Suction apparatus having a volumetric flow measuring device

Abstract

The invention relates to a suction apparatus (10) having a suction apparatus housing (11), in which a dust collection chamber (14) for collecting dust (ST) and a suction unit (20) for generating a suction flow (S) are arranged, wherein the suction apparatus (10) has a suction inlet (15) through which the suction flow (S) can flow into the dust collection chamber (14), and a suction flow outlet (S) through which the suction flow (S) can flow out of the suction apparatus housing (11), the suction unit (20) being arranged between the suction inlet (15) and the suction flow outlet (63), at least one filter element (30) for separating dust (ST) out of the suction flow (S) being arranged between the suction unit (20) and the dust collection chamber (14), and the suction unit (20) being arranged in a flow channel (45) between the at least one filter (30) and the suction flow outlet (63). The suction apparatus (10) has a volumetric flow measuring device (100) for ascertaining a volumetric flow value (V) of the suction flow (S), which volumetric flow measuring device has a flow pressure sensor (101) for ascertaining a flow pressure value (SD), which flow pressure sensor is fluidically connected to the flow channel (45) in such a way that, when the suction unit (20) is in operation, the suction flow (S) acts on the flow pressure sensor (101) in order to generate a flow pressure. According to the invention, an atmospheric pressure value (AD) is ascertained, the atmospheric pressure value (AD) representing an atmospheric pressure in the surroundings of the suction device (10). The volumetric flow measuring device (100) is configured to ascertain a volumetric flow value (V) representing a volumetric flow of the suction flow (S) on the basis of a difference between the flow pressure value (SD) and the atmospheric pressure value (AD).

Description

[0001] August 22, 2025

[0002] Festool GmbH, Wertstraße 20, 73240 Wendlingen

[0003] Suction unit with a volume flow measuring device

[0004] The invention relates to a vacuum cleaner with a vacuum housing in which a dust collection chamber for collecting dust and a suction unit for generating a suction flow are arranged, wherein the vacuum cleaner has a suction inlet through which the suction flow can enter the dust collection chamber and a suction flow outlet through which the suction flow can flow out of the vacuum housing, wherein the suction unit is arranged between the suction inlet and the suction flow outlet and at least one filter element for removing dust from the suction flow is arranged between the suction unit and the dust collection chamber, and wherein the suction unit is arranged in a flow channel between the at least one filter and the suction flow outlet, wherein the vacuum cleaner has a volume flow measuring device for determining a volume flow value of the suction flow, wherein the volume flow measuring device has a flow pressure sensor for determining a flow pressure value.wherein the flow pressure sensor is flow-connected to the flow channel in such a way that, when the suction unit is in operation, the suction flow acts on the flow pressure sensor to generate a flow pressure.

[0005] Generally, it is advantageous to measure the volume flow rate of a vacuum cleaner. This ensures, for example, that the suction flow rate is always sufficiently high to guarantee reliable dust extraction during the operation of a hand-held power tool or other machine tool. Otherwise, there is a risk of health problems for the users of the vacuum cleaner and the machine tool.

[0006] P 31363 / PCT

[0007] 22 August 2025 A volume flow measurement in a vacuum cleaner is described, for example, in WO 2024 / 057180 A1 or DE 10 2018 204 172 A1.

[0008] It is therefore the object of the present invention to provide the most reliable and accurate possible volumetric flow measurement of the suction flow.

[0009] To solve the problem, a volume flow measuring device of the type mentioned above is provided in such a way that the flow pressure sensor is arranged in the flow channel of the suction device and the volume flow measuring device has at least one flow guide body for guiding the suction flow with respect to the flow pressure sensor, in particular past the flow pressure sensor.

[0010] The underlying principle is that the volumetric flow measurement device generates reliable readings using simple pressure sensors suitable for measuring static pressures. The flow pressure sensor is advantageously a barometric sensor, which is therefore also suitable for measuring atmospheric pressure, for example.

[0011] A complex and often expensive differential pressure sensor is not necessary. In principle, a differential pressure sensor could also be used as a pressure sensor.

[0012] Advantageously, the volume flow value representing the suction flow is determined using pressure values, where one pressure value is the flow pressure value, which is determined during operation, i.e., with the suction flow running. Atmospheric pressure is advantageously used as the reference value for this flow pressure value. The atmospheric pressure value can be determined, for example, by the flow pressure sensor itself, such as before the start of suction operation, i.e., when the flow pressure sensor is only exposed to atmospheric pressure and not to pressure resulting from the suction flow. However, it is also possible to use a sensor specifically designed to measure atmospheric pressure or atmospheric pressure.

[0013] P 31363 / PCT

[0014] August 22, 2025 sphere pressure value to use an atmospheric pressure sensor that is separate from the flow pressure sensor.

[0015] It is also possible that the volumetric flow meter has an input or communication interface through which it can receive the atmospheric pressure value, for example from a control unit of the vacuuming device. For instance, the vacuuming device may have an atmospheric pressure sensor on board its control unit or on a circuit board of its control unit, so that it can transmit the atmospheric pressure value to the volumetric flow meter.

[0016] Furthermore, it is possible for the atmospheric pressure value to be received by the vacuum cleaner via a wireless interface, e.g., a radio interface and / or a Bluetooth interface, and / or a network interface, for example, an internet interface and / or a WLAN interface. The atmospheric pressure value could, for example, originate from a weather station located near the vacuum cleaner.

[0017] It is particularly preferred if the flow guide body, or at least a portion of the flow guide body accommodating the flow pressure sensor, projects freely into the flow channel. This portion of the flow guide body is preferably completely surrounded or able to be surrounded by the suction flow, except for a retaining section that serves to hold or support the flow guide body in the flow channel. The retaining section projects, for example, into the flow channel in the form of a projection, particularly a narrow projection, and holds or supports the portion of the flow guide body accommodating the flow pressure sensor. The retaining section can form an integral part of the flow guide body.

[0018] The flow guide is advantageously arranged in the flow channel of the suction device and / or advantageously projects into the flow channel. It is also possible for the flow channel to form a component of the flow guide. For example, the flow guide can be a ven-

[0019] P 31363 / PCT

[0020] August 22, 2025 turi body, i.e., that the suction flow passes by the flow pressure sensor according to the Venturi principle or acts on the flow pressure sensor.

[0021] Preferably, the flow guide is closed on one side facing the suction flow. Thus, for example, the flow pressure sensor is protected on its side facing the suction flow by the flow guide. The suction flow, which may be dust-laden or at least contain residual particles, is therefore prevented from reaching the flow pressure sensor by the flow guide.

[0022] Preferably, the flow guide body forms a housing or enclosure for the flow-pressure sensor. It is particularly advantageous if the flow guide body encloses the flow-pressure sensor, except for an inlet opening facing away from the suction flow or oriented against the flow direction of the suction flow.

[0023] It is particularly advantageous if the flow guide body encloses or covers the flow pressure sensor both on a side facing the suction flow and on one or more or all sides running essentially parallel to the suction flow.

[0024] The flow channel, or the section of the flow channel in which the flow pressure sensor is arranged, preferably has at least one flow obstruction downstream of the flow guide body or the flow pressure sensor to generate a pressure acting on the flow pressure sensor. The flow obstruction is, for example, a constriction or includes a constriction. Furthermore, the flow obstruction can also include one or more deflections of the suction flow, i.e., the suction flow encounters, for example, one or more flow contours oriented transversely to its flow direction upstream of the flow obstruction. The flow obstruction causes an increase in pressure in the region of the flow pressure sensor, particularly relative to atmospheric pressure.

[0025] P 31363 / PCT

[0026] August 22, 2025. Preferably, the at least one flow obstruction is arranged at a distance from the suction outlet and / or between the suction outlet and the suction unit. Thus, the flow obstruction is not the suction outlet itself, nor any grille, foam body, or the like that may be attached to it, which also reduces the flow velocity or the suction flow, but rather a flow obstruction located at a distance from it, in particular a deflection, constriction, or the like of the flow channel.

[0027] An advantageous measure provides that the flow-pressure sensor is advantageously arranged downstream of the suction unit. According to this measure, the flow-pressure sensor is arranged at or behind an outlet area of ​​the suction unit. Thus, the flow-pressure sensor is advantageously only exposed to those components of the suction flow that have been filtered by the filter arrangement of the suction unit.

[0028] Advantageously, the flow guide body has a wall on its side facing the suction flow that protects the flow pressure sensor.

[0029] Preferably, the flow pressure sensor is covered by at least one side wall extending in the direction of the suction flow, preferably several side walls extending in the direction of the suction flow, for example circumferential walls of a pipe body, of the flow guide body.

[0030] A longitudinal extension of the at least one side wall parallel to the flow direction of the suction flow is preferably at least equal in size, preferably at least 1.5 times as large, and even more preferably at least twice as large as the diameter of an inlet opening of the flow guide body, which is bounded in particular by the at least one side wall or the side walls of the flow guide body, through which pressure can act on the flow pressure sensor. Thus, the suction flow flowing along the at least one side wall or the side walls can pass over the longitudinal extension-

[0031] P 31363 / PCT

[0032] August 22, 2025 The flow along the side wall does not flow perpendicular to its main flow direction towards the flow-pressure sensor, but is directed away from the flow-pressure sensor or past the flow-pressure sensor by at least one side wall.

[0033] Advantageously, the flow guide body forms or has a protective housing, wherein the protective housing protects the flow-pressure sensor, except for an inlet opening for pressure acting on the flow-pressure sensor. The protective housing, for example, has an elongated shape extending along a longitudinal axis, wherein the longitudinal axis extends parallel to a principal directional component of the suction flow in the region of the flow guide body.

