FIELD OF THE INVENTION

The present invention relates to a device for switching between air passages, particularly a device for switching between a plurality of air passages in an air ventilation unit.

BACKGROUND OF THE INVENTION

Proper interior ventilation is vital to maintain comfort, health and indoor air quality in an indoor environment. In order to achieve and maintain good indoor air quality and thermal comfort, a ventilation system works to freshen up air inside an indoor area by circulating the air in and out so to allow a constant inflow of outdoor air. However, there are certain circumstances where the outdoor air becomes more polluted than the indoor air. For instance, during periods of haze, the outdoor air may not be suitable to be drawn into the indoor area to dilute indoor airborne pollutants. Under such circumstance, some of the ventilation systems have been recently provided with an in-built air purifier that introduces an air purification mode which is found to be effective in eliminating haze particles or even smaller particles from indoor air. The aim of integrating the air purification mode into the ventilation system is to purify the indoor air via the in-built air purifier when the outdoor air quality is poor. Apart from the existing air flow paths provided for ventilation operation, a different air flow path is required for the indoor air purifying operation in order to direct the air flow to return to the indoor area after being drawn into the ventilation system.

For the ventilation system to alternately switch between the ventilation mode and the air purification mode, the ventilation system requires a device for switching between multiple air flow paths whereby each air flow path interconnecting an inlet to an outlet for each operation mode. One of the commonly used devices for switching between the air flow paths in the ventilation system is the damper serving as an air flow control device installed at an air passage connected to an air flow path, in which the damper can either fully close or open the air passage for allowing air to flow into the air flow path. The damper acts like a switching door which is movable between a closed position for blocking an air flow and an open position for allowing air to pass through the air passage.

Patent document W02019107162A1 discloses a ventilation system incorporated with an air purification function. The ventilation system comprises a plurality of dampers for blocking and regulating air flow when the ventilation system performs one of the operation modes. Each of the dampers is installed at one air passage for each air flow path and is controlled to move between an open position for enabling airflow to pass through the air passage and a closed position for blocking the air flow. Nevertheless, such configuration may contribute to a higher energy consumption as multiple dampers are installed in the system and hence multiple driving motors are required to control the dampers between the open and the closed position. Also, as there are multiple dampers required to be installed in the ventilation system for switching between the air passages for different air flow paths, this may require more space and components. The interior configuration of the ventilation system may become complicated as well. Thus, the cost of production could be higher.

Another device as disclosed in US10184684B2 for switching an air passage for an air flow path in a ventilation system comprises two blades pivotally mounted in a cylindrical housing wall. There are two devices installed in the ventilation system. The prior art still requires more than one device for the operation of the ventilation system as the two devices are required to work in connection with each other for switching between the air passages for multiple operation modes. It seems not possible that such individual device could integrate all the three air passages which are made to be switchable among each other to achieve a more efficient air flow control.

Accordingly, it can be seen in the prior art documents that there exists a need to have a device capable of switching between a plurality of air passages for performing multiple operation modes which overcomes the aforesaid problems and shortcomings.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a device for switching between a plurality of air passages that works effectively with multiple operation modes in a ventilation system.

It is an objective of the present invention to provide a device for switching between a plurality of air passages that operates in an energy efficient manner, thereby reducing energy consumption as well as the cost.

Another objective of the present invention is to provide a device for switching between a plurality of air passages that requires fewer components and less space as compared to the conventional device, thereby saving cost of production.

It is a further objective of the present invention to simplify the configuration of a ventilation system capable of performing multiple operation modes.

Accordingly, these objectives are achievable by following the teachings of the present invention. The present invention relates to a device for switching between a plurality of air passages. The device comprises at least a closure member that slides along a predetermined path to a predetermined position to close the plurality of the air passages while leaving at least one of the plurality of the air passages in an open position, a guiding member that comprises an elongated body pivotally connected to a connecting means with at least one end of the guiding member in contact with at least one end of the closure member, and a driving member for driving the guiding member to rotate around the connecting means so as to direct the closure member to slide to the predetermined position so that the selected air passage is opened for allowing air flowing therethrough.

