FR2849169A1 - Oven for cooking/baking foods, has admission pipe that comes out of regulation chamber and heating device, when pipe is in high extremity, and is sealed by liquid in chamber during its high level, when pipe is in low extremity - Google Patents

Abstract

The oven has a heating chamber to receive foods and a regulation chamber (33) partly filled with liquid whose volume changes between high and low levels. The chamber (33) communicates with a heating device by an air entrance. An admission pipe (45) comes out of the chamber (33) and the device, when the pipe is in the high extremity. The pipe is sealed by the liquid during its high level, when the pipe is in the low extremity.

Description

i

  The present invention relates to ovens for cooking food.

  More particularly, the invention relates to an oven comprising: an enclosure intended to receive food to be heated and to contain a cooking atmosphere, this enclosure comprising two horizontal walls, forming respectively a hearth and a vote, connected by at least two walls vertical lateral, this enclosure being closed by at least one door also vertical, and communicating with the outside by an opening for evacuating gases under pressure in the enclosure, and a heating device for heating the cooking atmosphere.

  Furnaces of this type are known in which, for example when steam is produced or when the door is closed or when the heating device is a gas burner (production of combustion gases or overpressure at ignition), there may be an overpressure in the enclosure, more or less significant and for a longer or shorter period of time For obvious safety reasons, these overpressures must be managed, reduced or even eliminated In ovens In the prior art, this management is generally taken care of by an opening provided with a mechanical shutter.

  This type of shutter requires regular maintenance, otherwise it may no longer function properly, in particular when it becomes dirty. Its securing function is no longer effectively and reliably ensured.

  The object of the present invention is in particular to overcome this drawback.

  To this end, according to the invention, an oven is provided which, in addition to the characteristics already mentioned, is characterized by the fact that it comprises: a regulation chamber, at least in part 5 filled with a liquid whose volume is adapted to vary between a high level and a low level, this regulation chamber communicating with the enclosure by an air inlet, and an intake duct which extends between a high end and a low end, the high end opening out of the regulation chamber and the enclosure, and the low end being closed by the liquid, when the level of the liquid corresponds substantially to its high level.

  These provisions make it possible to manage the overpressures in the enclosure, in a non-mechanical manner, which makes it possible to overcome the maintenance constraints that the ovens of the prior art require, in an adjustable manner because by modifying the level of the liquid it it is possible to stop or more or less allow the gases coming from the enclosure to pass, and in a reliable manner, because with a liquid there is no risk of inadvertent obturation or mechanical blocking, and even if the lower end of the intake pipe dips below the high water level, in the event of too high an overpressure the gases can push back the water level, "bubble" and escape through the intake pipe . In preferred embodiments of the invention, it is optionally possible to have recourse to one and / or the other of the following provisions: it comprises an evacuation chamber, at least partly filled with a liquid whose volume is adapted to vary between the high level and the low level, this evacuation chamber communicating with the regulation chamber; it comprises an evacuation tube extending between the evacuation opening and a high opening end, in the evacuation chamber above the high and low levels of the liquid; it comprises a chimney extending between a first end communicating with the outside of the evacuation chamber and a second end arriving above the high level of the liquid, this second end leaving the gases in overpressure in the enclosure s 'escape, via the evacuation tube; it comprises a turbine, arranged inside the enclosure, for stirring the cooking atmosphere heated by the heating device, this turbine creating a vacuum zone in the enclosure, the air inlet being located substantially in said depression area of the turbine; it comprises a regulation box itself comprising the regulation chamber and the evacuation chamber, these two chambers constituting volumes at least partially separated from each other, communicating with each other by a restricted passage adapted to allow circulate the liquid between these chambers; it comprises, in the evacuation chamber, a first temperature probe for measuring the temperature of the gases coming from the evacuation opening and, in the regulation chamber, a second temperature probe for measuring the temperature of the gases arriving in enclosure 30 by the air inlet; it comprises in the evacuation chamber, a first temperature probe for measuring the temperature of the gases coming from the evacuation opening and a second temperature probe placed under the low level of the liquid in the evacuation chamber; it includes means for calculating the humidity level in the oven as a function of the temperatures measured on the first and second probes; it includes means for producing steam suitable for supplying steam to the enclosure; the opening for discharging the overpressure gases in the enclosure is located below the heating device; the discharge opening opens at the substantially lowest point of the floor; and the discharge opening communicates with a siphon suitable for discharging liquids and condensates from the enclosure while preventing fresh air from entering the enclosure. Other aspects, aims and advantages of the invention will appear on reading the description of several embodiments.