[0034] Furthermore, it is advantageous if the flow pressure sensor is arranged in a recess, in particular a tubular recess, of the flow guide body.

[0035] Advantageously, the flow guide body comprises at least one pipe body or pipe section, for example a Pitot tube, wherein the pipe body or pipe section has an inlet opening through which pressure generated by the suction flow can act on the flow pressure sensor, and has a closed end region opposite the inlet opening, e.g., a bottom, on which the flow pressure sensor is arranged. For example, the following is provided when the flow guide body is designed as a Pitot tube:

[0036] The flow guide advantageously comprises at least one pitot tube with an inlet opening for the suction flow and a closed end region opposite the inlet opening, on which the flow pressure sensor is arranged. The pitot tube is designed and configured to stagnate the suction flow.

[0037] P 31363 / PCT

[0038] August 22, 2025. The closed end region is, for example, a base on which the flow-pressure sensor is arranged. The base is preferably formed by a printed circuit board on which the flow-pressure sensor is arranged.

[0039] The design of the flow guide body with a pitot tube makes it possible to build up a dynamic pressure at the flow pressure sensor when the suction flow is present.

[0040] Pipe bodies, especially those used for Pitot tubes, are typically relatively thin, designed to obstruct airflow or suction as little as possible. However, in vacuum cleaner applications, it is advantageous for the pipe body, particularly the Pitot tube, and / or the entire volumetric flow measuring device to be as robust as possible.

[0041] An advantageous concept stipulates that the flow cross-section of the pipe section, particularly the Pitot tube, is at least twice the surface area of ​​the flow-pressure sensor. It is advantageous if the flow cross-section of the Pitot tube is at least 12 mm². 2 , preferably at least 15 mm 2 'even more preferably at least 20 mm 2 . Thus, for example, it is possible for the flow guide body to have a relatively massive shape, meaning it is as little susceptible as possible to mechanical damage.

[0042] The tube body is preferably at least 2 mm, preferably at least 3 mm, and even more preferably at least 4 mm or 5 mm long. The tube body is preferably at most 20 mm long, more preferably at most 15 mm, and even more preferably at most 10 mm long.

[0043] It can be designed so that the inlet opening in the flow channel faces the suction flow, allowing the suction flow to pass through the pipe section to the flow pressure sensor. This creates a Pitot tube.

[0044] One preferred variant provides that the inlet opening is turned away from the suction flow or is open against the flow direction of the suction flow, so that the suction flow is essentially directed towards the flow pressure sensor.

[0045] P 31363 / PCT

[0046] August 22, 2025. Therefore, the inlet opening in the flow channel is turned away from the suction flow, so that the pipe section directs the suction flow past the flow pressure sensor.

[0047] The flow guide advantageously has flow contours to guide the suction flow past the pipe section or the pitot tube. Thus, the suction flow, insofar as it does not enter the pipe section or the pitot tube and generate pressure there, can flow past the flow guide with as few disruptive contours as possible and / or in a flow-optimized manner.

[0048] For example, at least one oblique contour, a narrow and / or elliptical contour and / or a fin-like contour and / or a flattened and / or wing-like narrow side in the direction of flow from and / or in the direction of flow rear etc. is advantageous as a flow contour.

[0049] It is also advantageous if the flow guide has a fin-like or wing-like shape. For example, the flow guide projects into the flow channel of the suction device in a fin-like or wing-like manner.

[0050] It is advantageous for the flow guide body to have a streamlined shape. This streamlined shape need not be ideal. However, it is advantageous if the upstream side of the flow guide body, where the suction flow is directed, is wider than the downstream side of the flow guide body, where the suction flow flows away from the flow guide body.

[0051] It is advantageous if the upstream side of the flow guide, which is subject to the suction flow, has, for example, a curve or a wider side, while the downstream side, where the suction flow flows away from the flow guide, has a narrower side or a flow separation contour or edge. The flow guide is advantageously arranged in the flow channel in such an orientation and / or alignment.

[0052] P 31363 / PCT

[0053] August 22, 2025 It may be advantageous, in the sense of the most favorable flow guidance, that the flow guide body is designed to taper narrowly, pointedly, or flatly at its front side in the direction of flow and / or at its rear side in the direction of flow towards its respective free end area.

[0054] Regarding installation, it can be advantageous for the flow guide to have a projection on its leading edge (in the direction of flow) for positioning in the flow channel and / or an L-shaped form. This makes it easier to insert the flow guide into the suction device's flow channel, for example, with a pivoting or hooking motion.

[0055] In the direction of flow, rearward of the suction flow, it is advantageous if the flow guide body has at least one flow separation contour, for example, a flow separation edge. This allows the flow guide body to be relatively short on its rearward side (relative to the direction of the suction flow). This is also advantageous for the most convenient mounting on the suction device.

[0056] Furthermore, an advantageous embodiment of the invention provides that at least one of the sensors of the volume flow measuring device, for example the flow pressure sensor and / or the atmospheric pressure sensor and / or a temperature sensor to be explained later, is arranged on a sensor carrier which can be detachably connected to the suction cup housing and / or inserted into the suction cup housing.

[0057] The sensor carrier can be attached to or removed from the vacuum cleaner housing as needed.

[0058] It is preferred that the sensor carrier has at least one flange, in particular a mounting flange, for supporting a wall of the suction housing. The wall, for example, defines a flow channel for the suction flow or is a channel wall. Furthermore, it is advantageous if the sensor carrier

[0059] P 31363 / PCT

[0060] The sensor carrier, dated August 22, 2025, features opposing flanges that define a receiving groove. The wall of the suction device can engage in this receiving groove. For example, when mounted on the wall, the sensor carrier clamps onto this wall with its two opposing flanges. The sensor carrier can be, in effect, attached to the wall and / or the suction device using one or both flanges.

[0061] Preferably, the sensor carrier incorporates or forms the flow guide. However, it is also possible for the flow guide to be a separate element from the sensor carrier. For example, the flow guide can be attached to the sensor carrier.

[0062] It is preferred that the sensor carrier be made at least partially of an elastic material, such as rubber, a plastic with elastic properties, a rubber-like material, or the like. This elastic material can, for example, facilitate its insertion into the wall of the suction device. For instance, one or both flanges are made of the elastic material and yield elastically when inserted into, for example, a mounting opening in the wall of the suction device housing.

[0063] Furthermore, an advantageous concept provides that the sensor carrier has a circuit board on which at least one of the sensors of the volume flow measuring device, for example the flow-pressure sensor, is arranged.

[0064] The printed circuit board (PCB) is advantageously embedded wholly or partially in the elastic material or encased by the elastic material. Thus, the elastic material forms, for example, a protective body to cover and / or protect the PCB. However, it is possible that parts of the PCB protrude beyond the protective body or the elastic material, for example, those areas of the PCB where a sensor is located, such as a temperature sensor, a flow-pressure sensor, or the like.

[0065] It should be mentioned here that the elastic material is advantageous for forming the flow guide body. However, it is also possible that parts of the

[0066] P 31363 / PCT

[0067] August 22, 2025. Sensor carriers located outside the flow channel are coated with a rubber-like or elastic material. In any case, this provides a certain degree of protection.

[0068] Preferably, the volumetric flow meter has at least one temperature sensor. Using the temperature sensor, the volumetric flow meter can, for example, detect an increased temperature of the suction flow. If, for instance, the suction unit is overloaded, the suction flow becomes hotter, which the volumetric flow meter can detect using the at least one temperature sensor.

[0069] The temperature sensor is preferably arranged on the sensor carrier. In particular, the temperature sensor is arranged on the aforementioned circuit board.

[0070] It is advantageous if the temperature sensor is located outside of a Pitot tube and / or a detection area of ​​the flow-pressure sensor that is subjected to dynamic pressure by the volume flow.

[0071] It should be noted that the atmospheric pressure sensor is advantageously located outside the flow channel. For example, the atmospheric pressure sensor is located on a section of the sensor carrier that projects in front of and / or out of the flow channel.

[0072] The flow pressure sensor, and optionally the atmospheric pressure sensor if present, is preferably protected against water and / or other environmental influences and / or has a pressure-measuring membrane coated with a protective layer, in particular gel, which serves to protect against water or other environmental influences. Thus, the flow pressure sensor or atmospheric pressure sensor can operate reliably even if particles, moisture, or the like are present in the suction flow and act upon the pressure sensor.

[0073] It is preferred that the flow channel has no constriction in the area of ​​the volume flow measuring device and / or in the area of ​​the flow pressure sensor.

[0074] P 31363 / PCT

[0075] August 22, 2025, and / or has a constant cross-section. For example, no Venturi nozzle or similar flow guide is provided.

[0076] Furthermore, it is advantageous if the flow pressure sensor or a part of the volume flow measuring device that projects into the flow channel only covers a maximum of 30%, in particular a maximum of 20%, or even more preferably 10% of the flow cross-section of the area into which the volume flow measuring device engages.

[0077] The flow channel advantageously has a straight shape in the area of ​​the flow-pressure sensor. This allows, for example, a particularly constant and uniform flow of the suction stream.

[0078] It is further advantageous if the flow channel in the area of ​​the flow-pressure sensor is designed as a channel for guiding pipe and / or channel flow. This measure also serves to ensure that the suction flow is as constant or uniform as possible.

[0079] An invention that is independent in itself in connection with the preamble features of claim 1 or a suction device of the type mentioned at the outset, but also an advantageous embodiment of the invention, provides that the volume flow measuring device is designed to determine an atmospheric pressure value, in particular on the basis of an atmospheric pressure sensor, wherein the atmospheric pressure value represents an atmospheric pressure in the vicinity of the suction device, and that the volume flow measuring device is designed to determine a volume flow value representing a volume flow of the suction flow on the basis of a difference between the flow pressure value and the atmospheric pressure value.

