DE19707291C2 - autoclave - Google Patents

Description

The invention relates to an autoclave according to the preamble of claim 1.

An autoclave in the sense of the invention is a lockable chamber in which lumpy Products are exposed to treatment with flowing media. After Ab At the end of the heating and sterilization phase, the products are usually included cooled in cold water and blown off with warm air and dried.

With such sterilization autoclaves, it was already known to connect autoclaves to the To give hands where the products are on wire mesh or perforated sheets, each storage level is designed as a stacking element. Several of these at a time Stacking elements are stacked on shelves and several of these shelves are in an autoclave chamber for treatment.

The so-called Rotatherm autoclaves are located in the chamber between the pressure vessel wall and an inner sheet metal wall above the product shelves Circulation blower and heat exchanger register on the side. As process media Related to steam and air, which is sucked off above the product shelves, to the side the heat exchangers are returned down and finally from below  upwards through the product shelves. With these autoclaves one is limited to the use of air and steam as process media. The Controlling temperature and pressure is difficult to master. An even Adequate distribution of flow velocity and temperature is only incomplete come and drying processes take place largely through slow evaporation instead, since only flow velocity of can be reached below 10 m / s.

As an alternative to the Rotatherm autoclaves, there are different types of Beriese lungs autoclave. The product is heated and / or cooled here by sprinkling with water. There are designs where the water is fine perforated metal sheets are pumped, which are located above the product shelves. Of there the water rains evenly down to the upper product layer. Through the Products, the water is deflected laterally and falls down onto the one below situation with products etc. Finally the water ends up in the swamp below of the product shelf and is fed to the suction side of circulating pumps, which the Feed water back into the autoclave using a heat exchanger.

In other versions, the water is above and from several nozzles sprayed onto the products on the product shelves. With these versions succeed it is only imperfect to position the products in their various positions Sprinkle shelves evenly with water. Such a device is at known for example from EP 0 533 923 A1. There are the products in Productre galen filed, being sprayed laterally by means of water or Vapor can be sprayed. Product drying also takes place here compressed air and succeeds due to the arrangement of the products on the product shelves only imperfect.  

From DE-OS 25 40 529 an autoclave is spaced in a housing from mutually arranged support levels and with a liquid supply and discharge tion known. Interlocking carrier trays are located in the autoclave for receiving containers to be placed on them. The trays are in meh several layers are arranged one above the other. Arrange them on top of each other Carrier trays are flown through from the side and are against lifting or opening float on the carrier tray through perforated hold-down plates Expanded metal or the like are made secured. This perforated never the holding plates are suitable for lifting the load on the carrier trays prevent containers, however, cannot flow horizontally to even out the liquid flow.  

From the point of view of economy and size, it is not portable for each individual product has its own autoclave chamber with chamber door, media supply, Provide media distribution, product circulation and media removal. So stands out any previously known autoclave construction in that in an autoclave Chamber several products in one level and several of these levels on top of each other are arranged. From the point of view of quality and economy of the Be of the products in the autoclave with flowing liquids and gases on the other hand, it is ideal if the same accessories for each product in the autoclave chamber and outflow conditions of the process media with regard to throughput, temperature, Direction, speed and distribution on the product surface would be achieved. In the known autoclave, the products are in regular occupancy star placed side by side and one above the other on wire mesh or perforated panels. The advantages here are that the loading density is high and the loading and unloading processes are feasible. The disadvantage is that with sprinkling with Water only the top product level can be sprinkled evenly. The Water runs irregularly to the lower edges of the product and then falls downward. As a rule, it then only touches the edges of the ones below neten products. In case of water spotting, let the nozzles on the side the products placed further in the middle level do not have the same distribution and Spray intensity like the side products because water on products and came built-in components is reflected and together with those from previous product levels flowing water forms a kind of waterfall curtain that sprays the nozzle irregularly prevents water from passing through. A steady flow towards the Pro Products with air or steam is not known with any arrangement of Side nozzles and fans have been achieved because gas flows are very different easily as a rule after only one contact with those placed in the flow Products, get them messed up. On their way to new products then there is no sufficient pulse available to blow off. When carried out Measurements in autoclave chambers were always very uneven flow rates  from standstill to about 20 m / s maximum speed. In the previously known autoclaves, it was therefore necessary to dry the Pro products based on the gravitational drainage of water and evaporation of the unreliable and lengthy operations. A targeted blowing off of the products of adhering water drops and puddles of water in front of the end Evaporation drying has not been achieved with conventional technology.