  The invention will also be better understood using the drawings, in which: FIG. 1 is a schematic perspective view of a first embodiment of the oven according to the invention; Figure 2 is a schematic plan of the oven 25 shown in Figure 1, in which, in particular, the enclosure of this oven is shown in section in a vertical plane perpendicular to the bottom wall, cutting the bottom wall and the heating device substantially in the middle; Figure 3 is a perspective view of the cooling circuit of the vote of the furnace shown in Figures 1 and 2; FIG. 4 schematically represents, in a manner analogous to FIG. 2, a variant of the control box of the furnace shown in FIG. 2; FIG. 5 schematically represents, in a manner analogous to FIG. 3, a variant in perspective of the cooling circuit of the vote of the furnace shown in FIGS. 2 and 3; Figure 6 shows schematically, in a view similar to that of Figure 2, a second embodiment of the oven according to the invention; Figure 7 shows schematically, in a view similar to those of Figures 2 and 6, a third embodiment of the oven according to the invention; and Figure 8 schematically shows, in a view similar to those of Figures 2, 6 and 7, a fourth embodiment of the oven according to the invention.

  In the different figures, the same references designate identical or similar elements.

  Other aspects, objects and advantages of the invention will appear on reading the description of one of its 20 embodiments.

  Four examples of embodiments of the oven according to the invention are described below in relation to FIGS. 1 to 8.

  According to the first mode, represented in FIG. 1, the oven 1 according to the invention comprises an enclosure 2 (or muffle) contained in a formwork 3 This formwork 3 comprises means 4 for regulating the temperature in the enclosure 2, as well as a door 5 intended for the introduction of food to be heated and / or cooked in enclosure 2.

  The enclosure 2 has a substantially parallelepiped shape with a front face 6, open or closed by the door 5, a bottom wall 7 opposite the front face 6, two side walls 8 vertical, between the front face 6 and the wall of bottom 7, as well as a bottom 9 and a vote 10 forming two horizontal walls All these walls are made of metal sheets.

  As shown in FIG. 2, the enclosure 2 5 also comprises a heating device 11, a turbine 12, a protective grid 13 and slides 14.

  The heating device 11 is placed inside the enclosure 2, facing the turbine 12.

  According to the present embodiment, it is a burner 10 with combustion gas It is supplied with combustion gas by a conduit 15 This burner 11 is ignited by an electrode 16 electrically supplied by a wire 17 arriving in the burner 11 via the conduit 15 This burner 11 also includes a flame control device 16a, for example by ionization, connected to a control box (not shown) by a wire 17a The wires 17 and 17a exit from the conduit 15 , at the level of the cable gland.

  The combustion gas is advantageously an air / gas mixture. This mixture is produced at the level of a mixer 18. The air is supplied via a booster 19 Thus, the air / gas mixture arrives at the burner 11 in slight overpressure The combustion gas supply is managed by electronic means (not shown) In the event of the burner 11 stopping, for example when a set temperature is reached, a slight pressure is maintained by the booster 19 in order avoid any rise of steam in the mixer 18.

  The turbine 12 is mounted substantially in the center of the bottom wall 7 It consists of a disc 20 30 centered on an axis of rotation 21 At the periphery of this disc 20, the turbine 12 comprises a plurality of blades 22 regularly angularly distributed around of the axis of rotation 21 These blades 22 are for example made up of flat rectangular strips extending in a plane substantially perpendicular to the disc 20 and passing through the axis of rotation 21 This symmetry with respect to the axis of rotation 21 allows to rotate the blades clockwise and counterclockwise 5, in an equivalent manner The turbine 12 is rotated, around the axis of rotation 21, by a motor 24, for example electric The direction of rotation of the turbine 12 is advantageously alternated periodically The turbine 12 makes it possible to distribute the heat energy 10 in the enclosure 2.

  During their rotation, the blades 22 travel a circular trajectory centered on the axis of rotation 21 and delimit a central space 23.

  The burner 11 is placed opposite the central space 23. Part of this burner 11 possibly penetrates into this central space 23.

