EP4149566A1

EP4149566A1 - Device and method for steam disinfection of products

Info

Publication number: EP4149566A1
Application number: EP20731816.3A
Authority: EP
Inventors: Frieder Linder; Harald Sauer; Alexander Peter Krueger; Michael Markus Heckmann
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-05-12
Filing date: 2020-06-03
Publication date: 2023-03-22
Also published as: US20230181776A1; WO2021228415A1; DE102020112782A1; CN115867325A

Abstract

The invention relates to a device (1) for steam disinfecting products, comprising a treatment chamber (7) with an evaporation pan (3) which is arranged within the treatment chamber (7) and can be filled with a liquid to be evaporated. The evaporation pan (3) can be heated by means of a heating device (4) and a liquid contained therein can be evaporated. A drying air flow can be generated by means of a fan unit (8) and is directed onto the evaporation pan (3) via a fan duct (12) connected to the fan unit (8) in the treatment chamber (7), the fan duct (12) having an outlet opening (13) located in the treatment chamber (7) for the out-flowing drying air flow. A non-return element (15) is arranged in the fan duct (12) and prevents water vapor generated by the evaporation pan (3) from getting from the evaporation pan (3) to the fan unit (8). During an evaporation process, the fan unit (8) is switched off and the fan duct (12) is blocked by means of the non-return element (15). During a subsequent drying process, the fan unit (8) is switched on and the non-return element (15) of the fan duct (12) is opened for the drying air flow. During the operation of the fan unit (8), the evaporation pan (3) is heated to a temperature above the predetermined minimum temperature using the heating device (4).

Description

Device and method for steam disinfection of products

The invention relates to a device for steam disinfection of products with a treatment chamber, with one arranged within the treatment chamber

Evaporation trough, which can be filled with a liquid to be evaporated, with a heating device with which the evaporation trough can be heated and a liquid located therein can be evaporated, and with a fan device with which a drying air flow can be generated, which is via a fan duct connected to the fan device in the treatment chamber is directed towards the evaporation trough, the blower duct having an orifice which is arranged in the treatment chamber for the outflowing drying air flow.

Such devices are used, for example, in hospitals or in medical practices for disinfecting medical devices. It is also possible to use devices of this type to disinfect complete protective clothing or individual parts thereof, such as gloves or face masks, and to sterilize them before reuse.

Devices with a large-volume treatment chamber are known from practice, which are in a cabinet-like Housing is arranged. Such devices are suitable for the steam disinfection of a large number of products. In this case, products arranged in the treatment chamber can be disinfected with hot steam under positive pressure, but also under negative pressure. However, such devices are expensive to acquire and operate.

Smaller or inexpensive devices for steam disinfection are also known from practice. For example, in EP 2763 705 B1 a device for sanitizing and drying products is described in which an evaporation trough is arranged in a treatment chamber, wherein the device can be arranged and operated on a table. Such a device only needs a connection to a house electricity network and can be set up and put into operation quickly if necessary.

EP 3409 298 A1 shows and describes a variant of a device of this type for sanitizing and drying products, in which the fan device is not arranged below the evaporation pan, but next to the evaporation pan. A drying air flow generated with the fan device is introduced into the treatment chamber above the evaporation trough and directed onto the heatable evaporation trough. During operation of this device, the evaporation trough is heated with an electrical heating device and, at the same time, an air flow is blown into the treatment chamber with the blower device. The device described in EP 3409 298 A1 can only be operated in a single operating mode, in which both the evaporation trough is heated and an air flow is fed into the treatment chamber with the fan device.

However, it has been found that the

The disinfection effect of a liquid vapor, which is generated by the evaporation of a liquid in the heated evaporation pan, is noticeably reduced by the air flow blown in at the same time, since the air flow drawn in from the ambient air is not separately heated beforehand and is therefore significantly cooler than the liquid vapor in the treatment chamber, which is thereby greatly cooled and loses its disinfecting effect.

It is therefore considered to be an object of the present invention to design a device of the type mentioned at the beginning so that reliable steam disinfection of products in the treatment chamber can be carried out with the simplest possible means, and then the quickest possible drying of the products treated during steam disinfection is carried out can be. In addition, the device should be able to operate as reliably as possible and products should be able to be effectively steam disinfected.

