Ventilation device for wearing under clothing and method for creating an air flow on body parts

Abstract

A ventilation device for creating an air flow on body parts, which is provided and configured to be worn under items of clothing. The ventilation device comprises a plenum shell, which comprises a first wall and a second wall (12). The second wall has an inner side facing the first wall and an outer side facing away from the first wall. In the second wall there are a plurality of outflow ducts (121) which have a cumulative outlet cross-sectional area that corresponds to the sum of the respective smallest flow cross-sectional areas of each outflow duct. The ventilation device also comprises at least one blower which, on the pressure side, leads into a plenum (15), which plenum is formed in the plenum shell of the ventilation device. The plenum (15) is in fluid connection with the outflow ducts (121) and is delimited, on the pressure side of the at least one blower, by the outlet surface of the impeller of the at least one blower. A ratio of the volume of the plenum to the cumulative outlet cross-sectional area of the outflow ducts is 0.75 m or more.

Description

[0001] VENTILATION DEVICE FOR WEARING UNDER CLOTHING AND METHOD FOR CREATING AN AIR FLOW ON PARTS OF THE BODY

[0002] TECHNICAL FIELD

[0003] The present description relates to a ventilation device for creating an airflow on body parts, which is intended to be worn under clothing. Specifically, it is a ventilation device of the type described in the claims. Furthermore, a method for creating an airflow on body parts is described.

[0004] TECHNOLOGICAL BACKGROUND

[0005] To ensure passive safety, appropriate protective clothing is worn when performing a variety of activities that pose a risk of mechanical injury from external influences. Examples include protective clothing designed to prevent injuries caused by chainsaws when using a chainsaw, protective clothing for motorcyclists, and protective vests designed to protect wearers in both civilian and military settings from stab and / or gunshot wounds and other violent impacts. Of course, these examples are not exhaustive and are intended only to illustrate some of the areas in which protective clothing is worn. On the other hand, such protective clothing can lead to heat build-up under clothing, as ventilation and the release of evaporated sweat are impeded, and this clothing also shields the body from convective heat exchange with the environment.This can be particularly stressful for the wearer, especially in conjunction with physical activity and / or high outside temperatures. These consequences can range from a reduced sense of comfort for the wearer to reduced physical and mental performance in extreme cases, and even lead to serious physical consequences such as circulatory collapse and heatstroke. The increase in passive safety can thus be counteracted by a reduction in active safety, which may even overcompensate for the increase in passive safety. It is therefore desirable to provide suitable devices to ensure adequate cooling for the wearer of protective clothing.

[0006] Devices have become known that actively induce an airflow onto the skin of the wearer of protective clothing between the skin of the wearer of the protective clothing and the inside of the protective clothing, supporting the outflow of heated air enriched with evaporated sweat. Ventilating air above the wearer's skin enables heat to be released from the skin to the air, while removing air enriched with evaporated sweat promotes the evaporation of sweat. This allows the body's natural cooling mechanisms through the skin to function even under protective clothing. This helps avoid health risks for the wearer, maintain the wearer's performance, and increase or counteract a lack of well-being.When such devices are provided with an adjustable fan for applying the air flow, the wearer can, of course within the limits of the fan's performance and within the limits imposed by the temperature and humidity of the air conveyed by the fan, regulate the air ventilation in such a way as to be within his personal comfort zone with regard to skin temperature.

[0007] In this regard, it is also important to distribute the airflow as evenly as possible, or, in possible applications, specifically tailored to local perspiration production, across the exposed skin areas to avoid areas of skin that are not sufficiently cooled and thus not sufficiently airflowed, which would in turn be perceived as unpleasant. This even or tailored airflow results in the efficient use of the moving air and thus the energy used to drive the airflow for the purpose of evaporating sweat and dissipating moisture, thus creating a comfortable climate between the protective clothing and the body.

[0008] Various approaches are known from the prior art. US 2001 / 0000849 A1 discloses a cooling device for a human body in which channels open toward the body are passed through by an air flow generated by a fan in order to cool the body by the air passing over them. According to the teaching of US 2005 / 0066401 A1, air is directed by a fan through chambers, one side of the chamber being formed by an air-impermeable material and the other side being formed by an air-permeable material. The air-permeable material lies on the body, and the body is cooled by air flowing over and through the air-permeable material. The article proposed in WO 2005 / 118167 A2 comprises three layers: a bulletproof outer layer, a porous inner layer, and an intermediate layer.The intermediate layer is designed as a hollow space and is fed with air by a blower or fan. Holes in the side of the intermediate layer adjacent to the inner layer release the air from the intermediate layer into the inner layer, which rests on the body and further distributes the air to cool the body and absorbs perspiration. US 2020 / 0217584 A1 proposes a bulletproof vest in which double-walled tubes are arranged adjacent to or in contact with an innermost layer of material. A liquid is located in the innermost tube. Air, which can be cooled or heated, flows in the jacket space between the two walls of the tubes. The fluid within the innermost tube serves as a heat or cold source.

[0009] Cold storage in such a way that a heating or cooling effect can be achieved even when a temperature control unit, which drives the air in the shell space between the two walls of the tubes and regulates their temperature, is not in operation. US 2013 / 0319031 A1 proposes providing a plate-shaped fluid distributor. A surface with holes, or a mesh in the region of the spine, is provided adjacent to the body. Distribution channels within the fluid distributor guide an air flow to the holes or mesh, such that the air is directed through the holes or openings in the mesh onto the body. US 2019 / 0008219 A1 proposes providing air distribution channels which are closed off from the body by a perforated wall.Spacers are arranged on the outer side of the perforated wall, which is intended to be positioned toward the body, such that the wall with the outlet openings is spaced from the body when properly used. The distribution channels are fed by a fan or blower. US 2019 / 0008219 A1 further proposes that the size of the outlet openings increase in a downstream direction within the distribution channels. Furthermore, it is provided to arrange flow deflectors on the downstream sides of the outlet openings within the distribution channels to redirect the fluid flow into the outlet openings. Furthermore, it is proposed to introduce water droplets into the airflow for cooling purposes. At this point, the doctrine of US 2019 / 0008219 A1 relies on achieving a cooling effect through the evaporation of supplied water droplets rather than supporting the body's natural cooling mechanisms by promoting the evaporation of sweat.

[0010] US 11,656,061 B2 proposes a bomb disposal suit comprising a jacket, pants, and a back protector mounted between the jacket and pants. The back protector comprises a body made of impact-resistant material with a plenum with an intake port for receiving compressed air and with exhaust ports for directing compressed air from the plenum. A fan forces air into the intake port. The back protector can transfer the load vertically from the jacket to the pants, e.g., via a back plate.

