DE19902610C1 - Pasteurization of products by injection of several streams of steam at right angles to product flow at following points in flow line. - Google Patents

Abstract

A steam injection module (4) consists of a steam pipe crossing the product line along a diameter of the latter. Injection holes are drilled into the steam pipe where it crosses the product line. A number of these modules are placed along the product line in a manner that passes the steam lines along differently oriented diameters of the product line. Static mixing disks may be placed between modules. Steam lines are individually controlled. The lines are cleaned between batches by passing cleaning material through them either from valve (17) or valve (14). All foodstuffs capable of being pumped can be treated and hence the material for the product line is preferably polytetrafluoroethylene (PTFE) to reduce friction. The steam line is also plastic and welded to the product line for reasons of hygiene. Steam at about 150 deg C is used. A treatment over 120 hours can be carried out without the need to clean the installation.

Description

The invention relates to a method and an apparatus for Pasteurization / sterilization of liquid to highly viscous, pumpable, continuously pre-conveyed products by di right steam injection at temperatures up to 150 ° C.

The products to be heated come from the food, chemical or pharmaceutical industry. With food it is preferably a matter of heating processed cheese, Soups or sauces with and without lumpy inlays.

In order to achieve optimal steam incorporation, a possible as large a product surface as possible. For this are in the prior art various methods and devices in Commitment:

In a first known embodiment, the injection takes place tion of the steam via individually controlled, mostly as steam return Impact valves designed steam nozzles or individually controlled Steam valves. By trained as a spiked roller or snail The driven mixing tool is intended to cover the product surface  enlarged and thus improves the condensation of the steam the. The disadvantage of this method is that of the drive motor, hygienic seals and the one to be applied Driving energy caused high costs. On the other hand, it is maximum temperature through the available shaft seals borders. Production is at risk of burning products time between the required cleaning in the hour range. In addition, particles containing products are used of the mixing tools partially destroyed.

In a second known embodiment, the Steam supply through a double jacket. The steam is through Drilled holes in the product-carrying pipe injected into the product. Each steam incorporation is carried out according to product viscosity powered mixing tools supported. In addition to the above Disadvantages listed here there is also the risk that especially at low vapor pressures and lower Performance individual steam holes clog and the product on burns.

In a third known embodiment, the Steam supply via a steam pipe protruding into the product the holes of which the steam is injected into the product. So far required, can be via a downstream static Mixer steam incorporation can be improved. The disadvantage is here that especially at low steam pressures and low performance can clog individual steam holes, and that Product burns on the steam pipe. If product in the steam pipe penetrates, this is difficult to clean afterwards In addition, a static leads to highly viscous products Mixer too high pressure, which limits the pro production performance, cf. in particular US 4851250 A.

All of the above-described embodiments depend on The product can only be described as hygienic to a limited extent.

The invention is based, described above bene procedures regarding the dangers of steam injector stop improve and / or product burns and the to Simplify the use of upcoming devices in their construction.

Based on the method described at the beginning, this is Object achieved according to the invention in that the product is on ner conveyor line successively by several from each other stood, individually connectable to a steam supply and forming a mixing section between them Steam injection modules is pumped, the product flow in each steam injection module divided into its cross section and in the separation level thus formed in each of the steam supply closed steam injection module with steam jets becomes.

With regard to the device, the above-mentioned object is achieved according to the invention by the following features:

• a) a product line in which at least one feed pump for Product promotion is switched;
• b) the product line is separated by several dete and between each a mixed section forming steam injection modules;
• c) each steam injection module has at least one across Product conveying direction and thus radially through the free Conveying cross-section of the product line a steam supply line connectable steam pipe that in the area of the product line cross section with steam out step holes is provided.

A major advantage in the inventive solutions can be seen in that on powered tools can be completely dispensed with. The use of several,  individually switched steam injection modules leads to a particular steam distribution. In addition, this also means that the Production performance ensured by adequate Blockage of the bores is excluded. In addition, the injector area can be additionally installed Steam injection modules in the performance size to changed Conditions, e.g. B. to a production output to be increased be fit. The size of the steam injection modules can be in Select dependence on product viscosity and throughput len. By arranging the with the steam outlet holes steam pipe provided radially to the product stream becomes a cereal Development of the product to increase the surface area for the steam finjection reached. This gives the number of injections bores per module also depending on the product viscosity and throughput. To optimize the steam ver division, the injection holes can be cylindrical or be designed with a conical outlet. The arrangement of the injek Drilling holes in the steam pipe are made depending on the product requirements Are the injection holes perpendicular to the product flows direction, this will improve the division of the Product reached by the steam jets. Are the injek tion holes in the direction of flow, it becomes an injector effect that causes pressure losses in highly viscous products can partially compensate.

In order to achieve further product division, it is advisable if the named parting plane of a subsequent steam injection tion module compared to that of the previous steam injection mo duls rotated by a few degrees in relation to the conveying direction or when the steam pipe of a subsequent steam injection tion module compared to that of the previous steam injection mo duls rotated by a few degrees around the product line axis is.  

