EP0993555A1

EP0993555A1 - Apparatus for conditioning air

Info

Publication number: EP0993555A1
Application number: EP98932618A
Authority: EP
Inventors: Guennadi Anatolievich Nesterov
Original assignee: Inalfa Industries BV
Current assignee: Inalfa Industries BV
Priority date: 1997-07-02
Filing date: 1998-07-02
Publication date: 2000-04-19
Anticipated expiration: 2018-07-02
Also published as: AU8245598A; NL1006451C2; WO1999001669A1; DE69821484D1; DE69821484T2; EP0993555B1

Abstract

An apparatus for conditioning air comprises a casing (1) provided with an air flow channel (4) and with a fan comprising a drive unit (11), which is mounted in said channel (4). Humidifying means are fitted with a number of humidifying elements (13) which rotate about a shaft (9), partially within said air channel (4) and partially in water supply means (8). The fan is provided with air flow elements (12), which rotate independently of said humidifying elements (13). The humidifying elements (13) and the air flow elements (12) are disposed at least approximately concentrically or coaxially with respect to each other, preferably near the air flow elements (12) and within the sphere of action thereof. The air flow elements (12) are for example disposed internally of the annular humidifying elements.

Description

Apparatus for conditioning air

The present invention relates to an apparatus in accordance with the preamble of claim 1.

Such an apparatus is for example used as an apparatus for humidifying, cleaning and/or cooling air, and so far applications in homes or offices as well as industrial applications have become known. Examples of such apparatus can be found in DE-A-1 778 268, EP-A-0 118 811 and DE-A-32 43 080. With these apparatus, air is carried from the fan to the humidifying means, which may for example be parallel discs. The fan and the humidifying means may each comprise their own drive unit, but it has also been proposed to use the fan drive unit for the humidifying means as well, for example via friction wheels (EP-A-0 118 811) or by fitting the humidifying means with an impeller wheel, which can be driven by an external air flow (DE-A-1 778 268) .

Nevertheless, the humidifying means and the fan together still take up a large amount of space, which is unacceptable in some applications.

In DE-A-25 23 199 it is proposed to use the same discs both for generating an air flow and for humidifying said air flow. It will be apparent, however, that said apparatus cannot function well, since the demands which are made of the fan discs are quite different from those which are made on the discs which must function as humidifying means. The fan discs, for example, would have to rotate much faster than the discs of the humidifying means.

The object of the invention is to provide an apparatus of the kind referred to in the introduction, wherein the drawbacks mentioned have been eliminated in an effective manner.

To this end the apparatus according to the invention is characterized by the aspects as stated in the characterizing portion of claim 1. Advantageous embodiments of the invention are the subject matter of the subclaims. Since the fan and the humidifying means are combined by overlapping each other and/or by being incorporated into each other to form one unit, and since they are disposed concentrically, for example, it is possible to realise a very compact arrangement which preferably comprises only one shaft, so that the apparatus can be made considerably smaller than the known apparatus, which comprise separately fitted humidifying elements and air flow elements. Since the humidifying means and the air flow elements may consist of separate parts and are capable of rotating independently of each other, however, they can each be given the desired properties, so that a properly functioning apparatus of small dimensions can be obtained. The at least approximately concentric or coaxial arrangement of the air flow elements and the humidifying means furthermore makes it possible to arrange for the humidifying means to be driven by the air flow elements if the humidifying means are disposed near and within the sphere of action of the air flow elements. Another major additional advantage of this embodiment besides its compact construction is the fact that a separate drive unit for the humidifying means or a transmission between the fan and the humidifying means are not required. In this embodiment the humidifying means can be driven by the air flow generated by the air flow elements, whereby the air flow elements and the humidifying means are preferably constructed in such a manner that said drive takes place almost automatically, without any additional parts being required. A embodiment which is advantageous from the viewpoint of flow is one wherein the air flow elements are disposed internally of the annular humidifying means. In this way outside air is generally carried first through the humidifying means, then through the flow elements, and preferably through the humidifying means again, as a result of which a very good humidification of the air can take place. An advantageous embodiment is one wherein the air flow elements are substantially parallel discs which are mounted on a shaft, whilst the humidifying means may be substantially parallel annular discs. This embodiment provides an apparatus which exhibits a relatively low energy consumption, a very low noise level and an efficient operation.