[0011] DESCRIPTION OF THE SUBJECT OF THE PRESENT DESCRIPTION

[0012] The present invention proposes a ventilation device and a method for creating an airflow over body parts of the type described above. According to certain aspects of the present description, the proposed ventilation device is intended to provide an adjustable cooling effect through variable air ventilation over the skin, allowing the wearer of the ventilation device to adjust the cooling effect or cooling performance and regulate it to their own comfort level. The term "cooling performance" does not necessarily imply that the air used is cooled. In this sense, the "cooling performance" results from the interplay between the moving air, the flow of air over the wearer's skin, and the evaporation of sweat from the wearer's skin.According to further aspects, it should be ensured that the distribution of the air flow over the exposed skin area is predictable and - at least within the intended control range - influenced as little as possible by the set volume flow or mass flow of air. According to further aspects, the effectiveness of the ventilation device should also be taken into account, in the sense that the moving air used achieves a maximum cooling effect for the body under the given circumstances. According to a further aspect, the teaching disclosed here aims to promote the evaporation of sweat and the removal of air enriched with moisture by the evaporation of sweat, and to replace the air enriched with moisture by the evaporation of sweat with fresh air - or another suitable fluid - so that the sweat can evaporate easily at all times.This results in self-regulation of the cooling effect achieved by ventilation, since the skin, if it no longer requires local cooling, no longer produces sweat at that location, and cooling at that location is drastically reduced. In this way, in contrast to devices and methods that work with actively cooled fluid or through the evaporation of an externally supplied liquid, potential local or overall overcooling is counteracted, which in turn would result in reduced comfort and the potential for cold-induced illnesses.

[0013] Further effects and advantages of the teaching disclosed herein, whether explicitly stated or not, will become apparent in light of the present description.

[0014] This is achieved by means of the device specified in claim 1 and the method described in the independent method claim.

[0015] Accordingly, a ventilation device for creating an airflow on body parts is described, which is particularly intended and configured to be worn under clothing. For example, the ventilation device can be intended and configured to be worn on the upper body. The ventilation device can be worn directly on the skin; however, it can also be the case that another item of clothing, in particular one that absorbs or wicks away sweat, is worn between the ventilation device and the skin. The ventilation device comprises a plenum shell, which in turn comprises a first wall and a second wall. The second wall is arranged opposite the first wall.The second wall comprises an inner side facing the first wall and an outer side facing away from the first wall, wherein in particular the inner side of the second wall is spaced, at least in regions, from an inner side of the first wall, whereby a plenum is formed between the inner side of the first wall and the inner side of the second wall. The first wall is intended to be arranged facing away from the body of a user, while the second wall is intended to be arranged towards the body of a user. In this respect, the first wall can also be referred to as the distal wall of the plenum shell, and the second wall can be referred to as the proximal wall of the plenum shell. Thus, the first wall forms a distal side of the plenum shell and the second wall forms a proximal side of the plenum shell, wherein a circumferential edge extends between the distal side of the plenum shell and the proximal side of the plenum shell.In certain embodiments, a connecting seam between the first, distal, wall and the second, proximal, wall is formed at least partially along the circumferential edge or extends along at least a portion of the circumferential edge. In other embodiments, however, the entire plenum shell is manufactured seamlessly and in one piece using a suitable additive manufacturing process. A plurality of outflow channels are arranged in the second, proximal, wall, which extend between the inside of the second, proximal, wall and the outside of the second, proximal, wall and which have a cumulative outlet cross-sectional area that corresponds to the sum of the flow cross-sectional areas of all outflow channels. If the outflow channels or some of the outflow channels have non-constant cross-sections, this is the sum of the smallest flow cross-sectional areas of each outflow channel.The flow cross-sectional area is in particular measured perpendicular to the longitudinal axis of an outflow channel. The plurality of outflow channels comprises in particular at least 50 outflow channels, and in more specific embodiments at least 100 outflow channels. The ventilation device further comprises at least one fan, which opens on its pressure side into the plenum formed inside the plenum shell of the ventilation device. The plenum is in fluid communication with the outflow channels and is delimited on the pressure side of the fan by the outlet surface of the impeller of the fan. The outflow channels branch off in particular directly from the plenum. The plenum, or a volume of the plenum, thus comprises the entire free space within the plenum shell of the ventilation device downstream of the outlet surface of the impeller of the at least one fan.Furthermore, the plenum shell has at least one inlet opening, which is either in fluid communication with the suction side of at least one of the at least one fans, thus enabling a fan arranged within the interior of the plenum shell to draw in fluid from the environment and convey it into the plenum, or establishes a fluid connection between the plenum and the pressure side of a fan arranged outside the plenum shell, thus enabling a fan arranged outside the interior of the ventilation device to convey fluid into the plenum. It will be readily apparent to a person skilled in the art that the plenum openings adjoining the pressure side of the at least one fan are intended to supply fluid into the plenum and therefore represent inlet openings of the plenum. The fan is thus configured to convey fluid into the plenum and out of the plenum through the outflow channels.It is further provided that a ratio of the volume of the plenum to the cumulative outlet cross-sectional area of ​​the outlet channels is 0.75 m or more. As explained above, the volume of the plenum corresponds to the total free space within the interior of the ventilation device downstream of the pressure side of the at least one blower and is limited upstream by the pressure-side outlet surface of the impeller of the at least one blower or is measured up to the pressure-side outlet surface of the impeller of the at least one blower. In other words, the volume of the plenum corresponds to the volume of the interior of the plenum shell, defined by the first, distal, wall and the second, proximal, wall, downstream of the pressure-side outlet surface of the impeller of the at least one blower, which interior can be filled with and through which fluid can flow.

[0016] The aforementioned minimum ratio of the plenum volume to the cumulative outlet cross-sectional area ensures that a sufficiently low flow velocity is established within the plenum so that pressure differences within the plenum and adjacent to the outlet channels are minimized to such an extent that a pressure difference that is approximately the same is established across each of the outlet channels. This ensures that the mass flow through one of the outlet channels, in relation to the total mass flow through all outlet channels, is determined at least essentially only by its flow cross-sectional area in relation to the cumulative outlet cross-sectional area of ​​the outlet channels and does not depend on the position of the outlet channel in the second, proximal, wall.Furthermore, if the volume of the plenum is sufficiently large in relation to the cumulative outlet cross-sectional area of ​​the outlet channels, the outlet channels receive flow from a quasi-static fluid volume. Thus, at the inlet to the outlet channels, there is little or virtually no flow deflection from a directed flow in the plenum. This design inherently ensures uniform, homogeneous fluid states and flow conditions upstream of the individual outlet channels. As a result, the outlet channels receive at least a largely uniform flow. Therefore, in order to improve a uniform distribution of the fluid flow across the outlet channels and thus a uniform cooling effect, it is not necessary to make their diameter larger downstream of the fan or to arrange flow deflectors on the downstream sides of the outlet channels, as proposed in US 2019 / 0008219.The design of the geometric relationships according to the ventilation device proposed here, however, results overall in a uniform supply of the fluid conveyed by the fan to the outflow channels and a controlled flow to the outflow channels. This also results in excellent controllability of the distribution of the outflowing fluid and thus the ventilation and cooling effect across the surface of the second, proximal, wall, as well as efficient utilization of the blown-out fluid, which is essentially independent of the overall fluid mass flow.