  The protective grid 13 extends in a vertical plane opposite the disc 20, in front of the burner 11 and the turbine 12, relative to the cooking space 25 intended to receive the food to be heated and situated between this burner 11 and door 5.

  The slides 14, ten in number, are arranged substantially horizontally on the side walls 8 Each side wall 8 has a slide 25 14 of each pair These slides 14 make it possible to maintain trays 26 on which the food to be heated is arranged and / or to be cooked Advantageously, the trays 26 have perforated bottoms 27.

  The enclosure 2 communicates with the outside via a discharge opening 28 This discharge opening 28 allows the cooking atmosphere contained in the enclosure 2 to escape, when this atmosphere is under overpressure with respect to the pressure outside the enclosure 2 This discharge opening 28 is located below the heating device 11 More specifically, the discharge opening 28 opens at the substantially lowest point of the floor 9 Indeed, in the embodiment described here, the sole 9 has sides inclined downward towards a point located substantially in the middle.

  The condensates formed in the enclosure 2 flow along the inclined sides in the direction of the discharge opening 10, from which they are discharged towards the outside of the enclosure 2 For this purpose, the discharge opening 28 communicates with a siphon 29 When the siphon 29 is filled, that is to say in normal condition of use, the liquid held in the bottom of the siphon 29 15 prevents the flow of fresh air towards the exhaust opening 28, and therefore towards enclosure 2, thus contributing to the stability and homogenization of the temperature in this enclosure 2, avoiding the introduction of fresh air through the exhaust opening 28 .

  These condensates can come from food being cooked in enclosure 2 and / or from steam production means 30 adapted to supply steam in enclosure 2.

  According to a variant not shown of this embodiment, the discharge opening 28 can open at one of the side walls 8 and / or bottom 7 of the enclosure 2 In this case, the condensates are discharged by different means According to yet another variant, the discharge opening 28 is located at the junction of one of the side walls 8 or of the bottom 7 and of the bottom 9.

  The oven 1 according to the embodiment of the invention described here, comprises a regulation box 31 This regulation box 31 comprises a discharge chamber 32 and a regulation chamber 33 The discharge chamber 32 and the regulation chamber 33 communicate with each other by a restricted passage 51.

  The regulation unit 31 is located in the formwork 3, behind the bottom wall 7 with which it communicates by means of an air inlet 44.

  The control unit 31 is partly filled with water by means of a water supply 34 The level of water 10 in the control unit 31 is controlled by a first overflow 35 which flows at the level of the trap 29.

  Thus, even when the condensates are insufficient to prevent the flow of fresh air through the siphon 29, the latter can be filled directly by the water supply 15, via the first overflow 35.

  The water level in the control box 31 can also be controlled by a drain valve 36. This drain valve 36 controls the flow of water in a drain pipe 37 connecting the bottom of the control box 31 to the trap 29.

  The volume of water in the regulating box 31, and therefore in the discharge chamber 32, varies between a high level, corresponding to the height of the first overflow 35, and a low level, corresponding to the height of the 25 junction of the drain pipe 37 with the regulation unit 31.

  An evacuation tube 38 extends between the evacuation opening 28 and a high end 39 opening into the evacuation chamber 32 above the high and low levels of the water in the regulation chamber 32 Ce evacuation tube 38 opens between the evacuation opening 28 and the siphon 29. The evacuation chamber 32 also communicates with a chimney 40 This chimney 40 extends between a first end 41 situated outside the chamber discharge 32 and a second end 42 located above the high water level When the pressure increases in the enclosure 2, the gases contained in the enclosure 2 escape through the outlet opening 28, then through the exhaust duct 38 and the chimney 40.

  The regulation chamber 33 is attached, in the present embodiment, to the evacuation chamber 32. The regulation chamber 33 and the evacuation chamber 32 are separated by a partition 43 The partition 43 does not separate so Completely hermetic, the evacuation and regulation chambers 32 In fact, this partition 43 limits, without completely preventing them, the gas and aqueous exchanges 15 between these two chambers 32, 33, which take place through the restricted passage 51.

  The regulation chamber 33 communicates with the enclosure 2 by the air inlet 44 opening into the enclosure 2 substantially at the level of a vacuum zone 20 created by the rotation of the turbine 12 The regulation chamber 33 also communicates with the outside thanks to an intake duct 45 which allows air to enter the regulation chamber 33, if the water level is located under the intake duct 45.