Further aspects of the invention are defined in other independent claims . The invention will be explained in more detail hereafter with reference to the drawings, which show an embodiment of the apparatus according to the invention.

Fig. 1 is a vertical sectional view of the apparatus according to the invention. Fig. 2 is a sectional view along line II-II in Fig.

1, which shows part of the apparatus.

The drawing shows an embodiment of an apparatus for conditioning air, which could be used as an independent unit, for example for cleaning and humidifying air in a space such as a room, a cabin or the like, so as to enhance the level of comfort therein. On the other hand it is possible to incorporate the apparatus into a larger plant, for example into an air conditioning plant which operates according to the absorption or adsorption principle, wherein dry, relatively hot air is to be cooled and humidified by causing water to evaporate therein. Such an air conditioning plant could be used in means of transport such as trucks, caravans and passenger cars, and in particular in the latter case it is highly important that a silent and small apparatus exhibiting a low energy consumption is provided.

According to Figs. 1 and 2, the apparatus comprises a casing 1, which is closed but for an air inlet 2 and an air outlet 3. An air flow channel 4 extends from air inlet 2 to air outlet 3 , which air flow channel is bounded laterally by side walls 5 of the casing, by a boundary wall 6 on the upper side and by partitions or plates 7 bounding the upper side of a water bath in casing 1 on the bottom side. Said water bath 8 contains the water which is to be absorbed as water vapour by the air flow through the air flow channel.

Disposed in the air flow channel 4 is a horizontal shaft 9, which is rotatably supported in the casing at its ends by means of bearings 10. A drive unit, such as an electric motor or the like, engages said shaft 9 so as to rotate it . In order to provide a maximally compact apparatus, shaft 9 is made at least partially hollow, and an electric driving motor 11 is mounted within said hollow shaft 9. A number of discs 12, which function as air flow elements, are fixedly mounted on shaft 9 in parallel and preferably evenly spaced relationship. Said discs 12, which must be designed to have a minimum weight and which may for example be made from a plastic, such as PVC, polyethylene, polypropylene and the like, or from aluminium, paper, etc., function to generate an air flow through the air flow channel 4 from inlet 2 to outlet 3. In order to accomplish this, shaft 9 is rotated in such a direction that the discs present in the area adjacent to the water in water bath 8 move from inlet 2 to outlet 3. The discs 12 are preferably designed to have a minimum thickness, and their surface is preferably smooth in order to obtain a low noise level .

Mounted on shaft 9, concentrically with discs 12, are furthermore annular discs 13 operating as humidifying means, which discs 13 are kept in fixed spaced-apart relationship by means of cross pins 14, and which are supported in bearings with respect to casing 1 and shaft 9 via outer connecting elements 15. Annular discs 13 can rotate freely with respect to shaft 9, therefore. The annular discs 13 may for example be supported in bearings on a fixed shaft 16 via connecting elements 15, which fixed shaft 16 functions to support the electric motor and which extends through the hollow shaft 9. It will be understood that various other constructions are also conceivable. The internal diameter of the annular discs 13 is such that said discs surround fan discs 12 with a small clearance of for example 1 - 2 mm, whilst the water level in the water bath is such that the annular discs 13 are completely submerged in the water at their lowest point and can be wetted over their entire surface area, therefore, so that the annular discs 13 can function as humidifying means . The annular discs 13 do not comprise their own drive unit, they are driven by the air flow which is generated by the discs 12. This effect is achieved in that both the incoming air and the outgoing air flow along the annular discs 13 at an angle with the radial, whereby the circumferential components have the same direction of rotation, so that discs 13 are rotated by said circumferential components of the air flow. The rotational speed of the humidifying discs 13 may be substantially lower than that of fan discs 12, for example 30 - 90 rpm for the humidifying discs 13 versus 2000 - 4000 rpm of the fan discs 12. The rotational speed imparted to discs 13 depends on a number of factors, but in principle it is possible to control said speed by having a controllable brake engaging discs 13 so as to vary the counterpressure if this should be necessary in order to obtain a higher or a lower speed of discs 13 relative to discs 12, for example in order to control the relative air humidity or to adapt the amount of air flowing through.

