EP3420291B1 - Furnace having vertical arrangement of the combustion chamber for dental components and heat-resistant base - Google Patents

Description

Technical field

The invention relates to a furnace in a vertical arrangement of the combustion chamber for dental components and to a heat-resistant base for heated, in particular sintered, dental components which are removed from the furnace and have residual heat.

Such ovens for dental components are often designed as table-top units and thus have a significantly smaller design than conventional industrial ovens. It is also particularly advantageous if there is no need for a separate high-voltage connection to operate the oven for dental components. This is not just a sintering process, but basically drying ovens or ovens for crystallization or glazing are also possible. Such furnaces differ among other things by the temperature ranges, so a temperature range of 1500 ° C - 1600 ° C is usually required for sintering, the crystallization of glass ceramic and the glazing, i.e. the coating of zirconium oxide with glass ceramic takes place at temperatures of 800 ° C takes place and the drying of a dental component after wet machining takes place in a temperature range of 150 ° C - 200 ° C.

State of the art

From the DE 10 2012 213 279 A1 a sintering furnace for dental components is known in which a component arranged on a carrier is removed from the combustion chamber together with the carrier after sintering and is placed on a fireproof base at room temperature. Doing so the wearer functions as a temperature buffer to compensate for possible thermal shock. In this cooling zone, the component arranged on the carrier cools from a temperature between 275 and 600 degrees to a temperature between 100 and 200 degrees Celsius, and the component is then removed from the carrier and placed on a metal base at room temperature, where the component follows is lukewarm for a maximum of 2 minutes and can be further processed.

From the DE 10 2013 226 497 is known to operate a dental furnace with a temperature profile with a phase for cooling.

From the DE 10 2006 032 655 A1 a dental technology oven is known in which a temperature-dependent position control of the closure plate is provided. The drying upstream of the firing takes place independently of the heating or cooling phase of the combustion chamber and the drying time of the firing material placed on the sealing plate before firing can be reduced.

A dental furnace with an upper part which can be pivoted about a joint is from the EP 0 775 883 A1 and from the EP 1 593 922 A1 known. Storage plates for the temporary storage of the fired goods for cooling or preheating extend to the side of a lower part.

It is known that zirconium and aluminum oxide manage with short cooling times and can even be cooled in water. Glass ceramics are damaged when cooled in water, but cooling in ambient air at room temperature is not a problem.

The object of the invention is to shorten the cooling time of a component after sintering, crystallizing, glazing or drying.

Presentation of the invention

Thanks to the inventive design of a furnace in a vertical orientation for dental components, with a combustion chamber open at the bottom, the opening of which can be closed by means of a furnace door lowered in the open position in the vertical direction, comprising a storage area for the at a distance from the opening in the combustion chamber heated component, the storage area being part of the oven and with a cooling device acting on the storage area being arranged on or in the oven, the cooling time of the component removed from the oven and arranged on the shelf can be compared to cooling of the component by pure convection at room temperature be reduced.

The storage area is arranged outside the heat radiation field of the open combustion chamber. This can be, for example, with a vertical oven below the oven door or on the oven itself. Cooling can thus take place without continued heat input via heat radiation from the combustion chamber.

A storage area as part of the oven also includes a support that can be pushed out and connected to the oven if necessary.

The storage area can advantageously have a heat-resistant storage area for the heated component and the cooling device can act on the storage area.

A material is heat-resistant if it is resistant to thermal loads. Specifically, this means that the storage during operation at the intended temperatures of the component does not undergo any lasting changes. It is particularly important that, for example, the 1000 ° C hot dental component can already be placed on the shelf after a sintering process, instead of waiting about 5 minutes for cooling to approx. 400 ° C, which speeds up the overall cooling process.

So that the dental components, in particular restorations at the contact points, do not suffer from thermal shock, it is advantageous to use a material whose temperature quickly adapts to the hot component, for example an aluminum pad. In addition, discoloration can be largely avoided when using a black anodized aluminum support plate.

