EP3387329B1

EP3387329B1 - A supply air device

Info

Publication number: EP3387329B1
Application number: EP16872476.3A
Authority: EP
Inventors: Jari HEINOVAARA
Original assignee: Alme Solutions Oy
Current assignee: Alme Solutions Oy
Priority date: 2015-12-09
Filing date: 2016-12-09
Publication date: 2023-07-26
Anticipated expiration: 2036-12-09
Also published as: EP3387329C0; CN108431508B; EP3387329A4; CN108431508A; FI20155928A; WO2017098088A1; FI127646B; EP3387329A1

Description

Field of the invention

The present invention relates to a supply air device comprising a nozzle channel structure directing a supply air flow into a room. The supply air flow comprises primary air and secondary air. The primary air flow entrains a flow of secondary air flow from the room to flow to the supply air device and further to return to the room. Furthermore, the invention relates to a nozzle channel structure for a supply air device.

Background

For temperature controlling of rooms, it has become common to provide the rooms with supply air devices, wherein primary air supplied from a central ventilation system is blown from nozzles inside the supply air device to be mixed in a discharge channel with a secondary air flow from the room entrained by the supply air flow. The air mixture formed by the primary and secondary air is led from the supply air device into the room as the supply air flow. The secondary air entrained from the room enters the supply air device via a temperature controlling device which enables the temperature controlling of the secondary air. This kind of supply air device controls internal thermal conditions of the room.
In some cases the secondary air is led instead of or in addition to a temperature controlling device through a filter in order to remove impurities from indoor air. The filter causes a flow resistance, which is not advantageous for the function of the supply air device. The flow resistance reduces the amount of secondary air flow, wherein the filtered secondary air flow does not have a significant effect on the quality of indoor air or temperature of indoor air, when the supply air device comprises a temperature controlling device. In other words, the filter of the supply air device restricts the secondary air flowing through the filter, resulting in an excessive reduction in removing impurities and in the temperature controlling efficiency of the supply air device comprising the temperature controlling device.
By increasing the primary air flow of the central ventilation system, it may be possible to increase the secondary air flow and therefore air purification and/or temperature controlling that is cooling or heating. However, among other things, increasing the primary air flow increases energy consumption and may lead to a need for bigger channels for the air flows of the central ventilation system. Increase of the primary air flow can also increase the size of the ventilation system, for example, size of air ducts and/or air handling units.
DE 3114528 discloses a control device for an air-distributing device for air-conditioning rooms for outside-air supply or for heating or cooling. The control device has an air-supply arrangement and an air blowingout arrangement with a primary blowpipe for a constant basic-load air quantity, a secondary blowpipe for a variable air quantity and a volumecontrol arrangement assigned to the secondary blowpipe, and separate supply pipes in the air-supply arrangement for hot air and cold air.
GB 1349961 discloses a ventilation system for buildings with an outer wall having fixed glazing, in which window elements and panels are fixed to the outside of hollow columns projecting into the building space. wherein the hollow columns are constructed as air-supply ducts for primary air and are connected together by a horizontal conduit connected to a central air-conditioning plant, means being provided on the hollow columns through which the primary air can flow laterally from the columns for supply to the window elements.