[0017] This effect naturally increases the larger the ratio of plenum volume to the cumulative exit cross-sectional area of ​​the outflow ducts. Therefore, more specific embodiments can have a ratio of the plenum volume to the cumulative exit cross-sectional area of ​​the outflow ducts of 0.9 m² or more, 1.2 m² or more, 1.5 m² or more, 2.0 m² or more, 2.5 m² or more, or even 3.0 m² or more. In practice, the size of the ventilation device, for a given cumulative exit cross-sectional area of ​​the outflow ducts, represents an upper limiting factor, which in turn influences the overall achievable ventilation and thus cooling effect.

[0018] It goes without saying that the outflow of fluid from the plenum should occur at least substantially exclusively through the outflow openings in the second, proximal, wall, since the fluid flowing out through these outflow openings ultimately causes the cooling effect. Therefore, according to other aspects, the plenum shell is configured, for example, such that when the at least one inlet opening is closed or the at least one fan is in operation, at a certain pressure difference between the plenum and the environment, the mass flow through the second, proximal, wall is at least 75% or more of the total mass flow flowing out of the interior of the plenum shell or conveyed by the at least one fan. In exemplary embodiments, this value is 80% or more, 85% or more, 90% or more, 95% or more, or 99.5% or more.The reference cross-section for the pressure loss coefficient is the total area of ​​the respective region of the plenum shell. It can be provided that the plenum shell, apart from the outflow channels and the at least one inlet opening, is at least substantially impermeable to fluids or air. Thus, the at least one blower and the plenum are configured such that fluid conveyed into the plenum by the at least one blower can flow out of the plenum at least substantially exclusively and solely via the outflow channels in the second, proximal, wall, at least as long as the blower is in operation.

[0019] The fact that the proposed ventilation device is intended and configured to be worn under clothing implicitly results in a limitation on the thickness of the ventilation device, which would have to be measured above the first and second wall of the plenum shell so that the ventilation device does not protrude too much under clothing and / or the wearer is not unduly restricted in their mobility. A distance between the first wall of the plenum shell and the second wall of the plenum shell, or between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell, is 3 cm or less in certain embodiments, for example 2 cm or less, 1.5 cm or less, or 1 cm or less. This dimension defines, so to speak, a free height of the plenum upstream of or above the inlets of the outflow channels.In certain embodiments, the distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell in the area provided with outflow channels is 3 cm or less, for example 2 cm or less, 1.5 cm or less, or 1 cm or less. Depending on the application, embodiments can also be provided in which the distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell is up to a maximum of 5 cm or up to a maximum of 7 cm. Such high values ​​can be provided, for example, but not only, if the distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell is designed to be different locally.In this case of a non-constant distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell, these dimensions refer, for example, to a maximum distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell.

[0020] Accordingly, it can be said that in particular the ratio of the volume of the plenum to the cumulative exit cross-sectional area of ​​the outflow channels and further divided by the maximum distance between the inside of the first wall of the plenum shell and the inside of the second wall of the plenum shell is 10 or more, and in particular is 15 or more, 22 or more, 37 or more, or 75 or more.

[0021] In the event that the said walls of the plenum shell are elastic, these distances must be measured in particular when the pressure inside the plenum corresponds to at least the external pressure -0.0% of the external pressure and at most the external pressure +0.3% of the external pressure and the said walls of the plenum shell are not subjected to any external force.

[0022] The described ventilation device is designed on the outside of the second, proximal, wall in particular in such a way that the outflow from at least 80% of the outflow channels exits directly, freely and unhindered into the environment or, when used as intended, directly, freely and unhindered hits the skin or clothing of the wearer.

[0023] In the context of this description, “a” or “an” are to be understood as indefinite articles and not as numerals, unless another meaning is explicitly indicated, for example by the use of “exactly one” or “exactly one”.

[0024] According to further aspects, the at least one fan is a radial fan. The impeller of the at least one fan has a circumferential surface area on its outer circumference, wherein the ratio of the cumulative circumferential surface area of ​​the at least one fan divided by the cumulative outlet cross-sectional area of ​​the outlet channels is 2.4 or more. The cumulative circumferential surface area represents the sum of the circumferential surface areas of the impellers of all fans. This value, in a sense, relates the dynamic pressure at the impeller outlet to the dynamic pressure in the outlet channels. In this regard, too, the person skilled in the art will readily recognize that the flow to the outlet channels can be made more uniform the greater the ratio of the cumulative circumferential surface area of ​​the at least one fan divided by the cumulative outlet cross-sectional area of ​​the outlet channels.In more specific embodiments, the ratio of the cumulative circumferential surface area of ​​the at least one fan divided by the cumulative outlet cross-sectional area of ​​the outlet channels is 3.0 or more, 5.0 or more, or 10.0 or more. According to further aspects, the hydraulic diameter of at least 80% of the outlet channels is less than or equal to 50% of the length of the respective outlet channel. This ensures a directed outflow of the fluid from the outlet channels that meet this condition, making it possible to direct the fluid jet thus generated onto the wearer's skin in a targeted manner. In the context of the present document, this wording expressly also includes the case in which a garment, for example a sweat-absorbing or sweat-transporting garment, is worn between the ventilation device and the skin.In this case too, for the sake of simplicity, it is stated that the fluid jet is directed onto the wearer's skin. The cooling effect on the skin through the evaporation of sweat is in this case essentially identical to the cooling effect when the sweat evaporates directly on the skin. The described ventilation device is designed on the outside of the second, proximal, wall in particular such that the outflow from at least 80% of these at least 80% of the outflow channels, whose hydraulic diameter is less than or equal to 50% of the length of the respective outflow channel, escapes directly, freely and unhindered into the environment or, when used as intended, strikes the skin or clothing of the wearer directly, freely and unhindered.In more specific embodiments, it can be provided that the outflow from at least substantially all of these at least 80% of the outflow channels, whose hydraulic diameter is less than or equal to 50% of the length of the respective outflow channel, exits directly, freely and unhindered into the environment or, when used as intended, directly, freely and unhindered onto the skin or clothing of the wearer. With sufficient speed, this jet penetrates from a certain distance to the skin of the wearer or a piece of clothing worn between the ventilation device and the skin, penetrates fluid boundary layers, displaces moisture-enriched fluid, and thus particularly efficiently promotes the evaporation of sweat. If the cross-section of the outflow channels varies over their length, the smallest hydraulic diameter of the individual outflow channels is decisive, i.e.The smallest hydraulic diameter of each of at least 80% of the outflow channels is less than or equal to 50% of the length of the respective outflow channel. The hydraulic diameter is calculated as four times the cross-sectional area divided by the circumference of an outflow channel.

