Steam condenser with heat exchanger and a cooking oven with such steam condenser

Abstract

The object of the invention is a steam condenser for a cooking oven, especially for a combi steamer, having a housing, having side walls and having at least partly open front side and back side to facilitate flow of cooling air through the steam condenser, and a heat exchanger located in said housing, which serves as a condenser, wherein the heat exchanger comprises a number of connected finned tubes through which water vapor with other gases from the cooking oven, especially combi steamer, are guided, wherein the steam condenser comprises a condensate drainage system, wherein the finned tubes are arranged between the side walls of the housing, wherein the steam condenser is also provided with 180o connectors, characterized in that the finned tubes are arranged in two rows, ie. upper row and lower row, and all the finned tubes on their ends on one side of the condenser, either left or right, are provided with the 180o connectors, so that the finned tubes are connected in pairs with each pair consisting of one finned tube from the upper row and one finned tube from the lower row, the flow of the water vapor and other gases form the cooking oven is arranged such, that it first is introduced form the oven into an inlet space, where it splits and flows through finned tubes from the upper row, then passes through 180o connectors and then passes through finned tubes from the lower row, after which it reaches an exit space, wherein the inlet space and the exit space are separated from each other, wherein the cooling air flowing through the steam condenser is directed to first pass by the finned tubes from the lower row and afterwards to pass by the finned tubes from the upper row, thus enabling a counter-flow exchange of heat. Another object of the invention is a cooking oven, especially a combi steamer, provided with the steam condenser according to the present invention. (Fig. 3) (12 claims)

Description

[0001] Steam condenser with heat exchanger and a cooking oven with such steam condenser

[0002] The present invention relates to a steam condenser equipped with a heat exchanger acting as a water vapor condenser, for use in gastronomic ovens, especially combi steamers, as well as to a cooking oven equipped with such steam condenser.

[0003] While in the solution known from EP4172544B1 the steam condenser has a single zig-zag of tubes that allows for cooling the exhaust gases from cooking ovens - it produces a relatively long conduit for the gases to pass through. It has been found desirable to improve such device to make it more compact so that it takes up less space, while maintaining good cooling / condensing capabilities, and simultaneously increasing the flow of the water vapor and gases that can be cooled by it.

[0004] The aim of the invention is to provide an improved steam condenser, which would be smaller in size while at the same time - allowing to receive a bigger flow of gasses to be cooled and condensed. Another aim of the invention is to provide a cooking oven with such improved steam condenser.

[0005] The object of the invention is a steam condenser for a cooking oven, especially for a combi steamer, having a housing, having side walls and having at least partly open front side and back side to facilitate flow of cooling air through the steam condenser, and a heat exchanger located in said housing, which serves as a condenser, wherein the heat exchanger comprises a number of connected finned tubes through which water vapor with other gases from the cooking oven, especially combi steamer, are guided, wherein the steam condenser comprises a condensate drainage system, wherein the finned tubes are arranged between the side walls of the housing, wherein the steam condenser is also provided with 180° connectors, characterized in that the finned tubes are arranged in two rows, i.e. upper row and lower row, and all the finned tubes on their ends on one side of the condenser, either left or right, are provided with the 180° connectors, so that the finned tubes are connected in pairs with each pair consisting of one finned tube from the upper row and one finned tube from the lower row, the flow of the water vapor and other gases form the cooking oven is arranged such, that it first is introduced form the oven into an inlet space, where it splits and flows through finned tubes from the upper row, then passes through 180° connectors and then passes through finned tubes from the lower row, after which it reaches an exit space, wherein the inlet space and the exit space are separated from each other, wherein the cooling air flowing through the steam condenser is directed to first pass by the finned tubes from the lower row and afterwards to pass by the finned tubes from the upper row, thus enabling a counter-flow exchange of heat. Preferably, the exit space is further connected to a number of outlet tubes with orifices, that are arranged after the upper row of the finned tubes, when looking along the direction of the flow of the cooling air, wherein the orifices are arranged on the top-part of the outlet tubes.

[0006] Preferably, the outlet tubes have airfoil shape in cross section.

[0007] Alternatively, the exit space is further connected to an outlet port, to guide the gasses towards the front side of the steam condenser, so that they can mix with the flow of the cooling air before this flow of the cooling air enters the steam condenser.

[0008] Preferably, the finned tubes from the upper row and the lower row are all arranged as inclined down towards the same side of the steam condenser, be it right or left side, so as to allow the condensate from within the finned tubes to flow back towards the inlet space and exit space, respectively.

