Patent Publication Number: US-2021187333-A1

Title: Blower device for a respiratory protection system

Description:
STATE OF THE ART 
     The invention concerns a blower device for a respiratory protection system. 
     A blower device for a respiratory protection system, with a fan for generating an airflow and with at least one filter element that is configured to be flowed through by the airflow, has already been proposed. 
     The objective of the invention is in particular to provide a generic device with improved characteristics regarding a compactness and a comfort. The objective is achieved according to the invention by the features of patent claim  1  while advantageous implementations and further developments of the invention may be gathered from the subclaims. 
     Advantages of the Invention 
     The invention is based on a blower device for a respiratory protection system, with a fan for generating an airflow and with at least one filter element that is configured to be flowed through by the airflow. 
     It is proposed that the fan is arranged at least partly beside the at least one filter element, wherein the airflow is deflected between the fan and the filter element. Preferably the filter element and the fan are arranged in a common housing. Preferentially the housing forms defined ducts for guiding the airflow. Preferably the airflow between the fan and the filter element is deflected by at least 50°, preferentially by at least 90°, preferably by at least 140° and particularly preferably by at least 180°. The blower device is in particular implemented by a compact blower device. The blower device is in particular configured to be worn on the body, for example on the back and/or on the hip. 
     By a “blower device” is in particular, in this context, a device to be understood which is configured for an active generation of an airflow for supplying a user with breathing air. The blower device is in particular configured, in an operation, for feeding the airflow to a mouth protection device of the respiratory protection system. The blower device is preferentially connected with the mouth protection device of the respiratory protection system via at least one breathing air supply line. Preferably the blower device is configured, in an operation, for suctioning air from an environment, for purifying, in particular filtering, the air and for feeding the purified air to a user actively, in particular via the mouth protection device. Preferably the blower device is configured for generating an active airflow. The blower device is in particular configured for generating a positive-pressure airflow. The fan is in particular, in an operation, configured for an active suctioning of air from an environment and for an active transport of the air to the mouth protection device of the respiratory protection system. The fan is in particular implemented by an axial fan and/or radial fan. By a “filter element” is in particular, in this context, an element to be understood which is configured, in an operation, for a filtering of the airflow. For this purpose the filter element preferably comprises a filter, which is in an operation flowed through by the airflow. Preferentially the airflow flows through the filter of the filter element completely. The filter element is in particular configured for separating off particles, in particular suspended matter, from the airflow. Herein different filters are conceivable which are deemed expedient by someone skilled in the art. Preferably the filter of the filter element is in particular implemented by a suspended-matter filter. Preferably the filter is embodied as a depth filter or cake filter, in particular as a lamellate filter. 
     By “the fan being arranged at least partly beside the at least one filter element” is in particular to be understood, in this context, that, in a direction that is perpendicular to a main extension plane of the fan, the fan is free from a complete cover by the filter element. Preferentially a normal vector of the main extension plane of the fan, which extends through a geometric center of the fan, is free of an intersection point with the filter element. Preferably the fan and the filter element are arranged side by side in a main extension plane of the blower device. Preferentially, viewed perpendicularly to the main extension plane of the blower device, the fan and the filter element are implemented to be at least substantially free, in particular completely free, of a mutual covering. By a “main extension plane” of a structural unit is in particular a plane to be understood which is parallel to a largest side face of a smallest imaginary rectangular cuboid just still completely enclosing the structural unit, and which in particular extends through the center point of the rectangular cuboid. “At least substantially” is in particular to mean, in this context, that a deviation from a given value is in particular less than 25%, preferably less than 10% and particularly preferably less than 5% of the given value. 
     By the “airflow being deflected between the fan and the filter element” is in particular to be understood, in this context, that in an operation of the blower device the airflow changes its direction on its way between the filter element and the fan. The “direction” of the airflow is in particular to mean, in this context, an averaged movement direction of the particles of the airflow in a point. Preferably a guide duct is arranged between the filter element and the fan, which is configured for guiding the airflow, wherein the guide duct is configured for a defined deflection of the airflow. Preferentially the guide duct forms a deflection between the filter element and the fan. The deflection may, for example, be effected in the shape of a curve, a bending, a kink, or the like. Preferably an inflow axis and/or an inflow direction of the airflow into the guide duct is essentially different and/or substantially offset from an outflow axis and/or an outflow direction of the airflow out of the guide duct. “Configured” is in particular to mean specifically programmed, designed and/or equipped. By an object being configured for a certain function is in particular to be understood that the object fulfills and/or executes said certain function in at least one application state and/or operation state. 
     The implementation according to the invention in particular enables providing an advantageously compact, in particular flat, blower device. It is in particular possible to do without a direct stacking of the fan and the filter unit. This in particular allows achieving an advantageously small construction height of the blower device. 
     Furthermore it is proposed that a flow-through direction of the airflow through the filter element is substantially different from a flow-through direction of the airflow through the fan. Preferably the flow-through direction of the airflow through the fan is perpendicular or parallel to a main extension plane of the fan. Preferably the flow-through direction of the airflow through the filter element is perpendicular to a main extension plane of the filter element. Preferentially the flow-through direction of the filter element is angled relative to the flow-through direction of the fan by at least 50°, preferably by at least 90°, preferentially by at least 140° and especially preferentially by at least 180°. Preferably the flow-through direction of the filter element is at least approximately opposed to the flow-through direction of the fan. In this way in particular a deflection of the airflow is achievable. Preferentially this in particular enables providing an advantageously compact, in particular flat-built, blower device. It is in particular possible to avoid direct stacking of the fan and the filter unit. As a result, in particular an advantageously small construction height of the blower device is achievable. 
     It is moreover conceivable that the flow-through direction of the airflow through the filter element is at least substantially opposed to the flow-through direction of the airflow through the fan. “At least substantially opposed” is in particular to mean, in this context, that a direction vector of the flow-through direction of the airflow through the fan includes a smallest angle of at least 140°, preferably at least 160° and particularly preferably at least approximately 180° with the direction vector of the flow-through direction of the airflow through the filter element. In this way in particular an advantageous side-by-side arrangement of the fan and the filter element is achievable. As a result, it is in particular possible to provide an advantageously compact, in particular flat-built, blower device. In particular, direct stacking of the fan and the filter unit is avoidable. In this way in particular an advantageously small construction height of the blower device is achievable. 
     It is further proposed that the at least one filter element has a main extension plane and the fan has a main extension plane, wherein a distance from the main extension plane of the filter element to the main extension plane of the fan is smaller than a maximum thickness of the filter element. The filter element preferably extends parallel to the fan. Preferentially a distance from the main extension plane of the filter element to the main extension plane of the fan is smaller than 50 mm, preferably smaller than 30 mm and particularly preferably smaller than 10 mm. The main extension plane of the filter element and the main extension plane of the fan are preferably arranged in a plane. In this way in particular an advantageously compact arrangement of the fan and the filter element is achievable. This in particular enables providing an advantageously compact, in particular flat-built, blower device. 
