FIELD

The invention relates to an extractor assembly for extracting fluid from above a domestic cooker, as well as to a cooker arrangement comprising such an extractor assembly, and to a method for adjusting a discharge volume flow rate ratio.

BACKGROUND

Extractor assemblies for extracting fluid from above a domestic cooker are known in various forms. Thus, on the one hand, ventilation-type assemblies are known which discharge extracted fluid to an open-air environment. On the other hand, recirculation-type assemblies are known which lead extracted fluid via a filter back to an inside environment in which the cooker is placed. An advantage of the recirculation type is that heat loss from the inside environment can be limited. An advantage of the ventilation type is that the air quality in the inside environment can be better maintained at a proper level, for instance regarding CO2, water vapour, fine particles and odours.

From EP2151632B1 an extractor assembly is known in which the ventilation type and the recirculation type are combined, with valves that, depending on outside and inside temperature sensor values, are controlled to discharge extracted fluid selectively to the open-air environment, to the inside environment, or at the same time partly to one and partly to the other environment, with the discharge to the open-air environment, in case of a low outside temperature, being switched on only when the total discharge flow rate is greater than a threshold value.

There is an ongoing need for further improvements in the area of extraction for domestic cookers. SUMMARY

An object of the invention is to improve extraction for domestic cookers, whereby one or more disadvantages of known extraction assemblies are at least partly removed while corresponding advantages are retained. An object is to optimize inside air quality during the use of domestic cookers and at the same time limit heat loss as far as possible without deterioration of the air quality. An object is to provide a relatively robust extractor assembly that is relatively low-maintenance. An object is to provide at least an alternative extractor assembly.

To this end, according to an aspect of the invention, an extractor assembly according to claim 1 is provided for extracting fluid from above a domestic cooker. The extractor assembly comprises a fan housing having therein a motorized fan, wherein the fan housing is provided with a fan housing outlet and at least one fan housing inlet which during operation can let in fluid from above the domestic cooker. The extractor assembly further comprises a discharge assembly provided with a discharge assembly inlet which is connected with the fan housing outlet and further provided with a ventilation outlet which during operation is in communication with an open-air environment and at least one recirculation outlet which during operation communicates with an inside environment where the domestic cooker is placed and which is provided with a respective recirculation filter.

The extractor assembly is configured, at least in a combination work position, to discharge fluid which has been extracted by the motorized fan, partly via the ventilation outlet and at the same time partly via the at least one recirculation outlet. In this regard, a corresponding discharge volume flow rate via the ventilation outlet is defined as ventilation volume flow rate V, while a corresponding discharge volume flow rate via the at least one recirculation outlet is defined as recirculation volume flow rate R. A sum of the ventilation volume flow rate V and the recirculation volume flow rate R is defined as total discharge volume flow rate V+R, and a ratio of the ventilation volume flow rate with respect to the recirculation volume flow rate is defined as discharge volume flow rate ratio V/R.

The total discharge volume flow rate V+R, during operation in the combination work position, is adjustable by adjustment of a motor power of the motorized fan. The discharge assembly is configured to have the discharge volume flow rate ratio V/R in the combination work position automatically vary along with the total discharge volume flow rate V+R, such that the discharge volume flow rate ratio V/R automatically increases when the total discharge volume flow rate V+R increases, and automatically decreases when the total discharge volume flow rate V+R decreases.

By thus having the discharge volume flow rate ratio V/R automatically vary along with the total discharge volume flow rate V+R, it is achieved that recirculation via the recirculation filter can be utilized as far as possible without deterioration of the inside air quality, so that heat loss can be limited while yet a good inside air quality can be constantly maintained. Because the automatic varying along can take place within the combination work position, a relatively precise regulation of the discharge volume flow rate ratio for different total discharge volume flow rates is enabled. As is indicated elsewhere in this description, having the discharge volume flow rate ratio automatically vary along can advantageously be realized without use of control engineering, in particular without use of any sensor. Thus, it will be clear that the above-mentioned relatively precise regulation of the discharge volume flow rate ratio, as well as the use of the term ‘automatically’ in this disclosure, must not be construed as if this would necessarily require any control loop such as that of a traditional sensor-based control system.