The shelf can advantageously have ventilation openings by means of which a cooling air flow can be directed onto the component to be arranged on the shelf. Furthermore, the ventilation openings can be fluidically connected to a fan for providing a cooling air flow. This enables both active and passive cooling of the component on the shelf.

An air-permeable, heat-insulating insert part can advantageously be arranged between the fan and the shelf, in order to prevent the heat radiation of the component from having an effect on the fan.

Instead of an air flow or in addition to an air flow, the shelf can be cooled by means of a Peltier element which is thermally coupled directly to the shelf.

According to a further development, the furnace can have two furnace doors, one of which is brought into a cooling position after the opening of the combustion chamber, while the other furnace door closes the combustion chamber in the closed position. In this way, both the loading of the combustion chamber with the component and the cooling of the component can be carried out at least partially at the same time.

Instead of or in addition to the closed position, the oven can also be designed such that a drying position is adopted in which the oven door is at a distance from the combustion chamber and does not yet close it, so that the component arranged on the oven door is only one relative to the temperature in the combustion chamber is exposed to reduced temperature. When the drying process is complete, the oven door is moved from the drying position to the closed position, in which the combustion chamber is closed by the oven door, and the dried component is then introduced into the combustion chamber.

The furnace can advantageously have a device for automatically repositioning the heated component from the opened combustion chamber into the storage area.

The device for automatically repositioning the heated component can advantageously have a gripper arm or a robot arm.

The device for automatically repositioning the heated component can advantageously have a plunger, a slide and a collecting basket.

Another object of the invention is a heat-resistant base for a heated dental component, comprising a heat-resistant shelf arranged in a housing, the Storage has a passive or active cooling device. The passive cooling device is formed in that the shelf has ventilation openings, by means of which a cooling air flow is directed onto a component to be arranged on the shelf.

A fan can advantageously be arranged below the shelf. Alternatively or in addition, a Peltier element can be arranged below the shelf.

The storage area or the storage area can advantageously have means for temperature measurement in the storage area or the storage area or the component to be cooled, for example a temperature sensor or a thermal imaging camera.

Advantageously, comparison means and display means can be present in order to compare the temperature of the component to be cooled with a predetermined limit temperature and to display it when the limit temperature is reached. In the case of permanent thermal monitoring of the dental component by means of a thermal sensor or a thermal imaging camera during its entire cooling phase, the user can be shown or informed of the earliest possible time for touching the component for further processing in all conceivable ways after reaching a limit temperature, for example as an acoustic and / or visual signal or via a notification by email or other electronic messages.

Advantageously, the cooling device can use a control unit to deliver a cooling capacity that is dependent on the means for temperature measurement.

Advantageously, several shelves with several cooling devices can be present in one housing. Such a thing trained oven or such a base then allows the storage of several heated components for cooling.

Each shelf can advantageously be individually controllable in terms of the cooling capacity. The cooling capacity of the several cooling devices can thus be operated individually in a temperature-dependent manner via a control.

Advantageously, the cooling device acting on the storage area can be arranged at a distance from the storage area in a housing section, which the component is moved past when it is removed from the combustion chamber.

The cooling device can thus be fitted in an already existing housing section which extends, for example, between a closed position of the oven door and a loading position of the oven door. A repositioning of the component is then not necessary, since the support surface of the furnace door for the component to be sintered to be sintered also simultaneously represents the support for cooling the sintered component after the combustion chamber has been opened.