     Moreover it is proposed that the at least one filter element has a main extension plane and the fan has a main extension plane, wherein at least a large portion of normal vectors of the main extension plane of the filter element, which intersect with the filter element, is free of an intersection point with the fan. Preferentially all normal vectors of the main extension plane of the filter element, which intersect with the filter element, are free of an intersection point with the fan. The filter element and the fan may in particular be arranged side by side and parallel to one another, as well as side by side and partly angled relative to one another. An angle between the main extension plane of the filter element and the main extension plane of the fan is preferentially greater than 80°, preferably greater than 120° and particularly preferably greater than 160°. By “at least a large portion of normal vectors, which intersect with the filter element” at least such normal vectors are to be understood which intersect with more than 50%, preferably more than 70% and particularly preferably more than 90% of a main extension area of the filter element. In this way in particular an advantageously compact arrangement of the fan and the filter element is achievable. This in particular enables providing an advantageously compact, in particular flat-built, blower device. 
     It is also proposed that the blower device comprises a further filter element, which is arranged beside the fan and/or beside the one filter element and whose flow-through direction of the airflow differs from a flow-through direction of the airflow through the fan and/or through the filter element. Preferentially the further filter element is arranged beside the fan and beside the filter element. Furthermore the flow-through direction of the airflow through the further filter element preferably differs from a flow-through direction of the airflow through the fan. In this way in particular an advantageously compact arrangement of the fan, the filter element and the further filter element is achievable. This in particular enables providing an advantageously compact, in particular flat-built, blower device. 
     Furthermore it is proposed that the at least one filter element has a main extension plane and the fan has a main extension plane, wherein the main extension plane of the filter element is angled relative to the main extension plane of the fan. Preferably an angle between the main extension plane of the filter element and the main extension plane of the fan is greater than 45°, preferentially greater than 60° and especially preferentially greater than 75°. Preferably a normal vector of the main extension plane of the filter element, which intersects with the filter element, and a normal vector of the main extension plane of the fan, which intersects with the fan, include an angle of maximally 90° and minimally 5°. An intersection line of the main extension plane of the filter element and the main extension plane of the fan preferably extends at least in a proximity of the filter element and the fan. A smallest distance between the intersection line and the filter element is in particular smaller than 15 cm, preferentially smaller than 10 cm and especially preferentially smaller than 5 cm. In this way in particular an advantageously compact arrangement of the fan and the filter element is achievable. This in particular enables providing an advantageously compact, in particular flat-built, blower device. 
     Beyond this it is proposed that the blower device comprises a housing unit, which accommodates the fan and the at least one filter element and has a thickness of less than 70 mm. Preferably the housing unit has a thickness of less than 50 mm. The housing unit in particular serves for a protection and an orientation of the fan and of the filter element. Preferentially the blower device further comprises an energy storage for an energy supply of the fan, which is also accommodated in the housing unit. A “thickness” of the housing unit is in particular to mean, in this context, a maximum extension of the housing unit perpendicularly to a main extension plane of the housing unit. This in particular enables providing an advantageously compact blower device. 
     It is also proposed that the fan is configured for a generation of a volumetric flow rate of the airflow of at least 50 l/min and maximally 250 l/min. Preferentially the fan is configured for a generation of a volumetric flow rate of the airflow of at least 80 l/min and maximally 120 l/min. This in particular enables providing an advantageously compact high-performance blower device. 
     Furthermore it is proposed that the fan hat at least one inlet, through which the airflow is sucked into the fan, wherein a flow-in direction of the airflow into the fan is at least substantially opposed to a flow-in direction of the airflow into the filter element. In particular, the fan is implemented by a radial fan, such that air is sucked axially into the fan. An axis of rotation of the fan extends in particular at least substantially perpendicularly to a main extension plane of the filter element. The airflow in particular flows through the filter element, is then deflected towards the fan, preferably on a rear wall of the housing unit, and is then sucked into the fan in the region of the fan perpendicularly to the rear wall. An airflow flowing into the filter element therefore in particular flows towards the rear wall, while the air flow flowing into the fan is oriented away from the rear wall. The flow-in direction of the airflow into the fan is angled relative to the flow-in direction of the airflow into the filter element, in particular by at least 100°, preferably at least 120° and more preferably at least 140°. The flow-in direction of the airflow into the fan is in particular angled by at least approximately 170° with respect to the flow-in direction of the airflow into the filter element. In this way in particular an advantageous side-by-side arrangement of the fan and the filter element is achievable. As a result, it is in particular possible to provide an advantageously compact, in particular flat-built, blower device. In particular, direct stacking of the fan and the filter unit is avoidable. In this way in particular an advantageously small construction height of the blower device is achievable. 
     It is also proposed that the housing unit has a rear wall, having a flow guiding body which is provided to guide the airflow when flowing into the fan. The rear wall is formed in particular by a housing shell of the housing unit facing the user. In an operation, the rear wall of the housing unit in particular rests on a user&#39;s back. In this context, a “flow guiding body” is in particular to be understood as a volume body which is configured for a selective guidance and control of the airflow. The flow guiding body preferably protrudes into a flow channel of the airflow between the filter element and the fan. The flow guiding body is preferably configured to deflect an air flow, with an airflow in particular being calmed when deflected. The flow guiding body in particular has a flow guiding surface, which is provided to be flowed against by an airflow. The airflow is deflected from the flow guiding surface by at least 30°, preferably by at least 60° and particularly preferably by at least 90° towards an inlet of the fan. In this way in particular an advantageous side-by-side arrangement of the fan and the filter element is achievable. As a result, it is in particular possible to provide an advantageously compact, in particular flat-built, blower device. Preferably, an advantageously relaxed airflow into the fan can be implemented. In particular, an advantageous flow onto a flow sensor can be provided. 
     Beyond this it is proposed that the flow guiding body has a flow guiding wall which has, in a cross-section perpendicular to a flow-in direction of the fan, a spiral-sector-shaped course. A radius of the course of the flow guiding wall preferably decreases towards the inlet of the fan. A flow sensor is preferably arranged on an inlet side of the flow guiding wall. The flow guiding wall is in particular a wall of the flow guiding body facing the flow channel of the air flow. In particular, the flow guiding body is directly arranged next to the fan. The flow guiding body is preferably directly arranged next to the fan in a region of the inlet of the fan. As a result, it is in particular possible to provide an advantageously compact, in particular flat-built, blower device. Preferably, an advantageously relaxed air flow into the fan can be implemented. In particular, an advantageous flow onto a flow sensor can be provided. 
     The invention is furthermore based on a respiratory protection system, in particular a respiratory protection blower system, with the blower device and with at least one mouth protection device. It is proposed that the at least one blower device is configured for a generation of a positive pressure in the mouth protection device. Preferably the at least one blower device is configured for generating, in the mouth protection device, a positive pressure relative to an environment. A “respiratory protection system” is in particular to mean, in this context, a system with a blower device and with a mouth protection device, which is configured to actively provide an airflow for a breathing air supply of a user. The respiratory protection system is in particular configured, in an operation, to generate an airflow by means of a blower device, which is fed to the mouth protection device of the respiratory protection system. Preferentially the blower device is connected with the mouth protection device of the respiratory protection system via at least one breathing air supply line. Preferably the respiratory protection system is configured, in an operation, for suctioning air from an environment, for purifying, in particular filtering, the air and for actively feeding the purified air to a user by means of the mouth protection device. By a “mouth protection device” is in particular, in this context, a device to be understood which implements a mouth protection and which is configured to be worn at least on a mouth and/or nose region of a user. Preferentially the device is configured to form a breathing region in front of a user&#39;s mouth and/or nose region, which is in an operation continuously supplied with breathing air. Preferably the mouth protection device is configured to supply a user with breathing air directly and to protect the user&#39;s mouth and/or nose region from external influences, in particular from gases, particles and/or suspended matter. Preferentially the mouth protection device is free of a covering a user&#39;s eyes, in particular of a user&#39;s eye area. Preferably the mouth protection device comprises a mask base body, which is configured to cover a user&#39;s mouth and/or nose region and which at least partly delimits a breathing region, and comprises at least one breathing air supply line that is connected with the mask base body and delimits at least one breathing air duct, which opens into the breathing region and is configured for guiding an active breathing airflow. 
