Sanitary Steam Compressor

Abstract

A sanitary vapor compressor for use in injection plants for ultra-high throughput processing of fluid foods is provided that is more cost effective and more environmentally friendly than the prior art due to improved internal heat recovery. A sanitary compression device includes an impeller housing, an impeller, and a motor. The impeller housing has an axial inlet and a radial outlet. The axial inlet receives flash steam from a flash steam outlet of a flash vessel. The radial outlet supplies compressed flash steam to a thermal treatment device. The impeller is disposed in the impeller housing. The motor is configured to rotate the impeller. Flash steam enters the inlet and is radially accelerated and compressed in response to rotation of the impeller.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 433,881 (filed December 20, 2023), which is incorporated by reference in its entirety.

[0002] The present disclosure relates to a steam compressor for use in a plant for the ultra-high temperature processing of fluid foods such as milk or milk-based products, baby food, plant-based beverages, or nutritional beverages, the plant including a direct heat treatment unit in which the fluid is thermally treated by a supply of steam. [Background technology]

[0003] In UHT plants (ultra-high temperature plants), steam is sprayed into the fluid food in an injection chamber, for example, in such a way that the fluid food is heated to a temperature of about 140°C. The fluid food is then fed into a so-called holding chamber, where the fluid food is kept in the heated state for a predetermined period of time (about 2 to 15 seconds). The fluid food is then transferred to a flash vessel, where the water derived from the steam is removed in such a way that the solids content of the fluid food leaving the flash vessel are the same as those fed into the injection chamber before being subjected to the heat treatment. After being processed in the flash vessel, the fluid food is usually transferred to a homogenizer and then subjected to cooling and packaging.

[0004] EP 0 794 706 discloses an injection plant for high-temperature processing of fluid food products such as whey protein concentrates and cheese milk. The plant has an injection chamber in which the fluid is subjected to heat treatment by steam pumped into the injection chamber. The food product is introduced into the upper part of the injection chamber as a bundle of separate, mainly downward-directed jets. The lower section of the injection chamber serves to collect the food product and has a cooled wall with a cooling jacket. The outlet opening of the injection chamber is located at the bottom of the injection chamber and is connected to the inlet of a positive displacement pump. The outlet of the positive displacement pump is connected to the inlet of a vacuum chamber that serves to remove water from the food product added during steam injection.

[0005] US 4,419,301 discloses a process for heating a fluid to a sterilization temperature. The fluid is heated by direct contact with steam while it is in the form of a very thin free-falling film or a continuous falling stream. After the sterilization process, the added steam is removed in a flash vessel and the generated steam is condensed into a condensate that is discarded.

[0006] AU 61233 discloses an injection plant for continuous sterilization of liquids, in which unsterilized liquids, preferably after preheating, are sprayed into a sterilization chamber into which steam is fed, and the liquid heated by the steam is kept for a predetermined period of time, characterized in that the sterilization chamber (see injection chamber

[15] in Figure 1) includes at least one row of downward-facing outlet openings for the liquid at the top, the openings being arranged along a circle. The plant has an injection chamber, in which the fluid is subjected to heat treatment by steam fed into the injection chamber. The outlet opening of the injection chamber is located at the bottom of the injection chamber, and the outlet opening is connected to the inlet of a holding device. The outlet of the holding device is connected to the inlet of a vacuum chamber [item 7 in Figure 1], which serves to remove water from the food added during steam injection.

[0007] WO 2022 / 122401 discloses a process for heating a fluid to a sterilization temperature. The fluid is heated by direct contact with steam from a steam injection device. After heating, the added steam is removed in a flash vessel cooling device, where the steam is condensed into condensate that is discarded. While this disclosure describes the use of steam injection instead of steam injection, it has the same cooling device, a flash cooler, in which excess steam is condensed and discarded.

[0008] Infusion plants use high temperatures for short periods of time to kill microorganisms. This technique is widely used in the dairy industry, where products can lose their nutritional value, flavor, and appearance due to microbial growth. These microorganisms thrive at certain temperatures, but if they are absent from the product, the product can be stored for months without the need for refrigeration. Steam injection achieves this goal while minimizing thermal degradation compared to other UHT processes. It helps protect essential ingredients such as vitamins and results in a fresh-tasting product with superior quality. It provides the necessary kill rates for commercial sterilization and can handle a wide range of product viscosities, covering milk, puddings, ice cream, baby food, condensed milk, processed cheese, plant-based beverages, sauces, and fluids from creams to lotions.

[0009] There is a continuing need to improve the design and performance of thermal processing plants, such as injection plants, to achieve increasingly cost- and energy-efficient, and more environmentally friendly processes than the prior art.

[0010] It would therefore be desirable to provide a sanitary vapor compressor for a thermal processing plant that does not have the undesirable qualities of conventional vapor compressors. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] EP 0 794 706 [Patent Document 2] US 4,419,301 [Patent Document 3] AU 61233 [Patent Document 4] WO 2022 / 122401 Summary of the Invention [Problem to be solved by the invention]

[0012] It is an object of the present invention to provide a sanitary vapor compressor for use in injection plants for ultra-high throughput processing of fluid foods that is more cost-effective and more environmentally friendly than the prior art due to improved internal heat recovery. [Means for solving the problem]

[0013] The object of the present invention is achieved in a first aspect by providing a compression device having an impeller housing, an impeller, and a motor. The impeller housing has an axial inlet and a radial outlet. The axial inlet receives flash steam from a flash steam outlet of a flash vessel. The radial outlet supplies compressed flash steam to a heat treatment device. The impeller is disposed in the impeller housing. The motor is configured to rotate the impeller. Flash steam enters the inlet and is radially accelerated and compressed in response to rotation of the impeller.

