RS62045B1 - Device for cooling products - Google Patents

Description

Description

[0001] The invention relates to a device for cooling products, with a cyclone that has a housing with a circular cylindrical rear part and an adjacent front part of a conical shape, wherein on the upper front side of the rear part, which is opposite the front part, a cover is placed with a drain for the exit of gases that is concentrically carried out through it, and is provided in the interior of the cyclone separately from the cover with a circular opening for the discharge of gases, with an inlet nozzle connected to the supply water of the cryogenic agent for cooling, which flows tangentially into the rear part in the area of the upper face, and at least one feed water for the product to be cooled, which flows into the rear part.

[0002] Liquid, creamy or powdered products, especially foodstuffs, such as fillings for cakes, sauces and marinades, which are produced at high temperature, often have to be cooled quickly after production, for example, to preserve the internal structure of the product or to suppress the growth of bacteria. Cooling, for example, can be done using electric conventional cooling devices, but this is associated with high energy consumption. An alternative is direct contact of the product being cooled with a cryogenic refrigerant. The refrigerant absorbs part of the heat of the product and then evaporates or sublimates without the rest.

[0003] By "cryogenic refrigerant" in the following, we mean such liquid, solid or gaseous media which, when in contact with the product being cooled, have a temperature of -20°C and lower. In particular, the cryogenic refrigerant is a liquefied gas, such as, for example, liquid nitrogen, or carbon dioxide in solid or liquid form.

[0004] When using carbon dioxide as a cryogenic refrigerant, it is usually introduced in liquid form under a pressure greater than 5.18 bar, and on one nozzle, the so-called expansion nozzle, it is released to atmospheric pressure (1 bar). In doing so, carbon dioxide is cooled to a temperature of minus 78.9°C (194 K), whereby a mixture of dry ice and cold gaseous carbon dioxide is formed. Then at least the carbon dioxide particles are used to cool the product, and, for example, are applied to the surface of the product to be cooled, or, in the case of a liquid, cream or powder product, are mixed with the product.

[0005] From the patent EP 1734320 A2 a device is known, in which the product to be cooled, which can be pumped, and a cryogenic refrigerant, such as, for example, liquid nitrogen, liquid carbon dioxide, liquid argon or liquid air, are brought into contact in a vortex screw cooler and thoroughly mixed. The mixture is then led to a separator, where the vaporized cryogenic refrigerant is extracted. The cooled product is then ready for further processing or packaging.

[0006] From WO 2005/053440 A1, a device for cooling liquid products is known, whereby a cryogenic refrigerant, for example, liquid nitrogen or liquid carbon dioxide, is introduced into the container filled with the product to be cooled. The coolant evaporates on thermal contact with the product and is extracted from the upper part of the container. After the cooling process, the cooled product is drained through the water that is connected at the bottom of the container.

[0007] Patent WO 2016/060869 A1 relates to a device for cooling liquid foods, for example, sauces. In this subject matter, the product is carried through a pipeline in which there are one or more places where a cryogenic refrigerant, for example, liquid nitrogen, is introduced. However, the construction of the described device is very complex, especially because the refrigerant, which expands rapidly during evaporation, requires a pressure-stable pipeline construction.

[0008] EP 3234 485 A1 describes a process in which the cooled product is brought into contact with expanded carbon dioxide in a cyclone. A mixture of solid particles of carbon dioxide and products is obtained, which is discharged through the exit hole placed at the bottom of the cyclone. Only a short contact between the product and the carbon dioxide particles leads to only a relatively weak cooling of the product.

[0009] Patent DE 102014 018981 A1 also refers to a process for the production of subcooled dry ice, whereby liquid carbon dioxide is introduced into the expansion chamber through an expansion nozzle, where it expands with the formation of a mixture of gaseous carbon dioxide and dry ice, and finally the mixture is separated into a phase that mainly contains dry ice, as well as a phase that mainly contains gaseous carbon dioxide.

