Ventilation device for building services engineering and methods for installing or maintaining a ventilation device

Description

[0001] The invention relates to a ventilation unit for building services, comprising a housing, at least one supply air and / or exhaust air duct arranged in the housing for guiding a supply air or exhaust air flow through the housing, at least one radial fan with backward-curved blades arranged in the supply air and / or exhaust air duct for generating the supply air or exhaust air flow, and at least one differential pressure sensor arranged within the housing, which is configured to detect pressure conditions at at least two measuring points in the housing, on the basis of which a supply air or exhaust air volume flow through the supply air and / or exhaust air duct is controlled. Furthermore, the invention relates to a method for mounting a ventilation unit.

[0002] Ventilation units for building services engineering are known in the prior art, in particular residential ventilation units used for supplying and extracting air from rooms in buildings. These units facilitate a controlled exchange of air in the rooms, either continuously or alternately at predetermined intervals, replacing indoor air with fresh outdoor air. The ventilation units have an air-conducting connection between the room(s) in the building and an exterior area. Some ventilation units have a combined supply and exhaust air duct for guiding the supply or exhaust air flow through the housing. Other ventilation units have separate supply and exhaust air ducts within the housing for guiding the supply and exhaust air flow.

[0003] Highly efficient ventilation units, especially residential ventilation units, utilize radial fans with backward-curved blades to generate the supply or exhaust airflow. Due to the minimal air deflection, resulting in lower shock losses, these fans consume less power during operation. Furthermore, these efficient units feature constant volume flow control to ensure that the required airflow is maintained despite changing operating conditions, such as increasing filter contamination or system-related factors like additional accessories like silencers, or duct lengths adapted to the installation situation.

[0004] However, constant volume flow control using the standard radial fan characteristic curve is not feasible for radial fans with backward-curved blades. Differential pressure measurement is typically used for volume flow control in such fans. During differential pressure measurement, pressures within the housing are measured at at least two points using a differential pressure sensor. The resulting differential pressure, which is preferably proportional to the volume flow rate in the supply or exhaust air duct, serves as the control variable for the supply or exhaust air volume flow rate through the duct. Accurate measurement of the differential pressure requires precise positioning of the differential pressure sensor to avoid potential influences such as mounting tolerances that could negatively impact the measurement result.Furthermore, it is also crucial that such a differential pressure sensor is protected from any particles carried along with the supply or exhaust air flow, such as dust or moisture, in order to keep deviations in the pressure measurement as low as possible.

[0005] US 2011 / 217182A1 relates to a blower unit comprising a centrifugal blower coupled to a drive unit, a control unit operationally coupled to the drive unit, an inlet piece forming an inlet channel to the centrifugal blower, the inlet channel having an end facing the centrifugal blower, and an outlet channel, the inlet piece being provided with a first pressure gauge and a second pressure gauge, the second pressure gauge being located at a distance from the end of the inlet channel facing the centrifugal blower, and the control unit being configured to measure a pressure difference between the first and second pressure gauges and to control the centrifugal blower depending on the measured pressure difference.

[0006] DE 44 07 969 A1 discloses a fan for supplying and extracting air into and from rooms, preferably forced-ventilated, and in particular windowless, rooms, with an air filter associated with the fan. It is provided that a differential pressure sensor (15) is arranged in or on a fan housing (2) of the fan (1), which measures the air pressure both before and after the air filter (22) and, if a predefinable pressure difference is exceeded, triggers a signaling device (7) as an indication of contamination of the air filter (22) and / or switches off the fan (1).

[0007] The invention was therefore based on the objective of avoiding any disadvantages that may occur during differential pressure measurement in a ventilation unit and, in particular, of demonstrating a ventilation unit for building services, especially a residential ventilation unit, as well as a method for mounting or maintaining a ventilation unit, on or by means of which the mounting of the differential pressure sensor is simplified, despite a continued reliable and, above all, precise differential pressure measurement, wherein, in particular, the differential pressure sensor can be easily removed or replaced if necessary.

