All alarm warnings given by the system control during a process are automatically saved and printed out on the process report or on a special temperature/pressure/speed recorder. This function is optional.
An additional aluminium lining which covers the regular insulation material has not been able to establish itself in day-to-day use. It is very sensitive to mechanical injury and tends to oxidize very easily. Use of niro sheetmetal has yielded better results for this indication.
An autoclave is a pressure vessel with a door in which the boiling point of water can be raised by increasing the pressure inside of the pressure vessel.
The form of the autoclave cage is adapted to the autoclave. Depending on the container shape and how neccessary it is that the product not be damaged after processing, the containers are either allowed to tumble into the cages or carefully stacked, if neccessary with spacers.
Computerized autoclave control units such as the S-Control can be delivered with an optional display which shows the operational mode in a graphic form.
Steam serves as an energy source. Not directly used steam, which has had energy extracted from it, precipitates as condensate. This condensate still has a relatively high energy potential and since it is also usually salt-free or contains very little salt, it can be re-introduced into the kettle system. The criteria which set the guidelines for the water qualities in steam kettle systems are laid down in different regulations VdT?V guidelines, guidelines according to TRD (technical rules for steam boilers) amongst others. The requirements for the food industry are as follows, due to technical and economical factors: clean steam, no sediments, no corrosion, low energy loss as well as operational safety. Under the term commercial sterility one understands the absence of all pathogenic and toxin-producing germs as well as the absence of all microorganisms which cause spoilage and the absence of all enzymes which would have a detrimental effect on the quality of a foodstuff if it were to be stored under normal conditions.
Chlorine kills germs. Because of the danger of reinfection via cooling water contaminated with bacteria, it must be treated with disinfectant. The European Union has issued mandatory guidelines detailing how chlorine is to be used. Chlorine is used in the form of chlorine gas, hypochlorite and chlorine isocyanurate. Chlorine was the most used method of disinfecting water, but due to the ensuing AOX development (absorbative organic halogens) its use is now approached with caution. In addition, chlorine raises the danger of corrosion in metal products,and is dependent on pH levels for optimal efficency, since above a pH level of it works sub-optimally.
Chlorine dioxide is used more and more often to disinfect water. It produces few absorbable halogenides and is effective over a wide pH range. It can be produced on - site by the sodium chloride hydrochloride acid method or by the sodium chloride chloric gas method.
Chlorine \ Bromine
The use of bromine has several advantages over the use of chlorine. Bromine for example, has good disinfectant properties up to a pH of about 9. The bromamines, which result out of a reaction with the nitrogen in water, has a higher germicidal efficency than the chloramines. The production of AOX (absorbable halogenides) is generally less than when chlorine is used. Bromine is produced by mixing chlorine bleach and bromide salts in the cooling water. Another, more elegant method is to add organic salts directly by means of special dissolving stations. These salts cause chlorine and bromine to precipitate out of the water.
Closure of the process vessel
In the standard model Satori Stocktec autoclaves are delivered with a bayonett closure. The optional hydraulic closure opens upward and is also suitable for use in automated systems. Both closure systems fulfill strictest safety standards. The built-in gaskets guarantee a leakproof seal.
Cold shock can occur in the packaging or in the product. Glass can break when very cold cooling water is used because the temperature difference between the glass inner and outer wall is too large. The glass shrinks disproportionately and breaks in weakened areas or areas under tension. Products filled into containers can also suffer a cold shock, as when emulsions crack for example. dft technology autoclaves ensure a controlled cooling down and prevent a cold shock from setting in.
Computer link system
Several system controls of a sterilization plant can be centrally controlled with a main control. In order to make this possible, special software is necessary which must be adapted to user-specific needs. Several types are an option.
The control system used has, of course, an important influence on the sterilization process. In addition to precisely controlling temperature and pressure, it is important to include them in the quality control management of each individual operational site.
The energy with which a product is supplied also has to be given off in a controlled manner. Almost as important as the adherence to pasteurisation temperatures and times is a controlled cooling down with a guaranteed final temperature of the products.
Stands for the decimal reduction time or destruction value. It is a value which is an indicator of the thermostability of vegetative spores as well as spores of microorganisms. The D - value represents the time in minutes after which 90% of the vegetative cells or spores of a certain microorganism are killed at a constant temperature. Using the D - value the aimed for F - value can be calculated. - D5 Concept, - D12 Concept
The effects of enzymes becomes evident in changes in smell and taste in foodstuffs. This change leads to spoilage and makes the food inedible. Changes in color and texture are caused by enzymes, especially in fruit and vegetable products.
