EP1209420B1 - Steam vent for steam cooking oven - Google Patents

Description

The present invention relates to a steam evacuation device for a steam cooking oven.

In a steam oven, having an oven chamber, the latter is generally brought to saturation in water vapor at atmospheric pressure by sending water on a heating element in the chamber. The cooking of food is then in this furnace chamber saturated with water vapor.

Some ovens of this type do not have a system to evacuate the steam at the end of cooking. As a result, when the door is opened, a large amount of steam comes out suddenly from the furnace chamber and is released into the room in which it is placed. This causes inconvenience to the user and can even be dangerous (burns). In addition, any damage may be caused to the surroundings by the release of steam (walls, ceiling, etc ...).

EP 0 624 759 discloses a steam cooking oven equipped with a steam evacuation device. This oven comprises a device for the gradual evacuation of the steam produced inside the furnace chamber when the latter is in operation. This evacuation device is triggered by means of control means before the end of cooking. It comprises an opening made in a wall of the enclosure cooperating with a valve which, in a first position, closes this opening and, in a second position, is remote from the latter, thus allowing the evacuation of the steam. A ventilation turbine is possibly used to accelerate the speed of leaving the steam out of the oven enclosure.

This device of the prior art requires the use of an air guide to the outside to drive water vapor from the furnace chamber to the outside of the furnace. This guide must be waterproof to control the flow of steam. A complex system of joints must therefore be implemented to ensure this seal. In addition, the turbine used allows the suction of water vapor in the furnace chamber but causes a rapid drop in temperature and the cooked food is non-uniformly cooled. This can even cause in some cases a deterioration of cooking quality.

EP-A-319 673 discloses the preamble of claim 1.

The present invention aims to provide a steam evacuation device in an improved steam cooking oven. This device will preferably allow a good evacuation of water vapor without cooling too brutally food, nor degrade the qualities of cooking.

For this purpose, the device that it proposes is a device for evacuating steam from an enclosure of a steam cooking oven which comprises means making it possible to send fresh air into the enclosure of the oven by at least one opening and at least one outlet remote from the air inlet for the evacuation of steam from the enclosure, means being provided to control the sending of fresh air into the enclosure of the oven and opening and closing the output to the number of at least one. Fresh air is guided into a duct from an inlet, close to the outlet at least one, until an opening in the furnace chamber for sending fresh air, and a flapper is provided for controlling the simultaneous opening and closing of the inlet of the duct and the at least one steam outlet.

Thus fresh air can be injected into the furnace chamber and the steam in it at the end of cooking can escape through the outlets. When the oven chamber is then open to remove cooked food, there is no risk of burning as there is no more steam in the oven.

For a better evacuation of the steam, the fresh air inlet is advantageously separated from the outlet to the number of at least one. A distance of at least 10 cm advantageously separates the air inlet at each steam outlet.

In a preferred embodiment, the oven enclosure is closed by a door and fresh air is sent into the enclosure near the door. Even if all the steam is not yet evacuated when opening the door, fresh air is at the level of it and the risk of burns are then very limited. In addition, fresh air is injected into an area where there is usually no food. These are therefore not cooled suddenly.

In this embodiment, the duct is advantageously placed outside the enclosure of the furnace and the inlet is preferably disposed on a face of the enclosure of the furnace opposite to the face of the enclosure equipped with the door .

Two or more steam outlets are preferably provided, these outlets being for example distributed on either side of the duct inlet.

Advantageously, at least one outlet has a leak in the closed position of the corresponding opening and closing means. In this way, it is not necessary to provide additional means (eg security slot) to prevent overpressure in the oven enclosure.

Fresh air is injected into the oven chamber, for example using a fan. The latter is advantageously arranged in such a way that it also promotes the extraction of steam by the at least one outlet. Steam ovens usually already have a fan to cool the electrical and electronic components needed for power supply and oven control. This same fan can be used at the end of the cooking process to evacuate the steam out of the oven. Thus during cooking the fan provides cooling components and at the end of cooking it also allows the evacuation of steam outside the enclosure of the oven.

