TECHNICAL FIELD

The present invention relates to a ventilation device, a vehicle with such a device, and a method for venting a space in which heat is generated, in particular an engine room of a vehicle.

BACKGROUND AND PRIOR ART

The present invention relates to a ventilation device, a vehicle with such a device, and a method for venting a space in which heat is generated according to the appended claims.

As a lot of different types of machinery and/or devices generate heat as a by-product of the work they perform venting said heat is a common problem within several fields, such as industrial processes, other machinery, or vehicles. Dissipating heat may be done in various ways, for example using fans, heat sinks, water cooling or other. For vehicles in particular, build-up of heat needs to be avoided as the engines, batteries and other equipment may take harm if being subjected to overexposure of heat. An engine, and especially an internal combustion engine, which is well cooled works better and has a longer lifespan than a sub-par cooled engine for example.

For heavy vehicles such as buses, this is a very important issue as a bus often is used over long periods of time, the weight the engine supports is large, and the design of buses is separate from that of a, for example, a car. Buses are commonly built with the engine at the back of the bus, which makes it more difficult to use the wind hitting the front of the bus as cooling medium. Furthermore, as heat rises upwards and said type of engine is covered on top by the seats and body of the bus, the heat generated by the engine of a bus might require special attention compared to that of a normal car. D1 - DE102015008248 A1 describes a ventilation system for a bus comprising a chimney. Said chimney is arranged in fluid communication with the engine room wherein heat generated by the engine may rise up through the chimney and be vented to the surrounding atmosphere above the roof of the bus. The engine room further comprises an air inlet arranged to have cold outside air flow in through said inlet to the engine room. Thereby a continuous air flow going in through said inlet, cooling the engine, and transports heat from the engine via the chimney to the outside of the bus is provided.

There is however drawbacks with the above described ventilation system. As the air flowing into the engine room might be subjected to high air resistance, and also cause an increased air pressure in the inlet, the air of the system might not flow as intended and sub-par ventilation might be the result. Additional fans might be required to guarantee that the system provides the intended venting effect without relying on the airflow being sucked in via the air inlet. Having additional fans installed in an engine room is often not desired as the environment therein is exposed to a lot of contamination in the form of oil, dirt or similar, which may impede the function of said fans and/or lead to a malfunction of said fans.

SUMMARY OF THE INVENTION

Despite prior art there is therefore a need to develop a ventilation device, which can improve the ventilation of a first space in which heat is generated, in particular an engine room of a vehicle. There is also a need to develop a ventilation device which functions without the need to install additional fans inside of said first space.

Furthermore, there is a need to develop a ventilation device which reduces the risk of pressure build-up within said ventilation device to provide a consistent and reliable venting of said first space.

An object of the present invention is thus to provide a ventilation device, which can improve the ventilation of a first space in which heat is generated, in particular an engine room of a vehicle. Another object is to provide a ventilation device which functions without the need to install additional fans inside of said first space. Another further object of the invention is to provide a ventilation device which reduces the risk of pressure build-up within said ventilation device to provide a consistent and reliable venting of a first space.

The herein mentioned objects are achieved by a ventilation device, a vehicle with such a ventilation device, and a method for venting a space according to the independent claims.

According to an aspect of the invention the ventilation device for a first space, in particular an engine room of a vehicle, comprises a chimney extending from said first space. The chimney comprises an inlet and an outlet, wherein the inlet is arranged in fluid communication with the first space and the outlet is in fluid communication with a surrounding atmosphere. The device further comprises an auxiliary second space. The second space being arranged adjacent the chimney and being in fluid

communication with the chimney by means of at least one opening. Said chimney is an individual space extending in length along the auxiliary second space, wherein an airflow flowing from the auxiliary second space to the surrounding atmosphere via the chimney causes an ejector effect in the chimney which vents air from the first space. This has the advantage that a cooling airflow may be guided via said auxiliary second space to effectively vent the engine room via the chimney. Thereby a device is provided which can vent the heat generated in a first space without altering the design of said first space. This is beneficial as the auxiliary second space may be designed for an effective airflow only and no consideration is needed to provide said airflow in the first space by default. Thereby the first space can be manufactured in a simple and effective way where only the needs of the engine or the like needs to be taken into account.