Summary

It is an aim of the present invention to provide a novel nozzle channel structure increasing an air circulating efficiency (secondary air flow (litres/second (l/s))/ primary air flow (l/s)) of a supply air device. The nozzle channel structure is arranged to be fixed in a distance from the bottom of the supply air device forming a circulation space between the bottom of the supply air device and the nozzle channel structure for secondary air flows. The nozzle channel structure is further arranged to be fixed in a distance from a side of the supply air device also forming the circulation space between the side of the supply air device and the nozzle channel structure for secondary air flows. The side is the side outer side of the supply air device. It is another aim of the present invention to provide a supply air device comprising the novel nozzle channel structure.
According to a first embodiment, there is provided a supply air device comprises a nozzle channel structure comprising at least one nozzle and a mixing chamber. The nozzle channel structure is arranged in a distance from the bottom of the supply air device forming a circulation space between the bottom of the supply air device and the nozzle channel structure. Primary air is led to the nozzle channel structure and from the nozzle channel structure to the mixing chamber through said at least one nozzle as at least one primary air flow. Said at least one primary air flow entrains secondary air from outside the supply air device to flow to the mixing chamber through the circulation space and the primary air and secondary air are arranged to be mixed in the mixing chamber before flowing out of the supply air device.
According to an embodiment, the nozzle channel structure comprises a plurality of nozzles. According to an embodiment, the primary air is led to the nozzle channel structure from a central ventilation system or by using a separate fan. According to an embodiment, the nozzle channel structure is a peripherally closed duct system. According to an embodiment, the nozzle channel structure comprises at least two separate duct sections. According to an embodiment, the nozzle channel structure is formed from a duct having straight shape. According to an embodiment, the nozzle channel structure comprises separate ducts. According to an embodiment, the supply air device further comprises a filter.
According to a second embodiment, there is provided a supply air device, wherein the supply air device further comprises a temperature controlling device for cooling or heating the secondary air, the secondary air is led through the temperature controlling device into the mixing chamber.
According to an embodiment, the supply air device comprises two or more nozzle channel structures with separate mixing chambers. According to an embodiment, the nozzle channel structure comprises at least one duct which comprises a plurality of nozzles and wherein the nozzle channel structure is arranged to be fastened in a distance from the bottom of the supply air device for forming a circulation space between the bottom of the supply air device and the nozzle channel structure and wherein primary air is led to the nozzle channel structure and from the nozzle channel structure to the mixing chamber through said at least one nozzle as at least one primary air flow and wherein said at least one primary air flow entrains secondary air from outside the supply air device to flow to a mixing chamber of the supply air device and wherein at least a part of said secondary air flows to the mixing chamber through the circulation space. According to an embodiment, the nozzle channel structure is a peripherally closed duct system. According to an embodiment, the nozzle channel structure comprises at least two separate duct sections. According to an embodiment, the nozzle channel structure is formed from a duct having straight shape. According to an embodiment, the nozzle channel structure comprises separate ducts. According to an embodiment, locations of the nozzle channel structure or a part of the nozzle channel structure inside a supply air device are adjustable.

Description of the Drawings

In the following, various embodiments of the invention will be described in more detail with reference to the appended drawings, in which

Fig. 1: shows a cross-sectional view of a prior art supply air device;
Fig. 2: shows a perspective image of a supply air device comprising a nozzle channel structure according to an example embodiment;
Fig. 3: shows a perspective image of a supply air device comprising a nozzle channel structure according to an example embodiment;
Fig. 4: shows a primary air flow wall of a supply air device comprising a nozzle channel structure according to an example embodiment;
Fig. 5a-f: show nozzle channel structures according to an example embodiment;
Fig. 6: shows a cross-sectional view of a supply air device and an example route of air circulation inside the supply air device. According to the invention the nozzles are however provided as perforations without collars;

Fig. 7: shows a simplified cross-sectional view of a part of a supply air device comprising two nozzle channel structures according to an example embodiment. According to the invention the nozzles are however provided as perforations without collars;

Fig. 8: shows a simplified supply air device according to an example embodiment; and
Fig.9: shows a simplified supply air device in use according to an example embodiment.