[0014] The object of the present invention is achieved according to a second aspect of the present invention by providing a plant for thermally treating a fluid food such as milk, a milk-based product, baby food, baby food liquid concentrate, or nutritional drink, the plant comprising a heat treatment device having a fluid food inlet arranged at an upper part of the heat treatment device, a fluid food outlet arranged at a lower part of the heat treatment device, and a first steam inlet arranged at the upper part of the heat treatment device, the fluid food being subjected to thermal treatment by feeding live steam and / or flash steam into the heat treatment device, the live steam being fed into the heat treatment device by a live steam conduit connected to the first steam inlet, a flash vessel having a fluid food inlet at a side of the vessel and a fluid food outlet at a bottom of the flash vessel, the plant comprising a fluid food outlet of the processing apparatus connected by a conduit and a pump to the fluid food inlet of the flash vessel, the fluid food outlet of the flash vessel connected to a conduit and a pump for discharging the fluid food from the flash vessel, the flash vessel further comprising a flash steam outlet arranged in an upper portion of the flash vessel, the flash steam outlet connected to a flash steam conduit, the flash steam conduit connected to an inlet of a compression arrangement (compression arrangement), the flash steam conduit adapted to deliver the flash steam to the compression arrangement, where the flash steam is compressed, and a second flash steam conduit connected to an outlet of the compression arrangement, the second flash steam conduit adapted to transport the flash steam to the heat treatment apparatus.

[0015] Embodiments of the present invention allow the low-pressure waste flash steam of a UHT plant to be reused instead of simply being vented to the atmosphere. Waste flash steam is approximately a 50% loss of UHT plant heating energy, so when 1000 kg of steam is added for injection UHT heating, a conventional direct UHT system loses 500 kg of steam through waste flash steam. Using a flash steam recovery system such as that of the present invention, all of this 50% flash steam waste heat can be recovered and reused. Embodiments of the present invention increase the reuse of steam for injection heating from 50% to 100%.

[0016] In a first possible embodiment of the first aspect, the second flash steam conduit is connected to the live steam conduit, allowing the heat treatment device to have only one steam inlet.

[0017] In a second possible embodiment of the first aspect, the second flash steam conduit is connected to a second steam inlet arranged at the top of the heat treatment device, providing a solution whereby the injection of live steam and flash steam can be adjusted independently of each other.

[0018] In a third possible embodiment of the first aspect, a thermal vapor recompression device is connected to the second flash vapor conduit and further compresses the flash vapor in response to demand.

[0019] In a fourth possible embodiment of the first aspect, the compression arrangement includes at least one compression device to facilitate mechanical compression of the flash vapor to a higher pressure so that it can be reused.

[0020] In a fifth possible embodiment of the first aspect, the compression arrangement comprises two compression devices connected in series, allowing the vapor pressure to be reduced in appropriately large steps.

[0021] In a sixth possible embodiment of the first aspect, the compression device comprises a vapor compressor.

[0022] In a seventh possible embodiment of the first aspect, the compression device comprises a heat pump.

[0023] In a ninth possible embodiment of the first aspect, the compression device includes a turbocharger, further reducing the amount of energy required to operate the plant.

[0024] In a tenth possible embodiment of the first aspect, live steam is generated by a steam boiler, which is a simple and reliable solution.

[0025] In an eleventh possible embodiment of the first aspect, the steam boiler is adapted to provide steam to the turbocharger, eliminating the need to separately power the turbocharger.

[0026] In a twelfth possible embodiment of the first aspect, the conduit and pump are adapted to transfer the fluid food product to the aseptic homogenizer.

[0027] In a thirteenth possible embodiment of the first aspect, the fluid food product is heat sensitive.

[0028] In a fourteenth possible embodiment of the first aspect, the plant does not include a condenser connected to the outlet of the flash vessel.

[0029] In a fifteenth possible embodiment of the first aspect, the thermal processing apparatus includes a steam injection chamber.

[0030] In a sixteenth possible embodiment of the first aspect, the thermal treatment apparatus comprises a steam injector device.

[0031] The object of the present invention is achieved in a second aspect by a method of operating an ultra-high temperature processing plant having a heat treatment device, in which a fluid food product is subjected to heat treatment with live and / or flash steam, the method comprising the steps of feeding the fluid food product into the heat treatment device, feeding live steam and / or flash steam into the heat treatment device, removing the fluid food product from the heat treatment device, feeding the fluid food product into a flash vessel, removing the fluid food product from the flash vessel, removing flash steam from the flash vessel, and feeding the flash steam to a compressor arrangement (compressor arrangement) that compresses the flash steam after it is fed into the heat treatment device. This method allows the low-pressure waste flash steam of the UHT plant to be reused instead of simply being released to the atmosphere. Using a flash steam recovery system such as that of the present invention, all 50% of the waste steam can be recovered and reused, therefore, the injection chamber only needs to be filled with external live steam during the start-up sequence. Therefore, in this aspect of the present invention, after start-up, injection chamber heating can be performed with reused steam without an external live steam supply. In a first possible embodiment of the second aspect, the compressor configuration includes at least two compressor devices, alternatively three compressor devices, alternatively four compressor devices arranged in series, and the flash vapor is compressed piecewise by the compressor devices. Such a solution facilitates staged mechanical compression of the flash vapor. In certain embodiments, when the compressor devices are connected in series, the connection includes water injection.

