DEVICE AND METHOD FOR STEAM DISINFECTION OF PRODUCTS

Abstract

A device for steam disinfecting products includes a treatment chamber. An evaporation pan is arranged in the chamber and heated. A liquid contained in the pan evaporates. A drying air flow is generated by a fan unit and directed onto the evaporation pan via a fan duct. A non-return element is arranged in the fan duct and prevents liquid vapor from getting from the evaporation pan to the fan unit. During an evaporation process, the fan unit is switched off and the fan duct is blocked by a non-return element. During a subsequent drying process, the fan unit is switched on and the non-return element of the fan duct is opened for the drying air flow. During operation of the fan unit, the evaporation pan is heated to a temperature above the specified minimum temperature using a heating device.

Claims

1.-14. (canceled)

15. A device (1) for steam disinfecting products, comprising: a treatment chamber (7); an evaporation pan (3) arranged within the treatment chamber (7) suitable to be filled with a liquid to be evaporated; a heating device (4) for heating the evaporation pan (3) and evaporating a liquid located therein; a fan unit (8) for generating a drying air flow; a fan duct (12) for directing the drying air flow onto the evaporation pan (3) in the treatment chamber (7), the fan duct being connected to the fan unit (8); an orifice opening (13) of the fan duct (12) arranged in the treatment chamber (7) for the outflowing drying air flow; and a non-return element (15) arranged in the fan duct (12) to prevent vapor generated by the evaporation pan (3) from traveling from the evaporation pan (3) to the fan unit (8).

16. The device (1) according to claim 15, wherein the non-return element (15) has a blocking flap (16) which is displaceably arranged within the fan duct (12) and which, in an open position, permits the drying air flow generated by the fan unit (8) to flow into the treatment chamber (7), and which, in a closed position, blocks the fan duct (12).

17. The device (1) according to claim 16, wherein the blocking flap (16) is pivotably arranged and can be pivoted into the closed position independently or by spring force actuation.

18. The device (1) according to claim 16, wherein the blocking flap (16) can be displaced into the closed position using an automatable actuation unit.

19. The device (1) according to claim 15, further comprising a temperature measuring unit for measuring a temperature of the evaporation pan (3).

20. The device (1) according to claim 15, further comprising a first bimetal switch (21) connected in a heat-conducting manner to the evaporation pan (3), wherein the first bimetal switch (21) interrupts an operation of the heating device (4) of the evaporation pan (3) as soon as a temperature of the evaporation pan (3) rises above a specified maximum value.

21. The device (1) according to claim 20, further comprising a second bimetal switch (22) which redundantly to the first bimetal switch (21) is connected in a heat-conducting manner to the evaporation pan (3).

22. The device (1) according to claim 15, further comprising a control unit (19) for controlling the heating device (4) and the fan unit (8).

23. The device (1) according to claim 22, wherein the control unit (19) comprises an evaluation unit (20) for evaluating a measurement signal of a sensor unit (25) and for activating the fan unit (8) when an evaporation process has come to an end.

24. A method for steam disinfecting products in a treatment chamber (7), comprising: exposing, over a treatment period, the products in the treatment chamber (7) to a vapor of a heated liquid which is generated in an evaporation pan (3) that is heated using a heating device (4); drying the products using a drying air flow which is introduced via a fan duct (12) into the treatment chamber (7) by a fan unit (8); switching off the fan unit (8) and blocking the fan duct (12) by a non-return element (15) during the treatment period; switching on the fan unit (8) and causing the non-return element (15) to open the fan duct (12) for a drying air flow after the treatment period has elapsed; and heating, during operation of the fan unit (8), the evaporation pan (3) to above a specified minimum temperature using the heating device (4).

25. The method according to claim 24, wherein the drying air flow is directed out of an orifice opening (13) of the fan duct (12) in the direction of the evaporation pan (3) and is then distributed in the treatment chamber (7).