According to the invention, this object is achieved in that a non-return device is arranged in the fan duct with which a liquid vapor generated with the evaporation tank from entering from the evaporation pan to the fan device is prevented can be. It has been shown that it is advantageous for reliable operation of the device that the fan device is switched off during the treatment of the products with the evaporated liquid vapor and that no cool drying air flow is blown into the treatment chamber during the steam disinfection of the products. With the given structural arrangement of the blower device, which feeds the drying air flow to the treatment chamber via the blower duct, the blower duct protruding into the treatment chamber above the evaporation pan and having an orifice arranged above the evaporation pan, it cannot be avoided with the conventional devices that during the duration of the treatment of the products with the liquid vapor, part of the liquid vapor penetrates into the fan duct and in one of the

Drying air flow in the opposite direction reaches the blower device. The blower device and in particular a suction filter present in the blower device would then come into contact with the liquid vapor. A liquid condensate precipitating from the cooling liquid vapor would not only collect on the inner walls of the fan duct, but also in the fan device and in particular in the suction filter, so that a considerable amount of condensate would accumulate there over time. As a result, the functionality of the blower device can be significantly impaired. In addition, it cannot be ruled out that an already cooled liquid vapor that penetrates the blower duct and reaches the blower device and the suction filter contains germs and possibly bacteria or viruses from the products to be disinfected can then accumulate in the suction filter and in the blower device, so that when the blower device is operated during a drying process, the products previously disinfected with the heated liquid vapor are again contaminated.

In order to be able to reliably prevent the undesired penetration of the heated liquid vapor into the blower duct up to the blower device, the invention provides that a non-return device is arranged in the blower duct, with which the undesired penetration of the liquid vapor can be prevented. During operation of the blower device, during which the drying air flow is generated and is to be directed through the blower duct into the treatment chamber and onto the evaporation trough, the non-return device is in an open state in which the blower duct is largely released for the drying air flow flowing through. However, if the blower device is not in operation, or at least during the treatment period and the evaporation of liquid in the dam, the non-return device is in a closed state and reliably closes the blower duct, so that no liquid vapor can reach the blower device via the non-return device.

According to one embodiment of the inventive concept, it is provided that the non-return device has a locking flap which is arranged displaceably within the fan duct and which is generated by the fan device in an open position Allow drying air flow to flow into the treatment chamber, while the fan duct is blocked in a closed position of the locking flap. The locking flap can either be pivotable within the fan duct or it can be displaced linearly or along a predetermined trajectory, for example along a circular arc segment, into and out of the fan duct. The locking flap can optionally be actuated manually. It is also conceivable that the locking flap can be displaced between the open position and the closed position by means of an actuator device.

It is optionally provided that the locking flap is arranged to be pivotable and can be pivoted into the closed position automatically or by means of a spring force. An automatically pivotable locking flap is known from various areas of application, such as, for example, in non-return devices in exhaust systems. The locking flap is designed and arranged in such a way that the locking flap is automatically pivoted into the closed position by its own weight and thereby closes the fan duct, while the blocking flap is pivoted into the open position by the incoming drying air flow even at a slight pressure difference, thereby releasing the fan duct. If necessary, the locking flap can also be actuated via a suitable spring device, or in particular pulled into the closed position. In this way it can be achieved that the locking flap can only be pivoted into the open position when there is a pressure difference predetermined by the spring device and no undesired opening and The fan duct is released if the fan device is not in operation.

According to a particularly advantageous embodiment of the inventive concept, it is provided that the locking flap can be displaced into the closed position with an automatable actuating device. The automatable actuating device can be, for example, a magnetic switch or an electrically operated stepper motor. By using an automatable actuating device, the operation of the actuating device or the displacement of the locking flap between an open position and a closed position can be automatically specified. This also enables the steam disinfection to be carried out in a largely or completely automated manner, as well as a subsequent drying of the steam-disinfected products. Other automatable actuating devices which can be used as actuating devices for the locking flap are also known from practice.

