HOT AIR DEVICE

Description

TECHNICAL AREA

[0001] The invention relates to the technical field of hot air devices, in particular to occupational safety when working with a hot air device. The invention specifically relates to a combination of a heating tube and a protective tube surrounding the heating tube for a hot air device. BACKGROUND

[0002] Hot air tools typically consist of a heating tube containing a heating element and a fan that draws air through the tube, causing it to circulate around the heating element, heat up, and exit at a hot air outlet on the tube. The fan may be integrated into the hot air tool or be a separate unit, in which case the tool requires an external air supply. Depending on the air outlet temperature, the surface of the heating tube, particularly near the hot air outlet, can reach temperatures of up to 500°C to 600°C. To prevent burns, hot air tools are equipped with a protective sleeve or shield that surrounds the heating tube. This shield is also known as a protective tube or contact guard.

[0003] Especially with hot air hand tools for applications where force must be exerted on a workpiece with the hot air tool, such as draw welding using a hot air hand tool and a special nozzle, it is advantageous to hold or grip the tool as close as possible to the nozzle, i.e. at the air outlet end.

[0004] Possibilities for the design of the contact protection or protective tube of hot air devices are known from the state of the art.

[0005] US 3209988 A1 discloses a hot air device with a heating tube and a protective tube, wherein the protective tube has a hot air outlet end with at least one through-opening in the wall.

[0006] The heating element can be surrounded by a passive contact guard. This guard can be made of a material with low thermal conductivity, such as plastic. A disadvantage of this solution is that the guard must also maintain a sufficient distance from the heating element to prevent overheating, which increases the size of the hot air tool. However, a compact handheld hot air tool would be preferable.

[0007] As an alternative to passive contact protection, active cooling can be provided. Active cooling can be achieved, for example, by means of rear ventilation, particularly according to the "injector principle." In this process, a portion of the airflow or compressor air is blown into the space between the heating tube and the protective tube.

[0008] The inventors recognized that, particularly around the air outlet of the protective tube, areas with high temperatures (>60°C) can still occur, meaning the user can only handle it for extended periods while wearing work gloves. In practice, this can lead to repeated work interruptions while the hot air device cools down, and / or wearing work gloves to protect against the high temperatures hinders fine motor skills and thus the user's ability to work efficiently. BRIEF SUMMARY OF THE INVENTION

[0009] One objective of the present invention is to at least partially overcome the aforementioned disadvantages of the prior art. It would be desirable to provide a hot air device which, during operation, heats up only very slowly and minimally, particularly in areas that the user touches, so that the user can handle it for extended periods, possibly even without work gloves.

[0010] According to the invention, the problem is solved by providing a hot air device with a heating tube and a protective tube, wherein the protective tube surrounds the heating tube (at least partially) and is spaced apart from it, wherein the heating tube has a hot air outlet end, wherein the protective tube has a first main body and an air outlet end directed towards the hot air outlet end of the heating tube, wherein (transverse to a flow direction of the hot air stream through the heating tube) a non-uniform distance is provided between the protective tube and the heating tube, wherein the distance in the air outlet end is greater than the distance in an area of ​​the first main body adjacent to the air outlet end, in particular directly, and wherein the air outlet end of the protective tube has at least one through-opening in a wall, preferably in the area of ​​the distance widening.The term "gap" can refer to the so-called annular gap height between the heating pipe and the protective tube. In other words, a non-uniform annular gap height in the longitudinal direction of the hot air flow can be provided between the heating pipe and a protective tube surrounding the heating pipe, with one or more openings in the wall of the protective tube being provided in the area of ​​a change or relative expansion of the cross-section.

[0011] The hot air device can be, in particular, a handheld hot air device. The hot air device can have an integrated air supply or an external air supply.

[0012] Within the scope of the present disclosure, a tube is understood to be, in particular, a tubular body that is generally at least partially cylindrical or substantially cylindrical. A wall of the tube encloses the interior or volume of the tube along its length and forms the outer boundary of the tube. The protective tube according to the invention has an open end at which the air outlet is located. As will be clear to those skilled in the art, such an open end is not to be understood as a through-opening in the wall of the tube. In other words, the at least one through-opening is provided in a lateral wall of the protective tube.