26. The method according to claim 24, further comprising measuring a specified maximum value of the temperature of the evaporation pan (3) with a sensor unit (25) and thereby determining an end of the treatment period.

27. The method according to claim 24, further comprising switching off the fan unit (8) and the heating device (4) after a specifiable drying period has elapsed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Below, an exemplary embodiment of the inventive concept is described in more detail by way of example and is shown in the drawing.

[0034] FIG. 1 is a sectional view of a device for steam disinfecting products;

[0035] FIG. 2 is a flow chart for a schematically illustrated method sequence of a method for steam disinfecting products,

[0036] FIG. 3 a temperature curve over time of an evaporation pan, heated using a heating device, of the device shown in FIG. 1, and

[0037] FIG. 4 a temperature curve over time of air in a treatment chamber of the device shown in FIG. 1, the air first being enriched with a heated liquid vapor and then a drying air flow being applied to the air.

DETAILED DESCRIPTION

[0038] A device 1 schematically shown in FIG. 1 for steam disinfecting products, not shown in FIG. 1, has a housing 2, in which an evaporation pan 3 is arranged. The evaporation pan 3 is connected in a heat-conducting manner to a heating device 4 arranged below the evaporation pan 3. The heating device 4 can be used to heat the evaporation pan 3. The heating device 4 is designed and can be operated such that the evaporation pan 3 can be heated to a temperature of more than 140 degrees Celsius. A liquid can be filled in the evaporation pan 3, which liquid is gradually evaporated during the heating of the evaporation pan 3 by the heating device 4 and thus 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, said opening unblocking the evaporation pan, and above the evaporation pan 3 forms a treatment chamber 7 largely closed by the housing cover 5. The products to be disinfected can be arranged in this treatment chamber 7.

[0039] Laterally next to the evaporation pan 3 in the housing 2, a fan unit 8 having a merely schematically indicated fan 9 is arranged. During an operation of the fan unit 8, an air flow is suctioned through a suction region 10 of the housing, which suction region is located in the base region of the housing 2. As a result, it is possible to avoid, for example during a filling process of the evaporation pan 3 with an amount of liquid, liquid being accidentally spilled over a suction region and penetrating into the fan unit 8. The ambient air suctioned through the suction region 10 in the base of the housing 2 is then guided through a suction filter 11. The suction filter 11 can be, for example, a particle filter or a suspended matter filter with which viruses and bacteria can also optionally be filtered out of the drying air flow suctioned in from outside the housing 2. The suction filter 11 is supported in an exchangeable manner in the housing 2, and therefore the suction filter 11 can be exchanged when needed.

[0040] The drying air flow suctioned in and thereby generated by the fan unit 8 is then blown laterally into the treatment chamber 7 through a fan duct 12. To this end, an opening of the fan duct 12 opens directly into the evaporation pan 3, the fan duct projecting into the treatment chamber 7 above the evaporation pan 3. As a result of the course of the fan duct 12 in the region of the orifice opening, the drying air flow generated using the fan unit 8 is directed onto the evaporation pan 3 and after exiting the orifice opening 13 flows along a surface 14 of the evaporation pan 3 and can thereby heat up.

[0041] In the fan duct 12, a merely schematically indicated non-return element 15 is arranged which has a blocking flap 16 which is mounted in a pivoting manner in the fan duct 12. In a closed position, the blocking flap 16 closes the fan duct 12 and prevents a liquid vapor generated by an evaporation of liquid in the evaporation pan 3 from being able to get into the fan duct 12 and reaching the fan unit 8.

[0042] The blocking flap 16 can be actuated with the aid of a magnetic switch 17 and can be displaced from a closed position to an open position or back. In an open position, the blocking flap 16 unblocks the fan duct 12 and therefore the drying air flow generated using the fan unit 8 can be blown through the fan duct 12 onto the evaporation pan 3 and introduced into the treatment chamber 7. The housing cover 5 has venting slots 18 out of which the air in the treatment chamber 7 can flow during an operation of the device 1 so that a pressure equalization between the treatment chamber 7 and the ambient air is possible.