According to another aspect of the invention at least one fan is arranged in the auxiliary space, which at least one fan guides air from the surrounding atmosphere to the chimney via the auxiliary space.

This has the advantage that the benefits of a guided airflow provided by a fan are provided without installing said at least one fan in the first space itself. This is beneficial as the airflow may be guided more effectively by means of at least one fan while said at least one fan will not be subjected to the potentially contaminated environment in the first space. This has the advantage that the at least one fan can operate under better working conditions and a longer operating lifespan is thereby ensured.

According to another aspect of the invention said at least one fan is arranged in an outer wall of said auxiliary space. This has the advantage that the airflow may be guided more effectively from the surroundings to said chimney.

According to yet another aspect of the invention the first space is an engine room with an engine, and the at least one fan is part of a heat exchanger unit of the engine.

This has the advantage that the fans of the heat exchanger unit may be operated in the cleaner working environment of the auxiliary second space whilst still perform the heat exchange from the engine. A further advantage with this is that the fan of the heat exchanger unit may at the same time operate as a driving force for the airflow flowing in the chimney and hence drive the ejector effect.

According to a further aspect of the invention the at least one opening of the chimney is provided with angled guide vanes, which vanes directs airflow from the axillary space towards the outlet of the chimney.

This has the advantage that the airflow is more effectively guided in the right direction within the chimney in regards of venting the first space. This is beneficial as the risk of the airflow moving from the auxiliary second space towards the first space is reduced.

According to an even further aspect of the invention the auxiliary second space further comprises at least one baffle plate which can move between a closed state and an open state, wherein the open state provides fluid communication with the surrounding atmosphere, and the at least one baffle plate moves to the open state when the pressure within the auxiliary second space reaches a predetermined value.

This has the advantage that a build-up of high pressure is avoided in the auxiliary second space and the chimney. If the air within the chimney would reach a too high pressure the flow within the chimney could potentially risk flowing backwards, towards the first space or the auxiliary second space. The at least one baffle plate in an open state prevents this by letting air flow outside to the surrounding atmosphere and relieve such pressure build-up.

According to an aspect of the invention the at least one baffle plate is spring-loaded with a spring, and biased to be in the closed state by means of a spring force of the spring, and move to the open state when the pressure of the auxiliary second space reaches the predetermined value, which overcomes the spring force.

This has the advantage that the pressure within the auxiliary second space and thereby also the chimney may be controlled automatically by means of said spring force. This is beneficial as the internal pressure within the system is not reliant on additional devices or functions and/or control of such devices or functions. Hence, an effective pressure relieving system is provided which is easy and cost effective to manufacture.

According to another aspect of the invention the at least one baffle plate is moved between the closed state and the open state by means of an actuating device.

This has the advantage that a customizable device is provided, wherein the actuating device may be designed to work with a variety of predetermined pressures, which predetermined pressures may be initially set and later on changed by means of changing the operating parameters of the actuating device.

According to yet another aspect of the invention the device further comprises a sensor arranged to determine the pressure of the auxiliary second space wherein the actuating device can move the at least one baffle plate to the open state based on the determined pressure. This has the advantage that the pressure of the auxiliary second space may be continuously monitored in a non-complex manner, wherein said monitoring provides a reliable ventilation device in which pressure build-up is continuously alleviated.

According to a further aspect of the invention a vehicle is provided, which vehicle comprises a ventilation device according to the present invention.

This has the advantage that a vehicle with a ventilation device is provided, which ventilation device effectively cools the engine of said vehicle in a simple and reliable manner. Thereby the engine of the vehicle will operate under better working conditions and longevity of the engine may be increased.