Description of Example Embodiments

The supply air device according to the invention and arranged to be fixed to the ceiling or wall is based on the idea comprises a nozzle channel structure. The term supply air device covers in this context also local exhaust ventilation devices. The nozzle channel structure of the supply air device used for supplying primary air may be provided as a peripherally closed duct system, as separate ducts forming a duct system or as a duct system comprising at least two separate duct sections. The sections may be connected together, for example, by connecting parts or the duct system may comprise at least two separate duct sections in which case a closed duct system is divided to at least two separate duct sections by a compartmentation wall(s). The nozzle channel structure may have various shapes. It may have, for example, a shape of a hollow rectangle with or without round corners, toroid, hollow oval or any other suitable shape when the supply air device is fixed to a ceiling or wall of a room and seen from below. According to the invention, a cross-section of the at least one duct of the duct system of the nozzle channel structure is circular or oval. The nozzle channel structure comprises a plurality of nozzles that are perforations without collars arranged on the perimeter of the nozzle channel structure in a distance from each other. The number of nozzles, the diameter and shape of nozzles, the locations of nozzles relative to the longitudinal line of one or more parts of the nozzle channel structure and/or the distance between nozzles may be selected to be suitable for the purpose of the supply air device. It is also possible that the location or the diameter or the shape of nozzle perforations or the distance between nozzles of the same nozzle channel structure vary. The nozzle channel structure may be made, for example, of metal or other suitable material. Ducts or parts of nozzle channel structures may have different cross-sections. A cross-section of duct(s) or part(s) of a nozzle channel structure may be non-angled or at least the underside i.e. the lower part of duct(s) or part(s) of the nozzle channel structure that is towards the floor may be non-angled. When the lower part of duct(s) or part(s) of the nozzle channel structure are non-angled, the cross section is at least partly non-angeled. Non-angled means that there is no angles in the cross-section of the structure or in the cross-section of the lower part of duct(s) or part(s) of the nozzle channel structure. Flowing air inside the supply air device turns towards surface of the duct or part of the nozzle channel structure, and flows along the surface towards nozzles. This is due to the coanda phenomenon. An angle in the structure may cause detaching of the flowing air from the surface. Detaching of the flowing may decrease entrainment of the secondary air which may in turn decrease air circulation effectiveness. The non-angled cross-section of duct(s) or part(s) of a nozzle channel structure may be, for example circular, or a shape of oval or drop etc. However, the cross-section of duct(s) or part(s) of a nozzle channel structure may also be rectangular. Furthermore, cross-sections of ducts/parts of one nozzle channel structure may vary. For example, one or more part(s) of a nozzle channel structure may have rectangular shape and one or more other part(s) of the same nozzle channel structure may have circular shape. According to the invention, a cross-section of the at least one duct of the duct system of the nozzle channel structure is however circular or oval. The nozzle channel structure may be formed from a uniform channel or channel modules with a monolithic profile, which channel modules are configured to be fastened, for example, one after the other, so that each nozzle channel module constitutes a part of the nozzle channel structure.
Inside the supply air device, the nozzle channel structure is arranged in a distance from a bottom of the supply air device. The bottom of the supply air device is the part of the supply air device that is the upper part of the supply air device when it is fixed to the ceiling or towards the ceiling when it is fixed to the wall. When the nozzle channel structure is arranged in a distance from the bottom of the supply air device, it increases entrainment of the secondary air by enabling circulating of the secondary air from a first side (a center side) of the primary air flow to the other side of the primary air flow through the circulating space between the bottom of the supply air device and the nozzle channel structure, wherein the other side is between the primary air flow and an outer wall of a discharge channel of the supply air device. The air supplied to the conditioned room from air nozzles of the nozzle channel structure of the supply air device is called primary air. The air may be supplied to the conditioned room, for example, from the central ventilation system or from the same room, from some other space/room or from outdoors by using a separate fan. Whereas, secondary air is drawn back into the supply air device to be mixed with primary air. The arrangement according to the invention increases the secondary air flow by increasing entrainment of the secondary air, thereby enhancing the purification or temperature controlling of air in the room, if the supply air device is also equipped with a filter and/or a temperature controlling device. The filter causes a flow resistance, which reduces the amount of secondary air flow. If an amount of secondary air decreases, the filtered secondary air flow may not have a significant effect on the quality or temperature of indoor air. By the nozzle channel structure the amount of secondary air may be increased and the quality and/or temperature of indoor air can be kept on an effective level.