[0009] Alternatively, the finned tubes from the upper row are arranged as inclined down starting from the inlet space, and the finned tubes from the lower row are arranged as inclined down towards the exit space, so as to allow the condensate from within the finned tubes to flow towards exit space.

[0010] Preferably, the drainage system further comprises an inlet space drainage port. Preferably, the drainage system further comprises an exit space drainage port. Preferably, the exit space at the bottom thereof is provided with a siphon arrangement, configured to gather condensate flowing out of the finned tubes of the lower row, and to allow the condensate above the predetermined level to drain from the siphon arrangement down towards the inlet space, wherein the inlet space is arranged to guide the condensate flowing out of the finned tubes of the upper row and out of the siphon arrangement to flow towards a connection to the cooking oven, wherein the inlet space and the outlet space are separated by a predetermined level of water present in the siphon arrangement, which prevents the flow of water vapor and other gasses directly from inlet space to exit space.

[0011] Preferably, the number of the finned tubes is divisible by two and is between two and forty-eight finned tubes, preferably the number of finned tubes is four, six, eight, ten, twelve, fourteen, sixteen, eighteen, twenty, twenty-two, twenty-four, twenty- six, twenty eight, thirty, thirty-two, thirty-four, thirty-six, thirty-eight, forty, forty-two, forty- four or forty-six.

[0012] Preferably, the number of the outlet tubes is between one and ten, and is preferably two, three, four, five, six, seven, eight or nine.

[0013] Another object of the invention is a cooking oven, especially a combi steamer, provided with the steam condenser according to the present invention.

[0014] The present invention will be presenter in greater detail in correspondence to accompanying drawings, where:

[0015] Fig. 1 presents a perspective view of an embodiment of the condenser as seen from the back,

[0016] Fig. 2 presents a cross-section of the condenser from Fig. 1 , Fig. 3 presents a cross-section of the condenser from Fig. 1 , along one pair of the finned tubes,

[0017] Fig. 4 presents a cross-section of an embodiment of the condenser, across the finned tubes,

[0018] Fig. 5 presents a cross-section of an embodiment of the condenser, with visible inlet and exit spaces and a siphon arrangement,

[0019] Fig. 6 presents a cross-section of an embodiment of the condenser, that is an alternative to the condenser of Figs. 1 -5, with additional outflow tubes and a drainage port in the exit space,

[0020] Fig. 7 presents a cross-section of the condenser from Fig. 6 in a perspective view from the front, with some of the outflow tubes removed,

[0021] Fig. 8 presents a cross-section of the condenser from Fig. 7, in a perspective view from the back,

[0022] Fig. 9 presents a cross-section of the condenser according to another embodiment, showing a alternative way of guiding water vapor and other gasses to the condenser,

[0023] Fig. 10 presents a cross-section of the condenser according to another embodiment, showing an alternative way of guiding gasses out from the exit space,

[0024] Fig. 11 presents a cross-section of the embodiment of the condenser, provided with an airfoil-shaped outflow tube,

[0025] Fig. 12 presents a cross section of the condenser with two airfoil-shaped outflow tubes,

[0026] Fig. 13 presents a close-up of a detail from Fig. 12,

[0027] Fig. 14 presents an exemplary airfoil shaped outflow tube in a perspective view, Fig. 15 presents a variant of the steam condenser, with visible exemplary inlet space drainage port.

[0028] Numeric references:

[0029] 1 - steam condenser

[0030] 2 - hood of the combi steamer with steam condenser

[0031] 3 - housing of the steam condenser

[0032] 4 - side walls of the housing

[0033] 5 - front side of the housing

[0034] 6 - back side of the housing

[0035] 7 - finned tube

[0036] 8 - inlet space

[0037] 9 - exit space

[0038] 10 - 180° connector

[0039] 11 - outlet tube with orifices

[0040] 12 - orifices

[0041] 13 - outlet port

[0042] 14 - inlet space drainage port

[0043] 15 - outlet space drainage port

[0044] 16 - siphon arrangement

[0045] 17 - connection to the cooking oven Preferable embodiments of the invention

[0046] The present invention provides a very particular type of a steam condenser 1 , that can be used to cool the exhaust gases coming from a cooking oven, e.g. from a combi steamer. Such gases can have a very high temperature and contain relatively high amounts of water vapor, so that they should be treater after leaving the cooking space, before being released to the atmosphere e.g. within or outside of the restaurant or a kitchen.