For that matter, it is not excluded that the discharge volume flow rate ratio V/R is additionally adjustable in one or more ways other than by the above-mentioned varying along. For instance, the discharge assembly may be adjustable between the combination work position and a full-recirculation work position, i.e., a work position in which the discharge volume flow rate ratio V/R is 0/100. A further possibility is that the discharge assembly is settable for supplementary influencing of the discharge volume flow rate ratio V/R. The additional possibilities mentioned are further explained elsewhere in this description.

A further aspect provides a cooker arrangement comprising a cooker and an extractor assembly according to the invention placed above the cooker for extracting fluid from above the cooker.

With such a cooker arrangement the above-mentioned advantages can be achieved.

A further aspect provides a method for adjusting a ventilation/recirculation discharge volume flow rate ratio in an extractor assembly for extracting fluid from above a domestic cooker.

The method comprises providing an extractor assembly as herein described, wherein the discharge assembly comprises a separation assembly disposed directly downstream of the motorized fan, having at least one separating element which separates a fluid stream coming from the fan into at least two streams including a stream through the ventilation outlet and at least one stream through the at least one recirculation outlet, wherein a work position of a fan-facing end of the at least one separating element with respect to the fan housing outlet is settable, at least when the extractor assembly is not in operation, for settable influencing of the discharge volume flow rate ratio V/R supplementary to having the discharge volume flow rate ratio V/R automatically vary along with the total discharge volume flow rate V+R.

The method further comprises changing the setting of the work position of the fan-facing end of the at least one separating element with respect to the fan housing outlet, for adjustment of the discharge volume flow rate ratio V/R supplementary to having the discharge volume flow rate ratio V/R automatically vary along with the total discharge volume flow rate V+R.

Such a method makes it possible to set the extractor assembly as desired to generally increase or decrease the discharge volume flow rate ratio V/R, that is, as a general supplementation to the varying along with the total discharge volume flow rate V+R, always present in the combination position. Thus, the actual discharge volume flow rate ratio V/R during operation can be determined partly by the setting mentioned and partly by the varying along mentioned, yielding further increased possibilities to limit heat loss while the inside air quality is optimized. In particular, the extractor assembly can thus be adjusted to specific use conditions.

Advantageous further elaborations of the invention are provided by the features of the dependent claims, as further explained in the following detailed description.

DETAILED DESCRIPTION

In the following, the invention will be further explained on the basis of examples of embodiments and drawings. The drawings are schematic and merely show examples. In the drawings, corresponding elements are designated with corresponding reference signs. In the drawings:

Fig. 1 shows a perspective view of a cooker arrangement with an extractor assembly;

Fig. 2 shows a side view of a cooker arrangement with an extractor assembly;

Fig. 3 shows a partly cutaway perspective view of an extractor assembly;

Fig. 4 shows a further cutaway, further perspective view of the extractor assembly of Fig. 3; Fig. 5 shows a visualization in perspective of fluid streams through a separation assembly;

Fig. 6A and Fig. 6B each show a front view in cross section of the extractor assembly of Fig. 4, wherein the extractor assembly in Fig. 6 A is in a combination position and in Fig. 6B is in a full-recirculation position; and Fig. 7 A and Fig. 7B each show a bar chart with an example of different discharge volume flow rate ratios at different motor power levels.

Figs. 1-4 and Figs. 6A-B show examples of an extractor assembly 1 for extracting fluid from above a domestic cooker 2. Figs. 1 and 2 show examples of a cooker arrangement 19 comprising a cooker 2 and an extractor assembly 1 placed above the cooker 2.

The extractor assembly 1 comprises a fan housing 3 having therein a motorized fan 4, the fan housing 3 being provided with a fan housing outlet 5 and at least one fan housing inlet 6 which during operation can let in fluid from above the domestic cooker 2.

In embodiments, the extractor assembly 1 further comprises a hood 16 which bounds an extraction space 17 with which the at least one fan housing inlet 6 is in communication. With such a hood 16 fluid from above the cooker 2 can be effectively guided to the fan housing inlet 6.