[0010] Therefore, the invention aims to indicate an efficient possibility, easy to handle, for cooling liquid, especially liquid or powder products.

[0011] This task is solved by means of a device with the characteristics of claim 1, and a method with the application of the device according to the invention with the characteristics of claim 5.

[0012] Suitable embodiments are provided in the subclaims.

[0013] According to the invention, the device of the mentioned type and purpose is also characterized by the fact that the outlet opening of the front part is fluidly connected to the product drain for the cooled product, in which there is a means for creating a counter-pressure that opposes the pressure of the product flow coming out of the product drain.

[0014] The device according to the invention thus includes a cyclone, the housing of which, in a known manner, has a cylindrical rear part and an adjacent conical front part, which flows into the outlet opening. On the upper front side of the rear part, which is located opposite the front part, there is a cover with a drain for the exit of gases, which is concentrically made through it and extends inside the cyclone separately from the cover with a circular opening for the discharge of gases (also called an immersion tube). The cyclone usually stands upright, with the outlet of the front part placed downwards and the outlet of the gas discharge upwards. In the rear part of the cyclone, the supply line for the coolant is tangentially fed, which is provided with a nozzle opening on the front side.

Furthermore, the supply line for the supply of the cooled product is poured into the rear part. For example, the product feed line is poured substantially at a right angle or sharp angle to the direction of the refrigerant flow, in the rear, separate from the nozzle opening of the refrigerant feed line. In order to avoid freezing of products on the cyclone walls, they can be supplied with heaters, for example, electric ones.

[0015] During the use of the device, due to the introduction of the coolant and its expansion and/or evaporation, a significant flow pressure is exerted in the direction of the outlet opening of the front part. Surprisingly, it has been shown that particularly effective cooling of the product can be achieved when a certain back pressure is created against this flow pressure. The reason for the increased cooling efficiency is not fully clarified, perhaps the counter pressure leads to a longer stay of the product in the cyclone, and thus to a longer contact time with the cryogenic refrigerant. The invention therefore ensures that the means for creating such a back pressure are arranged on the water for the removal of the product next to the exit opening.

[0016] Means for creating counter pressure include means for creating resistance to the flow in the water for removing the product, such as, for example, a diaphragm or other reduction of the cross-section of the flow. In one embodiment, they include a throttle valve, by which a specific target back pressure can be set. This embodiment is particularly recommended when different products are to be cooled in the device, and a certain cooling effect is required, independent of the type and properties of the product, such as, for example, temperature or viscosity and/or the temperature to be adjusted. The throttle valve can also be made to be adjustable, and during the cooling process the back pressure is adjusted depending on the measured parameter, such as, for example, the outlet temperature of the product.

[0017] In another embodiment, the means for creating counter pressure comprise a section of water for draining the product, which is constructed as a siphon, and comprises at least one section of water that goes geodesically upwards. When the device is working, a column of cooled product is formed in the water section that goes vertically upwards, whose weight (for liquid products: hydrostatic pressure) acts as a counter pressure against the flow pressure at the outlet of the cyclone. Of course, the means for creating back pressure can also be combined, for example, a diaphragm or a throttle valve in the water supply line with a section of water that goes vertically upwards.

[0018] A particularly suitable embodiment of the invention foresees that the supply line of the product being cooled flows into the rear part, so that the current of the product that flows out of it is directed to the current of the coolant supplied to the supply nozzle. As a result, already after introducing the product, a thorough mixing of the product and the coolant is achieved.

[0019] The product is preferably supplied via a supply line that is vertically poured into the flow of the coolant, which, for example, is supplied through the cover of the rear part, and at least its end part runs parallel to the longitudinal axis of the cyclone. In this case, the product is fed into the cyclone substantially perpendicular to the flow direction of the refrigerant. The product feed line can also be acutely angled into the rear, with one component each to direct parallel and vertical to the refrigerant flow. In addition, the product feed line can be equipped with a spray nozzle on the pour side.