[0008] The invention solves the underlying problem according to a first aspect by means of a ventilation device for building services of the aforementioned type with the features according to claim 1. In particular, the ventilation device is characterized in that the housing is formed from at least a first housing part and a second housing part corresponding to the first housing part and forming a connection area, wherein the differential pressure sensor is arranged in the connection area of ​​the first and second housing parts in a receiving space defined by at least one of the housing parts and unaffected by the supply or exhaust air flow.

[0009] The invention pursues the approach of arranging the differential pressure sensor, instead of at an arbitrary location within the housing, directly in the junction area of ​​two housing parts forming the housing, in a receiving chamber not directly influenced by the supply or exhaust air flow. This protects the differential pressure sensor and, ideally, isolates it from the supply or exhaust air flow and any particles carried within it. The receiving chamber for the differential pressure sensor is preferably designed as a recess directly adjacent to the junction area where the two housing parts are in direct or indirect contact. While the receiving chamber for the differential pressure sensor is preferably unaffected by, or not directly subjected to, the volume flow through the supply and / or exhaust air duct, it nevertheless has a pressure-conducting connection to the supply and / or exhaust air duct.This ensures essentially continuous, stable pressure conditions within the housing for the differential pressure sensor. The differential pressure sensor can, for example, be mounted on a bracket formed within the housing.

[0010] Preferably, the control or adjustment of the volume flow generated by the radial fan within the supply air and / or exhaust air duct is carried out on the basis of the pressure conditions detected by the differential pressure sensor at the two measuring points in the housing by means of a control device on the ventilation unit that is connected to the differential pressure sensor and the radial fan in a signal-conducting manner.

[0011] The housing for the differential pressure sensor preferably has a connection to a section of the supply or exhaust air duct. Thus, a first measuring point is provided in the housing for detecting the pressure using the differential pressure sensor. While a lower pressure is measured at this point compared to the surroundings, it is taken from a flow-stabilized area of ​​the housing, unaffected by flow effects or turbulence. This ensures a sufficiently large pressure difference to a second measuring point of the differential pressure sensor, where the pressure in the supply or exhaust air stream with maximum flow is preferably measured. The differential pressure sensor housed within the housing is therefore connected to a measuring line at only one of its measuring terminals. This line transmits the required differential pressure to the other (second) measuring point.Based on the sufficiently large pressure difference, precise control of the volume flow at the radial fan is achieved.

[0012] A further development of the invention provides that the receiving chamber for the differential pressure sensor is arranged above a receiving chamber for the radial fan, which are preferably formed in different housing parts. By arranging the differential pressure sensor above the receiving chamber for the radial fan, the latter is positioned at a higher location within the housing, so that a measuring line leading towards the differential pressure sensor is routed upwards. Any condensate that forms inside the housing does not reach the differential pressure sensor via the lines, but is instead directed away from the sensor. Preferably, the receiving chamber for the differential pressure sensor in the upper (second) housing part forms a cavity closed at the top, which is only accessible from the underside of the second housing part. The receiving chamber for the radial fan is preferably formed in the lower (first) housing part.

[0013] In a further embodiment, the connection area between the first and second housing parts is located directly above the radial fan arranged within the housing. By positioning the connection area immediately above the space for the radial fan, a structurally simple separation of the ventilation unit's housing is achieved. In particular, this simplifies the assembly of the individual housing parts with the components to be fitted to them. Access to the space for the differential pressure sensor is from the underside of the upper (second) housing part. The differential pressure sensor is therefore located directly above the radial fan. In one embodiment, the retaining element located in the connection area of ​​the housing parts can, for example, have direct contact with air-conducting sections of the space containing the radial fan or with the radial fan itself.