[0032] In a second possible embodiment of the second aspect, at least two of the steps are carried out simultaneously.

[0033] In a third possible embodiment of the second aspect, the method further comprises the step of feeding the flash vapor through a thermal vapor recompression device after compressing the flash vapor in the compressor arrangement and before feeding the flash vapor into the thermal treatment apparatus.

[0034] In a fourth possible embodiment of the second aspect, the thermal processing apparatus includes a steam injection chamber.

[0035] In a fifth possible embodiment of the second aspect, the thermal treatment apparatus comprises a steam injector device.

[0036] These and other objects are achieved by the features of the independent claims. Further embodiments are evident from the dependent claims, the description and the drawings.

[0037] These and other aspects of the present invention will be apparent from the drawings and embodiments described below.

[0038] The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the invention, the drawings illustrate embodiments of the invention. It is to be understood, however, that the invention is not limited to the exact arrangements, examples, and equipment shown. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a schematic diagram of an embodiment of an ultra-high temperature processing plant. [Figure 2] 2 is an orthogonal view of an impeller and translucent impeller housing suitable for use in a compression device in the ultra-high temperature processing plant of FIG. 1. FIG. [Figure 3] 2 is a cross-sectional view of a compression device with an attached impeller and impeller housing suitable for use in the ultra-high temperature processing plant of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0040] In general, embodiments of the compression device described herein are suitable for use with any system that includes a compression device. The compression device is suitable for use with an ultra-high temperature processing ("UHT") plant as described herein. For example, advantages of the compression device as described herein include providing energy savings in the generation of steam for food processing, allowing for sanitary cleaning of the impeller and impeller housing, and allowing the motor for the compression device to be separated from the food handling portion of the ultra-high temperature processing plant. A particular advantage of the compression device described herein is that it is suitable for use with a mechanical vapor recompression (MVR) process, which allows for energy savings in the reuse of steam. MVR can enable UHT plants to reduce evaporation energy use by 90% or more. MVR uses energy recovered from flash steam to mechanically generate reusable high-pressure / high-energy steam. From Boyle's Law, for gases, PV / T (pressure * It is known that the ratio (volume / temperature) is constant (PV / T=K). During the compression of vapor, the pressure and temperature increase. This allows the thermal energy to be reused. Energy normally lost in compression is recovered, leading to a highly efficient UHT process loop. These and other advantages are described herein. More specifically, embodiments of the compression device described herein are suitable for various types of process plants.

[0041] Specifically, in certain embodiments, the present disclosure provides a sterile sanitary vapor compressor device intended for use in an injection MVR loop. The compressor device is an integral part of a heat pump circuit that reuses flash vessel steam, thereby reducing fresh steam consumption and reducing energy consumption. In some embodiments, the compressor device can operate as a single compressor, but can also operate in series with other compressor devices, where some desuperheating is required. In some embodiments, when compressor devices operate in series, the compressor includes water injection before, within, or after the compressor. Additionally or alternatively, desuperheating may be achieved through heat exchange and / or gas injection. The gas may be, for example, CO2.

[0042] FIG. 1 shows a plant for ultra-high temperature processing of liquid foods. The liquid food can be any food in liquid form, but the plant disclosed herein is particularly useful for temperature-sensitive foods that must be heated only for a short period of time to kill bacteria and preserve their flavor, consistency, and nutritional quality. Examples of such liquid foods are milk, milk-based products, baby food, liquid baby food concentrates, or nutritional drinks. The liquid food may have a high dry matter content (40% or more) and / or a high protein content (6% or more). The fluid food is initially stored in tank 22. Tank 22 is connected to sterilization loop 23, where the food is sterilized. The fluid food is transferred from tank 22 to thermal processing unit 1 via conduit 2 and pumps 24 and 25. Along the way, conduit 2 is connected to plate heat exchanger 26 for preheating the fluid food from about 1° C. to about 100° C., or more specifically, from about 5° C. to about 75° C.

[0043] The fluid food enters the heat treatment device 1, e.g., the steam injection chamber, as a bundle of separate liquid food jets 7 through multiple openings in a nozzle at the top of the steam injection chamber 1. High temperature steam is injected into the steam injection chamber 1 through a steam inlet, e.g., a circumferential steam distribution chamber. In the steam injection chamber 1, the liquid food jets meet the high temperature steam and the food is thereby heated and absorbs the steam.

[0044] In an embodiment, heat treatment apparatus 1 includes a steam injector device instead of a steam injection chamber. The steam injector device heats food by mixing the food from conduit 2 with steam from conduit 14 and / or conduit 3 inside the steam injector device. However, the following description will refer only to the steam injection chamber for simplicity.

