HUMIDITY FLUSHING SYSTEM

Abstract

A kitchen appliance (1) comprising at least one first fan (15) and a cavity (2), wherein said cavity (2) comprises at least one outlet opening (3) for exhaustion of vapor and/or steam out of the cavity (2) into a first duct (4), wherein said first duct (4) can be opened or closed by a first valve (5), and at least one inlet opening (6) for influx of air into the cavity (2) from a second duct (7), wherein said second duct (7) can be opened or closed by a second valve (8), wherein said first duct (4), particularly said first valve (5), is configured such that in an open stage of said first valve (5) said exhaustion of vapor and/or steam out of at least one outlet opening (3) of the cavity (2) into said first duct (4) is substantially due to an overpressure of vapor and/or steam within said cavity (2), and wherein said second duct (7), particularly said second valve (8), is configured such that in an open state of said second valve (8) said influx of air into at least one inlet opening (6) of the cavity (2) from said second duct (7) is substantially due to an overpressure of said air generated in said second duct (7), preferably by said at least one first fan (15).

Claims

1. A kitchen appliance comprising at least one first fan and a cavity, wherein said cavity comprises at least one outlet opening for exhaustion of vapor and/or steam out of the cavity into a first duct, wherein said first duct can be opened or closed by a first valve, and at least one inlet opening for influx of air into the cavity from a second duct, wherein said second duct can be opened or closed by a second valve, wherein said first duct, and said first valve are configured such that in an open stage of said first valve said exhaustion of vapor and/or steam out of at least one outlet opening of the cavity into said first duct is substantially due to an overpressure of vapor and/or steam within said cavity, and wherein said second duct and said second valve are configured such that in an open state of said second valve said influx of air into at least one inlet opening of the cavity from said second duct is substantially due to an overpressure of said air generated in said second duct.

2. The kitchen appliance according to claim 1, wherein kitchen appliance comprises a cooling system, and wherein the first duct is in fluid communication with the cooling system.

3. The kitchen appliance according to claim 1, wherein the kitchen appliance comprises a cooling system, and wherein the second duct is in fluid communication with the cooling system.

4. The kitchen appliance according to claim 1, wherein the first valve and/or the second valve is a throttle valve.

5. The kitchen appliance according to claim 1, wherein the cavity and the cooling system are configured as an open system.

6. The kitchen appliance according to claim 1, wherein the first valve and/or the second valve is an electric valve.

7. The kitchen appliance according to claim 1, wherein the kitchen appliance comprises a humidity sensor capable of monitoring the humidity within the cavity, wherein said humidity sensor is connected to a control unit capable of controlling the first valve and/or the second valve.

8. The kitchen appliance according to claim 1, wherein the outlet opening is arranged in an upper wall of the cavity.

9. The kitchen appliance according to claim 1, wherein the inlet opening is arranged in a bottom wall and/or a side wall of the cavity.

10. The kitchen appliance according to claim 2, wherein the cooling system comprises said first fan.

11. The kitchen appliance according to claim 2, wherein the first duct is arranged such that its first end is in fluid communication with the cavity at said at least one outlet opening, and its second end is in fluid communication with said cooling system, and/or wherein the second duct is arranged such that its first end is in fluid communication with the cavity at said at least one inlet opening, and its second end is in fluid communication with said cooling system.

12. The kitchen appliance according to claim 2, wherein a second end of the first duct is arranged in an under pressure region of said cooling system.

13. The kitchen appliance according to-claim 2, wherein a second end of the second duct is arranged in an over pressure region of said cooling system.

14. The kitchen appliance according to claim 1, the kitchen appliance comprising at least one second fan.

15. The kitchen appliance according to claim 1, wherein in a state wherein the first valve is arranged in a closed state and the second valve is arranged in a closed state steam and/or vapor within the cavity is preserved within the cavity, and/or in a state wherein the first valve is arranged in an open state and the second valve is arranged in a closed state steam and/or vapor exhausts out of the outlet opening, and/or in a state wherein the first valve is arranged in an open state and the second valve is arranged in an open state steam and/or vapor within the cavity exhausts out of the at least one outlet opening and is replaced and/or displaced by air, which enters the cavity by an air influx into the cavity from the second duct.

16. The kitchen appliance according to claim 1, said overpressure of said air generated in said second duct being produced by said at least one first fan.