Figure 1 shows a cross-sectional view of a prior art supply air device 10 arranged to be installed in a ceiling or wall of a room. Primary air is led via a supply air duct 11 to a supply air chamber 12 of the supply air device 10 from the outside of the device 10, normally from a central ventilation system. From the supply air chamber 12 the primary air is led through air nozzles 13 into a mixing chamber 14 located inside the supply air device 10, at a relatively high rate. The primary air flow blown into the mixing chamber 14 entrains secondary air 16 from the room through a circulation air opening 15 to the supply air device 10 and further to the mixing chamber 14. Primary air flowing from adjacent nozzles 13 forms a primary air flow wall 17 in the mixing chamber 14.
In this kind of supply air device 10, mainly only inner side of air flows of that wall that are towards the circulation air opening 15 entrains the secondary air 16, because the secondary air 16 does not pass through the wall 17 or only a small amount of the secondary air 16 passes through the wall 17 in order to be entrained by the other side of the wall i.e. the sides of the flows that are towards the outer walls of the supply air device 10. The passing of the secondary air 16 through the primary air flow wall 17 is the more difficult the closer the nozzles. In the mixing chamber 14 primary air and secondary air 16 will be mixed. From the mixing chamber 14, the mixture of primary air and secondary air flows into the room.
When the entraining is used mainly on only one side of the primary air flow wall, the air circulation effectiveness is not as effective as when more than one side of air flows are used. The term air circulation effectiveness refers to secondary air (l/s) / primary air (l/s).
Figure 2 shows a simplified perspective image of a supply air device 20 comprising a nozzle channel structure 21 according to the example embodiment and arranged to be installed in a ceiling or wall of a room. Primary air may be led via a supply air duct (not shown in the figure 2) to a supply air chamber 22 of the supply air device 20 from the outside of the supply air device 20, normally from a central ventilation system. From the supply air chamber 22 the primary air may be led to the nozzle channel structure 21 via one or more supply air openings (shown in figure 3). The primary air may be led to the nozzle channel structure 21, for example, via supply air openings that are arranged to at least one corner of the hollow rectangle shaped nozzle channel structure 21. Supply air openings may also be arranged to at least one other part(s) of the nozzle channel structure 21.
From the nozzle channel structure 21 the primary air may be led through air nozzles 23 of the nozzle channel structure 21 into a mixing chamber 24 located inside the supply air device 20. The primary air flow blown into the mixing chamber 24 may entrain secondary air from the room through a circulation air opening 25 into the supply air device 20 and further into the mixing chamber 24. Primary air flowing from adjacent nozzles 23 may form a primary air flow wall. Typically in a prior art solution as already mentioned above only inner side of air flows of that wall that are towards the circulation air opening 25 entrains the secondary air, because the secondary air does not pass through the wall or only small amount of the secondary air passes the wall in order to be entrained by the other side of the wall i.e. the sides of the flows that are towards the outer walls of the supply air device 20. The passing of the secondary air through the primary air flow wall is the more difficult the closer the nozzles 23 are. However, the use of the nozzle channel structure 21 which is attached at a distance from the bottom 26 of the supply air device 20 allows secondary air to find its way i.e. to circulate also to the other side of the primary air flow wall through the circulation space between the upper part of the nozzle channel structure 21 and the bottom 26 of the supply air device 20. In the mixing chamber 24 primary air and secondary air will be mixed. From the mixing chamber 24, the mixture of primary air and secondary air flows to the room.