[0045] The steam injection chamber 1 is preferably essentially rotationally symmetric about a vertical axis. The upper section of the steam injection chamber 1 has a hollow cylindrical portion and a top portion shaped similar to a truncated cone. The bottom section is releasably connected to the upper section by a flanged connection to allow access to the interior of the steam injection chamber 1 for cleaning and / or maintenance. The bottom section, in an embodiment, has a shape similar to a truncated cone.

[0046] Additionally, steam injection chamber 1 is connected to conduits 4 and 5, which are used to deliver and remove a liquid, e.g., water, to cool the bottom of steam injection chamber 1. A cooling jacket, connected to conduits 4 and 5, may be provided around the bottom section. The cooling jacket keeps the bottom section cool to prevent or minimize smearing or burning of liquid food that contacts the interior walls of the bottom section. The cooling jacket provides a mantle of cooling water or other cooling medium around the bottom section. The mantle is divided by a spiral cross wall that directs the cooling water in a spiral pattern around the bottom section. The cooling medium inlet passes through the pump housing and enters a portion of the mantle that also extends into the pump housing. From this portion internal to the pump housing, the cooling medium's spiral path continues spirally upward toward the cooling medium outlet, connected to conduit 5 at the top of the cooling jacket and near the top of the bottom section. The liquid food jet terminates on the funnel-shaped interior wall of the bottom section. The bottom section collects the liquid food from the liquid food jet and guides it to an outlet opening at the lower end of the steam injection chamber 1 which is also the lower end of the bottom section and the inlet of the pump 6 .

[0047] The lower portion of the bottom section forms the outlet opening of the steam injection chamber 1, which in one embodiment connects seamlessly to the inlet of the pump 6 and in another embodiment simply connects to the pump 6. In one embodiment, this is achieved by having the lower end of the bottom section made from steel plate, such as stainless steel, and connected to the pump housing by welding. In an embodiment, the pump housing is provided with a circular ridge or circular upstanding flange that facilitates welding the pump housing to the lower end of the bottom section. After welding, the transition between the bottom section and the pump housing / pump inlet formed by the weld is machined to provide a perfectly smooth surface free of cracks or crevices that would be difficult to clean or rinse.

[0048] Pump 6 may be a centrifugal or positive displacement pump. Pump 6 is of a conventionally known type, for example a gear or lobe pump, and is connected to the outlet of steam injection chamber 1. The housing of pump 6 is provided with a temperature sensor in a location where the adjacent surfaces are kept clean from scorching, for example by gear teeth or rotor lobes. In this way, reliable control of the plant can be ensured. In another embodiment, the temperature sensor is a pin probe sensor located immediately after pump 6 at the start of conduit 9. The outlet of pump 6 is connected by conduit 9 to the inlet of a flash vessel 10, for example a vacuum chamber, of a conventionally known type. In one embodiment, conduit 9 includes a valve at its end just before flash vessel 10.

[0049] Flash vessel 10 is adapted to remove water added to the fluid food product during heat treatment in steam injection chamber 1. Excess water added by steam during heat treatment is removed through steam conduit 8. The concentrated fluid food product is discharged through conduit 12 and pump 13 in a manner known in the art and transferred to aseptic homogenizer 17. The homogenized fluid food product is then cooled, for example, from about 75°C to about 20°C in one or several plate heat exchangers 21, and transferred to storage unit 19 or a packaging process. In another example, the homogenized fluid food product is cooled from a temperature as high as 95°C to room temperature, about 20°C, or a refrigerated temperature, about 5°C, and transferred to storage unit 19 or a packaging process.

[0050] Plate heat exchangers 21 and 26 are connected in a continuous heating / cooling loop with a water heater 27 which heats the heating water just before it enters preheater 26 .

[0051] In the prior art, low-pressure steam, such as flash steam, is typically vented to the atmosphere or condensed in a cooling tower. Alternatively, the low-pressure waste steam can be mechanically compressed to a higher pressure so that it can be reused. Steam tables indicate that when steam condenses, approximately 25% of its heat remains in the condensate, i.e., the concentrated fluid food product. Using a flash steam recovery system such as that shown in Figure 1, approximately half of this heat can be recovered as flash steam. However, UHT processes require that the flash steam that comes into direct contact with the food product be of food quality.

[0052] Steam injection chamber 1 has a fluid food inlet located at the top of steam injection chamber 1, a fluid food outlet located at the bottom of steam injection chamber 1, and a first steam inlet also located at the top of steam injection chamber 1. By "top" we mean the upper section of the steam injection chamber, and by "bottom" we mean the lower section of the steam injection chamber as seen when the steam injection chamber is oriented so that it extends essentially vertically.

[0053] A heat-sensitive fluid food product is fed to the fluid food inlet by conduit 2 and is subjected to heat treatment in steam injection chamber 1 by feeding live steam and / or flash steam into steam injection chamber 1. "Live steam" refers to steam generated, for example, by a steam boiler. "Flash steam" refers to steam recovered from a flash vessel. Live steam is fed into steam injection chamber 1 through a first steam inlet by live steam conduit 3. The other end of steam conduit 3 is connected to a steam boiler. The steam boiler generates steam at approximately 7-20 bar. The pressure of the steam fed into steam injection chamber 1 is approximately 5 bar. Therefore, a control valve can be used to throttle the amount of steam, reducing the pressure from 7-15 bar to 5 bar. In a preferred embodiment, the turbocharger reuses this pressure drop as power to drive the turbocharger.