It is preferred that the closure member is provided with a magnetic element. The guiding member is also provided with a magnetic element having an opposite polarity that generates an attractive force towards the magnetic element on the closure member. More preferably, the magnetic elements are provided on one end of the closure member and one end of the guiding member that will be in contact with the closure member respectively.

Further, the magnetic elements on the closure member and the guiding member attract and hold each other in place when the closure member is directed by the guiding member to slide along the predetermined path to a position.

It is preferred that each end of the predetermined path is provided with a stopper to stop the sliding movement of the closure member. Preferably, the predetermined path is a guide rail and more preferably a semi-circular guide rail.

Preferably, the driving member is a stepping motor that drives the guiding member to rotate.

In another preferred embodiment of the present invention, the device comprises two closure members for closing at least two air passages while leaving at least one passage in an open position.

According to another aspect of the present invention, an air ventilation unit for performing a plurality of operation modes is provided. The air ventilation unit comprises a body, a heat exchanger disposed in the body for exchanging heat between an exhaust air flow from an indoor area to an outdoor area and a supply air flow from an outdoor area to an indoor area, a plurality of air flow paths provided in the body for allowing air flow to pass through during each operation mode and a device as described above for switching between a plurality of air passages that provide access to the plurality of air flow paths.

The body of the air ventilation unit comprises an outdoor air suction port, an indoor air exhaust port, an indoor air suction port and an air supply port.

Preferably, the device for switching between the plurality of air passages comprises at least two closure members slidable along a predetermined path to a predetermined position to close the plurality of the air passages while leaving at least one of the plurality of the air passages in an open position, a guiding member having an elongated body pivotally connected to a connecting means with at least one end of the guiding member in contact with at least one of the closure members, and a driving member for driving the guiding member to rotate around the connecting means so as to direct the two closure members to slide to the predetermined position so that the selected air passage is opened for allowing air to pass therethrough and to flow into the selected air flow path.

Preferably, the plurality of the operation modes comprise at least a heat recovery ventilation mode, a normal ventilation mode and an air purification mode.

Further, the air ventilation unit comprises a first blower for drawing air from the indoor air suction port and blowing the air towards the indoor air exhaust port, and a second blower for drawing air from the indoor air suction port or from the outdoor air suction port and blowing the air towards the air supply port.

When the air ventilation unit is configured to perform the heat recovery ventilation mode, the driving member of the device drives the guiding member to direct the two closure members to a predetermined position so as to keep at least a first air passage of the device in an open position while closing at least a second air passage and a third air passage of the device, enabling indoor air to be drawn from the indoor air suction port, passing through the heat exchanger and exiting through the indoor air exhaust port to the outdoor area as the exhaust air flow. The air ventilation unit further allows drawing of outdoor air to be from the outdoor air suction port, passing through the heat exchanger and exiting through the air supply port to the indoor area as the supply air flow.

Preferably, the air ventilation unit comprises a purification unit for purifying air when performing the air purification mode.

When the air ventilation unit is configured to perform the air purification mode, the driving member of the device drives the guiding member to direct the two closure members to close at least a first air passage and a third air passage of the device, leaving at least a second air passage of the device in an open position where indoor air is drawn from the indoor air suction port to pass through the purification unit and the purified air is circulated back to the air supply port.

Preferably, the air ventilation unit comprises a bypass flow path for allowing discharge of indoor air to the outdoor area without passing through the heat exchanger when performing the normal ventilation mode.

When the air ventilation unit is configured to perform the normal ventilation mode, the driving member of the device drives the guiding member to direct the two closure members to close at least a first air passage and a second air passage of the device, leaving at least a third air passage of the device in an open position where indoor air is drawn from the indoor air suction port into the bypass flow path and is then discharged through the indoor air exhaust port to the outdoor area as the exhaust air flow. The air ventilation unit further allows drawing of outdoor air from the outdoor air suction port and exiting through the air supply port to the indoor area as the supply air flow.

It is further preferred that the air ventilation unit comprises a control system for automatically switching between the plurality of the operation modes based on at least one ambient parameter for instance indoor and outdoor temperatures, carbon dioxide concentration, volatile organic compounds concentration, air borne particulates concentration or other relevant ambient parameters.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The features of the invention will be more readily understood and appreciated from the following detailed description when read in conjunction with the accompanying drawings of the preferred embodiments of the present invention, in which:

Figure 1 illustrates a front perspective view of a device for switching between a plurality of air passages according to the present invention.