The extractor assembly 1 further comprises a discharge assembly 7 provided with a discharge assembly inlet 8 which is connected with the fan housing outlet 5 and further provided with a ventilation outlet 9 which during operation is in communication with an open-air environment OE, and at least one recirculation outlet 10, in the example shown two recirculation outlets 10, which during operation is in communication with an inside environment IE where the domestic cooker 2 is placed and which is provided with a respective recirculation filter 11. The connection with the open-air environment OE runs for instance via a ventilation discharge channel of a building in which the cooker arrangement 19 is placed. In embodiments, the at least one recirculation outlet 10 is provided in a respective at least one sidewall 18 of the hood 16. Thus, air from the recirculation outlet 10 can be distributed relatively evenly, in particular when, as in the example shown, a recirculation outlet 10 is provided in two or more mutually spaced apart sidewalls 18.

In embodiments, the recirculation filter 11 is a plasma filter. Plasma filters are particularly effective as a recirculation filter, one reason being that plasma filters can break down fatty particles in the fluid passing through the filter.

In embodiments, the plasma filter 11 is configured to switch itself on when a volume flow rate through the plasma filter 11 is greater than a predetermined limiting value. This can counteract the plasma filter getting soiled when extracted fluid passes through the filter while it is not switched on. At the same time, in this way, waste of energy due to unnecessary operation of the filter can be counteracted, in particular when the filter is further configured to switch itself off when the volume flow rate is less than a predetermined limiting value. The independent switching on and off may for instance be realized using a flow sensor such as a differential pressure sensor.

In embodiments, the discharge assembly 7 comprises at least one recirculation channel 15 which connects the discharge assembly inlet 8 with the at least one recirculation outlet 10. Thus, a distance between the discharge assembly inlet 8 and the at least one recirculation outlet 10 can be effectively bridged, for instance when the at least one recirculation outlet 10 is provided in a sidewall 18 of the hood 16.

In embodiments, a cross-sectional area of the at least one recirculation channel 15 is small with respect to a passage area of the respective recirculation filter 11. With this feature, it can be achieved that a flow velocity through the at least one recirculation channel 15 is relatively high, in consequence of which the independent switching on of the filter 11 can take place already at a relatively low flow rate, in particular because such a low flow rate, due to the relatively high velocity, can still be properly detectable by a flow sensor such as a differential pressure sensor of the filter 11.

The extractor assembly 1 is configured, at least in a combination work position (shown in Figs. 1, 2, 5 and 6A), to discharge fluid extracted by the motorized fan 4 partly via the ventilation outlet 9 and at the same time partly via the at least one recirculation outlet 10. A corresponding discharge volume flow rate via the ventilation outlet 9 is defined as ventilation volume flow rate V and a corresponding discharge volume flow rate via the at least one recirculation outlet 10 is defined as recirculation volume flow rate R. A sum of the ventilation volume flow rate V and the recirculation volume flow rate R is defined as total discharge volume flow rate V+R, while a ratio of the ventilation volume flow rate with respect to the recirculation volume flow rate is defined as discharge volume flow rate ratio V/R.

The total discharge volume flow rate V+R, during operation in the combination work position, is adjustable by adjustment of a motor power of the motorized fan 4.

The discharge assembly 7 is configured to have the discharge volume flow rate ratio V/R, in the combination work position, automatically vary along with the total discharge volume flow rate V+R, such that the discharge volume flow rate ratio V/R automatically increases when the total discharge volume flow rate V+R increases, and automatically decreases when the total discharge volume flow rate V+R decreases.

The possibilities set out in the current detailed description relate at least to the combination work position mentioned, except where indicated otherwise herein.

In embodiments, the motor power of the motorized fan 4 is adjustable during use between at least two different levels, including a first level wherein the recirculation volume flow rate R is greater than the ventilation volume flow rate V and a higher second level wherein the recirculation volume flow rate R is less than the ventilation volume flow rate V. Thus, for a relatively large range as regards total discharge volume flow rate V+R, an appropriate discharge volume flow rate ratio V/R can be provided.