[0080] A corresponding procedure can be defined as follows:

[0081] Method for measuring the volume flow rate of a vacuum cleaner with a vacuum cleaner housing in which a dust collection chamber for collecting dust and a suction unit for generating a suction flow are arranged, wherein the vacuum cleaner has a suction inlet through which the suction flow enters the dust-

[0082] P 31363 / PCT

[0083] 22 August 2025 collection chamber, and has a suction flow outlet through which the suction flow can flow out of the vacuum cleaner housing, wherein the suction unit is arranged between the suction inlet and the suction flow outlet, and wherein at least one filter element for removing dust from the suction flow is arranged between the suction unit and the dust collection chamber, and wherein the suction unit is arranged in a flow channel between the at least one filter and the suction flow outlet, wherein the following is provided:

[0084] - Determination of a flow pressure value using a flow pressure sensor of the volume flow measuring device, wherein the flow pressure sensor is flow-connected to the flow channel in such a way that, when the suction unit is in operation, the suction flow acts on the flow pressure sensor to generate a flow pressure,

[0085] - Determination of an atmospheric pressure value using the volume flow measuring device, in particular using an atmospheric pressure sensor, wherein the atmospheric pressure value represents an atmospheric pressure in the vicinity of the suction device, and

[0086] - Determination of a volume flow value representing a volume flow of the suction flow based on a difference between the flow pressure value and the atmospheric pressure value by the volume flow measuring device.

[0087] Advantageously, a program module is provided for the execution of the procedure, which contains program code executable by a processor and / or a computing unit, whereby the procedure is executed in whole or in part when the program code is executed.

[0088] It is advantageous if the volume flow measuring device has all the means necessary for carrying out the procedure, for example a computing unit and / or a processor, memory and the like.

[0089] However, it is also possible that the volumetric flow measurement device is at least partially implemented by a control unit of the suction device, which is intended to control the suction unit, for example, to switch it on or off or adjust its power. The control unit-

[0090] P 31363 / PCT

[0091] August 22, 2025 The suction device preferably has a processor that can process program code, during the execution of which the method according to the invention is carried out.

[0092] An advantageous concept involves the volumetric flow measurement device, particularly the flow-pressure sensor, being designed and configured to determine the atmospheric pressure before the vacuum unit is switched on. This method thus provides that the atmospheric pressure is first detected and determined by the volumetric flow measurement device, for example, via a sensor input, the flow-pressure sensor, or the internet, before the vacuum unit is switched on. It is assumed that the atmospheric pressure does not change, or changes only negligibly, during operation of the vacuum unit; that is, the reference value for determining the volumetric flow rate based on the flow-pressure remains constant or essentially constant.

[0093] The following measures help to ensure that the atmospheric pressure value is recorded in the absence of suction flow and / or that the suction flow does not interfere with or influence the recording of the atmospheric pressure value.

[0094] Advantageously, the volume flow measuring device is designed to detect a switch-on signal for the suction unit, and the volume flow measuring device is designed to detect the atmospheric pressure value as a function of the switch-on signal. In particular, a control device of the suction unit is designed to switch on the suction unit only when the volume flow measuring device has detected the atmospheric pressure value.

[0095] Furthermore, it is advantageously provided that the volume flow measuring device is designed to detect a switch-off signal for the suction unit and / or a suction unit switch-off information indicating that the suction unit is switched off, and to measure the atmospheric pressure value according to a predetermined or user-defined time.

[0096] P 31363 / PCT

[0097] The atmospheric pressure value is recorded after the switch-off signal or the suction unit switch-off information is received on August 22, 2025, during an adjustable delay period.

[0098] It may be advantageously provided that the volume flow measuring device determines the atmospheric pressure value using the flow pressure sensor, i.e., that no additional atmospheric pressure sensor is necessary and / or no sensor input is available or required to receive the atmospheric pressure value from another source, for example, from the control of the suction device, from the internet, or the like.

[0099] Therefore, it is advantageous if the flow pressure sensor is the only pressure sensor provided or available for determining the volumetric flow rate in the volumetric flow measurement device. Furthermore, it is advantageous if no additional sensor input for atmospheric pressure is required. The design is simple and cost-effective to implement.

[0100] The flow pressure sensor and / or atmospheric pressure sensor advantageously uses so-called barometric pressure sensors and / or absolute pressure sensors and / or no differential pressure sensors. For example, one or both of the aforementioned pressure sensors are suitable and intended for measuring barometric pressure in weather stations, drones, fitness watches, or similar devices. For example, pressure sensors with the type designation ST LPS27HHW or Infineon DPS368 can be used.

[0101] As already mentioned, it is advantageous if the suction device has a separate atmospheric pressure sensor for determining the atmospheric pressure value.

[0102] It is advantageous if the suction device and / or the volume flow measuring device is designed and / or intended to determine the volume flow value during the operation of the suction unit.

[0103] For example, the atmospheric pressure can be continuously monitored during vacuuming operation, i.e., during suction flow, via a sensor input, a communication interface to a control unit of the vacuuming device, or the like.

[0104] P 31363 / PCT

[0105] The atmospheric pressure value will be determined on August 22, 2025. For this purpose, the aforementioned separate atmospheric pressure sensor and / or a sensor input of the volumetric flow meter, designed and intended to receive the atmospheric pressure value, are suitable. The sensor input can, for example, be a bus interface or include electrical connections for a sensor separate from the volumetric flow meter.

[0106] The suction device and / or the volume flow measuring device can continuously determine the volume flow value during operation of the suction unit by measuring the difference between, for example, the flow pressure values ​​provided by the flow pressure sensor or a sensor input and the atmospheric pressure values ​​provided by the atmospheric pressure sensor and / or a sensor input. "Continuously" in this context also means that the suction device or the volume flow measuring device determines the volume flow regularly, e.g., at regular intervals and / or at short intervals, for example, at intervals of no more than 1 minute, preferably no more than 30 seconds, even more preferably no more than 15 seconds, and even more preferably no more than 5 seconds.

[0107] The vacuum cleaner's volume flow meter can, for example, implement a so-called "M-function," meaning safe operation of the vacuum cleaner for dust class M (medium-hazardous dusts). Medium-hazardous dusts include, for example, wood dust, paint particles, and various metal dusts. If the required volume flow for dust class M is no longer guaranteed, the vacuum cleaner issues a warning, such as a visual and / or audible warning. The vacuum cleaner then provides and / or ensures the M-function.

[0108] The suction device, for example the volume flow measuring device, is preferably designed to issue at least one warning depending on the volume flow, in particular depending on a volume flow dependent on a predetermined dust class, and has output means for issuing

[0109] P 31363 / PCT

[0110] August 22, 2025, an optical and / or acoustic warning will be issued if a predetermined or adjustable volume flow value is exceeded.

[0111] A modular concept is advantageous in which the volumetric flow meter, or a sensor carrier of the volumetric flow meter (which includes at least the flow-pressure sensor), is designed as a module that is either detachably mounted on the suction device and / or can be retrofitted. Thus, if, for example, a warning function or M-function is required, the volumetric flow meter is mounted on the suction device. Alternatively, a temperature-only measuring device can be installed on the suction device instead of the volumetric flow meter.

[0112] The module or sensor carrier preferably has a communication interface for communication with a control unit of the vacuuming device. This allows, for example, sensor data from the module or sensor carrier to be transmitted to the control unit of the vacuuming device for further processing.

[0113] For example, the suction unit is part of a system that includes the suction unit itself, a volumetric flow meter, and a temperature meter, with the temperature meter being mountable on the suction unit in place of the volumetric flow meter. Both modules are optionally usable and / or mountable, e.g., selectable during initial assembly and / or interchangeable as needed, e.g., for retrofitting with a different module. This approach enables, for example, simplified manufacturing or a common parts principle.

[0114] Advantageously, the suction unit is arranged in a suction unit receiving chamber of the vacuum cleaner housing and blows the suction flow into a discharge duct which is arranged on the suction unit receiving chamber of the vacuum cleaner housing, wherein the discharge duct extends around the suction unit receiving chamber of the vacuum cleaner housing from an initial region of the discharge duct to a channel provided for the discharge of the suction flow.

[0115] P 31363 / PCT

[0116] 22 August 2025 outlet of the blow-off channel extends in a ring shape around the suction unit intake chamber, and wherein a flow cross-section of the blow-off channel increases continuously from its initial area to the channel outlet of the blow-off channel.

[0117] The basic principle is that the discharge duct should exhibit a flow resistance that is as constant as possible, or at least does not increase significantly, from its inlet to the outlet. It is also possible for the discharge duct to have a decreasing flow resistance from its inlet to the outlet. Thus, from the inlet to the outlet, an ever-increasing volume of suction flow generated by the suction unit can flow through the discharge duct with minimal flow resistance.

[0118] It is possible that the discharge duct has the same or non-increasing flow cross-section at one or more sections of the discharge duct, particularly in the area of ​​the duct outlet or in front of the duct outlet.

[0119] The suction unit can be a suction turbine alone or a combination of a suction turbine and a suction motor. The discharge duct extends, for example, around the outer circumference of the suction turbine, on which discharge openings of the suction turbine are arranged for expelling the suction flow.

[0120] The initial section of the discharge duct is advantageously located directly next to the duct outlet. Thus, the discharge duct extends virtually completely around the suction unit.