Figures 2a to 2c illustrate top views of a device for switching between a plurality of air passages according to the present invention.

Figure 3a illustrates a plan view of an air ventilation unit provided with a device for switching between a plurality of air passages for multiple air flow paths according to a preferred embodiment of the present invention.

Figure 3b illustrates a front perspective view of the device for switching between the plurality of air passages of Fig. 3a.

Figure 4a illustrates a plan view of an air ventilation unit provided with a device for switching between a plurality of air passages for multiple air flow paths according to a preferred embodiment of the present invention.

Figure 4b illustrates a front perspective view of the device for switching between the plurality of air passages of Fig. 4a. Figure 5a illustrates a plan view of an air ventilation unit provided with a device for switching between a plurality of air passages for multiple air flow paths according to a preferred embodiment of the present invention.

Figure 5b illustrates a front perspective view of the device for switching between the plurality of air passages of Fig. 5a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described, and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim. As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one” and the word “plurality” means “more than one” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other components, integers or steps. Any discussion of documents, materials, devices, and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention.

The present invention is described hereinafter by various embodiments with reference to the accompanying drawings, wherein reference numerals used in the accompanying drawings correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. The present invention will now be described with reference to Figs. 1-5.

The present invention relates to a device (100) for switching between a plurality of air passages. The device (100) is suitable for use in any fluid flow regulating system. Preferably, the fluid flow regulating system is an air treating system comprising a ventilation system and an air purification system. More preferably, the device (100) is suitable for use in an air ventilation unit (200) that provides multiple operation modes comprising at least a heat recovery ventilation mode, a normal ventilation mode and an air purification mode. The air ventilation unit (200) may work in connection with a heating system, a cooling system, an air conditioning system or other systems for heating or/and cooling purposes. The air ventilation unit (200) may also work individually and independently of other systems.

In a preferred embodiment of the present invention, the device (100) comprises at least a closure member (101) that is slidable along a predetermined path to a predetermined position for closing the plurality of air passages while leaving at least one of the plurality of the air passages in an open position, a guiding member (102) that is rotatable for directing the closure member (101) to slide, and a driving member (103) for driving the guiding member (102) to rotate. The guiding member (102) comprises an elongated body that is pivotally connected to a connecting means and at least one of its ends is in contact with at least one end of the closure member (101). The driving member (103) is configured to drive the guiding member (102) to rotate around the connecting means so that the closure member (101) is directed to slide to the predetermined position where the at least one of the plurality of the air passages is opened for allowing air to flow therethrough.

In a preferred embodiment of the present invention, each closure member (101) is provided with at least one magnetic element (104a) and the guiding member (102) is also provided with at least one magnetic element (104b) that has an opposite polarity to generate an attractive force towards the magnetic element (104a) on the closure member (101). More preferably, the magnetic elements (104a, 104b) are respectively provided on one end of the closure member (101) and one end of the guiding member (102) that will be in contact with the closure member (101). Further, the magnetic elements (104a, 104b) on the closure member (101) and the guiding member (102) will attract and hold each other in place when the closure member (101) is directed by the guiding member (102) to slide along the predetermined path to the predetermined position.

In a preferred embodiment of the present invention, each end of the predetermined path is provided with at least a stopper (105) for stopping the sliding movement of the closure member (101). The stopper (105) may not be necessarily disposed at the end of the predetermined path but at a position where the closure member (101) terminates its sliding movement. Further, the predetermined path is preferably, but not limited to, a guide rail (107) and more preferably a semi-circular guide rail (107). The guide rail (107) is preferably shaped to conform to the shape of the closure member (101) so as to allow the closure member (101) sliding back and forth along the guide rail (107) in a smooth manner.

In a preferred embodiment of the present invention, the driving member (103) is a stepping motor that drives the guiding member (102) to rotate. The guiding member (102) is driven by the driving member (103) to rotate around the connecting means either in a clockwise or anti-clockwise direction for directing the closure member (101) to slide to the predetermined position for closing the plurality of air passages, allowing at least one air passage in an open position for air flow. The guiding member (102) will return to its original position when the driving member (103) is not driving the guiding member (102) to rotate in any direction.