[0013] By using a non-uniform and, at the air outlet end, larger distance between the protective tube and the heating tube, in combination with through-openings in the wall at the air outlet end, the surface temperature of the protective tube can be advantageously reduced considerably during operation of the hot air device. Particularly at the air outlet end, where conventional protective tubes of hot air devices exhibit particularly strong heating, the invention allows for a reduction in the surface temperature and a slower heating process.

[0014] In this case, the openings in the area of ​​the air outlet end can allow additional cool ambient air to be drawn into the space between the protective tube and the heating tube due to the airflow in the latter, which further cools the airflow, especially at the air outlet end, and thus the air outlet end itself.

[0015] In conjunction with the openings in the wall, the larger distance between the protective tube and the heating tube at the air outlet end not only reduces the heating of the protective tube by thermal radiation, especially at the air outlet end, but also improves the cooling effect with the additional ambient air drawn in through the openings.

[0016] The at least one opening in the wall is preferably located in the area of ​​the increased distance. This allows cooler ambient air to be drawn in advantageously. A further advantage of this arrangement in the area of ​​the increased distance is that it is clearly visible to the user from which section the additional cooling effect is provided. This can further simplify handling.

[0017] However, it is also possible that at least one through-opening is located after the area of ​​increased distance, or that one or more additional through-openings are located in the wall after the area of ​​increased distance. Furthermore, it is also possible that the one or more through-openings in the wall are located exclusively in the area of ​​increased distance. This avoids turbulence that could otherwise occur due to any additional through-openings after the area of ​​increased distance and achieves improved cooling airflow to the air outlet.

[0018] Advantageously, the reduced and slow heating of the protective tube lowers the risk of injury or burns to the user and allows the user to touch the protective tube for a longer period of time and especially without work gloves, which improves the workflow and the user's fine motor skills during work.

[0019] In a preferred embodiment, the protective tube has a non-uniform first inner diameter, wherein the first inner diameter is larger at the air outlet end than in an area of ​​the first main body immediately adjacent to the air outlet end.

[0020] Within the scope of this disclosure, the term "inner diameter of a pipe" refers in particular to the length of a segment between two points on an inner surface of the pipe wall, wherein both points lie in a plane perpendicular to a longitudinal direction of the pipe and wherein the segment passes through the centroid of the portion of the plane enclosed by the inner surface of the pipe wall. As will be known to those skilled in the art, the inner diameter of a pipe can be uniform, for example, if the pipe is cylindrical. As will also be known to those skilled in the art, the inner diameter of a pipe can be non-uniform. The inner diameter can be non-uniform along the length of the pipe if, for example, the pipe has thickenings or expansions or constrictions.The inner diameter of a pipe can be non-uniform along its circumference if, for example, the pipe is not cylindrical but prismatic with a polygonal base. The inner diameter of a pipe can also be non-uniform along its length and circumference.

[0021] This advantageously allows for a smooth, for example cylindrical, shape of the heating tube, which avoids a narrowing at the hot air outlet end and thus enables a wider distribution of the hot air over the workpiece.

[0022] In a preferred embodiment, the heating tube has a second main body and a non-uniform second outer diameter, wherein the second outer diameter is smaller at the hot air outlet end than in a region of the second main body immediately adjacent to the hot air outlet end.

[0023] This advantageously allows for a smooth, for example cylindrical, shape of the protective tube, which facilitates a secure grip or grasp by the user. Since the wall thickness of a heating tube is often relatively uniform, and a non-uniform outer diameter is analogously reflected in a non-uniform inner diameter, the non-uniform inner diameter of the heating tube can also be used for the sake of simplicity. In one embodiment, the heating tube can have a second main body and a non-uniform second inner diameter, wherein the second inner diameter is smaller at the hot air outlet end than in a region of the second main body immediately adjacent to the hot air outlet end. It is understood that the terms "first" and "second" are used here to distinguish between the diameters or elements of the protective tube and the heating tube.

[0024] In a preferred embodiment, the air outlet end can have at least two through-openings. In particular, the air outlet end can have at least two and at most 50 through-openings, especially at least six and at most 50.

[0025] Advantageously, more than one through-opening or a division into several through-openings allows for a beneficial cooling effect while maintaining advantageous mechanical stability at the air outlet end. This applies particularly to embodiments in which the at least one through-opening extends over more than 60% of the circumference of the protective tube.