     This in particular enables providing an advantageously comfortable respiratory protection system. In particular, a reliable supply with breathing air is achievable. 
     Moreover it is proposed that the respiratory protection system comprises a vest that is to be worn by a user, on the back of which the blower device is arranged. Preferentially the blower device is releasably connected with the vest. This in particular allows ensuring an advantageously comfortable wearing of the respiratory protection system. Furthermore it is in particular possible to achieve an advantageous arrangement of the blower device. In particular, a slipping of the blower device can be avoided. 
     Beyond this it is proposed that the respiratory protection system comprises an external operating unit comprising at least one operating element and at least one control and/or regulation unit, which is configured for a control and/or regulation of the blower device. Preferably the external operating unit is connected with the blower device via a radio connection and/or by a cable. The external operating unit is in particular implemented by a remote control. It would however also be conceivable that the external operating unit is implemented with a smartphone or something like that. By an “operating unit” is here in particular a unit to be understood which comprises at least one operating element that is directly operable by a user, and which is configured for influencing and/or changing a process and/or a state of a unit that is coupled with the operating unit by an activation and/or by entering parameters. By an “operating element” is in particular an element to be understood which is configured, in an operating process, to receive an input parameter from a user and in particular to be contacted by a user directly, wherein a touching of the operating element is sensed and/or an activation force applied to the operating element is sensed and/or is mechanically transmitted for an activation of a unit. A “control and/or regulation unit” is in particular to mean a unit with at least one control electronics part. A “control electronics part” is in particular to mean a unit with a processor unit and with a memory unit and with an operation program that is stored in the memory unit. In this way in particular an advantageously comfortable controlling of the blower device is achievable. 
     It is further proposed that the external operating unit comprises at least one sensor unit for capturing at least one environment parameter, wherein the control and/or regulation unit is configured, in at least one operation state, for a control and/or regulation of the blower device on the basis of the at least one environment parameter. Different environment parameters which are deemed expedient by someone skilled in the art are conceivable. 
     Preferentially, for example, an air quality, an ambient pressure, an oxygen concentration or something similar is captured by the sensor unit. The external operating unit is in particular configured to be worn by a user on his chest. It is thus in particular possible to capture environment parameters in a user&#39;s head region by means of the sensor unit. By a “sensor unit” is in particular, in this context, a unit to be understood which is configured to record at least one parameter and/or a physical characteristic, wherein the recording may take place actively, in particular by generating and emitting an electric measurement signal, and/or passively, in particular by capturing changes in a characteristic of a sensor component. Different sensor units which are deemed expedient by someone skilled in the art are conceivable. This in particular enables achieving a sensible control and/or regulation of the blower device. In particular, an adapted operation of the blower device is achievable. It would furthermore be conceivable that a user may be warned, for example of dangerous situations. 
     The blower device according to the invention, the respiratory protection system and/or the external operating unit are/is herein not to be limited to the application and implementation described above. In particular, for the purpose of fulfilling a functionality that is described here, the blower device according to the invention, the respiratory protection system and/or the external operating unit may comprise a number of individual elements, structural components and units that differs from a number that is given here. Moreover, regarding the value ranges given in the present disclosure, values situated within the limits mentioned shall also be considered to be disclosed and to be insertable as applicable. 
    
    
     
       DRAWINGS 
       Further advantages will become apparent from the following description of the drawings. The drawings show two exemplary embodiments of the invention. The drawings, the description and the claims contain a plurality of features in combination. Someone skilled in the art will purposefully also consider the features individually and will find further expedient combinations. 
       It is shown in: 
         FIG. 1  a respiratory protection system with a blower device, with a mouth protection device, with a vest and with an external operating unit, and a user, in a schematic representation, 
         FIG. 2  the blower device of the respiratory protection system in a schematic plan view, 
         FIG. 3  the blower device of the respiratory protection system, with a fan and with a filter element, in a schematic sectional view along the section line II-II. 
         FIG. 4  the mouth protection device of the respiratory protection system and a user&#39;s head in a schematic representation, 
         FIG. 5  the mouth protection device of the respiratory protection system in a schematic partial sectional view, 
         FIG. 6  a partial section of the mouth protection device of the respiratory protection system in a schematic sectional view, 
         FIG. 7  an alternative blower device of a respiratory protection system, with a fan, with a filter element and with a further filter element, in a schematic sectional view, 
         FIG. 8  a further alternative blower device of a respiratory protection system, with a housing unit, with a fan and with a filter element, in a schematic exploded view, 
         FIG. 9  a rear wall of the housing unit of the further alternative blower device with a flow guiding body, in a schematic representation, and 
         FIG. 10  the rear wall of the housing unit of the further alternative blower device with the flow guiding body, in a schematic plan view. 
     
    
    
     DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a respiratory protection system  10   a . The respiratory protection system  10   a  is implemented by a respiratory protection blower system. The respiratory protection system  10   a  is in particular implemented by a respiratory protection blower system having the safety class TH3. The respiratory protection system  10   a  is configured for a protection of a user  18   a  from particles like smoke, aerosols and/or dust. Furthermore the respiratory protection system  10   a  is additionally capable of protecting from disgusting smells and toxic ozone. In particular it is conceivable that, in environments containing gases which are harmful to health or even toxic, the respiratory protection system  10   a  protects the user  18   a  from organic, inorganic and/or acidic gases. The respiratory protection system  10   a  comprises a blower device  14   a  and a mouth protection device  12   a . The blower device  14   a  is configured for generating a breathing airflow  26   a . The blower device  14   a  is configured for generating a breathing airflow  26   a  for the mouth protection device  12   a.    
     The blower device  14   a  comprises a housing unit  58   a . The housing unit  58   a  is implemented by a synthetic housing. The housing unit  58   a  comprises two interconnected housing shells  70   a ,  72   a , namely a first housing shell  70   a  and a second housing shell  72   a . The first housing shell  70   a  comprises two openable covers  74   a ,  76   a , via which an inner space of the housing unit  58   a  can be made accessible. The second housing shell  72   a  forms a rear side of the housing unit  58   a , which in a state when worn faces toward the user  18   a . The second housing shell  72   a  is concavely curved on its outer side. The curvature of the second housing shell  72   a  is adapted to the curvature of a human back. Furthermore the housing unit  58   a  comprises a plurality of air inlet openings  78   a . The air inlet openings  78   a  are formed by slits in the first housing shell  70   a . In an operation the air inlet openings  78   a  serve for suctioning ambient air via an airflow  50   a . The housing unit  58   a  further comprises an air outlet opening  80   a . The air outlet opening  80   a  is formed by a hose connecting piece on the first housing shell  70   a . In an operation the air outlet opening  80   a  serves for outputting the purified airflow  50   a , in particular a breathing airflow  26   a . In an operation the breathing airflow  26   a  is transferred from the air outlet opening  80   a  onwards to the mouth protection device  12   a  ( FIGS. 1, 2 ). 