17. The kitchen appliance according to claim 10, said cooling system comprising a cooling chamber, said first fan being arranged in said cooling chamber.

18. The kitchen appliance according to claim 13, said cooling system comprising a cooling chamber, said first fan being arranged in said cooling chamber, wherein the second end of the second duct is arranged in an over pressure region of said first fan.

19. A kitchen appliance comprising a cooking cavity and a cooling chamber, the cooking cavity having an outlet opening in an upper wall thereof and an inlet opening in another wall thereof, said outlet opening being in fluid communication with an underpressure region of said cooling chamber via a first flow path having a first valve and said inlet opening being in fluid communication with an overpressure region of said cooling chamber via a second flow path having a second valve, said second flow path having a smaller cross-section than said first flow path, a cooling fan disposed in said cooling chamber and effective to generate an underpressure in said underpressure region and an overpressure in said overpressure region, said cooling fan being further effective to generate a flow of cooling air for the appliance, a controller operatively coupled to each of said first and second valves and configured to operate them so that: in a first mode the first valve is opened and the second valve is closed thus allowing pressurized steam and/or vapor in said cooking cavity to be exhausted therefrom into said cooling chamber; in a second mode both the first and second valves are closed thereby maintaining in said cooking cavity the steam and/or vapor therein; and in a third mode both the first and second valves are opened thereby flushing said cooking cavity by exhausting steam and/or vapor therefrom into said cooling chamber where the steam and/or vapor will be mixed with said flow of cooling air, and introducing dryer and/or cooler air, relative to said steam and/or vapor, into said cooking cavity via said inlet opening.

20. The kitchen appliance of claim 19, further comprising a second fan, smaller than said cooling fan, in fluid communication with said second flow path and effective to generate or support overpressure therein, and an air intake coupled to said second fan configured to permit said second fan to draw outside air from outside said cooling system in order to generate or support said overpressure in said second air flow path, said controller being configured to operate said appliance according to a cooking cycle comprising a plurality of phases corresponding to said first, second and third modes.

Description

[0127] The present invention will be described in further detail with reference to the drawings from which further features, embodiments and advantages may be taken, and in which

[0128] FIG. 1, FIG. 2A and FIG. 2B illustrate perspective views of a kitchen appliance according to the present invention showing the first inventive embodiment;

[0129] FIG. 3 illustrates a schematic diagram of a Humidity flushing system for a kitchen appliance according to the present invention showing the first inventive embodiment;

[0130] FIG. 4A and FIG. 4B illustrate perspective views of a kitchen appliance according to the present invention showing a second inventive embodiment; and

[0131] FIG. 5 illustrates a schematic diagram of a Humidity flushing system for a kitchen appliance according to the present invention showing the second inventive embodiment.

[0132] FIGS. 1, 2A and 2B show a kitchen appliance 1 according to a first inventive embodiment of the present invention, here a steam oven, which comprises a cavity 2, wherein said cavity 2 comprises at least one outlet opening 3 for exhaustion of vapor and/or steam out of the cavity 2 into a first duct 4, wherein said first duct 4 can be opened or closed by a first valve 5, and at least one inlet opening 6 for influx of air A into the cavity 2 from a second duct 7, wherein said second duct 7 can be opened or closed by a second valve 8. Advantageously said outlet opening 3 is positioned in an upper wall 12 of said cavity 2. The first valve 5 according to the first embodiment is not shown in the FIGS. 1, 2A and 2B, as it is preferably arranged within the first duct 4.

[0133] As may be seen from FIG. 2A or 4A a further fan element 23 may be positioned within the cavity 2, being, for example, a central cooking fan 23 positioned in the back wall of the cavity 2.

[0134] Such additional fan element 23 may not be or at least not substantially be related with cooling. In the shown embodiment said further fan element 23 is a central cooking fan 23, meant to generate a forced convection inside the cavity 2, to enhance cooking process. The effect of such further fan element 23, particularly of such cooking fan 23, may not be for generating a flushing effect according to the present invention. However, a person skilled in the art will know to position the elements of the flushing system according to the present invention if such further elements, particularly such further fan element 23 is present. For example, the positioning and arrangement of an inlet opening 6 for flushing airflow advantageously may be selected such that negative interactions with the air or steam/vapor flow of such cooking fan 23 are avoided. For example, it may be of advantage to position and arrange an inlet opening 6 with sufficient distance to the areas where convection flow speed is high.

