FI90466B - Method and distribution device for introducing air into a room - Google Patents

Abstract

A method of introducing air into a room by passing supply air (A) into a distribution device (1) ending in the room (2) and by blowing the air from the distribution device through air supply openings (8, 9) into the room. In order to control the introduction of air even when the supply air is considerably warmer than the room air, the supply air is introduced into the distribution device selectively through two separate independent flow paths (4, 5) into the air supply openings, whereby the supply air is subjected to flow conditions required for heating at the air supply openings (8) of one flow path and correspondingly to flow conditions required for cooling at the air supply openings (9) of the other flow path. A distribution device carrying out the method comprises at least two separate alternative flow ducts (4, 5) for supply air, the flow ducts being provided with separate air supply openings (8, 9) which provide different flow conditions in the separate flow ducts.

Description

1 90466

The present invention relates to a method for introducing air into a room, the method according to which 5 - supply air is led to a room-ending distributor and - is blown from the distributor through supply openings into the room, wherein - supply air is led to the room through at least two separate flow paths to different supply openings, and - the supply air is subjected to different supply conditions at the supply openings of each flow path than at the supply openings of the other flow paths.

15 In order to bring air into the room, a wide range of devices has been developed, which can be roughly divided into three main groups:

With so-called mixing air distributors, air is usually introduced into the upper part of the room from a single point at a rate of up to 20 inches through various slots, nozzles or openings. The air flowing from them draws in and mixes with a large amount of ambient room air. The entire air mass of the room is thus moved and mixed to a homogeneity of almost 25 in terms of both temperature and impurity content.

Due to the high flow rate, annoying noise is easily generated. Large air jets are difficult to control. If the air speed is too high, disturbing traction will occur. If, on the other hand, it is too small, easily dead areas are created in the room 30 where the air does not change. The control of thermal conditions is hampered by the effect of thermal forces despite mixing with the air jet. If the supply air is warmer than the room air, the air jet bends upwards, so that the air at the bottom of the room does not change. If the air is colder, it bends downwards and causes traction. Room temperature control by adjusting the supply air temperature is thus only possible to a limited extent. Also, the airflow cannot be adjusted very much without causing the disadvantages described above.

In the so-called displacing air distribution, air is introduced at low speed directly into the living area via a relatively large surface.

Traction and sound problems are usually avoided if the supply and room air temperatures are the same. If the temperature difference rises to 2-3 degrees, thermal forces begin to control the flow. When the supply air is colder than the room air, the flow "drops", the speed increases due to thermal forces and draft is created at floor level.If the supply air is warmer than the room air 15, it rises Since there is no air jet to draw room air with it, the moving air mass is small and the flow is therefore sensitive to interference.Convection currents, machines moving air, movement of people, various flow obstructions, etc. may control air flows in the room. poor local ventilation.Airflow can be adjusted over a wide area without inconvenience ai-25.

Recently, the so-called active displacement, which eliminates some of the weaknesses of displacing air distribution. The air distribution is spread over a large surface. Air flows into the room from small nozzles at a high speed of 30 d and mobilizes a large mass of air. When the air jet from the small nozzle is small, no noise nuisance occurs despite the high speed. The speed of the air in a small shower decreases quickly, so traction does not occur easily. When a large air mass is in motion, the flow is only affected locally, so that ventilation throughout the room is even. Thanks to the high mixing ratio of the supply and room air, the temperature differences are evened out, so that even cold supply air can be introduced into the oles-5 coil area without "falling" the flow. There is no floor tension with a temperature difference of 15 degrees yet.

However, if the supply air is considerably warmer than the room air, even a small temperature difference after strong mixing will cause the air to rise out of the living area.

The airflow can be adjusted over a wide range. Active displacement is thus very well suited for cooling, but to a limited extent for heating. This method of air distribution is described in FI patent publications 79,608, 15,73,513, 72,800 and 71,417.

The object of the present invention is to provide a method which eliminates the above-mentioned drawbacks and enables the proper operation of active displacement in particular even when the supply air is considerably warmer than room air. The room temperature can then be fully controlled and adjusted. This object is achieved by the method according to the invention, which is characterized in that the supply air is optionally led through one or more separate independent flow paths.

The invention is based on the idea that the supply air is led from the distributor to the room along two different optional flow paths, so that different inflow conditions can be developed for the supply air by means of different inflow nozzles depending on which flow path the air is blown into the room. One flow path can be used in a heating situation and the other in a cooling situation. Where neither heating nor cooling is required, the supply air can be conducted partly along both flow paths.

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The invention is particularly suitable for active displacement, but it can also improve the properties of other air distribution methods.

The invention also relates to an air distribution device for applying the method described above. This air distribution device is characterized in that the distribution device has shut-off means for separating the flow channels from each other, and that each flow channel is formed as an independent air distribution device which operate simultaneously together or separately.

The basic idea of the manifold is that the in-blow openings, for example nozzles, are divided into at least two separate groups to which the supply air can be led through separate flow channels. 15 Thus, the number and orientation of the nozzles, the air flow rate in the nozzles, and even the size and shape of the nozzles may be different in each group. From the same air distribution device, two or more different air distribution systems are thus obtained, the characteristics of which can change almost steplessly from one system to another.

