Technical Field

The present invention relates to a vessel system, in particular for use in liquid product processing such as liquid food processing. More particularly, the present invention relates to a flash vessel system.

Background

Vessels are commonly found in processing lines for liquid products, such as in liquid food processing plants. The use of vessels may vary, however they are suitable for enclosing a specific volume of the liquid of food product at given physical conditions, such as pressure, temperature, etc.

In liquid product processing, it may be desirable to provide instant sterilization of the liquid product. This may be done by means of a steam injector which provides a hot flow of water vapor into an existing flow of non-sterilized liquid product. Due to the increased temperature of the liquid product, sterilization will occur. However, the excess water content should preferably be removed, for which purpose the sterilized liquid product enters a flash vessel. Here, the temperature and the pressure drop instantly, whereby the excess water in the form of steam is boiled off.

When liquid product flows into the flash vessel, heavily boiling occur.

Therefore, the flow velocity of the liquid product increases. If the liquid product contains particles it is thus possible that the inner walls of the vessel will be subject to wear. Such risk significantly increases if the velocity of the particles increases. That is, the higher throughput of the flash vessel, the higher risk for wear and damage.

Hence, there is a need for an improved vessel system reducing the risk of particle-induced wear of the inner walls of the vessel.

Summary

An object of the present invention is to provide a vessel system solving the above-mentioned drawbacks of prior art solutions.

An idea of the present invention is to provide a vessel system, of which an inlet channel for the liquid product is configured to reduce the velocity of the incoming liquid product.

According to a first aspect, a vessel system is provided. The vessel system comprises a vessel connected to a liquid product inlet channel, a vacuum system, and a liquid product outlet channel. The vessel system further comprises a recirculation channel connecting the outlet channel to the vessel, optionally via said inlet channel such that at least some part of the liquid product exiting the vessel through the outlet channel will be re-introduced into the vessel.

The vessel system may further comprise an exit pump for drawing liquid product out from the vessel.

The re-circulation channel may connect to the outlet channel downstream said exit pump. Further to this, the re-circulation system may comprise a flow control valve.

According to some embodiments, the re-circulation system connects to the vessel, optionally via the inlet channel at a flow combination section for combining a first flow of initial liquid product with a second flow of re-circulated liquid product.

According to some embodiment, the re-circulation system connects to the inlet channel at a flow combination section for combining a first flow of initial liquid product with a second flow of re-circulated liquid product, wherein the flow combination section is configured such that the flow direction of the first flow is different from the flow direction of the second flow.

The vacuum system may comprise a vacuum pump for reducing the pressure inside said vessel. Alternatively, and for the same purpose, the vacuum system may comprise a condenser to condensate the steam.

According to a second aspect, a sterilization unit for a liquid product

processing line is provided. The sterilization unit comprises a vessel system according to the first aspect.

According to a third aspect, a method for a vessel system comprising a vessel connected to a liquid product inlet channel, a vacuum system, and a liquid product outlet channel is provided. The method comprises the steps of providing a first flow of liquid product to said vessel via said liquid product inlet channel; providing a second flow of liquid product from said vessel via said liquid product outlet channel; and recirculating at least some of the liquid product from the second flow to the vessel, optionally via the liquid product inlet channel.

The method may further comprise the step of flash cooling the liquid product enclosed in said vessel by means of the vacuum system.

Brief Description of Drawings

Preferred embodiments of the present invention will now be described in greater detail herein below with reference to the accompanying drawings, in which:

Fig.1 is a schematic cross-sectional view of a vessel system according to an embodiment;

Fig. 2a is a schematic top-view of a vessel system according to an

embodiment; Fig. 2b is a schematic top view of a vessel system according to another embodiment;

Fig. 3 is a schematic cross-sectional view of a liquid product inlet channel of a vessel system according to an embodiment; and

Fig. 4 shows a method according to an embodiment.

Detailed Description

Starting with Fig. 1 parts of a sterilizing unit 10 are shown, wherein said parts forms a vessel system 100. The vessel system 100 is preferably arranged

downstream a steam injection unit (not shown), configured to inject hot steam into the liquid product for sterilizing the liquid product prior to packaging. The vessel system 100 provides flash cooling of the sterilized liquid product, whereby the injected water content will be removed from the liquid product in a controlled manner.

The vessel system 100 comprises a vessel 1 10 having a liquid product inlet channel 120. The inlet channel 120 connects to the vessel 1 10 such that liquid product is allowed to flow into the vessel 1 10. In some embodiment the inlet channel 120 is provided with a flow control valve (not shown).

Further to this the vessel system 100 comprises a liquid product outlet channel 130 that connects to the vessel 1 10 such that liquid product is allowed to flow out from the vessel 1 10. In order to draw liquid product out from the vessel 1 10 the outlet channel 130 is provided with an exit pump 132.