[0026] Limiting the number of through-holes to a maximum of 50 advantageously ensures a sufficient size for each opening. The more through-holes are provided, the smaller they tend to be. Very small through-holes obstruct or slow down the airflow through them, potentially hindering the intake of additional ambient air. The proposed number of through-holes allows for both good stability and efficient intake of additional ambient air in this specific application.

[0027] In a preferred embodiment, at least one of the at least one through-opening can be circular or slot-shaped.

[0028] Circular openings are limited in size by the length of the air outlet end, which advantageously reduces the risk of small parts being sucked in through the opening.

[0029] Slotted openings advantageously allow an opening to extend over a larger portion of the circumference of the protective tube, thus reducing the number of openings while maximizing the size of each individual opening. Furthermore, a slotted opening allows the length of the air outlet to be kept short. This advantageously concentrates the cooling effect on the air outlet end of the protective tube, which is typically the area that heats up most intensely in conventional hot air devices.

[0030] In a preferred embodiment, the air outlet end can have a first section and a second section, wherein the second section is arranged between the first section and the first main body and the distance in the first section is greater than the distance in the second section.

[0031] This allows for a gradual increase in the distance at the air outlet end, which advantageously improves the flow characteristics of the airflow at the air outlet end by preventing a sudden drop in flow velocity.

[0032] In a preferred embodiment, the first section can have a uniform inner diameter over its entire length.

[0033] This advantageously stabilizes the airflow at the air outlet end, allowing sufficient additional ambient air to be drawn in through the openings. With increasing distance in the first section, the flow velocity can decrease, which can reduce the suction effect through the openings. Conversely, a decreasing inner diameter would increase the pressure in the protective tube, which can also reduce the suction effect.

[0034] The first section may have a non-uniform or a uniform first inner diameter along its circumference.

[0035] In a preferred embodiment, the second section can have a non-uniform first inner diameter, which in particular becomes larger towards the first section.

[0036] This can improve the flow characteristics of the airflow at the air outlet end and thus the heat dissipation compared to embodiments in which the second section has a non-uniform inner diameter, which becomes smaller towards the first section.

[0037] In a preferred embodiment, the first inner diameter in the second section can increase uniformly or (monotonically) continuously towards the first section.

[0038] This further improves the flow characteristics of the airflow at the air outlet, particularly with regard to the turbulence-free merging of the airflow flowing through the protective tube and the airflow flowing through the at least one through-opening that merges with it. Furthermore, the deposition of external contaminants on the second section or in the vicinity of the through-openings is reduced by preventing depressions.

[0039] In a preferred embodiment, the second section can be formed at a right angle to the first section.

[0040] Dies ermöglicht dem Nutzer vorteilhafterweise das Umfassen des Luftaustrittsendes mit einer (oder beiden) Händen, ohne dabei die Durchgangsöffnungen vollständig zu verschließen.

[0041] In a preferred embodiment, the at least one through-opening can be arranged in the first section and / or in the second section, in particular exclusively in the second section.

[0042] This allows the at least one through-hole to extend over a particularly large portion of the air outlet end, which promotes air circulation between the environment and the interior of the protective tube. This can contribute to cooling.

[0043] In a preferred embodiment, the at least one through-opening can be arranged exclusively in the second section.

[0044] This promotes a low-turbulence flow at the air outlet, as the merging of the airflow through the protective tube and the airflow through the at least one through-opening occurs predominantly in the second section. This improves heat dissipation with the airflow.

[0045] In a preferred embodiment, the second section can extend over at least 15% and at most 50% of the length of the air outlet end.

[0046] This can advantageously, particularly in embodiments in which the at least one through-opening is arranged exclusively in the second section, allow the airflow through the at least one through-opening to flow along a sufficiently long area of ​​the end of the protective tube in order to achieve effective cooling of the same.

[0047] In a preferred embodiment, the at least one through-opening can extend over at least 30% and at most 95% of the circumference of the protective tube, in particular over at least 50% and at most 95%.

[0048] This advantageously allows for sufficient cooling of the air outlet end or sufficient intake of additional ambient air.

[0049] In a preferred embodiment, the air outlet end can extend over at least 5% and at most 50% of the length of the protective tube.

[0050] It is advantageous for the air outlet end to extend over at least 5% of the protective tube, as this ensures that the airflow through the at least one through-opening flows along the protective tube for a sufficient distance to achieve effective cooling.