In embodiments, the discharge volume flow rate ratio V/R at the first level is less than 40/60, preferably less than 30/70, for example circa 20/80. In embodiments, the discharge volume flow rate ratio V/R at the second level is greater than 60/40, preferably greater than 65/35, for example circa 70/30. In this way, the herein described advantages of having automatic varying along are enhanced.

In embodiments, the motor power is further adjustable to at least one, preferably two, more preferably three, intermediate levels between the first level and the second level. Thus, the motor power can be set relatively precisely during use, for instance depending on a quantity and/or quality of the fluid above the cooker.

The motor power level may for instance be chosen by a user via an operating element, not shown, that may for instance be provided on the hood 16, on the cooker 2, and/or on a remote control. Alternatively or additionally, the motor power level may be wholly or partly automatedly adjusted, for instance based on one or more sensor values and/or coupled to one or more settings, such as a heating level, of the cooker 2.

To illustrate the above possibilities concerning the motor power and the discharge volume flow rate ratio, Fig. 7A and Fig. 7B each show an example of a possible relation between, on the one hand, a motor power level and, on the other hand, the ventilation volume flow rate V and the recirculation volume flow rate R as a percentage of the total discharge volume flow rate V+R. The motor power level is here plotted along the horizontal axis and here comprises the above-mentioned first level Ml, the above-mentioned second level M5, and the three intermediate levels M2, M3, and M4, with M2 < M3 < M4. The motor power levels Ml through M5 typically correspond to the total discharge volume flow rate V+R, at least in the sense that a higher motor power level is associated with a higher total discharge volume flow rate V+R.

In Fig. 7 A, for instance, it can be seen that the discharge volume flow rate ratio V/R at the first level Ml is 20/80, at intermediate level M3 45/55, and at the second level M5 70/30. Fig. 7B shows a possible alternative, where the discharge volume flow rate ratio V/R varies from 30/70 at the first level Ml to 80/20 at the second level M5. It will be clear that the invention is not limited to the examples shown here of relations between motor power levels and discharge volume flow rate ratio V/R. Moreover, such a relation can be at least partly settable, as is further explained elsewhere in this description.

In embodiments, the discharge assembly 7 is configured to realize having the discharge volume flow rate ratio V/R automatically vary along, without mechanical variation of the discharge assembly 7, in particular without any valve movement in the discharge assembly 7. As a result, the discharge assembly 7 and the entire extractor assembly 1 can be particularly robust and low-maintenance, in particular in that wear of moving parts can be limited.

In embodiments, the discharge assembly 7 is configured to realize having the discharge volume flow rate ratio V/R automatically vary along, without use of control engineering, in particular without use of any sensor. As a result, the discharge assembly 7 and the entire extractor assembly 1 can be particularly robust and low-maintenance, in particular in that the use of fragile sensors can be limited.

In embodiments, as for instance shown in Fig. 6A, the discharge assembly 7 comprises a separation assembly 12 disposed directly downstream of the motorized fan 4, having at least one separating element 13 which separates a fluid stream coming from the fan 4 into at least two streams including a stream F9 through the ventilation outlet 9 and at least one stream F10 through the at least one recirculation outlet 10. By disposing such a separation assembly 12 directly downstream of the fan 4, the separation of the streams mentioned can take place advantageously at a relatively low static pressure, so that the separation is relatively insensitive to resistance associated with the ventilation outlet 9 and/or the at least one recirculation outlet 10. An additional advantage is that the separation assembly 12 itself in this way causes relatively little resistance, as a result of which the motor power of the fan 4 and an associated noise production can remain relatively low while still a desired discharge volume flow rate can be realized.

In embodiments, the motorized fan 4 is a centrifugal fan which during operation rotates around a fan axis W which extends transversely to an outlet direction of the fan housing outlet 5, wherein the centrifugal fan 4 extends along the fan axis W between two lateral ends which correspond to two lateral sides 14 of the fan housing outlet 5.

Rotor blades of the centrifugal fan 4 are preferably of the so-called forward-curved type, because with this type a noise production of the fan 4 in use can be relatively low.