[0014] According to a preferred embodiment of the ventilation unit, the differential pressure sensor is arranged on a mounting bracket separate from the housing parts, which is located in the connection area between the first and second housing parts. Instead of mounting the differential pressure sensor directly on a housing part, it is placed on a separate component. For maintenance purposes, the differential pressure sensor can be easily removed from the mounting bracket in the connection area between the housing parts of the ventilation unit. The differential pressure sensor is mounted on the mounting bracket in such a way that it projects into the special receiving space defined by at least one of the housing parts, thus remaining securely and, above all, protected within the fan housing. The mounting bracket is arranged between the first and second housing parts, with preferably portions of the mounting bracket being in contact with both the first and second housing parts.

[0015] Preferably, the retaining element for the differential pressure sensor is designed as a separating element for at least some areas of the housing parts to be joined together. The retaining element thus directly separates areas of the otherwise connected housing parts from one another, with the housing parts preferably acting on the retaining element from opposite sides. In a preferred embodiment, the retaining element, together with the differential pressure sensor attached to it, is held in position by the housing parts acting on it. Preferably, the housing parts in the connection area have corresponding surface sections that correspond to the retaining element and define the position of the retaining element in the connection area relative to the housing parts.This simplifies the installation / maintenance of the ventilation unit, as the mounting part with the differential pressure sensor attached to it is installed in the correct position thanks to the predefined alignment.

[0016] A further development of the ventilation unit provides that the retaining element has a substantially flat surface element extending along the connection area, which has one or more recesses cooperating with the supply or exhaust air duct in the housing. In one embodiment, the retaining element extends only over a relatively small section of the connection area; in an alternative embodiment, it can extend between the first and second housing parts up to the outer dimensions of the housing formed by the housing parts. In particular, the surface element of the retaining element has specially designed material projections or formed recesses on its opposite sides, which permit only a predetermined installation position of the retaining element, including the differential pressure sensor, on, for example, the lower (first) housing part.The upper (second) housing part is placed onto the lower housing part and the mounting bracket resting on it. The surface element has, for example, recesses that correspond to the supply or exhaust air duct running through the housing.

[0017] According to a preferred embodiment, the recess(s) has / have a material rib projecting approximately perpendicularly from the surface element, which preferably aligns with the wall of the supply or exhaust air duct. Thus, the transition between the housing parts and the intermediate retaining element in the area of ​​the supply and / or exhaust air duct is seamless, which facilitates the smooth flow of the supply or exhaust air within the duct. Preferably, the material rib projects from both sides of the surface element in the area of ​​each recess. The material rib also engages in recesses formed in the housing parts in the area of ​​the supply and / or exhaust air ducts.Preferably, the housing parts and the retaining part for the pressure sensor are joined together in a material-bonded manner, so that a seal is created in the connection area of ​​the components that are in direct contact with each other (first and second housing part and retaining part).

[0018] Preferably, the retaining element includes a receiving section for the differential pressure sensor, in which the differential pressure sensor is reversibly and detachably mounted. This simplifies the assembly and disassembly of the differential pressure sensor on the retaining element itself and on a housing of the ventilation unit that accommodates the retaining element together with the differential pressure sensor.

[0019] According to a preferred embodiment of the ventilation device, the receiving section has an elastically deformable locking element that can be brought into a holding connection with the differential pressure sensor, enabling a reversibly detachable positive-locking connection of the differential pressure sensor to the receiving section. By providing an elastically deformable locking element, for example, a spring or snap hook on the receiving section, a structurally simple method for achieving a reversibly detachable locking of the differential pressure sensor to the holding part, particularly to its receiving section, is achieved. The differential pressure sensor can be released from the receiving section on the holding part, particularly without tools, by moving the locking element out of its locked position. Preferably, the receiving section has an insertion area and a locking area for the sensor.The locking area for the differential pressure sensor, in particular for the circuit board that receives the differential pressure sensor, preferably runs parallel to the surface element of the retaining part. The locking area and the insertion area for inserting the differential pressure sensor into the receiving section are aligned at an angle of approximately 100 to approximately 170 degrees to each other.