The vessel system 100 further comprises a vacuum system 140, comprising a vacuum pump 142. The vacuum system 140 connects to the vessel 1 10 such that a low pressure may be provided inside the vessel 1 10.

Hence, when hot liquid product enters the vessel 1 10 the low pressure will cause boiling, whereby the water content of the liquid product will be reduced to a level being similar to the water content before steam injection.

In accordance with the embodiments described herein the vessel system 100 further comprises a re-circulation channel 150. The re-circulation system connects the outlet channel 130 to the inlet channel 120 such that at least some part of the liquid product exiting the vessel 1 10 through the outlet channel 130 will be reintroduced into the vessel 1 10. Preferably, the re-circulation channel 150 is provided with a flow control valve 152 for controlling the amount of discharged liquid product to re-enter the liquid product inlet channel 120.

The re-circulation channel 150 is provided in order to reduce the velocity of liquid product flowing in the inlet channel 120, and especially in order to reduce the velocity of particles present in the liquid product. High speed of particles has proven to be a significant reason for wear on the inner walls of the vessel 1 10, whereby a reduction in particle velocity will assist in preventing damage and malfunction of the vessel 1 10.

When re-circulated liquid product enters the inlet channel 120, i.e. at a position upstream the inner walls of the vessel 1 10, a wall, or curtain, of the re-circulated liquid product will slow down the incoming liquid product before it hits the inner walls of the vessel 1 10.

Now turning to Fig. 2a, an embodiment of the vessel system 100 is shown. Fig. 2a shows a cross-section of the vessel system 100 from above, and shows a flow combination section 1 60 at the inlet channel 120, at which a first flow of initial liquid product is at least to some extent combined with a second flow of re-circulated liquid product. The flow combination section 1 60 is configured such that the flow direction of the first flow is guided downwards by a slit formed along the dashed line in Fig. 2a. The re-circulated liquid product, i.e. the second flow, will thus form a curtain along the complete wear area close to the inner walls of the vessel. Hence, the second flow of re-circulated liquid product will flow to form almost a film on the inner walls of the vessel 1 10.

In Fig. 2b another embodiment is shown. Similar to Fig. 2a, Fig. 2b shows a cross-section of the vessel system 100 from above, and shows a flow combination section 1 60 at the inlet channel 120, at which a first flow of initial liquid product is combined with a second flow of re-circulated liquid product. The flow combination section 1 60 is configured such that the flow direction of the first flow is different from the flow direction of the second flow. The re-circulated liquid product, i.e. the second flow, will thus form a curtain upstream the vessel 1 10. Hence, the second flow of recirculated liquid product will flow to form a shadow with a distance to the inner walls of the vessel 1 10.

The flow combination section 1 60 may thus be constructed by a simple modification of the inlet channel 120. The position and arrangement of the flow combination section will thereby determine how the flow of re-circulated liquid product will reduce the velocity of incoming liquid product. Preferably, the flow combination section 1 60 is a fixed construction.

In Fig. 3 a cross-section of the inlet channel 120 is shown, taken in the direction fo the flow of incoming liquid product. The dashed area illustrates how the flow of re-circulated liquid product is distributed to form the curtain for reducing the velocity of the incoming liquid product, and especially the velocity of particles present in the liquid product.

Again returning to Fig. 1 , the flow control valve 152 of the re-circulation channel 150 may be connected to a controller 170. The controller 170 is configured to control the operation of the flow control valve 152, such that the amount of re- circulated liquid product may be determined accurately. Should the incoming liquid product have a high amount of hard particles, it may be desired to re-circulate a higher amount in order to achieve the desired reduction of velocity. Correspondingly, a liquid product having only a very small amount of soft particles may only require a very low amount of re-circulated liquid product. From above the controller 170 preferably has one or more input channels (not shown), receiving information of e.g. liquid product constitution, velocity, pressure, temperature, etc. Upon receiving information specifying the liquid product and its conditions, the controller 170 may control the flow control valve 152, and hence the velocity reduction, in an efficient and accurate manner. The flow control valve 152 is thus preferably used for adjusting the operation of the vessel system 100 based on the specific product to be

processed.

Now turning to Fig. 4 a method 200 for a vessel system 100 will be described. The vessel system 100 comprises a vessel 1 10 connected to a liquid product inlet channel 120, a vacuum system 140, and a liquid product outlet channel 130 in accordance with the description above. The method 200 comprises a first step 202 of providing a first flow of liquid product to said vessel via said liquid product inlet channel. A second step 204 is performed in which a second flow of liquid product from said vessel via said liquid product outlet channel is provided. The method 200 further comprises a third strep 206 of re-circulating at least some of the liquid product from the second flow to the liquid product inlet channel. In a preferred embodiment, the method further comprises a step 208 of flash cooling the liquid product enclosed in said vessel by means of the vacuum system.

The invention has mainly been described with reference to a few

embodiments. However, as is readily understood by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended claims.