  But, in the event of overpressure in the enclosure 2, even if the discharge opening 28 or the discharge tube 38 is blocked, the burnt gases can escape through the intake duct 45, whatever whatever the level of water, between its high level and its low level, in the regulation chamber 33 If the intake duct 45 plunges under water level in the regulation chamber 33, the burnt gases can " bubbling "and escaping The regulation chamber 33 therefore makes it possible not only to manage humidity, it by the entry of fresh and drier air via the intake duct 45, by varying the water level, but also the pressures in the enclosure 2, and this without a mechanical system for opening or closing conduits. The control box 31 therefore makes it possible to fulfill functions similar to mechanical systems, such as shutters, but has the advantage of not being able to clog and block, thus giving the oven according to the invention a secure increased tee.

  A first temperature sensor 46 is placed in the evacuation chamber 32 in order to measure the temperature of the gases coming from the evacuation opening 28 and conveyed by the evacuation tube 38 A second temperature sensor 47 is placed in the regulation chamber 33 15 in order to measure the temperature of the gases arriving in enclosure 2 at the level of the air inlet 44 The first probe 46 measures a temperature representative of that of enclosure 2, given that the fresh air from outside this enclosure 2 is prevented by the siphon 20 29 The second probe 47 measures a temperature representative of that of the air arriving through the intake duct 45.

  The first 46 and second 47 temperature probes are connected to means 48 for calculating the humidity level 25 in the enclosure 2 The calculation of the humidity level in enclosure 2, by the calculation means 48, is carried out conventionally from a prior calibration.

  In the present embodiment, the oven according to the invention also comprises means for producing steam 30 adapted to supply steam to the enclosure 2. These means for producing steam 30 comprise, according to the present embodiment, a water column 49 and a diffuser 50.

  The water column 49 includes a water reserve 52 and a tube 53.

  The reserve 52 is located outside the enclosure 2 It has a high outlet 54 acting as an overflow 5 and corresponding to the maximum level of water in the column 2 The tube 53 allows the water to flow from the reserve 52 to the diffuser 50 The water pours from the tube 53 at the diffuser 50 via a low outlet 55.

  The diffuser 50 consists of a rotating disc 10 integral with the axis of rotation 21 of the turbine 12 The diffuser disc 50 is located in the central space 23 opposite the burner 11 The diameter of the diffuser disc 50 is substantially equal to that of the burner 11 Thus, the burner 11 heats the disc 50.

  The water flowing from the column 49 in the vicinity of the disc 50, falls on the latter The disc 50 heated by the burner 11 then vaporizes part of this water Another part of the water is projected by the disc 50 and is vaporized in the flames of the burner 11 Yet another part of the water, which is neither vaporized in contact with the disc 50, nor in the flames of the burner 11, is projected onto the walls 7, 8, 9 and 10 and in particular on vote 10.

  The water projected onto vote 10 can drip onto the upper plate, then thanks to the perforated bottoms 27, from plate 25 to plate 26, towards the floor 9 at the level of which the water is collected by the opening of evacuation 28 Thus, the formation of a desiccated and / or burnt skin on the food placed in the trays 26 is avoided.

  The proportion of water projected onto the vote 10 can be controlled by varying the speed of rotation of the diffuser disc 50.

  The pressure difference in column 49, between the maximum level and the low outlet 55, is between and 30 mbar As long as the water level in column 49 is kept constant, this pressure difference also remains constant, unless the pressure in the enclosure 2 increases As long as the pressure in the enclosure 2 remains substantially equal to the pressure outside the enclosure 2, that is to say the atmospheric pressure, the water flow flowing through the low outlet 55 is substantially constant On the other hand, if steam is produced in enclosure 2, the pressure in enclosure 2 increases relative to the pressure outside enclosure 2 The pressure difference between the maximum level and the low outlet 55 then decreases and therefore the flow of water flowing through the low outlet 55 also decreases. The water column 49 therefore allows self-regulation of the production of the steam in enclosure 2.

  The high outlet 54 communicates with the water supply 34 The water flowing through the high outlet 54 arrives in the control unit 31.