It is also conceivable that an automatable actuating device is combined with a spring device or with an automatic return of the locking flap. For example, the locking flap can be pressed or pulled into an open open position with a spring and, with the help of a magnetic coil or a magnetic switch, can be displaced against the spring force or its own weight into the closed position that closes the fan duct. For effective steam disinfection, it is advantageous if the products, which are initially disinfected with the liquid vapor over the course of the treatment, are then sufficiently dried to prevent the disinfection effect from being caused by still moist products that are removed from the device after steam disinfection, or by liquid residues, that still adhere to the products, is impaired, or that the products then have to dry for a long time outside the treatment chamber. The duration of treatment required for reliable steam disinfection can vary for different products. In order to be able to automatically initiate a subsequent drying process for the product to be disinfected in individual cases after the desired treatment duration, it is provided according to a particularly advantageous embodiment of the inventive concept that the device has a temperature measuring device with which a temperature range of the evaporation pan can be measured. It has been shown that during a treatment process and the evaporation of liquid in the evaporation pan that is forced by the heating device, the temperature of the evaporation pan is around 100 degrees Celsius, while this temperature rises rapidly after the liquid filled into the evaporation pan has completely evaporated. This rise in temperature can be measured with the temperature measuring device and used as a trigger for a drying process following the duration of treatment with the evaporating liquid. The heating device only has to be suitable for being able to heat the evaporation pan to well over 100 degrees Celsius. This is the case with many commercially available heating devices are easily possible.

By using a temperature measuring device, it is possible to determine the desired treatment duration of the

Specify steam disinfection by filling the evaporation tray with an appropriate amount of liquid.

The treatment time then corresponds to the time required for the complete evaporation of the amount of liquid filled into the evaporation pan. As soon as the liquid has completely evaporated and the temperature of the evaporation pan heated by the heating device rises well above 100 degrees Celsius, the steam disinfection of the products can be ended and the subsequent drying process initiated by switching on the fan device and generating a drying air flow flowing into the treatment chamber.

The temperature measuring device can, for example, be a temperature-sensitive sensor with a microcontroller that evaluates the measurement signals from the temperature-sensitive sensor. The temperature measuring device can have a thermocouple and within one

Temperature range between about 0 degrees Celsius and 150 degrees Celsius enable a comparatively precise temperature measurement that is accurate to less than a few degrees Celsius.

According to one embodiment of the inventive concept, it is provided that the device has a first bimetallic switch connected to the evaporation pan in a thermally conductive manner, with which the heating device of the Evaporation pan can be interrupted as soon as a temperature of the evaporation pan rises above a predetermined maximum value. The first bimetallic switch can be arranged, for example, on an underside of the evaporation trough and triggered in that a temperature value of the evaporation trough rises above a maximum value predetermined by the design of the first bimetallic switch, at which the bimetallic switch deforms and thereby interrupts a circuit of the heating device, so that the Heating device is switched off and heating of the evaporation pan rises above the maximum value which is predetermined by the first bimetal switch. The first bimetal switch has only two different switching states, so that no complex measurement signal processing is required for the evaluation of measurement signals from the first bimetal switch. A suitable first bimetal switch is commercially available and can be deployed and used to control the heating device with little effort. The first bimetal switch can be arranged in a circuit for the heating device so that when the evaporation pan is heated above a maximum value predetermined by the first bimetal switch, the first bimetal switch changes its switching state and interrupts this circuit, so that the heating device is switched off by the first bimetal switch and the The evaporation pan cools down. As soon as the temperature of the evaporation pan falls below a minimum value also predetermined by the first bimetal switch, the first bimetallic switch deforms again and the circuit for the heating device is closed again, so that the heating device heats the evaporation pan again. The use of a first bimetal switch to interrupt the electrical circuit of the heating device has the advantage over other control options that, depending on the temperature, a mechanical interruption of the electrical circuit for the heating device takes place and thus errors can be excluded, such as those that occur, for example, when evaluating sensors with a Microcontroller circuit cannot be completely ruled out.

With a view to the highest possible operational safety and the desired exclusion of undesired overheating of the heating device or the evaporator pan heated by it, provision is made for the device to have a second bimetal switch, which is connected to the evaporation pan redundantly to the first bimetal switch in a thermally conductive manner. The second bimetal switch can have the same triggering properties as the first bimetal switch and can be arranged in series with the first bimetal switch in the circuit of the heating device, so that when the evaporator pan is heated above the specified maximum temperature value, both bimetal switches trigger and one of the two bimetal switches already after the first triggering the circuit is interrupted. The two bimetal switches thus cause redundant monitoring and avoidance of the undesired exceeding of a maximum temperature.

