Combined access and ventilation system, intended for use in a hazardous area, and hazardous area thus equipped

Abstract

Combined access and ventilation device, intended for use in a hazardous area, and hazardous area thus equipped. This device (I), intended in particular for use in a room (II) of a hospital, comprises a frame (1) mounted on the main frame of the room, which together form a secondary frame defining a secondary opening (2), an opening (3) allowing the secondary opening to be closed, a ventilation unit (4) in the upper part of the frame, comprising high-efficiency air filtration means (53), as well as a suction and supply system. This device, together with the main frame, defines an intermediate air passage (160), in communication with the internal orifice (60) of the ventilation unit.Thus, in a first configuration, air is extracted from the risk zone via successively the intermediate passage (160), the internal orifice (60), and the external orifice (62), and in a second configuration, air is blown into the risk zone via successively the external orifice, the internal orifice, and the intermediate passage. The invention generates minimal impact on civil engineering, allows convenient access to the risk zone, and does not impede the free movement of healthcare personnel and medical equipment within the risk zone itself. Figure 7.

Description

Title of the invention: Combined access and ventilation device for equipping a hazardous area, and hazardous area thus equipped. Technical field of the invention

[0001] The present invention relates to the technical field of so-called risk zones. For the purposes of this invention, these risk zones can, first of all, be rooms that are contaminated, or that are likely to become contaminated. This can arise from the fact that these rooms contain, or will contain, a source of contamination. This source may, in particular, originate from patients who are at least potentially contaminated. The expression "at least potentially contaminated" means that the patients in question are actually contaminated, or present significant suspicions of such contamination. In this case, such risk zones are typically hospital rooms.

[0002] However, the invention also has application to other sources of contamination, which may originate from animals or industrial equipment. The risk zones targeted by the invention may therefore also be the site of contaminating activity, particularly in the sense of nuclear, radiological, chemical, or biological risks to humans.

[0003] In the context of the invention, these risk zones may also be related to the treatment of immunocompromised patients, or those requiring protection from contamination. As with the first situation described above, a risk zone in this case is generally a hospital room intended for the care of such a patient.

[0004] More specifically, the invention relates firstly to a device providing a dual function of access and ventilation, which is suitable for equipping a risk zone as defined above. It also relates to a risk zone equipped with such a combined device. State of the art

[0005] When these risk zones involve potentially infected patients, the standard approach is to create negative pressure in the risk zone relative to its surroundings. Conversely, when the risk zones involve immunocompromised patients, the approach is to create positive pressure in the zone relative to their surroundings. In both cases, healthcare personnel must adhere to strict protective measures.

[0006] When the patient is infected, it is necessary to prevent healthcare personnel from becoming infected and, furthermore, from transmitting the infectious agents to outsiders. On the other hand, when the patient is immune In the absence of depression, healthcare personnel must avoid introducing substances harmful to the patient's immune system from the outside.

[0007] In general, various solutions are proposed in the prior art. These include, in particular, the development of deployable tents that can be set up inside a hospital room. The use of ventilation units equipped with filtration systems is also known. The implementation of deployable airlocks should also be mentioned, although their use is relatively limited.

[0008] These various solutions are not entirely satisfactory. Indeed, they can prove ineffective, in that they carry an unacceptable quantity of contaminants. Furthermore, they can be uncomfortable for the patient, particularly in terms of noise. In addition, they are bulky, which can hinder the efficient use of the room's interior space, affecting the walls, floors, and ceilings. Finally, some of these solutions are not very versatile, as they do not allow for the treatment of both infected and immunocompromised patients.

[0009] Under these conditions, the invention aims to remedy the disadvantages of the prior art, presented above.

[0010] It aims in particular to propose a device which effectively ensures both the depressurization and the overpressure of a risk zone.

[0011] It also aims to propose such a device, which generates a minimal impact on civil engineering.

[0012] It also aims to propose such a device which allows convenient access to the risk area, in particular by delimiting an opening whose dimensions are not such as to impede the passage of healthcare personnel as well as any medical equipment.

[0013] It also aims to propose such a device, which does not hinder the free movement of this healthcare staff and any medical equipment, within the risk zone itself.

[0014] It also aims to propose such a device, which allows for the simple and rapid equipping of at-risk areas, enabling them to accommodate a large number of patients. This need is acutely felt during the emergence of large-scale epidemic phenomena, such as the proliferation of coronaviruses.