[0020] In one particularly suitable embodiment of the invention, the supply line for the product does not flow directly under the supply nozzle for the coolant in the rear part, but is axially separated from it. Preferably, the product feed line is fed into the rear 1 cm to 10 cm in front of the feed nozzle, particularly preferably 2 cm to 5 cm. In this embodiment, the product stream encounters and is carried by the already expanded coolant stream.

[0021] The aim of the present invention is also achieved by a process for cooling the product, using a device according to the invention, with characteristics according to claim 5. In this case, the cryogenic coolant is introduced tangentially into the cyclone at the inlet of the feed nozzle in the rear part of the cyclone. At the same time, the product to be cooled is introduced into the product flow directed towards the flow of the introduced refrigerant. The mixture of coolant and product is separated in the cyclone, with the product being removed via the product drain line, which exits from the conically shaped front part in continuation of the rear part. The vaporized refrigerant is removed via the exhaust outlet in the rear part of the cyclone.

[0022] According to the invention, a counter pressure, which acts against the pressure of the product flow that is coming out, is created in the water for draining the product from the downstream side. The back pressure is adjusted to a predetermined value by means of a suitable means, or it is adjusted depending on some measured value. As a means can be used, for example, a throttle valve or a constriction in the water for draining the product, or maintaining a column of liquid in relation to which hydrostatic pressure is to be carried out to discharge the product being cooled. By applying counter pressure, the flow conditions in the cyclone are changed in such a way that there is a longer contact time between the product and the coolant, thus resulting in a more efficient cooling of the product.

[0023] The counter pressure is set to a value of 0.03 to 0.2 bar, particularly preferably to a value of 0.05 to 0.1 bar. Liquid nitrogen or liquid carbon dioxide is preferably used as a cryogenic coolant, which expands upon entering the cyclone, giving a mixture of gaseous and solid carbon dioxide.

[0024] The method according to the invention and the device according to the invention are suitable for cooling a liquid, fluidized or powdered product. The device according to the invention is especially used for cooling fat- or water-based foodstuffs, especially liquid foodstuffs, such as, for example, sauces, soups or juices, with or without solid ingredients. After cooling in the device according to the invention, the product can then be subjected to additional processing procedures, or taken to packaging. Gaseous refrigerant produced during the cooling process, for example carbon dioxide gas, is removed via the gas outlet, and can, for example, also be used to pre-cool the refrigerant supplied to the cyclone.

Example:

[0025]

The rear part of the cyclone of the device according to the invention has a pipe diameter, for example, from 250 mm to 300 mm. A water product with a mass flow rate of 2.5 m<3>/h is fed into the rear part.

At the same time, liquid carbon dioxide is supplied as a cooling agent, with a mass flow rate of 1.2 t/h. A back pressure of 0.05 bar to 0.1 bar is created in the product drain water, for example by means of a throttle valve. The product that is drained at the outlet of the product drain has a temperature that is up to 40°C lower than the temperature of the supplied product.

[0026] One example of embodiment will be described in more detail according to the drawing. The schematic representation represents the following:

Sl. 1: The device according to the invention in a section along the line I-I in Fig. 2,

Sl. 2: Device from Fig. 1 on the section along line II-II in Fig. 1,

[0027] The device 1 for cooling the product shown in the drawings includes a cyclone 2, whose housing in a known manner has a rear part 3 with a circular cylindrical cross-section of radius Rz, and an adjacent front part of a conical shape 4, which flows into the outlet opening 5 of radius Rp. Cyclone 2 is made of a material that conducts heat poorly, such as stainless steel or titanium, and may also have a coating as thermal insulation, which is not shown here.