[0025] It can further be provided that at least one spacer element is arranged on the outer side of the second, proximal, wall, which spacer element has a vertical extension from the outer side of the second, proximal, wall. The spacer element makes it possible to ensure a distance between the outer side of the second, proximal, wall and an opposing object, for example, from the wearer's body, defined within comparatively narrow limits, such that the distance at which an air jet emerging from an outlet opening impinges on the wearer's skin is defined within comparatively narrow limits, while at the same time a minimum space is maintained through which the heated and / or moisture-enriched air can flow out again. For example, the at least one spacer element can be a plurality of mushroom-shaped spacer elements extending from the outer side of the second, proximal, wall.In another example, the at least one spacer element is provided by a spacer fabric arranged on or above the outer side of the second, proximal, wall. Spacer fabrics can be described, for example, as double-face textiles in which the warp-knitted fabric surfaces are kept apart by spacer-maintaining connecting threads, so-called pile threads. The vertical extent of the at least one spacer element results in this case from the thickness of the spacer fabric. The spacer fabric can, in particular, be designed and arranged such that the openings of the outflow channels on the outer side of the second, proximal, wall are not covered. Of course, the examples mentioned are not to be understood as exhaustive.The at least one spacer element can, in particular, be arranged such that the entire surface of the outer side of the second, proximal, wall is kept at a distance from an opposite support surface. For this purpose, for example, a plurality of individual spacer elements can be arranged, or a spacer fabric can cover the entire outer side of the second, proximal, wall. However, it is crucial that the at least one spacer element impedes the flow of fluid parallel to the outer side of the second, proximal, wall in a space formed between the outer side of the second, proximal, wall and an opposite support surface on which the at least one spacer element rests, as little as possible, in order to enable the outflow of moisture-enriched and / or heated air between the plenum shell and the wearer's body.

[0026] In exemplary embodiments, at least one fan of the at least one fan is arranged inside the plenum shell and is in fluid communication on the suction side with at least one of the at least one inlet opening. In particular, it can be provided that all fans are arranged inside the plenum shell and are in fluid communication on their suction side with at least one of the at least one inlet opening. This design with a fan integrated inside the plenum shell results in a compact and easy-to-handle device. An inlet opening, i.e. at least one of the at least one inlet opening, can in particular be arranged or formed on a circumferential edge of the plenum shell. This edge can in particular be arranged between the first wall and the second wall. This embodiment can prove advantageous since the first, distal, wall is intended to be covered by clothing.Protective clothing, in particular, is usually heavy and dense, so that the intake of ambient air through the clothing resting on or tightly fitting the first, distal, wall is either impossible or only possible with significant pressure losses. The second, proximal, wall, on the other hand, is designed to be positioned adjacent to the body, which would draw in already warmed and / or moisture-enriched air at this point. Placing an inlet opening on the second, proximal, wall would impair the effectiveness and efficiency of the desired cooling for the wearer's body.

[0027] In this context, it can further be provided that in the region of the at least one inlet opening, a flow-preventing element extends in the circumferential direction of the plenum shell, wherein the flow-preventing element has a height extension measured from the outside of the second wall, and wherein the flow-preventing element covers at least the at least one inlet opening in the circumferential direction. The flow-preventing element is therefore an element, in particular a plate-like element, which has a height extension and an extension in the circumferential direction of the plenum shell. The circumferential direction is defined in particular along the circumference of the first wall and / or the second wall. The height extension extends over the outside of the second, proximal, wall. That is, the flow-preventing element extends with its vertical extent to the side of the plenum shell on which the second wall is arranged, or, with regard to the intended use, proximally, i.e. towards the body of the wearer. The flow-preventing element has a pressure loss coefficient of at least 100 for an inflow onto its surface, wherein the pressure loss coefficient in more specific embodiments is 1000 or more, or 2500 or more, or 10000 or more. The reference cross-section for the pressure loss coefficient is the surface of the flow-preventing element, formed from the vertical extent and the extent in the circumferential direction of the plenum shell. In more specific embodiments, the flow-preventing element is at least substantially fluid-impermeable or air-impermeable.In other aspects, this can be provided for at least all of the inlet openings of the at least one inlet opening that are arranged or formed in the edge. It can further be provided that the flow-preventing element extends laterally of the respective inlet opening by at least 50%, in more specific cases at least 100% of the circumferential extent of the respective inlet opening on each side of the inlet opening in the circumferential direction. It can be provided that the vertical extent of said flow-preventing element from the outside of the second, proximal, wall at least substantially corresponds to the height of the above-mentioned at least one spacer element, or has a height that corresponds to 80-100% of the height of the at least one spacer element.The flow-preventing element effectively prevents already heated and / or moisture-enriched air from the area between the second, proximal, wall and the wearer's body from being sucked in again by a fan, as this would significantly impair the cooling efficiency.

[0028] Furthermore, it can be provided that a plurality of flow-preventing elements extend along the circumference of the plenum shell in the circumferential direction of the plenum shell. The flow-preventing elements have a vertical extension measured from the outside of the second wall, with an outflow passage being formed between each two flow-preventing elements. The vertical extension extends over the outside of the second, proximal, wall. This means that the flow-preventing elements extend with their vertical extension to the side of the plenum shell on which the second wall is arranged, or, with regard to the intended use, proximally, i.e. towards the body of the wearer. When the presently described subject matter is used as intended, an outlet plenum is formed between the second, proximal, wall, the body of the wearer, and the segmented wall.When the ventilation device is used as intended, fluid can flow out of the outlet area or the outlet plenum through the outflow passages if the outlet area is blocked or restricted by a closed surface, such as the wearer's body, relative to the outside of the second, proximal, wall. The total flow-through cross-sectional area of ​​the outflow passages enclosed between the flow-restricting elements is at least 10 times the cumulative exit cross-sectional area of ​​the outflow channels. Due to the presence of the flow-restricting elements, the flow within the outlet plenum formed in this way during intended use can be calmed such that fluid flowing out of the outlet channels can escape laterally to a lesser extent and thus strikes the opposite skin and flows away along the skin.On the other hand, the size of the cumulative minimum cross-sectional area of ​​the outflow passages ensures that no significant backpressure builds up within the outlet plenum formed during intended use, which counteracts the formation of fluid jets flowing out of the outflow channels. The outflow passages can be arranged so that, when the ventilation device is used as intended, they allow the used fluid to flow out where it can be expected that it can flow out as unhindered as possible under clothing. On the other hand, the outflowing air can be channeled in such a way that it flows over certain parts of the body located next to the actual ventilation device, also causing evaporation-induced cooling there, albeit to a lesser extent.According to further aspects, the outflow passages can be arranged such that the resulting crossflow during operation disrupts the fluid jets flowing out of the outflow channels as little as possible. It can be provided that the flow-hindering elements mentioned here also have, for example, a height extension above the outer side of the second, proximal, wall that at least substantially corresponds to the height of the above-mentioned at least one spacer element, or has a height that corresponds to 80-100% of the height of the at least one spacer element.

[0029] The flow-preventing elements can, for example, be formed as integral parts of the plenum shell or a component of the plenum shell. In other embodiments, particularly when the at least one spacer element on the outer side of the second, proximal, wall is a spacer fabric, the flow-preventing elements can be formed by appropriately suitable peripheral areas, for example, coated with neoprene, on the periphery of the spacer fabric.