[0020] According to a preferred embodiment, the differential pressure sensor has at least two measuring ports, with only one of the measuring ports being connected to a measuring line extending, in particular, into the intake area of ​​the radial fan. Due to the protected mounting of the differential pressure sensor in a flow-stabilized area above the radial fan, one measuring port directly measures the pressure in the receiving chamber. The other measuring port is connected to a measuring line that extends into the intake area of ​​the radial fan and measures the static pressure there, which is lower compared to the pressure in the receiving chamber. Based on the determined differential pressure and other factors and operating conditions, such as the fan speed, the volume flow generated by the radial fan is calculated and, if necessary, adjusted or controlled.By placing the differential pressure sensor directly above the radial fan, the measuring line used to detect the pressure in the intake area of ​​the radial fan can have an advantageously short length, which minimizes inaccuracies in measuring the pressure conditions in the housing.

[0021] In one embodiment of the invention, the measuring line, which runs from one measuring port on the differential pressure sensor to the intake area of ​​the radial fan, is guided through a recess in the mounting bracket for the differential pressure sensor. This prevents constriction or kinking, particularly if the measuring line is designed as a flexible hose, which would lead to pressure losses in the measuring line and thus to a distortion of the measurement results.

[0022] According to one embodiment, at least one of the housing parts is made of at least partially foamed plastic, in particular expanded polystyrene (EPS) or expanded polypropylene. Preferably, the entire housing, including its first and second housing parts, consists of a foamed plastic. The multi-part housing simplifies its manufacture, particularly the formation of the supply and / or exhaust air ducts or the receiving spaces for the differential pressure sensor and the radial fan within the housing parts. Furthermore, the necessary recesses or protrusions for the retaining element that interacts with the housing parts can be more easily created on corresponding surfaces forming the connection area of ​​the housing parts.

[0023] According to a second aspect, the problem underlying the invention is solved by a method for mounting a ventilation device, in particular a ventilation device according to claim 1.In particular, the method is characterized by the following steps: providing a housing consisting of at least two housing parts and at least one differential pressure sensor; electrically connecting the differential pressure sensor to a control unit of the ventilation device using at least one connecting cable; joining the two housing parts together, wherein a receiving space for the differential pressure sensor, unaffected by the supply and / or exhaust air flow and defined by at least one of the housing parts, is formed; and positioning the differential pressure sensor in the receiving space relative to one of the housing parts in the connection area of ​​the housing parts to each other, preferably using a retaining element to be arranged in the connection area, on which the differential pressure sensor is particularly reversibly detachable.

[0024] The method according to the invention takes advantage of the same benefits as the ventilation device according to the invention described in the first aspect. The preferred embodiments and further developments described in relation to the first aspect are also preferred embodiments of the method according to the invention, provided they do not fundamentally contradict each other, which is why reference is made to the above statements to avoid repetition.

[0025] The invention is described in more detail below with reference to a preferred embodiment of a ventilation device and the accompanying figures. These figures show: Fig. 1 a schematic spatial view of a ventilation device according to the invention in section; Fig. 2 a schematic view of the ventilation device according to Fig. 1 differential pressure sensor used; Fig. 3 a perspective view of one in the connection area of ​​the housing parts of the ventilation unit according to Fig. 1arranged holding part; Fig. 4 an enlarged, schematic sectional view of a receiving section on the holding part according to Fig. 3 ; Fig. 5 a further schematic, spatial partial view of the ventilation device according to the invention Fig. 1 , and Fig. 6 another spatial sectional view of the ventilation unit according to Fig. 1 .

[0026] Fig. 1 Figure 1 shows a cross-sectional view of a ventilation unit 100 according to the invention, which is used for supplying and / or extracting air from rooms in a building not shown in detail. The ventilation unit 100 has a housing 102 in which at least one supply air duct 104 and one exhaust air duct 106 run. A supply air flow 108 is directed into the building, in particular its rooms, through the supply air duct 104, and an exhaust air flow 110 is directed from the rooms to the outside of the building through the exhaust air duct.