     The housing unit  58   a  has a thickness d of less than 70 mm. The housing unit  58   a  has a thickness d of less than 50 mm. 
     The blower device  14   a  moreover comprises a fan  48   a  for a generation of an airflow  50   a . The blower device  14   a  is configured to generate a positive pressure in the mouth protection device  12   a . The fan  48   a  is configured to generate a positive pressure in the mouth protection device  12   a . The fan  48   a  is configured to generate a volumetric flow rate of the airflow  50   a  of at least 50 l/min and maximally 250 l/min. The fan  48   a  is configured to generate a volumetric flow rate of the airflow  50   a  of at least 80 l/min and maximally 120 l/min. In an operation the blower device  14   a  is configured to generate in the mouth protection device  12   a , by means of the fan  48   a , a relative positive pressure with respect to an environment. The fan  48   a  is implemented by an electric radial fan. Principally, however, another implementation deemed expedient by someone skilled in the art would also be conceivable. The fan  48   a  is arranged in the housing unit  58   a . A main extension plane  56   a  of the fan  48   a  extends at least substantially parallel to a main extension plane of the housing unit  58   a . The fan  48   a  is arranged in an upper region of the blower device  14   a . The air outlet opening  80   a  is arranged on an output side of the fan  48   a . The blower device  14   a  further comprises a control and/or regulation unit  86   a  for a controlling and/or regulation of the fan  48   a  in an operation. The control and/or regulation unit  86   a  is in particular configured for an automatic adaption of a performance level of the fan  48   a . The control and/or regulation unit  86   a  is configured to adjust an airflow level of the fan  48   a  depending on a saturation of a filter element  52   a . Furthermore the control and/or regulation unit  86   a  is in particular configured for an automatic airflow control and airflow adaption ( FIG. 3 ). 
     The blower device  14   a  further comprises the filter element  52   a . The filter element  52   a  is configured to be flown through by the airflow  50   a . The filter element  52   a  is implemented by a rectangular-cuboid-shaped filter module. The filter element  52   a  is implemented by a suspended-matter filter. The filter element  52   a  is embodied as a depth filter, in particular a lamellate filter. However, it would also be conceivable for the filter element  52   a  to be embodied as a gas filter, in particular as an A1B1E1 gas filter. The filter element  52   a  is arranged in the housing unit  58   a . A main extension plane  54   a  of the filter element  52   a  extends at least substantially parallel to a main extension plane of the housing unit  58   a . The filter element  52   a  is arranged in a lower region of the blower device  14   a . The housing unit  58   a  accommodates the fan  48   a  and the filter element  52   a . The air inlet opening  78   a  is arranged on an entry side of the filter element  52   a . Furthermore the filter element  52   a  is implemented in such a way that it is exchangeable via the cover  74   a  ( FIG. 3 ). 
     The fan  48   a  is arranged beside the filter element  52   a , wherein the airflow  50   a  is deflected between the fan  48   a  and the filter element  52   a . The filter element  52   a  and the fan  48   a  are together arranged in the housing unit  58   a . The housing unit  58   a  comprises an air guide duct  82   a , which accommodates the filter element  52   a  and is configured for guiding the airflow  50   a  between the filter element  52   a  and the fan  48   a . In terms of fluid dynamics, the filter element  52   a  is arranged before the fan  48   a  along the airflow  50   a . The airflow  50   a  between the fan  48   a  and the filter element  52   a  is deflected by at least approximately 90°. A deflection of the airflow  50   a  is effected in the air guide duct  82   a . It would, however, also be conceivable that an air guide duct  82   a  may be dispensed with. A flow-through direction r 1  of the airflow  50   a  through the filter element  52   a  is substantially different from a flow-through direction r 2  of the airflow  50   a  through the fan  48   a . The flow-through direction r 2  of the airflow  50   a  through the fan  48   a  extends parallel to the main extension plane  56   a  of the fan  48   a . In case of an implementation of the fan  48   a  as an axial fan, it would also be conceivable that the flow-through direction r 2  of the airflow  50   a  through the fan  48   a  extends perpendicularly to the main extension plane  56   a  of the fan  48   a . The flow-through direction r 1  of the airflow  50   a  through the filter element  52   a  extends perpendicularly to the main extension plane  54   a  of the filter element  52   a . The flow-through direction r 1  of the filter element  52   a  is angled by at least approximately 90° relative to the flow-through direction r 2  of the fan  48   a  ( FIG. 3 ). 
     The filter element  52   a  has the main extension plane  54   a . The fan  48   a  has the main extension plane  56   a . It would be conceivable for the main extension plane  54   a  to extend parallel to the main extension plane  56   a , wherein a distance from the main extension plane  54   a  of the filter element  52   a  to the main extension plane  56   a  of the fan  48   a  is smaller than a maximum thickness of the filter element  52   a . Preferably, in a parallel implementation a distance from the main extension plane  54   a  of the filter element  52   a  to the main extension plane  56   a  of the fan  48   a  would be smaller than 50 mm, preferentially smaller than 30 mm and especially preferentially smaller than 10 mm. In the illustrated implementation the main extension plane  54   a  of the filter element  52   a  is angled relative to the main extension plane  56   a  of the fan  48   a . An angle between the main extension plane  54   a  of the filter element  52   a  and the main extension plane  56   a  of the fan  48   a  is greater than 80°, preferably greater than 120° and particularly preferably greater than 160°. The angle between the main extension plane  54   a  of the filter element  52   a  and the main extension plane  56   a  of the fan  48   a  is at least approximately 165°. A normal vector of the main extension plane  54   a  of the filter element  52   a , which intersects with the filter element  52   a , and a normal vector of the main extension plane  56   a  of the fan  48   a , which intersects with the fan  48   a , include a smallest angle of at least approximately 15°. Preferentially the main extension plane  56   a  of the fan  48   a  and the main extension plane  54   a  of the filter element  52   a  include a smallest angle of at least 60°, preferably at least 70°, with an imaginary plane in which the intersection line between the main extension plane  56   a  of the fan  48   a  and the main extension plane  54   a  of the filter element  52   a  extends and which is situated symmetrically between the filter element  52   a  and the fan  48   a . Preferentially an intersection line of the main extension plane  54   a  of the filter element  52   a  and the main extension plane  56   a  of the fan  48   a  extends in a proximity of the filter element  52   a  and the fan  48   a . A smallest distance between the intersection line and the filter element  52   a  is in particular smaller than 15 cm, preferably smaller than 10 cm and particularly preferably smaller than 5 cm. A smallest distance between he intersection line and the filter element  52   a  is smaller than a smallest distance between the fan  48   a  and the filter element  52   a . At least a large portion of normal vectors of the main extension plane  54   a  of the filter element  52   a , which intersect with the filter element  52   a , are free of an intersection point with the fan  48   a . All normal vectors of the main extension plane  54   a  of the filter element  52   a , which intersect with the filter element  52   a , are free of an intersection point with the fan  48   a . The filter element  52   a  and the fan  48   a  are arranged, at least partially angled relative to one another, side by side ( FIG. 3 ). 