The object of the invention is to further develop a generic autoclave the fact that the products with the process media with a relatively low construction cost can be treated equally. In addition, ho he throughputs or flow rates may be possible.

According to the invention, the object is achieved by a generic autoclave, which has the characterizing features of the main claim. Accordingly the tiers arranged one above the other for the products to be treated, each with troughs for even liquid and gas distribution these liquid openings or nozzles passing through and / or with gas nozzles assigned.

This ensures that the liquid or gas is distributed evenly on each level. These measures according to the invention thus result in a completely new flow guidance which has the following advantages, for example in the field of sterilization autoclaves:

• 1.If the autoclave is operated only for sterilization by sprinkling, i.e. without Gas nozzles, so you can egg with perfectly even sprinkling of all products ne unprecedented high packing density of the autoclave with the ent achieve speaking economic advantages.  
• 2. By sprinkling each product layer with storage floors can be so far unimportant sufficient amounts of water can be applied to each product, whereby construction costs and operating costs remain low at the same time. You would want to achieve the same spray intensity with nozzles as with happens for example in EP 0 533 923 A1, so would the packing density decrease, the construction effort increases and the operating costs of the pumps rise because of the higher pressure drops.
• 3. Due to the high sprinkling density, the heat transfer conditions between the sprinkling water and the products significantly improved. The Heating up and cooling down times are reduced as well as those for heat transfer required temperature differences between sprinkling water and product.
• 4. The following are advantageous:
  • a) a high throughput and thus low temperature differences between the entering and exiting sprinkling water,
  • b) the uniformity of the water distribution due to the storage soils, whereby there are significantly smaller individual heat treatment differences between the products.
  If, as with sterilization, a certain minimum exposure to temperature and time is stipulated, the treatment process must be less oversized in terms of temperature and exposure time in order to meet the minimum requirements. This means a gain in productivity while saving energy.
• 5. The above-mentioned equalization and shortening of treatment driving means an improvement in product quality, because the egg Properties of the products can be guaranteed in closer tolerance and The reduction in treatment time can increase overall quality impact the product.
• 6. If the autoclave is also operated with the gas nozzles, there are further advantages:
  • a) With the old systems of circulating air drying there are at least 50% longer cycle times, without the old technology being able to dry the products completely at this time.
  • b) In the old drying process, a large part of the wetness has to be removed by evaporation, whereas in the new drying process a significant part of the wetness has to be removed by blowing and pumping. The new process therefore reduces air and energy consumption in relation to a certain degree of drying.
  • c) The faster and more complete drying of the products enables several advantages of product quality, such as: B. better appearance, less moisture in the final packaging and better gas barrier properties in plastic packaging.
  • d) The further transport of dry products from the autoclave into downstream production sections avoids the "laundry room effect", i.e. wet floors, moist air and hot machines.

Preferred embodiments of the invention result from the subclaims chen.

Accordingly, the support levels can be formed by grids. The tubs can NEN be designed as perforated plate troughs, the holes through the liquid form openings. The hole sizes are dimensioned so that the liquid This accumulates in the tub and thus ensures even spraying guaranteed. The gas nozzles advantageously protrude from the plane of the pan floor so that the water can collect and not through the Gas nozzles drain off.

However, the bottom trough advantageously has comparatively larger openings or Nozzles for the passage of liquid onto the troughs arranged above it to ensure a reduction in pressure loss. Below the the bottom tub is no longer a product that should be sprinkled. Therefore, the liquid is distributed evenly over the cross-section the autoclave. The openings or nozzles can accordingly be chosen large.