Fig. 1 illustrates another preferred embodiment of the device (100). The device (100) comprises two closure members (101) for switching between at least three air passages. The two closure members (101) are slidable along a predetermined path to a predetermined position for closing two air passages while leaving at least one air passage in an open position. The two closure members (101) are preferably formed as outwardly curved-shaped structures that are slidable along the predetermined path, preferably a semi-circular guide rail (107) with at least two stoppers (105) disposed at each end. Further, the guiding member (102) is preferably formed as a bar-like or rod-like structure that has an elongated body with at least one end in contact with one end of each closure member (101). The guiding member (102) are provided with magnetic elements (104b) on both of its ends, while the two closure members

(101) are respectively provided with a magnetic element (104a) on one end which will be in contact with the guiding member (102). Both magnetic elements (104a, 104b) on the closure member (101) and the guiding member (102) are oriented facing towards each other.

The guiding member (102) is driven by a driving member (103) to rotate around a connecting means in order to direct the two closure members (101) sliding back and forth along the predetermined path. When the guiding member

(102) is driven to approach one of the closure members (101), the magnetic element (104a) on the closure member (101) and the corresponding magnetic element (104b) on one end of the guiding member (102) will attract and engage with each other due to attractive force. The engaged closure member (101) is then directed by the guiding member (102) to slide along the predetermined path until the closure member (101) hits the stoppers (105) at the end of the predetermined path and is stopped from sliding further. The guiding member (102) is driven to continue moving past the stopper (105) and forcing the mutually attracting magnetic elements (104a, 104b) to disengage from each other. At the same time, the other end of the guiding member (102) is moving towards another closure member (101) and their magnetic elements (104a, 104b) engage with each other. The guiding member (102) that is engaged with the closure member (101) then pushes the engaged closure member (101) towards the closure member (101) that has been stopped by the stoppers (105).

Referring to Figs. 2a to 2c, the two closure members (101) of the device (100) are configured to switch between three air passages by closing two of the air passages, leaving only one air passage in an open position. When the device (100) is configured to open a first air passage at the middle as shown in Fig. 2a, the driving member (103) will not drive the guiding member (102) to rotate and the guiding member (102) will remain in its original position where the magnetic element (104b) on each end of the guiding member (102) engages with the magnetic element (104a) on each closure member (101) respectively. The two closure members (101) are arranged in a way that the first closure member (101) closing a second air passage at one side and the second closure member (101) closing a third air passage at another side. The magnetic elements (104a) on the two closure members (101) and the magnetic elements (104b) on the guiding member (102) will keep engaging with each other to maintain the position of the two closure members (101) so that the first air passage is kept in an open position.

When the device (100) is configured to switch open the second air passage, as illustrated in Fig. 2b, from the first air passage, the guiding member (102) is forced to disengage from the second closure member (101) and the rotating guiding member (102) continues engaging with the first closure member (101) and pushing it towards the second closure member (101) until they stay adjacent to each other. The magnetic elements (104a, 104b) on the guiding member (102) and the first closure member (101) keep holding each other so as to fixedly secure the two closure members (101) in their predetermined position on the predetermined path, leaving the second air passage in an open position.

When the device (100) is configured to switch open the third air passage, as illustrated in Fig. 2c, from the second air passage, the two closure members (101) are directed to slide towards another end of the predetermined path to close the first air passage and the second air passage. When the driving member (103) drives the guiding member (102) to rotate in an anti-clockwise direction, the guiding member (102) directs the first closure member (101) to slide to close the second air passage. The sliding of the first closure member (101) is then stopped by the stopper (105) and the guiding member (102) is forced to disengage from the first closure member (101). At the same time, the other end of the guiding member (102) is driven to engage with the second closure member (101) and continue pushing it towards the first closure member (101) until they stay beside each other, closing the first and the second air passages of the device (100).