[0047] The steam condenser 1 has a housing 3 with side walls 4 and at least partly open front side 5 and a back side 6, that can also be preferably at least partly open. Within said housing 3 and between the side walls 4 there is provided a heat exchanger that acts as a condenser, and that is provided with a number of finned tubes 7, through which water vapor and other gasses are guided and in there they are cooled, thanks to the cooling air flowing on the outside of the finned tubes 7. The steam condenser 1 is also provided with a condensate drainage system, which takes away the condensate. Some of the neighboring ends of the finned tubes 7 are also connected to one another with the use of 180° connectors 10, similar to those known from EP4172544B1.

[0048] Basic arrangement of the steam condenser 1 is presented on Fig. 1 , with visible two rows of the finned tubes 7 and 180° connectors present on one of the sides of the stem condenser 1 .

[0049] Within the housing 3 of the steam condenser 1 there is provided a place where the outlet of the water vapor and other gases from the oven can be connected to - and these gases at first flow into the inlet space 8 (compare with Fig. 5, 6, 7 and 9). Such inlet space 8 provides a transfer zone from which the gases that will be subjected to cooling are directed to flow and enter into the finned tubes 7, that form an upper row. These finned tubes 7 that form the upper row are connected in parallel, so the flow of the gases that can be received by them is increased when compared to condenser that provide only a single tube for the gases to flow through, and also - the energy losses are decreased, since it takes less effort to ensure that the gasses flow through such number of parallel tubes.

[0050] At their ends - the finned tubes 7 from the upper row are provided with 180° connectors 10 that connect them to their respective paired finned tube 7 from the lower row (see Fig. 3). Thus, the steam condenser 1 is provided with a number of parallel cooling channels, constituted by the pairs of finned tubes 7. It has been found, that by using a number of pairs of finned tubes 7 increases the surface area where heat exchange takes place to such a degree, that the temperature of the gases passing through there can drop to a desired level and the majority of water vapor can turn into liquid. This allows to produce steam condensers with a relatively small size and good performance.

[0051] Also - the steam condenser 1 is arranged such, that while the water vapor and hot gases first flow through the finned tubes 7 of the upper row, and then from those of the lower row, the cooling air is guided to first flow around the finned tubes 7 from the lower row, and only afterwards - around the finned tubes 7 from the upper row. This on one side ensures a counter-flow heat exchange, which is a very desirable and efficient way of exchanging heat, while also helps in that the cooling air, which gets a bit hotter after passing by the finned tubes 7 from the lower row, becomes less dense I lighter and naturally begins to flow upwards - which on the other hand reduces the energy consumed by electrical fans that force the flow of the cooling air through the steam condenser 1 (compare with Fig. 11 , with visible fans mounted in an exemplary hood 2 provided with the steam condenser 1 ).

[0052] Ends of the finned tubes 7 from the lower row all open up into an exit space 9 (compare with Fig. 5, 6 and 7), and from this exit space 9 the now-cooled gases from the oven can be guided away from the steam condenser 1 , in a number of ways.

[0053] First preferable way of guiding the gasses out of the exit space 9 of the steam condenser 1 is to connect to it an outlet tube 11 with orifices 12. Such outlet tube 11 can be mounted generally above the finned tubes 7 of the upper row and after them, when looking in the direction of the flow of the cooling air (compare with Fig. 6 and 7).

[0054] The outlet tube 11 is provided with orifices 12 arranged on its top part, when in the mounted position - this allows for the flow of the cooling air to not be forced inside the outlet tube 11 (which would be highly undesirable and could cause malfunctions), but rather helps in sucking out the gases from the outlet tubes 11 and carrying them away, along with the flow of the cooling air.

[0055] With respect to the number of the finned tubes 7 and the outlet tubes 11 - it depends on the designed and desired performance of the particular steam condenser. Steam condensers 1 connected to ovens consuming more power / being simply bigger in size (meaning - ovens generating more water vapor and potentially more of other gases with it) - would usually require more pairs of finned tubes 7 and more outlet tubes 11 , to ensure the exhaust gases get sufficiently cooled and enough of water vapor gets condensed. On the other hand - smaller ovens could require noticeably smaller steam condensers 1 .

[0056] That is why, preferably - the steam condenser 1 is provided with between two and forty-eight finned tubes (7) arranged in pairs.

[0057] Also, preferably - when the outlet tubes 11 are utilized - their number is between one and ten.