[0135] As may be also seen from FIG. 2A or 4A further the kitchen appliance 1 and, particularly the cavity 2 of such kitchen appliance 1 may comprise further elements generally known to the person skilled in the art. For example, side rails 24 may be provided in the cavity, particularly on an inner sidewall of the cavity in order to support a baking tray or grid.

[0136] Such steam oven 1 advantageously provides an enhanced steam exhaust system to ensure an improved steam evacuation from the oven cavity 2. A more effective removal/reduction of the steam and/or vapor S contained within the cavity 2 during a cooking cycle is enhanced and an exhaustion of the vapor and/or steam through an opened door is reduced. Moreover, steam and/or vapor S are more effectively be drained and exhausted from the appliance cavity 2, particularly when vapor and/or steam is in excess for the running cooking cycle.

[0137] Said second duct 7 can be opened or closed by a second valve 8, which can be opened or closed coordinated with said first valve 5, which is for opening or closing at least one outlet opening 3 for exhaustion of vapor and/or steam out of the cavity 2 into said first duct 4. Such exhaustion advantageously takes place if the vapor and/or steam in the cavity has an overpressure. The second valve 8 can be advantageously operated along with the first valve 5, to achieve a washing effect such that, preferably steam and/or vapor S within the cavity exhausts out of the outlet opening 3 and is replaced and/or displaced by air A, which enters the cavity 2 by an air A influx into the cavity 2 from the second duct 7. Thus, the steam and/or vapor S within the cavity is replaced and/or displaced.

[0138] Such washing and/or flushing preferably is mainly due to a psychrometric effect, i.e. by injecting a relatively small quantity of influx air A, preferably fresh air, more preferably relatively dry and/or cold fresh air, preferably ambient air. A person skilled in the art will immediately understand that this will affect air title inside the cavity 2 with a limited impact on temperature in the oven 1 and/or cavity 2. In connection therewith, it is to be understood that a more massive flushing flow would actually abate oven temperature, wasting at the same time energy, and temperature would have to be recovered.

[0139] Here, the steam oven 1 comprises a cooling system 9 comprising a cooling chamber 10. The cooling chamber 10 and the cooling system 9 are positioned on top of the upper cavity wall 12. The first duct 4 is in fluid communication with the cooling system 9, preferably the cooling chamber 10 and the second duct 7 is in fluid communication with the cooling system 9, more particularly, with the cooling chamber 10. Additionally, the first valve 5 and the second valve 8 both are configured as electric throttle valves, which allow a restriction and narrowing of the flux adjustable by said valve, and particularly allow for a targeted and selective control of different valve states, e.g. opened or closed, particularly by a not shown oven control unit. Such electronic valve is also advantageous in ensuring a proper opening/closing of the valves 5 and/or 8 and thus the regulation of an airflow A and/or steam and/or vapor flow S through the respective first duct 4 or second duct 7, respectively.

[0140] Moreover, it can be immediately seen that the cavity 2 and the cooling system 9 are configured as an open system, wherein the second valve 8 is operated along with the first valve 5 to achieve a “washing” effect of the cavity, i.e. a relatively small amount of relatively dry air A when introduced in the cavity 2 can absorb a significant amount of humidity, as it reduces the overall humidity title of the air A in the cavity 2. Furthermore, the cavity 2 is not designed as a strictly closed system, and a significant flow out of the exhaust can be achieved.

[0141] The steam oven 1 according to the shown embodiment comprises a not shown humidity sensor 11, capable of monitoring the humidity within the cavity 2, wherein, preferably said humidity sensor 11 is connected to an also not shown control unit, capable of controlling the first valve 5 and/or the second valve 8.

[0142] As may be taken from the schematic diagram of FIG. 3 and from FIG. 2A the outlet opening 3 may be arranged in an upper wall 12 of the cavity 2 and the inlet opening 6 may be arranged in a bottom wall 13 of the cavity 2.