[0121] The initial section and the duct outlet are separated, for example, by a tongue or a tongue-like wall projecting towards the outer circumference of the suction unit. Thus, the tongue or the projecting wall creates a narrowing of the discharge duct at the initial section. At the wall or at the

[0122] P 31363 / PCT

[0123] August 22, 2025 The tongue may be provided with an elastic seal that seals against the outer circumference of the suction turbine or suction unit.

[0124] Advantageously, the suction flow exits the discharge duct tangentially with respect to an outer circumference of the suction unit and / or the suction unit intake chamber.

[0125] The discharge duct, for example, extends in a spiral shape around the suction unit intake chamber.

[0126] Advantageously, the discharge duct extends completely, at least 90% or at least 80%, around the suction unit intake space.

[0127] The suction unit advantageously has outlet openings located opposite a circumferential wall that defines the discharge channel. Thus, the suction flow exits the suction unit through the outlet openings in the direction of the circumferential wall.

[0128] The outlet openings are advantageously aligned tangentially to the direction of the suction flow, i.e., they are advantageously oriented to allow the suction flow to be expelled tangentially in the direction of the suction flow. Thus, the suction flow approaches the circumferential wall virtually unimpeded and in the circumferential direction.

[0129] The circumferential wall advantageously has a distance from the outer circumference of the suction unit that is smaller in the initial region of the discharge duct than in the region of the duct outlet. The circumferential wall can have an arc-shaped and / or circular segment-like cross-section, i.e., perpendicular to the direction of the suction flow, particularly in a region adjacent to or above the discharge openings of the suction unit. Opposite the discharge openings, the circumferential wall preferably has a substantially straight cross-sectional contour.

[0130] P 31363 / PCT

[0131] August 22, 2025. It is advantageous if the outlet of the discharge duct opens into a section of the flow channel or is connected to a flow section of the flow channel that is designed and / or intended to form a pipe flow and / or a channel flow of the suction stream. The flow channel can also have a substantially constant flow cross-section over a longitudinal length that is at least equal to its transverse width. In any case, it is advantageous if there is as little flow resistance as possible in the area of ​​the duct outlet.

[0132] It is advantageous to arrange a volume flow measuring device in the flow section of the flow channel.

[0133] The vacuum cleaner is preferably a workshop vacuum or construction site vacuum.

[0134] The suction device is preferably designed for operation together with a machine tool, in particular a hand-held machine tool, for example for the extraction of dusts that arise during the operation of the hand-held machine tool.

[0135] The invention relates to a vacuum device with a vacuum housing in which a dust collection chamber for collecting dust and a suction unit for generating a suction flow are arranged, wherein the vacuum device has a suction inlet through which the suction flow can flow into the dust collection chamber and a suction flow outlet through which the suction flow can flow out of the vacuum housing, wherein the suction unit is arranged between the suction inlet and the suction flow outlet and at least one filter element for removing dust from the suction flow is arranged between the suction unit and the dust collection chamber, and wherein the suction unit is arranged in a flow channel between the at least one filter and the suction flow outlet.The suction device has a volume flow measuring device for determining a volume flow value of the suction flow, which has a flow pressure sensor for determining a flow pressure value, which is flow-connected to the flow channel in such a way that when in operation-.

[0136] P 31363 / PCT

[0137] August 22, 2025. The suction flow of the suction unit acts on the flow-pressure sensor to generate a flow pressure. The determination of an atmospheric pressure value is provided, where the atmospheric pressure value represents the atmospheric pressure in the vicinity of the suction unit. The volumetric flow measuring device is designed to determine a volumetric flow value representing the volumetric flow of the suction flow based on the difference between the flow pressure value and the atmospheric pressure value.

[0138] The following are examples of implementation explained with reference to the drawing. The drawing shows:

[0139] Figure 1 shows a perspective oblique view of a system comprising a suction device and a hand-held power tool.

[0140] Figure 2 shows a partially cut section of the suction device according to Figure 1, approximately along a section line AA in Figure 1.

[0141] Figure 3 shows a cross-section through a housing upper part of the suction device housing according to Figure 1, approximately along a section line BB in Figure 1 ,

[0142] Figure 4 shows a partial sectional view through the suction housing of the suction device according to the preceding figures, approximately along a section line CC in Figure 3.

[0143] Figure 5 shows a perspective oblique view of a volume flow measuring device of the suction device according to the preceding figures,

[0144] Figure 6 shows a frontal view of the volume flow measuring device according to Figure

[0145] 5,

[0146] Figure 7 shows a section through the volume flow measuring device according to Figure

[0147] 6, approximately along a section line DD,

[0148] P 31363 / PCT

[0149] August 22, 2025 Figure 8 a flowchart of a program module for carrying out the method according to the invention,

[0150] Figure 9 shows a diagram illustrating the relationship between pressure values ​​and a volume flow rate value determined by the volume flow measuring device.

[0151] Figure 10 shows the view corresponding to Figure 3, but with an alternative arrangement of the volume flow measuring device.

[0152] Figure 11 shows the volume flow measuring device according to the alternative arrangement from Figure 10 in a representation corresponding to Figure 7.

[0153] A vacuum unit 10 has a vacuum housing 11. The vacuum unit 10 is, for example, a vacuum cleaner for a construction site, for use in a workshop, or the like. The vacuum unit 10 has rollers 17 on its underside for rolling on a surface. The vacuum unit 10 is preferably used for extracting dust generated during the operation of hand-held power tools, in particular grinders, saws, or the like.

[0154] The suction cup housing 11 has a lower housing part 12 and an upper housing part.

[0155] 13, that the lower housing part 12 covers. In the vacuum cleaner housing 11, in particular the lower housing part 12, a dust collection chamber 14 is arranged for collecting dust. Dust can be collected directly in the dust collection chamber 14 or in a filter bag that is placed in the dust collection chamber.

[0156] 14 can be arranged optionally.

[0157] A suction flow S can be drawn into the dust collection chamber 14 via a suction inlet 15. The suction inlet 15 is, for example, located on the lower housing part 12 and is connected to the dust collection chamber 14 by airflow. A suction hose 16 can optionally be connected to the suction inlet 15.

[0158] P 31363 / PCT

[0159] August 22, 2025 The suction hose 16 is also advantageously connected to a hand-held power tool H, for example a sawing machine, in order to extract dust, particles or the like that accumulating during its operation by means of the suction device 10.

[0160] The vacuum cleaner housing 11 is further equipped with operating elements 18, such as buttons, in particular membrane keys, a socket for plugging in a hand-held power tool, or the like. The vacuum cleaner 10 can be switched on and off using the operating elements 18. Advantageously, the power output of the vacuum cleaner 10 can also be adjusted using the operating elements 18. Furthermore, it is advantageous if the vacuum cleaner 10 has a wireless receiving interface for wireless control by a hand-held power tool.

[0161] The upper part of the housing 13 has a shelf 19 for storing items such as the suction hose 16, a power cord for supplying power to the vacuum cleaner 10, or the like. Advantageously, a handle for gripping the vacuum cleaner 10 is located in front of the shelf 19.

[0162] A suction unit 20 is provided to generate the suction flow S, which is arranged in the suction housing 11, in particular in the upper part of the housing 13. The suction unit 20 comprises a suction motor 21, in particular an electric suction motor 21, and a suction turbine 22 for generating the suction flow S, which is driven by the suction motor 21.

[0163] The suction unit 20 is advantageously a module.

[0164] The suction unit 20, for example, forms a modular unit consisting of a suction motor 21 and a suction turbine 22, which can be easily replaced. The suction turbine 22 includes, for example, a turbine wheel or fan wheel 22A.

[0165] The suction unit 20 is housed in a suction unit receiving chamber 23 of the suction housing 11, which is closed by a cover 25.

[0166] P 31363 / PCT

[0167] August 22, 2025. The cover 25 can be a separate cover specifically designed to close the suction unit intake chamber 23. However, it is also possible that a wall 26 of the suction unit housing 11, for example, the upper housing part 13, provides the cover 25. For example, the wall 26 can be used to close the upper housing part 13.

[0168] The suction unit receiving chamber 23 includes a suction unit receptacle 24 into which the suction unit 20 engages. Advantageously, the suction motor 21 is arranged in the receptacle 24, while the suction turbine 22 projects in front of the receptacle 24.

[0169] The suction unit 20 is sealed by means of seals 27, 28 and 29, for example such that the seal 27 is arranged on a base of the suction unit receptacle 24. The seal 28 seals, for example, the receptacle 24 against the suction turbine 22. For example, the seal 28 is arranged on an outer circumference of an inlet opening of the receptacle 24. In particular, the seal 28 is arranged between the suction motor 21 and the suction turbine 22, so that the suction motor 21 is flow-tightly enclosed in the receptacle 24 and the suction flow S generated by the suction turbine 22 does not flow into the receptacle 24.

[0170] As explained, a filter bag can be used in the dust collection chamber 14, which filters out dust ST from the suction stream S, so that the dust ST remains in the dust collection chamber 14.

[0171] Alternatively or in addition to the filter bag, at least one further filter element 30 is provided in the vacuum unit 10, e.g., a main filter 31, which is arranged between the dust collection chamber 14 and the suction unit 20, which serves to generate the suction flow S. The main filter 31 is, for example, designed as a pleated filter and can be easily replaced if necessary. The main filter 31 can filter dust ST out of the suction flow S.

[0172] An additional, optional filter, namely an auxiliary filter 32, is arranged between the main filter 31 and the suction unit 20. The filter 32 is, for example,

[0173] P 31363 / PCT

[0174] August 22, 2025, a HEPA filter (HEPA = High Efficient Particulate Air). Preferably, the additional filter 32 is housed in a filter drawer.

