Laboratory Device, In particular Magnetic Stirrer

Abstract

A laboratory device includes an outer surface section. The laboratory device further includes a display apparatus that displays a respective temperature state of the outer surface section. In addition, the laboratory device utilizes at least also heat of the outer surface section for the energy supply of the display apparatus.

Claims

1. A laboratory device, in particular a magnetic stirrer (11), comprising an outer surface section, in particular a placement surface for a vessel, wherein the laboratory device (11) comprises a display apparatus (23) that is configured to display a respective temperature state of the outer surface section (17), characterized in that the laboratory device (11) is configured to utilize at least also heat of the outer surface section (17) for the energy supply of the display apparatus (23).

2. A laboratory device in accordance with claim 1, characterized in that the laboratory device (11) comprises a heating apparatus (15) that is configured to heat the outer surface section (17) to heat up the substance.

3. A laboratory device in accordance with claim 1 or claim 2, characterized in that the laboratory device (11) comprises a heat dissipation apparatus for the outer surface section (17) and is configured to utilize a temperature gradient between the outer surface section (17) and the heat dissipation apparatus for the energy supply of the display apparatus (23).

4. A laboratory device in accordance with at least one of the preceding claims, characterized in that the laboratory device (11) comprises an energy converter (29) that is configured to convert heat of the outer surface section (17) into energy usable for the energy supply of the display apparatus (23) and to supply the energy to the display apparatus (23).

5. A laboratory device in accordance with claim 3 and claim 4, characterized in that the energy converter (29) is in a thermal relationship, in particular in thermal contact, with the outer surface section (17), on the one hand, and with the heat dissipation apparatus, on the other hand.

6. A laboratory device in accordance with claim 4 or claim 5, characterized in that the energy converter (29) is configured as a thermoelectric generator, in particular in the manner of a Peltier element.

7. A laboratory device in accordance with at least one of the preceding claims, characterized in that the display apparatus (23) comprises an illumination element (25) controllable to transmit light, in particular at least one LED, with the display apparatus (23) being configured to control the illumination element (25) to transmit light having respectively different illumination characteristics for the display of different temperature states of the outer surface section (17) and/or of different heating states of a heating apparatus (15) of the laboratory device (11).

8. A laboratory device in accordance with claim 7, characterized in that the display apparatus (23) is configured to control the illumination element (25) to transmit light in accordance with a first illumination characteristic, in particular constantly illuminating light, for the display of a switched on state of the heating apparatus (15), to control the illumination element (25) to transmit light in accordance with a second illumination characteristic, in particular pulsating light, for a combined display of a switched off state of the heating device (15) and a hot state of the outer surface section (17); and/or to control the illumination element (25) to transmit light in accordance with a third illumination characteristic, in particular no light, for a combined display of a switched off state of the heating apparatus (15) and a cool state of the outer surface section (17).

9. A laboratory device in accordance with claim 7 or claim 8, characterized in that the display apparatus (23) is configured to control the illumination element (25) to transmit pulsating light of different pulse frequencies for the combined display of a switched off state of the heating apparatus (15) and of different hot states of the outer surface section (17).

10. A laboratory device in accordance with any one of the claims 7 to 9, characterized in that respective illumination characteristics for displaying different temperature states of the outer surface section (17) differ with respect to the pulse frequency, the color and/or the brightness of the respective light transmitted by the illumination element (25).

11. A laboratory device in accordance with at least one of the preceding claims, characterized in that the laboratory device (11) comprises an actuation element (21), in particular for switching and/or adjusting a heating apparatus (15) of the laboratory device (11), with the display apparatus (23) being provided at the actuation element (21), in particular being arranged encompassing the actuation element (21) or being integrated in the actuation element (21).

12. A laboratory device in accordance with at least one of the preceding claims, characterized in that the laboratory device (11) comprises a temperature sensor for detecting a respective temperature of the outer surface section (17), with the display apparatus (23) being configured to determine and display the respective temperature state of the outer surface section (17) in dependence on the respective temperature detected by means of the temperature sensor.

13. A laboratory device in accordance with at least one of the preceding claims, characterized in that the laboratory device (11) comprises a base unit (13) having at least one power supply for an optional magnetic drive and a heating apparatus (15), with the heating apparatus (15), in particular a hotplate, being formed separately from the base unit (13), and being arranged at the base unit (13), and having the outer surface section (17); and with the display apparatus (23) being provided at the base unit (13).

Description

[0055] The invention will be described in more detail in the following only by way of example with reference to the Figures.

[0056] FIG. 1 shows a possible embodiment of a magnetic stirrer in accordance with the invention in a very simplified schematic representation; and

[0057] FIG. 2 shows a possible embodiment of a magnetic stirrer in accordance with the invention in a schematic side view.