[0028] On its front side, which is located opposite the front part 4, the rear part 3 is closed by a cover 6. The cylindrical exhaust pipe for gases 7 of the inner radius RG, which is connected to the gas outlet in a manner not shown here, passes through the middle of the cover 6, whereby between the outer wall of the exhaust pipe for gases 7 and the inner wall of the rear part 3 there is a circular ring 8 of width BR. The exhaust gas pipe 7 enters deep into the interior of the cyclone 2 and ends with the gas outlet opening 11 approximately at the height of the plane 12 of the transition between the rear part 3 and the front part 4 of the cyclone 2. The rear part 3, the front part 4 and the exhaust gas pipe 7 are arranged along a common vertical axis 9, with the outlet opening 5 located at the bottom and the exhaust gas pipe 7 at the top in the cyclone 2. For example, the radius Rz is from 10 cm to 15 cm, the radius RGod 5 cm to 10 cm, and the radius RPod 5 cm to 10 cm.

[0029] Into the rear part 3 of the cyclone 2, the feed nozzle 14 for the cryogenic coolant is poured, which is flow-connected via the feed line 15 to the source of the cryogenic coolant, which is not shown here. The source, for example, can be a reservoir for liquid cryogenic nitrogen or for pressurized liquefied carbon dioxide. The end part of the feed line 15, on the front side of which there is a feed nozzle 14, is placed in the tangential supply part 16 of the cyclone 2, and axially in relation to it. The flange connection 17 provides a gas-tight connection between the supply line 15 and the supply part 16.

[0030] Furthermore, a line for supplying the product 18 is provided, which on the rear part 3 flows into the outlet opening 19 on the cover 6, vertically or at an angle, with an additional tangential part for direction. The outlet opening 19 is positioned so that it is aligned with the end part of the feed line 15, and is poured at an axial distance D from the feed nozzle 14 which is, for example, from 2 cm to 5 cm.

[0031] The outlet opening 5 of the front part 4 continues with the product drain line 20, for draining the cooled product, which in the embodiment shown here continuously has a cross-sectional radius RP, which corresponds to the radius of the outlet opening 5 of the cyclone. The product drainage line 20 has a U-shaped water section, which, when using the device 1, is directed geodesically downwards by the bend 21, and by the arms 22, 23 upwards, whereby the arm 22 continues directly to the outlet opening 5. The bend 21 and the arms 22, 23 of the U-shaped water section are so dimensioned that it can maintain a liquid column of height H, for example, from 500 mm to 800 mm.

[0032] During the operation of the device 1, a cryogenic refrigerant, for example carbon dioxide liquefied under pressure, which is supplied via the supply line 15 under a pressure greater than 5.18 bar (abs.), for example a pressure of 18 to 20 bar (abs.), is supplied to the feed nozzle 14, and flows into the cyclone 2. On the feed nozzle 14, carbon dioxide expands with the creation of a stream of gaseous carbon dioxide and of dry ice, which flows tangentially into the circular ring 8 between the inner wall of the rear part 3 and the outer wall of the exhaust pipe for gases 7, and is directed there to the spiral path 25 which descends in the direction of the front part, as indicated in Fig.2. Instead of carbon dioxide, another cryogenic refrigerant can be used, for example liquid nitrogen.

[0033] At the same time as the cooling agent, the liquid product to be cooled is supplied through the product supply line 18. The product is thoroughly mixed in front of the opening 19 with the coolant supplied via the feed nozzle 14, and is carried along by it. At the same time, the coolant takes heat from the product and evaporates, that is, sublimes, at least partially, whereby the product cools.

[0034] In a manner known per se, the spiral path 25 of the vaporized refrigerant is transformed at the height of the gas outlet opening 11 into a spiral path that descends inside the gas exhaust pipe 7. The gaseous refrigerant that exits the gas exhaust pipe 7 is then preferably collected and, for example, used for pre-cooling the supplied refrigerant in the feed line 15. Through the circular flow in the cyclone 2, Liquid droplets, i.e. product particles, after a few revolutions at the latest, are accelerated due to the centrifugal force on the inner wall of the conical front part 4, and are attached in such a way that they separate from the flow and go downwards in the direction of the exit opening 5. The liquid product is finally drained through the U-shaped water section, the product drainage water 20.

