Such a valve is known from practice. Through operation, the valve body can be brought into the first or second valve position, in order that a desired fluid flow can take place between the first or second channel on the one hand and the third channel on the other hand. Operation of the valve body can take place in different ways, for instance by means of an operating mechanism connected to the valve body, with which operation can be carried out manually and/or automatically. When such a valve is applied in a ventilation system of a vehicle, the first channel may be intended, for instance, for air supply from an environment, the second channel for air supply from a passenger space of the vehicle, and the third channel for air supply to this passenger space. In that case, when the valve body is in the first valve position, fresh air can be supplied from the environment to the passenger space via the above-mentioned fluid communication between the first and the third channel, while air in the vehicle can be recirculated when the valve is in the second valve position, in which the second channel has been placed into communication with the third channel.

It is a disadvantage of the known two-way valve that it can produce relatively much noise when a fluid flows via the channels along the valve, in particular at relatively high fluid flow rates. This is a nuisance to persons present in an environment and may thus lead to annoyance, experieced, for instance, by persons present in a vehicle provided with a ventilation system having such a noise-producing valve. In the latter case, a large amount of aerodynamic noise produced by the valve can deteriorate an acoustic

climate in the vehicle, which may, for instance, disturb a conversation of occupants of the vehicle.

Particularly disadvantageous is the known two-way valve when a fan is arranged downstream of the valve, which is common, for instance, in a vehicle ventilation system. In that case, the amount of aerodynamic noise produced by the fan has been found to depend typically on the amount of noise produced by the two-way valve, which can lead to a considerable total amount of noise produced by the valve and the fan. The invention has for its object to remove the disadvantages of the two-way valve of the type described in the opening paragraph, while retaining the advantages thereof.

In particular, the invention has for its object to provide a low-noise two-way valve.

To this end, the two-way valve according to the invention is characterized in that the valve body is arranged to form a substantially gradual connection between a wall of the first and second channel, respectively, and a wall of the third channel when the valve body is in the first and the second valve position, respectively.

When the valve body is in the first valve position, the body forms a substantially gradual connection between the wall of the first channel and the wall of the third channel while these channels have been placed into fluid communication with each other. As a result, fluid can flow between these two channels with relatively little noise being produced in the two- way valve, since the connection established by the valve is substantially gradual. When the valve body is in the second valve position, the same is achieved for a fluid flow between the second and the third channel.

The wording'a substantially gradual connection'may be understood to mean, for instance, a smooth connection where parts of the valve body extending along the flowing fluid include substantially no large kinks, relatively abrupt bends, large angles, projections extending into the flowing fluid, relatively large openings, or the like. In addition, this wording

encompasses a connection such that areas of contact and attachment of the valve body with/to the walls of the channels have a substantially smooth configuration, with the valve body linking up substantially smoothly with a wall of the channels.

The use of the two-way valve provided by the invention is particularly advantageous when downstream of the valve a fan is arranged.

Since this valve, during use, produces relatively little noise, the fan will produce relatively little noise, at least in the case where such noise depends on the noise produced by the valve. It has been found, accordingly, that by using this valve in combination with a fan placed downstream thereof, a substantial reduction of aerodynamic noise produced by this fan can be achieved, compared to the use of the above-mentioned two-way valve known from practice in combination with a fan placed downstream thereof.

An additional advantage of the two-way valve according to the invention is that the use of this valve is favorable from a viewpoint of efficiency of a fluid pump connected to the channels, such as a fan. This is because the present valve body can constitute a relatively small flow resistance between the channels due to the above-mentioned substantially gradual connection. Accordingly, of the pumping power exerted by the fluid pump on a fluid to be pumped through the channels, relatively little is lost under the influence of the resistance of this valve body.

According to a first preferred embodiment of the invention, the valve body is arranged to change during operation from a first to a second valve shape, and vice versa, which first and second valve shape, respectively, is such that the valve body in the first and the second valve position, respectively, forms a substantially gradual connection between the first and the second channel, respectively, and the third channel.

This valve body may be of relatively simple and inexpensive design and, for instance, be fitted between the channels to control the fluid flow.

Preferably, the valve body is at least partly made of flexible material for the purpose of the change in valve shape.

Thus, the valve body can be made of a substantially rigid material at a free end, while the remaining part of the valve body is made substantially of flexible material. Also, the valve body may be made substantially completely of flexible material, so that an excellent gradual connection can be obtained. Further, the valve body may, conversely, be made substantially of flexible material at a free end, while the remaining part of the valve body is made substantially of a rigid material.

The valve body may further comprise at least two valve body segments movably, in particular hingedly or pivotally, joined together for the purpose of obtaining the above change of shape. Thus, the valve body may, for instance, comprise a number of plate-shaped plastic elements interconnected with film hinges.

According to a further elaboration of the invention, the valve body is bistable, such that it can toggle from one valve shape to the other.

A bistable valve body can easily toggle from one valve shape to the other. Thus, the bistable body may be designed as a body of which the first valve shape is a substantially concave and convex shape, respectively, when the valve body is in the first valve position and viewed from the first and the second channel, respectively, while the second valve shape is a substantially convex and concave shape, respectively, when the valve body is in the second valve position and viewed from the first and the second channel, respectively.