[0043] The device 1 has a control unit 19 and an evaluation unit 20 connected thereto in a signal-transmitting manner. The control unit 19 can be used to control the operation of the fan unit 8 and the operation of the heating device 4. The control unit 19 can also be used to control and actuate the magnetic switch 19 for actuating the non-return element 15. Furthermore, a first bimetal switch 21 and a second bimetal switch 22 are connected to the control unit 19, which bimetal switches are arranged in series with the heating device 4 in an electric 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 fixed in a heat-conducting manner to an outer face 23 of the evaporation pan 3 facing away from the treatment chamber 7. The first bimetal switch 21 and the second bimetal switch 22 are dimensioned such that both bimetal switches 21, 22 transition from a first switching state to a second switching state when the outer side 23 of the evaporation pan 3 is heated to over 140 degrees Celsius. The arrangement of the two bimetal switches 21, 22 in series leads to a redundant switching-off of the electric circuit for the heating device as soon as the temperature of the outer side 23 of the evaporation pan 3 rises above a specified maximum temperature. When the outer side 23 of the evaporation pan 3 cools to below 80° Celsius, the two bimetal switches 21, 22 change their switching state and the electric circuit is closed again. With the aid of the evaluation unit 20, the current flow through the electric circuit of the heating device 4 or a sudden drop in the current flow when at least one of the bimetal switches 21, 22 is triggered can be identified by means of a sensor device 24. Said sudden drop in the current flow in the event of a first-time triggering of one of the two bimetal switches 21, 22 can be regarded as the end of the evaporation process and can initiate a subsequent drying process. Using an additional safety device 25, for example a fusible-wire fuse, a further monitoring of the heating device 4 can be carried out in addition to the two bimetal switches 21, 22 and an unwanted overheating of the heating device 4 or of the evaporation pan 3 can be prevented.

[0044] FIG. 2 schematically shows an example of a method sequence for a method for steam disinfecting products. The method can be carried out using the device 1 shown in FIG. 1.

[0045] In a preparatory step 26, a specified amount of a liquid must first be filled in the evaporation pan 3. The liquid can be distilled water, for example. The products to be treated are arranged in the treatment chamber 7 above the evaporation pan 3 and the treatment chamber 7 is then closed.

[0046] In a subsequent switch-on step 27, the device 1 is switched on for example by actuation of a switch, or if the device 1 is already switched on, an automated treatment process is initiated. First, a treatment of the products arranged in the treatment chamber 7 for steam disinfection is initiated.

[0047] During a treatment step 28, the heating device 4 is used to heat the evaporation pan 3 and the liquid filled therein gradually evaporates. The heated liquid vapor rises and surrounds the products arranged in the treatment chamber 7, as a result of which said products are steam disinfected. The duration of the treatment step, or the treatment period, is specified by the amount of liquid filled in the evaporation pan 3, which evaporates during the treatment step. In many cases, it is expedient for the treatment of the products with the heated liquid vapor to be carried out over a period of several minutes, for example 5 minutes. During the treatment step 28, the fan duct 12 is closed by the non-return element 15, so that no heated liquid vapor can get through the fan duct 12 and reach the fan unit 8 and suction filter 11.