[0027] The housing 102 is multi-part and comprises a first housing part 112 and a second housing part 114. The first housing part 112 forms a lower housing part, and the second housing part 114 forms the upper housing part of the ventilation unit 100. A radial fan 116, which has a fan wheel 118 with backward-curved blades 120, is arranged in the supply air duct 104 of the housing 102, in particular in a section of the supply air duct 104 in the first housing part 112. Such a radial fan 116 with backward-curved blades 120 is used for the efficient generation of a volume flow in modern ventilation units.

[0028] The exhaust air duct 106, shown only partially, in the form of a bypass channel that can be fluidly coupled to the exhaust air duct 106, is also associated with a radial fan (not shown in detail) for generating a volume flow within the exhaust air duct 106 of the ventilation unit 100. The radial fan arranged in the exhaust air duct 106 also has a fan wheel with backward-curved blades. The radial fan arranged in the exhaust air duct 106 is identical in design to the radial fan 116 arranged in the supply air duct 104, or is arranged in a similar form in the first housing part 112.

[0029] The radial fan 116 is arranged in a receiving chamber 122 in the first, lower housing part 112. The receiving chamber 122 and the radial fan 116 are formed or arranged directly below a connecting area 124 that separates the first housing part 112 and the second housing part 114. The connecting area 124 separates the first and second housing parts 112, 114 from each other along a substantially horizontal plane E.

[0030] Within the housing 102, in particular in a receiving chamber 126, a differential pressure sensor 128 is further arranged, which is positioned near or in the connection area 124 of the first and second housing parts 112, 114. The differential pressure sensor 128 is configured to detect pressure conditions at at least two measuring points 132, 132', whereby, based on the pressures detected at the measuring points 132, 132', a supply air or exhaust air volume flow rate flowing through the supply air duct 104 and / or the exhaust air duct 106 is set or controlled. The adjustment of the supply air or exhaust air volume flow rate is achieved in particular by influencing the rotational speed of the radial fan 116. For this purpose, the radial fan 116 has a drive unit (not shown in detail) in the form of an electric motor.

[0031] The receiving chamber 126, which accommodates the differential pressure sensor 128, is arranged within the housing 102 in such a way that it is unaffected by the supply or exhaust air flow 108, 110. However, the receiving chamber 126 for the differential pressure sensor 128 has a connection to a section of the supply or exhaust air duct 104, 106, which carries the supply or exhaust air flow 108, 110.

[0032] The receiving chamber 126 for the differential pressure sensor 128 is arranged above the receiving chamber 122 for the radial fan 116, with both receiving chambers 122, 126 being formed in different housing parts 112, 116. As shown from Fig. 1 Furthermore, it can be seen that the connection area 124 lies exactly above the radial fan 116 arranged in the housing 102.

[0033] Fig. 2Figure 1 shows an embodiment of the differential pressure sensor 128 used in the receiving chamber 126, which is arranged on a printed circuit board 130, also referred to as a circuit board. The differential pressure sensor 128 has two measuring connections 134, 136. By arranging the differential pressure sensor 128 within the flow-stabilized receiving chamber 126, a pressure measurement can be taken directly on-site in the receiving chamber 126 using the measuring connection 134. A first measuring point 132 is thus located within the receiving chamber 126, with the measuring connection 134 precisely detecting the static pressure present in the receiving chamber 126.

[0034] In the embodiment shown, the differential pressure sensor 128 is arranged on a retaining element 128, which is separate from the housing parts 112 and 114 and is received in the connection area 124 between the first and second housing parts 112 and 114. The retaining element 128 acts as a separating element between the housing parts 112 and 114 of the ventilation unit 100. The retaining element 128 separates at least areas of the mutually facing surfaces of the housing parts 112 and 114 to be joined.

[0035] As from Fig. 3As can be seen, the retaining part 138 has a substantially flat surface element 140 extending along the connection area 124. The surface element 140 defines the connection area 124 and has opposing contact surfaces 142, 144, which directly contact the first and second housing parts 112, 114. Recesses 146, 148 are formed in the surface element 140, which correspond to the supply and exhaust air ducts 104, 106 in the housing 102. Material ribs 150, 152 extend along the entire circumference of the recesses 146, 148, projecting approximately perpendicularly from the surface element. In the embodiment shown here, as in conjunction with Fig. 1 As can be seen, these were flush with the walls of the supply and exhaust air ducts 104, 106.