If gas nozzles are provided, these are advantageous as on the tub floor existing cylinders with short inflow funnels.

The liquid openings or nozzles and / or gas nozzles are above the respective ones Troughs arranged evenly.

A liquid separator is attached below the bottom pan in the autoclave arranges the best and in a simple design best from a simple swamp can hen.  

The gas inlet arranged in the upper area of the autoclave can be used to guide baffles Have gas distribution and optionally for gas deflection.

The liquid can be supplied via at least one liquid line, where at the outlet opening of the liquid supply line, which is in the upper area of the autoclave is arranged, a distribution system is assigned, via which the liquid via the cross section of the autoclave is evenly distributed.

Possible configurations are baffle plates on which the medium is evenly removed bounces or a ring line over which the liquid medium is evenly distributed.

The process gas or the process liquid of the autoclave can be blower or a pump can be operated in a circuit, the gas nozzles advantageously being top down so moisture is still on the products sticks, can be blown off. In each case in the gas or liquid circuit a heat exchanger can be arranged.

Further details and advantages of the invention result from one in the one gene shown embodiment.

The figure shows a schematic longitudinal section through an autoclave after a Embodiment of the invention.

In the autoclave 1 , the products are arranged in layers on several superimposed floors 6 .

Each floor forms a support level for the products with an integrated flow control function for the floor below. In order to make the products accessible from all sides for the effect of the process media and to enable loading and unloading by means of grippers, the products are placed on racks 4 . These can be z. B. consist of several parallel bars or from a field with upstanding pins. These perforated sheet pans are in regular order equipped with liquid nozzles 7 and / or with gas nozzles 8 , which regulate the passage of the process media from one floor to the next floor.

The tub edges are sealed to the walls of the autoclave and to the door 2 of the autoclave or arranged with a narrow gap so that only small amounts of liquid and gas can pass through this gap without taking their way through the aforementioned nozzles.

The upper dust floor 13 and the lower dust floor 17 can be the same or similar to the other storage floors for reasons of cost. However, in particular the lower storage floor 17 preferably has larger through-bores in order to avoid unnecessary pressure losses.

The autoclave 1 is also equipped with connections 9 and 10 for supplying and removing process liquid and with connections 11 and 12 for supplying and removing process gases.

The media periphery generally includes the circulation pump P for the liquid current flow and the fan G for the gas flow.

For even distribution of the incoming process media over the stream Different cross-section can be used.

In Fig. 1, the upper storage floor 13 , an baffle plate 14 assigned to the opening of the connection 9 for liquid distribution and baffles 15 for gas distribution and deflection is shown as an example.

To separate the withdrawn process media into a low-liquid gas stream on the one hand and a low-gas liquid stream on the other hand, a liquid separator is used, which is realized as an example in FIG. 1 as a simple sump 16 .

The liquid nozzles 7 are advantageously designed as simple bores through the trough bottoms. The number and bore cross-section of the nozzles are chosen in relation to the throughput of the process liquid so that the liquid builds up a few mil limeter high in the sheet metal pan.

The accumulation of liquid above each product-equipped floor has the following advantages:

• a) The height of the pent-up liquid column above the liquid nozzles creates an inlet pressure that ensures an uninterrupted flow through all Allows nozzles.
• b) The rivers descending from the products above the storage floors liquid is initially distributed unevenly over the surface. It pours into the accumulated liquid underneath and is evenly distributed the area. The higher the liquid is accumulated in the tubs, the more The spray pattern from the liquid nozzles on the underlying products on the next floor. This has its cause in several factors. First, the force of the surface tension occurs between fluid and nozzle bore compared to the pressure force due to the Inflow height in the background, so that the tendency to drop is stripped is tested. Secondly, a sufficient inlet height allows a larger tole ranz with the horizontal alignment of the storage floors. For example, at an inlet height of 5 mm and a deviation of the storage floors of 1 mm  from the horizontal still a pressure fluctuation in the inflow of 20% ver real light, there is an inlet pressure swan at an inlet height of 20 mm only 5% between the liquid nozzles. The third enables a deeper perforated sheet pan has a larger permissible storage height range, so that it is easier to insert the appropriate flow rate through the circulation pump regulate.

