WO2013026812A2

WO2013026812A2 - Improved cooking apparatus

Info

Publication number: WO2013026812A2
Application number: PCT/EP2012/066159
Authority: WO
Inventors: Matjaz ES
Original assignee: Gorenje D.D.
Priority date: 2011-08-22
Filing date: 2012-08-20
Publication date: 2013-02-28
Also published as: WO2013026812A3; DE112012003492T5; SI23848A

Abstract

The present invention refers to a cooking apparatus, particularly to a household cooking apparatus, preferably to a steam oven, and even more preferably to a steam generator generating the steam for preparing food in said steam oven. In a generator body (1) a tubular insert (3) is arranged around which a heater (2) being tightly wound in a thread-like manner. Provided are means (6, 13) to eliminate the water from the steam.

Description

Improved cooking apparatus

The present invention refers to a cooking apparatus, particularly to a household cooking apparatus, preferably to a steam oven, and even more preferably to a steam generator generating the steam for preparing food in said steam oven.

A cooking apparatus, preferably a steam oven with a steam generator is generally known. Said steam generator is heated by means of a heating body, whereupon wet steam is obtained due to intense heating of the liquid, said wet steam comprising a high part of water droplets having a negative effect on the method of the heat treatment of the food.

It is the object of the present invention to create a cooking apparatus of the aforementioned kind which remedies the drawbacks of the known solutions.

According to the present invention, the object as set above is solved with characteristics of the characterising part of the claim 1. Details of the inventions are further disclosed in subclaims.

The invention is further described in detail on the basis of the preferred embodiments, and with a reference to the accompanying drawings, where

Fig. 1 shows a cross-sectional view of the first embodiment of the steam generator according to the invention,

si. 2 shows a cross-sectional view of the second embodiment of the steam generator according to the invention.

Fig. 1 shows a cross-sectional view of a schematically represented first embodiment of a steam generator according to the invention comprising a generator body 1, in which there is arranged a known heater 2 preferably resembling a form of a helix. In order to increase the surface of said heater 2 which is in direct contact with the water to be evaporated, said helix-like heater 2 is tightly wound around a tubular insert 3, the length thereof is preferably at least equal to the length of said heater 2. It is provided for, according to the present invention, that said heater 2 and said insert 3 are mutually connected, preferably by means of hard-soldering so that it can be achieved most efficient heat transmission from the heater 2 to the insert 3. In order to increase the heat efficiency of the generator according to the invention, it is provided for that said heater 2 is enclosed from the outer side thereof with a liner 2', thus increasing substantially the surface being in contact with the liquid. The first end of said tubular insert 3 is attached to a bottom 1' of said generator body 1, whereas the second end of said tubular insert 3, being averted from said bottom 1', remains free. Furthermore, an inlet extension 4 and an outlet extension 5 are attached to said generator body 1 at the exterior thereof. Said inlet extension 4 which is intended to supply the water into the generator body 1 penetrates said bottom 1' and is located outside the connection area of said tubular insert 3 and the bottom 1', so that the water to be evaporated can freely flows to said generator body 1. Said outlet extension 5 which is intended to evacuate the steam from the generator body 1 penetrates said bottom 1' and is located within the connection area of said tubular insert 3 and the bottom 1', so that the steam can freely exits said generator body 1.

The water which flows to generator body 1 via said inlet extension 4 (arrow A) runs around said heater 2 and said tubular insert 3 on the outside thereof. The water evaporates on the contact with said heater 2 and a wet steam is developed. Said wet steam is lead through said insert 3 (arrow B) where said wet steam is additionally heated, and in order to develop a dry steam which in turn is forwarded from said insert 3 via said outlet extension 5 (arrow C) as much energy as possible is transferred from the heater 2 to said wet steam. Using the steam generator according to the invention, the amount of the dry steam increases substantially, thus resulting in a higher energy which is received during condensation of the steam by the surface of the food to be treated.

Fig. 2 shows a cross-sectional view of a schematically represented second embodiment of the steam generator according to the invention, which differs from the above described first embodiment in that it provides additional steps in order to additionally heat the wet steam developing in the contact of the water with the heater 2. According to the invention, one of said steps provides for that from the steam being forwarded to the food to be treated, it is eliminated as much water as possible so that the steam becomes as dry as possible. Therefore, a water trap 6 is associated with the free end of said tubular insert 3, said water trap 6 consisting of a dome-like guide 7 and a barrier 8. Said dome-like guide 7 is located directly at the mouth of the free end of said insert 3 and entirely covers the latter. Said guide 7 is formed at the side of the steam generator according to the invention to which the water is supplied via said inlet extension 4, with an entrance 9 through which it is allowed the steam to enter the guide 7 and further the said tubular insert 3. Furthermore, both the tubular insert 3 and the heater 2 placed thereon are enclosed, at the same side of the steam generator as the entrance 9 into said guide 7 is formed, by means of said barrier 8 having approximately semicircular cross-section. Said barrier extends vertically from the neighbourhood of the mouth of the free end of said insert 3 and up to the area above said bottom 1' so as the water conveyed via said inlet extension 4 is enabled free entrance to the area of the heater 2 where said water evaporates. It is provided for, according to the present invention, that when installed said guide 7 is formed in a manner to resemble together with the generator body 1, in three consecutive sections 10, 11, 12 an approximate shape of the Venturi tube. The first section 10 being formed between the guide 7 and the first vertical generator wall, the second section 11 being formed between the guide 7 and the top generator wall, and the third section 12 being formed between the guide 7 and the second vertical generator wall.