It can also be provided that, in addition to the two bimetal switches, a separate safety device is provided to prevent overheating. For example, a fuse wire fuse in the circuit be arranged on the heating device and interrupt the circuit if the current flow exceeds a maximum value specified by the fuse wire fuse. There are also other safety devices known and commercially available, with which a single and permanent interruption of the circuit can be effected independently of a bimetal switch, which is usually designed to be reversible.

With a view to the greatest possible automation of the operation of the device, it is optionally provided that the device has a control device with which the heating device and the fan device can be controlled. The control device preferably has an evaluation device with which a measurement signal from a sensor device can be evaluated and the fan device can be put into operation after the end of the evaporation process. In principle, the operation of the heating device and the blower device can also each be specified manually and activated, for example, by actuating the corresponding switch. However, since the treatment time of products for reliable steam disinfection should usually be several minutes and the subsequent drying of the products usually lasts several minutes and up to half an hour or longer, manual actuation of the heating device and the fan device would be necessary at intervals of a few minutes and thus an active intervention of a user become necessary, which reduces the comfort of use of such a device. With a suitably set up and operated control device, in particular in connection with the Evaluation device first of all the treatment of the products with the heated liquid vapor takes place and then an automated drying process is initiated. The duration of the treatment of the products with heated liquid vapor can be specified in a simple manner either with a separate timer or by the amount of liquid that is filled into the evaporation trough before the start of the evaporation process. The end of the evaporation process can be automatically detected with the evaluation device and the device can be switched to drying mode. For this purpose, for example, a change in the temperature of the evaporation trough that takes place after the liquid has completely evaporated with a

The temperature measuring device is monitored and the end of the evaporation process can be determined on the basis of a sharp rise in temperature, as occurs after the liquid has evaporated. It is also possible to use a suitable sensor to detect the current flow through the circuit of the heating device and to regard the first triggering of a bimetal switch, with which this circuit is interrupted and the current flow is suddenly terminated, as the end of the evaporation process. The detection of the current flow can preferably take place without contact and can be carried out, for example, with the aid of a measuring coil or a Hall sensor. A contactless or galvanically separated detection of a change in the current flow indicating the end of the evaporation process has the advantage that the evaluation device is not electrically connected to a 230 V circuit or to power electronics components for operating the device and in particular the heating device is. The duration of the drying process can in turn be specified by a manually operated timer or a corresponding electronic control.

In order to accelerate the drying process, it is advantageously provided that the

Drying air flow is additionally heated, with which the drying process is supported and accelerated. For this purpose, the evaporation pan can be heated further during the drying process and kept at a high temperature level. The drying air flow flowing through the blower duct and flowing out of the mouth opening in the direction of the evaporation pan then brushes along the heated evaporation pan, absorbs thermal energy and is heated up in the process. A separate heating device for the drying air flow generated by the fan device is therefore not required. This enables the device according to the invention to be manufactured in a particularly cost-effective manner.

The invention also relates to a method for the steam disinfection of products in a treatment chamber, wherein the products in the treatment chamber are exposed to a heated liquid vapor over a treatment period, which is generated in an evaporation pan that can be heated with a heating device, and then dried with a drying air flow which is introduced into the treatment chamber by a fan device through a fan duct. The method described in EP 3 409 298 A1, for example, requires that the blower device also be operated with the heated liquid vapor while the products are being treated and thereby a stream of drying air is blown into the treatment chamber. However, it has been shown that reliable steam disinfection can be impaired as a result, since the temperature of the heated liquid steam is considerably reduced by the drying air flow blown into the treatment chamber.

Separate heating of the drying air flow, which is generated by the blower device and blown into the treatment chamber through the blower duct, would involve considerable additional structural effort. The method described in EP 3409 298 A1 should therefore be able to be modified if possible so that the simplest and most economical steam disinfection of products and subsequent drying of the products is made possible.

According to the invention, this object is achieved in that the fan device is switched off during the treatment duration of the steam disinfection and the fan duct is blocked with a non-return device, that after the treatment period has elapsed, the fan device is switched on and the non-return device opens the fan duct for the drying air flow, and that during the Operation of the fan device, the evaporation pan is heated with the heating device above a predetermined minimum temperature. The blower device is expediently switched off while the products are being treated with the heated liquid vapor, so that no cool drying air flow is introduced into the treatment chamber and the heated liquid vapor can have a temperature of almost 100 degrees Celsius over the duration of the treatment. This brings about a particularly reliable steam disinfection of the products in the treatment chamber.