[0015] It also aims to offer such a control system, the manufacturing cost of which is reasonable so that it can be installed on a massive scale in the same hospital establishment.

[0016] It aims finally to offer such a control system which provides appreciable comfort to the patient's overall environment, particularly in terms of acoustics. Objects of the invention

[0017] At least one of the above objectives is achieved through a first object of the invention which is a combined access and ventilation device (I) for a risk zone, in particular a room (II) of a hospital establishment, said risk zone comprising enclosure walls forming at least one main frame (140), this frame delimiting a main opening (130)

[0018] said device comprising

[0019] a frame (1) equipped with means (15,16) for mounting on the main frame, this frame forming a so-called secondary frame delimiting a so-called secondary opening (2)

[0020] an opening (3) allowing the selective closing of the secondary opening

[0021] a ventilation unit (4), provided on the upper part of the frame, this unit of ventilation unit being suitable for being fixed to the upper part of the main frame and comprising high-efficiency air filtration means (53, 54), as well as a suction and supply system (55, 56), said ventilation unit further comprising at least one internal opening (60) allowing air circulation between the interior of the risk zone and the ventilation unit, as well as at least one external opening (62) allowing air circulation between the ventilation unit and the exterior of the risk zone

[0022] said device comprising sealing means (81, 82, 83, 84) which are capable of cooperating with the main frame (140)

[0023] said combined device (I) being capable of delimiting, with the main frame, an intermediate air passage (160) communicating in service with the internal orifice (60) of the ventilation unit,

[0024] each ventilation unit being capable of circulating air such that:

[0025] - in a first configuration, air is extracted from outside the risk zone via successively the intermediate passage (160), the internal orifice (60) and the external orifice (62)

[0026] - in a second configuration, air is blown inside the risk zone via successively the external orifice, the internal orifice and the intercalary passage.

[0027] According to other features of the device according to the invention, taken individually or in any technically compatible combination:

[0028] - the internal orifice is formed in the form of a slot (60) formed on a wall front (42) of the ventilation unit, in particular at the lower end of this front wall, said front wall being intended to be applied against the main frame.

[0029] - the height (H60) of said slot is between 10 mm and 150 mm, in particular between 10 mm and 50 mm.

[0030] - the width (L60) of said slot is between 900 mm and 1500 mm, in particular between 1000 mm and 1250 mm.

[0031] - the surface area of ​​the secondary opening (2) is greater than 80%, in particular 90% of the surface of the main opening (130).

[0032] - the upper region of the opening (3) is suitable for delimiting, with the main frame, at least part of the intercalated air passage.

[0033] - the filtration means include at least one high-efficiency filter (53, 54), where the suction and blowing system includes at least one fan (55,56), two filters and two fans are advantageously provided in two separate compartments (51) of the ventilation unit (4).

[0034] - the sealing means include first so-called lateral seals (81,82) in each is able to come against a respective lateral post (142,144) belonging to the frame, each lateral joint being at least partly covered by a respective cover, this cover (17,18) being fixed on a lateral rail (10,11) of the frame and projecting opposite said lateral post.

[0035] - the sealing means include a so-called upper seal (84), fixed to the unit of ventilation so as to come to rest against an upper edge (146) belonging to the frame.

[0036] A second object of the invention is a risk zone, in particular a room (II) of a hospital establishment, said risk zone comprising enclosure walls forming at least one main frame (140), this frame delimiting a main opening (130), said risk zone being equipped with a combined access and ventilation device (I) as above,

[0037] the frame (1) of said combined device being either received at least in part in said main opening, or placed against the outer face of the main frame

[0038] whereas the ventilation unit is placed against the outer face of a so-called upper edge of the main frame, extending above said main opening,

[0039] said combined device (I), in particular the upper region of its opening (3), delimiting, with the main frame, in particular with said upper edge (146), an intermediate air passage (160) which communicates with the internal orifice (60) of the ventilation unit, this intermediate passage being in particular located opposite this internal orifice.

[0040] According to a first feature of the invention, the height (H 160) of the intermediate passage (160) is equal to the height (H60) of the internal orifice (60). Alternatively, this height of the intermediate passage is strictly greater than the height of this internal orifice.

[0041] According to another feature of the invention, the upper part of the opening (3), in in particular its sash (30), delimits at least in part the passage of air between the main frame and the main frame.