For buildup and burns in the product line and / or to avoid on the steam pipe and to minimize pressure losses, it is useful if at least the inner surface of the Product management one related to the product to be promoted rige coefficient of friction. For this it is advantageous if both the product line and the steam pipe are made of art fabric, preferably PTFE or PFA.

To achieve a gap-free USDA and FDA-compliant execution form (USDA: United States Department of Agriculture; FDA: Food and Drug Administration) it is useful if each Pressure injection module a product made of plastic Has line section that penetrate with it across the steam pipe, also made of plastic, is welded is.

According to the invention, product heating up to a tem temperature of 150 ° C with optimal steam incorporation and lowest possible contamination and burns ren. In practical tests it was found that Pro Production downtimes of up to 120 hours without interim cleaning allow to achieve. According to the invention Increase system availability and reduce cleaning costs.

Further features of the invention are the subject of the dependent claims che and are together with other advantages of the invention explained in more detail using exemplary embodiments of the invention.

In the drawing, some are exemplary embodiments Shapes of the invention shown schematically. Show it:

Fig. 1 is a system modules for heating pumpable products with five series-connected steam injection;

FIG. 2 shows a system according to FIG. 1 with two injector areas which are separated from one another via an intermediate conveying pump and which have three or two steam injection modules;

Fig., Broken up 3 in a diagrammatic representation in part, a steam injection module;

Fig. 4 be a static mixing tool in the form of a plastic disk provided with through openings;

Fig. 5, the steam injection module according to Fig. 3 in a horizontal middle section and

Fig. 6 shows the object of FIG. 5 in a diagrammatic representation.

The system according to FIG. 1 has a storage container 1 to be heated, pumpable product, from which the product is pumped via a feed pump 3 connected into a product line 2 into a first steam injection module 4 , via a subsequent mixing section 5 and four more in succession switched steam injection modules 4 is promoted. The product emerging from the last steam injection module 4 flows through a heat holding section 6 via a pressure control unit (not shown in more detail) into a relaxation area (also not shown in more detail).

The five steam injection modules 4 are connected in parallel to a steam supply line 7 , which is equipped with a shut-off valve 8 and a steam control valve 9 . In addition, a shut-off valve 11 is provided in the steam connection line 10 of each steam injection module 4 .

On the opposite side in FIG. 1 of the steam supply line 7 , connecting lines of a cleaning system are connected to the steam injection modules 4 , which have a cleaning agent supply line 12 and an adjoining transverse connection to which the individual steam injection modules 4 each have a cleaning agent connecting line 13 are connected. In the detergent supply line 12 , a shut-off valve 14 is provided, while all cleaning agent-to connection lines 13 are equipped with a shut-off valve 15 . Each detergent connection line 13 is in flow connection via the assigned steam injection module 4 with the steam connection line 10 assigned to this module. However, the cleaning agent supply mainly takes place via a cleaning agent connection 16 provided in the steam supply line 7 , to which a separate shut-off valve 17 is assigned.

The plant shown in Fig. 2 differs from that only in that two injector regions are shown in FIG. 1 is substantially I and II provided, of which the first three Dampfinjek tion module 4 and the second two steam injection modules 4 to handled. Each injector area I, II has its own steam supply line 7 , each with a cleaning agent connection 16 . An additional feed pump 18 is connected between the two injector areas I, II.

FIGS. 3, 5 and 6 show the configuration of a steam injection module 4. This has a transverse to the product conveying direction 19 and thus radially through the free conveying cross section of the product line 2 steam pipe 20 , which in the systems shown in FIGS. 1 and 2 with its upper in FIGS. 3, 5 and 6 or . in FIGS. 1 and 2, the left end to the steam connection to parent pipe 10 and with its lower or right-hand end to the associated detergent line 13 is connected. The steam pipe 20 is provided in the area of the product line cross section with steam outlet bores 21 and is made of plastic. Furthermore, each steam injection module 4 has a plastic line 22 , which is welded to the cross-penetrating steam pipe 20 and thereby forms a one-piece plastic part with this, which is inserted into a stainless steel support 23 .

To produce the steam injection module 4 , the pro duct line section 22 is first inserted into the stainless steel support 23 and flanged at both ends. After creating the required radial bore, the steam pipe 20 , which is already provided with the steam outlet bores 21 , is assembled, which is welded to the product line 22 after the flanging of its two ends. The steam connection line 10 and the detergent connection line 13 are screwed onto the end of the steam pipe 20 that is to be arranged. The individual steam injection modules 4 are connected via threaded rods, not shown, for which through openings 24 are provided in the stainless steel support 23 .

In order to achieve a further tearing open of the product stream, a static mixing tool 25 can be connected in the mixing section 5 downstream of each steam injection module 4 , which can be designed as a plastic disk provided with product passage openings 26 according to FIG. 4.

To carry out the heating process in the systems of FIGS. 1 and 2, the shut-off valves 14, 15 and 17 joined ge and the check valves 8, 11 opens ge for the steam supply. The steam then flows through the steam supply line 7 and the steam connection lines 10 into the steam pipes 20 of the steam injection modules 4 and there through the respective steam pipe 20 , from there through the steam outlet bores 21 directly into the through the feed pump 3 in the conveying direction 19 through the respective product line section 22 penetrate the product flow promoted.