Figure 3 shows a simplified perspective image of a supply air device 30 comprising a nozzle channel structure 31 according to the example embodiment and arranged to be installed in a ceiling or wall of a room. The nozzle channel structure 31 is again attached at a distance from the bottom of the supply air device 30. The supply air device 30 comprises also a filter 36. Primary air may be led into the supply air device 30 via a supply air duct 37. Inside the supply air device 30 primary air is led into a supply air chamber 32. From the supply air chamber 32 the primary air is led to the nozzle channel structure 31 comprising a plurality of air nozzles (not shown) via one or more supply air openings 38. From the nozzle channel structure 31 the primary air is led through air nozzles of the nozzle channel structure 31 into a mixing chamber 34 of the supply air device 30. The primary air flow blown into the mixing chamber 34 entrains secondary air from the room through a circulation air opening 35 into the supply air device 30. Inside the supply air device 30 the secondary air flows through the filter 36 on its way to the mixing chamber 34. At least part of the secondary air circulates through the circulation space between the nozzle channel structure 31 and the bottom of the device 30 before it mixes with the primary air in the mixing chamber 34. From the mixing chamber 34, the mixture of primary air and filtered secondary air flows into the room.
However, a supply air device according to an embodiment of the invention may comprise in addition to or instead of a separate filter or filter arrangement. And the secondary air may pass via the filter and/or a temperature controlling device, for example, a heat exchanger when flowing into the mixing chamber. The secondary air flow can be led in whole or in part through the filter. Advantageously, the cross-sectional area of the filter covers the whole secondary air flow. It is also possible to arrange the filter to the mixing chamber in such a way that both the primary air and the secondary air are led through the filter before entering to the room. In a corresponding manner, the secondary air flow may be temperature controlled in whole, or only a part of the secondary air flow is passed through the temperature controlling device. Alternatively, the supply air device may be equipped with a heat exchanger bypass plate, wherein the need of temperature controlling can be adjusted according to the load. There may be a water flow inside the temperature controlling device. The need for temperature controlling the air flow may vary, and the adjustment may be made by changing the amount or temperature of the water flow of the temperature controlling device. The supply air device may also be used solely for the purification of air, wherein the device comprises no temperature controlling device. The filter or filter arrangement may be arranged between a circulated air opening and a mixing chamber through which the secondary air flow is led. The filter or filter arrangement may be an electric particle filter, an electrostatic precipitator, a fabric filter made of electret material, an electric fabric filter, a gas filter or any other suitable filter. If the filter is an electric particle filter, the supply air device further comprises an ionizer arranged to charge airborne impurity particles of the secondary air flow by means of ions produced by corona discharge, placed on the secondary air flow before the filter.
It should be noted that when the entraining is used on both sides of the primary air flow wall as, for example, in the supply air devices 20, 30 of figures 2 and 3, the greater the air circulation effectiveness is. The term air circulation effectiveness refers to secondary air (l/s) / primary air (l/s). The air circulation effectiveness is important, for example, in situations where a certain amount of air should be purified by a supply air device. For example, without the nozzle channel structure, supply air devices may have a circulation effectiveness value of 2 and with the nozzle channel structure a value of 5. The air circulation effectiveness may be more than double when the nozzle channel structure is used.
Figure 4 shows a primary air flow wall 40 provided by a nozzle channel structure 42 according to the example embodiment. The air flow wall 40 is provided by adjacent nozzles 41 of the nozzle channel structure 42 by leading primary air through air nozzles 41 at a relatively high rate.
Figure 5a shows a nozzle channel structure according to an example embodiment. The nozzle channel structure 50 has a shape of a rectangle and it comprises a plurality of nozzles 51 at each side of the rectangle. Locations of nozzles relative to the longitudinal line of one or more parts of the nozzle channel structure 50 can vary. In this embodiment, locations of nozzles relative to the longitudinal line 52 of one side/part of the nozzle channel structure 53 vary. Figure 5b shows a nozzle channel structure according to an example embodiment. This nozzle channel structure 50 has a shape of a rectangle with round corners and it comprises a plurality of nozzles 51. Figure 5c shows a nozzle channel structure according to an example embodiment. This nozzle channel structure 50 has a shape of a toroid and it comprises a plurality of nozzles 51. Figure 5d shows a nozzle channel structure according to an example embodiment. This nozzle channel structure 50 has a shape of an oval and it comprises a plurality of nozzles 51. Each nozzle channel structure 50 of figures 5a-5d comprises one or more supply air openings. Via one or more supply air openings the primary air is led to the nozzle channel structure 50 from a supply air chamber or directly from a supply air duct.