[0036] As from the Figures 3 and 4As can be seen, a receiving section 154 for the differential pressure sensor 128 is provided on the retaining part 138, by means of which the differential pressure sensor 128, in particular its circuit board 130, is reversibly and detachably received. In the embodiment shown here, the receiving section 154 has, by way of example, an insertion area 156, through which the circuit board 130 together with the differential pressure sensor 128 is inserted at an insertion angle α, relative to the surface element 140, in a range of 10° to 80°, preferably 45°.

[0037] The receiving section 154 further comprises a locking area 158 for the circuit board 130 together with the differential pressure sensor 128, which is aligned approximately parallel to the surface element 140 of the holding part 138. The insertion area 156 on the receiving section 154 and the locking area 158 for the sensor are aligned at an angle of approximately 100° to approximately 170° to each other.

[0038] To lock the circuit board 130 of the differential pressure sensor 128 in the locking area 158, an elastically deformable locking element 160 is provided on the receiving section 154. This locking element can be brought into a holding connection with the circuit board 130, creating a reversibly detachable positive-locking connection with the sensor. If necessary, for example in the event of a defect, the differential pressure sensor 128 can thus be easily and, above all, without tools removed from the connection area of ​​the housing parts 112, 114, particularly at the retaining element 138, and replaced.

[0039] The Figures 5 and 6 show similar to Fig. 1 Sectional views of the ventilation unit 100, wherein, to illustrate the structure of the ventilation unit 100, the sections run in different planes of the housing 102. At least one of the housing parts 112, 114 is at least partially made of a foamed plastic, in particular expanded polystyrene or propylene.

[0040] Fig. 5The figure shows the radial fan 116 in its completed configuration, so that in particular an intake area 162 of the radial fan 116 is also visible. As shown in the figure. Fig. 5 As can be seen, a measuring line 164 ends in the intake area 162 of the radial fan 116, which runs from the intake area 162 towards the differential pressure sensor 128 located in the receiving chamber 122 ( Fig. 1 ) is led. The end of the measuring line 164 assigned to the intake area 162 forms the second measuring point 132', spaced apart from the first measuring point 132, for recording the pressure conditions in the housing 102.

[0041] Based on the pressures recorded in the recording chamber 122 and at the intake area 162, the differential pressure measurement is carried out by the differential pressure sensor 128, whereby, based on the pressure difference, which is proportional to the volume flow generated by the radial fan 116, the volume flow at the radial fan 116 is adjusted by adjusting the speed of the fan wheel 118.

[0042] Identical components are marked with the same reference symbols. Reference symbol list

[0043] 100 Ventilation unit 102 Housing 104 Supply air duct 106 Exhaust air duct 108 Supply air flow 110 Exhaust air flow 112 First housing part 114 Second housing part 116 Radial fan 118 Fan wheel 120 Blades 122 Receiving chamber 124 Connection area 126 Receiving chamber 128 Differential pressure sensor 130 Circuit board 132, 132' Measuring point 134, 136 Measuring connection 138 Retaining part 140 Surface element 142, 144 Mounting surface 146, 148 Recess 150, 152 Material web 154 Receiving section 156 Insertion area 158 Locking area 160 Latching part 162 Intake area 164 Measuring line Level α Insertion angle β Alignment angle

Claims

1. Ventilation unit (100) of the building services, comprising a casing (102), at least one supply air and / or extract air duct (104, 106) arranged in the casing (102) for guiding a supply air or extract air flow (108, 110) through the casing (102), at least one radial fan (116) with backward-curved blades (120) arranged in the supply air and / or extract air duct (104, 106) for generating the supply air or extract air flow (108, 110), and at least one differential pressure sensor (128) arranged within the casing (102), which is set up to detect pressure ratios at at least two measuring points (132, 132') in the casing (102), on the basis of which a supply air or extract air volume flow flowing through the supply air and / or extract air duct (104, 106) is controlled, characterised in that the casing (102) is formed from at least a first casing part (112) and a second casing part (114) corresponding to the first casing part (112) and forming a connection area (124), wherein the differential pressure sensor (128) is arranged in the connection area (124) of the first and second casing parts (112, 114) in a receiving space (126) which is unaffected by the supply air or extract air flow (108, 110) and is defined by at least one of the casing parts (112, 114).