Brief description of the drawings

Fig. 1

einen unteren Teil eines Dentalofens mit geöffneter Brennkammer und einem davor angeordneten Ablagebereich;

Fig. 1A

den Ablagebereich aus Fig. 1 im Detail mit aufgelegtem Bauteil;

Fig. 2

einen Dentalofen mit geöffneter Brennkammer und einem auf der Brennkammer angeordneten Ablagebereich;

Fig. 3

eine wärmefeste Unterlage, die von einem Dentalofen unabhängig ausgebildet ist;

Fig. 4

einen Dentalofen mit geöffneter Brennkammer und einem unterhalb der geöffneten Ofentür angeordneten Ablagebereich;

Fig. 5

einen Dentalofen mit geöffneter Brennkammer und einem vor der Brennkammer angeordneten Ablagebereich mit freier Konvektion;

Fig. 6

einen Dentalofen mit geöffneter Brennkammer und einem vor der Brennkammer angeordneten Ablagebereich mit einem Peltier-Element;

Fig. 7

den Dentalofen aus Fig. 1 mit einer automatischen Umpositionierung des heißen Bauteils mittels eines Greifarms bzw. Roboterarms;

Fig. 8

den Dentalofen aus Fig. 1 mit einer automatischen Umpositionierung des heißen Bauteils mittels eines Stößels (z.B. Linearaktuator oder Druckluftrohr), einer Rutsche und einem Fangkorb;

Fig. 9

einen Dentalofen mit zwei Ofentüren und mit im Gehäuse des Ofens angebrachter Belüftung;

Fig. 10

in einem Gehäuse angeordnete mehrere Ablagen mit mehreren Kühlvorrichtungen;

Fig. 11

eine Unterlage mit einer Steuerungseinheit. Ausführungsbeispiel der Erfindung

Exemplary embodiments of the invention are shown in the drawing.

Fig. 1

a lower part of a dental furnace with an open combustion chamber and a storage area arranged in front of it;

Fig. 1A

the storage area Fig. 1 in detail with applied component;

Fig. 2

a dental furnace with an open combustion chamber and a storage area arranged on the combustion chamber;

Fig. 3

a heat-resistant pad formed independently from a dental furnace;

Fig. 4

a dental furnace with an open combustion chamber and a storage area arranged below the open furnace door;

Fig. 5

a dental furnace with an open combustion chamber and a storage area with free convection arranged in front of the combustion chamber;

Fig. 6

a dental furnace with an open combustion chamber and a storage area arranged in front of the combustion chamber with a Peltier element;

Fig. 7

the dental oven Fig. 1 with an automatic repositioning of the hot component by means of a gripper arm or robot arm;

Fig. 8

the dental oven Fig. 1 with an automatic repositioning of the hot component using a plunger (eg linear actuator or compressed air pipe), a slide and a collecting basket;

Fig. 9

a dental furnace with two furnace doors and with ventilation in the housing of the furnace;

Fig. 10

multiple shelves arranged in a housing with multiple cooling devices;

Fig. 11

a document with a control unit. Embodiment of the invention

Fig. 1 shows a lower part of a vertically oriented dental furnace 1 with a combustion chamber open at the bottom 2, the opening 2.1 of which can be closed by means of an oven door 3 lowered in the open position in the vertical direction. The lowered furnace door 3, which is in a loading position, comprises a plate-shaped wall section 4, on which a lower and an upper door block 5, 6 are provided for isolating the combustion chamber. The upper door brick 6 has on its upper side a bearing surface 7 for a component for heat treatment in the combustion chamber 2. To load the furnace, the component is placed on the support surface 7 of the furnace door in the loading position and the furnace door is moved vertically upward and closes the combustion chamber in the closed position. After the completion of the heat treatment in the closed combustion chamber 2, the furnace door is opened by lowering it downwards and after reaching the loading position, the component which still has residual heat is removed from the support surface 7 and brought into a storage area 10 which is part of the furnace 1 in one Distance to the opening 2.1 of the combustion chamber 2 is arranged, here in front of the opening 2.1 of the combustion chamber 2. However, it is also conceivable to provide the storage area 10 laterally next to the opening 2.1 of the combustion chamber.

The component 11, which is to be or has been subjected to the heat treatment in the combustion chamber 2, can be placed on this storage area 10.