[0143] This is of particular advantage in that the hot or warm air A, steam and/or vapor S accumulates in an upper region of said cavity 2 due to physical laws of convection. Accordingly, an exhaust of steam and/or vapor, usually being warm or hot is facilitated when the outlet opening 3 is arranged in such upper region, particularly in an upper wall 12 of the cavity 2 or an upper part of a sidewall 14 of the cavity 2, and additionally where the inlet opening 6 is arranged in a bottom wall 13 of the cavity 2 or a lower part of a side wall 14 of the cavity 2, this is of particular advantage as the introduced air A is colder than the vapor and/or steam S within the cavity 2, particularly as the introduced air A is air from the cooling system 9, or cooling chamber 10. For the positioning of the inlet opening 6 and/or the outlet opening 3 various configurations may be chosen. However, it is to be understood that a major criteria for the positioning of an inlet opening 6 and/or an outlet opening 3 is to provide a sufficient distance between the inlet opening 6 and the outlet opening 3, as otherwise a fluid dynamic short circuit could be generated, preventing proper flushing of the cavity volume.

[0144] The inventive steam oven 1, more particularly the cooling system 9 and the cooling chamber 10, comprises a first fan 15, preferably a radial or a tangential fan. As may be best seen from FIG. 1 and FIG. 2B the main cooling fan for driving the main cooling flow M may be advantageously used as said first fan 15. Such fan 15 preferably comprises a cochlea. In connection therewith, it is to be understood that a person skilled in the art will choose an advantageous positioning of such first fan 15. Such positioning is not per se crucial and can be chosen according to various needs, if such first fan 15 comprises and/or is surrounded by such cochleae housing, referred to herein as cochlea. Such cochlea is advantageously driving the main air output flow M, preferably used as cooling. Accordingly, any area or region within such cochlea will represent a high air pressure, which can be exploited to create a secondary air flow A entering the second duct 7, without significantly changing the main flow output M, provided that the flow rate of the secondary air flow A in the second duct 7 is significantly lower that the flow rate of the main cooling flow M.

[0145] Such first fan 15 is of particular advantage in driving the air A stream of said cooling and provoking a circulation of such cooling air A stream and thus may contribute and assist an exhaustion of steam and/or vapor S out of the cavity 2 through the first duct 4, particularly, where the first duct 4 is in fluid communication with the cooling system 9, preferably the cooling chamber 10; and/or the first fan 15 may contribute and assist an air A influx into the cavity 2 from a second duct 7, particularly where the second duct 7 is in fluid communication with the cooling system 9, preferably the cooling chamber 10.

[0146] However, it is to be understood that said first duct 4, particularly said first valve 5, is configured such that in an open stage of said first valve 5 said exhaustion of vapor and/or steam out of at least one outlet opening 3 of the cavity 2 into said first duct 4 is substantially due to an overpressure of vapor and/or steam S within said cavity 2, and that said second duct 7, particularly said second valve 8, is configured such that in an open state of said second valve 8 said influx of air A into at least one inlet opening 6 of the cavity 2 into said second duct 7 is substantially due to an overpressure of said air A generated in said second duct, particularly by said at least one first fan 15.

[0147] Here, the first duct 4 is arranged such that its first end 16 is in fluid communication with the cavity 2 at said outlet opening 3, and its second end 17 is in fluid communication with said cooling system 9, more particularly the cooling chamber 10, whereas the second duct 7 is arranged such that its first end 18 is in fluid communication with the cavity 2 at said inlet opening 6, and its second end 19 is in fluid communication with said cooling system 9, more particularly the cooling chamber 10. More particularly, the second end 17 of the first duct 4 is arranged in an under pressure region 20 of said cooling system 9, particularly of said cooling chamber 10 and of said first fan 15.

[0148] This is of particular advantage in that said first duct 4 is advantageously positioned in such under pressure region 20 and due to an injector effect an under pressure within the first duct 4 is generated and thus the vapor and/or steam S is sucked from the cavity 2 out of said cavity 2 and into the first duct 4, from where it enters the cooling system 9, more particularly the cooling chamber 10 and is mixed with the cooling air A. Such effect is supporting the exhaust substantially driven by the overpressure of steam/vapor S within the cavity. The vapor and/or steam S is than, preferably taken away by the cooling airflow A. Here the second end 17 of the first duct 4 is arranged in an under pressure region 20, being an outlet area of a first fan 15, such, that a rotating movement of said first fan 15 supports the sucking of the vapor and/or steam out of the cavity 2 through said first duct 4. The second end 19 of the second duct 7, however, is arranged in an over pressure region 21 of said cooling system 9, particularly of said cooling chamber 10, more particularly of said first fan 15.