According to yet a further aspect of the invention a method for venting a first space by using a ventilation device is provided. The ventilation device comprises a chimney extending from the first space, the chimney comprising an inlet and an outlet, wherein the inlet is arranged in fluid communication with the first space and the outlet is in fluid communication with a surrounding atmosphere. The device further comprises an auxiliary second space, the second space being arranged adjacent the chimney and being in fluid communication with the chimney by means of at least one opening, the method comprising the step of:

a) guiding an airflow from the auxiliary second space to the surrounding atmosphere via the chimney so as to cause an ejector effect in the chimney which vents the air in the first space.

This has the advantage that a method is provided, which method can vent a first space without the need for additional fans or similar within said first space. This is beneficial as the working environment in the first space might not be beneficial for such fans, if the need to vent said first space comes from, for example an engine which generally also generates contamination for said first space.

According to another aspect of the invention the auxiliary second space further comprises at least one baffle plate which can move between a closed state and an open state, wherein the open state provides fluid communication with the surrounding atmosphere, and wherein the method further comprises the step of: b) opening the at least one baffle plate to equalize the pressure within the auxiliary second space. This has the advantage that a method is provided which can vent a first space and at the same time alleviate the risk of pressure build-up with the ventilation device being used.

According to yet another aspect of the invention the auxiliary second space further comprises a sensor, arranged to determine the pressure of the auxiliary second space, and wherein the method further comprises the step of: c) after a) and before b) determining the pressure within the auxiliary second space by means of the sensor This has the advantage that the pressure within the auxiliary second space may be constantly monitored wherein the measured pressure may be used to know when the baffle plates are to be moved to the open state, which in turn provides a reliable working environment of the at least one fan of the ventilation device as the risk of pressure build-up is securely avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

Below is a description of, as examples, preferred embodiments of the invention with reference to the enclosed drawings, in which: Figure 1 schematically illustrates a vehicle provided with a ventilation device according to the invention,

Figure 2 schematically illustrates a perspective view of an auxiliary second space of a ventilation device according to the invention,

Figure 3 schematically illustrates a perspective view of an auxiliary second space of a ventilation device, comprising baffle plates, according to the invention, Figure 4 schematically illustrates a cross-sectional side view of a ventilation device according to the invention, and

Figure 5 shows a flowchart of a method for venting a first space according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Figure 1 schematically illustrates a vehicle 1 provided with a ventilation device 3 according to the invention. The vehicle 1 comprises an engine 5, situated within a first space 7 of the vehicle 1 , a chimney 9 extending from said first space 7, the chimney 9 comprising an inlet 1 1 and an outlet 13, wherein the inlet 1 1 is arranged in fluid communication with the first space 7 and the outlet 13 is in fluid communication with a surrounding atmosphere outside of the vehicle 1 . The chimney 9 is an individual space separated from the surroundings by walls. The ventilation device 3 further comprises a second auxiliary space 15, said space 15 being arranged adjacent the chimney 9. Said chimney 9 is extending in length along the auxiliary second space 15. The auxiliary space 15 being in fluid communication with the chimney 9 by means of a plurality of openings 17, wherein an airflow flowing from the auxiliary second space 15 to the surrounding atmosphere via the chimney 9 causes an ejector effect in the chimney 9 which vents the air in the first space 7. The engine 5 may be an internal combustion engine and/or an electrical machine and the heat generated from the engine 5 may be vented from the first space 7 by means of said ejector effect without the need to place fans for this object within the first space 7. The first space 7 comprises at least one air intake opening 19 for outside air which will flow through the first space 7 and cool the engine 5. Said air will then be vented back to the surrounding atmosphere outside of the vehicle 1 via the chimney 9 of the ventilation device 3. The at least one air intake opening 19 of the first space 7 may be by means of air ducts or similar, or being incorporated in existing mechanical structures of the vehicle 1 , such as using the propeller shaft tunnel of the vehicle 1 as an air intake opening 19. The auxiliary second space 15 further comprises at least one fan 21 being arranged in an outer wall of the auxiliary second space 15, which at least one fan 21 guides the air from the surrounding atmosphere to the chimney 9 via the auxiliary second space 15. The at least one fan 21 may however be placed anywhere within the auxiliary second space 15, wherein additional openings for intake of air may be arranged to the auxiliary second space 15 for intake of air from the surrounding atmosphere.