How from Fig. 1A As can be seen, the storage area 10 has a heat-resistant shelf 12 on which the heated component 11 can be placed. The storage area 10 is formed as part of a housing 13 of the dental furnace 1, more precisely as part of a base plate.

In the storage area 10 there is a cooling device 14 which acts on the storage area 12 and which comprises a fan 15 fastened to the housing 13 and which has ventilation slots 16 in the tray 12 directs an air flow 17 to the component 11 removed from the combustion chamber and arranged on the tray. The storage area 10 has a gap to the base in an oven set up on a base. Cooling air can reach the underside of the shelf through this gap or can also be sucked in by the fan and cool the shelf.

An air-permeable heat-insulating insert part 18 is arranged between the fan 15 and the shelf 12 in order to prevent the heat radiation of the component 11 from having an effect on the fan 15.

Fig. 2 shows a dental oven 1 with the oven door 3 of the combustion chamber 2 open and a storage area 10 arranged on the combustion chamber 2 at a distance from the opening 2.1 of the combustion chamber 2, with a shelf 12 which is provided with ventilation slots 16 via which an air flow 17 onto the component 11 is directed.

Fig. 3 shows a heat-resistant base 21 for a heated dental component 11, which is designed independently of a dental furnace and has a heat-resistant shelf arranged in a housing 22 with an active or passive cooling device. As a passive cooling device, ventilation slots 16 are provided here, through which an air flow can reach the component 11. The air flow 17 can be amplified by a fan (not shown) in the housing 22, which leads to an active cooling device.

Fig. 4 shows a dental furnace with an open combustion chamber 2 and a storage area 10 arranged below the opened furnace door 3 at a distance from the opening 2.1 of the combustion chamber 2, shown here in partial section. In the storage area 10, the shelf 12 is arranged on which the Component 11 is located. In the shelf 12 are as already in Fig. 1 shown ventilation slots 16 are provided, through which an air flow 17 can exit the component 11. The structure can be that of the document Fig. 3 correspond.

Fig. 5 shows a dental furnace 1 with an open combustion chamber 2 and a storage area 10 with free convection arranged in front of the combustion chamber 2 at a distance from the opening 2.1 of the combustion chamber 2. For this purpose, ventilation slots 16 are again provided in the shelf 10, but without a fan having to be present. An air flow is created by natural convection of the still warm component 11.

In Fig. 6 is a dental furnace with an open combustion chamber 2 and a storage area 10 arranged in front of the combustion chamber 2 at a distance from the opening 2.1 of the combustion chamber 2, with a Peltier element 30 instead of a passive or active air flow as in the previous ones 1 to 5 .

The Peltier element 30 is thermally coupled to the shelf 12 so that its cool side interacts with the shelf 12 and cools it and that its warm side is directed downward and is cooled by the ambient air below the housing.

Also the document Fig. 3 may have a Peltier element as an active cooling device instead of a fan.

As in the other embodiments, the storage area has a gap to the support in the case of an oven set up on a support. Through this gap, cooling air can reach the underside of the shelf or can also be sucked in by the fan and cool it.

Fig. 7 shows the dental furnace Fig. 1 with an automatic repositioning of the hot component 11 ', 11 arranged on the open furnace door 3 by means of a gripping arm 41 ', 41 or a robot arm from the upper door stone 7 into the storage area 10 with an additional temperature detection via a sensor 42 for detecting the temperature in the storage area 10.

Fig. 8 shows the dental furnace Fig. 1 with an automatic repositioning of the hot component 11 ', 11 arranged on the open oven door 3 by means of a plunger 51, which can be designed, for example, as a linear actuator or as a compressed air tube, a slide 52 and a collecting basket 53 from the upper door stone 7 into the storage area 10 an additional temperature detection in the storage area by means of a sensor 42. In addition, a thermal imaging camera 54 is provided, which is aimed at the component arranged on the storage area 12 and detects a thermal image.