[0051] It is advantageous for the air outlet to extend over no more than 50% of the protective tube, as it is known that the end of the tube where the air exits heats up particularly strongly. Furthermore, extending it over more than 50% would cause the airflow through the at least one opening to also heat up increasingly as it travels through the interior of the protective tube, so that, as with conventional protective tubes, effective cooling would not be possible at the end of the tube, i.e., at the point where the airflow exits the tube. In addition, extending it over more than 50% would reduce the flow velocity within the protective tube due to the increased inner diameter at the air outlet, thus diminishing the cooling effect. Finally, the protective tube would have a significantly larger volume and therefore become less manageable.

[0052] In a preferred embodiment, the distance between the protective tube and the heating tube at the air outlet end can be at most 1.5 times greater than the distance in an area of ​​the first main body immediately adjacent to the air outlet end.

[0053] This can advantageously allow for sufficient handling of the protective tube and a sufficient airflow along the protective tube for effective cooling.

[0054] In a preferred embodiment, the protective tube surrounds the heating tube at least partially and is spaced apart from it, so that a gap is formed between the heating tube and the protective tube, wherein the hot air device is configured such that a first airflow can be directed through the heating tube towards the hot air outlet end, so that the first airflow is heated by a heating element and exits the heating tube through the hot air outlet end, and a second airflow can be directed in the same direction as the first airflow through the space between the heating tubes, so that the second airflow reduces the transfer of heat from the heating tube to the protective tube, causes a third airflow at the air outlet end through the at least one through-hole into the space between the heating tubes and exits the protective tube through the air outlet end together with the third airflow.

[0055] Advantageously, with such a hot air device, the surface temperature of the entire protective tube can be significantly reduced during operation. Particularly at the air outlet end, where conventional protective tubes for hot air devices tend to overheat, the opening allows for a reduction in surface temperature, and the heating process occurs more slowly.

[0056] The openings allow cool ambient air to be drawn into the air outlet end due to the airflow in it, which further cools the airflow, especially in the air outlet end, and thus the air outlet end itself.

[0057] Further advantages and features will become apparent from the following description and the accompanying drawing. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWING

[0058] The following section provides a detailed explanation of non-restrictive embodiments with reference to the drawing. Fig. 1 shows a section of a hot air device 100 comprising a protective tube 10, a heating tube 24, and a distance between the protective tube and the heating tube. Fig. 2 shows a side view of a protective tube 10 of a hot air device 100, wherein the at least one through-opening 22 is slot-shaped. Fig. 3 shows a side view of a protective tube 10 of a hot air device 100, wherein the at least one through-opening 22 is circular. Fig. 4 shows a side view of a protective tube 10 of a hot air device 100, wherein the at least one through-opening 22 is slot-shaped and is arranged in a first section 18 and in a second section 20. Fig. 5 shows a schematic longitudinal section through a hot air device 100. Fig. 6A shows a thermal image of a conventional hot air device for comparison. Fig. 6B shows a thermal image of a hot air device 100. DETAILED DESCRIPTION

[0059] Identical or corresponding features are marked with the same reference symbols in the figures.

[0060] Fig. 1 Figure 1 shows a portion of a hot air device 100. The hot air device 100 has a protective tube 10 and a heating tube 24, wherein the protective tube (10) surrounds the heating tube (24) and is spaced apart from it. The hot air device 100 can be a handheld hot air device. However, the hot air device 100 can be any type of hot air device, for example, a built-in hot air device. The illustration is therefore focused on the area with the heating tube and protective tube.

[0061] The heating tube 24 has a hot air outlet end 30, a second main body 13 and a second inner diameter 17a, 17b.

[0062] In the hot air outlet end 30, the second inner diameter 17b of the heating tube 24 in the example shown is 0.93 times larger than the second inner diameter 17a in a region 13a of the second main body 13 immediately adjacent to the hot air outlet end 30. The inner and outer diameters differ in the example shown only by their (uniform) material thickness, so for the sake of simplicity, reference can be made to the inner diameter. The explanations apply analogously with regard to the outer diameter.

[0063] In other preferred embodiments, the second inner diameter in the hot air outlet end 30 can be smaller and at most 0.5 times larger than the second inner diameter 17a in a region 13a of the second main body 13 immediately adjacent to the hot air outlet end 30.