In a preferred embodiment of the present invention, the device (100) may further comprise a generally semi-cylindrical housing wall (106) on which the two closure members (101) abut and slide over when being directed by the guiding member (102) as illustrated in Figs 3b, 4b and 5b. The semi-circular guide rail (107) is preferably disposed on the top of the two closure members (101) at the upper part of the semi-cylindrical housing wall (106). Further, the semi-cylindrical housing wall (106) preferably comprises an opening to be closed partially by the two closure members (101) so that a portion of the opening is selectively left open to enable access to one of the plurality of the air passages. In another embodiment, the semi cylindrical housing wall (106) may comprise at least three openings formed at positions corresponding to each air passage. The openings would be closed by the two closure members (101), leaving at least one opening in an open position for allowing air to flow therethrough. With reference to Figs. 3a, 4a and 5a, the device (100) is installed in an air ventilation unit (200) comprising a plurality of air flow paths and the device (100) is used for switching between a plurality of air passages providing access to the plurality of air flow paths for performing multiple operation modes. Preferably, the multiple operation modes comprise at least a heat recovery ventilation mode, a normal ventilation mode and an air purification mode.

The air ventilation unit (200) comprises a body (210) and a heat exchanger (220) disposed in the body (210) for exchanging heat between an exhaust air flow and a supply air flow. The exhaust air flow is a flow of air from indoor to outdoor, while the supply air flow is a flow of air from the outdoor to the indoor.

The body (210) comprises a plurality of air inlets and outlets that are interconnected by the plurality of air flow paths in the body (210). In particular, the plurality of air inlets and outlets comprise an outdoor air suction port (211) for suctioning outdoor air, an indoor air exhaust port (212) for discharging indoor air to an outdoor area, an indoor suction port (213) for suctioning indoor air, and an air supply port (214) for supplying air to an indoor area. The outdoor air suction port (211) and the indoor air exhaust port (212) are provided on the outdoor side surface of the body (210), while the indoor air suction port (213) and the air supply port (214) are provided on the indoor side surface of the body (210).

Preferably, there are at least four air flow paths in the body (210) to enable the air inlets and outlets to communicate with each other. A first air flow path is preferably an exhaust air flow path (as indicated as dashed line in Fig. 3a) through which indoor air drawn from the indoor air suction port (213) and discharged to the outdoor area through the indoor air exhaust port (212) as the exhaust air flow. A second air flow path is preferably an air circulation path (as indicated as bold solid line in Fig. 4a) through which indoor air drawn from the indoor air suction port (213), purified by a purification unit and circulated back to the indoor area via the air supply port (214). The purification unit is provided in the air ventilation unit (200) for eliminating contaminants, microorganisms or dust particles from the circulating airflow. A third air flow path is in parallel with the first air flow path and it is preferably a bypass flow path (as indicated as dashed line in Fig. 5a) through which indoor air drawn from the indoor air suction port (213), bypassing the heat exchanger (220) and eventually being discharged to the outdoor area through the indoor air exhaust port (212) as the exhaust air flow. The indoor air is directly discharged to the outdoor area without passing through the heat exchanger (220) in the bypass flow path. A fourth air flow path is preferably an air supply flow path (as indicated as bold solid line in Figs. 3a and 5a) through which outdoor air drawn from the outdoor air suction port (211 ) and supplied to the indoor area through the air supply port (214) as the supply airflow.

When the air ventilation unit (200) is configured to switch from one operation mode to another operation mode, the first airflow path, the second air flow path and the third air flow path are switchable from one to another via the device (100) that switches between the corresponding air passages; while the fourth air flow path is activated whenever there is a supply air flow.

Further, the air ventilation unit (200) is preferably provided with a first blower (230) adjacent to the indoor air exhaust port (212) and a second blower (240) adjacent to the air supply port (214). The first blower (230) operates to generate an exhaust air flow along the first air flow path, whereby air is drawn from the indoor air suction port (213) and is discharged to the outdoor area via the indoor air exhaust port (212). The second blower (240) operates to generate a supply air flow along the fourth air flow path, whereby air is drawn either from the indoor air suction port (213) or the outdoor air suction port (211) and is discharged to the indoor area via the air supply port (214). Furthermore, each blower comprises a motor that drives its operation.