The time necessary to reach a specific end germ value when starting with a specific germ at a specific temperature.
Full water immersion autoclave
Modern full water immersion autoclaves are equipped with a storage tank. The processing water is held heated in this tank or is returned before or with the cooling phase into the tank. The packages are submerged into the processing water during the heating and cooling down phases, and the water is constantly circulated. In this way, the largest volume of water possible is circulated to and around all containers.Through this water counterpressure is transferred hydraulically to all the packages in the process vessel. This is of advantage in the sterilization of foil or sheeting containers with an oxygen barrier layer. This layer however loses its barrier properties at high temperatures.The water with which the process vessel is filled causes flotation of the packages and thus a loading of the autoclave cages without the need for complicated supporting equipment. Use of a heat exchanger allows for heat recovery and makes use of a cooling water circulating-system possible.
Controlled regulatory value which controls rise and fall in temperature and counterpressure. It is defined in bar or °C per minute; reaching a certain value in a set period of time.
The lethal rate describes the killing effciency on organisms after a certain temperature is applied for a set amount of time.
Lining \ Casing
The pressure vessel is insulated with mineral wool and encased in stainless steel plates.
The operating-terminals are fitted to accommodate the height of European persons. For countries where people are generally small the operating-terminals will be placed on lower positions. This has to be indicated with the order.
The technical measures and intervals for the maintenance of the autoclave can be individually determined.
Spoilage or detrimental effects on food quality are a result of for example, microorganisms causing gas development in food (bombage). They can also lead to sourness and decay, also causing spoilage. Formation of toxins of certain microorganisms plays an important role in causing food to become inedible. Pathogenic agents must be surely and safely eliminated by the chosen heat treatment method.
Does direct steam injection lead to overheating? Not if the steam injection is controlled and combined with water circulation, as in the shower or spray system.
Overspray counterpressure autoclaves
Overspray counterpressure autoclaves work more efficiently than full water immersion autoclaves. The fact that less processing water is necessary makes itself noticeable in the thermodynamics and the heat calculation of a unit. Depending on whether heat is transferred in the product via convection or conduction a varying amount of heat transportation medium (processing water) must be circulated. This is why for compact products such as canned meat (mostly conductive, slow transfer of heat) steam\ air autoclaves are best with their steam/air-atomization. This method uses minimal amounts of water.For fluid products such as soups (mostly convection, fast heat transfer) steam\ air autoclaves are best with overspray counterpressure circulation of the process water. They are the method of choice and require more water.
Pasteurization is a method of heat treatment in which core temperatures of < 100°C are reached. As a rule, the core temperature reaches 80 to 95 °C. For HTST (High Temperature Short Time) processing, the heating medium can reach temperatures above 100°C, however the core temperature is under 100°C. Pasteurization does not completely eradicate all germs. Rather it kills off only the vegetative forms of microorganisms. In order to preserve a product with a long shelf life, the pH must be lowered below 4.5, or the aw value must be < 0.95 or the product must be cooled and kept below a temperature of 5°C.
Plate heat exchanger
Utilization of the optional plate heat exchanger allows for an effective separation of processing from cooling water. This not only greatly reduces the danger of re-infection, but also greatly simplifies the process control. In addition, it is possible to win heat back or reuse cooling water many times.
The mentioned autoclave systems can be equipped with a rotary device for end - over- end movement of the packages. Appropriate clamping devices fixate the cages with the containers in the rotor and are moved with the rotor around their lateral axis. The headspace in the containers moves through the product insofar as it possesses a fluid or viscous phase, and transports the available heat from the package walls into the core of the product. By adapting the rotational speed to the viscosity of the product, the speed of heat penetration can be optimised.
Rotor \ Drive
The rotor in the process vessel receives the filled autoclave cages. The manually operated or the optional pressurized air clamping device ensures that the product to be sterilized are secured in the cage during rotation. The rotor ring of the rotor, which rotates on trunion rollers, is screwed on and can be exchanged in case of wear and tear. The rotation drive, which is a standard installation, allows for rotation speeds of up to 2 to 24 rotations per minute. The brake motor fixates the rotor for loading and unloading of the autoclave cages in a horizontal position.
Saturated steam autoclave
The classic autoclave consists of a pressure container with a (rapidly closing) door which can be heated with saturated steam to temperatures of up to 100°C. A pressure in accordance with the temperature is automatically generated for physical reasons. Continual release of small amounts of steam serves to eliminate airpockets with their detrimental heat insulating effects. Heat transfer to the sterilized goods occurs via condensation. Problematic in such systems is that a counterpressure regulation, as is necessary for modern packaging, is possible only in the cooling off phase.