[0064] In the example shown, the second inner diameter 17a, 17b is non-uniform, with the second inner diameter 17a, 17b being smaller in the hot air outlet end 30 than in an area 13a of the second main body 13 immediately adjacent to the hot air outlet end 30.

[0065] In other preferred embodiments, the heating tube 24 can have a uniform second inner diameter 17a, 17b.

[0066] The protective tube 10 has a first main body 12, an air outlet end 14 and a first inner diameter 16.

[0067] The air outlet end 14 has at least one through-opening 22 in a wall and is directed towards the hot air outlet opening 30 of the heating tube 24.

[0068] In the example shown, the distance at the air outlet end 14 is 2.25 times greater than the distance between the protective tube 10 and the heating tube 24 in an area 12a of the first main body 12 immediately adjacent to the air outlet end 14.

[0069] In other preferred embodiments, the distance in the air outlet end 14 can be at least larger and at most 10 times larger than the distance in a region 12a of the main body 12 immediately adjacent to the air outlet end 14.

[0070] In the example shown, the first inner diameter 16 is uniform, but a non-uniform distance is provided between the protective tube (10) and the heating tube (24), the distance being greater in the air outlet end 14 than in an area 12a of the first main body 12 immediately adjacent to the air outlet end 14.

[0071] In other preferred embodiments, the protective tube 10 can have a non-uniform first inner diameter 16.

[0072] Fig. 2 Figure 1 shows a protective tube 10 for the hot air device 100. The protective tube 10 has a non-uniform first inner diameter 16a, 16b, 16c.

[0073] In other preferred embodiments, the first inner diameter 16a, 16b, 16c is uniform.

[0074] The main body 12 is tubular and has a first inner diameter 16a that is essentially uniform over the length of the first main body 12 and two open ends.

[0075] In other preferred embodiments, the first main body 12 can have any other shape, as long as it is substantially tubular, so that it fulfills the ordinary function of a protective tube. In particular, the first main body 12 can have a first inner diameter 16a that is non-uniform along its length and / or circumference.

[0076] The air outlet end 14 has a first section 18, a second section 20 and through-openings 22 in a wall and is directed towards the hot air outlet opening of the heating tube.

[0077] In the air outlet end 14, the first inner diameter 16b, 16c of the protective tube 10 in the example shown is 1.1 times larger than the first inner diameter 16a in a region 12a of the first main body 12 immediately adjacent to the air outlet end 14.

[0078] In other preferred embodiments, the first inner diameter in the air outlet end 14 can be at least larger and at most 1.5 times larger than the first inner diameter 16a in a region 12a of the first main body 12 immediately adjacent to the air outlet end 14.

[0079] In the example shown, the air outlet end 14 extends over 10% of the length of the protective tube 10.

[0080] In other preferred embodiments, the air outlet end 14 can extend over at least 5% and at most 50% of the length of the protective tube 10.

[0081] In the example shown, the first section 18 has a uniform first inner diameter 16b along its entire length.

[0082] In other preferred embodiments, the first section 18 can have a first internal diameter 16b that is non-uniform along its length.

[0083] The second section 20 is arranged between the first section 18 and the first main body 12.

[0084] In the example shown, the second section 20 extends over 15% of the length of the air outlet end 14.

[0085] In other preferred embodiments, the second section 20 can extend over at least 15% and at most 50% of the length of the air outlet end 14.

[0086] In the second section 20, the first inner diameter 16c in the example shown becomes uniformly or steadily larger towards the first section 18.

[0087] In other preferred embodiments, the first inner diameter 16c in the second section 20 can increase unevenly or discontinuously towards the first section 18, or the second section 18 can be arranged perpendicular to the first section 18.

[0088] In the Fig. 2 In the preferred embodiment shown, 8 through-openings 22 are provided. In other preferred embodiments, at least one through-opening 22 may be provided, preferably at least 2 and at most 50, more preferably at least 6 and at most 50.

[0089] The through-openings 22 in the example shown are slot-shaped, are arranged regularly or symmetrically along the circumference of the air outlet end 14, extend along 80% of the circumference of the air outlet end 14 and are identical to each other.

[0090] Fig. 3 Figure 1 shows another embodiment of the protective tube 10 for the hot air device with 12 through-openings 22, wherein the through-openings 22 in the example shown are circular, regularly or symmetrically arranged along the circumference of the air outlet end 14, extend along 50% of the circumference of the air outlet end and are identical to each other.