With reference to Fig. 3a, when the air ventilation unit (200) is configured to perform the heat recovery ventilation mode, the air in the indoor area is drawn by the first blower (230) through the indoor air suction port (213) into the first air flow path where the air passes through the heat exchanger (220) and is then discharged to the outdoor area through the indoor air exhaust port (212) as the exhaust air flow. At the same time, the air ventilation unit (200) allows drawing of the outdoor air by the second blower (240) through the outdoor air suction port (211) into the fourth air flow path where the air passes through the heat exchanger (220) and is then discharged to the indoor area through the air supply port (214) as the supply air flow. The exhaust air flow and the supply air flow are simultaneously directed to pass through the heat exchanger (220) for exchanging heat with each other before being discharged from the air ventilation unit (200). As illustrated in Figs. 3a and 3b, the device (100) allows the exhaust air flow to be channeled into the first air flow path by adjusting the position of its closure members (101) so to close its air passages except for the first air passage. The guiding member (102) is driven by the driving member (103) to direct the two closure members (101) to their respective position at which the second air passage and the third air passage of the device (100) are closed while leaving the first air passage at the middle in an open position.

With reference to Fig. 4a, when the air ventilation unit (200) is configured to perform the air purification mode, the air in the indoor area is drawn from the indoor air suction port (213) by the first blower (230) into the second air flow path. Along the second air flow path, the air will pass through the purification unit and the purified air is then circulated back to the indoor area via the air supply port (214). The purification unit can be arranged at any position along the second air flow path in order to purify the air circulating around the indoor area by eliminating airborne particles and contaminants which may lead to health issues and illnesses. The purification unit is preferably a mechanical air filter, a photo catalyzer or a combination of both. Other devices including an ionizer, such as plasma ionizer and plasma discharge device, or an electrostatic precipitator are also applicable as the purification unit. As shown in Figs. 4a and 4b, the device (100) channeling the air flow into the second air flow path when the second air passage of the device (100) is opened. The guiding member (102) of the device (100) is driven by the driving member (103) to direct the two closure members (101) sliding towards one side so that the first air passage and the third air passage of the device (100) are closed while the second air passage of the device (100) is kept in an open position for allowing the air flow to pass therethrough.

With reference to Fig. 5a, when the air ventilation unit (200) is configured to switch its operation mode to the normal ventilation mode, the air in the indoor area is drawn by the first blower (230) through the indoor air suction port (213) into the third air flow path in which the air is directed into the bypass flow path bypassing the heat exchanger (220). The air is eventually discharged from the indoor air exhaust port (212) to the outdoor area. At the same time, the air ventilation unit (200) allows drawing of the outdoor air by the second blower (240) through the outdoor air suction port (211 ) into the fourth air flow path and is then discharged from the air supply port (214) to the indoor area as the supply air flow. The third air flow path provides another route extending across the heat exchanger (220) in which the exhaust air flow could be discharged directly without exchanging heat with the supply air flow. As shown in Figs. 5a and 5b, the device (100) allows the exhaust air flow going through the third air flow path when the third air passage of the device (100) is opened. The guiding member (102) is driven by the driving member (103) to direct the two closure members (101) to slide towards another side so as to close the first air passage and the second air passage of the device (100), leaving the third air passage in an open position.

Further, the air ventilation unit (200) preferably comprises a control system for automatically switching between the plurality of the operation modes based on at least one ambient parameter for instance indoor and outdoor temperatures, carbon dioxide concentration, volatile organic compounds concentration, air borne particulates concentration or any other relevant ambient parameters. The control system may comprise an information acquisition unit for acquiring information of the ambient parameters. The information acquired is used by the control system to control the operation of the device (100) for switching between the plurality of air passages and also to control the operation of each blower for adjusting the speed of the blowers during each operation mode to provide an optimum condition. The control system can be connected to the device (100) in the air ventilation unit (200) to automate the switching mechanism of the device (100) according to each operation mode.