[0030] According to further aspects, it can be provided that a diffuser is arranged on the pressure side of at least one of the at least one blowers, the flow cross-section of which continuously expands from the outlet of the impeller of the blower and opens into a chamber of the plenum with a discontinuous cross-sectional transition. In further exemplary embodiments, the plenum, downstream of any outlet diffuser for the outflow from the at least one blower, is designed without flow-guiding elements and in particular without subdivision. This means that it can be provided that a chamber of the plenum, downstream of any outlet diffuser for the outflow from the at least one blower, is a single, continuous and undivided cavity. This is also suitable for ensuring inherently uniform, homogeneous fluid states and flow conditions upstream of the individual outflow channels.In this context, it should be emphasized that the interior of an above-mentioned diffuser is part of the plenum, while a part of the interior space in which the at least one fan is arranged in embodiments, or space in the interior space which serves in embodiments to accommodate energy storage devices, controls and the like, is by definition not part of the plenum.

[0031] In exemplary embodiments, the ventilation device is designed to be worn on the upper body, on the chest or on the back. The plenum shell has a top side and a bottom side, with the top side facing the cranial arrangement, toward the neck, and the bottom side facing the caudal arrangement, toward the legs. The first, distal, wall and the second, proximal, wall on a top side of the ventilation device are configured to taper toward an upper end of the ventilation device, for example, in a trapezoidal shape. In more specific embodiments, the at least one inlet opening is arranged on the bottom side of the plenum shell.

[0032] Furthermore, a protective garment is disclosed in which a ventilation device of the type described above is integrated, wherein the second, proximal, wall is arranged as the inner side of the protective garment. In particular, the protective garment can be a bulletproof vest.

[0033] According to further aspects, the teaching described here can also be implemented by a method for creating an air flow on body parts. The method comprises arranging a plenum shell, which encloses a plenum and has a perforated plate, over a body part. The plenum shell is arranged such that the perforated plate is arranged towards the corresponding body part. In particular, the perforated plate is arranged at a defined desired distance from the body part. Air, in particular ambient air, is introduced into the plenum by means of at least one blower. This air is directed from the plenum to the skin of the body part via openings in the perforated plate. In particular, it can be provided that the escaping air from at least 80% of the openings in the perforated plate is directed directly, freely and unhindered onto the skin of the body part.In more specific embodiments of the described method, it can be provided that the escaping air from at least substantially all openings of the perforated plate is directed directly, freely, and unhindered onto the skin of the body part. The blower is operated such that the static pressure reduction across the openings of the perforated plate is at least 25% of the static pressure buildup across the impeller of the at least one blower. This operating parameter ensures uniform air flow to the openings of the perforated plate. The advantages of uniform air flow and the resulting cooling effect for the body part exposed to the air flow are discussed in detail above.

[0034] According to other aspects, the at least one fan is operated such that a turbulent flow is present at the outlet from at least 80% of the openings of the perforated plate. This promotes the formation of highly concentrated and directed air jets upon exiting the openings, which supports the efficient use of air in the manner described above, similar to impingement cooling. The method is carried out, for example, but not necessarily, by means of a ventilation device or a protective garment of the type described above, wherein the perforated plate is the second, proximal, wall of the plenum shell and the openings of the perforated plate are the outflow channels.

[0035] The specific embodiments mentioned above can be combined with one another. Further, non-specifically disclosed embodiments of the teachings of this document will be readily apparent to those skilled in the art. BRIEF DESCRIPTION OF THE FIGURES

[0036] The facts presented here are explained in more detail below using selected exemplary embodiments shown in the drawings.

[0037] Fig. 1 is a view of a first exemplary embodiment of a

[0038] Ventilation device of the type described above;

[0039] Fig. 2 shows a section through the plenum shell of the ventilation device from Figure 1;

[0040] Fig. 3 is a perspective view of the ventilation device from

[0041] Figure 1 looking towards the second, proximal, wall of the plenum shell;

[0042] Fig. 4 is a longitudinal section through the ventilation device of Figure 1;

[0043] Fig. 5 is an exploded view of a plenum shell of a second exemplary embodiment of a ventilation device of the type described above; and

[0044] Fig. 6 shows a case in which the plenum envelope of Figure 5 can be received to form a ventilation device of the type described above.

[0045] The drawings are partially highly schematic. Details not necessary for understanding the described subject matter have been omitted. Furthermore, the drawings show only selected embodiments and may not be used to limit the subject matter described in the claims. Embodiments of the claimed invention not shown are covered by the claims. EXEMPLARY EMBODIMENTS

[0046] Figure 1 shows a view of an exemplary embodiment of the ventilation device 1 described here, with a perspective view of the first, distal, wall 11. A second, proximal, wall 12, not visible in the present illustration, is arranged opposite the first, distal, wall 11. The first, distal, wall 11 and the second, proximal, wall 12 are connected to one another. In this case, "connected" is to be understood to mean that the two structural elements in which the two walls are formed are structurally fixed relative to one another and not in such a way that they necessarily have to touch one another directly, although this is of course by no means excluded and is certainly an extremely practical embodiment. One or more elements arranged between the two structural elements mentioned may also certainly be present.Likewise, the entire plenum shell 10 could be manufactured seamlessly and in one piece using a suitable additive manufacturing process. Thus, the first, distal, wall 11 and the second, proximal, wall 12 form a plenum shell 10. This implicitly results in an inner side of the second, proximal, wall facing the first, distal, wall and an inner side of the first, distal, wall facing the second, proximal, wall being spaced apart from one another at least in some areas, such that an interior space is formed within the plenum shell 10, which comprises a plenum, as can be seen below. In the present exemplary embodiment, the ventilation device is intended to be worn under clothing on the upper body. According to the intended purpose, the second, proximal, wall 12 is arranged proximally, i.e., facing toward the body, and the first, distal, wall 11 is arranged distally, i.e., facing away from the body.The plenum shell 10 has an upper side 20, which is intended for cranial placement, i.e., toward the neck, and a lower side 30, which is intended for caudal placement, i.e., toward the legs. The upper part of the plenum shell tapers towards the upper side 20 in an anatomically advantageous manner, so that it can be worn comfortably at this point, for example, between the shoulders, while restricting freedom of movement as little as possible. Adjacent to the lower side 30 of the plenum shell 10, a chamber 101 for a blower is provided within the plenum shell 10. The blower chamber 101 is arranged in a raised manner on the outer side of the first, distal, wall 11, since on this side of the plenum shell 10, which is intended for placement distal to the body, elevations on the outer side of the plenum shell do not result in any loss of comfort in the form of pressure points or the like. The first, distal, wall is stiffened in the area of ​​the blower chamber 101 by struts 102.The blower chamber further comprises a cover 103 that closes a mounting opening of the blower chamber 101. A blower, in particular a radial blower, can be mounted within the blower chamber 101 and removed therefrom through the mounting opening closed by the cover 103. Furthermore, an inlet opening 14 is arranged in a peripheral edge 13 of the plenum shell 10 in the region of the blower chamber 101. A blower arranged within the blower chamber 101 can draw in fluid, in particular air, through the inlet opening 14 and convey it, in the manner described below, into a plenum formed within the plenum shell 10. From there, it is guided to the wearer's body through outflow channels in the second, proximal, wall, in a manner also described in more detail below.