The system can be cleaned in the following steps:

• - To clean the product line 2 with its product line sections 22 , a cleaning medium can be fed directly behind the feed pump 3 into the product line 2 . The cleaning medium then flows in the system of FIG. 1 from A to B. Here, all shut-off valves 8 , 11 , 14 , 15 and 17 can be closed.
• - To clean the steam feed lines 7 , 10 and the steam pipes 20 , the shut-off valve 8 is closed, but the shut-off valves 11 , 14 , 15 and 17 are opened. The detergent fed via the cleaning agent connection 16 then flows in the illustration according to FIG. 1 from C to D. If the steam pipes 20 are flushed through this circuit, the shut-off valves 14 , 15 are closed, so that the cleaning agent is now in through the steam outlet bores 21 the product line sections 22 , that is to say from C to B in FIG. 1, flows. These cleaning circuits can be carried out alternately with the first cleaning circuit.
• - If necessary, with the shut-off valves 11 closed and the shut-off valves 14 , 15 open, detergent can also be fed into the detergent supply line 12 , in order then to flow from D to B in FIG. 1.

Claims (19)

1. A process for pasteurizing / sterilizing liquid to highly viscous, pumpable, continuously vorgeförder th products by direct steam injection to temperatures up to 150 ° C, characterized in that the product on its conveyor line successively through several spaced apart, each individually to a steam supply closable and between each mixing section forming steam injection modules is pumped, where in the product flow in each steam injection module is divided into its cross-section and in the separating plane thus formed, steam jets are applied to each steam injection module connected to the steam supply. 2. The method according to claim 1, characterized in that the called separation plane of a subsequent steam injection mo duls compared to that of the previous steam injection module rotated by a few degrees in relation to the conveying direction becomes.   3. The method according to claim 1 or 2, characterized in that for the product conveyor line materials with low Friction coefficients are used. 4. The method according to claim 1, 2 or 3, characterized net that in the product water vapor in drinking water quality is injected, the heating of the product by Condensation of the steam takes place. 5. The method according to any one of the preceding claims, characterized characterized in that a Reini for cleaning the system medium through the product conveyor and / or Steam supply lines is directed. 6. Device for pasteurizing / sterilizing liquid to highly viscous, pumpable, continuously vorgeförder th products by direct steam injection to temperatures up to 150 ° C, in particular for performing the method according to any one of the preceding claims, characterized by the following features:

• a) a product line ( 2 ), in which at least one feed pump ( 3 ) is connected to promote the product;
• b) the product line ( 2 ) is guided through a plurality of steam injection modules ( 4 ) which are spaced apart and each form a mixing section section ( 5 );
• c) each steam injection module ( 4 ) has at least one steam pipe ( 20 ) which is guided transversely to the product conveying direction ( 19 ) and thus radially through the free conveying cross section of the product line ( 2 ) and which can be connected to a steam supply line ( 7 ) Product line cross section is provided with steam outlet bores.

7. The device according to claim 6, characterized in that the steam pipe ( 20 ) of a subsequent Dampfinjektionsmo module ( 4 ) relative to that of the previous steam injection module ( 4 ) is rotated by a few degrees around the product line axis. 8. The device according to claim 6 or 7, characterized in that at least the inner lateral surface of the product line ( 2 ) has a low coefficient of friction based on the product to be conveyed. 9. The device according to claim 8, characterized in that the product line ( 2 ) consists of plastic, preferably PTFE or PFA. 10. Device according to one of claims 6 to 9, characterized in that each steam injection module ( 4 ) has a plastic product line section ( 22 ) which is welded to the transverse, also made of plastic steam pipe ( 20 ). 11. The device according to claim 10, characterized in that each steam injection module ( 4 ) has a one-piece, the pro duct line section ( 22 ) and the steam pipe ( 20 ) comprising plastic part which is inserted into a stainless steel carrier ( 23 ). 12. The device according to one of claims 6 to 11, characterized in that the steam injection modules ( 4 ) are connected in parallel with the steam supply line ( 7 ). 13. The apparatus according to claim 12, characterized in that each steam injection module ( 4 ) is assigned at least one steam shut-off valve ( 11 ). 14. Device according to one of claims 6 to 13, characterized in that at least two injector areas (I, II) are connected in series, each having a plurality of steam injection modules ( 4 ) and their own steam supply line ( 7 ). 15. The apparatus according to claim 14, characterized in that an additional För derpump ( 18 ) is connected between the injector areas (I, II). 16. The device according to one of claims 6 to 15, characterized in that the steam supply line ( 7 ) has a connection ( 16 ) for feeding a cleaning medium. 17. Device according to one of claims 6 to 16, characterized in that a hot holding section (6) adjoins the last steam injection module (4). 18. Device according to one of claims 6 to 17, characterized in that a steam into is arranged jektionsmoduls (4) or between two Dampfinjektionsmodu len (4) a static mixing tool (25) behind the steam pipe (20). 19. The apparatus according to claim 18, characterized in that the static mixing tool ( 25 ) is provided as a plastic disk provided with product openings ( 26 ) through openings.