The principle of an ejector effect is a way of creating a suction effect in the vicinity of a nozzle in which nozzle a motive fluid is guided and directed. By locally increasing the pressure of the motive fluid within the nozzle, the velocity of said fluid will then be increased when discharged from said nozzle, and the pressure locally decreased at the same time. By guiding the direction of a motive fluid in a specific direction said motive fluid will then cause a suction effect in the vicinity of said nozzle due to the locally lowered pressure. When a fluid intake opening, through which a secondary fluid which is to be vented is flowing, is arranged in fluid communication with the suction effect, said fluid which is to be vented will be sucked in by the suction effect and led away from the intake opening and transported through adjacent fluid transportation means, usually called a diffuser. It is to be understood that the openings 17 of the ventilation device 3 may be compared to nozzles as described above, wherein the airflow flowing from the auxiliary second space 15 may be compared to the motive fluid when guided via said openings 17 to the chimney 9 which may be compared to a diffuser, discharging the airflow to the surrounding atmosphere via said chimney 9. The suction effect caused by the ejector effect will thus be generated in, or in the vicinity of, the intake 1 1 of the chimney 9, wherein a venting of the first space 7 is provided by the ventilation device 3.

It should be noted that the term chimney 9 used for the ventilation device 3 of the invention is to be seen as a ventilation duct, mainly or purely for venting the first space 7 by means of guiding an airflow through the second space 15. When the ventilation device 3 is used for a vehicle 1 , as described in accordance with figure 1 , the chimney 9 of the ventilation device 3 is not to be viewed as the exhaust system of the engine 5 of the vehicle 1 . The exhaust system for the engine 5 may be incorporated with the chimney 9, but it may also be a regular exhaust pipe

transporting produced exhaust gases away from the engine to any suitable placement of said exhaust pipe. Such an exhaust pipe may further also be formed as a chimney, leading the exhaust gases upwards if so is desired. It should therefore be emphasized that the term chimney, when used in the description for the invention relates to a chimney 9 of a ventilation device 3.

Figure 2 schematically illustrates a perspective view of an auxiliary second space 15 of a ventilation device 3 according to the invention. The auxiliary second space 15 shown in figure 2 should be viewed as part of a ventilation device 3 which is arranged to a first space 7 under the auxiliary second space 15. In this example, the auxiliary second space 15 comprises a chimney 9 with an inlet 1 1 and an outlet 13, wherein the inlet 1 1 is designed to be arranged in fluid communication with the first space 7 for which the ventilation device 3 is meant to be used, wherein an airflow going through the auxiliary second space 15 and into the chimney 9 creates an ejector effect which drags air and thereby heat from said first space 7. The airflow guided by means of the ventilation device 3 is illustrated with arrows with solid lines 23 and the airflow flowing as a result of the ejector effect is illustrated with arrows with dotted lines 25. The chimney 9 of this example has a rectangular cross- sectional shape, but other shapes are also possible without deviating from the inventive concept of the invention. It should also be understood that the chimney 9 of this example is only shown extending in length along the auxiliary second space 15, but may extend further upwards positioning the outlet 13 higher, and may also extend downwards if the first space 7 is placed at a distance from the auxiliary second space 15. Generally the first space 7 is arranged directly under the auxiliary second space 15, to increase the effectiveness of the ejector effect provided by the ventilation device 3. The auxiliary second space 15 shown in this example further comprises a heat exchanger 27, which extends down into the first space 7. The heat exchanger 27 may further be part of a heat exchanger unit arranged to a device within the first space 7, wherein the heat exchanger 27 may be coupled to said heat exchanger unit by means of hoses or tubes or similar, as a way of transporting heat to the heat exchanger 27. The extension of the heat exchanger 27 down into the first space 7 are thus to be viewed merely as an illustration of heat being transferred from the first space 7 to the auxiliary second space 15. Thereby part of heat generated in the first space 7 is being removed by means of the heat exchanger 27 while at the same time more heat is being removed by means of the ejector effect provided by the ventilation device 3. Furthermore, the auxiliary second space 15 of figure 2 comprises four fans 21 , which fans 21 are arranged in an outer wall 29 of the auxiliary second space 15. The fans 21 sucks in air from a surrounding atmosphere, guiding said air through the auxiliary second space 15 and into the chimney 9 via a plurality of openings 17 arranged in a dividing wall 31 situated between the auxiliary second space 15 and the chimney 9. It should be realized that the number of fans 21 and the number of openings 17 may vary in different embodiments of the ventilation device 3, and may be chosen depending on factors such as the size of the