The distribution of discs 12 per unit length is preferably different from that of discs 13, whereby it is preferred to provide more discs 13 per unit length than discs 12. Measurements have shown that a ratio of two to four, preferably three, discs 13 for each disc 12 is advantageous. The radial dimension of the discs between the inside and the outside diameter is preferably about 25 - 50% of the radius or radial dimension of the discs 12. The surface of discs 13 may be smooth but also slightly absorbent, and may be provided with holes or other perforations. The surface may be purposely roughened or be given a specified surface structure so as to obtain a larger air delivery or a greater pressure drop, which is in essence caused by microturbulence . The diameter of the air outlet 3 is considerably smaller than that of inlet 2, with the ratio for example being 1 : 3 - 4, preferably 1 : 3. The outlet 3 is preferably positioned in line with the lower half of discs 12, and the bottom edge of air outlet 3 is approximately in line with the lower tangent point of discs 12. Air flow channel 4 does not necessarily have to be straight at air outlet 3, also other configurations are possible, of course. The operation of the above-described apparatus is as follows.

When electric motor 11 is energized, shaft 9 will be driven to rotate at a predetermined, possibly controllable speed of a few thousand revolutions per minute and, due to the shape of the air flow channel, an air flow will take place on one side, on the bottom side of shaft 9 in the illustrated case, as a result of the friction of discs 12 along the air, as a result of which the air is carried along and flung outside at outlet 3, where the air channel is not bounded by casing 1 or by the water in water bath 8. The flowing in and the flowing out of air to and from the discs 12 mainly takes place in a non-radial manner, as a result of which the generated air flow exerts a driving force on the freely rotating annular discs 13, which concentrically surround discs 12. Said annular discs 13 run through the water of a water bath 8 on their lower side, as a result of which they are wetted, whereby the moisture can be absorbed by the air flow, thus increasing the air humidity level . Heat of vaporization will be withdrawn from the air as a result of the evaporation of the water, thus causing the temperature of the air to decrease, so that the apparatus also functions as a cooling apparatus. Furthermore, dust and other contaminations will adhere to the wet surface of discs 13, so that the apparatus also has a cleaning function. Since the discs 13 run through the water bath 8, the contaminations can be removed there, so that the discs 13 will remain clean. Since a large number of discs 13 are provided per unit length, a large humidifying area is available and a high degree of humidification can be achieved. This degree of humidification of the air can be controlled, for example by controlling the number of revolutions of the humidifying means and/or of the air flow means of the fan. The energy consumption is quite low thereby. Thus it is possible to achieve an air displacement of 300 m³/h with an electric motor of 20 - 30 W. The noise level of this disc fan is very low. A level of less than 30 dB is attainable without any problem. If the apparatus according to the invention is incorporated in a longer air flow channel comprising other units, the apparatus may even act as a sound damper if it is mounted at the outlet end of the channel. Since the evaporation of the water takes place at the surface of the humidifying means and not in the air itself, as is the case with spraying, no drops are formed, which is comfortable and healthy.

The invention is not limited to the embodiment illustrated in the drawing and described above, which can be varied in several ways within the scope of the invention. Thus it is possible to provide the humidifying means internally of the air flow elements. In that case humidification must take place in a different manner, of course, for example from the inside through the hollow shaft . The humidifying means and the air flow means can also be mounted on parallel shafts, or on intersecting shafts, preferably provided they are integrated with each other. Instead of using water, it is also possible to use another suitable liquid, of course, whilst the water may furthermore contain additives, such as antifreeze and/or aromatic substances. Furthermore, the fan may comprise air flow elements other than discs, for example blades or the like, and may also be positioned outside the casing and may be used for other purposes too. With a proper design of the humidifyer it can be driven by the air flow of the fan, possibly with variable speed.