Since the fan device is switched off during the treatment period, a portion of the heated liquid vapor could penetrate the fan duct and reach the switched off fan device, as a result of which it could be impaired or contaminated by the condensate accumulating there. In order to prevent this, according to the invention, the blower duct is blocked during the treatment period with the heated liquid vapor with the help of the non-return device so that no liquid vapor can pass through the blower duct to the blower device via the non-return device.

In order to heat the drying air flow generated by the fan duct during a subsequent drying process without the need for an additional separate heating device for the drying air flow, the evaporation trough with the heating device is heated during operation of the fan device and is kept continuously above a predetermined minimum temperature. The drying air flow blown in through the fan duct heats up when it comes into contact with the heated evaporation trough, so that the temperature in the treatment chamber rises and the drying process is accelerated as a result. According to a particularly advantageous embodiment of the method according to the invention, it is provided that the drying air flow is directed from a mouth opening of the fan duct in the direction of the evaporation trough and is then distributed in the treatment chamber. By aligning the drying air flow blown into the treatment chamber to the evaporation trough, an intensive contact of the drying air flow with the heated evaporation trough is enforced and heating of the drying air flow is promoted by stroking along a surface of the evaporation trough.

With regard to an advantageous automation of the process sequence, it is optionally provided that a predetermined maximum value of the temperature of the evaporation pan is measured with a temperature measuring device and the course of the treatment duration is thereby determined. It is also conceivable that the duration of the treatment can be specified manually with a timer. Such a specification of the treatment duration can also take place in that a user, when switching on a device that is used for steam disinfection, specifies a product to be disinfected from a predetermined number of products or a product quantity that is to be used during the subsequent treatment process with the heated liquid vapor should be disinfected.

It is expediently optionally provided that the fan device and the heating device are switched off after a predefinable drying time has elapsed. The procedure can thereby be carried out and completed without a further user intervention is required. By switching off the fan device and the heating device after a predefinable drying time, energy can be saved. If individual disinfected products are not yet sufficiently dry, a new drying process can be initiated in a simple manner and an additional drying time can be specified.

In a particularly advantageous manner, it is provided that a device described above is used to carry out the method.

In the following, an exemplary embodiment of the inventive concept is explained in more detail, which is shown in the drawing. It shows:

Figure 1 is a sectional view of a device according to the invention for steam disinfection of products,

FIG. 2 shows a flow diagram for a schematically illustrated process sequence of a method according to the invention for steam disinfection of products,

FIG. 3 shows a temperature profile over time of an evaporation trough, heated by a heating device, of the device shown in FIG. 1, and FIG

FIG. 4 shows a temperature profile over time of an air initially enriched with a heated liquid vapor and then subjected to a drying air flow in a treatment chamber of the device shown in FIG. A device 1, shown schematically in FIG. 1, for steam disinfection of products not shown in FIG. 1 has a housing 2 in which an evaporation trough 3 is arranged. The evaporation pan 3 is heat transferring with a below the

Evaporation trough 3 arranged heating device 4 connected. The evaporation trough 3 can be heated with the heating device 4. The heating device 4 is designed and can accordingly be operated in such a way that the evaporation trough 3 can be heated to a temperature of more than 140 degrees Celsius. A liquid can be filled into the evaporation trough 3, which liquid gradually evaporates during the heating of the evaporation trough 3 by the heating device 4 and thereby forms a rising, heated liquid vapor. A housing cover 5 made of a transparent material can be placed on an opening 6 of the housing 2 that exposes the evaporation trough 3 and forms a treatment chamber 7 above the evaporation trough 3, which is largely closed by the housing cover 5. The products to be disinfected can be arranged in this treatment chamber 7.

A fan device 8 with a fan 9, which is only indicated schematically, is arranged in the housing 2 to the side next to the evaporation trough 3. When the blower device 8 is in operation, an air flow is sucked in through a suction area 10 of the housing 2, which is located in a bottom area of the housing 2. In this way it can be avoided, for example during a filling process of the evaporation trough 3 with an amount of liquid, inadvertently liquid via a suction area is spilled and can penetrate into the fan device 8. The ambient air sucked in through the suction area 10 in the bottom of the housing 2 is then passed through a suction filter 11. The suction filter 11 can be, for example, a particle filter or a particulate filter with which viruses and bacteria can also be filtered out of the drying air flow sucked in from outside the housing 2. The suction filter 11 is mounted exchangeably in the housing 2 so that the suction filter 11 can be exchanged if necessary.