The present invention also relates to a steam cooking oven, characterized in that it is equipped with a steam evacuation device as described above.

• Figure 1 est une vue schématique en vue de côté d'un four de cuisson à la vapeur équipé d'un dispositif d'évacuation de vapeur selon l'invention,
• Figure 2 est une vue correspondant à la figure 1, lors de l'évacuation de la vapeur,
• Figure 3 est une vue de l'arrière du four de cuisson représenté sur les figures 1 et 2,
• Figure 4 est une vue en coupe à échelle agrandie selon la ligne de coupe IV-IV de la figure 3, et
• Figure 5 est une vue en perspective de l'arrière du four représenté schématiquement sur les figures 1 à 3.

Details and advantages of the invention will emerge more clearly from the description given hereinafter with reference to the appended schematic drawing in which:

• Figure 1 is a schematic side view of a steam cooking oven equipped with a steam evacuation device according to the invention,
• Figure 2 is a view corresponding to Figure 1, during the evacuation of steam,
• Figure 3 is a rear view of the baking oven shown on the Figures 1 and 2,
• Figure 4 is an enlarged sectional view along section line IV-IV of Figure 3, and
• Figure 5 is a perspective view of the rear of the oven shown schematically in Figures 1 to 3.

The drawing schematically represents a steam cooking oven which conventionally comprises an enclosure 2 of substantially parallelepipedal shape comprising an upper wall 4, a lower wall 6, three side walls 8 and a door 10. The latter is intended for a part to seal the enclosure 2 and secondly to allow the introduction and withdrawal of food in this chamber.

The enclosure 2 of the furnace is intended to be brought to saturation in water vapor at atmospheric pressure by sending water on a heating element 12 located in the chamber 2. The sealing of the cooking chamber must then be controlled so as not to have a leak of water or steam on pain of not being able to saturate the enclosure and thus ensure a good quality of cooking food placed in the oven. However, means are also provided to prevent pressurization of the enclosure of the furnace. During cooking, a water injection device 14 can send from time to time amounts of water on the heating element 12 to maintain saturation in the chamber 2. This heating element 12 and the injection device of water 14 are of the same type as those commonly used in steam cooking ovens. They are therefore known to those skilled in the art and will not be described in detail here.

The oven shown in the drawing is also equipped with a device for carrying out the evacuation of the steam in the chamber 2 of the oven. This device comprises in particular a fan 16, a valve 18 actuated by a jack 20 and a channel 22.

The fan 16 is a so-called tangential fan comprising a turbine rotating about an axis. The air enters axially into this fan and leaves it tangentially. The fan is disposed at the rear of the furnace, that is to say along the side wall 8 opposite the door 10 and outside the enclosure 2. Its outlet 24 is substantially parallel to the upper walls. 4 and lower 6 of the chamber 2 and is directed upwards. This output extends over a large part of the length of the corresponding side wall 8. Openings 17 made at the rear of the oven are provided for the air supply of the fan 16.

The fan 16 is intended first of all to ensure the cooling of electronic and electrical components intended for feeding and controlling the steam cooking oven. This fan 16 operates during all cooking food placed inside the chamber 2.

The channel 22 is disposed on the upper wall 4 and connects the rear of the oven to the front thereof. This channel has an air inlet 26 and a fresh air outlet 28. The inlet 26 is disposed above the outlet 24 of the fan 16 and the fresh air outlet 28 is close to the door 10 and allows the air flowing in the channel 22 to exit into the chamber 2.

The channel 22 is for example made by producing in the upper wall 4 of the enclosure 2 a groove extending from the rear side wall 8 towards the door 10, for example in the median position, and by fitting in this groove a profile made of U of slightly shorter length to the groove so as to make the side of the door 10 the outlet of fresh air 28.