The gas nozzles 8 are advantageously designed as cylinders with short inflow funnels, which protrude from the plane of the liquid nozzles. Since the gas nozzles are sealed in the bottoms of the sheet metal troughs, the liquid can distribute them around the gas nozzles largely unaffected and build up. If one chooses skillful ratios in number, bore cross section and distribution between the gas nozzles 8 and the liquid nozzles 7 , then despite the presence of the gas nozzles, a largely homogeneous spray pattern of the liquid nozzles is obtained, even if parts of the liquid pass through immediately after the products have run out the gas nozzles fall through to the next lower product level. If one also wants to exclude this effect, one can arrange a small roof at some distance above the gas nozzles, similar to the rain protection roofs over man chimneys (not shown in Fig. 1).

To optimize between the total gas throughput on the one hand and the number, shape, cross-section and distribution of the gas nozzles 8 on the other hand, several mutually influencing effects must be coordinated with one another.

• - The gas nozzles are intended to help distribute the gas flow evenly from one floor to the lower floor over all gas nozzles. Several influences are responsible for an even gas flow distribution:
  • a) The product packing density:
    Increasing the distance between the products laterally and upwards or downwards to the storage floors, the flow of the products is less disordered, so that the nozzles can be operated with less pressure loss to the gas flow again organize.
  • b) The gas throughput:
    If you increase the gas throughput, one level increases for all gas nozzles because of their throttling effect, the static pressure difference between the inflow and outflow side and thus between two levels. This static pressure component acts uniformly on all nozzles of a storage floor and leads to a correspondingly increased uniform flow component through the nozzles. On the other hand, the higher gas throughput also causes higher flow velocities at the nozzle outlets. These currents are now being slowed down, realized and distracted to a greater extent by the products to which they are subjected. In this way, a flow which is more unevenly distributed with respect to the directions and the amounts of the flow velocity arrives at the inflow sides of the gas nozzles of the storage floor located below the products. This unevenly distributed, dynamically caused component of the gas nozzle flow thus destroys part of the equalizing effect of the stronger backflow.
  • c) Number and bore cross section of the gas nozzles in relation to the floor area:
    If you reduce the number and / or the bore cross-section of the gas nozzles, you get qualitatively the same effects as when increasing the gas throughput. However, the effect of equalizing the gas throughput over the floor area predominates here. However, the local distribution of the flow velocity is now becoming more uneven.
  • d) Distribution of the gas nozzles over the floor area:
    A deliberately non-uniform gas nozzle distribution can, under certain circumstances, result in a more uniform flow distribution for the inflow sides of the nozzles underneath. With this optimization, however, you are more committed to certain product types and occupancy patterns.
    The arrangement can be changed within this range.
  • e) The gas nozzles are intended to help bring the gaseous process media into contact with the products in an optimal manner. Taking the example of "drying wet products with air", this means: If you want to remove a large part of the water mechanically, i.e. by blowing it off the product, and the rest by effective evaporation, you need flow velocities from around 16 m / s relative to the product surface. Experiments show that with certain combinations of total gas throughput, nozzle bore cross-section and nozzle spacing, the best way to bring such flow speeds, starting from the nozzles, to as many product points as possible before the flow is influenced by adjacent nozzles and other flows caused by deflection and turbulence arise, have made each other ineffective.

With the autoclave according to the invention, a treatment process can be implemented in which the following is achieved:

• a) fast heating, cooling and drying times to shorten the Wa treatment times to shorten the treatment time
• b) equal treatment of all products to increase the treatment quality and to further shorten the duration of treatment less oversizing of the treatment process.