     Beyond this the blower device  14   a  comprises an energy storage  84   a . The energy storage  84   a  is implemented by a rechargeable battery. The energy storage  84   a  serves for an energy supply of the fan  48   a . A main extension plane of the energy storage  84   a  extends at least substantially parallel to a main extension plane of the housing unit  58   a . The energy storage  84   a  is arranged in a lower region of the blower device  14   a . The housing unit  58   a  accommodates the fan  48   a , the filter element  52   a  and the energy storage  84   a . The housing unit  58   a  serves for a protection and an orientation of the fan  48   a , the filter element  52   a  and the energy storage  84   a . The energy storage  84   a  is furthermore implemented in such a way that it is exchangeable via the cover  76   a  ( FIG. 3 ). 
     The respiratory protection system  10   a  further comprises an external operating unit  62   a . The external operating unit  62   a  is implemented by a remote control. The operating unit  62   a  comprises operating elements  64   a  and a control and/or regulation unit  66   a , which is configured for a control and/or regulation of the blower device  14   a . The external operating unit  62   a  is exemplarily connected with the blower device  14   a  by a cable  88   a . The control and/or regulation unit  66   a  of the external operating unit  62   a  is in particular configured to actuate the control and/or regulation unit  86   a  of the blower device  14   a  depending on an input at the operating elements  64   a . It is for example possible to set a performance level of the fan  48   a  via the operating elements  64   a . It is furthermore possible to activate or deactivate the fan  48   a  via the operating elements  64   a . The external operating unit  62   a  moreover comprises a sensor unit  68   a  for capturing environment parameters. The control and/or regulation unit  66   a  is configured, in at least one operation state, for a control and/or regulation of the blower device  14   a  on the basis of the environment parameters. The control and/or regulation unit  66   a  is configured, in an operation, to actuate the control and/or regulation unit  86   a  of the blower device  14   a , wherein a performance level of the fan  48   a  is adapted on the basis of the environment parameters by means of the control and/or regulation unit  86   a  of the blower device  14   a . The sensor unit  68   a  is configured to capture an air quality, an ambient pressure and/or an oxygen concentration. 
     The respiratory protection system  10   a  further comprises a vest  60   a  that is to be worn by a user  18   a . The vest  60   a  is implemented by a fabric vest. The blower device  14   a  is arranged on a rear side of the vest  60   a . In an operation, the blower device  14   a  is worn by a user  18   a  on his back by means of the vest  60   a . In an operation, the blower device  14   a  is worn by a user  18   a  on his back by means of the vest  60   a . The external operating unit  62   a  is furthermore configured to be worn by a user  18   a  on his chest. The external operating unit  62   a  is arranged on a front side of the vest  60   a . It is therefore possible that environment parameters are captured in a head region of the user  18   a  via the sensor unit  68   a.    
     The respiratory protection system  10   a  further comprises a breathing air line  46   a , which is configured for guiding the breathing airflow  26   a . The breathing air line  46   a  connects the blower device  14   a  with the mouth protection device  12   a . The breathing air line  46   a  is connected with the blower device  14   a  via the air outlet opening  80   a  of the blower device  14   a . The breathing air line  46   a  is implemented by a hose. In an operation the breathing air line  46   a  is configured for guiding the breathing airflow  26   a.    
     The mouth protection device  12   a  comprises a mask base body  16   a . The mask base body  16   a  is configured for covering a mouth and nose region of the user  18   a . Furthermore the mask base body  16   a  is configured to at least partially delimit a breathing region  20   a . In an operation the mask base body  16   a , together with the face of the user  18   a  and a separation layer  38   a , delimits the breathing region  20   a . The mask base body  16   a  is implemented at least to a large extent of a flexurally soft material. The mask base body  16   a  is completely implemented of a flexurally soft material. The mask base body  16   a  is completely implemented of a dimensionally unstable material. The mask base body  16   a  is implemented at least to a large extent of a textile material. The mask base body  16   a  is completely implemented of a textile material. The mask base body  16   a  is made of a textile. The mask base body  16   a  is completely implemented of a textile. The mask base body  16   a  is implemented to be at least substantially airtight. It would in particular be conceivable that a textile of which the mask base body  16   a  is made comprises a coating which at least reduces an air permeability. The mask base body  16   a  is airtight in particular at least at an absolute pressure of 1 bar, preferably at least 2 bar and particularly preferably at least 3 bar ( FIG. 4 ). 
     The mouth protection device  12   a  further comprises a sealing element  90   a . The sealing element  90   a  is fixedly connected with the mask base body  16   a . The sealing element  90   a  is arranged at an upper edge of the mask base body  16   a . The sealing element  90   a  is configured for sealing the mask base body  16   a , at least at an upper edge of the mask base body  16   a , against the face of the user  18   a . The sealing element  90   a  is configured for sealing the breathing region  20   a  and an outlet region  40   a  toward the eyes of the user  18   a , in order to avoid an airflow into the eyes of the user  18   a . The sealing element  90   a  is made of a foam material. The sealing element  90   a  is implemented of a foam strip. The sealing element  90   a  is exemplarily glued with the mask base body  16   a  ( FIG. 6 ). 
     Furthermore the mouth protection device  12   a  comprises a breathing air supply line  22   a , which is connected with the mask base body  16   a . The breathing air supply line  22   a  delimits a breathing air duct  24   a  which opens into the breathing region  20   a  and which is configured to guide the active breathing airflow  26   a . The breathing air supply line  22   a  is implemented of an elastic hose. The breathing air supply line  22   a  exemplarily has an oval cross section. However, a different cross section of the breathing air supply line  22   a , deemed expedient by someone skilled in the art, would also be conceivable, for example a circular cross section. The breathing air supply line  22   a  extends from the breathing air line  46   a  to the breathing region  20   a.    
     The mouth protection device  12   a  also comprises a further breathing air supply line  22 ′ a , which is redundant to the breathing air supply line  22   a  and is connected with the mask base body  16   a . The further breathing air supply line  22 ′ a  delimits a further breathing air duct, which opens into the breathing region  20   a  and is configured for guiding an active breathing airflow  26   a . The further breathing air supply line  22 ′ a  is implemented of an elastic hose. The further breathing air supply line  22 ′ a  exemplarily has an oval cross section. The further breathing air supply line  22 ′ a  extends from the breathing air line  46   a  to the breathing region  20   a . The further breathing air supply line  22 ′ a  is arranged on a side of the mask base body  16   a  that faces away from the breathing air supply line  22   a . The breathing air supply lines  22   a ,  22 ′ a  are configured to be guided past the head  30   a  of the user  18   a  on different sides of the head  30   a  of the user  18   a . The further breathing air supply line  22 ′ a  has a function that is redundant to the breathing air supply line  22   a . The further breathing air supply line  22 ′ a  serves to augment a safety of a supply with the breathing airflow  26   a . The breathing air supply line  22   a  and the further breathing air supply line  22 ′ a  are each functional independently from one another. 
     The breathing air line  46   a  connected with the blower device  14   a  is configured for guiding the breathing airflow  26   a  to the breathing air supply lines  22   a ,  22 ′ a . The breathing air line  46   a  is furthermore configured for dividing the breathing airflow  26   a  to the breathing air supply line  22   a  and the further breathing air supply line  22 ′ a . The breathing air line  46   a  is coupled with the breathing air supply line  22   a  and the further breathing air supply line  22 ′ a  via a Tee connector piece  108   a . The Tee connector piece  108   a  is configured to be arranged in a nape region of the user  18   a.    