Figure 5e shows a nozzle channel structure according to an example embodiment. This nozzle channel structure 50 has separate ducts 54, which are not connected to each other. Each duct comprises one or more supply air openings. Via one or more supply air openings the primary air is led to each duct 54 of the nozzle channel structure 50 from a supply air chamber or directly from a supply air duct. Also this nozzle channel structure comprises a plurality of nozzles 51. The ducts 54 may have one open end or both ends may be open. The ducts 54 may be connected together by corner pieces so that the air can flow from one duct 54 to at least one other duct 54 or the ducts 54 may be such that they are not connected to each other.
Figure 5f shows a nozzle channel structure according to an example embodiment. This nozzle channel structure 50 is formed from a duct 54 having straight shape. This nozzle channel structure 50 comprises a slit nozzle 51.
It should be noted, that in addition to a shape a cross-section(s) of nozzle channel structure may vary. It may be triangular, circular rectangular, oval or any other suitable shape. According to the invention, a cross-section of the at least one duct of the duct system of the nozzle channel structure is however circular or oval.
Figure 6 shows a cross-sectional view of a supply air device 60 according to an example embodiment. Figure 6 also shows an example route of air circulation inside the supply air device 60. Primary air 61 is led into the supply air device 60 via a supply air duct (not shown). Inside the supply air device 60 primary air 61 is led into a supply air chamber 62. From the supply air chamber 62 the primary air 61 is led to a nozzle channel structure 63 comprising a plurality of air nozzles 64. From the nozzle channel structure 63 the primary air 61 is led through air nozzles 64 to a mixing chamber 65. The primary air 61 blown into the mixing chamber 65 entrains secondary air 66a, 66b from a room through a circulation air opening 67 into the supply air device 60. The supply air device 60 comprises a filter 68a through which the secondary air 66a, 66b flows when flowing to the mixing chamber 65. In the mixing chamber 65, second part of the secondary air 66b may circulate also to the other side of flows provided by the nozzles 64 through the circulation space 69 between the bottom of the supply air device 60 and the nozzle channel structure 63. The first part of the secondary air 66a may not circulate through the circulation space 69, but is directly entrained. The possibility to flow also to the other side of air flows provided by the nozzles 64 increases the entrainment and therefore the amount of the secondary air 66a, 66b. From the mixing chamber 65, the mixture of primary air 61 and filtered secondary air 66a, 66b flows into the room. Increased amount of secondary air 66a, 66b improves circulation effectiveness which therefore improves removal of impurities from room air, if a filter is used, and/or temperature controlling, heating or cooling, of room air, if the supply air device is equipped with a heat exchanger, for example, heating or cooling coil. The part of image 6 comprising the circulation space 69 between the bottom of the supply air device 60 is also shown enlarged. It is also shown a first alternative filter location 68b for the filter 68a that may be arranged to the circulation air opening 67 and a second alternative filter location 68c for the filter 68a that may be arranged to the mixing chamber 65.
Figure 7 shows a simplified cross-sectional view of a part of a supply air device 70 comprising, two, a first and a second nozzle channel structures according to an example embodiment. Nozzle channel structures 71a, 71b are arranged on top of each other and both nozzle channel structures 71a, 71b comprise own mixing chambers 74a, 74b on top of each other so that there is a separating wall 73 between mixing chambers 74a, 74b. Again these nozzle channel structures 71a, 71b may have any shape, for example, a circular rectangular etc. They may even have different shapes. However, one supply air device may comprise more than two nozzle channel structures one on the other. According to the invention, a cross-section of the at least one duct of the duct system of the nozzle channel structure is however circular or oval.