[0048] During the operation of the heating device 4 during the treatment step 28, the evaporation pan 3 initially heats up comparatively quickly to a temperature value of around 100 degrees Celsius, as shown in the schematically represented temperature curve in FIG. 3. A measured temperature of the evaporation pan 3 over a time of several minutes is shown here. During the evaporation of the liquid, the temperature of the evaporation pan 3 does not rise much over 100° Celsius. As soon as the liquid has completely evaporated, however, the temperature of the evaporation pan 3 continues to rise rapidly. As soon as the temperature of the evaporation pan 3 rises to a temperature above 140 degrees Celsius, the first bimetal switch 21 and the second bimetal switch 22, which are arranged redundantly in series in the electric circuit, are triggered and thereby interrupt the electric circuit for the heating device 4. Consequently, the evaporation pan 3 gradually cools down, and therefore its temperature falls 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 pan 3 falls below a minimum temperature of around 90 degrees Celsius, the two bimetal switches 21, 22 change their switching state and close the electric circuit of the heating device 4 again, causing the heating device 4 to be switched on again and put into operation. As a result, the temperature of the evaporation pan 3 rises rapidly again. This repeated switching on and switching off of the heating device 4 can be carried out over a long period of time in order to support a drying of the products after the treatment step 28. The temperature values given in this exemplary embodiment are merely examples, and it is therefore possible to have a maximum temperature of more than or less than 140 degrees Celsius or a minimum temperature of more than or less than 90 degrees Celsius.

[0049] As a result of the first-time rise in the temperature of the evaporation pan 3 up to the maximum temperature of 140 degrees Celsius, the treatment step 28 is automatically ended and a subsequent drying step 29 initiated. In the drying step 29, the non-return element 15 is first placed into an open state, wherein the blocking flap 16 is pivoted by the magnetic switch 17 into an open position in which it unblocks the fan duct 12. Using the fan unit 8, a drying air flow is generated which is suctioned through the suction filter 11 and is blown through the fan duct 12 onto the surface 14 of the evaporation pan 3. As a result, the drying air flow, which was not previously separately heated, heats up and is then distributed within the treatment chamber 7 and dries the products located therein. A drying process of this kind can last around 20 to 30 minutes. The duration of the drying process, or of drying step 29, can be specified by means of a timer to practically any value and depending on the products to be dried and the fill state of the treatment chamber 7. During the drying step 29, the temperature of the evaporation pan 3 is held in a temperature range specified by the minimum temperature and the maximum temperature and thereby the air in the treatment chamber 7 is heated and the drying process accelerated. Because the drying air flow brushes along the surface 14 of the heated evaporation pan 3, the drying air flow, which is subsequently distributed in the treatment chamber 7, heats up. As soon as a specified time period has elapsed, the heating device 4 and the fan unit 8 are switched off in a switch-off step 30.

[0050] FIG. 4 schematically shows the time curve of a temperature of the air within the treatment chamber 7, said temperature being measured by a separate sensor. During the treatment period or during the evaporation process within the treatment step 28, the liquid filled in the evaporation pan 3 evaporates and the liquid vapor heated to around 100 degrees Celsius fills the treatment chamber 7. At the end of the evaporation process and thus at the end of the treatment step 28, the drying air flow heated by the evaporation pan 3, which continues to be heated, is distributed in the treatment chamber 7 during the subsequent drying step 29. The temperature over time of the air in the treatment chamber 7 follows the temperature over time of the evaporation plate 3 heated by the heating device 3, wherein during the drying step 27, the temperature in the treatment chamber 7 initially falls to around 45 degrees Celsius and then gradually rises to 60 degrees Celsius and more during the drying process. The drying step 29 lasts around 30 minutes.

[0051] At the specified end of the drying period, or of drying step 29, the device 1 is automatically switched off in the switch-off step 30. The steam disinfected and subsequently dried products can then be removed from the treatment chamber 7.

[0052] FIG. 5 shows merely schematically an electric circuit 31 for electrically supplying the heating device 4 of the evaporation pan 3. The electric circuit 31 is supplied, by means of an energy supply 32, not shown in more detail, of a household power grid for example with 115 V or 230 V alternating voltage. Two bimetal switches 21 and 22 connected in series with the heating device 4 are fixed to an outer side 23 of the evaporation pan 3. A safety unit 25 also connected in series constitutes an additional thermal fuse. The sensor unit 24 can be used to measure the current flow through the electric circuit 31 in a contactless manner. For this purpose, the sensor unit 24 has a magnetic coil 33, which can be used to detect the magnetic field generated by the current flow in the electric circuit 31.