The valve 18 controls the opening and closing of fresh air inlet 26 in the closed position of the valve, the air leaving the fan 16 can not enter the channel 22. In the open position of the valve, this fresh air can enter the channel 22 and the valve 18 plays a deflector role promoting the introduction of air into the channel 22. Figure 4, showing the valve 18 only at the inlet 26 in the open position, illustrates how the fresh air passes from the outlet 24 of the fan 16 to channel 22.

The valve 18, at the same time as it controls the opening and closing of the fresh air inlet 26, also controls the opening and closing of steam outlets 30. These are located on the side wall 8 rear of the enclosure, on either side of the fresh air inlet 26. In the embodiment shown in the drawing, two outlets 30 are provided on each side of the inlet 26. At the level of the rear wall, the inlet 26 of fresh air is disposed just above the plane of the upper wall 4. The steam outlets 30 are arranged just below the level of the upper wall 4 and the outlet 24 of the fan 16 is disposed at a still lower level.

The closure of the steam outlets 30 by the valve 18 is not waterproof. In this way, it is possible to avoid the occurrence of overpressure in the chamber 2 without having to provide other openings in the enclosure. Of course, the leakage at the steam outlets 30 is controlled in the closed position of the valve 18.

Figures 3 and 5 show the shape of the valve 18. The latter comprises a horizontal cross member 32 and a vertical bar 34. The horizontal cross member 32 is provided for closing the fresh air inlet 26 and the steam outlets 30 The vertical bar 34 controls the movement of the horizontal crossbar 32. It connects the crosspiece 32 to the cylinder 20.

The steam outlets are upwardly oriented. To achieve this orientation, they are made in an ear protruding from the rear side wall 8. In order to be able to substantially close off these outlets 30, the horizontal cross member 32 of the valve 18 has, for each outlet 30, a housing of suitable shape. Here, this housing has a shape of a circular half-cylinder of low height reminiscent of a half-moon.

The valve 18 is articulated around a horizontal axis 36. This axis is is located substantially at the upper edge of the channel 22, the side of the inlet 26.

The upper portion of the vertical bar 34 of the valve member 18 is in the embodiment shown in the drawing as a fork with a central slot. The latter is intended to allow the connection between the free end of a sliding cylinder rod and the valve 18. The cylinder 20 used here is for example an electrically controlled wax cylinder. The rod of this actuator acts perpendicular to the horizontal axis 36 thus allowing the valve 18 to pivot about this axis.

The operation of the oven is then the following. After placing food in the chamber 2, the door 10 is closed and the chamber of the furnace is brought to saturation in water vapor at atmospheric pressure by sending water on the heating element 12. During this phase of preheating, the valve 18 is in the closed position. The enclosure 2 is thus sealed, only the overpressure safety at the outlets 30 being provided. During the cooking phase, successive water sends maintain saturation in the chamber 2. The valve 18 remains then in the closed position and the enclosure also remains. At the end of cooking, the chamber 2 is saturated with water vapor at 100 ° C. To avoid any risk of burns when opening the door, burns caused by the steam leaving the chamber 2, the steam evacuation device described above is activated a few minutes before the end of cooking. The valve 18 opens thus enabling fresh air to be introduced into the chamber 2 and the steam outlet via the outlets 30. As indicated above, the valve in the open position acts as a deflector favoring the introduction of fresh air leaving the fan 16 in the channel 22. This air exits the channel through the outlet 28 and creates a slight pressure inside the chamber 2 thus expelling the water vapor in it. The only possibility for the steam is to exit through the outlets 30, the channel 22 being in overpressure. As indicated above, the outlets 30 are oriented upwards. The air flow leaving the fan 16 is also directed upwards. Thus, the flow of fresh air carries with it the steam leaving the chamber 2. In this way, the steam outlet is favored and the mixture of this steam to fresh air immediately out allows a cooling of this water vapor thus preventing any risk of burns. As is apparent from the foregoing, the outlets 30 are preferably above the outlet 24 of the blower 16. To regulate the mixture of fresh air and steam, deflectors 38 may be provided between the outlet 24 of the blower 16 and the steam outlets 30.