Fig. 9 shows a dental oven 1 with two oven doors 3, 3 ', one of which, namely the oven door 3, is moved into a cooling position after the opening 2.1 of the combustion chamber 2 has been opened, while the other oven door 3' closes the combustion chamber 2 in the closed position. A support surface 7 for the component 11 is arranged on the upper door stone 6 of the furnace door 3 which is in a loading position. A cooling device is mounted in the housing 13 and is at a distance from the support surface 7. The support surface 7 fulfills the function of a storage area here, since the component remains on the support surface 7 during cooling. The cooling takes place by means of an air flow 17, which is generated by ventilation fans 16 in the housing 13 via ventilation slots 16 and exits the housing 13 in a manner directed towards the component 11. The fan 15 can optionally be adjustable relative to the housing in order to change the location of the air outlet of the air flow 17 directed at the component 11 from the housing 13. The loading position of the oven door in this case also corresponds to the cooling position and repositioning is not necessary since the sintered layer is identical to the cooling layer. In order to improve the cooling, instead of changing the position of the fan, it can be provided to change the cooling position relative to the loading position.

When the component 11 is cooled, a temperature is recorded via a sensor 42 for measuring the temperature in the upper door stone 6 and, if appropriate, additionally also a thermal image is recorded with a thermal imager 54 installed in the housing 13.

The cooling device acting on the storage area is arranged in a housing section, on which the component 11 is moved past when it is removed from the combustion chamber 2. The cooling device is mounted in an already existing housing section. In addition, the thermal imaging camera can also be arranged in this housing section in order to record the cooling of the component or to evaluate it for the purpose of controlling the cooling device.

In a vertical furnace shown, the closed position is the upper position, the cooling position is the lower position and the cooling device is arranged in the housing between these two positions.

The alternate adjustment of the two furnace doors 3, 3 'takes place via an adjustment mechanism 61, 62 for each of the two furnace doors 3, 3'. In this case, at least in the case of an adjustment mechanism 62, a pivoting movement can be provided for the furnace door 3 in order to prevent a collision of the two furnace doors 3, 3 'when lowering out of the combustion chamber 2 and when starting up into the combustion chamber.

The storage area is always arranged outside the direct heat radiation field of the open combustion chamber 2. This can be, for example, as here in the case of a vertical oven below the oven door or on the oven itself or to the side of it.

Fig. 10 shows several shelves 71-74, 75, 76 of different sizes arranged in a housing 70, each of which interacts with a cooling device (not shown). Such a large number of shelves can be provided both in the oven and in the base. When the temperature is recorded individually for each shelf with a sensor, the cooling device can use a control unit to emit a cooling capacity that is dependent on the signal of the temperature sensor. The cooling capacity of the plurality of cooling devices can thus be operated individually in a temperature-dependent manner via a control (not shown).

Fig. 11 shows a base 80 with a temperature sensor 42 in the support 12 and with comparison means 81 in order to compare the temperature of the component 11 to be cooled arranged on the support with the temperature sensor 42 and a predetermined limit temperature. Reaching the limit temperature is indicated by display means 82.

The comparison means 81 can be part of a control unit 83 for the cooling device, which outputs a cooling output that is dependent on the signal of the means for temperature measurement 42, for example by regulating the speed of the fan 15.

Claims (24)