[0175] For cleaning the main filter 31, especially when no filter bag is used, a cleaning device 40 is provided, which includes, for example, a schematically shown closing valve 41 and an external air valve 42.

[0176] The external air valve 42 communicates via an external air channel 44 with an external air inlet 43 which is open to the environment of the suction device and which is opened by the external air valve 42 during a cleaning process, so that an external air flow F flows through the main filter 31 against the flow direction of the suction flow S and the main filter 31 is thereby cleaned.

[0177] The closing valve 41 is arranged in a flow channel 45 for the suction flow S between the main filter 31 and the suction unit 20, preferably between the main filter 31 and the auxiliary filter 32. During cleaning, the cleaning device 40 closes the closing valve 41, thus closing the flow channel 45, and opens the external air valve 42, creating a negative pressure in the area of ​​the dust collection chamber 14. This causes external air to flow through the main filter 31 via the external air inlet 43, against the direction of the suction flow S, thus cleaning the main filter 31 in the direction of the dust collection chamber 14.

[0178] The flow channel 45 has several sections.

[0179] For example, a channel section 46 extends from the side of the main filter 31 facing away from the dust collection chamber 14 to the outside air valve 42 and the closing valve 41 .

[0180] A schematically depicted channel section 47 establishes a flow connection between the closing valve 41 and the auxiliary filter 32. A channel section 48 leads from the auxiliary filter 32 to the suction unit 20. For example, the channel section 48 includes passage openings 48A for the suction flow S, which are located on the cover.

[0181] P 31363 / PCT

[0182] 22 August 2025 25 is arranged so that the suction flow S can be drawn in by the suction turbine 22.

[0183] The suction turbine 22 blows the suction flow S into a discharge duct 50. The discharge duct 50 extends in a ring shape around the outer circumference of the suction turbine 22.

[0184] The discharge duct 50 is a ring duct or an annular duct.

[0185] The spiral shape of the 50 mm discharge duct is advantageous.

[0186] The discharge channel 50 has an initial area 52 which essentially acts as a separator with respect to flows, for example separating a part of the suction flow S flowing into the discharge channel 50 from the suction turbine 22 and a part of the suction flow S flowing through the channel outlet 54 from each other in terms of flow technology.

[0187] From the initial section 52, the discharge duct 50 extends over a circumferential section 53 around the suction turbine 22 and opens into a duct outlet 54. The duct outlet 54 is located next to the initial section 52, so that, as a result, the air discharged by the suction turbine 22, i.e., the suction flow S, flows from the initial section 52 over the circumferential section 53 to the duct outlet 54.

[0188] The discharge duct 50 has a flow cross-section SQ that increases from the initial section 52 towards the duct outlet 54. For example, the discharge duct 50 has a flow cross-section SQ1 at the initial section 52 that is smaller than a flow cross-section SQ2 at the duct outlet 54. It is advantageous if the flow cross-section of the discharge duct 50 increases continuously from the initial section 52 to the duct outlet 54 and / or does not decrease.

[0189] It is advantageous if the annular channel or blow-out channel 50 has a spiral shape.

[0190] P 31363 / PCT

[0191] August 22, 2025 A side wall or circumferential wall 55 of the discharge duct 50 opposite the outer circumference 22B of the suction turbine 22 is located in the initial region 52 at a small distance D52 and thus close to the outer circumference of the suction turbine 22, so that at the initial region 52 little or almost no air can flow between the suction turbine 22 and the circumferential wall 55.

[0192] In the area of ​​the channel outlet 54, however, the discharge channel 50 has a larger cross-section. For example, the circumferential wall 55 at the channel outlet 54 has a greater distance D54 from the outer circumference 22B of the suction turbine 22 compared to the distance D52.

[0193] Advantageously, the circumferential wall 55 is spiral-shaped, i.e., in the initial area 52 it is arranged closer to the suction turbine 22 than at the channel outlet 54.

[0194] The height of the discharge duct 50, defined by its upper and lower side walls, is, for example, the same at the starting region 52 and at the duct outlet 54. Thus, the course of the circumferential wall 55 in relation to the outer circumference 22B of the suction turbine 22, from the starting region 52 towards the duct outlet 54, results in an increase in the flow cross-section SQ from flow cross-section SQ1 to flow cross-section SQ2.

[0195] However, it is also possible that only the upper and lower side walls of the discharge duct 50 from the initial section 52 to the duct outlet 54 have larger distances from each other in order to increase the flow cross-section SQ. Furthermore, a combination is also possible in which both the height of the discharge duct and its transverse width increase perpendicular to the height from the initial section to the duct outlet.

[0196] Changing the distance between the upper and lower side walls to increase the flow cross-section from the initial area to the channel outlet is not only possible in the specific embodiment shown in the drawing, but can be implemented in any suction device with a discharge channel whose flow cross-section increases from the initial area to the channel outlet.

[0197] P 31363 / PCT

[0198] August 22, 2025 Figure 4 schematically shows the flow cross-section SQ.

[0199] The relatively small, but existing, distance D52 is sufficient for an essentially flow-separated situation, in which at most small portions of the suction flow S flow directly from the initial region 52 towards the channel outlet 54 without passing through the discharge channel 50. For example, the flow direction of the suction flow S exiting the suction turbine 22 and / or the pressure situation is such that the suction flow S flows from the initial region 52 through the discharge channel 50 to the channel outlet 54.

[0200] Without further ado, the initial area 52 could be completely sealed off from the channel outlet 54, for example by means of an elastic seal not shown, etc.

[0201] Furthermore, it is advantageous if the outlet openings 22C of the suction turbine 22, which are arranged, for example, on its outer circumference 22B, direct the suction flow S and / or blow it into the discharge duct 50 in a predetermined direction. For example, walls 22D are arranged at the outlet openings 22C, or the outlet openings 22C are partially bounded by walls 22D that direct the suction flow S.

[0202] The suction flow S flows out of the outlet openings 22C, which are opposite the circumferential wall 55, in a flow direction SR. However, the flow direction SR is chosen such that the suction flow S flows tangentially out of the outlet openings 22C, i.e., in a direction such that the suction flow SR flows along the circumferential wall 55 and does not impinge on the circumferential wall 55 at an angle.

[0203] This measure also ensures that the suction flow S from the initial section 52 flows through the discharge channel 50 or annular channel before exiting the channel outlet 54. A direct transition of the suction flow S from the initial section 52 into, for example, the flow section 56, without the suction flow S passing through the discharge channel 50, is thereby prevented, or at least such an effect is reduced.

[0204] P 31363 / PCT

[0205] August 22, 2025. The channel outlet 54 opens into a straight flow section 56 of the flow channel 45. In the straight flow section 56, the suction flow S flows in a substantially constant flow cross-section or even a slightly increasing flow cross-section of the flow channel 45, so that the suction flow S in the flow section 56 exhibits a straight flow or pipe flow or channel flow.

[0206] The flow section 56 is followed by a curved section 60 of the flow channel 45, from which the flow channel 45 continues towards a side facing away from the lower part of the housing 12 into a channel section 61. From channel section 61, a channel section 62 of the flow channel 45 leads to the outside of the suction housing 11, where the suction flow S exits the suction housing 11 via a suction flow outlet 63.

[0207] Figure 4 shows that the circumferential wall or side wall 55 need not be straight over its entire height, which extends parallel to a rotational axis DA of the suction turbine 22, nor need it be the same distance from the outer circumference 22B of the suction turbine 22. The side wall 55 can, for example, have a curved profile, particularly next to and / or above the discharge openings 22C. The discharge duct 50 can therefore also have, for example, a circular segment-shaped cross-section.

[0208] The outlet filter 33 is preferably arranged at or in front of the suction flow outlet 63.

[0209] As already mentioned, the suction unit 10 is designed for professional use. It is therefore essential that the suction flow rate S always maintains a predetermined level, ensuring that a minimum amount of dust from a hand-held power tool H or similar device is always extracted. A volumetric flow meter 100 is provided to guarantee a sufficient volumetric flow rate S.

[0210] The volume flow measuring device 100 has a flow pressure sensor 101 and optionally an atmospheric pressure sensor 102. Furthermore, the Vo-

[0211] P 31363 / PCT

[0212] August 22, 2025, lumen current measuring device advantageously also includes a temperature sensor 103.

[0213] The volume flow measuring device 100 is modular, i.e. it can optionally be arranged on the suction device 10 or omitted.

[0214] For example, the volume flow measuring device is arranged on a cover wall 64 of the flow section 56 of the flow channel 45 and projects into the flow section 56 and thus into the flow channel 45.

[0215] For example, an opening 65 is provided on the cover wall 64 through which a sensor carrier 110 can be inserted, so that the sensor carrier 110 partially protrudes into the flow channel 45 and in particular the flow section 56.

[0216] The sensor carrier 110 has a support body 111 for a circuit board or printed circuit board 112.

[0217] The circuit board 112 is advantageously arranged partially or substantially outside the flow channel 45.

[0218] The circuit board 112 advantageously carries all electrical components of the volume flow measuring device 100.

[0219] A measuring projection 120 is located in front of a support section 116 of the support body 111, on which the flow pressure sensor 101 and optionally the temperature sensor 103 are arranged.

[0220] The measuring protrusion 120 extends into the flow section 56 and thus into the flow channel 45.

[0221] The support section 116 is located outside the flow channel 45 or the flow section 56.

[0222] P 31363 / PCT

[0223] August 22, 2025. Flanges 113 and 114 are provided opposite each other between the support body 111 and the measuring projection 120. The flanges 113 and 114 are located between the support section 116 and the measuring projection 120.