After a valve opening time, calculated according to fresh air inlet and steam outlet flow rates and enclosure volume, the oven door can be opened safely.

With this device and this cooking process, the chamber 2 of the oven can be emptied of water vapor in a relatively short time (less than 3 minutes) for the greatest safety and for the comfort of the user. This device also prevents the discharge of hot steam outside the oven to prevent damage to eg level ceilings or surrounding walls. The hot steam does not circulate in the oven either outside the enclosure. The steam coming out of the oven is immediately mixed with fresh air. This water vapor is expelled, not sucked in, so that the steam does not enter the fan. This allows the fan to work in good conditions guaranteeing a longer life.

In addition, as shown by tests carried out, the food placed in the oven enclosure is not cooled too quickly during the evacuation of steam and no degradation of the cooking qualities could be observed.

To best guarantee all these advantages, it is preferable to have the fresh air outlet at the remote enclosure, for example at least 10 cm, the steam out of the enclosure. Preferably, for reasons of safety, the fresh air is sent to the side of the door of the enclosure 2. Thus, this door is cooled in priority and the steam in the vicinity of this door is replaced very quickly by the air is less hot and unsaturated. An accidental opening of the door before the end of the evacuation phase of the water vapor is then less dangerous for a user.

The invention is not limited to the preferred embodiment described above by way of non-limiting example. It encompasses all variants embodiment within the scope of those skilled in the art within the scope of the claims below.

Thus, the arrangement of the valve, the fan, can be modified without departing from the scope of the invention. A separate fan can be provided for fresh air injection and cooling of the electronic and electrical components of the furnace. A separate valve can be provided for the fresh air inlet and the steam outlet.

The control means of the valve may be different. The wax jack can be replaced by any means such as an electromagnet, an electric actuator, etc.

The presence of a channel guiding the fresh air before its injection into the enclosure of the oven is optional. In the case of the presence of such a channel, its implementation can be achieved by any means and not only as described above.

In the foregoing description, there is only one fresh air inlet in the furnace enclosure and several steam outlets. Of course, it is possible to have several air intakes and / or a single steam outlet. All cases can be considered.

Claims (7)

1. Device for discharging steam out of the enclosure (2) of a steam cooking oven, comprising means (16) for sending pressure into the enclosure (2) of the oven through at least one opening (28) and at least one outlet (30) remote from the inlet (28) for discharging steam out of the enclosure, means (18, 20) being provided for controlling the sending of pressure into the oven enclosure and the opening and closing of the at least one outlet (30), characterised in that the fresh air is guided in a conduit (22) from an inlet (26) close to the at least one outlet (30), as far as an opening (28) formed in the oven enclosure for sending fresh air, and in that a valve (18) is provided for controlling the opening and closing simultaneously of the inlet (26) to the conduit and the at least one steam outlet (30).
2. Steam discharge device according to claim 1, characterised in that the oven enclosure (2) is closed by a door (10) and in that the fresh air is sent into the enclosure (2) close to the door (10).
3. Steam discharge device according to claim 2, characterised in that the conduit (22) is placed outside the enclosure (2) of the oven and in that the inlet (26) is disposed on one face of the oven enclosure opposite to the face of the enclosure equipped with the door (10).
4. Steam discharge device according to one of claims 1 to 3, characterised in that at least one outlet (30) has a leakage in the closed position of the corresponding opening and closing means (18, 20).
5. Steam discharge device according to one of claims 1 to 4, characterised in that the fresh air is injected into the oven enclosure (2) by means of a fan (16).
6. Steam discharge device according to claim 5, characterised in that the fan (16) is disposed so that it also assists the extraction of steam through the at least one outlet (30).
7. Steam cooking oven, characterised in that it is equipped with a steam discharge device according to one of claims 1 to 6.

Images