Preferably, the valve body is hingedly connected to a channel wall located opposite the third channel, so that the valve body can be easily moved from one valve position to the other through a hinging movement.

Specifically in that case, it is advantageous when the valve body is arranged to cooperate, during operation, with the wall of the third channel for the purpose of changing the valve body from one valve shape to the other.

Through the cooperation with the wall of the third channel, the valve shape of the valve body can be easily changed to obtain the right valve shape. An additional advantage is that the valve can thus be designed with relatively few component parts.

According to a further elaboration, the valve is provided with electromagnetic means arranged to change the valve shape of the valve body by exerting an electromagnetic force on the valve body.

Electromagnetic means are easily operable and typically less susceptible to wear than mechanical operating means. Use can be made of, for instance, one or more electromagnets and/or fixed magnets. The valve body can be made, for instance, of a magnetic material and/or a suitable metal. Besides electromagnetic means, the valve may for instance be provided with other means to adjust the valve shape, such as a pneumatic operating mechanism.

According to an alternative embodiment of the invention, the valve body is designed as a valve body operatively rotatable about a rotation axis from one valve position to the other, the valve body being shaped such that the valve body in the first and second valve position, respectively, forms the substantially gradual connection between the walls of the first and the second channel, respectively, and the third channel.

This embodiment of the invention advantageously provides a low- noise two-way valve where the valve body is rotated between the first and the second valve position. The valve body may, for instance, comprise a substantially solid body having the shape mentioned. Further, the valve body may be, for instance, of substantially spherical design and be provided with at least one passage, which passage connects the first and second channel, respectively, and the third channel with each other when the valve body is in the first and second valve position, respectively, the passage extending through the valve body such that the passage forms a gradual connection between the channels.

According to a highly advantageous elaboration of the invention, the valve body in the first and/or second valve position is shaped such that a fluid channel part bounded at least by the valve body has a substantially constant diameter.

Owing to the fluid channel part having a substantially constant diameter and the valve body forming a substantially gradual connection between the channel walls, a fluid can flow through the fluid channel part while producing very little noise. For the purpose of the substantially constant diameter of the fluid channel part, the first and/or second channel may have substantially the same diameter as the third channel.

Preferably, the first, second and/or third channel is provided with a fluid pump, in particular a low-noise centrifugal fan.

With the fluid pump, a fluid flow can be effected in the first, second and/or third channel and channels connected thereto. Specifically the use of a low-noise centrifugal fan as described in Dutch patent application NL 1017423 is advantageous when the fluid comprises a gas or gas mixture, such as air, since through the combination of such a fan and the two-way valve according to the present invention a very low-noise gas flow can be achieved.

Furthermore, the invention provides a ventilation system of a vehicle, provided with a two-way valve according to any one of claims 1-19. By using this two-way valve in the ventilation system, the vehicle can be ventilated by the system while this can give rise to only very little disturbing, unpleasant valve noise of the two-way valve. If the system is provided with a fan placed downstream of this valve, the fan too can only produce relatively little aerodynamic noise during use.

The invention will be described in more detail with reference to a number of exemplary embodiments and the drawing. In the drawing: Fig. 1 shows a cross-section of a first exemplary embodiment of the invention, with the valve body in a first valve position;

Fig. 2 shows a similar cross-section to Fig. 1, with the valve body in an intermediate position; Fig. 3 shows a similar cross-section to Fig. 1, with the valve body in a second valve position; Fig. 4 shows a detail Q of the cross-section shown in Fig. 3; Fig. 5 shows a cross-section of a second exemplary embodiment of the invention, with the valve body in the first valve position; Fig. 6 shows a similar cross-section to Fig. 5, with the valve body in the second valve position; Fig. 7 shows a cross-section of a third exemplary embodiment of the invention, with the valve body in a first valve position; Fig. 8 shows a similar cross-section to Fig. 7, with the valve body in a second valve position; and Fig. 9 shows an assembly of a two-way valve and a centrifugal fan.

Figs. 1-4 show a two-way valve for placing a first channel 1 and a second channel 2, respectively, into communication with a third channel 6.

The valve and the channels 1,2, 6 are shown in cross-section. The first and the second channel 1 and 2, respectively, are each provided with a curved lower wall part 8 and 9, respectively, which merges into a wall 10 of the third channel 6. The curved lower wall parts 8,9 form fixed, gradual connections between the walls of the channels 1,2, 6. Opposite upper wall parts 7 and 3 of the first and the second channel, respectively, merge into each other. The valve is provided with an operable valve body 4, which is hinged to a hinge point 5 located between the upper wall parts 3,7 and opposite the third channel 6. The valve body 4 is made of flexible material, for instance of flexible plastic, rubber, or the like.

Fig. 1 shows the valve body 4 in a first valve position 4a, in which it places the first channel 1 into fluid communication with the third channel 6.