ventilation device 3. Furthermore, the fans 21 may also be placed anywhere within the auxiliary second space 15, wherein additional openings for intake of air may be arranged to the auxiliary second space 15 for intake of air from the surrounding atmosphere. The openings 17 arranged in the dividing wall 31 shown in figure 2 further comprises angled guide vanes 33, arranged at the bottom of each opening 17 and extending into the chimney 9 at an angle. The angled guide vanes 33 thereby guide the airflow upwards as it is passing through the openings 17. This provides an airflow which is guided in the right direction more effectively and lowers the risk of air passing through the openings 17 and going down towards the first space 7, which would be counter-effective in regards of the ejector effect. The angled guide vanes 33 may further have an end portion directed upwards the outlet of the chimney 9 further guiding the airflow upwards. Other shapes are also possible for the guide vanes 33, such as rounded shapes to guide the airflow along a curve of rounded guide vane 33. It should furthermore also be noted that the auxiliary second space 15 shown in figure 2 further comprises a ceiling and another outer wall, which are not shown in figure 2. The auxiliary second space 15 according to this embodiment of the auxiliary second space 15 is hence meant to be seen as a closed space. Said closed space is not being in fluid communication with the first space 7 or the environment except for the described at least one opening 17 and at least one fan 21 , with their respective openings for intake air. Thus, air is only entering the auxiliary second space 15 via the intake air openings and/or the at least one fan 21 . Said intake air enters from the surroundings and not from the first space 7. As should be realized, the ceiling and other outer wall are not being depicted to help the understanding of the perspective figure.

If the example of the auxiliary second space shown in figure 2 would to be used for a vehicle 1 as shown in figure 1 , the heat exchanger 27 and the fans 21 may be part of a heat exchanger unit of the engine 5 of the vehicle 1 . Thereby the heat exchanging provided by the heat exchanger unit which is commonly used for engines is provided while at the same time moving the fans of said heat exchanger unit to the auxiliary second space 15 which provides a better working environment for said fans. As the fans will operate in a non-engine room environment the working life of the fans may be extended and an efficient cooling is provided. However, it should be realized that the ventilation device 3 according to the invention may also be used to vent other types of first spaces 7 which may not be engine rooms, wherein fans 21 may still be provided to the auxiliary second space 15 to guide an airflow within said second space 15 and suck in cool air from a surrounding environment. Another example of first spaces 7 with ventilation needs may be a first space 7 containing hazardous chemicals, wherein fumes of said chemicals could have a negative impact of the fans 21 of the ventilation device 3. Thereby the ventilation device 3, by means of venting a first space 7 using an ejector effect, may provide an effective venting of said first space 7 using fans 21 but placing said fans 21 in a better working environment. For such an example the heat exchanger 27 shown in figure 2 may not be needed or desired and may simply not be present if heat is a non-issue for the ventilation device 3.