[0054] Flash vessel 10 has a fluid food inlet at the top of flash vessel 10 and a fluid food outlet at the bottom of flash vessel 10. "Top" refers to the upper section of the flash vessel, and "bottom" refers to the lower section of the flash vessel as viewed when the flash vessel is positioned so that it extends essentially vertically. The inlet at the top is a horizontal and tangential inlet at the top.

[0055] The fluid food outlet of the steam injection chamber 1 is connected by conduit 9 and pump 6 to the fluid food inlet of a flash vessel 10. The fluid food outlet of the flash vessel 10 is connected to a conduit 12 and pump 13 for discharging the fluid food from the flash vessel 10.

[0056] Flash vessel 10 includes a flash vapor outlet disposed in the upper portion of flash vessel 10. The flash vapor outlet is connected to first flash vapor conduit 8. When the flash vapor exits flash vessel 10, in certain examples, it has a temperature of about 70° C. and an absolute pressure of about 0.3 bar. In other examples, the flash vapor may have a temperature in the range of about 50° C. to about 90° C. and an absolute pressure in the range of about 0.1 bar to about 1.0 bar.

[0057] A first flash vapor conduit 8 is connected to the inlet of the compression arrangement 16 and is used to deliver flash vapor from the flash vessel 10 to the compression arrangement 16. The flash vapor is then compressed in the compression arrangement to about 2-10 bar, more specifically about 5-7 bar, and a temperature of about 100-200°C, more specifically about 130-170°C after desuperheating.

[0058] The outlet of the compression arrangement 16 is connected to a second flash steam conduit 14 used to transport flash steam to the steam injection chamber 1. In one embodiment, the second flash steam conduit 14 is connected to the live steam conduit 3 so that the live steam and flash steam are mixed before entering the steam injection chamber 1 through the first steam inlet. In another embodiment, the second flash steam conduit 14 is connected directly to a second steam inlet located at the top of the steam injection chamber 1. In this embodiment, the live steam is fed into the steam injection chamber 1 through the first steam inlet, and the flash steam is fed into the steam injection chamber 1 through the second steam inlet. Both of these embodiments may be combined.

[0059] Additionally, the second flash vapor conduit 14 can be connected to a compression device, such as a device for thermal vapor recompression 20, also known as a TVR. If the flash vapor has a lower than desired pressure, such as less than 5 bar, e.g., 4 bar, upon exiting the compression arrangement 16, a compression device, e.g., a thermal vapor recompression device, can be used to compress the flash vapor to a further desired pressure, e.g., 5 bar. In certain embodiments, the flash vapor exiting the compression device, e.g., the TVR, has a pressure greater than 5 bar. The thermal vapor recompression device 20 is connected to the second flash vapor conduit 14 and the live steam conduit 3. The thermal vapor recompression device compresses the flash vapor to approximately 1 to 7 bar, more preferably 1 to 3 bar.

[0060] The compression arrangement 16 includes one compression device 16a, two compression devices 16a, 16b connected in series, or three compression devices 16a, 16b, 16c connected in series. In certain embodiments, when connected in series, the flash vapor conduit 8 is connected to the inlet of the first compression device 16a, and the second flash vapor conduit 14 is connected to the outlet of the second compression device 16b and, optionally, the third compression device 16c. Alternatively, the flash vapor conduit 8 is connected to the inlet of the compression device 16a, and the second flash vapor conduit 14 is connected to the outlet of the same compression device 16a. In certain embodiments, the compression device is used in combination with another compression device, for example, a thermal vapor recompression device, connected to the second flash vapor conduit.

[0061] Compression devices 16a, 16b, and / or 16c may include steam compressors, heat pumps, or turbines. Turbines may be more efficient at transferring large volumes. Compression devices 16a, 16b, and / or 16c may also include turbochargers powered by steam provided by the control valve / steam boiler described above. Turbochargers can further increase energy savings because the energy used to drive the turbocharger is "free." As described above, the steam pressure from the steam boiler is much higher than the pressure required for the steam injection chamber 1. In today's prior art, a steam throttle valve is installed between the boiler and the steam injection chamber. This throttle valve reduces the steam pressure from 7-15 bar to 4 bar, with all of the high-pressure energy being lost as friction energy within the throttle. When using a turbocharger instead of a throttle valve, the high-pressure steam is directed through the turbocharger's driving turbine, thus providing nearly free power for driving the turbocharger. In certain embodiments, the compression device has a single screw compressor type configuration.

[0062] In certain embodiments, compression devices 16a, 16b, and / or 16c are of sanitary design. In other embodiments, when two or more compression devices are used in series, the plant is configured to provide inter-stage desuperheating. In some embodiments, when two or more compression devices are used in series, the two or more compression devices are connected to each other through connections that include water injection before, inside, or after each compressor.

[0063] Compression arrangement 16 may include two compression devices of the same type, such as two vapor compressors, or two compression devices of different types, such as a vapor compressor and a turbine. Alternatively, compression arrangement 16 may include three compression devices of the same type, such as three vapor compressors, or three compression devices of different types, such as a vapor compressor and a turbine. In addition, desuperheating may be used following some or all of the compression devices. In certain examples, water injection may be used, for example, to desuperheat the steam to saturated steam.