In order to meet the requirements, the autoclave according to the invention can be used as follows:

• a) You use flowing media with the highest possible throughputs and Flow rates. As a result, the heat transfer between process medium and product improved and faster heating and cooling of the products with lower temperature differences reached between process medium and product. In the case of the product drying, e.g. B. by flowing air, the blowing behavior is verbes sert and the rate of evaporation increases because of the higher Air velocity and the generated eddies on the moist boundary layer the product surface is repeatedly torn open and transported away. Due to the latter effect, you can allow yourself to dry or replace the drying air less or but to warm them up less.
• b) The process media are preferably circulated through the car slave and only exchanges part of the process medium if necessary off, for example moist against dry air. Through the circulation  media, energy and waste costs can be saved. at Liquid media are used primarily for centrifugal media transport pen for use, for the circulation of gaseous media are advantageous Suitable for axial and radial fans as well as injectors. Leave with the latter the functions "propellant jet" and "fresh gas supply" come together bine. The pumps, blowers and equipment for media processing tion, such as heat exchangers, are both inside and can also be arranged outside the autoclave chamber (in pressure-tight Versions).

However, these measures can be optimized especially if within the autoclave is supplied with an even and effective flow of all products. This is achieved by the solution presented here.

The basic ideas and principles of action and the possible construction methods for the present invention can be described as follows:
Since the one-time contact between the process medium and the product is sufficient to largely destroy the uniform distribution and the kinetic energy of the process media, the object of the invention is to re-flow the flow of the process media after it has passed through each product level by means of devices which are arranged between the product levels. to structure.

In order to keep the space requirements and construction costs low, liquid is used for this like the principle of the storage floor. Because liquids and Gases differ greatly in density, compressibility and toughness, and there moreover, the requirements for liquid and gas flows in the car klav process are very different, the suitable storage soils fall for Liquids and gases are geometrically very different. To the ideas for the  Appropriate construction of the storage floors for liquids and for gases must therefore ideas still arise to design the storage floors so that they are suitable for liquids and Ga se work in parallel and without mutual interference.

The storage floors have common for use for liquids and gases Properties on. Both types of stalls work passively, i. H. it won't Energy supplied from outside. Instead, potential energies that the Process media are fed before entering the chamber, step by step by produk level to the product level, in the required targeted and specifically distributed kineti energy converted.

The liquid storage floors are characterized by their trough shape, i. H. thereby, that the liquid enter the tub from above and collect there on the Distribute area and can build up to a desired drop height. In the ground the tub, the liquid nozzles are incorporated in a regular arrangement which flows in the liquid under the hydrostatic filling pressure and from pours there in an even distribution over the product level below. The liquid nozzles can contain any design. In the simplest case are round holes in the bottom of a sheet metal tub. In the case of the realized the total autoclave cross-sectional area is about 1-2% of the product level area.

The gas storage floors do not need raised troughs to function edges like the liquid storage floors. Rather, the edges of the storage floor must be like this close to the walls of the autoclave chamber (corresponds to the total flow cross section) connect that a painfully small part of the gas flow around can flow around the storage floor. The storage floor therefore consists of an out Adequate flow-tight level (e.g. a sheet) with inserted gas nozzles. In front The gas builds up in the gas nozzles, i. H. it lies with its static  Overpressure, which he uses as a potential energy supply through a suitable blower stop, evenly at the entry points of all gas nozzles. When passing through through the nozzles, part of this potential energy is converted into targeted kinetic Energy converted. The individual gas flows emerge at around 18-28 m / s Nozzles and hit the surfaces of the after about 2-8 cm running distance underlying products. The design and arrangement of the gas nozzles can be freely ge be chosen. The total gas nozzle flow is in the autoclaves cross-sectional area about 10-20% of the product-level area. In the simplest case the gas storage floor is a piece of sheet metal with individual round holes. The right choice the number of gas nozzles, flow cross sections and distribution relative to the given The pressure and volume flow of the gas blower is decisive for the blow-off effect. The effect of a uniform gas distribution on the surface, however, can not be Critical and easy to achieve as with the liquid storage floors.