  As shown in FIG. 3, the tube 53 20 comprises, between the water reserve 52 and the low outlet 55, a portion forming a cooling circuit 56 This cooling circuit 56 has a serpentine shape which extends, at outside the enclosure 2, on a part of the vote 10, in contact with the latter For example, the coil coils closely with grooves formed by stamping in the sheet metal of the vote 10.

  Thus, the vote 10 is cooled, which promotes the condensation of at least part of the water vapor contained in the atmosphere of the enclosure 2 The condensed water 30 on the vote 10 can drip into the upper shelf.

  As the plates 26 have perforated bottoms 27, the water then drips from plate to plate towards the floor 9 at the level of which the water is collected by the evacuation opening 28 Again, the formation of '' parched and / or burnt skin on the food placed in the trays 26.

  Outside the periods during which the oven 1 5 is used for cooking food, the water column 49 can be used to supply detergent in the vicinity of the turbine 12. When detergent flows through the low outlet 55, it falls on the diffuser disc 50, which, rotating with the turbine 12, around the axis of rotation 21, 10 projects the detergent towards the blades 22 of the turbine 12, which themselves project the detergent towards the walls 7, 8, 9, 10 of enclosure 2 and door 5 Thus, almost all of the surfaces of the walls 7, 8, 9, 10 of enclosure 2 and of door 5 are covered with 15 detergent It is possible to optimize the distribution of the detergent on these walls 7, 8, 9, 10, as well as on the door 5, by varying the speed of rotation of the disc 50 and of the turbine 12.

  According to a variant illustrated by FIG. 4, the first probe 46 is placed in the evacuation chamber 32 in the manner indicated above but the second probe 47 is placed, also in the evacuation chamber, in the water , below the low level Thus, the first probe 46 measures a temperature representative of that of the enclosure 25 2, as explained above, and the second probe 47 measures a substantially stable temperature which can serve as a reference temperature for determining humidity level in enclosure 2.

  According to another variant illustrated by FIG. 5, the cooling circuit 56 is placed upstream from the water reserve 52.

  The second embodiment of the oven 1 according to the invention is shown in Figure 6 According to this embodiment, the oven 1 according to the invention is similar to that described in relation to the first embodiment.

  It is essentially distinguished from it by the fact that the heating device 11 consists of an electrical resistance 5 instead of a gas burner. This electrical resistance 11 is situated substantially in the same place as the gas burner described in the previous embodiment.

  This electrical resistance 11 is possibly at least partially located in the central space 23. It fulfills essentially the same functions as the gas burner. In particular, it heats the diffusing disc 50. According to a variant, the water in the column 49, flows directly onto the resistor (In this case, the furnace 1 according to the invention does not necessarily have a diffusing disc 50) The vapor then produced, is sucked up and distributed in the enclosure by the turbine 12.

  The third embodiment of the furnace 1 according to the invention is shown in FIG. 7 According to this embodiment, the furnace 1 according to the invention is similar to that described in relation to the second embodiment It differs therefrom essentially by the fact that the diffusing disc 50 is replaced by a diffusing cylinder 57 and that the heating device 11 consists of an electrical resistance arranged in a ring 25 around the turbine 12.

  The diffuser cylinder 57 has a cylindrical wall 58 of revolution about the axis of rotation 21.

  This wall 58 is metallic and pierced with holes 59 One of the two ends of the diffuser cylinder 57 is closed by 30 a partition 60 in the form of a disc, perpendicular to the axis of rotation 21 This partition 60 is integral with the axis of rotation 21 It is centered on the axis of rotation 21 The diffuser cylinder 57 therefore rotates with the turbine 12.

  The other end of the diffuser cylinder 57 is open In fact, the bottom outlet 55 of the water column 49 is located in the diffuser cylinder 57 Thus, the water flowing from the column 49 is partly sprayed by the wall cylindrical 5 58 in rotation The water spray comes out through the holes 59 of the cylindrical wall 58 and through the open end of the cylinder, then projected towards the blades 22 of the turbine 12 and towards the walls 5, 7, 8, 9, 10 of the enclosure 2 The water reaching the vote 10 can drip into the trays 26 and 10 to prevent drying of the cooked and / or reheated food in the oven 1.