The water flowing via said inlet extension 4 into the generator body 1 (arrow A) runs around the outer side of said heater 2 and said tubular insert 3 behind the barrier 8 (arrow D). On contact of the water with said heater 2 the water is evaporating and a wet steam is developing which flows in the direction from the bottom 1' towards the generator top. The wet steam is afterwards conveyed through the consecutive sections 10, 11, 12 (arrow E) where the velocity of the wet steam changes due to the changing cross-sections of the path. Due to the centrifugal force and higher specific weight the fluid separates from the steam and flows over the generator wall. The fluid flows past by said entrance 9 (arrow F) which is intended to draw-off the steam, whereas the steam enters said guide 7 via said entrance 9 (arrow G). In the area of said entrance 9 there is a strongly enlarged cross-section of the steam path, again causing the steam velocity to drop so that in this section the remaining smallest water droplets are deposited. Afterwards, the steam is conveyed into said insert 3 (arrow B) where said steam is additionally heated and it receives as much energy as possible from the heater 2, thus, creating a dry steam being conveyed from said insert 3 via said outlet extension 5 (arrow C). By means of the steam generator according to the invention, the share of the dry steam increases substantially and, as a result, also the amount of energy which is received during the condensation of the steam by the food to be treated. Furthermore, a measure is provided according to the invention for treating the wet steam providing an installation of a pipe-like labyrinth 13 into said tubular insert 3. In the present embodiment, said pipe-like labyrinth 13 is formed of a plurality of mutually concentric pipes. Said labyrinth 13 is created in a manner that the outlet extension 5 for discharging the dry steam is extended from the area of said bottom 1' to the area below said mouth of the free end of the tubular insert 3. Concentrically with said extension 5, an additional pipe 14 being closed at the end facing away from said bottom 1' is arranged between said extension and the tubular insert 3, whereas said additional pipe being free at the opposite end and spaced from the bottom 1'. Said additional pipe 14 is spaced with the closed end thereof from said extension 5, so that a free passage for the steam is enabled from said tubular insert 3, between the additional pipe 14 and the outlet extension 5 (arrows H). Thus, the path of the steam being heated extends so that it reaches higher temperature and as high dryness as possible. In addition, due to increased efficiency of the steam heating the amount of the energy delivered to the heater 2 is lowered, since it has to be switched on fewer times, and simultaneously the dry steam carries higher energy for the food to be treated.

It is, however, possible for a man skilled in the art to use the invention in another way without departing from the spirit and scope of the invention. So it is possible, for instance, that said heater 2 is formed as a rod, a plate or similar. Furthermore, it is possible that said heater 2 can be tightly connected with said insert 3 by means of a shrink fit, by means of welding, adhesive bonding, metal casting and similar, so as to enable the highest possible heat transfer from the heater 2 to the insert 3. Still further it is possible that said inlet extension 4 and said outlet extension 5 are not connected to said generator body 1 at said bottom 1' since other embodiments are possible such as a side connection. Still further it is possible that said pipe-like labyrinth 13 at least partially contacts the surface of the tubular insert 3, thus, obtaining additional heating of the steam.

Claims

1. Cooking apparatus, particularly a household cooking apparatus, preferably a steam oven, and even more preferably a steam generator generating the steam for preparing food in said steam oven, characterized in that a tubular insert (3) being tightly associated with a heater (2) is arranged in a steam generator body (1), said tubular insert (3) being attached with the first end thereof to a bottom (Γ) of said body (1), whereas the opposite end of said tubular insert (3) remains free, wherein an inlet extension (4) is attached to the outside of said body (1), said extension being arranged outside the connection area of said tubular insert (3) with the bottom (Γ), and an outlet extension (5) is attached to the outside of said body (1) extending to the inside of said tubular insert (3).

2. Cooking apparatus according to claim 1, characterized in that a water trap (6) is attached to the free end of said tubular insert (3).

3. Cooking apparatus according to claim 1, characterized in that a labyrinth (13) is incorporated into said tubular insert (3).

4. Cooking apparatus according to any of the preceding claims, characterized in that said water trap (6) is formed of a dome-like guide (7) with an entrance (9) for entering the steam, and of a barrier (8) enclosing said tubular insert (3) as well as the heater (2) placed thereon.

5. Cooking apparatus according to any of the preceding claims, characterized in that said guide (7) is formed in a manner that it resembles with said body (1) in three consecutive sections (10, 11, 12) an approximate shape of the Venturi tube, the first section (10) being formed between the guide (7) and the first vertical generator wall, the second section (11) being formed between the guide (7) and the top generator wall, and the third section (12) being formed between the guide (7) and the second vertical generator wall.

6. Cooking apparatus according to any of the preceding claims, characterized in that said pipe-like labyrinth (13) is formed of a plurality of mutually concentric pipes (5, 14).

7. Cooking apparatus according to any of the preceding claims, characterized in that said heater (2) is enclosed from the outside thereof with a liner (2').

8. Cooking apparatus according to claim 6, characterized in that a said labyrinth (13) is formed of the outlet extension (5) extending from the area of said bottom (Γ) to the area below said mouth of the free end of the tubular insert (3), and of an additional pipe (14) arranged concentrically with said extension (5) between the latter and the tubular insert (3).

9. Cooking apparatus according to claims 6 and 7, characterized in that said additional pipe (14) is closed at the end facing away from said bottom (Γ), whereas it is free at the opposite end and spaced from the bottom (Γ) and said extension (5).