     The mouth protection device  12   a  further comprises a fixation strap  28   a  for a fixation of the mask base body  16   a  on the head  30   a  of the user  18   a . The fixation strap  28   a  is implemented of an elastic strap, like in particular a rubber strap. The fixation strap  28   a  has a width which at least approximately corresponds to a width of the breathing air supply line  22   a . Furthermore an effective length of the fixation strap  28   a  is implemented to be adjustable. The fixation strap  28   a  extends from a first end of the mask base body  16   a  to an opposite-situated second end of the mask base body  16   a . The fixation strap  28   a  extends from a first end of the mask base body  16   a , in which the breathing air supply line  22   a  is connected with the mask base body  16   a , to an opposite-situated second end of the mask base body  16   a , in which the further breathing air supply line  22 ′ a  is connected with the mask base body  16   a . The fixation strap  28   a  is configured, in a state when the mouth protection device  12   a  is worn, to be guided around a back of the head, in particular in a nape region. The mouth protection device  12   a  comprises at least one connection unit  32   a  for a simultaneous plug connection of the fixation strap  28   a  and the at least one breathing air supply line  22   a ,  22 ′ a  with the mask base body  16   a . The mouth protection device  12   a  comprises the connection unit  32   a  and a further connection unit, which is not shown, for a simultaneous plug connection of the fixation strap  28   a  respectively with the breathing air supply line  22   a  and the mask base body  16   a , and with the further breathing air supply line  22 ′ a  and the mask base body  16   a . The connection units  32   a  serve for pulling off or taking off the mouth protection device  12   a . In the connection units  32   a  a coupling is effected, for example, by means of a plugging movement. The connection units  32   a  each comprise a first coupling element  92   a  and a second coupling element  94   a  that corresponds to the first coupling element  92   a . The first coupling elements  92   a  of the connection units  32   a  exemplarily each form an interface receptacle, while the second coupling elements  94   a  of the connection units  32   a  each form an interface extension. The first coupling elements  92   a  of the connection units  32   a  are each fixedly connected with the mask base body  16   a  at opposite ends. The second coupling element  94   a  of the connection units  32   a  is fixedly connected with a first end of the fixation strap  28   a  and with the breathing air supply line  22   a . The further second coupling element of the further connection unit is fixedly connected with a second end of the fixation strap  28   a  and with the further breathing air supply line  22 ′ a . The first coupling elements  92   a  of the connection units  32   a  are respectively implemented of a hose connection. The first coupling elements  92   a  of the connection units  32   a  are respectively configured to latch with the second coupling elements  94   a  of the connection units  32   a . The second coupling elements  94   a  of the connection units  32   a  each comprise actuation elements  96   a  for a releasing of the latch connection ( FIGS. 1, 5 ). 
     The mouth protection device  12   a  comprises a head fixation strap  98   a  for an additional fixation of the mask base body  16   a  on the head  30   a  of the user  18   a . Furthermore, an effective length of the head fixation strap  98   a  is implemented adjustable. The head fixation strap  98   a  extends from a first end of the mask base body  16   a  to an opposite-situated second end of the mask base body  16   a . The head fixation strap  98   a  extends from a first end of the mask base body  16   a , in which the breathing air supply line  22   a  is connected with the mask base body  16   a , to an opposite-situated second end of the mask base body  16   a , in which the further breathing air supply line  22 ′ a  is connected with the mask base body  16   a . The head fixation strap  98   a  is configured, in a state when the mouth protection device  12   a  is worn, to be guided around a back of a head, in particular an upper head. The mouth protection device  12   a  comprises a fixation unit  100   a  and a further fixation unit  100 ′ a  for an adjustable fixation of the head fixation strap  98   a  with the mask base body  16   a  at its ends. For a fixation, the head fixation strap  98   a  is guided adjustably on the fixation units  100   a ,  100 ′ a  through recesses. 
     The mouth protection device  12   a  also comprises an adjustment unit  34   a , wherein at least an effective length of a side edge  36   a  of the mask base body  16   a  is implemented to be at least partly adjustable by means of said adjustment unit  34   a . An effective length of a side edge  36   a  from the first end of the mask base body  16   a , in which the first coupling element  92   a  is arranged, to the second end of the mask base body  16   a , in which the further first coupling element  92 ′ a  is arranged, is implemented to be adjustable by means of the adjustment unit  34   a . The side edge  36   a  extends substantially parallel to a main extension direction of the mask base body  16   a . The adjustment unit  34   a  comprises a cord  102   a , in particular an elastic cord, as well as a cord clamp  104   a . The cord  102   a  of the adjustment unit  34   a  extends in a duct of the mask base body  16   a  from the first end of the mask base body  16   a  to the second end of the mask base body  16   a , which is situated opposite the first end. The cord  102   a  is fixated at the first end and the second end. An effective length of the cord  102   a , and thus of the side edge  36   a  of the mask base body  16   a , is implemented to be manually adjustable by means of the cord clamp  104   a . In particular, an effective length of the cord  102   a  is implemented to be manually adjustable by way of different-sized loops of the cord  102   a  being formed by means of the cord clamp  104   a.    
     The mouth protection device  12   a  furthermore comprises a separation layer  38   a , which is connected with the mask base body  16   a  and is configured for at least partly separating the breathing region  20   a  from an outlet region  40   a . The outlet region  40   a  is at least partially delimited by the mask base body  16   a . The outlet region  40   a  is arranged below the breathing region  20   a . In an operating state the mask base body  16   a  delimits, together with the face of the user  18   a , a spatial region that is divided by the separation layer  38   a  into a breathing region  20   a  and an outlet region  40   a . The separation layer  38   a  forms, together with the mask base body  16   a , a duct which at least partially forms the breathing region  20   a  and which extends up to a middle region of the mouth protection device  12   a . The duct formed by the separation layer  38   a  extends from the breathing air duct  24   a  and the further breathing air duct to a user&#39;s mouth and/or nose region. In the user&#39;s mouth and/or nose region the breathing region  20   a  merges into the outlet region  40   a . The separation layer  38   a  is realized integrally with the mask base body  16   a . The separation layer  38   a  protrudes, perpendicularly to the mask base body  16   a , between the breathing region  20   a  and the outlet region  40   a . The separation layer  38   a  has in a middle region a cutout  106   a , which connects the breathing region  20   a  with the outlet region  40   a . The separation layer  38   a  is at least substantially made of a textile material. The separation layer  38   a  is completely made of a textile. The separation layer  38   a  is configured for a defined guidance of air. The separation layer  38   a  is configured to guide the breathing airflow  26   a  past the mouth and/or nose region of a user  18   a  before reaching the outlet region  40   a . For this purpose the separation layer  38   a  has in its middle region the cutout  106   a , which connects the breathing region  20   a  with the outlet region  40   a . In an operation, the breathing airflow  26   a  flows from the breathing air duct  24   a  and the further breathing air duct into the breathing region  20   a , and from the breathing region  20   a  through the cutout  106   a  into the outlet region  40   a . The cutout  106   a  is arranged in a proximity of the mouth and/or nose region of a user  18   a  ( FIG. 6 ). 