[0042] The device according to the invention is intended to functionally replace the existing door to the hazardous area. However, this existing door is generally not removed, but typically retracted along a partition wall. This device is equipped with a ventilation unit, allowing for the alternate pressurization and depressurization of the interior of the area. This ventilation unit is integrated into the frame of the device of the invention, so that it does not significantly encroach on the interior of the hazardous area. Furthermore, the device according to the invention eliminates the need for any equipment, such as tubing, ducting, or the like, inside the hazardous area. This allows for the maintenance of smooth circulation within this hazardous area for healthcare personnel. In addition, there is an acoustic advantage, since the ventilation unit is located on the corridor side.

[0043] Most advantageously, the device according to the invention delimits a shallow intermediate space between the main frame of the hazardous area and the main frame. This intermediate space allows ventilation air to flow both towards the hazardous area in the event of positive pressure, and also away from this area in the event of negative pressure. The device according to the invention therefore ensures convenient access to this hazardous area, since the so-called secondary opening in the aforementioned secondary frame has dimensions close to those of the original main opening. In this way, easy passage between the inside and outside of this hazardous area is ensured.

[0044] The device according to the invention is capable of supplying fresh air to the hazardous area. This function may be supplemented by a specific purification unit of any suitable type, adapted for use in a highly controlled environment in accordance with applicable regulations. This unit will be judiciously positioned so as to minimize disruption to traffic flow in the aforementioned area. For example, this purification unit may be placed on a side wall or at ceiling level in this area. DESCRIPTION OF THE FIGURES

[0045] The invention will be described below, with reference to the accompanying drawings, given solely by way of non-limiting examples, in which:

[0046] [Fig. 1] is a perspective view, illustrating a hospital room, forming a risk zone according to the invention, which is equipped with a combined access and ventilation device according to the invention.

[0047] [Fig.2] is a perspective view, showing the device on a larger scale combined illustrated in [Fig.1], seen from outside the chamber.

[0048] [Fig.3] is a cross-sectional view, along line III-III in [Fig.2].

[0049] [Fig.4] is a cross-sectional view, along line IV-IV in [Fig.2].

[0050] [Fig. 5] is a longitudinal sectional view, illustrating in more detail a unit of ven tilation belonging to the device of the previous figures.

[0051] [Fig.6] is a cross-sectional view, illustrating the ventilation unit of the [Fig.5] , as well as the integration of the device according to the invention in relation to the frame of the room.

[0052] [Fig.7] is a front view, illustrating the ventilation unit seen from inside the chamber, in particular its so-called internal air passage opening.

[0053] [Fig.8] is a schematic front view, illustrating the chamber frame, the main opening of this frame, as well as the secondary frame and the secondary opening delimited by the device according to the invention.

[0054] [Fig.9] is a cross-sectional view, analogous to [Fig.3], illustrating a variant of the design implementation of the device in accordance with the invention.

[0055] [Fig. 10] is a cross-sectional view, similar to [Fig. 6], illustrating the integration of the device in [Fig. 9] with respect to the frame of the room. Detailed description

[0056] As shown in [Fig. 1], the device according to the invention, which is designated as a whole by reference numeral I, is intended to equip a high-risk area as defined above. In the illustrated example, this high-risk area is a room II belonging to a hospital. This room comprises, as is known per se, a floor 110, a ceiling (not shown), a glazed partition 111, and opposing solid partitions 112, 113. Furthermore, an additional partition 114 allows communication between this room II and the corridor, which is designated as a whole by reference numeral III. For this purpose, this partition 114 has a main opening 130, around the periphery of which extends a main frame 140. The room is also equipped with various conventional medical devices, which will not be described in further detail below, such as a bed 115.

[0057] In the embodiment shown in Figures 2 to 8, the device I for controlling the airflow parameters is intended to be inserted into the main opening 130 above. It should be noted that the device is provided in place of the original door, for example, a fire-resistant door, which is retracted along the partition. This device I comprises, firstly, a frame 1, forming a secondary frame. This frame is essentially formed by two lateral rails 10 and 11, which are mutually connected at the top by a ventilation unit that will be described below. A door threshold, not shown, may be provided if necessary, but this is not a limitation.

[0058] This frame 1 defines a central opening 2, called a secondary opening, which can be selectively closed by an opening 3. In the illustrated example, the latter is formed by a single leaf 30, equipped with a handle 32. As an alternative, a double leaf can be used. This leaf 30 is hinged to the frame by any suitable means, in particular via hinges 34 mounted on one of the rails, for example rail 10. The leaf 30 is advantageously transparent, which allows direct visual monitoring of the patient by the healthcare staff.