[0035] The introduction and expansion of the cooling agent in the cyclone 2 leads to a strong pressure of the product flow in the direction of the product discharge lines 20. When flowing over the product discharge lines 20, the product must overcome the leg 23 of the U-shaped water section, and thus the hydrostatic pressure corresponding to the hydrostatic pressure of the height H, which acts as a counter-pressure to the pressure of the product flow. For example, a back pressure of 0.05 bar to 0.08 bar leads to a longer average contact time between the liquid droplets of the product and the coolant, thus resulting in significantly better cooling of the product compared to direct downward discharge. In addition, the device according to invention 1 can be used for cooling powder products in the same way.

List of reference marks

[0036]

1. Device

2. Cyclone

3. The back part

4. Front part

5. Outlet

6. Lid

7. Exhaust pipe

8. Circular ring

9. Wasp

10. -11. Gas outlet

12. Flat

13. -14. Feed nozzle

15. Supply line

16. Inlet section

17. Flange connection

18. Product supply line

19. Outlet

20. Line for draining the product

21. Curve

22. Arm

23. Arm

24th -25th Path

Bz Annular gap width

RGInner radius of gas outlet

Rp Inner radius of the product drain line

Rz Internal radius of the rear part of the cyclone

H The height of the liquid column in the water for removing the product

D The distance between the feed nozzle and the product supply line

1

Claims (7)

Patent claims 1. A product cooling device, with a cyclone (2), which has a housing with a circular cylindrical rear part (3) and an adjacent conical front part (4) with an outlet opening (5), whereby a cover (6) is placed on the upper front side of the rear part (3) opposite the front part (4) with a gas outlet (7) concentrically through it, and extends inside the cyclone (2) separately from the cover (6) with a circular a gas outlet (11), with a supply nozzle (14) connected to a feed water (15) of cryogenic coolant, which flows tangentially into the rear part (3) in the area of the upper face, and at least one feed water (18) for the product to be cooled that flows into the rear part (3), indicated by, which is the outlet opening (5) of the front part (4) fluidly connected to the product outlet (20) for the cooled product, in which there is a means (21, 22, 23) for creating a counter pressure that opposes the pressure of the product flow coming out of the product outlet (20), wherein means (21, 22, 23) for creating counter pressure includes a throttle valve or a constriction and/or a section of water that goes geodesically upwards (23) of water for removing the product (20), in which a column of liquid whose hydrostatic pressure acts as a counter pressure can form during the operation of the device. 2. The device according to claim 1, characterized by the fact that the line (18) for supplying the product flows into the rear part (3), so that the flow of the product coming out of it is directed to the flow of the coolant supplied to the feed nozzle (14). 3. Device according to one of the previous claims, characterized in that the line (18) for supplying the product, axially distant from the feed nozzle (14) for the coolant, flows into the rear part (3) of the cyclone (2). 4. Device according to one of the previous claims, characterized in that the line (18) for supplying the product is essentially parallel to the longitudinal axis (9) of the cyclone (2) at least with its end part that flows into the cyclone (2). 5. A method for cooling the product using a device according to one of the previous requirements, in which the cryogenic coolant is fed tangentially to the rear part (3) of the cyclone housing (2) on the supply nozzle (14), through the feed line (18) which flows into the cyclone (2), the product to be cooled is fed into the flow of the supplied coolant and mixed with it, at the end the mixture of the coolant and the product is separated in the cyclone (2), while the product is drained through the water for removing the product (20) that comes out of the front part of the conical shape (4) in the extension of the back part (3), and the vaporized coolant through the outlet for the exit of gases (7) that flows into the back part (3), indicated by that in the water for removing the product (20) on the downstream side of the flow, a counter-pressure is created that acts against the flow pressure of the outgoing product, whereby the counter-pressure is set to a value of 0.03 to 0.2 bar, preferably from 0.05 to 0.1 bar. 6. The method according to claim 5, characterized in that liquid carbon dioxide or liquid nitrogen is used as a cryogenic refrigerant. 7. The method according to one of claims 5 or 6, characterized in that the product is a liquid or powder product.