The control system is preferably configured to automatically switch between at least the heat recovery ventilation mode, the normal ventilation mode and the air purification mode in the air ventilation unit (200) based on at least one of the ambient parameters, including, but not limited to, concentration of air borne particulates in outdoor area, indoor temperature, outdoor temperature or a combination thereof. For example, the control system may acquire information regarding the concentration of the air borne particulates in the outdoor area from the information acquisition unit and check if the concentration exceeds a predetermined level. If the concentration of air borne particulates as detected is more than the predetermined level, the air purification mode will be activated to avoid bringing highly polluted air into an indoor area. If the concentration of air borne particulates as detected is less than the predetermined level, the air ventilation unit (200) may select to perform either the heat recovery ventilation mode or the normal ventilation mode to bring outdoor fresh air into the indoor area so as to replace air being exhausted from the indoor area. To determine which ventilation mode to be performed by the air ventilation unit (200), the control system will receive a request signal for cooling or heating the indoor area from a user. Then, the control system will retrieve the measured indoor temperature and the measured outdoor temperature from the information acquisition unit and check which of the temperatures is higher. If the request signal is for cooling the indoor area and the outdoor temperature is higher than the indoor temperature, the heat recovery ventilation mode would be selected to allow the outdoor warm air to be cooled by the indoor cold air when passing across the heat exchanger (220) in the air ventilation unit (200) before the outdoor air being supplied to the indoor area. Also, the same operation mode would be applied if the request signal is for heating the indoor area and the indoor temperature is higher than the outdoor temperature, so that the indoor exhaust hot air could warm up the outdoor cold air in the heat exchanger (220) before the outdoor air being introduced to the indoor area. On the other hand, if the request signal is for cooling the indoor area and the indoor temperature is higher than the outdoor temperature, the normal ventilation mode would be selected to bring the outdoor cold air directly to the indoor area without the need of exchanging heat with the indoor exhaust air. The same mode would be applied if the request signal is for heating the indoor area and the outdoor temperature is higher than the indoor temperature, so that the outdoor warm air is directly brought into the indoor area without involving heat exchanging process. The outdoor air supplied from the air ventilation unit (200) may be further conditioned by any heating, ventilation or air conditioning system before entering the indoor area.

The speed of the first blower (230) and the second blower (240) during each operation mode could be also automatically adjusted by the control system based on at least one of the ambient parameters, for example, carbon dioxide concentration, volatile organic compounds concentration and air borne particulates concentration measured in indoor area. As an example, during the heat recovery ventilation mode or the normal ventilation mode, the speed of the blowers could be automatically adjusted by the control system based on the carbon dioxide concentration, the volatile organic compounds concentration and the air borne particulates concentration in the indoor area; while for the air purification mode, the speed of the blowers could be automatically adjusted based on the volatile organic compounds concentration and the air borne particulates concentration in the indoor area. The indoor concentration of the mentioned pollutants is necessary to be maintained within an acceptable range which is safe for human health. The range could be further defined by a first predetermined level and a second predetermined level in which the first predetermined level is higher than the second predetermined level. If one of these concentrations is found to be higher than the first predetermined level in the indoor area, the control system will adjust the blowers to be operated at a high speed so as to reduce indoor air pollutants’ level and to maintain indoor air quality. If all the concentrations are lower than the first predetermined level but at least one of them is found to be higher than the second predetermined level in the indoor area, the control system will adjust the blowers to be operated at a medium speed. However, if none of the concentrations are found to be higher than the second predetermined level in the indoor area, the control system will adjust the blowers to be operated at a low speed so as to reduce unnecessary energy usage.

It can be seen from the description above that the device (100) of the present invention provides a number of advantages over the existing devices. One of the advantages is that the device (100) contributes to a compact and simplified configuration of an air ventilation unit (200). Fewer components and lesser space are required for incorporating the device (100) into the air ventilation unit (200). Further, the working mechanism of the device (100) to switch between the plurality of the air passages is simple and efficient, thereby increasing efficiency of the air ventilation unit (200). In addition, the device (100) could help in saving energy and the cost thereof as the device (100) only require a driving motor to switch between at least three air passages in the air ventilation unit (200). Furthermore, the device (100) can be connected to a control system to automate its switching mechanism in the air ventilation unit (200) so that the operation modes of the air ventilation unit (200) can be automatically adjusted based on the aforementioned parameters.

The exemplary implementation described above is illustrated with specific shapes, dimensions, and other characteristics, but the scope of the invention also includes various other shapes, dimensions, and characteristics. For example, the number and the geometric configuration of the closure members (101) could be modified to adapt to any appropriate particular combination of various parts of the device (100).

Various modifications to these embodiments are apparent to those skilled in the art from the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the embodiments shown along with the accompanying drawings but is to be providing broadest scope of consistent with the principles and the novel features disclosed or suggested herein. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present invention and appended claims.