[0059] The device according to the invention further comprises a ventilation unit, designated as a whole by reference numeral 4, which will be described in more detail with reference to Figures 5 and 7. This unit 4 comprises, firstly, a casing 40, which is, for example, parallelepiped-shaped in the illustrated example. This casing 40 is fixed to the upper part of the frame 1 by any suitable means, in the illustrated example by L-shaped angle brackets 41, provided on each rail as well as on the lower wall of the casing 40 (see in particular [Fig. 2]). However, it may be provided that the casing 40 is fixed directly to the upper edge 146 of the frame.

[0060] This enclosure consists of various walls, namely, firstly, a front wall 42 intended to be attached to the aforementioned upper edge 146. There is also an opposite wall 43, called the rear wall, an upper wall 44, a lower wall 45, visible in particular in [Fig. 7], as well as side walls 46. The enclosure is equipped with a first partition 48, called the transverse partition, which connects the opposite side walls. This partition delimits a channel 49, extending along the lower wall and then the rear wall, which opens into a main enclosure 50. The latter is divided into two compartments 51 by means of an axial partition 52, which connects the opposite front and rear walls.

[0061] Each compartment 51 is first fitted with a respective filter 53, 54, which is a high-efficiency filter, also known as a HEPA (High Efficiency Particulate Air) filter. According to standard EN 1822, this means that 99.95% of particles 0.3 micrometers or smaller are retained by this filter. Each compartment is also fitted with a respective fan 55, 56, of any suitable type. Providing separate compartments, each equipped with its own dedicated fan, helps to reduce noise levels.

[0062] With reference in particular to [Fig. 6], the front wall 42 defines an internal opening 60, which provides communication between the interior of the room and the internal volume of the ventilation unit, in both directions, as will be seen below. Advantageously, this internal opening 60 is formed in the form of a slot located at the lower end of this front wall. For example, the height H60 of this opening is between 10 mm and 150 mm, in particular between 10 mm and 50 mm. Furthermore, this slot, which extends... covered extensively across the entire front wall, has a width L60 between 900 mm and 1500 mm, specifically between 1000 mm and 1250 mm.

[0063] With reference now to Figures 2 and 5, each side wall 46 defines a respective opening, referred to as the external opening 62. This opening ensures communication between the interior volume of the ventilation unit 4 and the exterior of the room, in both directions, as will be seen below. The shape, location, and dimensions of each opening 62 are not essential features of the invention: those skilled in the art can thus choose these parameters appropriately. Typically, the openings 62 are made in the form of a grid.

[0064] Finally, the ventilation unit includes a control (not shown), of any suitable type, which receives information from sensors (also not shown) that measure the pressure, on the one hand, in the room, and on the other hand, in the corridor. The control is capable of triggering an alarm of any suitable type, including visual and / or audible, if the pressure difference between the sensor measurements falls outside a predefined range. Advantageously, the alarm is located outside the room, for example, on the exterior face of the frame. This prevents the alarm from being visible to the patient, which would be detrimental to their physical and psychological well-being.

[0065] In the embodiment shown in Figures 2 to 8, the peripheral dimensions of the frame 1 are slightly smaller than those of the main opening defined above. Consequently, as shown in [Fig. 3], the side rails 10 and 11, as well as the top rail 13, are positioned inside the opening. This frame is fixed to the walls of the fixed frame by any suitable means. In the example illustrated with reference in particular to [Fig. 3], brackets 15 and 16 are used, which allow each rail 10 and 11 to be mounted on a respective upright of the main fixed frame.

[0066] We will now describe the various means that ensure the airtightness of the device according to the invention, namely that they prevent any significant airflow between the inside and outside of the risk zone, apart from the ventilation unit described above. Each rail 10 and 11 is first covered by a respective cover 17 and 18, which protrudes towards the main frame. The protruding part 171, 181 of the cover is fitted with a seal 81, 82, itself fixed against a respective upright 142, 144 belonging to the frame 140.

[0067] Furthermore, in its lower part, the leaf 30 is fitted with a seal 83 of any suitable type, in particular a lip seal. This seal 83 cooperates with the floor of the room so as to prevent any air leakage. In the case not shown where the frame incorporates a door threshold, the latter can act as a stop by being fitted with a seal ensuring airtightness. Finally, the front wall 42 of the ventilation unit 4 receives an additional seal 84, also of any suitable type. This seal 84, which cooperates with the upper edge 146 of the main frame, has for example an inverted U shape as shown in particular in [Fig.7].