     Beyond this the mouth protection device  12   a  comprises a discharge valve  42   a , which is configured to regulate a pressure in the breathing region  20   a  to an at least approximately constant value. The discharge valve  42   a  is embodied by a positive-pressure valve, in particular a one-way positive-pressure valve, which is configured to open from a defined positive pressure in the breathing region  20   a , respectively the outlet region  40   a , relative to an environment. The discharge valve  42   a  is configured to permit, in particular to keep up, a defined positive pressure in the breathing region  20   a . Preferably the discharge valve  42   a  is embodied by a mechanical valve. The mask base body  16   a  is not completely sealed against the face of the user  18   a  such that, besides the discharge valve  42   a , there is a transition between the mask base body  16   a  and the face, where it is also possible for air to escape. In case of too much leakage or in case of the mouth protection device  12   a  taken off, the pressure in the breathing region  20   a  can no longer be kept up at the transition from the mask base body  16   a  to the face, and the pressure falls below the limit value of the discharge valve  42   a . This can be captured by the blower device  14   a , in particular on the basis of a load of the fan  48   a , and a warning signal may be outputted to the user  18   a  if applicable. It is in this way possible that a faulty wearing of the mouth protection device  12   a  is indicated to the user  18   a . Moreover, the fan  48   a  may thus stop automatically if the mouth protection device  12   a  is put on. Under regular conditions the pressure in the breathing region  20   a  is regulated to an approximately constant value by means of the discharge valve  42   a  ( FIG. 4 ). 
     It is moreover conceivable that the mask base body  16   a  comprises a partial region  44   a , which is implemented to be permeable to air. The partial region  44   a  is in particular made of an air-permeable textile. The partial region  44   a  is directly adjacent to the outlet region  40   a . The partial region  44   a  serves for a defined discharge of air into the outlet region  40   a . The partial region  44   a  is provided in addition to the discharge valve  42   a  but it would also be conceivable that only the partial region  44   a  is provided, the partial region  44   a  adopting the function of the discharge valve  42   a.    
       FIGS. 7 to 10  show two further exemplary embodiments of the invention. The following description will be essentially limited to the differences between the exemplary embodiments, wherein regarding structural components, features and functions which remain the same the description of the exemplary embodiment of  FIGS. 1 to 6  may be referred to. To distinguish between the exemplary embodiments, the letter a added to the reference numerals of the exemplary embodiment of  FIGS. 1 to 6  has been substituted by the letters b and c in the reference numerals of the exemplary embodiments of  FIGS. 7 to 10 . In regard to structural components having the same denomination, in particular regarding structural components having the same reference numerals, principally the drawings and/or the description of the exemplary embodiment of  FIGS. 1 to 6  may be referred to. 
       FIG. 7  shows a blower device  14   b  of a respiratory protection system. The blower device  14   b  is configured for a generation of a breathing airflow  26   b . The blower device  14   b  is configured for a generation of a breathing airflow  26   b  for a mouth protection device. 
     The blower device  14   b  comprises a housing unit  58   b . The housing unit  58   b  is embodied by a synthetic housing. The housing unit  58   b  comprises two interconnected housing shells  70   b ,  72   b , namely a first housing shell  70   b  and a second housing shell  72   b . The housing unit  58   b  has a thickness d of less than 70 mm. 
     Furthermore the blower device  14   b  comprises a fan  48   b  for generating an airflow  50   b . The blower device  14   b  is configured to generate a positive pressure in the mouth protection device  12   b . The fan  48   b  is configured to generate a positive pressure in the mouth protection device  12   b . The fan  48   b  is embodied by an electric radial fan. 
     The blower device  14   b  further comprises a filter element  52   b . The filter element  52   b  is configured to be flown through by the airflow  50   b . The filter element  52   b  is implemented by a rectangular-cuboid-shaped filter module. The filter element  52   b  is embodied by a suspended-matter filter. The filter element  52   b  is embodied as a depth filter, in particular as a lamellate filter. A main extension plane  54   b  of the filter element  52   b  extends at least substantially parallel to a main extension plane of the housing unit  58   b . The filter element  52   b  is arranged in a lower region of the blower device  14   b . The housing unit  58   b  accommodates the fan  48   b  and the filter element  52   b.    
     The blower device  14   b  also comprises a further filter element  52 ′ b . The further filter element  52 ′ b  is configured to be flown through by the airflow  50   b . The further filter element  52 ′ b  is configured to be flown through by the airflow  50   b  before the filter element  52   b . The further filter element  52 ′ b  is implemented by a rectangular-cuboid-shaped filter module. The further filter element  52 ′ b  is implemented by an activated-carbon odor filter. A main extension plane  54 ′ b  of the further filter element  52 ′ b  extends at least substantially parallel to a main extension plane of the housing unit  58   b . The further filter element  52 ′ b  is arranged in a lower region of the blower device  14   b . The housing unit  58   b  accommodates the fan  48   b , the filter element  52   b  and the further filter element  52 ′ b . Air inlet openings  78   b  are arranged on an entry side of the further filter element  52 ′ b . The further filter element  52 ′ b  is arranged on an entry side of the filter element  52   b.    
     The fan  48   b  is arranged beside the filter element  52   b , wherein the airflow  50   b  is deflected between the fan  48   b  and the filter element  52   b . The further filter element  52 ′ b  is also arranged beside the fan  48   b . The filter element  52   b , the further filter element  52 ′ b  and the fan  48   b  are together arranged in the housing unit  58   b . The housing unit  58   b  comprises an air guide duct  82   b  accommodating the filter element  52   b  and the further filter element  52 ′ b , which is configured for guiding the airflow  50   b  between the filter element  52   b  and the fan  48   b . The filter element  52   b  and the further filter element  52 ′ b  are arranged in a stacked fashion. In terms of fluid dynamics, the filter element  52   b  is arranged before the fan  48   b  along the airflow  50   b . In terms of fluid dynamics, the further filter element  52 ′ b  is arranged before the filter element  52   b  along the airflow  50   b . The airflow  50   b  is deflected by at least approximately 90° between the fan  48   b  and the filter element  52   b . A deflection of the airflow  50   b  is effected in the air guide duct  82   b . It would however also be conceivable that an air guide duct  82   b  can be done without. A flow-through direction r 1  of the airflow  50   b  through the filter element  52   b  is essentially different from a flow-through direction r 2  of the airflow  50   b  through the fan  48   b . A flow-through direction r 3  of the airflow  50   b  through the further filter element  52 ′ b  is essentially different from a flow-through direction r 2  of the airflow  50   b  through the fan  48   b . The flow-through direction r 3  of the airflow  50   b  through the further filter element  52 ′ b  is substantially equivalent to the flow-through direction r 1  of the airflow  50   b  through the filter element  52   b . The flow-through direction r 2  of the airflow  50   b  through the fan  48   b  extends parallel to a main extension plane  56   b  of the fan  48   b . The flow-through direction r of the airflow  50   b  through the filter element  52   b  extends perpendicularly to the main extension plane  54   b  of the filter element  52   b . The flow-through direction r 3  of the airflow  50   b  through the further filter element  52 ′ b  extends perpendicularly to the main extension plane  54 ′ b  of the further filter element  52 ′ b . The flow-through direction r 1  of the filter element  52   b  and the flow-through direction r 3  of the further filter element  52 ′ b  are angled by at least approximately 90° relative to the flow-through direction r 2  of the fan  48   b.    
       FIG. 8  shows a blower device  14   c  of a respiratory protection system. The blower device  14   c  is configured for a generation of a breathing airflow. The blower device  14   c  is configured for a generation of a breathing airflow  26   c  for a mouth protection device. 