[0058] In some embodiments, the outlet tubes 11 have a modified shape, having an airfoil-like cross section (see Fig. 11 , 12, 13 and 14). Such shape helps in some cases to increase the local velocity of the cooling air passing by the orifices 12, which can increase performance of the steam condenser 1 . Alternative arrangements of how to guide the gases out of the exit space 9, is to provide an outlet port 13 connected to the front of the steam condenser 1 , so that the flow of the cooling air being sucked into the steam condenser, e.g. by a number of fans (compare with Fig. 10) would provide enough difference in pressure and thus would suck the gases out of the exit space 9. Such version simplifies the structure of the steam condenser 1 , especially in the aspect of how the inlet space 8 and exit space 9 are formed and by eliminating the need to mount outlet tubes 11 (compare Fig. 10 and 11 ).

[0059] With respect to the finned tubes 7 themselves - in order for them to facilitate a stable and reliable flow of the condensate from them , they can be arranged in basically two ways:

[0060] 1 - all finned tubes 7 are mounted with an inclination towards one and the same side of the housing 3, so that the condensate from the upper row flows down towards the inlet space 8 and the condensate from the lower row flows down towards the exit space 9,

[0061] 2 - the finned tubes 7 from the upper row are inclined downwards from the inlet space 8, and the finned tubes 7 from the lower row are inclined downwards towards the exit space9, so that all of the condensate will flow through the finned tubes 7 towards the exit space 9.

[0062] These two options allow for a variety of ways to manage the condensate, since it can be decided by the final user where do they want to have the drainage ports located.

[0063] In some embodiments, it would be desirable to provide only one drainage port 15, that would be located on the bottom of the exit space 9.

[0064] In other embodiments, one could decide to provide two drainage ports 14, 15, one located in the inlet space 8, and the other located in the exit space 9, at the bottom of those, respectively.

[0065] There are also other preferable embodiments, where the exit space 9 is separated from the inlet space 8 with the use of a siphon arrangement 16 (compare with Fig. 5 and 10) - so that, when the steam condenser 1 is operating, in the exit space 9 a small level of condensate would be maintained. This - would allow to effectively block the gases from entering directly from the inlet space 8 to the exit space 9 through the siphon arrangement 16. On the other hand - while the condensate would gather in the exit space 9, after reaching a predetermined level it would overflow the siphon arrangement 16 and would start to flow into the inlet space 8. Such embodiments would allow for using drainage port 14 only in the inlet space 8, which presents a preferable alternative to simplify the construction of the steam condenser.

[0066] Alternatively - the siphon arrangement 16 can be provided essentially near the bottom of the inlet space 8 and exit space 9 (compare with Fig. 6, 7) - so that the drainage port 15 would be associated mainly with the exit space 9, the condensate that would gather in the inlet space 8 could naturally flow through the siphon arrangement 16 and then - to the drainage port 15. As it can be seen on e.g. Fig. 2 and Fig. 7 - the housing 3 of the steam condenser 1 can be provided with some additional plates (e.g. plate that form the front of side of the housing 5 - see Fig. 7), that would help in guiding the flow of the cooling air so that it first passes by the finned tubes 7 of the lower row, and has to flow more or less evenly and by the finned tubes 7 of the upper row.

[0067] It can be also seen on Fig. 8 and 9, that the connection 17 to the cooking oven can be realized in different ways - this connection 17 can be in a form of essentially vertical pipe, opening into the inlet space 8 (as seen on e.g. Fig. 8 or 10), or it can be bent - so that the pipe is essentially horizontal then opening into the inlet space 8 ( see Fig. 9). Such variations help in designing steam condenser 1 and making sure that it can fit to a particular oven. It is especially important in cases, when it would be allowable or even desirable to make it possible for some of the condensate form the inlet space to flow back through the connection 17 towards the oven, or to make it virtually impossible (e.g. by making the connection 17 horizontal in the area where it enters the inlet space 8 - see e.g. Fig. 9, or by making the connection 17 elevated above the inlet space drainage port 14 - see e.g. Fig. 15).

[0068] The steam condenser according to the present invention allows to achieve good performance-to-size ratio with respect to desired levels of exchange of heat and condensing water vapor from the oven and cooling other gases, while making it easy to combine it with different oven types, especially combi steamers.