[0149] This is of particular advantage in that said second duct 7 is advantageously positioned such that air A from the cooling system 9, particularly a cooling chamber 10, is pressed from such over pressure region 21 into the second end 19 of said second duct 7 and thus the air A is pressed into the cavity 2 through the inlet opening 6 at the first end 18 of said second duct 7. In an advantageous embodiment of the inventive steam oven 1 said second end 19 of the second duct 7 is arranged in such over pressure region 21 being an outlet area of a first fan 15, preferably such, that a rotating movement of said first fan 15 supports the influx of air A into the cavity 2 through said second duct 7.

[0150] In such configuration, a rotating movement of said first fan 15 supports the influx of air A into the cavity 2 from said second duct 7.

[0151] It is important to understand that in a state, wherein the first valve 5 is arranged in a closed state and the second valve 8 is arranged in a closed state steam and/or vapor S within the cavity 2 is preserved within the cavity 2, and in a state, wherein the first valve 5 is arranged in an open state and the second valve 8 is arranged in a closed state and wherein, an overpressure of steam and/or vapor S is within the cavity 2, steam and/or vapor S exhausts out of the outlet opening 3, and in a state, wherein the first valve 5 is arranged in an open state and the second valve 8 is arranged in an open state steam and/or vapor S within the cavity exhausts out of the outlet opening 3 and is replaced and/or displaced by air A, which enters the cavity 2 by an air influx A into the cavity 2 from the second duct 7.

[0152] In FIG. 4A and 4B, as well as in the schematic view of FIG. 5, a second embodiment of the kitchen appliance 1 according to the present invention is shown, which departs from the first embodiment, in that the kitchen appliance 1, particularly the flushing system of said kitchen appliance 1, comprises a second fan 22.

[0153] As may be immediately taken from FIG. 4B such second fan 22 advantageously is configured and positioned such that it generates and supports an overpressure of air in the second duct 7. According to the shown second embodiment of the appliance 1 according to the present invention, the second fan 22 is positioned close to or at a second end 19 of the second duct 17.

[0154] Accordingly, the influx of air into the inlet opening 6 of the cavity 2 from said second duct 7 is substantially due to an overpressure of said air generated in said second duct 7, preferably generated by said at least one first fan 15 and of said at least one second fan 22. Particularly, said second valve 8, is configured such that in an open state of said second valve said influx of air A into the inlet opening 6 of the cavity 2 from said second duct 7 is substantially due to an overpressure of said air A generated in said second duct 7, preferably generated by said at least one first fan 15 and by said at least one second fan 22.

[0155] Such second fan 22 may advantageously be placed in an overpressure region 21 of said first fan 15 in order to generate and assist the at least one first fan 15 in generating an overpressure of said air A in said second duct 7, particularly said influx of air A into the inlet opening 6 of the cavity 2 from said second duct 7.

[0156] In connection with providing such second fan 22 in addition to the at least one first fan 15, it is to be understood that said second fan 22 is provided additionally to the at least one first fan 15. In connection therewith, it is to be understood that the at least one first fan 15 may fulfill primarily the function of a main cooling fan, whereby the at least one second fan 22 is configured and/or positioned such that it substantially supports an overpressure in said second duct 7 generated by said first fan 15, whereby the influx of air A into the inlet opening 6 of the cavity 2 from said second duct 7 is advantageously supported by said at least one second fan 22.

[0157] As may be seen, for example from FIG. 4B, such second fan 22 according to the present invention may be arranged in direct fluid communication with the second duct 7. The second fan 22 may be arranged such that it is capable of generating an overpressure in the second duct 7, preferably alternatively or additionally to the overpressure generated by the first fan 15.

[0158] As shown in FIG. 4B such second fan 22 may be positioned in or connected to the second duct 7. The second fan 22 may be arranged in front of the second valve 8 with regard to the desired flow direction A in the second duct 7, which is depicted by the arrowheads of the respective arrows. However, the second fan 22 may alternatively be arranged subsequent to the second valve 8 with regard to the desired flow direction A in the second duct 7. This may be of particular advantage if it is desired to generate the overpressure in the second duct 7 by the second fan 22 only, particularly independent from the first fan 15. In such state, the second valve 8 may be closed, or at least partially closed, which would lower the contribution of the first fan 15 to the overpressure in the second duct 7. The first fan 15 may then fulfil its main purpose of generating and driving the main cooling flow M, whereby the second fan 22 may still generate an overpressure of airflow A in the second duct 7.