The drying air flow which is sucked in with the blower device 8 and thus generated is then blown laterally into the treatment chamber 7 through a blower duct 12. For this purpose, the blower duct 12 protruding into the treatment chamber 7 above the evaporation trough 3 opens with an opening 13 directly at the evaporation trough 3 is directed and, after exiting the orifice 13, flows along a surface 14 of the evaporation trough 3 and can heat up in the process.

Arranged in the fan duct 12 is a backflow blocking device 15, indicated only schematically, which has a blocking flap 16 that is pivotably mounted in the fan duct 12. In a closed position, the locking flap 16 closes the fan duct 12 and prevents a liquid from evaporating in the Liquid vapor generated from the evaporation trough 3 can pass through the blower duct 12 to the blower device 8.

The locking flap 16 can be actuated with the aid of a magnetic switch 17 and shifted from a closed position to an open position or back. In an open position, the locking flap 16 releases the fan duct 12 so that the drying air flow generated by the fan device 8 can be blown through the fan duct 12 onto the evaporation trough 3 and introduced into the treatment chamber 7. The housing cover 5 has ventilation slots 18 through which the air located in the treatment chamber 7 can flow out during operation of the device 1, so that a pressure equalization between the treatment chamber 7 and the ambient air is possible.

The device 1 has a control device 19 and an evaluation device 20 connected to it in a signal-transmitting manner. The operation of the blower device 8 and the operation of the heating device 4 can be controlled with the control device 19. With the control device 19, the magnetic switch 17 for actuating the

Reverse flow blocking device 15 are controlled and operated. A first bimetal switch 21 and a second bimetal switch 22 are also connected to the control device 19 and are arranged in series with the heating device 4 in a circuit which supplies the heating device 4 with electrical energy during a heating process. The first bimetal switch 21 and the second bimetal switch 22 are each facing away from the treatment chamber 7 Outer surface 23 of the evaporation pan 3 set in a thermally conductive manner. The first bimetal switch 21 and the second bimetal switch 22 are dimensioned such that both bimetal switches 21, 22 change from a first switching state to a second switching state when the outside 23 of the evaporation pan 3 is heated above 140 degrees Celsius. The arrangement of the two bimetal switches 21, 22 in series creates a redundant shutdown of the circuit for the heating device as soon as the temperature of the outside 23 of the evaporation pan 3 rises above a predetermined maximum temperature. When the outside 23 of the evaporation pan 3 cools below 80 ° Celsius, the two bimetal switches 21, 22 change their switching state and the circuit is closed again. With the aid of the evaluation device 20, a sensor device 24 can determine the current flow through the circuit of the heating device 4 or a sudden drop in the current flow when at least one bimetal switch 21, 22 is triggered. This sudden drop in the current flow when one of the two bimetal switches 21, 22 is triggered for the first time can be viewed as the end of the evaporation process and initiate a subsequent drying process. With an additional safety device 25, for example a fusible wire fuse, in addition to the two bimetal switches 21, 22, further monitoring of the heating device 4 can take place and undesired overheating of the heating device 4 or the evaporation pan 3 can be prevented.

FIG. 2 shows, schematically, an exemplary process sequence for a process according to the invention for Steam disinfection of products shown. The method according to the invention can be carried out with the device 1 shown in FIG.

In a preparation step 26, a predetermined amount of a liquid must first be poured into the evaporation trough 3. The liquid can be, for example, distilled water. The products to be treated are arranged in the treatment chamber 7 above the evaporation trough 3 and then the treatment chamber 7 is closed.

In a subsequent switch-on step 27, the device 1 is switched on, for example, by actuating a switch, or if the device 1 is already switched on, an automated treatment process is started. In this case, a treatment of the products arranged in the treatment chamber 7 for steam disinfection is first initiated.