Figure 3 schematically illustrates a perspective view of an auxiliary second space 15 of a ventilation device 3, further comprising baffle plates 35, according to the invention. The auxiliary second space 15 shown in figure 3 can be viewed as similar to the auxiliary second space 15 shown in figure 2, further comprising another outer wall 29, in which a plurality of baffle plates 35 are arranged. The baffle plates 35 are arranged to be able to move between a closed state and an open state. The closed state prevents air from passing through outer wall openings 37 to which the baffle plates 35 are mounted. The open state, which is shown in figure 3, provides fluid communication with the surrounding atmosphere and the auxiliary second space 15. The baffle plates 35 are arranged to move to the open state when the pressure within the auxiliary second space 15 reaches a predetermined value. Said

predetermined value is based on an acceptable pressure for the airflow within the ventilation device 3 affecting the fans 21 guiding said airflow. If a too high pressure is reached within the auxiliary second space 15 and/or the chimney 9, the desired ejector effect might be negatively affected or in worst case negated. Further, if the ventilation device 3 comprises a heat exchanger as depicted in the example of figure 2, the heat exchange within said heat exchanger 27 may also be negatively affected by the reduced flow of air due to a too high pressure within the auxiliary second space 15. Furthermore, depending on the type of fan 21 , or fans 21 , used in the ventilation device 3, said fan 21 , or fans 21 , might also be subjected to an increased ware and hence a lesser working lifespan if the pressure within the ventilation device 3 reaches too high values. The baffle plates 35 are arranged in the outer wall 29 to alleviate such a situation from arising. The baffle plates 35 shown in figure 3 are spring-loaded by means of springs 39 arranged to bias the baffle plates 35 to be in the closed state when acceptable pressure levels are present within the auxiliary second space 15 and in the chimney 9. Said springs 39 have specific spring forces holding the baffle plates 35 closed based on the design parameters of said springs 39. When/if a too high pressure is reached within the auxiliary second space 15, the force based on said pressure will overcome the spring forces of the springs 39 release the bias towards the closed state which will automatically move the baffle plates 35 to the open state. In such a situation the pressure will be equalized with the pressure of the outside atmosphere which in turn alleviates the build-up of pressure within the ventilation device 3. Additional baffle plates 35 may also be placed in an outer wall of the chimney if it is desired to equalize a build-up of pressure within the chimney 9 directly. The baffles plates 35 may also be mounted with an actuating device (not shown), which actuating device moves the baffle plates 35 between the open and closed state. The actuating device may be any known type of actuating device such as a motorized piston or similar. The actuating device may then be controlled by a driver of the vehicle directly or be operated on basis of a measured pressure value. The baffle plates 35 may be mounted with springs 39, or with actuating devices, or a combination of both, if desired. Thereby a versatile ventilation device 3 is provided, wherein the pressure can be equalized both by automatic means and by user controlled means. Furthermore, the baffle plates 35 of the ventilation device 3 may be designed to be fixed in the open state wherein the pressure within the auxiliary second space 15 instead is controlled by the operation of the fans 21 .