In this position, the flexible valve body 4 is bent so as to form a substantially gradual connection between the wall 7 of the first channel 1

and the wall 10 of the third channel 6. Through operation, the valve body 4 can be pivoted from the first position 4a to an intermediate valve position 4b shown in Fig. 2. In this position 4b, the valve body is substantially unbent.

By subsequently pivoting the valve body 4 further, it can assume the third valve position 4c shown in Fig. 3, in which it is bent so as to form a substantially gradual connection between the wall 3 of the second channel 2 and the wall 10 of the third channel 6. Owing to the substantially gradual connection, which in the present exemplary embodiment is formed by both the fixed lower wall parts 8,9 and the movable valve body 4, this valve is relatively low-noise during use. Preferably, the edges of the valve body 4 link up with the walls of the channels 1,2, 6 in a substantially fluid-tight manner when the valve body 4 is in the first and second valve position 4a, 4c, respectively, so that the second channel 2 and the first channel 1, respectively, can be closed by the valve body 4 in a substantially fluid-tight manner with the body 4 in the first and second valve position 4a, 4c, respectively.

Operation of the valve body 4 may take place, for instance, through operating means not shown. These means may comprise an operating mechanism with or without an operating motor. The operation may further be carried out with, for instance, electromagnetic means.

During operation, the valve body 4 cooperates with the walls, so that the valve body obtains the desired shape. This is shown in more detail in Fig. 4. Through operation, the valve body 4 is pressed against the wall 10 of the third channel 6, which results in a bending of the valve body until the body has obtained the second valve shape 4c.

In the second exemplary embodiment shown in Figs. 5 and 6, the valve body 4 is arranged between the channels 1, 2,6 so as to be rotatable about a rotation axis R. The rotation axis R runs along a center line of the third channel 6. The valve body 4 can therefore be rotated from one valve position to the other valve position 4a, 4c. The valve body is shaped such

that the valve body in the first and second valve position, respectively, forms the substantially gradual connection between the walls 7,3 of the first channel 1 and the second channel 2, respectively, and the third channel 6. In this embodiment, the valve body 4 may be made of, for instance, a relatively strong, rigid material.

Figs. 7 and 8 show a third exemplary embodiment, provided with a spherical valve body 14 arranged between the first channel 1, the second channel 2 and third channel 6 so as to be rotatable about a rotation axis P.

This rotation axis P is at right angles to the plane of the channels 1,2, 6 and intersects a center of the valve body 14. The valve body 14 is provided with a passage 15 connecting the first channel 1 and the third channel 6 when the valve body 14 in the first valve position 14a shown in Fig. 7.

Through operation, the valve body 14 can be rotated to a second valve position 14c shown in Fig. 8, in which the passage 15 connects the second channel 2 with the third channel 6. The passage 15 extends through the valve body 14, such that the passage 15 forms a substantially gradual connection between the channels 1,2, 6, thus providing a low-noise connection between the channels 1,2, 6.

With the valve shown in each exemplary embodiment, a relatively low-noise two-way valve connection between three channels can be obtained. A combination of this low-noise valve with a low-noise centrifugal fan is very advantageous when used in a ventilation system for a vehicle.

Fig. 9 shows this combination, where a centrifugal fan 16 is connected to a valve according to the exemplary embodiment shown in Figs. 1-4 in the place of the third channel 6 shown in those Figures. The fan can pump air from the first channel 1 and the second channel 2, respectively, to an outlet channel 17, depending on the position of the valve body 4 of the valve. The valve body 4 in each case forms a substantially gradual connection between the wall of a channel 1,2 and the wall 19 of an inlet 18 of the fan 16, so that

the valve produces relatively little noise during use of the combination shown.

It will be clear that the invention is not limited to the exemplary embodiments described. Various modifications are possible within the scope of the invention as set forth in the following claims, which variants will be clear to those skilled in the art.

Thus, the first, second and third channel, at least adjacent the two- way valve, may extend substantially in the same plane or in two or three different planes. The channels may be provided with a circular, angular or differently shaped cross-section. The cross-sections of the first, second and third channels may be equal to each other or may be different from each other.

Further, the valve body may be provided with different means for bringing the body into the first or second valve shape. Thus, the valve body may be provided with memory metal, the valve body assuming the first and the second valve shape in a respective first and second memory condition of the memory metal.

Furthermore, for instance, a number of the two-way valves according to the invention may be placed in cascade with or without intermediate connecting channels, so that more than three channels can be connected to each other, in a substantially low-noise manner.

The valve body 4, besides being bendable, may also be, for instance, bistable. The body may then be brought into a stable valve shape through cooperation with a wall of a channel during operation, or in a different manner.

Furthermore, the valve may be provided with a valve housing, which surrounds the valve body partly or completely. The valve housing may, for instance, comprise a part of each of the channels 1,2, 6. Such a valve housing may further be, for instance, detachably coupled to channel walls of remaining parts of the channels 1,2, 6, so that the valve can be relatively

easily removed from between the channels, for instance for repair or replacement. Furthermore, each channel 1,2, 6 may comprise, for instance, a number of channel parts that extend each other, which channel parts are fixedly or detachably joined together.