During a treatment step 28, the evaporation trough 3 is heated with the heating device 4 and the liquid filled therein is gradually evaporated. The heated liquid vapor rises and surrounds the products arranged in the treatment chamber 7, as a result of which these products are steam-disinfected. The duration of the treatment step, or the treatment duration, is predetermined by the amount of liquid filled into the evaporation trough 3 which evaporates during the treatment step. In many cases it is useful that the treatment of the products with the heated liquid vapor over a period of several Minutes, for example 5 minutes. During the treatment step 28, the blower duct 12 is closed by the non-return device 15, so that no heated liquid vapor can pass through the blower duct 12 to the blower device 8 and the suction filter 11.

During the operation of the heating device 4 during the treatment step 28, the evaporation trough 3 initially warms up comparatively quickly to a temperature value of approximately 100 degrees Celsius, as is shown in the temperature profile shown schematically in FIG. A measured temperature of the evaporation trough 3 is shown over a period of several minutes. The temperature of the evaporation trough 3 does not rise significantly above 100 ° Celsius during the evaporation of the liquid. As soon as the liquid has completely evaporated, on the other hand, the temperature of the evaporation trough 3 continues to rise rapidly. As soon as the temperature of the evaporation pan 3 rises to a temperature value above 140 degrees Celsius, the first bimetal switch 21 and the second bimetal switch 22, which are arranged redundantly in the circuit in series, and thereby interrupt the circuit for the heating device 4. The evaporation pan 3 then gradually cools down so that its temperature drops to a value below 100 degrees Celsius. This prevents the heating device 4 and the evaporation pan 3 from overheating. As soon as the temperature of the evaporation trough 3 drops below a minimum temperature of about 90 degrees Celsius, the two bimetal switches 21, 22 change their switching state and close the circuit of the heating device 4 again, which leads to the fact that the heating device 4 is switched on again and put into operation. The temperature of the evaporation pan 3 then rises again quickly. This repeated switching off and switching on of the heating device 4 can be carried out over a long period of time in order to support drying of the products after the treatment step 28. The temperature values specified in this exemplary embodiment are merely exemplary, so that a higher or lower maximum temperature than 140 degrees Celsius or a higher or lower minimum temperature than 90 degrees Celsius is also possible.

When the temperature of the evaporation trough 3 rises for the first time up to the maximum temperature of 140 degrees Celsius, the treatment step 28 is automatically ended and a subsequent drying step 29 is initiated. In the drying step 29, the non-return device 15 is first placed in an open state, the blocking flap 16 being pivoted by the magnetic switch 17 into an open position in which it releases the fan duct 12. With the fan device 8, a drying air flow is generated, which is sucked in through the suction filter 11 and blown through the fan duct 12 onto the surface 14 of the evaporation pan 3. As a result, the drying air flow, which was previously not separately heated, is heated, which is then distributed within the treatment chamber 7 and dries the products located therein. Such a drying process can take about 20 to 30 minutes. The duration of the drying process, or of the drying step 29, can be set almost as desired by means of a timer and depending on the products to be dried and the filling status of the Treatment chamber 7 are specified. During the drying step 29, the temperature of the evaporation trough 3 is kept in a temperature range predetermined by the minimum temperature and the maximum temperature, thereby heating the air in the treatment chamber 7 and accelerating the drying process. As the drying air flow sweeps along the surface 14 of the heated evaporation trough 3, the drying air flow is heated and is then distributed in the treatment chamber 7. As soon as a predetermined period of time has elapsed, the heating device 4 and the fan device 8 are switched off in a switch-off step 30.

In FIG. 4, the time course of a temperature of the air measured with a separate sensor within the treatment chamber 7 is shown schematically. During the treatment period or during the evaporation process within the treatment step 28, the liquid filled into the evaporation trough 3 evaporates and the liquid vapor heated to about 100 degrees Celsius fills the treatment chamber 7. After the evaporation process and accordingly after the end of the treatment step 28, during the In the subsequent drying step 29, the drying air flow, which is heated by the evaporation trough 3, which is still heated, is distributed in the treatment chamber 7.

The temperature curve of the air in the treatment chamber 7 over time follows the temperature curve over time of the evaporation plate 3 heated by the heating device 3, the temperature in the treatment chamber 7 initially falling to about 45 degrees Celsius during the drying step 27 and then gradually rises to 60 degrees Celsius and more during the drying process. The drying step 29 takes about 30 minutes. After the predetermined expiry of the drying time or the drying step 29, the device 1 is automatically switched off in the switch-off step 30. The steam-disinfected and then dried products can then be removed from the treatment chamber 7.