Figure 4 schematically illustrates a cross-sectional side view of a ventilation device 3 according to the invention. This schematic illustration of a ventilation device 3 comprises a first space 7, preferably being viewed as an engine room of a vehicle 1 with an engine 5 situated therein. The engine 5 generates heat when operated giving rise to a need to vent said heat from said first space 7. The first space 7 comprises an air intake opening 19, wherein air is sucked into the first space 7 by means of a pressure difference between said first space 7 and a surrounding atmosphere, outside of the vehicle 1 . The air intake opening 19 may be placed anywhere in an outer wall 29 of the first space 7. The placement of the air intake opening 19 depicted in figure 4 is merely placed at its location as a convenience in regards to viewing the figure in an easy way. Preferably the placement of the air intake opening 19 is situated in, or in the proximity to, the opposite corner of the first space 7 in regards to the chimney 9 so as to achieve maximum cooling on the engine 5 by means of the airflow flowing through the first space 7. The first space 7 may further comprise a plurality of air intake openings 19, and the example depicted in figure 4 should not be viewed as a restriction of the invention. The engine 5 in the first space 7 further comprises a heat exchanger unit 41 with a heat exchanger 27 which extends up into the auxiliary second space 15, situated directly on top of the first space 7. The ventilation device 3 may however comprise a plurality of heat exchangers 27 and/or heat exchanger units 27 without deviating from the inventive concept of the invention. The heat exchanger unit 41 further comprises a fan 21 which cools the engine by means of cooling a coolant which circulating within the heat exchanger 27 and the engine 5 as well as guiding cool intake air from a surrounding atmosphere into the auxiliary second space 15. Said fan 21 then guides the intake air through the auxiliary second space 15 and into the chimney 9, arranged adjacent the auxiliary second space 15, via a plurality of openings 17 provided with angled guide vanes 33 to guide the airflow in a direction towards the outlet 13 of the chimney 9. Thereby the airflow creates an ejector effect in the inlet 1 1 of the chimney 9 by means of the pressure difference created by the directed air guided away from the first space 7. The example of the ventilation device 3 shown in figure 4 further comprises a sensor 43, arranged to determine the pressure within the auxiliary second space 15. Said sensor 43 can be viewed as any type of pressure sensor known in the art. Said sensor 43 can measure the pressure within the auxiliary second space 15 to determine if baffles plates (not shown in figure 4) should be moved to an open state by means of an actuating device (as described with reference to figure 3) and/or as a means to monitor the internal pressure of the ventilation device 3. Additional sensors may also be arranged in the chimney 9 and/or the first space 7 as a means of closely monitoring the internal pressures of each individual space 7, 9, 15 of the ventilation device 3, wherein baffles plates 35 may be opened or closed to control said internal pressures.

Figure 5 shows a flowchart of a method for venting a first space 7 according to the invention. The method is performed by using a ventilation device 3 according to the description accompanying figure 4. Wherein the ventilation device 3 comprises a chimney 9 extending from the first space 7, the chimney 9 comprising an inlet 1 1 and an outlet 13, wherein the inlet 1 1 is arranged in fluid communication with the first space 7 and the outlet 13 is in fluid communication with a surrounding atmosphere. The ventilation device 3 further comprises an auxiliary second space 15, the second space 15 being arranged adjacent the chimney 9 and being in fluid communication with the chimney 9 by means of at least one opening 17. The method shown in the flowchart in figure 5 comprises the steps of: a) guiding an airflow from the auxiliary second space 15 to the surrounding atmosphere via the chimney 9 so as to cause an ejector effect in the chimney 9 which vents the air in the first space 7, b) opening at least one baffle plate 35 to equalize the pressure within the auxiliary second space 15, and c) which is performed after a) and before b) determining the pressure of the auxiliary second space 15 by means of the sensor 43. According to different embodiments of the invention, the method may be performed in different ways. The method described above in accordance with figure 5 describes a method wherein a first space 7 is vented by means of step a), and where the risk of a build-up of pressure is monitored by means of step c) and alleviated by means of step b).

However, another embodiment of the method may be performed by using an embodiment of a ventilation device 3 as shown in figure 2, wherein only step a) is performed so as to purely vent a first space 7 by means of creating an ejector effect in a chimney 9 arranged in fluid communication with said first space 7. Furthermore, yet another embodiment of the method may be performed by using an embodiment of a ventilation device 3 as shown in figure 3, wherein step a) and b) are performed to vent a first space 7 and automatically open baffles plates 35 which are spring- loaded with a specific force, corresponding to a predetermined allowed pressure within the embodiment of the ventilation device 3. As should be realized, the components and features specified above may within the framework of the invention be combined between the different embodiments specified.