[0058] A magnetic stirrer 11 is shown in very simplified form in FIG. 1 as an example of a laboratory device having a residual heat display in accordance with the invention. The magnetic stirrer 11 comprises a base unit 13. A heating apparatus 15 is arranged at the upper side of the base unit 13. The upwardly facing front section of this shape is configured as a hotplate that can be heated. The front face of the cylindrical shape simultaneously forms a placement and heating surface 17 of the magnetic stirrer 11.

[0059] A vessel, in particular a laboratory vessel, comprising a substance to be stirred and/or to be heated can be placed on the placement surface 17 that, on a conventional arrangement of the magnetic stirrer 11 with its lower side on a planar surface such as a tabletop, is horizontally aligned. For the stirring of the substance, a magnetic stirring element, in the manner of a so-called flea, for instance, is introduced into the substance and can be driven through the lower side of the vessel to make a stirring movement.

[0060] A magnetic drive, not visible from the outside, is provided in the interior of the magnetic stirrer 11 for this purpose. It is configured to generate a magnetic field in a region adjacent to the placement surface and above the placement surface, said magnetic field then being able to exert magnetic forces on the magnetic stirring element, in particular such that the magnetic stirring element at least substantially rotates about the cylinder axis of the cylindrical shape of the heating apparatus 15. In this manner, a stirring movement of the magnetic stirring element can be induced in the middle of the substance to be stirred by the magnetic drive provided in the interior of the magnetic stirrer 11.

[0061] The heating apparatus 15 that can extend at least partly also into the interior of the magnetic stirrer 11 comprises at least one electrical heating element that thermally contacts the placement surface 17. The heating apparatus 15 can heat the placement surface 17 in this manner so that then heat can be transmitted from the placement surface 17 to the respective substance placed on the placement surface 17 to heat the substance. So that the placement surface 17 is heated as homogeneously as possible, at least said front side of the cylindrical shape of the heating apparatus 15 comprises a material having a high thermal conductivity, in particular a metal. To avoid heat from being transferred from the placement surface 17 to the base unit 13, a gap can be provided between a lower edge of the jacket surface of the cylindrical shape and the upper side of the base unit 13.

[0062] The magnetic drive and the heating apparatus 15 are supplied with power by a common power supply 27 that is integrated in the base unit and has a connector for connecting a power plug (cf. FIG. 2), with generally a separate power supply also being possible. The magnetic drive and the heating apparatus 15 are adjustable at least to the extent that they can generally be switched on and off independently of one another to selectively stir and/or heat the respective substance.

[0063] The front surface of the base unit 13 forms an operating surface 19 of the magnetic stirrer 11 at which a plurality of actuation elements 21 are arranged for the adjustment of the magnetic stirrer 11. The actuation elements 21 in particular serve to switch the magnetic drive on and off and to set a speed of change of the magnetic field to thereby set the speed of the stirring movement or to switch the heating apparatus 15 on and off and to set a heating power of the heating apparatus 15 to regulate the speed of the heating or to reach a predefined and/or set desired temperature in the hotplate and/or medium.

[0064] Only a single one of these actuation elements 21 is shown that is formed as a flat push button or as a touch element and by whose actuation the heating apparatus 15 can be alternately switched on and off. A display apparatus 23 of the magnetic stirrer 11 is provided at the push button 21 and comprises as the illumination element 25 a light permeable illumination surface that is backlit by a light source in the form of multi-color LEDs. This illumination surface surrounds the at least substantially round push button 21 in annular form. The supply of the display apparatus 23 with power can take place via the same power supply 27 that is also provided for the magnetic drive and for the heating apparatus 15. As long as the magnetic stirrer is switched on, the display apparatus 23 is fed by this power supply 27.

[0065] The display apparatus 23 is configured to light continuously with a constant brightness and color, for example red, on a switching on of the heating apparatus 15 and for the duration of the switched on state of the heating apparatus 15. A switched off state of the heating apparatus 15 can furthermore generally be indicated by the display apparatus 23 in that it is not illuminated. A distinction can at least be made in this manner with reference to the display apparatus 23 whether the switched on heating state or the switched off heating state of the heating apparatus 15 is present.

[0066] In addition, the display apparatus 23 is, however, also configured to display a respective temperature state of the placement surface at least when the heating apparatus 15 is switched off. If the heating apparatus 15 has heated the placement surface 17 and is then switched off, the placement surface 17 can have a residual heat that only gradually drops. To optionally warn of the residual het in order to avoid any painful touching of the still hot placement surface 17, the display apparatus 23 can control the illumination element 25 to transmit light with an illumination characteristic different from said constant illumination for at least as long as the placement surface 17 has an unpleasantly high temperature.