The first nozzle channel structure 71a is again attached at a distance from the bottom of the supply air device 70 and the second nozzle channel structure 71b is attached at a distance from the separating wall 73 for forming circulation spaces. The supply air device 70 comprises also a filter 76. Primary air may be led into the supply air device 70 via a supply air duct. In the supply air device 70 primary air is led into a supply air chamber 72. From the supply air chamber 72 the primary air is led to the nozzle channel structures 71a, 71b comprising a plurality of air nozzles via one or more supply air openings. From the nozzle channel structure 71a, 71b the primary air is led through air nozzles of the nozzle channel structures 71a, 71b into mixing chambers 74a, 74b of the supply air device 70 as primary air flows 75a, 75b. The primary air flows 75a, 75b blown into the mixing chambers 74a, 74b entrain secondary air 77a, 77b from the room through a circulation air opening into the supply air device 70. Inside the supply air device 70 the secondary air 77a, 77b flow through the filter 76 on its way to the mixing chambers 74a, 74b. At least part of the secondary air 74a, 74b circulates through the circulation space between the first nozzle channel structure 71a and the bottom of the device 70 or the other part through the circulation space between the second nozzle channel structure 71b and the separating wall 73 before they mix with the primary air of primary air flows 75a, 75b in the mixing chambers 74a, 74b. From the mixing chambers 74a, 74b, the mixture of primary air and filtered secondary air flows into the room.
This structure comprising a first and a second nozzle channel structures according to the invention increases the secondary air flow even more by increasing entrainment of the secondary air, thereby enhancing the purification or temperature controlling of air in the room.
Although represented differently in fig. 6 and 7, the nozzles according to the invention are provided as perforations without collars.
Figure 8 shows a simplified supply air device according to an example embodiment. Primary air 81 is led into the supply air device 80 via a supply air duct 82. In the supply air device 80 primary air 81 is led to a nozzle channel structure 83 comprising a plurality of air nozzles 84. In this example embodiment the nozzle channel structure 83 is formed as a continuation part of the supply air duct 82 or as a separate part connected to the supply air duct 82. The nozzle channel structure 83 is, in this example embodiment, formed from a duct having straight shape. From the nozzle channel structure 83 the primary air 81 is led through air nozzles 84 to a mixing chamber 85. The primary air 81 blown into the mixing chamber 85 entrains secondary air 86a, 86b from a room through a circulation air opening 88 into the supply air device 80. In the mixing chamber 85, second part of the secondary air 86b may circulate through the circulation space 87 between the wall of the supply air device 80 and the nozzle channel structure 83. The first part of the secondary air 86a may not circulate through the circulation space 87, but is directly entrained. The primary air 81 may be led to the supply air device 80 via the supply air duct 82 by using a fan or a central ventilation system.
Figure 9 shows a supply air device according to an example embodiment in use. The supply air device 90 is used as a local exhaust ventilation device in this example embodiment. Primary air 91 is led into the supply air device 90. In the supply air device 90 primary air 91 is led to a nozzle channel structure 93 comprising a plurality of air nozzles. From the nozzle channel structure 93 the primary air 91 is led through air nozzles to a mixing chamber 95. The primary air 91 blown into the mixing chamber 95 entrains secondary air 96a, 96b from a room 92 through a circulation air opening 98 into the supply air device 90. In the mixing chamber 95, second part of the secondary air 96b may circulate through the circulation space 97 between the bottom 94 of the supply air device 90 and the nozzle channel structure 93. The first part of the secondary air 96a may not circulate through the circulation space 97, but is directly entrained. In this example embodiment the supply air device 90 is used for removing gases or odours 99 locally.
The local exhaust ventilation device or a supply air device according to an example embodiment may be fixed also to a separate support structure instead of a ceiling or a wall.
It should be noted that it is possible that one or more fans are arranged to provide air directly for a nozzle channel structure according to embodiments of the invention without a supply air ducts.
It is also possible to adjust the blowing direction of primary air of a nozzle channel structure by changing the blowing direction of nozzles. A supply air device may further comprise one or more openings on its sides of its casing, so that primary air that is turned to blow towards the outer walls of the supply air device may be blow out through those openings with secondary air that it has entrained. It is also possible to adjust location of a nozzle channel structure or a part of the nozzle channel structure or one of the nozzle channel structures, when comprising more than one nozzle channel structures in relation to the bottom and/or walls of the supply air device. In other words, location of the nozzle channel structure or a part of the nozzle channel structure inside the supply air device is adjustable.
It should be also noted that it is possible to use the air nozzle structure according to the invention also for other gases than air.
It is obvious that the present invention is not limited solely to the abovepresented embodiments, but it can be modified within the scope of the appended claims.