The invention will be explained in more detail below with reference to the accompanying drawing, in which Figs. 1 and 2 show an embodiment of a distribution device according to the invention seen from the side and in section along the line II-II in Fig. 1, Figs. 3A and 3B schematically show air flow from a distributor a background pattern in a room in a cooling situation and a corresponding heating situation, and Fig. 4 shows a second embodiment of the distributor seen from the side.

The air distribution device shown in Figures 1 and 2 of the drawings comprises an elongate inlet pipe 1 connected at its end from a supply air supply system A (not shown) and extending into the air-conditioned room 2. The pipe is mounted horizontally above the living area. The inlet pipe is divided by a central baffle 5 3 into two longitudinal halves which form two mutually isolated flow channels 4 and 5 terminating in a closed end plate 6 of the inlet pipe. The exchange damper-10 ti is pivotable between two extreme positions, in which the exchange damper alternatively completely closes one of the flow channels. The damper can also be set to intermediate positions where both flow channels are partially open. It is essential that the flow control direction of the upper flow channel 15 and the lower flow channel of the inlet pipe is opposite, i.e. when the flow of the second channel closes, the flow of the second channel opens. The damper can be manually operated or connected to a suitable control device.

A large number of nozzles 8 are mounted on the jacket surface of the upper flow channel 4 of the inlet pipe, which direct the supply air radially into the room. Numerous nozzles 9 are also mounted on the jacket surface of the lower flow channel, which are also radial. The nozzles of the upper ka-25 hub have smaller flow openings than the nozzles of the lower channel.

Figures 1 and 2 show the operation of the distributor in a cooling situation, i.e. when the supply air A is colder than the room air. In this case, the exchange damper 7 is turned 30 to close the lower flow channel 5, so that the supply air flows into the room only through the nozzles 8 of the upper flow channel 4.

Figure 3A schematically shows a flow pattern generated in a room in a cooling situation. The air jets B emanating from the upper nozzles 8 of the inlet pipe 35 are directed upwards and to the sides and are drawn from below from the so-called induction air and mix with it. Because the air in the showers is colder than the environment and therefore heavier, the showers tend to bend downwards. Below the inlet pipe there is a small vacuum due to the jets, which tends to bend the downwardly directed flow, which no longer has temperature and density differences, to the side and back upwards. The forces acting in different directions create a double vortex flow according to Fig. 3A, in which the main flow direction in the middle is upwards and at the edges downwards. Although the flow rates are very low, they can be experimentally demonstrated. Like forced vortex currents in general, the vortex is very stable relative to the magnitude of the pulse that generated it, and pa-15 recovers very quickly to its original form after a disturbance.

The distributor still works as described above, even when the supply air is slightly warmer than the room air. In equilibrium, the vacuum below the inlet pipe is equal to the thermal lift caused by the density difference. If the temperature difference increases, the flow bends upwards and the supply air no longer enters the living area. The situation is complex, as the stability of the vortices decreases as the temperature difference decreases. In this case, even a small disturbance, flow obstruction, etc. may completely change the nature of the flows.

When the supply air is warmer than the room air, the replacement damper 7 is turned to the position shown in broken lines in Fig. 1. In this case, the supply air supply to the upper flow duct 4 is prevented and the supply air flows into the room only from the nozzles 9 of the lower flow duct 5. The air jets C are directed downwards and draw room air from above the inlet pipe. Thermal forces bend the jets upwards. If the flow pulse is appropriately selected, the flow pattern shown in Figure 3B is formed.

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If the nozzles 8 and 9 of both flow channels are similar, the impulse can only be influenced by changing the number of nozzles 9 of the lower channel, whereby the flow rate in them also changes. In order for the warm air 5 to reach the residence area, the impulse and flow rate in the nozzles 9 must generally be clearly higher than in the upper duct nozzles 8, i.e. the lower nozzles 9 must have fewer than the upper nozzles 8. In the air distributor 10 of Fig. 1, preferably also in their orientation. As the number decreases, the Circular Sector, which has nozzles, shrinks and the showers are directed more and more centrally downwards.

However, the flow rate in the lower channel nozzles 9 cannot be increased without restrictions: the pressure drop or the sound level easily becomes too high. This problem can also be solved in the system according to the invention by choosing the nozzles 9 to be of a different type than the nozzles 8, so that the impulse of the nozzles 9 and in particular 20 ns. throw length is greater than nozzle 8.

For reasons of manufacturing, among other things, it may be advantageous to keep the nozzles 8 and 9 similar. The flow can be made to the desired type by adding a few large nozzles to the nozzles 9 of the lower channel, which then act as carrier jets and take the air into the living area. Such a solution is also advantageous in that the mixing ratio of the supply and room air remains high.

If the nozzles 9 of the lower duct have to be dimensioned for high heating power and thus for a large temperature difference which must be adjusted from zero to maximum power, the flow from the nozzles 9 may be too strong and cause draft in the residence area when the temperature difference is small. The dispensing device is then made to function properly 35 by discharging a smaller part of the air 8 90466 by means of an exchange damper 7 through the nozzles 8 of the upper duct.