If a combined liquid and gas storage floor is to be realized, the procedure is as follows proceed. First you take a tub in which liquid is dammed up can and the tub edges are so close to the chamber wall that no significant part of the gas flow between the tub rim and the chamber wall can flow through. Alternatively, it is possible to have the storage floors without your own wall sufficiently liquid and gas tight against the chamber walls, e.g. B. by a welding, sealing. The liquid nozzles are attached to the storage floor that the pent-up liquid flows through them into the next product level can. The flow cross-sectional area of the liquid nozzles is in relation to Flow cross-sectional area of the gas nozzles dimensioned so small that even with feh a negligible part of the gas flow through the liquid nozzles. The gas nozzles are brought into the same storage floor so that they look like chimneys on a flat roof from the storage floor level protrude upwards. This design allows the liquid to move around the gas jam around and cannot pass through the gas nozzles. This only applies to  the liquid that has already collected in the tub. Single drops or small streams of liquid that, running from the products, just above the gas nozzles fall straight through the gas nozzles into the Pro below duktebene. Experiments with realistic arrangements of products and nozzles ha ben showed that so little of the liquid bypassing the tubs accumulation distribution through the gas nozzles occurs that in practice there is no uneven Liquidity problem arises, especially since the gas nozzles in the executed case are clearly fine res grid as the products. If you want the passage of liquid through the Prevent gas nozzles completely, so you can have a small roof over each gas nozzle arrange that the falling liquid to the sides into the liquid pan derives. The roofs must be in line with the inlet cross-sections of the gas nozzles Adequate distance to be arranged for the gas flowing in from the side there are no unnecessarily large pressure drops.

Another variant of a combined liquid-gas storage floor results as follows. You dispense with the liquid nozzles and in turn design the gas nozzles as "towering chimneys". The gas nozzle edges form for the liquid each the overflow weir and are advantageous of wedge-shaped jagged structure, for example like a crown. The even distribution of the liquid comes through the uniform distribution of the gas nozzle edges over the product level. The tub must not be allowed to drain completely after use be completely tight, which is e.g. B. through some holes in the tub floor leaves.

The invention can be used in autoclaves for steam-water sterilization of stuffy, usually use liquid-containing products. The inventor can be advantageous in most of the currently known autoclave types, such as large and Small chamber autoclaves, steam and sprinkler autoclaves, double door and Rotary autoclaves, etc. can be used to advantage.

Claims (12)

1. Autoclave with spaced apart in a housing on location levels and with a liquid inlet and outlet and a gas supply and discharge, characterized in that the tiered stacked support levels each tubs for uniform liquid and gas distribution with liquid openings passing through them or nozzles and / or associated with gas nozzles. 2. Autoclave according to claim 1, characterized in that the support levels are formed by grids.   3. Autoclave according to claim 1 or 2, characterized in that the tubs are designed as perforated sheet troughs, the holes being the liquid form passage openings. 4. Autoclave according to one of claims 1-3, characterized in that the the bottom pan has comparatively larger openings or nozzles for the rivers has passage than the tubs arranged above it. 5. Autoclave according to one of claims 1-4, characterized in that the Gas nozzles made of cylinders with short ons standing on the tub floor there are funnels. 6. Autoclave according to one of claims 1-5, characterized in that the Liquid openings or nozzles and / or gas nozzles via the respective Tubs are evenly distributed. 7. Autoclave according to one of claims 1-6, characterized in that under A liquid separator was arranged halfway down the bottom pan in the autoclave is not. 8. Autoclave according to claim 7, characterized in that the liquid ab separator consists of a swamp. 9. Autoclave according to one of claims 1-8, characterized in that the im Upper part of the autoclave arranged gas inlet guide plates for gas ver division and optionally for gas deflection. 10. Autoclave according to one of claims 1-9, characterized in that the Liquid can be supplied via at least one liquid supply line and that a baffle plate is assigned to the outlet opening of the liquid feed line, through which the liquid can be distributed over the cross section of the autoclave.   11. Autoclave according to one of claims 1-10, characterized in that the Process gas or the process liquid via a blower or a pump in the Cycle is feasible. 12. Autoclave according to claim 11, characterized in that in the gas or Liquid circuit is arranged at least one heat exchanger.