2. The ventilation unit according to claim 1, characterised in that the receiving space (126) for the differential pressure sensor (128) has a connection to a section of the supply air or extract air duct (104, 106) carrying the supply air or extract air flow (108, 110).

3. The ventilation unit according to claim 1 or 2, characterised in that the connection area (124) separates the first and second casing parts (112, 114) from one another along a substantially horizontally extending plane (E), wherein the radial fan 116 is arranged in a receiving space (122) in the first lower casing part (112), and the receiving space (126) for the differential pressure sensor (128) is arranged above the receiving space (122) for the radial fan (116), wherein the receiving spaces (122, 126) are preferably formed in different casing parts (112, 114).

4. The ventilation unit according to claim 3, characterised in that the connection area (124) is formed exactly above the radial fan (116) arranged in the casing (102).

5. The ventilation unit according to any one of the preceding claims, characterised in that the differential pressure sensor (128) is arranged on a retaining part (138) which is separate from the casing parts (112, 114) and is mounted in the connection area (124) between the first and second casing parts (112, 114).

6. The ventilation unit according to claim 5, characterised in that the retaining part (138) for the differential pressure sensor (128) is provided as a separating part for at least areas of the casing parts (112, 114) of the casing (102) that are to be joined together.

7. The ventilation unit according to claim 5 or 6, characterised in that the retaining part (138) has a substantially flat surface element (140) extending along the connection area (124), which has one or more recesses (146, 148) cooperating with the supply air or extract air duct (104, 106) in the casing (102).

8. The ventilation unit according to claim 7, wherein the recess(es) (146, 148) comprise(s) a material strip (150, 152) projecting approximately vertically from the surface element (140), which is preferably aligned with the wall of the supply air or extract air duct (104, 106).

9. The ventilation unit according to any one of the preceding claims 5 to 8, characterised in that the retaining part (138) comprises a receiving section (154) for the differential pressure sensor (128), on which the differential pressure sensor is mounted in a reversibly releasable manner.

10. The ventilation unit according to claim 9, wherein the receiving section (154) has an elastically deformable latching part (160), which can be brought into a retaining operative connection with the differential pressure sensor (128), for a reversibly releasable positive-locking connection with the receiving section (154).

11. The ventilation unit according to any one of the preceding claims, characterised in that the differential pressure sensor (128) has at least two measuring connections (134, 136), wherein only one of the measuring connections (134, 136) is connected in an air-conducting manner to a measurement cable (164) extending in particular into the intake area (162) of the radial fan (116).

12. The ventilation unit according to any one of the preceding claims, characterised in that at least one of the casing parts (112, 114) is partially formed from foamed plastic, in particular expanded polystyrene.

13. Method for installing a ventilation unit (100), in particular a ventilation unit according to claim 1, comprising the steps of: - Providing a casing (102) consisting of at least two casing parts (112, 114) and at least one differential pressure sensor (128); - Electrical connection of the differential pressure sensor (128) to a controller of the ventilation unit (100) using at least one connecting cable; - Joining the two casing parts (112, 114) together, wherein a receiving space (126) defined by at least one of the casing parts (112, 114) and unaffected by the supply air or extract air flow (108, 110) is formed for the differential pressure sensor (128), and - Positioning of the differential pressure sensor (128) in the receiving space (128) relative to one of the casing parts (112, 114) in the connection area of the casing parts (112, 114) to one another, preferably using a retaining part (138) which is to be arranged in the connection area (124) and on which the differential pressure sensor (128) is mounted, in particular in a reversibly releasable manner.