[0047] Figure 2 shows a section through the plenum shell 10 shown in Figure 1, with a view of the inside of the second, proximal, wall 12. The peripheral edge 13 is shown in section. A plenum 15 is formed within the plenum shell. In the present exemplary embodiment, a diffusion path 104 extends from the blower chamber 101, with a cross-sectional area that continuously expands away from the blower chamber 101 and ends at a shock diffuser 105. A radial fan 109 arranged within the blower chamber can draw fluid through the inlet opening 14 and convey it into the plenum 15. In this context, the plenum is defined as the entire free space within the plenum shell when the fan is installed, and the upstream boundary of the plenum is limited by the outlet surface of the fan impeller on the pressure side of the fan when the fan is installed.As can be seen, the plenum 15 downstream of the diffusion section 104 is designed without flow-guiding elements and without subdivisions. The second, proximal, wall 12 comprises a plurality of outflow channels 121 extending from the inner side of the second, proximal, wall 12, which is arranged facing the first, distal, wall 11, and the outer side of the second, proximal, wall 12, which is arranged facing away from the first, distal, wall 11.Fluid conveyed into the plenum 15 by the fan 109 can flow out of the plenum 15 through the outflow channels 121. When the ventilation device is positioned correctly on the wearer's body, it impinges on the wearer's skin or a layer of clothing worn on the skin that wicks away and / or absorbs sweat. There, it contributes to the evaporation of sweat and, depending on temperature conditions, also to the conductive heat absorption, thus cooling the wearer's body. In the presently illustrated embodiment, the outflow channels 121 are evenly distributed over the surface of the second, proximal, wall, although this is not necessarily the case.If necessary, the outflow channels 121 can be arranged more densely and / or have a larger diameter, for example at locations intended for placement over a body part where increased sweat production is expected, than at other locations on the second, proximal, wall 12. Furthermore, raised spacer elements 122 are arranged on the inside of the second, proximal, wall 12. These prevent the plenum 15 from being compressed by external forces. This also makes it possible to manufacture the first, distal, wall 11 and the second, proximal, wall 12 from comparatively soft materials, which further improves wearing comfort. As can be seen, the spacer elements 122 are the only elements arranged within the plenum 15 and do not fulfill a flow-conducting function.

[0048] Figure 3 shows a view of the embodiment of the presently described ventilation device 1 illustrated by way of example in Figures 1 and 2, with a perspective view of the outside of the second, proximal, wall 12. The outflow channels 121 open on the outside of the second, proximal, wall 12. A plurality of spacer elements 123 are also arranged on the outside of the second, proximal, wall 12. These ensure that a minimum distance is always maintained between the outside of the second, proximal, wall 12 and an object opposite which the ventilation device 1 with the outside of the second, proximal, wall 12 is arranged, for example, the wearer's body, so that a minimum space is maintained between such an object and the outside of the second, proximal, wall 12, through which the heated and / or moisture-enriched air can flow out.The spacer elements 123 are mushroom-shaped pins whose rounded and widened heads are arranged above the outer side of the second, proximal, wall 12 and are intended to rest on the wearer's body or a layer of clothing. The widened and rounded shape, which is also visible in connection with Figure 4, also improves wearing comfort. In the area of ​​the inlet opening 14, a flow-preventing element 108 extends from the outer side of the second, proximal, wall 12, has a vertical extension above the outer side of the second, proximal, wall, and circumferentially covers at least the inlet opening 14. In the presently illustrated embodiment, the underside of the blower chamber 101 forms part of this flow-preventing element.In the present embodiment, the flow-restricting element 108 extends over the entire underside 30 of the ventilation device and also extends a short distance laterally. This prevents air used during operation, which has already been blown out through the outflow channels 121, from being sucked in through the inlet opening 14 and thus recirculated, which would obviously significantly impair cooling efficiency. Furthermore, a plurality of flow-restricting elements 107 extend along the circumference of the plenum shell 10, with the individual flow-restricting elements 107 spaced apart from one another in the circumferential direction such that an outflow passage is formed between each two flow-restricting elements 107.The total flow-through cross-sectional area of ​​the outflow passages enclosed between all flow-restricting elements 107, 108 is at least 10 times the cumulative exit cross-sectional area of ​​the outflow channels 121 in the second, proximal, wall 12. This ensures that no significant counterpressure builds up when flowing through the outflow passages, which in turn would reduce the momentum and thus the effectiveness of the air flowing out of the outflow channels 121. Furthermore, due to the presence of the flow-restricting elements 107 and 108, the flow within the outlet plenum formed in this way during intended use can be calmed, such that fluid flowing out of the outlet channels can escape laterally to a lesser extent and thus strikes the opposite skin and flows along the skin.

[0049] Figure 4 illustrates a cross-section through a portion of the ventilation device 1 with a sectional plane perpendicular to the first, distal, wall 11 and the second, proximal, wall 12. It can be seen how the spacer elements 122 extend between the inner sides of the first, distal, wall 11 and the second, proximal, wall 12, thus supporting the first, distal, wall 11 and the second, proximal, wall 12 against each other. The plenum 15 is formed between the first, distal, wall 11 and the second, proximal, wall 12. The outflow channels 121 extend through the second, proximal, wall 12. These are depicted here as cylindrical bores, but can also have other geometries. It is advantageous if the smallest hydraulic diameter of an outflow channel is 50% or less of the length of the outflow channel. This promotes the formation of a directed fluid jet at the outlet from the outflow channel 121.Furthermore, it is crucial for the subject matter described here, regardless of the exemplary embodiment shown, that the ratio of the volume of the plenum 15, i.e., the total free space within the plenum shell 10 downstream of the pressure-side outlet surface of the impeller of the fan 109, to the cumulative outlet cross-sectional area of ​​the outlet channels of the second, proximal, wall 12 has a value of at least 0.75 m. Due to the fact that the volume is selected to be correspondingly large in relation to the cumulative outlet cross-sectional area of ​​the outlet channels of the second, proximal, wall 12, a virtually static fluid volume with a negligible or only very small flow velocity through the plenum is established within the plenum 15. As a result, the pressure differences within the plenum 15 are at least substantially negligible, so that each of the outlet channels 121 at its inlet, i.e., on the inside of the second, proximal, wall 12, is subjected to almost the same pressure. As a result of this, and because each of the outflow channels 121 is supplied with fluid from a virtually static volume, it follows that the mass flow through an outflow channel 121, for a given pressure in the plenum 15 and a given external pressure, depends essentially exclusively on its smallest flow cross-section and is essentially independent of the position of the outflow channel 121 on the second, proximal, wall 12. Also visible are flow-restricting elements 107, which have a vertical extension H above the outside of the second, proximal wall and a circumferential extension U. In particular, the circumferential extension of different flow-restricting elements 107 can be different.

