 14, and is directed substantially perpendicularly to it.

(62) The mixing chamber 9 is separated from the exposure room 2 by three portions of wall 13, inclined and oriented in three different directions, in order to face with all the zones of the exposure room 2. It includes three diffusion outlets 25, each located on one of these portions of wall 13, and each of them being directed towards one of the three groups of chairs 3.

(63) The embodiment shown in FIG. 7 includes four diffusion outlets 25, smaller but oriented in four different directions.

(64) According to the application concerned, the man skilled in the art may freely define the number and arrangements most appropriate for diffusion outlets 25, depending on the geometrical parameters of exposure room 2 to be ventilated to guarantee homogeneous diffusion of the air containing allergens in exposure room 2, without there being a preferential direction.

(65) In a preferred embodiment, the mixing chamber 9 may also contain one or several sensors 29 of any appropriate type, such as, for instance, a temperature, pressure or humidity sensor or a sensor connected to a measuring device 30, used for instance, for measuring the concentration or size of the allergen particles, or any other sensor used for monitoring, controlling or guiding the operation of the allergen exposure system 1.

(66) With the allergen exposure system 1, the mixing between the allergen particles and the ventilation air devoid of allergens is not carried out directly in exposure room 2 nor in the air inlet duct 21 but in the mixing chamber 9 which is a separate and distinct place.

(67) Only the flow of air containing the allergen particles penetrates into exposure room 2. This flow is outstandingly homogeneous and can be controlled at the outlet of the mixing chamber 9 by means of one or several sensors 29.

(68) Thanks to the described embodiments, the flow of air inhaled by the patients in the exposure room has the advantage of being very homogeneous with a substantially constant concentration of allergens, with a tolerance of 20% at the most. Such a result cannot be obtained with any of the systems of the prior art.

(69) Obviously, the present description is not confined to the preferential embodiments described previously and shown in the various figures, a man skilled in the art being able to make many modifications and imagine other variants without moving out of the scope or framework defined by the claims.