[0224] The flanges 113 and 114 are annular flanges, between which a receiving groove 115 is formed. A section of the cover wall 64, which defines the opening 65, can engage in the receiving groove 115. Thus, the sensor carrier 110 can be, so to speak, attached to the cover wall 64 by means of the flanges 113 and 114.

[0225] The support section 116 is, for example, arranged on a side of the sensor carrier 110 opposite the measuring projection 120.

[0226] The flange 113 facing the support section 116 has a larger support area or surface area or a larger circumferential radius than the flange 114 facing the measuring projection.

[0227] Flange 113 and / or flange 114 may have a recess on its outer circumference.

[0228] It is advantageous that the sensor carrier 110 consists of an elastic material at least in the area of ​​the flanges 113, 114, in particular the flanges 113, 114 are elastically flexible so that they can be brought into engagement with the cover wall 64 in the area of ​​the opening 65.

[0229] Advantageously, the atmospheric pressure sensor 102 is arranged on a section of the circuit board 112 located in the area of ​​the support section 116. However, the temperature sensor 103 and the flow pressure sensor 101 are designed for arrangement in the flow channel 45 and are, for example, located on the measuring projection 120.

[0230] The circuit board 112 extends from the support section 116 into the measuring projection 120, which enables an optimal wiring concept.

[0231] P 31363 / PCT

[0232] August 22, 2025 The measuring protrusion 120 comprises a flow guide body 121, which is arranged in the suction flow channel 45 and its flow section 56.

[0233] The flow guide body 121 comprises a pipe section 122 having an inlet opening 123 through which part of the suction flow S can enter the pipe section 122. Preferably, the inlet opening 123 of the flow guide body 121 is oriented opposite to the flow direction of the suction flow S.

[0234] Components of the suction flow S that do not enter the pipe section 122 can optimally flow past the measuring projection 120 and, in particular, the flow guide body 121. Advantageously, the pipe section 112 is wedge-shaped on the outside and / or has inclined contours 124.

[0235] The oblique contours 124, for example, form flow contours 124A.

[0236] The flow contours 124A are preferably elliptical.

[0237] The flow contours 124A can, for example, be designed or shaped in the manner of subsections of an ellipse.

[0238] With regard to the flow direction SR at the rear, the measuring projection 120 advantageously has a flow separation contour 124B.

[0239] The pipe section 122 comprises a pipe body, e.g., a pitot tube 125, which is open at the inlet opening 123 and closed on one side opposite the inlet opening 123, e.g., a closed end section or bottom 126. The suction flow S backs up at the closed end section or bottom 126.

[0240] The flow pressure sensor 101 is arranged at the closed end area or bottom 126, which can measure a dynamic pressure in the pitot tube 125.

[0241] P 31363 / PCT

[0242] August 22, 2025. A membrane of the flow-pressure sensor 101, or the flow-pressure sensor 101 as a whole (not shown in detail in the drawing), is advantageously protected against environmental influences by a protective layer 105, for example, a gel. Thus, if, for example, some moisture, dust, particles, or the like are still present in the suction flow S, the protective layer 105 protects the flow-pressure sensor 101. It is possible that the closed end region of the Pitot tube 125, i.e., the bottom 126, is completely covered by a protective layer behind which the flow-pressure sensor 101 is located.

[0243] The temperature sensor 103 is designed and intended for measuring the temperature of the suction flow S. The temperature sensor 103 provides, for example, temperature values ​​TD.

[0244] In front of the pipe section 122 of the measuring projection 120, there is a support projection 127 on which the temperature sensor 123 is arranged.

[0245] The circuit board 112 extends to the support projection 127, so that the temperature sensor 103 can also be arranged on the circuit board 112.

[0246] The temperature sensor 103 faces the suction flow S, is therefore directly exposed to the suction flow S and / or is subjected to the suction flow S.

[0247] Advantageously, the flow pressure sensor 101 and the temperature sensor 103 are arranged on the same side of the circuit board 112.

[0248] Sensor data 109 from sensors 101, 102, 103 include, for example, flow pressure values ​​SD of the flow pressure sensor 101, atmospheric pressure values ​​AD of the atmospheric pressure sensor 102, and temperature values ​​TD of the temperature sensor 103. Sensors 101, 102, 103 output their sensor data or sensor values ​​as electrical values, for example, voltage values ​​or resistance values.

[0249] P 31363 / PCT

[0250] August 22, 2025 The volume flow measuring device 100 preferably has means for further processing the sensor data 109 of the pressure sensors 101, 102 and preferably of the temperature sensor 103.

[0251] For direct processing of the values ​​AD, SD, and TD, a processor 106 can be arranged on circuit board 112, which communicates with a memory 107, also arranged on circuit board 112. The processor 106 is optional and can be used to process the sensor data 109 provided by sensors 101, 102, and 103.

[0252] Furthermore, a communication interface 104 is provided on the volume flow measuring device 100 and / or the sensor carrier 110, which is designed and configured for communication with a communication interface 84 of a control unit 80 of the suction device 10. The communication interfaces 104 and 84 communicate with each other, for example, via a communication line 85, in particular a bus line.

[0253] The communication interfaces 104 and 84 are, for example, bus interfaces, in particular l 2C-Bus interfaces. Thus, the volume flow measuring device 100 can transmit the sensor data 109 from sensors 101, 102, 103 to the control unit 80 via the communication interfaces 104, 84. Therefore, for example, the processor 106 and the memory 107 are not strictly necessary; instead, the values ​​provided by sensors 101 to 103 can be processed by the control unit 80, which is already present in the suction device 10.

[0254] It is possible that the volume flow measuring device 100 and / or a processor on the sensor carrier 110 processes the sensor data 109 of the sensors 101, 102, 103 itself, for example using one or more program modules whose program code can be executed by the processor 106 of the volume flow measuring device 100.

[0255] The program module 90 described below can therefore be executed, for example, by processor 106 or processor 81. Program 90 is

[0256] P 31363 / PCT

[0257] For example, on August 22, 2025, the program code is stored in one of the memory locations 82 or 107 and contains program code that implements steps 91 to 96 of a procedure VF as explained below and is executable by the respective processor 81 or 106.

[0258] In step 91, for example, program module 90 records the atmospheric pressure value AD.

[0259] The atmospheric pressure value AD can, for example, be transmitted by the flow pressure sensor 101 before the suction unit 20 is switched on. This assumes that the suction unit 10 is regularly in a constant atmospheric pressure environment as long as it is operating. For example, step 91 can include first checking whether the suction unit 10 has been switched on for the first time, i.e., whether the control element 18 has been operated for the first time, and / or whether a power supply for the suction unit 10 is available in principle, for example, whether a power cord of the suction unit is plugged into a power supply network, and / or whether an energy storage device, in particular a battery pack, is being used for the first time to supply power to the suction unit 10.

[0260] Alternatively, it is also possible that atmospheric pressure values ​​AD provided by the atmospheric pressure sensor 102 or by an atmospheric pressure sensor 88 are recorded in step 91.

[0261] The atmospheric pressure sensor 88 is, for example, provided on board the control unit 80. Via the communication interface 84, the control unit 80 can transmit the pressure value provided by the atmospheric pressure sensor 88, for example, to an interface 108 of the volumetric flow meter 100 and / or the sensor carrier 110, which preferably forms part of the communication interface 104. Thus, for example, the volumetric flow meter 100 and / or the sensor carrier 110 do not need their own atmospheric pressure sensor 102, but can also obtain the atmospheric pressure value from another source.

[0262] Alternatively, a wireless interface and / or inter- can also be provided, for example, on board the control unit 80 and / or the sensor carrier 110.

[0263] P 31363 / PCT

[0264] A net interface will be provided on August 22, 2025, via which a respective atmospheric pressure value can be recorded and transmitted to the volume flow measuring device 100 and / or the sensor carrier 110.

[0265] In step 92, the flow pressure value SD is recorded by, for example, the volume flow measuring device 100 and / or the sensor carrier 110 and / or the control device 80 from the flow pressure sensor 101.

[0266] For example, the flow pressure value SD is first recorded when the suction unit 20 is switched on.

[0267] The control unit 80 first detects the flow pressure value SD when it switches on the suction unit 20.

[0268] It is also possible that the control unit 80 transmits a corresponding switch-on signal to the volume flow measuring unit 100 and / or the sensor carrier 110.

[0269] Furthermore, the flow-pressure sensor 101 will experience an increased pressure when the suction unit 20 is switched on, since the suction flow SD acts on the flow-pressure sensor 101. Therefore, a change in the pressure value of the flow-pressure sensor 101 is also an indicator that the suction unit 20 has been switched on and thus an indicator or start signal for recording the flow-pressure value SD.

[0270] In step 93, the procedure VF, which is represented by program module 90, provides that a difference, e.g. a differential pressure value DD, between the flow pressure value SD and the atmospheric pressure value AD is determined.

[0271] Such a differential pressure value DD is shown, for example, in the diagram according to Figure 10. For example, when the suction unit 20 is switched off, the differential pressure value DD is zero. When the suction unit 20 delivers maximum power and the at least one filter element 30 is sufficiently compressed, the differential pressure value DD is zero.

[0272] P 31363 / PCT

[0273] If the system is permeable on August 22, 2025, the differential pressure value DD can rise to, for example, 20 mbar.

[0274] In step 94, the procedure VF then provides to assign the differential pressure value DD according to figure 9 to a volume flow value V according to figure 9, using, for example, a table that is stored in memory 82 or 107.

[0275] Step 95 involves comparing the volume flow rate (V) with a volume flow limit (VG). Therefore, if the volume flow rate falls below a value specified by the volume flow limit (VG), step 96 issues a warning.