[0064] In the prior art, the first flash vapor conduit 8 would be connected to the condenser conduit 11 instead of the compression devices 16a, 16b. The condenser conduit 11 is connected to the condenser 15 and delivers the flash vapor to the condenser 15. The flash vapor is cooled in the condenser and then discharged to the atmosphere.

[0065] Without being bound by theory, it is believed that the compressor device of the present disclosure reduces the amount of energy used in the injection system, especially when used in series. Unlike the compressor device of the present disclosure, currently used indirect heat pump solutions do not provide the required energy efficiency, and indirect heat pumps do not provide water reduction. Conventional indirect heat pump solutions typically have an efficiency of COP=2 for UHT systems. Therefore, the direct recompression disclosed herein advantageously has an improved efficiency of COP=4.

[0066] The UHT plant operates according to the following method. The method includes several steps performed in a continuous loop. However, at least two of these steps are performed simultaneously. A fluid food product is fed into the steam injection chamber 1. Simultaneously, live steam is fed into the steam injection chamber 1 through the first steam inlet, and flash steam is fed through either the first steam inlet or the second steam inlet so that the fluid food product is thermally treated by the live steam and flash steam. After thermal treatment, the fluid food product is removed from the steam injection chamber 1 and fed into the flash vessel 10. After treatment, the condensed fluid food product is removed from the lower section of the flash vessel 10. Simultaneously, flash steam is removed from the upper section of the flash vessel 10. The flash steam is then fed to the compressor arrangement 16. The compressor arrangement 16 compresses the flash steam from approximately -0.7 bar to approximately 5 bar. The flash steam is compressed piecewise by two compressor devices 16a, 16b connected in series. Alternatively, the flash vapor is compressed piecewise by three or four compressor devices 16a, 16b, 16c connected in series.

[0067] After compression, the flash vapor is pumped into injection chamber 1. In one embodiment, the method further includes pumping the flash vapor through a thermal vapor recompression device 20 after compressing the flash vapor in compressor arrangement 16 and before pumping the flash vapor into vapor injection chamber 1.

[0068] 2-3 below illustrate a particular embodiment of a compression device 16a suitable for use in a plant for processing fluid food products as described herein. It is an advantage of this embodiment that the compression device 16a is a high-temperature and high-pressure compressor. For purposes of this disclosure, the term "high-temperature compressor" is defined as a compressor having an inlet temperature of 70-90°C and an outlet temperature after desuperheating of 120-170°C. In contrast, conventional mechanical compressors operate at temperatures below 50°C. As used herein, the term "high-pressure compressor" refers to a compressor having a pressure ratio ("PR") in the range of 11-20. In contrast, conventional mechanical compressors operate at a PR of less than 2.

[0069] Generally, the compression device 16a shown in Figures 2-4 is aseptic and / or hygienic. For example, the hygienic design defines contact surfaces as having a surface roughness of 0.8-1.2 Ra and easy clean-in-place ("CIP") capability, allowing for cleaning of the inside of the contact surfaces without disassembly. Because of the very high cleaning speeds (>5 meters / second), the hygienic geometric design requirements (maximum radius and maximum surface roughness) are slightly below the U.S. 3A regulations and the European Hygienic Engineering and Design Group ("EHEDG") guidelines, yet still provide a fully CIP-cleanable compressor. Additionally, the compression device 16a is believed to have no visible or exposed threads, bolts, or nuts inside the compressor process room, contributing to a hygienic compressor design.

[0070] Although other compressible fluids such as CO2 are contemplated, in a preferred example, compression device 16a is configured to compress only vapor, and compression device 16a may optionally utilize vapor as an indirect medium.

[0071] FIG. 2 is an orthogonal view of an impeller 28 and translucent impeller housing 29 suitable for use in compression devices 16a, 16b, and / or 16c in the UHT plant of FIG. 1. For simplicity, FIGS. 2-3 will be described with reference to compression device 16a; however, compression devices 16b and / or 16c may be the same or different, and compression configuration 16 may include additional compression devices. As shown in FIG. 2, compression device 16a includes an inlet 30 and an outlet 31. Inlet 30 is axial, and outlet 31 is radial. In response to rotation of impeller 28, flash steam introduced through inlet 30 is accelerated radially. In a commonly understood manner, the radially accelerated steam is driven toward the outlet with sufficient energy to compress the steam. Compression of the steam results in an increase in temperature, i.e., the flash steam can gain energy so that it can be pumped back into live steam conduit 3, as shown in FIG. 1.

[0072] 2 through the blade configuration of impeller 28, impeller 28 is configured to function, for example, as a centrifugal high-speed compressor impeller. For purposes of this disclosure, the term "centrifugal high-speed compressor impeller" refers to an impeller configured to rotate at greater than 20,000 revolutions per minute ("rpm"). These rotational speeds are an order of magnitude greater than mechanical vapor recompression machines for conventional evaporators, which operate at speeds below 3000 rpm.

[0073] In certain embodiments, compressor devices 16a, 16b, and / or 16c are configured such that impeller 28 rotates between 20,000 rpm and 75,000 rpm, alternatively between 35,000 rpm and 45,000 rpm, alternatively between 40,000 rpm and 42,000 rpm. The tip speed of impeller 28 is configured to be greater than 300 meters / second ("m / s"), for example, the tip speed may be, for example, between 400 and 580 m / s, or preferably between 450 and 550 m / s.