According to a further aspect of the invention, both the air flow means and the humidifying means may be constructed as discs which are housed in a common casing and rotate about parallel shafts, but which do not overlap. The air flow means and the humidifying means may have their own drive or the drive of one may be branched off from the other through a variable transmission or coupling, so that both means may rotate with an optimal rotational speed which may vary in an absolute and relative sense depending on the circumstances .

Claims

1. An apparatus for conditioning air comprising a casing (1) provided with an air flow channel (4) , a fan comprising a drive unit (11) , which is mounted in said channel, and humidifying means fitted with a number of humidifying elements which rotate about a shaft (9) , partially within said air channel and partially in water supply means (8) , characterized in that said fan is provided with air flow elements (12) which partially overlap said humidifying elements (13), and which rotate around or within said humidifying elements, albeit independently thereof.

2. An apparatus according to claim 1, wherein said humidifying elements (13) and said air flow elements (12) are disposed at least approximately concentrically or coaxially with respect to each other.

3. An apparatus according to claim 1 or 2 , wherein said humidifying elements (13) are mounted near the air flow elements (12), within the sphere of action thereof.

4. An apparatus according to claim 3 , wherein said air flow elements (12) are disposed internally of the annular humidifying elements (13) .

5. An apparatus according to any one of the preceding claims, wherein said air flow elements (12) are configured as substantially parallel discs which are mounted on a preferably horizontal shaft (9) .

6. An apparatus according to claim 4 or 5, wherein said humidifying elements (13) are configured as substantially parallel annular discs, and/or wherein said humidifying elements (13) are provided with channels extending from the outside towards the inside, for example in the form of a honeycomb structure.

7. An apparatus according to claims 5 and 6, wherein said humidifying discs (13) are provided in a greater number per unit length than the air discs (12) .

8. An apparatus according to any one of the preceding claims, wherein said water supply means comprise a water bath, and wherein said air channel (4) preferably extends adjacently to the water bath, under said shaft (9) .

9. An apparatus according to any one of the preceding claims, wherein the diameter of said air channel (4) is larger on the inlet side (2) than on the outlet side (3) .

10. An apparatus according to claims 8 and 9, wherein the circumference of said air flow elements (12) and said humidifying elements (13) are surrounded on the side remote from the water bath (8) by a closely adjoining wall (6) , whilst the water bath (8) is preferably covered by a cover (7) in places outside the humidifying elements, which cover will also bound the air flow channel (4) in that case.

11. An apparatus according to any one of the preceding claims, wherein said shaft (9) is hollow, and wherein an electric motor (11) for driving the shaft (9) is housed within said shaft .

12. An apparatus according to any one of the preceding claims, wherein a control element is provided for controlling the humidifying function, for example by controlling the number of revolutions of the fan and/or of the humidifying means, wherein the control element for the humidifying means may be provided with a controllable brake, which engages the humidifying elements (13) .

13. An apparatus for conditioning air, comprising a casing (1) provided with an air flow channel (4) , a fan comprising a drive unit (11) , which is mounted in said channel, and humidifying means fitted with a number of humidifying elements which rotate about a shaft (9) , partially within said air channel and partially in water supply means (8) , characterized in that, both the air flow elements (12) and the humidifying elements are constructed as substantially parallell discs mounted on a shaft (9) .

14. An apparatus according to claim 13, wherein the discs of the air flow elements and the discs of the humidifying elements rotate about their own parallel shafts.

15. An apparatus according to claim 13 or 14, wherein the air flow elements and the humidifying elements comprise there own drive or comprise a coupled drive having a variable transmission.

16. An apparatus for conditioning air comprising a casing (1) provided with an air flow channel (4) , a fan comprising a drive unit (11) , which is mounted in said channel, and humidifying means fitted with a number of humidifying elements which rotate about a shaft (9) , partially within said air channel and partially in water supply means (8.

17. An apparatus for conditioning air, comprising a casing (1) provided with an air flow channel (4) and humidifying means fitted with a number of humidifying elements which rotate about a shaft (9) , partially within said air channel and partially in water supply means (8) and having the shape of substantially parallel discs, which are driven by air flowing through the channel .