[0276] The warning, for example an acoustic and / or visual warning, is displayed by the suction device 10, for example on a display device 83, such as a loudspeaker or a visual display device. Of course, the display device 83 could also be a component of the volume flow measuring device 100.

[0277] From step 96, the procedure VF branches back to step 92 or step 91. If an atmospheric pressure sensor separate from the flow pressure sensor 101 is present, for example the atmospheric pressure sensor 102 and / or the atmospheric pressure sensor 88, step 91 is performed first, i.e., an atmospheric pressure value AD is acquired.

[0278] However, if no such atmospheric pressure sensor is available and / or no internet interface or other interface for recording an atmospheric pressure value provided by a third party, the program module 90 branches directly to step 92 and uses the atmospheric pressure value AD that was already recorded for the first time during the first run of the procedure VF.

[0279] For example, program module 90 is repeated cyclically to determine the most up-to-date volume flow value V.

[0280] P 31363 / PCT

[0281] August 22, 2025. When the program module 90 branches back from step 96 to step 91, thus recording a current atmospheric pressure value AD in each step, this is indicated by a return jump R1 in Figure 8, while the branching from step 96 to step 92 is represented as a return jump R2.

[0282] Furthermore, it is advantageous if program module 90, or a separate program module, is provided, which contains program code executable by processor 81 or processor 106. During the execution of this program, the temperature values ​​TD provided by temperature sensor 103 are compared with a temperature limit value, and if the temperature limit value is exceeded, the display device 83 is activated to issue a warning. Such a comparison of sensor values ​​or sensor data with limit values ​​corresponds analogously to steps 95 and 96 of procedure VF. For example, if a temperature limit value is exceeded, the suction unit 20 is overheated or at risk of overheating.

[0283] By way of example, it should be mentioned that a differently arranged sensor configuration is also possible for carrying out the VF method. For instance, a schematically indicated Venturi nozzle 200 can be arranged in the flow channel 45, in particular in the flow section 56, in which a flow pressure sensor 201, functionally corresponding to the flow pressure sensor 101, is arranged.

[0284] In the embodiment shown in Figures 1 to 7, the flow guide body 121 is oriented in the flow channel 45 such that the inlet opening 123 faces the suction flow S in the flow direction SR. This effectively forms a Pitot tube.

[0285] Even if the filter arrangement, e.g., the filter elements 30, the main filter 31, and the additional filter 32, has so to speak cleaned the suction flow S in the area of ​​the volume flow measuring device 100, i.e., that no particles or only minimally few particles are contained in the suction flow S, some particles still get through.

[0286] P 31363 / PCT

[0287] August 22, 2025 Time in small quantity of particles, dust particles or the like, through the inlet opening 123 onto the flow pressure sensor 101.

[0288] The embodiment described below takes this problem into account:

[0289] In the embodiment shown in Figures 10 and 11, the flow guide body 121 is oriented such that the inlet opening 123 is located on a side facing away from the suction flow S. Flow guide bodies 121 A and 121 B, of which one would of course suffice, are shown as examples in Figure 10 and schematically in Figure 4. The flow guide bodies 121 A and 121 B are closed on their side facing the suction flow S, where they are also exposed to the suction flow S in the flow direction SR, and guide the suction flow S past the flow pressure sensor 101.

[0290] The flow guide bodies 121 A, 121 B are arranged and designed such that the flow pressure sensor 101 is open to the influence of pressure on a side facing away from the flow direction SR of the suction flow S.

[0291] For example, each flow guide body 121 A, 121 B has a wall 128 on a side facing the suction flow S. The flow pressure sensor 101 is arranged on a side of the wall 128 facing away from the suction flow S, namely on the base 126.

[0292] The pipe body or pipe section 122 ensures that the suction flow S is guided past the flow pressure sensor 101 at the flow guide bodies 121 A, 121 B.

[0293] Only in the case of turbulence or similar conditions that could cause particles to flow through the inlet opening 123 could individual particles potentially reach the flow pressure sensor 101 at the flow guide bodies 121 A, 121 B. However, in this case, the protective layer 105 or the gel protects the flow pressure sensor 101.

[0294] P 31363 / PCT

[0295] August 22, 2025. The suction flow S cannot leave the suction unit 20 on the downstream side in the direction of the suction flow outlet 63 without obstruction. Firstly, the outlet filter 33 presents a flow obstruction, and secondly, so does the design of the flow channel 45. Even if the outlet filter 33 is not present, which is a preferred embodiment shown in the drawing by dashed lines representing the outlet filter 33, and / or a grid 33A, which may have only a low flow resistance, is arranged at the suction flow outlet 63, the channel routing and design of the flow channel 45 lead to a pressure build-up on the downstream side of the suction unit 20 or the suction turbine 22. This pressure can then be measured by the flow pressure sensor 101 in the flow guide body 121 A, 121 B.

[0296] For example, the arrangement of the channel sections 61, 62 is such that they form a flow obstruction 66 for the suction flow S. The suction flow S is deflected at least once in the channel sections 61, 62, which leads to a pressure increase in the area of ​​the flow pressure sensor 101 located in the flow guide body 121 A or 121 B.

[0297] The suction flow S can optimally flow past the measuring projection 120 in the orientation shown in Figure 11. The measuring projection 120 has a streamlined shape in this respect. For example, a flow separation edge or flow separation contour 129 is formed in the area of ​​the inlet opening 123.

[0298] The remaining functions of the volume flow measuring device 100 are the same for the flow guide bodies 121 A and 121 B as already described. In particular, the value of the respective volume flow is determined based on the evaluation of the sensor values ​​of the flow pressure sensor 101 and the atmospheric pressure sensor 102, which may be optionally provided. A different volume flow value may be assigned in step 94 of the procedure according to Figure 8 if the flow guide bodies 121 A or 121 B are arranged in the flow channel 45 with their orientation to protect the flow pressure sensor 101.

[0299] P 31363 / PCT

[0300] August 22, 2025

Claims

Claims 1. A suction device (10) with a vacuum housing (11) in which a dust collection chamber (14) for collecting dust (ST) and a suction unit (20) for generating a suction flow (S) are arranged, wherein the suction device (10) has a suction inlet (15) through which the suction flow (S) can flow into the dust collection chamber (14) and a suction flow outlet (S) through which the suction flow (S) can flow out of the vacuum housing (11), wherein the suction unit (20) is arranged between the suction inlet (15) and the suction flow outlet (63), and wherein at least one filter element (30) for separating dust (ST) from the suction flow (S) is arranged between the suction unit (20) and the dust collection chamber (14), and wherein the suction unit (20) is arranged in a flow channel (45) between the at least one filter (30) and the suction flow outlet (63), and wherein the The suction device (10) has a volume flow measuring device (100) for determining a volume flow value (V) of the suction flow (S),wherein the volume flow measuring device (100) has a flow pressure sensor (101) for determining a flow pressure value (SD), wherein the flow pressure sensor (101) is flow-connected to the flow channel (45) such that, when the suction unit (20) is in operation, the suction flow (S) acts on the flow pressure sensor (101) to generate a flow pressure, characterized in that the flow pressure sensor (101) is arranged in the flow channel (45) of the suction device (10) and the volume flow measuring device (100) has at least one flow guide element (121) for guiding the suction flow (S) with respect to the flow pressure sensor (101), in particular past the flow pressure sensor (101). P 31363 / PCT August 22, 2025 2. Suction device (10) according to claim 1 , characterized in that the flow guide body (121 ) is closed on a side facing the suction flow (S) and / or the flow guide body (121 ) is arranged in the flow channel (45) of the suction device (10) and / or projects into the flow channel (45).

3. Suction device according to claim 1 or 2, characterized in that the flow guide body (121 ) encloses the flow pressure sensor (101) except for an inlet opening (123) which is oriented away from the suction flow (S) or against the flow direction (SR) of the suction flow (S).

4. Suction device (10) according to one of the preceding claims, characterized in that the flow channel (45) downstream of the flow guide body (121 ) or the flow pressure sensor (101 ) has at least one flow obstruction (66), in particular a narrowing and / or deflection, for the suction flow (S) to generate a pressure acting on the flow pressure sensor (101 ).

5. Suction device (10) according to claim 4, characterized in that the at least one flow obstruction (66) is arranged at a distance from the suction flow outlet (63) and / or is arranged between the suction flow outlet (63) and the suction unit (20).

6. Suction device (10) according to one of the preceding claims, characterized in that the flow pressure sensor (101) is arranged downstream of the suction unit (20).

7. Suction device (10) according to one of the preceding claims, characterized in that the flow guide body (121) has at least one pipe body or pipe section (122), in particular a Pitot tube (125), with an inlet opening (123) through which pressure generated by the suction flow (S) can act on the flow pressure sensor (101), and a closed end region opposite the inlet opening (123), in particular a bottom, on which the flow pressure sensor (101) is arranged. P 31363 / PCT August 22, 2025 8. Suction device (10) according to claim 7, characterized in that a flow cross-section of the pipe section (122), in particular of the Pitot tube, is at least twice as large as a base area of ​​the flow-pressure sensor (101) and / or at least 12 mm² 2 amounts.

9. Suction device (10) according to claim 7 or 8, characterized in that the inlet opening (123) in the flow channel (45) faces the suction flow (S) so that the suction flow (S) can flow through the pipe section (122) to the flow pressure sensor (101) and / or is dammed up in front of it, or the inlet opening (123) in the flow channel (45) faces away from the suction flow (S) so that the pipe section (122) directs the suction flow (S) past the flow pressure sensor (101).

10. Suction device (10) according to one of the preceding claims, characterized in that the flow guide body (121) has flow contours (124A) for guiding the suction flow (S) past the pipe section (122) or pitot tube (125).