1. A furnace having vertical orientation for dental components (11), comprising a combustion chamber (2) which is open at the bottom and has an opening (2.1) that can be closed by means of a furnace door (3), which in the open position is lowered in the vertical direction, having a support region (10) for the heated component (11), which support region is arranged at a distance from the opening (3) in the combustion chamber (2), is part of the furnace and is arranged outside a heat radiation field of the open combustion chamber (2), characterised in that a cooling device (14) acting on the support region (10) is arranged on or in the furnace.
2. The furnace according to claim 1, characterised in that the support region (10) has a heat-resistant support (12) for the heated component (11) and that the cooling device (14) acts on the support (12).
3. The furnace according to claim 2, characterised in that the support (12) has ventilation openings (16), by means of which a cooling airflow (17) is directed onto a component (11) to be arranged on the support (12) in the support region (10).
4. The furnace according to claim 3, characterised in that the ventilation openings (16) are fluidically connected to a fan (15) for providing a cooling air flow (17).
5. The furnace according to claim 3 or 4, characterised in that an air-permeable, heat-insulating insert part (18) is arranged between the fan (15) and the support (12).
6. The furnace according to claim 2, characterised in that the support (12) is cooled by means of a Peltier element (30), which is thermally coupled directly to the support (12).
7. The furnace according to one of claims 1 to 6, characterised in that the furnace (1) has two furnace doors (3, 3'), of which one furnace door (3) is brought into a cooling position after the opening (2.1) of the combustion chamber (2) is released, while the other furnace door (3') in the closed position closes the combustion chamber (2), wherein the furnace door (3) can preferably be brought into a drying position at a distance from the closed position and from the cooling position.
8. The furnace according to one of claims 1 to 6, characterised in that it comprises a device for automatically repositioning the heated component (11) from the open combustion chamber (2) into the support region (10)
9. The furnace according to claim 8, characterised in that the device comprises a gripping arm (41, 41') or a robot arm for automatically repositioning the heated component (11).
10. The furnace according to claim 8, characterised in that the device for automatically repositioning the heated component (11) comprises a tappet (51), a slide (52) and a collecting basket (53).
11. The furnace (1) according to one of claims 1 to 10, characterised in that the support region (10) or the support (12) has means for measuring the temperature (42) in the support region (10) or of the support (12) or of the component to be cooled (11).
12. The furnace (1) according to claim 11, characterised in that comparison means (81) and display means (82) are provided to compare the temperature of the component (11) to be cooled with a predetermined limit temperature and to display same when the limit temperature is reached.
13. The furnace (1) according to claim 11 or 12, characterised in that the cooling device delivers a cooling output dependent on the signal of the means for measuring the temperature (42) by means of a control unit (83).
14. The furnace (1) according to one of claims 1 to 13, characterised in that a plurality of supports (71-74, 75, 76) having a plurality of cooling devices is provided in a housing (13; 22).
15. The furnace (1) according to claim 14, characterised in that the cooling output of each support (71-74, 75, 76) can be controlled individually.
16. The furnace (1) according to one of claims 1 or 2 or 7 or 11-13, characterised in that the cooling device acting on the support region (10) is arranged at a distance from the support region (10) in a housing section, past which the component (11) is moved when being taken out of the combustion chamber (2).
17. A heat-resistant base (21) for a heated dental component, comprising a heat-resistant support (12) arranged in a housing (22), characterised in that the support (12) comprises a passive or active cooling device, wherein the passive cooling device is formed in that the support has ventilation slots, by means of which a cooling air flow is directed onto a component to be arranged on the support.
18. The base according to claim 17, characterised in that a fan is arranged below the support.
19. The base according to one of claims 17 to 18, characterised in that a Peltier element is arranged below the support.
20. The base (22) according to one of claims 17 to 19, characterised in that the support region (10) or the support (12) has means for measuring the temperature (42) in the depositing region (10) or of the support (12) or of the component to be cooled (11).
21. The base (22) according to claim 19, characterised in that comparison means (81) and display means (82) are provided to compare the temperature of the component (11) to be cooled with a predetermined limit temperature and to display same when the limit temperature is reached.
22. The base (22) according to claim 19 or 21, characterised in that the cooling device delivers a cooling output dependent on the signal of the means for measuring the temperature (42) by means of a control unit (83).
23. The base (22) according to one of claims 17 to 22, characterised in that a plurality of supports (71-74, 75, 76) having a plurality of cooling devices is provided in a housing (13; 22).
24. The base (22) according to claim 23, characterised in that the cooling output of each support (71-74, 75, 76) can be controlled individually.

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