[0091] In other preferred embodiments, the at least one through-opening 22 can have any shape, be arranged irregularly or asymmetrically along the circumference of the air outlet end 14, extend along at least 30% and at most 95% of the circumference of the air outlet end 14 and / or not all be identical to each other.

[0092] The passage openings 22 are in the Fig. 1 and 2 The preferred embodiments shown are arranged exclusively in the second section 20.

[0093] Fig. 4 Figure 1 shows another preferred embodiment of the protective tube 10 for the hot air device 100 with 24 through-openings 22, wherein the at least one through-opening 22 is arranged in the first section 18 and in the second section 20.

[0094] In other preferred embodiments, the at least one through-opening 22 can be arranged in the first section 18 and / or in the second section 20, for example exclusively in the first section 18.

[0095] Fig. 5 Figure 1 shows a schematic longitudinal section of a part of a hot air device 100. The hot air device 100 comprises a protective tube 10 and a heating tube 24. The protective tube 10 surrounds the heating tube 24 at least partially and is spaced apart from it. Due to this spacing, a gap 26 is formed between the protective tube 10 and the heating tube 24. The heating tube 24 has a hot air outlet 30 and is configured to accommodate a heating element (not shown).

[0096] The hot air device 100 is configured in such a way that when the hot air device 100 is in operation A first airflow 32 is directed through the heating tube 24 towards the hot air outlet end 30, so that the first airflow 32 is heated by a heating element and exits the heating tube 24 through the hot air outlet end 30, and a second airflow 34 can be directed in the same direction as the first airflow 32 through the space 26, so that the second airflow 34 reduces the transfer of heat from the heating tube 24 to the protective tube 10, causes a third airflow 36 at the air outlet end 14 through the at least one through-opening 22 into the space 26 and exits the protective tube 10 through the air outlet end 14 together with the third airflow 36.

[0097] The first airflow 32 is expelled as hot air from the hot air device 100 after being heated by a heating element (not shown).

[0098] The second airflow 34 heats up to a lesser extent compared to the first airflow 32 and thereby extracts heat from the heating tube 24 and the protective tube 10, which is consequently carried away by the second airflow 34 and expelled from the hot air device 100.

[0099] At the air outlet end 14, the second airflow 34 passes through the at least one through-opening 22 and, as is assumed, causes the third airflow 36 to flow or be drawn in through the at least one through-opening 22 due to its flow velocity.

[0100] The second airflow 34 and the third airflow 36 flow together through the air outlet end 14 and heat up to a lesser extent compared to the first airflow 32, thereby extracting heat from the heating tube 24 and the protective tube 10, which is consequently carried away by the second airflow 34 and the third airflow 36 and expelled from the hot air device 100.

[0101] Fig. 6 shows a thermal image of a conventional hot air device as a comparison example ( Fig. 6A ) and a thermal image of a hot air device 100 ( Fig. 6B ) after operation over an identical, typical application period.

[0102] The surface of the protective tube of a conventional hot air device heats up during prolonged operation to approximately 33°C at position 38 on the main body of the protective tube and to approximately 44°C at position 40 at the air outlet end. The protective tube is therefore 11°C hotter at position 40 (air outlet end) than at position 33 on the main body.

[0103] The surface of the protective tube 10 of the hot air device 100 heats up during operation to approximately 31°C at position 42 on the first main body 12 of the protective tube 10, and to only approximately 38°C at position 44 on the air outlet end 14. The protective tube is therefore 7°C hotter at position 44 at the air outlet end than at position 42 on the first main body. Compared to the conventional protective tube, the difference can thus be reduced by 4°C with the proposed solution.

[0104] Accordingly, heating of the protective tube 10 is reduced and slowed down compared to a conventional protective tube, both at the main body 12 and at the air outlet end 14, especially at the air outlet end 14.

[0105] In summary, the solutions proposed herein can provide an improved hot air tool. In particular, the temperature at the air outlet end of a protective tube of the hot air tool can be reduced, allowing the user to handle it for a longer period of time and possibly even without work gloves.