11. Suction device (10) according to one of the preceding claims, characterized in that the flow guide body (121) has a fin-like or wing-like shape and / or has at least one flow separation contour (124B) on its rear side in relation to the flow direction (SR) of the suction flow (S).

12. Suction device (10) according to one of the preceding claims, characterized in that the flow guide body (121) has a streamlined shape and / or that the flow guide body (121) has a rounded shape on its side facing the suction flow (S) and a narrower narrow side and / or a tear-off contour on its side facing away from the suction flow (S) compared to the rounded shape.

13. Suction device (10) according to one of the preceding claims, characterized in that at least one of the sensors of the volume flow measuring device (100), in particular the flow pressure sensor (101), is mounted on a sensor- P 31363 / PCT August 22, 2025 carrier (110) is arranged, which can be detachably connected to the suction housing (11).

14. Suction device (10) according to claim 13, characterized in that the sensor carrier (110) has at least one flange (113, 114) for support on a wall (64) of the suction device housing (11) which in particular defines a flow channel (45) for the suction flow (S), in particular flanges (113, 114) opposite each other and defining a receiving groove (115) for the wall (64) of the suction device (10).

15. Suction device (10) according to claim 13 or 14, characterized in that the sensor carrier (110) has or forms the flow guide body (121).

16. Suction device (10) according to one of claims 13 to 15, characterized in that the sensor carrier (110) consists at least partially of an elastic material, in particular of rubber or a rubber-like material.

17. Suction device (10) according to one of claims 13 to 16, characterized in that the sensor carrier (110) has a circuit board (112) on which at least one of the sensors, in particular the flow pressure sensor (101), of the volume flow measuring device (100) is arranged, wherein the circuit board (112) is wholly or at least partially embedded in an elastic material or is wholly or at least partially encased by an elastic material.

18. Suction device (10) according to one of the preceding claims, characterized in that the volume flow measuring device (100) has at least one temperature sensor (103), which is preferably arranged on the sensor carrier (110) and / or outside a detection area of ​​the flow-pressure sensor (101) which is pressurized due to the suction flow (S) and / or outside a pipe body or pipe section (122) in which the flow-pressure sensor (101) is arranged. P 31363 / PCT August 22, 2025 19. Suction device (10) according to one of the preceding claims, characterized in that the flow pressure sensor (101) is protected against water and / or other environmental influences and / or has a pressure measuring membrane coated with a protective layer (105), in particular a gel, for protection against water and / or other environmental influences.

20. Suction device (10) according to one of the preceding claims, characterized in that the flow channel (45) in the area of ​​the volume flow measuring device (100) and / or in the area of ​​the flow pressure sensor (101) has no constriction and / or has a constant cross-section.

21. Suction device (10) according to one of the preceding claims, characterized in that the flow channel (45) in the area of ​​the flow pressure sensor (101) has a straight shape and / or is designed as a channel for guiding a pipe flow and / or channel flow.

22. Suction device (10) according to one of the preceding claims, characterized in that the volume flow measuring device (100) is designed to determine an atmospheric pressure value (AD), in particular on the basis of the atmospheric pressure sensor (102), wherein the atmospheric pressure value (AD) represents an atmospheric pressure in the vicinity of the suction device (10), and that the volume flow measuring device (100) is designed to determine a volume flow value (V) representing a volume flow of the suction flow (S) on the basis of a difference between the flow pressure value (SD) and the atmospheric pressure value (AD).

23. Suction device (10) according to claim 22, characterized in that the volume flow measuring device (100) and / or the flow pressure sensor (101) is designed and provided for determining the atmospheric pressure value (AD) before switching on the suction unit (20).

24. Suction device (10) according to claim 22 or 23, characterized in that the volume flow measuring device (100) determines the atmospheric pressure value (AD) on the basis of the flow pressure sensor (101) and / or the flow- P 31363 / PCT August 22, 2025 mung pressure sensor (101 ) the only pressure sensor provided or available for determining the volume flow value (V) of the volume flow measuring device (100) is.

25. Suction device (10) according to one of the preceding claims, characterized in that it has an atmospheric pressure sensor (102) separate from the flow pressure sensor (101) for determining the atmospheric pressure value (AD).

26. Suction device (10) according to one of the preceding claims, characterized in that the volume flow measuring device (100) for determining the volume flow value (V) during operation of the suction unit (20) by determining a respective difference between the flow-pressure sensor (101) provided flow pressure values ​​(SD) and, in particular, atmospheric pressure values ​​(AD) provided by the atmospheric pressure sensor (102).

27. Suction device (10) according to one of the preceding claims, characterized in that the volume flow measuring device (100) or a sensor carrier (110) having at least the flow pressure sensor (101) is designed as a module detachably arranged on the suction device (10).

28. Suction device (10) according to one of the preceding claims, characterized in that the volume flow measuring device (100) has at least one computing unit and / or at least one processor (81 , 106) for determining the volume flow value (V) representing a volume flow of the suction flow (S) and / or an interface, in particular a communication interface (104), for determining the atmospheric pressure value (AD).

29. Suction device (10) according to one of the preceding claims, characterized in that the suction unit (20) is arranged in a suction unit receiving chamber (23) of the suction housing (11) and blows the suction flow (S) into a discharge duct (50) which is arranged on the suction unit receiving chamber (23) of the suction housing (11), wherein the P 31363 / PCT August 22, 2025 The discharge channel (50) extends in a ring-shaped manner around the suction unit receiving space (23) of the suction unit housing (11) from an initial region (52) of the discharge channel (50) to a channel outlet (54) of the discharge channel (50) provided for the outflow of the suction flow (S), and wherein a flow cross-section (SG) of the discharge channel (50) increases in particular continuously from its initial region (52) to the channel outlet (54) of the discharge channel (50).

30. Suction device (10) according to claim 29, characterized in that the initial area (52) is arranged directly next to the channel outlet (54).

31. Suction device (10) according to claim 29 or 30, characterized in that the initial region (52) and the channel outlet (54) are separated from each other by a tongue projecting to an outer circumference (22B) of the suction unit (20) or a tongue-like wall projecting to an outer circumference (22B) of the suction unit (20).

32. Suction device (10) according to one of claims 29 to 31, characterized in that the discharge channel (50) extends spirally and / or completely around the suction unit receiving chamber (23) with the exception of the channel outlet (54).

33. Suction device (10) according to one of claims 29 to 32, characterized in that the suction unit (20) has discharge openings (22C) opposite a circumferential wall (55) limiting the discharge channel (50), wherein the discharge openings (22C) are advantageously oriented to blow out the suction flow (S) tangentially in the direction of flow (SR) of the suction flow (S).

34. Suction device (10) according to one of claims 29 to 33, characterized in that the channel outlet (54) opens into a section of the flow channel (45) or is flow-connected to a flow section (56) of the flow channel (45) which is designed and / or provided for forming a pipe flow and / or channel flow of the suction flow (S) and / or ei- P 31363 / PCT August 22, 2025 has a straight course and / or a substantially constant flow cross-section over a longitudinal length that is at least equal to its transverse width.

35. Suction device (10) according to one of claims 29 to 34, characterized in that a volume flow measuring device (100) or the volume flow measuring device (100) is arranged in the flow section (56) of the flow channel (45).

36. Volume flow measuring device (100) for determining a volume flow value (V) of a suction flow (S) of a suction device (10) comprising a vacuum cleaner housing (11) in which a dust collection chamber (14) for collecting dust (ST) and a suction unit (20) for generating the suction flow (S) are arranged, wherein the vacuum cleaner (10) has a suction inlet (15) through which the suction flow (S) can flow into the dust collection chamber (14) and a suction flow outlet (S) through which the suction flow (S) can flow out of the vacuum cleaner housing (11), wherein the suction unit (20) is arranged between the suction inlet (15) and the suction flow outlet (63) and at least one filter element (30) for separating dust (ST) from the suction flow (S) is arranged between the suction unit (20) and the dust collection chamber (14), and wherein the suction unit (20) is in a flow channel (45) is arranged between at least one filter (30) and the suction flow outlet (63),wherein the volume flow measuring device (100) has a flow pressure sensor (101) for determining a flow pressure value (SD), wherein the flow pressure sensor (101) is flow-connected to the flow channel (45) such that, when the suction unit (20) is in operation, the suction flow (S) acts on the flow pressure sensor (101) to generate a flow pressure, characterized in that the flow pressure sensor (101) is designed and provided for arrangement in the flow channel (45) of the suction device (10) and the volume flow measuring device (100) has at least one flow guide element (121) for guiding the suction flow (S) with respect to the flow pressure sensor (101), in particular past the flow pressure sensor (101). P 31363 / PCT August 22, 2025 37. Method for measuring volume flow using the suction device (10) according to one of the preceding claims, characterized by: - Determination of a flow pressure value (SD) using a flow pressure sensor (101) of the volume flow measuring device (100), wherein the flow pressure sensor (101) is flow-connected to the flow channel (45) such that when the suction unit (20) is in operation, the suction flow (S) acts on the flow pressure sensor (101) to generate a flow pressure. - Determination of an atmospheric pressure value (AD) using the volume flow measuring device (100), in particular using an atmospheric pressure sensor (102), wherein the atmospheric pressure value (AD) represents an atmospheric pressure in the vicinity of the suction device (10), and - Determination of a volume flow value (V) representing a volume flow of the suction flow (S) based on a difference between the flow pressure value (SD) and the atmospheric pressure value (AD) by the volume flow measuring device (100).

38. Program module comprising program code executable by a processor (81 , 106), the execution of which by the processor (81 , 106) makes the method according to claim 37 executable. P 31363 / PCT August 22, 2025

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