Claims

Claims1 . A steam condenser (1 ) for a cooking oven, especially for a combi steamer, having a housing (3), having side walls (4) and having at least partly open front side (5) and back side (6) to facilitate flow of cooling air through the steam condenser (1 ), and a heat exchanger located in said housing (3), which serves as a condenser, wherein the heat exchanger comprises a number of connected finned tubes (7) through which water vapor with other gases from the cooking oven, especially combi steamer, are guided, wherein the steam condenser (1 ) comprises a condensate drainage system, wherein the finned tubes (7) are arranged between the side walls (4) of the housing (3), wherein the steam condenser (1 ) is also provided with 180° connectors (10), characterized in that the finned tubes (7) are arranged in two rows, i.e. upper row and lower row, and all the finned tubes (7) on their ends on one side of the condenser (1 ), either left or right, are provided with the 180° connectors (10), so that the finned tubes (7) are connected in pairs with each pair consisting of one finned tube (7) from the upper row and one finned tube (7) from the lower row, the flow of the water vapor and other gases form the cooking oven is arranged such, that it first is introduced form the oven into an inlet space (8), where it splits and flows through finned tubes (7) from the upper row, then passes through 180° connectors (10) and then passes through finned tubes (7) from the lower row, after which it reaches an exit space (9), wherein the inlet space (8) and the exit space (9) are separated from each other, wherein the cooling air flowing through the steam condenser (1 ) is directed to first pass by the finned tubes (7) from the lower row and afterwards to pass by the finned tubes (7) from the upper row, thus enabling a counter-flow exchange of heat.

2. The steam condenser (1 ) according to claim 1 , wherein the exit space (9) is further connected to a number of outlet tubes (11 ) with orifices (12), that are arranged after the upper row of the finned tubes (7), when looking along the direction of the flow of the cooling air, wherein the orifices (12) are arranged on the top-part of the outlet tubes (11 ).

3. The steam condenser (1 ) according to claim 2, wherein the outlet tubes (11 ) have airfoil shape in cross section.

4. The steam condenser (1 ) according to claim 1 , wherein the exit space (9) is further connected to an outlet port (13), to guide the gasses towards the front side (5) of the steam condenser (1 ), so that they can mix with the flow of the cooling air before this flow of the cooling air enters the steam condenser (1 ).

5. The steam condenser (1 ) according to any of the proceeding claims from 1 to 4, wherein the finned tubes (7) from the upper row and the lower row are all arranged as inclined down towards the same side of the steam condenser (1 ), be it right or left side,so as to allow the condensate from within the finned tubes (7) to flow back towards the inlet space (8) and exit space (9), respectively.

6. The steam condenser (1 ) according to any of the proceeding claims from 1 to 4, wherein the finned tubes (7) from the upper row are arranged as inclined down starting from the inlet space (8), and the finned tubes (7) from the lower row are arranged as inclined down towards the exit space (9), so as to allow the condensate from within the finned tubes (7) to flow towards exit space (9).

7. The steam condenser (1 ) according to claim 5, wherein the drainage system further comprises an inlet space drainage port (14).

8. The steam condenser (1 ) according to any of the proceeding claims from 1 to 7, wherein the drainage system further comprises an exit space drainage port (15).

9. The steam condenser (1 ) according to claim 4, wherein the exit space (9) at the bottom thereof is provided with a siphon arrangement (16), configured to gather condensate flowing out of the finned tubes (7) of the lower row, and to allow the condensate above the predetermined level to drain from the siphon arrangement (16) down towards the inlet space (8), wherein the inlet space (8) is arranged to guide the condensate flowing out of the finned tubes (7) of the upper row and out of the siphon arrangement (16) to flow towards a connection (17) to the cooking oven, wherein the inlet space (8) and the outlet space (9) are separated by a predetermined level of water present in the siphon arrangement (16), which prevents the flow of water vapor and other gasses directly from inlet space (8) to exit space (9).

10. The steam condenser (1 ) according to any of the proceeding claims from 1 to 9, wherein the number of the finned tubes (7) is divisible by two and is between two and forty-eight finned tubes (7), preferably the number of finned tubes is four, six, eight, ten, twelve, fourteen, sixteen, eighteen, twenty, twenty-two, twenty-four, twenty-six, twenty eight, thirty, thirty-two, thirty-four, thirty-six, thirty-eight, forty, forty-two, forty- four or forty-six.11 . The steam condenser (1 ) according to any of the proceeding claims from 1 to 10, wherein the number of the outlet tubes (11 ) is between one and ten, and is preferably two, three, four, five, six, seven, eight or nine.

12. A cooking oven, especially a combi steamer, provided with the steam condenser (1 ) as defined in any of the proceeding claims.

Images