  Similarly, outside the periods during which the oven 1 is used for cooking food, the water column 49 can be used to deliver detergent to the vicinity 15 of the turbine. Thus, does the diffuser cylinder 57 ensure essentially the same functions as the diffuser disc 50 described in relation to the previous embodiments. The fourth embodiment of the furnace 1 according to the invention is shown in FIG. 8 According to this embodiment, the furnace 1 according to the invention is similar to that described in relation to the second embodiment It differs therefrom essentially by the fact that the heating device 11 is placed in a ring around 25 of the turbine 12, as in the third embodiment, and that additional heating means 61 are placed substantially opposite the diffuser disc 50, in order to heat the latter These additional heating means 61 consist, for example, of an electrical resistance.

  The oven according to the invention can be the subject of numerous variants without departing from the scope of the invention.

  Thus, according to a variant not shown, the enclosure 2 has a front face and a rear face, open or closed, each by a door. In this case, a turbine 12 is mounted, for example, on at least one side wall 8 and the heating device 11 is placed opposite each turbine 12.

  According to other variants, several turbines 12 and several burners 11 are arranged on the same wall.

Claims (10)

  1 oven for cooking food comprising: an enclosure (2) intended to receive the food 5 to be heated and to contain a cooking atmosphere, this enclosure (2) comprising two horizontal walls, respectively forming a sole (9) and a vote (10), connected by at least two vertical side walls (7,8), this enclosure (2) being closed by at least one door (5) 10 also vertical, and communicating with the outside by a discharge opening (28) gases overpressure in the enclosure (2), and a heating device (11) for heating the cooking atmosphere characterized in that it comprises: a regulation chamber (33), at least in part filled with a liquid whose volume is adapted to vary between a high level and a low level, this regulation chamber (33) communicating with the enclosure by an air inlet (44), an intake duct (45) which extends between a high end and a low end, the e x upper end opening out of the regulation chamber (33) and the enclosure (2), and the lower end being closed by the liquid, when the liquid level corresponds substantially to its high level.   2 Oven according to claim 1, comprising a discharge chamber (32), at least partly filled with a liquid whose volume is adapted to vary between the high level and the low level, this discharge chamber (33 ) communicating with the regulation chamber (33).   3 Oven according to claim 2, comprising a discharge tube (38) extending between the discharge opening (28) and a high end (39) opening into the discharge chamber (32) above high and low fluid levels. 4 Oven according to claim 3, comprising a chimney (40) extending between a first end (41) communicating with the outside of the evacuation chamber (32) and a second end (42) arriving above the level top of the liquid, this second end allowing the gases under overpressure in the enclosure (2) to escape, via the evacuation tube (38).   Oven according to one of claims 2 to 4, comprising a control box (31) itself comprising the control chamber (33) and the discharge chamber (32), these two chambers (32, 33) constituting volumes at least partially separated from each other, communicating with one another by a restricted passage (51) adapted to let the liquid circulate between these two chambers (32, 33).   6 Oven according to one of claims 2 to 5, comprising, in the discharge chamber (32), a first temperature probe (46) for measuring the temperature of the gases from the discharge opening (28) and, in the regulation chamber (33), a second temperature probe (47) for measuring the temperature of the gases arriving in the enclosure (2) through the air inlet (44).   7 Oven according to one of claims 2 to 6, comprising, in the evacuation chamber (32), a first temperature probe (46) for measuring the temperature of the gases coming from the evacuation opening (28) and a second temperature probe (47) placed under the low level of the liquid in the evacuation chamber (32).   8 Oven according to one of claims 6 and 7, comprising means for calculating (48) the humidity in the oven (1) as a function of the temperatures measured on the first (46) and second (47) probes.   9 Oven according to one of the preceding claims, comprising a turbine (12), disposed inside the enclosure (2), for stirring the cooking atmosphere 5 heated by the heating device (11), this turbine (12) creating a vacuum zone in the enclosure (2), the air inlet (44) being located substantially in said vacuum zone of the turbine (12).   Oven according to one of the preceding claims, 10 comprising steam production means (30) adapted to supply steam to the enclosure (2).   11 Oven according to one of the preceding claims, wherein the discharge opening (28) of the overpressure gases in the enclosure (2) is located below the heating device (11).   12 Oven according to one of the preceding claims, wherein the discharge opening (28) opens at the substantially lowest point of the hearth (9).   13 Oven according to one of the preceding claims, 20 in which the evacuation opening (28) communicates with a siphon (29) adapted to evacuate liquids and condensates from the enclosure (2) while avoiding rising d fresh air in the enclosure (2).