[0159] In an embodiment, the second fan 22 may comprise an air intake 25, e.g. an air intake duct 25, for sucking air into said second fan 22. Such air intake 25 may be configured to allow air intake A from outside of the cooling system alternatively or additionally to the air intake into such second fan from an overpressure region 21 of the first fan 15. Such air intake 25 may be regulated by an additional valve to be in an opened or closed state. Accordingly, the contribution of the second fan 22, as well as the sucking of air from an overpressure region 21 of the first fan 15, may be regulated by the operation, e.g. rotational speed, of said second fan 22, as well as additionally or alternatively by the regulation of the source of air intake, e.g. from the air intake 25 and/or from the from an overpressure region 21 of the first fan 15.

[0160] In both arrangements of the second fan 22, i.e. in front of or subsequent to the second valve 8, said second fan 22 preferably is arranged such that it is capable of generating a flow of air A in the second duct 7, e.g. on an external side of the cochlea of a main cooling fan 15. Preferably, the second fan 22 is arranged and/or positioned in direct connection with the second duct 7.

[0161] Such second fan 22 may thus advantageously enhance the flushing effect of the cavity 2 in “washing” phase. Furthermore, such second fan 22 advantageously prevents an undesired backflow of steam and/or vapor S into the second duct 7 and/or fluid dynamic short circuits.

[0162] In an embodiment, also the second fan 22 may advantageously comprise a cochlea. Furthermore, as may be seen from FIG. 4B such second fan 22, particularly a cochlea housing thereof, may comprise an additional duct for suction of fresh air A into the second fan 22, particularly into its housing. This advantageously allows the second fan 22 to suck fresh, preferably ambient, air A into the second duct 7. This is of particular advantage if the second fan 22 is positioned subsequent to a second valve 8, more particularly if said second valve 8 is in a closed state.

[0163] In an embodiment the first duct 4 and/or the second duct 7, comprises at least one further valve. For example, one second valve 8 may be positioned subsequent to the second fan 22, and one second valve 8 may be additionally positioned in front of said second fan 22.

[0164] As may be best seen from FIG. 4B such second fan 22 is configured smaller than the first fan 15. Such smaller configuration of the second fan 22 compared to the first fan 15 is advantageous as it may be easily arranged and/or placed within the flushing system, according to the present invention, preferably close to or as part of the second duct 7, more preferably at a second end 19 of the second duct 7.

[0165] From FIG. 5 it is also immediately apparent that an overpressure is generated in the second duct 7, particularly in an area of the second valve 8 and/or where the second valve 8 input spills the air A to be driven into the cavity 2. Such overpressure area may be located close to a high-pressure area or over pressure region 21 of the first fan 15 and/or of the second fan 22, e.g.

[0166] the high-pressure area of a cooling radial fan cochlea, and/or at a second end 19 of the second duct 7.

[0167] The features of the present invention disclosed in the specification, the claims, and/or the figures may both, separately and in any combination thereof, be material for realizing the invention in various forms thereof.

LIST OF REFERENCE NUMERALS

[0168] 1 kitchen appliance

[0169] 2 cavity

[0170] 3 outlet opening

[0171] 4 first duct

[0172] 5 first valve

[0173] 6 inlet opening

[0174] 7 second duct

[0175] 8 second valve

[0176] 9 cooling system

[0177] 10 cooling chamber

[0178] 11 humidity sensor

[0179] 12 upper wall of the cavity

[0180] 13 bottom wall of the cavity

[0181] 14 side wall of the cavity

[0182] 15 first fan

[0183] 16 first end of first duct

[0184] 17 second end of first duct

[0185] 18 first end of second duct

[0186] 19 second end of second duct

[0187] 20 under pressure region

[0188] 21 over pressure region

[0189] 22 second auxiliary fan

[0190] 23 fan element inside cavity

[0191] 24 side rails

[0192] 25 air intake

[0193] S steam and/or vapor

[0194] A fresh air/cavity flushing flow

[0195] M main cooling flow