In Figure 5, a circuit 31 for the electrical supply of the heating device 4 of the evaporation pan 3 is shown only schematically. The circuit 31 is supplied with an energy supply 32, not shown in detail, of a household power network, for example with 115 V or 230 V alternating voltage. In series with the heating device 4, the two bimetal switches 21 and 22 are fixed on the outside 23 of the evaporation pan 3. A safety device 25, also connected in series, represents an additional thermal fuse. With the

Sensor device 24, the current flow through circuit 31 can be measured without contact. For this purpose, the sensor device 24 has a magnetic coil 33 with which the magnetic field generated by the current flow in the circuit 31 can be detected.

Claims

PA T E N TA N S P RÜ C H E

1. Device (1) for steam disinfection of products with a treatment chamber (7), with an evaporation trough (3) arranged within the treatment chamber (7), which can be filled with a liquid to be evaporated, with a heating device (4) with which the Evaporation tray

(3) can be heated and a liquid contained therein can be evaporated, and with a fan device (8), with which a drying air flow can be generated, which via a fan duct (12) connected to the fan device (8) in the treatment chamber (7) the evaporation pan (3) is directed, the fan duct

(12) an orifice (13) arranged in the treatment chamber (7) for the outflowing

Having drying air flow, characterized in that a non-return device (15) is arranged in the fan duct (12), with which a liquid vapor generated by the evaporation tank (3) can be prevented from penetrating from the evaporation pan (3) to the fan device (8) .

2. Device (1) according to claim 1, characterized in that the non-return device (15) has a locking flap (16) which is arranged displaceably within the fan duct (12) and in an open position a drying air flow generated by the fan device (8) in allows the treatment chamber (7) to flow while the fan duct (12) is blocked in a closed position. 3. Device (1) according to claim 2, characterized in that the locking flap (16) is pivotably arranged and can be pivoted into the closed position automatically or by spring force.

4. Device (1) according to claim 2, characterized in that the locking flap (16) can be displaced into the closed position with an automatable actuating device.

5. Device (1) according to one of the preceding claims, characterized in that the device (1) has a temperature measuring device with which a temperature range of the evaporation pan (3) can be measured.

6. Device (1) according to one of the preceding claims, characterized in that the device (1) has a first bimetallic switch (21) connected to the evaporation trough (3) in a thermally conductive manner, with which operation of the heating device (4) of the evaporation trough (3 ) can be interrupted as soon as the temperature of the evaporation pan (3) rises above a specified maximum value.

7. The device (1) according to claim 6, characterized in that the device (1) has a second bimetal switch (22) which is redundantly connected to the first bimetal switch (21) in a thermally conductive manner with the evaporation pan (3).

8. Device (1) according to one of the preceding claims, characterized in that the device (1) has a Has control device (19) with which the heating device (4) and the fan device (8) can be controlled.

9. The device (1) according to claim 8, characterized in that the control device (19) has an evaluation device (20) with which a measurement signal from a sensor device (25) can be evaluated and the fan device (8) can be put into operation after the end of the evaporation process .

10. A method for steam disinfection of products in a treatment chamber (7), the products in the treatment chamber (7) being exposed to a heated liquid vapor over a treatment period which is in an evaporation trough which can be heated with a heating device (4)

(3) is generated, and then dried with a drying air flow which is introduced into the treatment chamber (7) by a blower device (8) through a blower duct (12), characterized in that the blower device (8) is switched off during the treatment period and the blower duct (12) is blocked with a non-return device (15), and that after the treatment period has elapsed, the blower device (8) is switched on and the non-return device (15) opens the blower duct (12) for the drying air flow, and that during operation the fan device (8) the evaporation pan (3) is heated with the heating device (4) above a predetermined minimum temperature.

11. The method according to claim 10, characterized in that the drying air flow from an orifice (13) of the Fan duct (12) is directed in the direction of the evaporation trough (3) and then distributed in the treatment chamber (7). 12. The method according to claim 10 or claim 11, characterized in that a predetermined maximum value of the temperature of the evaporation pan (3) is measured with a sensor device (25) and the course of the treatment duration is determined as a result.

13. The method according to claim 10 or claim 11, characterized in that after a predefinable drying time, the fan device (8) and the heating device (4) are switched off.

14. The method according to any one of claims 10 to 12, characterized in that a device (1) according to one of claims 1 to 9 is used to carry out the method.