     The blower device  14   c  comprises a housing unit  58   c . The housing unit  58   c  is embodied by a synthetic housing. The housing unit  58   c  comprises two interconnected housing shells  70   c ,  72   c , namely a first housing shell  70   c  and a second housing shell  72   c . The housing unit  58   c  has a thickness d of less than 70 mm. The second housing shell  72   c  forms a rear wall  110   c  of the housing unit  58   c . In an operation, the rear wall  110   c  of the housing unit  58   c  in particular rests on a user&#39;s back. 
     Furthermore the blower device  14   c  comprises a fan  48   c  for generating an airflow  50   c . The blower device  14   c  is configured to generate a positive pressure in the mouth protection device. The fan  48   c  is configured to generate a positive pressure in the mouth protection device. The fan  48   c  is embodied by an electric radial fan. 
     The blower device  14   c  further comprises a filter element  52   c . The filter element  52   c  is configured to be flown through by the airflow  50   c . The filter element  52   c  is implemented by a rectangular-cuboid-shaped filter module. The filter element  52   c  is embodied by a suspended-matter filter. The filter element  52   c  is embodied as a depth filter, in particular as a lamellate filter. A main extension plane of the filter element  52   c  extends at least substantially parallel to a main extension plane of the housing unit  58   c . The filter element  52   c  is arranged in a lower region of the blower device  14   c . The housing unit  58   c  accommodates the fan  48   c  and the filter element  52   c . The fan  48   c  is arranged beside the filter element  52   c , wherein the airflow  50   c  is deflected between the fan  48   c  and the filter element  52   c.    
     The fan  48   c  is arranged beside the filter element  52   c , wherein the airflow  50   c  is deflected between the fan  48   c  and the filter element  52   c . The filter element  52   c  and the fan  48   c  are together arranged in the housing unit  58   c . The housing unit  58   c  comprises an air guide duct  82   c , which accommodates the filter element  52   c  and is configured for guiding the airflow  50   c  between the filter element  52   c  and the fan  48   c . In terms of fluid dynamics, the filter element  52   c  is arranged before the fan  48   c  along the airflow  50   c . The airflow  50   c  between the fan  48   c  and the filter element  52   c  is deflected by at least approximately 90°. A deflection of the airflow  50   c  is effected in the air guide duct  82   c . It would, however, also be conceivable that an air guide duct  82   c  may be dispensed with. A flow-through direction r 1  of the airflow  50   c  through the filter element  52   a  is substantially different from a flow-through direction r 2  of the airflow  50   c  through the fan  48   c . The flow-through direction r 2  of the airflow  50   c  through the fan  48   c  extends parallel to the main extension plane of the fan  48   c . In case of an implementation of the fan  48   c  as an axial fan, it would also be conceivable that the flow-through direction r 2  of the airflow  50   c  through the fan  48   c  extends perpendicularly to the main extension plane of the fan  48   c . A flow-in direction r 4  of the airflow  50   c  into the fan  48   c  extends perpendicularly to the main extension plane of the fan  48   c . A flow-out direction of the airflow  50   c  into the fan  48   c  extends parallel to the main extension plane of the fan  48   c . The flow-through direction r of the airflow  50   a  through the filter element  52   a  extends perpendicularly to the main extension plane  54   a  of the filter element  52   a . The flow-through direction r 1  of the filter element  52   a  is angled by at least approximately 90° relative to the flow-through direction r 2  of the fan  48   a  ( FIG. 3 ). The fan  48   c  hat at least one inlet  118   c , through which the airflow  50   c  is sucked into the fan  48   c . The inlet  118   c  is formed by an axial inlet. The flow-in direction r 4  of the airflow  50   c  into the fan  48   c  is at least substantially opposed to a flow-in direction r 5  of the airflow  50   c  into the filter element  52   c . The fan  48   c  is embodied by a radial fan, such that air is sucked axially into the fan  48   c . An axis of rotation of the fan  48   c  in particular extends at least substantially perpendicularly to a main extension plane of the filter element  52   c . The airflow  50   c  flows through the filter element  52   c , is then deflected towards the fan  48   c  by the air guide duct  82   c  and is then sucked into the fan  48   c  in the region of the fan  48   c  perpendicular to the main extension plane of the fan  48   c . An airflow  50   c  flowing into the filter element  52   c  therefore flows towards the rear wall  110   c , while the airflow  50   c  when flowing into the fan  48   c  is directed away from the rear wall  110   c . The flow-in direction r 4  of the air flow  50   c  into the fan  48   c  is angled by at least approximately 170° with respect to the flow-in direction r 5  of the air flow  50   c  into the filter element  52   c.    
     The rear wall  110   c  of the housing unit  58   c  has a flow guiding body  112   c  which is configured to guide the air flow  50   c  when flowing into the fan  48   c . The flow guiding body  112   c  protrudes into a flow channel of the air flow  50   c  between the filter element  52   c  and the fan  48   c . The flow guiding body  112   c  is configured to deflect an airflow  50   c , with an airflow  50   c  in particular being calmed when deflected. The flow guiding body  112   c  has a flow guiding wall  114   c , which is configured to be flowed against by an air flow  50   c . The airflow  50   c  is deflected from the flow guiding wall  114   c  by at least 90° towards the inlet  116   c  of the fan  48   c . The flow guiding wall  114   c  has, in a cross-section perpendicular to a flow-in direction r 4  of the fan  48   c , a spiral-sector-shaped course. A radius of the course of the flow guiding wall  114   c  decreases towards the inlet  118   c  of the fan  48   c . A flow sensor is arranged on an inlet side of the flow guiding wall  114   c . The flow sensor is arranged on a sensor mount  116   c  of the rear wall  110   c . The flow guiding wall  114   c  is a wall of the flow guiding body  112   c  facing the flow channel of the air flow  50   c . The flow guiding body  112   c  is directly arranged next to the fan  48   c . The flow guiding body  112   c  is preferably directly arranged next to the fan  48   c  in a region of the inlet  118   c  of the fan  48   c.    
     REFERENCE NUMERALS 
     
         
           10  respiratory protection system 
           12  mouth protection device 
           14  blower device 
           16  mask base body 
           18  user 
           20  breathing region 
           22  breathing air supply line 
           22 ′ breathing air supply line 
           24  breathing air duct 
           26  breathing airflow 
           28  fixation strap 
           30  head 
           32  connection unit 
           34  adjustment unit 
           36  side edge 
           38  separation layer 
           40  outlet region 
           42  discharge valve 
           44  partial region 
           46  breathing air line 
           48  fan 
           50  airflow 
           52  filter element 
           52 ′ filter element 
           54  main extension plane 
           54 ′ main extension plane 
           56  main extension plane 
           58  housing unit 
           60  vest 
           62  operating unit 
           64  operating element 
           66  control and/or regulation unit 
           68  sensor unit 
           70  housing shell 
           72  housing shell 
           74  cover 
           76  cover 
           78  air inlet opening 
           80  air outlet opening 
           82  air guide duct 
           84  energy storage 
           86  control and/or regulation unit 
           88  cable 
           90  sealing element 
           92  coupling element 
           94  coupling element 
           96  actuation element 
           98  head-fixation strap 
           100  fixation unit 
           100 ′ fixation unit 
           102  cord 
           104  cord clamp 
           106  cutout 
           108  T-connector 
           110  rear wall 
           112  flow guiding body 
           114  flow guiding wall 
           116  sensor mount 
           118  inlet 
         d thickness 
         r 1  flow-through direction 
         r 2  flow-through direction 
         r 3  flow-through direction 
         r 4  flow-in direction 
         r 5  flow-in direction