In particularly advantageous embodiments, the separation assembly 12 is configured such that at the fan housing outlet 5 the stream F9 through the ventilation outlet 9, compared with the at least one stream F10 through the at least one recirculation outlet 10, is positioned along the fan axis W more centrally between the two lateral sides 14.

It has been found that such a configuration makes it possible to realize the varying along of the discharge volume flow rate ratio V/R in a particularly effective and robust manner without mechanical variation of the discharge assembly 7 and without use of control engineering. Without wishing to be bound by any theory, it is considered that an outflow profile of a centrifugal fan 4 along the fan axis W varies in form, depending on the motor power, and/or, in this case, the total discharge volume flow rate, in particular varying between a mainly off-central outflow at a low motor power and a mainly central outflow at a high motor power. Thus, an inherent property of a centrifugal fan 4 that is normally left unutilized can be utilized with advantage in the context of the present invention, in particular when the separation of the streams F9 and F10 takes place directly downstream of the fan 4, that is, where the outflow profile of the fan

4 is not yet, or hardly so, deformed by interaction with downstream structures such as channels.

In embodiments, the at least one separating element 13 comprises at least two separating elements 13 which are placed along the fan axis W, spaced apart and between the two lateral sides 14 of the fan housing outlet

5 to determine between the separating elements 13 the stream F9 through the ventilation outlet 9 and to determine outside of them the at least one stream F10 through the at least one recirculation outlet 10. Thus, the separation assembly 12 can be configured substantially symmetrically, at least such that along the fan axis W on both sides of the stream F9 through the ventilation outlet 9 a respective stream F 10 to a recirculation outlet 10 is determined, which can be advantageous in particular in combination with a substantially symmetrical configuration of the fan 4, at least when on both sides of the fan 4 a respective fan housing inlet 6 is provided as can be seen in Fig. 6A.

The separation elements 13 in the example shown are implemented as controllable valves, as is further explained elsewhere herein with reference to Fig. 6B in which a full-recirculation position is shown which is different from the combination work position of Fig. 6A. While the discharge assembly 7 can thus comprise one or more valves 13, the above-mentioned automatic varying along of the discharge volume flow rate ratio V/R takes place without any movement of these valves: the separating elements 13 always retain a fixed position during use in the combination work position. Instead of being implemented as valves, the separating elements 13 may hence, if desired, also be simply implemented as baffles, although implementation as valves provides additional advantages, as set out elsewhere herein.

In embodiments, the at least one separating element 13 extends substantially parallel to the fluid stream coming from the fan 4. Thus, influencing of the outflow profile of the fan 4 by the at least one separating element can be limited. In this context, ‘substantially parallel’ can be understood as an angle including at most five degrees, preferably at most three degrees. The fluid stream coming from the fan 4 is, in the case of a centrifugal fan 4, usually directed substantially at right angles to the fan axis W.

In embodiments, the at least one separating element 13 extends to a point directly adjacent to the fan 4, without making contact with the fan 4. In this way, the above-mentioned effect of use of a variable outflow profile of the fan 4 can be utilized to a particularly high degree.

In embodiments, the at least one separating element 13 extends at least partly into the fan housing outlet 5. In this way, the at least one separating element 13 can extend to a point directly adjacent to the fan 4, also when the fan housing outlet 5, as is customary, extends up to some distance from the fan 4.

In embodiments, the at least one separating element 13 is adjustable between the combination work position (shown in Fig. 6A) and a full-recirculation position (shown in Fig. 6B), wherein the at least one separating element 13 in the full-recirculation position blocks the stream F9 through the ventilation outlet 9 and releases the at least one stream F 10 through the at least one recirculation outlet 10, so that the stream F5 through the fan housing outlet 5 in the full-recirculation position is fully passed on to the at least one recirculation outlet 10. Such a full-recirculation position can for instance be used for after-rotating or after-running, that is, for additional air cleaning in the inside environment IE for some time after the cooker 2 has been used. In Fig. 6B it can be seen that the separating elements 13 in this position block the ventilation outlet 9 and split up the stream F5 through the fan housing outlet 5 into two streams F10 to the recirculation outlets 10. Alternatively or additionally, for closing off the ventilation outlet 9, one or more separate closing means such as valves may be provided.