[0074] The compressor device of the present disclosure is of sanitary design. Specifically, the impeller housing 29 and impeller 28 facilitate aseptic and / or sanitary cleaning of the impeller housing 29 and impeller 28, thereby allowing the device to be sanitary. In this regard, the impeller housing 29 can be removably secured to a housing mounting plate 34 via a series of bolts (not shown). The housing mounting plate 34 can be part of a partition or chamber that separates the motor 32 from the food handling area. This can facilitate ease of cleaning and extend the life of the motor 32 by reducing exposure to cleaning fluids. This benefit of separating the motor 32 from the impeller housing 29 and food handling area is further enhanced by the axial inlet 30 and radial outlet 31. That is, the redirection of steam from the axial to the radial direction can help facilitate isolating the motor 32 from the food handling area of ​​the UHT plant.

[0075] FIG. 3 is a cross-sectional view of a compression device 16a having an impeller 28 and impeller housing 29 according to another embodiment. The compressor device 16a shown in FIG. 3 is similar to the compressor device 16a described above in this specification; that is, for the sake of brevity, those features already described will not be described again. The example impeller housing 29 shown in FIG. 3 can be secured to the motor 32 through the back side of the housing mounting plate 34. In this manner, the vapor process side can be cleaned without the cleaning medium entering the motor compartment. As also shown in the cross-section of the impeller housing 29 in FIG. 3, a recovery conduit 36 ​​is configured to recover vapor driven outward through rotation of the impeller 28. The increasing cross-sectional area of ​​the recovery conduit 36 ​​is illustrated in FIG. 3 as well as in FIG. 2.

[0076] The shaft seal for the compression device 16a may include a shaft seal type in which the sealing medium flows only in the axial direction, toward the process side (impeller room), which is different from conventional compressors.

[0077] It should be noted that various contact surfaces of the compression device 16a can be configured for sanitary food contact. For example, the material used for the impeller 28 and impeller housing 29 can be stainless steel or other such material suitable for use with food contact. The surface finish can be suitably smooth, and the internal radius can be suitably large to facilitate CIP operation. Additionally, internal threads, "dead legs," or pockets can be eliminated from the compression device 16a.

[0078] The present invention has been described herein with reference to various embodiments. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art, from a study of the drawings, the present disclosure, and the appended claims, when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Reference signs used in the claims should not be interpreted as limiting the scope.

[0079] It should be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. It should also be noted that the claims may be drafted to exclude any optional element. Accordingly, this language is intended to serve as a predicate over the use of limiting terms such as "solely" and "only" in connection with the recitation of claim elements or over the use of a "negative" limitation.

[0080] Each of the individual embodiments described and illustrated herein has individual components and features that may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the invention. Any described method can be carried out in the order of events described or in any other order that is logically possible.

[0081] As used herein, the term "about" when referring to measurable values ​​such as amounts, temporal durations, and the like, is meant to encompass variations of ±20% or ±10%, more preferably ±5%, even more preferably ±1%, and even more preferably ±0.1% from the specified value when such variations are appropriate for carrying out the methods disclosed herein.

[0082] As used herein, the terms "comprising," "including," "containing," and "characterized by" are interchangeable, inclusive, and open-ended and do not exclude additional, unrecited elements or method steps. Any recitation herein of the term "comprising," particularly in the description of a component or composition or in the description of an element of a device, is understood to encompass components and methods consisting essentially of and consisting of the recited component or element.

[0083] As used herein, the term "consisting of" excludes any element, step, or ingredient not specified in the claimed element.

[0084] Where a range of values ​​is provided, unless the context clearly indicates otherwise, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value within that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0085] The many features and advantages of the present invention are apparent from the detailed specification, and it is the intention of the appended claims to cover all such features and advantages of the present invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and therefore, all suitable modifications and equivalents shall be deemed to fall within the scope of the invention. [Explanation of symbols]

[0086] 1. Heat treatment equipment 2 conduit 7 Liquid Food Jet 23 Sterilization Loop 24, 25 Pumps 26 Plate Heat Exchanger

Claims

1. 1. A sanitary compression device comprising: an impeller housing having an axial inlet and a radial outlet, the axial inlet receiving flash steam from a flash steam outlet of a food system flash vessel, and the radial outlet supplying compressed flash steam to a heat treatment device; an impeller disposed in the impeller housing; a motor configured to rotate the impeller, wherein flash steam entering the inlet is radially accelerated and compressed in response to rotation of the impeller; a compression device, including

2. 10. The compression device of claim 1, wherein the motor is configured to rotate the impeller faster than 20,000 revolutions per minute (rpm).

3. 3. The compression device of claim 1 or claim 2, wherein the tip speed at the outer periphery of the impeller is greater than 300 meters per second (m / s).

4. 4. The compression device of any one of claims 1 to 3, configured to generate a saturated steam temperature at the radial outlet of 120 to 170°C.

5. 5. A compression device according to any one of claims 1 to 4, configured to generate a pressure ratio at the radial outlet of the last compressor relative to the pressure at the axial inlet of the first compressor in the range of 11 to 20.