[0068] With reference to Figures 7 and 8, which summarize the above explanations, the frame 1 of device I is housed in the main opening 130 made in the frame 140, the walls of which are shown in dashed lines. In contrast, the ventilation unit 4 is surface-mounted against the outer face 147 of the upper edge 146 of the frame. Furthermore, the upper region of the sash 30, together with the edge 146, defines an intermediate passage 160 (see in particular [Fig. 7]). This passage 160, which opens into the internal orifice 60, has a height H160 in the illustrated example that is close to that H60 of the orifice. As an alternative, it can be provided that this height H160 is slightly greater than the height of the orifice 60. On the other hand, an intermediate passage 160, of lower height than the orifice 60, represents a clearly less preferred possibility of the invention.

[0069] As can be seen in Figures 7 and 8, the frame 1 is received in the main opening 130, which does not create any additional bulk inside the chamber itself. The invention takes advantage of the low-profile intermediate passage 160 to circulate ventilation air through the slot 60 of the ventilation unit. This ensures good ventilation quality while using a very small amount of space.

[0070] The secondary opening 2, provided within this framework, is therefore likely to have dimensions only slightly smaller than those of the main opening 130. Advantageously, the surface area of ​​this secondary opening is greater than 80%, and in particular 90%, of the surface area of ​​the main opening. Consequently, passage between the bedroom and the corridor is particularly convenient.

[0071] Finally, the ventilation unit 4, which can be quite bulky, is placed in the corridor, above the bed frame. This location is particularly well-optimized, as it does not obstruct the free movement of healthcare personnel or any medical equipment. While not shown, a purification unit of any standard type can be placed on one of the side walls of room II, for example, wall 112, or even on the ceiling of this room.

[0072] An example of implementing the combined access and ventilation device according to the invention will now be described. First, it is assumed that an infectious patient is admitted to the room. Under these conditions, if the fans 55 and 56 are switched on, the air in the room is drawn towards the enclosure 50, via the intermediate passage 160, the internal orifice 60, and then the channel 49. This air is then treated in the filters 53 and 54, with the filtered air being discharged outside the unit 4. via the external orifices 62. These different air displacements are illustrated in figures 5 and 7, being materialized by the solid arrows fl.

[0073] Furthermore, as this suction operation is carried out, it is understood that the pressure inside the room tends to decrease relative to the pressure in the corridor. This pressure difference is partially compensated, naturally, by an airflow (not shown) from the outside to the inside of the room. This air flows in particular through existing joinery, especially windows, as well as through other leaks in the room's walls, thus supplying the room with fresh air.

[0074] It is now assumed that an immunocompromised patient is admitted to the room. In this case, the ventilators are placed in a configuration opposite to that described above, in a manner known per se. If the ventilators 55 and 56 are switched on, the air in the corridor is drawn towards the enclosure 50, via the external ports 62. This air is then treated in the filters 53 and 54, the filtered air being blown into the room via the channel 49, the internal port 60, and then the intermediate passage 160. These various air movements are illustrated in Figures 5 and 7, and are indicated by the dashed arrows f2.

[0075] Furthermore, as this blowing operation progresses, it is understood that the pressure inside the chamber now tends to increase relative to the pressure in the corridor. This pressure difference is again partially compensated, naturally, by an airflow (not shown) from the inside to the outside of the chamber. As in the case of the suction described above, this air exits, in particular, through the existing window and door frames as well as other leaks in the chamber's walls.

[0076] Whether admitting an infectious patient or an immunocompromised patient, it is preferable that the patient be admitted to the room while the appropriate suction or ventilation procedure is already underway. Of course, it is also possible to admit a patient to the room initially, and then perform either of these suction or ventilation procedures.

[0077] In operation, as explained above, the ventilation unit control measures the pressure cascade between the inside of the room and the corridor. If this measured value falls outside a predetermined range, an alarm is triggered. This allows an operator to intervene quickly to correct the malfunction.

[0078] Figures 9 and 10 illustrate an alternative embodiment of the combined device according to the invention. In these figures, the mechanical elements analogous to those in Figures 1 to 8 are assigned the same reference numbers, increased by the number 200.