[0067] In this respect, a high residual heat, that is a respective temperature of the heatable placement surface 17 in a high temperature range, for example above 100° C., is in particular signaled by an illumination of the illumination surface of the display apparatus 23 flashing at a high frequency, for example approximately 5 Hz. A reduction of the temperature over time can further be indicated in that the flashing frequency drops correspondingly continuously or in steps. The flashing frequency can, for example, amount to 4 Hz for temperatures between 80° C. and 100° C., to 3 Hz for temperatures between 60° C. and 80° C., to 2 Hz for temperatures between 50° C. and 60° C., to 1 Hz for temperatures between 40° C. and 50° C. and to 0.5 Hz for temperatures between 30° C. and 40° C. Different comparable associations of the flashing frequencies with temperature ranges can, however, also be present.

[0068] To detect the respective temperature of the placement surface 17, the magnetic stirrer 11 has a temperature sensor in the region of the heating apparatus 15, said temperature sensor being arranged directly beneath the placement surface 17 and therefore not being visible. The display apparatus 23 can determine the presence of a respective one of a plurality of predefined temperature states of the placement surface 17 with reference to temperature signals that the temperature sensor generates and outputs in dependence on the respective temperature of the placement surface 17 and can then display this respective temperature state in accordance with an illumination characteristic associated therewith.

[0069] In addition to and in parallel with the reduction of the flashing frequency, the color of the light transmitted by the multi-color LEDs additionally changes from red over orange to yellow. Provision can furthermore generally be made that the illumination element 25 transmits green light for a predefined time period, for example for 10 s, before it is fully extinguished after falling below a specific temperature, e.g. approximately 30° C. The at least substantially complete cooling of the placement surface 17 can hereby be separately signaled.

[0070] Whether the heating apparatus 15 is actually switched on or switched off and whether, in the latter case, the placement surface 17 still has a dangerously or unpleasantly high residual heat or has already cooled so much that a user can touch it without injury can be seen directly from the magnetic stirrer 11 by means of the different illumination characteristics transmitted by the display apparatus 23.

[0071] So that a warning of a hot placement surface 17 is still also possible when the magnetic stirrer 11 is completely switched off, the display apparatus 23 is not supplied with power via the general power supply 27, bur is rather electrically connected to an energy converter 29 configured as a thermoelectric generator (cf. FIG. 2). Said energy converter 29 is suitable to at least partly convert the residual heat present at the placement surface 17 or at another part of the heating apparatus 15 after the heating up into electrical energy with which then the display apparatus 23 can be fed independently of the general power supply 27.

[0072] The two different manners of supplying the display apparatus 23 with power can be recognized in the embodiment of a magnetic stirrer 11 shown schematically in FIG. 2. This embodiment largely corresponds to the embodiment shown in FIG. 1 so that the same reference numerals are used for mutually corresponding elements.

[0073] Unlike in the embodiment of FIG. 1, in the embodiment shown in FIG. 2, the actuation element 21 is not configured as a push button or as a touch element, but rather as a rotary button. It can, for example, be used beyond the mere switching on or off for a regulation, e.g. of the strength of the heating power. The display apparatus 23 is configured as an illuminated ring surrounding the rotary button 21. The display apparatus 23 can, however, generally also be implemented as a separate display unit, for example as an LED.

[0074] In the schematic representation of FIG. 2, the power supply 27 can, on the one hand, be seen in the interior of the base unit 13 of the magnetic stirrer 11 that is configured as a power part and that can be connected to an outlet via a cable. The electrical connection between the power supply 27 and the display apparatus 23 is shown as a dashed line. On the other hand, it can be recognized in FIG. 2 that a foot section 31 of the heating apparatus 15 is inserted into the base unit 13. The residual heat present at the placement surface 17 after a heating can be substantially irradiated only either to the environment or dissipated by heat conduction via the foot section 31 from the placement surface 17. A temperature gradient is therefore formed between the placement surface 17 and a region of the foot section 31 facing away from the placement surface 17. The foot section 31 can to this extent act as a heat dissipation apparatus for the placement surface 17.

[0075] Said temperature gradient can be tapped by the only schematically shown energy converter 29 that is arranged at the foot section 31 and can be used to at least partly convert the residual heat into electrical energy. A further energy source is thus available for the display apparatus 23 that only depends on whether a sufficient residual heat is still present at the placement surface 17 that is, however, independent of the general power supply 27. The energy converter 29 is connected to the display apparatus 23 via a further electrical connection shown schematically by a dashed line.

[0076] The display apparatus 23 can also still warn of the temperature state of the placement surface 17, in particular by lamps, with a switched off power supply 27 due to such a configuration in accordance with the invention as long as said placement surface 17 still has such a residual heat that it should e.g. in particular not be touched. The independence of the display apparatus 23 from the general power supply 27 thus achieved thus provides improved security of the magnetic stirrer 11.

REFERENCE NUMERAL LIST

[0077] 11 magnetic stirrer [0078] 13 base unit [0079] 15 heating apparatus [0080] 17 placement surface [0081] 19 operating surface [0082] 21 actuation element [0083] 23 display apparatus [0084] 25 illumination element [0085] 27 power supply [0086] 29 energy converter [0087] 31 foot section