6. 6. The compression device of any one of claims 1 to 5, configured to facilitate cleaning in place (CIP) without disassembly.

7. further comprising a housing mounting plate disposed between the motor and the impeller housing; 7. The compression device of claim 1, wherein the motor is isolated from the impeller and the impeller housing to facilitate aseptic sanitary cleaning of the impeller and the impeller housing without exposing the motor to cleaning fluids used in aseptic cleaning.

8. A plant for the thermal treatment of fluid food products comprising a compression device according to any one of claims 1 to 7.

9. 9. The plant of claim 8, comprising two compression devices connected in series.

10. 9. The plant of claim 8, comprising three or four compression devices connected in series.

11. 11. A plant according to any one of claims 8 to 10, including water injection before, within or after the compressors connected in series to prevent overheating of the fluid food product.

12. 12. A plant according to any one of claims 8 to 11, wherein a steam compressor is removably mounted on the plant.

13. 13. The plant of claim 12, wherein the vapor compressor is configured to enable aseptic sanitary cleaning of the plant.

14. 1. A method for compressing flash steam generated in an ultra-high temperature processing plant having a heat treatment device in which a fluid food product is subjected to heat treatment through compressed flash steam, comprising: feeding the fluid food product into the thermal processing device; feeding live steam and / or flash steam into the heat treatment device; removing the fluid food product from the heat treatment device; delivering the fluid food product into a flash vessel; removing the fluid food product from the flash vessel; removing flash vapor from said flash vessel; delivering the flash vapor to a sanitary compressor arrangement having a compression device, the compression device comprising: an impeller housing having an axial inlet and a radial outlet, the axial inlet receiving flash steam from a flash steam outlet and the radial outlet supplying compressed flash steam to a flash steam conduit; an impeller disposed in the impeller housing; and a motor configured to rotate the impeller, wherein flash steam entering the inlet is radially accelerated and compressed in response to rotation of the impeller, and wherein the sanitary compressor arrangement compresses the flash steam after it is delivered into the heat treatment device; the delivering step including: A method comprising:

15. 15. The method of claim 14, wherein the ultra-high temperature processing plant includes two compression devices arranged in series, and the flash vapor is piecewise compressed by the two compression devices.

16. 15. The method of claim 14, wherein the ultra-high temperature processing plant comprises three or four compression devices arranged in series, and the flash vapor is piecewise compressed by the three or four compression devices.

17. 17. The method of claim 15 or claim 16, further comprising desuperheating before, within, or after the serially arranged compression devices.

18. 18. The method of claim 17, wherein the desuperheating step comprises water jet cooling or cooling by a heat exchanger.

19. 15. The method of claim 14, wherein the compression device is cleaned by wash-in-place cleaning of only the impeller and impeller housing without cleaning the motor.

20. 1. A plant for the thermal treatment of fluid food products, comprising: a heat treatment device (1) with a fluid food inlet located at its top; a fluid food outlet located at the bottom of the heat treatment device (1); a first steam inlet arranged at the top of the heat treatment device (1), wherein the fluid food is subjected to heat treatment by feeding live steam and / or flash steam into the heat treatment device (1), the live steam being fed into the heat treatment device (1) by a live steam conduit (3) connected to the first steam inlet; a flash vessel (10) having a fluid food inlet at the top of the flash vessel (10) and a fluid food outlet at the bottom of the flash vessel (10), the fluid food outlet of the heat treatment device (1) being connected to the fluid food inlet of the flash vessel (10) by a conduit (9) and a pump (6), the fluid food outlet of the flash vessel (10) being connected to a conduit (11) for discharging the fluid food from the flash vessel (10); 2) and a pump (13), the flash vessel (10) further comprising a flash steam outlet located at the top of the flash vessel (10), the flash steam outlet being connected to a first flash steam conduit (8), the first flash steam conduit (8) being connected to an inlet of a compression arrangement (16) for delivering the flash steam to the compression arrangement (16) where the flash steam is compressed, and a second flash steam conduit (14) being connected to an outlet of the compression arrangement (16) for transporting the flash steam to the heat treatment device (1); Including, The compressor configuration is as follows: an impeller housing having an axial inlet and a radial outlet, the axial inlet receiving flash steam from the flash steam outlet and the radial outlet supplying compressed flash steam to the second flash steam conduit; an impeller disposed in the impeller housing; a motor configured to rotate the impeller, wherein flash steam entering the inlet is radially accelerated and compressed in response to rotation of the impeller; A compressor configuration that can be hygienically cleaned; Including, plant.

21. the compression device further includes a housing mounting plate disposed between the motor and the impeller housing; the motor is isolated from the impeller and the impeller housing to facilitate aseptic cleaning of the impeller and the impeller housing without exposing the motor to cleaning fluids used in aseptic cleaning; 21. The plant of claim 20.

22. 22. The plant of claim 20 or claim 21, wherein the impeller housing and impeller are cleaned independently of the motor by sanitary cleaning of the impeller housing and impeller.

23. 22. The plant of claim 20 or claim 21, wherein the compression arrangement further comprises a plurality of compression devices.

24. 24. The plant of any one of claims 20 to 23, further comprising a water injection device positioned before, within, or after the compression device to desuperheat the compressed flash steam.

25. 25. The plant of any one of claims 20 to 24, further comprising an aseptic design for UHT sterilized food products.

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