[0079] This variant differs from the embodiment shown in Figures 2 to 8, in particular in that the frame of the device is not inserted inside the main opening. On the contrary, this frame 201 is surface-mounted against the outside of the frame. More precisely, each rail 210, 211 is fixed to the outer face 343, 345 of a respective upright 342, 344. This fixing is ensured by any suitable means, in particular by means of screws 215, 216. As shown in [Fig. 10], the door 230 is offset towards corridor III, relative to the door 30 of [Fig. 7].

Claims

1. Demands Combined access and ventilation device (I) for a risk zone, in particular a room (II) of a hospital establishment, said risk zone comprising enclosure walls forming at least one main frame (140), this frame delimiting a main opening (130), said device comprising a frame (1) equipped with means (15,16) for mounting on the main frame, this frame forming a so-called secondary frame delimiting an opening (2) called secondary an opening (3) allowing the selective closing of the secondary opening a ventilation unit (4), provided on the upper part of the frame, this ventilation unit being capable of being fixed to the upper part of the main frame and comprising high-efficiency air filtration means (53, 54), as well as a suction and blowing system (55, 56) comprising at least one fan, said ventilation unit further comprising at least one internal opening (60) allowing air circulation between the interior of the risk zone and the ventilation unit, as well as at least one external opening (62) allowing air circulation between the ventilation unit and the exterior of the risk zone said device comprising sealing means (81, 82, 83, 84) which are capable of cooperating with the main frame (140) said combined device (I) being capable of delimiting, with the main frame, an intermediate air passage (160) communicating in service with the internal orifice (60) of the ventilation unit, said ventilation unit (4) being capable of circulating air so that - in a first configuration, air is extracted from outside the risk zone via successively the intermediate passage (160), the internal orifice (60) and the external orifice (62) so as to establish a depression in the risk zone; - in a second configuration, air is blown inside the risk zone via successively the external orifice, the internal orifice and the intermediate passage in order to establish overpressure in the risk zone.

2. Combined device according to the preceding claim, wherein the internal orifice is made in the form of a slot (60) provided on a front wall (42) of the ventilation unit, in particular at the lower end of this front wall, said front wall being intended to be applied against the main frame.

3. Combined device according to the preceding claim, wherein the height (H60) of said slot is between 10 mm and 150 mm, in particular between 10 mm and 50 mm.

4. Combined device according to the preceding claim, wherein the width (L60) of said slot is between 900 mm and 1500 mm, in particular between 1000 mm and 1250 mm.

5. Combined device according to any one of the preceding claims, wherein the area of ​​the secondary opening (2) is greater than 80%, in particular 90%, of the area of ​​the main opening (130).

6. Combined device according to any one of the preceding claims, wherein the upper region of the opening (3) is able to delimit, with the main frame, at least a part of the intermediate air passage (160).

7. Combined device according to any one of the preceding claims, wherein the filtration means comprise at least one high-efficiency filter (53, 54), two high-efficiency filters and two fans being advantageously provided in two separate compartments (51) of the ventilation unit (4).

8. A combined device according to any one of the preceding claims, wherein the sealing means comprise first so-called lateral seals (81,82), each of which is able to bear against a respective lateral post (142,144) belonging to the frame, each lateral seal being at least partially covered by a respective cover, this cover (17,18) being fixed on a lateral rail (10,11) of the frame and projecting opposite said lateral post; and a so-called upper seal (84), fixed on the ventilation unit so as to bear against an upper edge (146) belonging to the frame.

9. Risk zone, in particular room (II) of a hospital establishment, said risk zone comprising enclosure walls forming at least one main frame (140), this frame delimiting a main opening (130), said risk zone being equipped with a combined access and ventilation device (I) according to any one of the claims previous indications, the frame (1) of said combined device being either received at least in part in said main opening, or placed against the outer face of the main frame where the ventilation unit is surface-mounted against the outer face of a so-called upper edge of the main frame, extending above said main opening, said combined device (I), in particular the upper region of its opening (3), delimiting, with the main frame, in particular with said upper edge (146), an intermediate air passage (160) which communicates with the internal orifice (60) of the ventilation unit, this intermediate passage being in particular located opposite this internal orifice.

10. Hazard zone according to the preceding claim, wherein the height (H 160) of the intermediate passage (160) is equal to the height (H60) of the internal orifice (60), or is strictly greater than the height of this internal orifice.

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