Sodium hydroxide is used to elevate the pH in drinking water above 9 in order to prevent corrosion. When decarbonated water is used an additional alkalisation of the kettle water is necessary, since due to the carbon splitting off, only minimal amounts of sodium hydroxide are produced.
Sodium sulfite serves to bind oxygen. It is added to de-gassed water in order to protect the soft water tank, the boiler feeding supply line as well as the boiler and to serve as a protectant for the condensation system. The use of conditioners such as oxygen-binding and neutralising amids is often not allowed or desired in the food industry.
The control logistics (intelligence) is laid out in the software of modern autoclave controls. The software is the connecting link between operator and machine, and carries out the pre-set sterilization programs. In addition, it monitors the execution of the processes.
Steam \ Air Autoclaves
Most product containers in use today require a support pressure in the warm-up phase so that they do not burst. In the steam\ air pressure autoclaves, pressurized air is used as a medium which dominates over steam pressure. Since the hot steam and the pressurized air do not mix homogenously, a ventilator is used for this purpose. Due to the high air content the proportion of steam is automatically reduced in the mix, as a result, the heat transfer via condensation is also reduced. The heated air has to be transferred in large amounts as evenly as possible over the packages. This is only possible if the autoclave cages are loaded with ample room between the containers. For special packaging in the area of animal nutrition for example, these systems are used, if necessary supplemented by a spray circulation of the condensed steam. The condensate is an aggressive medium and causes corrosion on container surfaces. It is absolutely necessary to use chemicals to neutralise and inhibit this effect. The problems associated with even heat transfer when using an air\ steam combination are minimized by an additional rotation and spraying a small amount of water\condensate over the to be sterilized goods.
Steam\spray autoclaves are the result of further developing the steam\ air autoclaves. Instead of with a ventilator, the air\steam mixture is achieved using an atomization of steam and the processing water which circulates in the system. For this purpose, spray nozzles are built into the upper and side areas of the processing container. Heat transfer takes place mostly via condensation onto the container surface, but also due to an extremely thin film of water from the water circulation.. Cooling of the containers requires less water as compared to other systems. When adequate counterpressure is used, the cooling due to evaporation can be utilised. Use of a heat exchanger allows for the cooling water out of a cooling water-system to be utilised and guarantees that the chemicals which need to be used for this process do not have to be at such a high concentration. The water which comes into contact with the containers is germ free due to the preceding sterilization process.
Sterilization is a heat treatment system in which core temperatures in a product reach 100°C and more. The core of a product is, from a thermal standpoint, the least advantageous spot in a product. As a rule, temperatures lie between 105°C to 130°C.S In order to reach this temperature, pressure must be used. Products whose pH is above 4.5 or whose aw value is > 0.95 are sterilized in order to attain the preservation status of a canned good or of canned goods under tropical conditions at a normal storage temperature.
The regulatory precision for temperature in STOCk autoclaves is +/-0.5°C.
When subjected to high temperatures, certain products can become damaged. For example, fat in oil emulsions, which can break (clot).
One speaks of the umbrella effect when large containers are stacked over one another and the top container covers that or those beneath and thus serves as an umbrella for it. As a result, the process water is warded off to the sides and only the top layer is adequately supplied with water. Better results can be achieved in such a case by using the steam spray system, which, because of the fact that it's nozzles are arranged on the side, can supply all levels of a container stack with processing water.
Water circulation and distribution
The water distribution and circulation takes place via the circulation pump and a pipe line and distribution system, which varyies according to machine type: Full water immersion counterspray autoclave (AUOTOMAT; ROTOMAT) Water is suctioned by the circulation pump in the lower part of the tank located on the rear floor from under each cage and is forced into the upper circulation line. Conical inlets above the individual cages allow for an even distribution of processing water. Overspray counterpressure autoclave (ROTOVAP; AUTOVAP) Processing water is stored in the hermetically partitioned floor area of the processing tank. A very effective circulation pump, located on the rear floor suctions the processing water off and forces it into the upper circulation line. Nozzles or spray heads are located above the single cages; these assure even spraying of the autoclave cages. Steam/spray autoclave (AUTOVAP DAS) In the hermetically sealed off floor of the processing vessel, processing water is stored. The laterally attached circulation pump suctions the processing water off and forces it into the circulation line which is located on the sides and top of the vessel and which consists of many nozzles. The autoclave cages are treated with a water and steam fog. The saturated steam is blown in underneath the cages at the height of the water level in the system.
The z-value defines the temperature in °C by which a certain temperature has to be raised or lowered if the same germ erradication (90%) is to be reached in a tenth or ten times of the indicated time.