Claims

1. Hot air device (100) comprising - a heating tube (24), and - a protective tube (10), wherein the protective tube (10) surrounds the heating tube (24) and is spaced apart from it, wherein the heating tube (24) comprises a hot air outlet end (30), wherein the protective tube (10) comprises a first main body (12) and an air outlet end (14) directed towards the hot air outlet end (30) of the heating tube (24), wherein a non-uniform distance is provided between the protective tube (10) and the heating tube (24), wherein the distance in the air outlet end (14) is greater than the distance in a region (12a) of the first main body (12) adjacent to the air outlet end (14), and wherein the air outlet end (14) of the protective tube (10) comprises at least one pass-through opening (22) in a wall, preferably in the region of the widening of the distance.

2. Hot air device (100) according to claim 1, wherein the protective tube (10) has a non-uniform first inner diameter (16a, 16b, 16c), wherein the first inner diameter (16a, 16b, 16c) is larger in the air outlet end (14) than in a region (12a) of the first main body (12) directly adjacent to the air outlet end (14).

3. Hot air device (100) according to any of the preceding claims, wherein the heating tube (24) comprises a second main body (13) and a non-uniform second outer diameter (17a, 17b), wherein the second outer diameter (17a, 17b) is smaller in the hot air outlet end (30) than in a region (13a) of the second main body (13) directly adjacent to the hot air outlet end (30).

4. Hot air device (100) according to any of the preceding claims, wherein the air outlet end (14) comprises at least 2 pass-through openings (22), in particular at least 2 and no more than 50 pass-through openings (22), in particular at least 6 and no more than 50.

5. Hot air device (100) according to claim 4, wherein the at least 2 pass-through openings (22) are arranged regularly or symmetrically along a circumference of the protective tube (10).

6. Hot air device (100) according to any of the preceding claims, wherein at least one of the at least one pass-through opening (22) is circular or slit-shaped.

7. Hot air device (100) according to any of the preceding claims, wherein the air outlet end (14) comprises a first section (18) and a second section (20), wherein the second section (20) is arranged between the first section (18) and the main body (12) and the distance in the first section (18) is greater than the distance in the second section (20), in particular wherein the first section (18) has a uniform first inner diameter (16a, 16b, 16c) over its entire length.

8. Hot air device (100) according to claim 7, wherein the second section (20) has a non-uniform first inner diameter (16a, 16b, 16c) which increases towards the first section (18), in particular wherein the first inner diameter (16a, 16b, 16c) in the second section (20) increases evenly or continuously towards the first section (18).

9. Hot air device (100) according to claim 7, wherein the second section (20) is formed at a right angle to the first section (18).

10. Hot air device (100) according to any of claims 7 to 9, wherein the at least one pass-through opening (22) is arranged in the first section (18) and / or in the second section (20), in particular exclusively in the second section (20).

11. Hot air device (100) according to any of claims 7 to 10, wherein the second section (20) extends over at least 15% and no more than 50% of the length of the air outlet end (14).

12. Hot air device (100) according to any of the preceding claims, wherein the at least one pass-through opening (22) extends over at least 30% and no more than 95% of a circumference of the protective tube (10), in particular over at least 50% and no more than 95%.

13. Hot air device (100) according to any of the preceding claims, wherein the air outlet end (14) extends over at least 5% and no more than 50% of the length of the protective tube (10).

14. Hot air device (100) according to any of the preceding claims, wherein the distance between the protective tube (10) and the heating tube (24) in the air outlet end (14) is no more than 1.5 times, in particular no more than 1.2 times, as large as the distance in a region (12a) of the first main body (12) directly adjacent to the air outlet end (14).

15. The hot air device (100) according to any of the preceding claims, wherein the protective tube (10) surrounds the heating tube (24) at least in sections and is spaced apart from it, so that an intermediate space (26) is formed between the heating tube (24) and the protective tube (10), wherein the hot air device (100) is configured such that - a first air flow (32) can be directed through the heating tube (24) in direction of the hot air outlet end (30), such that the first air flow is heated by a heating element and exits the heating tube (24) through the hot air outlet end (30), and - a second air flow (34) in the same direction as the first air flow (32) can be directed through the intermediate space (26), such that the second air flow reducing a heat transfer from the heating tube (24) to the protective tube (10) causes a third air flow (36) at the air outlet end (14) through the at least one pass-through opening (22) into the intermediate space (26) and exits together with the third air flow (36) from the protective tube (10) through the air outlet end (14).