The air flow and thus also the velocity in the nozzles 9 of the lower channel decreases, whereby the pulse and throw length of the air jet im-5 also decrease. In addition, the slow-flowing supply air from the nozzles 8, drawn by the air jet of the nozzles 9, becomes its mixing air, whereby the temperature of the air in the jet rises and the thermal buoyancy tends to slow down the downward jet 10 more strongly. In addition, the flow from the nozzles 8 in the opposite direction slows down the flow from the nozzles 9 and thus reduces the pulse and throw length of the jet. In this way, the flow field can always be modified in such a way that the supply air flushes the entire residence-15 area without causing harmful draft.

The embodiment of the distribution device shown in Fig. 4 differs from the above only in that the closing means of the different flow channels 4, 5 of the inlet pipe 1 is a so-called butterfly damper 10. This damper comprises two semicircular plates fixedly perpendicular to each other, which are pivotally mounted on a spacer plate perpendicular to it. The damper 10 operates in the same way as the replacement damper 7 described above.

The drawings and the related description are intended only to illustrate the idea of the invention. The details of the method and dispenser of the invention may vary within the scope of the claims. The inlet pipe of the distributor can also be rectangular, oval, etc. in cross-section, and the length to diameter ratio 30 may vary. The spacer may be angular, curved, etc. It also need not be parallel to the centerline of the tube or the sides of the rectangular tube in the longitudinal direction. The tubes are drawn straight, but it can also be conical and may have shrink pieces 35, etc. The replacement damper can be, for example, a guide wing 9 9 Π A 6 6 din. The inlet openings of the inlet pipe may be mere openings or holes or the like instead of nozzles.

Instead of a swiveling damper, a solution with a guide plate 5 fixedly connected to the spacer plate 3 can be used. The spacer is mounted so that it rotates around the center line of the tube 1. By turning the baffle 180 degrees, the supply air can be directed to either the nozzles 8 or 9. The disadvantage of this solution is that the air cannot be partially directed to the nozzles 8 and 9 without substantially changing the direction of the air jets and the flow field generated by them. Bearing of large-sized spacers, often several meters long, is difficult and becomes considerably more expensive than the simple sheet metal 7 according to Figure 1. The shape of the pipe 1 is also limited.

15 If the spacer 3 is an arc of a circle with a radius slightly smaller than that of the tube 1 and pivots about the center line of the tube, it forms a barrier plate which can be pivoted to close either the nozzles 8 or 9. The weaknesses are the same as in the application described above. The advantage is a lower pressure drop because air flows to the nozzles through the entire cross-section of the pipe 1.

The spacer 3 can also be made fixed and the tube 1 rotated around it. In this and the previous application, the spacer plate can also be outside the tube 1 25.

Claims (9)

A method for introducing air into a room, the method comprising: 5. supplying air (A) to a manifold (1) terminating in the room (2) and - blowing from the manifold through the air inlets (8,9) into the room, wherein - supply air (A) is introduced in the manifold (1) at least 10 via two separate flow paths (4,5) to different supply openings (8,9), and - the supply air is subjected to different supply conditions (B, C) at the supply openings (8, 9) of each flow path than from the supply openings of the other flow paths. characterized in that the supply air (A) is optionally led through one or more separate independent flow paths (4,5). Method according to Claim 1, characterized in that the supply air (A) is optionally conducted in the heating situation and in the cooling situation via different flow paths (4.5). Method according to Claim 1, characterized in that the supply air (A) is led partly along both flow paths (4,5) when no heating or cooling is required. A distributor for introducing air into a room, which and the collector (1) can be connected to a pipe for supply air (A) and are provided with openings (8,9) for blowing supply air into the room (2), the distributor (1) having at least 30 separate flow channels (4,5) for the supply air (A), wherein the different flow channels (4,5) are provided with their own supply air openings (8,9), and the supply air openings (8,9) are adapted to provide the flow through the different flow channels (4,5). different supply air conditions (B, C) for the supply air, characterized in that in the distributor I! 11 9 Ο Λ ή 6 are closing means (7; 10) for separating the flow channels (4,5) from each other, and that each flow channel is formed as an independent air distribution device operating simultaneously together or separately. A manifold (1) according to claim 4, formed by a tube, characterized in that the manifold (1) is divided by an axial partition (3) into two longitudinal flow channels (4,5) and in that the inlet end of the partition has a shut-off flap (9); 10), which 10 is pivotable from the supply air (A) of one of the flow channels to the closing position. Dispensing device according to Claim 5, characterized in that the position of the shut-off flap (9; 10) is adjustable between the closing positions 15 of each flow channel (4,5). Dispensing device according to one of Claims 4 to 6, in which the inflow openings (8, 9) are formed by nozzles, characterized in that the nozzles (8, 9) belonging to different flow channels (4,5) have different sizes and / or numbers. different sorts of. Dispensing device according to one of Claims 4 to 7, characterized in that the nozzles (8, 9) belonging to the different flow channels (4.5) are substantially opposite. i2 9 P 4 6 6