[0050] In connection with Figures 5 and 6, a further exemplary embodiment of the described ventilation device will now be explained.

[0051] Figure 5 shows an exemplary embodiment of the plenum shell 10 of a ventilation device of the type described here in an exploded view. The plenum shell comprises two halves 16 and 17, wherein the first, distal, wall 11 is formed on the first half 16 and the second, proximal, wall 12 with the outflow channels 121 is formed in the second half 17. Furthermore, a chamber 101 for the fan 109 is formed in the first half 16 of the plenum shell. The fan 109 can be inserted into the chamber 101 and removed again through an opening 101a of the chamber 101 on the top side of the first half 16 of the plenum shell. In this way, the fan 109 can be replaced even when the two halves 16 and 17 are assembled to form a plenum shell for the ventilation device, as explained below. A cover 103 is provided to close the opening 101a.The cover 103 is secured to the first half 16 of the plenum shell by means of known detachable locking elements. The fan chamber 101 is secured on its underside by the

[0052] The chamber floor 101b is closed, which is integrated into the second half 17 of the plenum shell. The two halves 16 and 17 can be joined along their edges 13a and 13b, for example by gluing or welding, thereby forming a plenum shell that encloses the plenum 15. In this embodiment, too, the plenum 15 is designed without flow-guiding elements and without subdivisions downstream of a diffusion section arranged in a case-by-case manner for the outflow from the fan 109. Before joining the halves 16 and 17, a correspondingly cut inner spacer fabric 18 is inserted between the two halves in such a way that it lies within the plenum after joining. The inner spacer fabric 18 supports the first, distal, wall 11 and the second, proximal, wall 12 against each other in such a way that compression of the plenum 15 by external forces acting on the walls is avoided or at least greatly limited.The inner spacer fabric 18 is thus analogous to the spacer elements shown in Figure 2 and likewise does not fulfill a flow directing function, but rather an exclusive distance maintaining function between the first, distal wall and the second, proximal wall. The inner spacer fabric 18 is perforated in such a way that the outflow channels 121 are not covered. Furthermore, the thread density within the spacer fabric is comparatively low, such that the volume of the plenum 15, i.e. the fluid volume contained within the plenum 15, is not significantly reduced by the inner spacer fabric 18, and furthermore such that large flow cross-sections are also present within the spacer fabric. Thus, the inner spacer fabric 18, particularly in combination with the low flow velocity within the plenum 15 as described, does not cause any significant pressure loss within the plenum. The plenum shell, orthe halves 16 and 17 are dimensioned such that here too, the ratio of the volume of the plenum 15, i.e., the total free space within the plenum shell downstream of the pressure-side outlet surface of the impeller of the blower 109, to the sum of the cumulative outlet cross-sectional area of ​​the outlet channels 121 of the second, proximal, wall 12 has a value of at least 0.75 m. This ratio, in turn, results in the flow velocity in the plenum being very low, so that, in combination with the low thread density of the inner spacer fabric 18, the occurrence of pressure losses when flowing through the inner spacer fabric is at least substantially avoided.As explained above, this ratio of plenum volume to the cumulative outlet cross-sectional area of ​​the outlet channels results in all outlet channels being subjected to the same pressure, or at least with negligible pressure differences, and from a nearly static volume. The resulting advantages are described above.

[0053] To complete the ventilation device according to the embodiment explained in Figures 5 and 6, a sheath 2 of the type shown as an example in Figure 6 is also provided. The sheath 2 comprises, for example, a textile surface 21 and an outer spacer fabric 22, which are sewn, glued, welded, or connected together in another suitable manner along an edge 23 on the circumference of the sheath 2. The sheath is open on a peripheral side 28 such that the plenum sheath explained in connection with Figure 5, which is composed of the two halves 16 and 17, can be inserted into a pocket 24 formed between the textile surface 21 and the outer spacer fabric 22. The sheath is dimensioned such that the plenum sheath 10 explained in connection with Figure 5, which encloses a plenum, is tightly received within the pocket 24.There are no special requirements for the textile surface 21; of course, the material used should be sufficiently robust. Instead of the textile surface 21, a surface made of a suitable non-textile material could also be used. Adjacent to the open area.

[0054] On the peripheral side 28, tabs 25 and 26 are formed on the textile surface 21. The tabs 25 and 26 can be releasably attached to the outside of the outer spacer fabric 22 by means of hook-and-loop fasteners, snap fasteners, or other suitable means. These allow, when the plenum cover 10 is inserted into the pocket 24, to fix the plenum cover within the pocket 24, but also to remove the plenum cover from the pocket 24 after it has been detached from the outer spacer fabric 22.

[0055] The knitted spacer fabric 22 extends to the edge 23 such that the porosities of the knitted spacer fabric are open at the edge 23. Various peripheral regions are arranged on the circumference of the casing 2, in which the edge 23 is closed or covered with a material layer 27 with increased flow resistance, at least compared to the outer knitted spacer fabric 22. Analogous to the statements made above with regard to the flow-hindering elements, the material layers 27 have a pressure loss coefficient of at least 100, wherein the pressure loss coefficient in more specific embodiments is 1000 or more, or 2500 or more, or 10000 or more. The reference cross-section for the pressure loss coefficient is the area of ​​the outer knitted spacer fabric covered by the respective material layer. In more specific embodiments, the material layers 27 are at least substantially fluid-impermeable or air-impermeable.The material layers 27 extend over the edge area of ​​the outer spacer fabric 22 and, in the respective peripheral areas, cover and seal the open porosity of the outer spacer fabric 22 at the edge 23. The material layers 27 with increased flow resistance enclose gaps 29 between them in the circumferential direction, in which the porosity of the outer spacer fabric 22 is open in the edge area. The material layers 27 can be realized, for example, by coating them with neoprene.

[0056] It is now provided that the plenum cover explained in connection with Figure 5 is inserted into the pocket 24 such that the textile surface 21 lies on the outside of the first, distal, wall, while the outer spacer fabric 22 lies on the outside of the second, proximal wall. It can be provided that interacting hook-and-loop fastener elements are arranged on the inside of the textile surface 21 and on the outside of the first, distal, wall 11, by means of which the plenum cover 10 can be fixed within the pocket 24. Knobs can be arranged on the outside of the second, proximal, wall, which fix the outer spacer fabric 22 in a direction parallel to the outside of the second, proximal, wall and relative to the second, proximal, wall 12 of the plenum cover 10.It can also be provided that the outer spacer fabric 22 is perforated with an arrangement of perforation openings that corresponds to the arrangement of the openings of the outflow channels 121 on the outside of the second, proximal, wall 12 of the plenum sleeve 10. Thus, the plenum sleeve 10 can be arranged within the pocket 24 such that each outflow channel 121, or, in other embodiments, at least 80% of the outflow channels 121, opens into a perforation opening of the outer spacer fabric 22. The outflow from at least 80% of the outflow channels or from each outflow channel 121 thus exits directly, freely, and unhindered into the environment or, when used as intended, directly, freely, and unhindered onto the skin or clothing of the wearer. The inlet opening 14 of the plenum shell is located in the open peripheral side 28 of the casing 2.The resulting article represents a ventilation device in which the outer spacer fabric 22 functions as a spacer element 123, which has a vertical extension above the outer side of the second, proximal, wall 12 and thus ensures that a minimum distance is always maintained between the outer side of the second, proximal, wall 12 and a surface opposite it, through which air flowing out through the outflow channels 121 on the outer side of the second, proximal, wall 12 can flow out. This outflow occurs through the porosity of the outer spacer fabric 22. The air flows out of the outer spacer fabric 22 through the gaps 29 between the material layers 107 at the edge 23 into the environment.It is readily apparent to a person skilled in the art that a material layer 27 with increased flow resistance in this case represents a flow-preventing element 107 which extends in the circumferential direction of the plenum shell and has a height extension measured from the outside of the second, proximal wall.