According to a further possibility, the at least one separating element 13 may be adjustable to a full-ventilation position (not shown), which, in effect, is an inverted position compared with the full-recirculation position. In such a full-ventilation position, thus, the fluid flow F9 to the ventilation outlet 9 is released while the fluid flow F10 to the recirculation outlet 10 is blocked. Such a full-ventilation position can for instance be utilized to dissipate excessive heat to the open-air environment OE.

In embodiments, a work position of a fan 4-facing end of the at least one separating element 13 with respect to the fan housing outlet 5 is settable, at least when the extractor assembly 1 is not in operation, for settable influencing of the discharge volume flow rate ratio V/R supplementary to having the discharge volume flow rate ratio V/R automatically vary along with the total discharge volume flow rate V+R. In this way, the relation herein described with reference to Figs. 7 A and 7B between motor power level and discharge volume flow rate ratio V/R can be at least partly set. With the separating elements 13 positioned as in Fig. 6A, the relation mentioned is for instance as shown in Fig. 7 A. By presently setting the work position mentioned so as to place the ends of the separating elements 13 slightly further apart compared with Fig. 6A, the relation can for instance be set as shown in Fig. 7B, whereby the discharge volume flow rate ratio V/R thus is generally increased a bit, while the described automatic varying along as such is maintained. The work position mentioned may for instance be settable through corresponding setting of a servo motor which can for instance also adjust the separating element 13 between the combination work position and one or more other positions such as the full-recirculation position.

Figs. 6A, 7 A and 7B thus illustrate a corresponding method for adjusting a ventilation/recirculation discharge volume flow rate ratio in the extractor assembly 1, comprising: providing the extractor assembly 1 wherein the work position of the fan 4-facing end of the at least one separating element 13 with respect to the fan housing outlet 5 is settable as described; and changing the setting of the work position of the fan 4-facing end of the at least one separating element 13 with respect to the fan housing outlet 5, for adjustment of the discharge volume flow rate ratio V/R supplementary to having the discharge volume flow rate ratio V/R automatically vary along with the total discharge volume flow rate V+R. It will be clear that the method as described here applies only to embodiments of the extractor assembly where the work position mentioned is settable, and that in alternative embodiments of the extractor assembly the work position mentioned is not settable, so that the above-mentioned relation between motor power level and discharge volume flow rate ratio then is, for instance, a fixed relation, so, for instance, either a fixed relation according to Fig. 7 A, or a fixed relation according to Fig. 7B, or another fixed relation.

In embodiments, the cooker arrangement 19 further comprises a ventilation inlet 20, for instance as shown in Fig. 2 behind the cooker 2, to enable the discharge via the ventilation outlet 9 to be balanced with a corresponding intake of fresh outside air in the form of a stream F20 through the ventilation inlet 20. Such a ventilation inlet 20 is preferably provided with a valve, for example a servo valve, with which the inlet 20 can be closed off if no stream through the ventilation outlet 9 is being generated, for instance automatically depending on an operation of the extractor assembly 1. While the invention has herein been further explained on the basis of examples of embodiments and drawings, these do not constitute any limitation of the scope of the invention as defined in the claims. A skilled person having the benefit of the current disclosure will readily appreciate that within that scope many variations, extensions and combinations are possible. Examples thereof have been given in the description.

LIST OF REFERENCE SIGNS

1. Extractor assembly

2. Domestic cooker

3. Fan housing

4. Motorized fan

5. Fan housing outlet

6. Fan housing inlet

7. Discharge assembly

8. Discharge assembly inlet

9. Ventilation outlet

10. Recirculation outlet

11. Recirculation filter

12. Separation assembly

13. Separating element

14. Lateral side of fan housing outlet

15. Recirculation channel

16. Hood

17. Extraction space

18. Sidewall of hood

19. Cooker arrangement

20. Ventilation inlet

F5. Stream through fan housing outlet

F6. Stream through fan housing inlet

F9. Stream through ventilation outlet

F10. Stream through recirculation outlet

F20. Stream through ventilation inlet

IE. Inside environment

OE. Open-air environment

W. Fan axis