Claims

A supply air device comprising:
a nozzle channel structure (21) being a duct system comprising at least one duct which comprises a plurality of nozzles (23), a supply air chamber (22), and a mixing chamber (24),

wherein the nozzle channel structure (21) is arranged in a distance from the bottom and a side of the supply air device (20) so that a circulation space (69) is formed between the bottom and the nozzle channel structure (21) and between the side and the nozzle channel structure (21), and wherein the nozzle channel structure (21) comprises one or more supply air openings via which primary air is led to the nozzle channel structure (21) from the supply air chamber (22), further from the nozzle channel structure (21) to the mixing chamber (24) through the plurality of nozzles (23) as primary air flows and wherein said primary air flows entrains secondary air from outside the supply air device (20) to flow to the mixing chamber (24) and wherein a part of said secondary air flows to the mixing chamber (24) through the space between the bottom and the nozzle channel structure (21), characterized in that the plurality of nozzles (23) configured to blow said primary air flows entraining said secondary air are provided as perforations without collars, and wherein a cross-section of the at least one duct is circular or oval.
A supply air device according to claim 1, wherein the primary air is led to the nozzle channel structure (21) from a central ventilation system or by using a separate fan.
A supply air device according to claim 1 or 2, wherein the nozzle channel structure (21) is a peripherally closed duct system.
A supply air device according to claim 1 or 2, wherein the nozzle channel structure (21) comprises at least two separate duct sections or separate ducts.
A supply air device according to claim 1 or 2, wherein the nozzle channel structure (21) is formed from a duct having straight shape.
A supply air device according to any of the previous claims, wherein the supply air device (20) further comprises a filter (36).
A supply air device according to any of the previous claims, wherein the supply air device (20) further comprises a temperature controlling device for cooling or heating the secondary air, wherein the secondary air is led through the temperature controlling device into the mixing chamber (24).
A supply air device according to any of the previous claims, wherein the supply air device comprises two or more nozzle channel structures (71a, 71b) with separate mixing chambers (74a, 74b).
A nozzle channel structure for a supply air device, wherein the nozzle channel structure (21) is a duct system comprising at least one duct which comprises a plurality of nozzles (23) and one or more supply air openings via which primary air is led to the nozzle channel structure (21) and from the nozzle channel structure (21) through the plurality of nozzles as primary air flows and wherein said primary air flows entrains secondary air from outside the supply air device characterized in that the plurality of nozzles (23) configured to blow said primary air flows entraining said secondary air are provided as perforations without collars, and wherein a cross-section of the at least one duct is circular or oval.
A nozzle channel structure according to claim 9, wherein the nozzle channel structure (21) is a peripherally closed duct system.
A nozzle channel structure according to any of the claims 9 or 10, wherein the nozzle channel structure (21) comprises at least two separate duct sections or separate ducts.