[0057] According to a method described here, by means of which the teaching described here can also be implemented, a plenum shell enclosing a plenum and having a perforated plate is arranged above the skin of a body part to be cooled, with the perforated plate facing the body part to be cooled. By means of at least one fan, air is introduced into the plenum, and the air is directed from the plenum to the skin of the body part to be cooled via openings in the perforated plate. This promotes, among other things, the evaporation of sweat and the removal of moisture-enriched air above the skin, resulting in the desired cooling. The fan is operated in such a way that the static pressure reduction via the openings in the perforated plate is at least 25% of the static pressure buildup via the impeller of the at least one fan.This also ensures that all openings in the perforated plate receive air at essentially the same pressure and from a nearly static volume. The technical effects and associated advantages achieved in this way are explained in detail above. In a further development of this method, the fan is operated in such a way that turbulent flow is present at the outlet from at least 80% of the openings in the perforated plate. This ensures that directed jets emerge from the openings in the perforated plate, which, with their momentum, break through boundary layers on the opposite surface - this can be, in particular, the skin of a body part to be cooled or a sweat-absorbing or sweat-transporting garment worn against the skin - thereby significantly increasing the effect of the air flow directed onto the skin or garment.This process can optionally be carried out by means of a ventilation device of the type described above.

[0058] Although the subject matter of the present description has been explained using selected exemplary embodiments, these are not intended to limit the claimed invention. The claims encompass embodiments not explicitly shown, and embodiments of the presently claimed invention, as described in the claims, that differ from the examples shown are nevertheless covered by the claims.

Claims

PATENT CLAIMS 1. A ventilation device (1) for creating an air flow on body parts, which is intended and configured to be worn under clothing, wherein the ventilation device comprises a plenum shell (10), which in turn comprises a first wall (11) and a second wall (12), wherein the second wall is arranged opposite the first wall, wherein the second wall comprises an inner side facing the first wall and an outer side facing away from the first wall, and wherein a plurality of outflow channels (121) are arranged in the second wall, which extend between the inner side of the second wall and the outer side of the second wall and which have a cumulative outlet cross-sectional area corresponding to the sum of the smallest flow cross-sectional areas of each outflow channel, and wherein the ventilation device further comprises at least one fan (109) and the plenum shell has at least one inlet opening (14).which is in fluid communication with at least one of the at least one blower, and which blower opens into a plenum (15) on its pressure side, which plenum is formed in the plenum shell of the ventilation device, wherein the plenum (15) is in fluid communication with the outlet channels (121) and is delimited on the pressure side of the at least one blower by the outlet surface of the impeller of the at least one blower, whereby the at least one blower (109) is configured to convey fluid into the plenum (15) and through the outlet channels (121) out of the plenum, wherein a ratio of the volume of the plenum to the cumulative outlet cross-sectional area of the outlet channels is 0.75 m or more.

2. Ventilation device according to claim 1, wherein the at least one fan (109) is a radial fan and the impeller of the at least one fan has a circumferential surface on its outer circumference, wherein the ratio of the cumulative circumferential surface areas of the at least one fan divided by the cumulative flow cross-sectional area of the Exit channels are 2.4 or more.

3. Ventilation device according to one of the preceding claims, wherein the hydraulic diameter of at least 80% of the outflow channels (121) is less than or equal to 50% of the length of the respective outlet channel.

4. Ventilation device according to one of the preceding claims, wherein on the outside of the second wall (12) at least one spacer element (123) is arranged, which has a height extension (H) from the outside of the second wall.

5. Ventilation device according to one of the preceding claims, wherein at least one fan of the at least one fan (109) is arranged in the interior of the plenum shell and is in fluid communication on the suction side with at least one of the at least one inlet opening (14).

6. Ventilation device according to the preceding claim, wherein at least one of the at least one inlet opening (14) is arranged on a peripheral edge (13) of the plenum shell (10).

7. Ventilation device according to one of the two preceding claims, wherein in the region of the at least one inlet opening (14) a flow-preventing element (108) extends in the circumferential direction of the plenum shell (10), wherein the flow-preventing element has a height extension (h) measured from the outside of the second wall, and wherein the flow-preventing element covers at least the at least one inlet opening in the circumferential direction.

8. Ventilation device according to claim 7 as dependent on claim 4, wherein the height extension (h) of the flow-preventing elements is substantially equal to the height extension (H) of the at least one spacer element (123).

9. Ventilation device according to one of the preceding claims, wherein a diffuser (104) is arranged on the pressure side of at least one of the at least one blower, the flow cross-section of which expands continuously from the outlet from the impeller of the blower and which opens into a chamber of the plenum (15) with a discontinuous cross-sectional transition (105).

10. Ventilation device according to one of the preceding claims, wherein the ventilation device is intended to be worn on the upper body on the chest or on the back, wherein the plenum envelope (10) has a top side (20) and a bottom side (30), wherein the first wall and the second wall at the top side of the ventilation device taper towards an upper end of the ventilation device.

11. Protective clothing, in particular a bulletproof vest, wherein a ventilation device according to one of the preceding claims is integrated into the protective clothing and the second wall (12) is arranged as the inside of the protective clothing.

12. A method for creating an air flow on body parts, comprising arranging a plenum shell which encloses a plenum and has a perforated plate above the skin of a body part, wherein the plenum shell is arranged such that the perforated plate is arranged towards the body part, arranging the perforated plate at a distance from the body part and introducing air into the plenum by means of at least one blower and directing the air from the plenum to the skin of the body part via openings in the perforated plate, wherein the at least one blower is operated such that the static pressure reduction via the openings in the perforated plate is at least 25% of the static pressure buildup via the impeller of the at least one blower.

13. Method according to the preceding claim, wherein the at least one blower is operated in such a way that at least 80% of the There is turbulent flow through the openings of the perforated plate.

14. Method according to the preceding claim, wherein the method is carried out by means of a ventilation device (1) according to one of claims 1 to 10 or a protective garment according to claim 11, wherein the perforated plate is the second wall (12) of the plenum shell (10) and the openings of the perforated plate are the outflow channels (121).

Images