LABORATORY DEVICE

Abstract

The invention relates to a laboratory device, in particular to a magnetic stirrer, having a heating unit for heating a medium, in particular a liquid, in a container, and having a regulating unit that is configured to regulate the temperature of the medium, of the heating unit and/or of the container by controlling the heating power of the heating unit, wherein a weight determination unit is provided to determine the weight of the medium, and wherein the regulation of the temperature takes place in dependence on the weight determined.

Claims

1-10. (canceled)

11. A laboratory device, comprising a heating unit for heating a medium in a container; a regulating unit that is configured to regulate at least one of a temperature of the medium, a temperature of the heating unit and a temperature of the container by controlling a heating power of the heating unit; and a weight determination unit for determining the weight of the medium; wherein the regulation of the temperature takes place in dependence on the determined weight.

12. The laboratory device in accordance with claim 11, wherein the laboratory device is a magnetic stirrer.

13. The laboratory device in accordance with claim 11, wherein the medium is a liquid.

14. The laboratory device in accordance with claim 11, wherein the weight determination unit comprises a load cell.

15. The laboratory device in accordance with claim 11, wherein the weight determination unit is arranged between the heating unit and a device body of the laboratory device.

16. The laboratory device in accordance with claim 15, wherein the heating unit is configured as a hot plate.

17. The laboratory device in accordance with claim 11, further comprising at least one temperature probe that is integrated in the heating unit to determine the temperature of the heating unit.

18. The laboratory device in accordance with claim 11, wherein the laboratory device is configured such that the weight of the medium is determined at the start of the temperature regulation and the heating power is set in dependence on the weight determined at the start of the temperature regulation.

19. The laboratory device in accordance with claim 11, wherein the laboratory device is configured such that the weight of the medium is determined continuously and the heating power is adapted accordingly on a change of the weight.

20. The laboratory device in accordance with claim 11, wherein the regulating unit is configured such that the heating power of the heating unit is controlled such that a temperature increase of the heating unit and/or of the container per time unit and/or an absolute temperature of the heating unit and/or of the container does not exceed a respective predefined maximum permitted value.

21. A method of operating a laboratory device, the method comprising the steps of: heating a medium in a container by means of a heating unit; regulating at least one of a temperature of the medium, a temperature of the heating unit and a temperature of the container by means of a regulating unit by controlling the heating power of the heating unit; and determining a weight of the medium by means of a weight determination unit; wherein the temperature is regulated in dependence on the determined weight.

22. The method in accordance with claim 21, wherein the laboratory device comprises the heating unit, the regulating unit and the weight determination unit.

23. The method in accordance with claim 21, wherein the medium is a liquid.

24. The method in accordance with claim 21, further comprising the step of: determining at least one of the temperature of the heating unit, the temperature of the container and the temperature of the medium by means of at least one temperature probe.

25. The method in accordance with claim 24, wherein the at least one temperature probe is integrated in the heating unit, in the container and/or is immersed in the medium.

26. The method in accordance with claim 21, wherein the weight of the medium is determined at the start of the temperature regulation and the heating power is set in dependence on the weight determined at the start of the temperature regulation.

27. The method in accordance with claim 21, wherein the laboratory device is configured such that the weight of the medium is determined continuously and the heating power is adapted accordingly on a change of the weight.

28. The method in accordance with claim 21, wherein the heating power of the heating unit is controlled such that a temperature increase of the heating unit and/or of the container per time unit and/or an absolute temperature of the heating unit and/or of the container does not exceed a respective predefined maximum permitted value.

Description

[0026] The invention will be described in the following by way of example with reference to the drawing. There is shown:

[0027] FIG. 1 a schematic representation of an embodiment of a laboratory device in accordance with the invention together with a container.

[0028] It is first stated that the embodiment shown is of a purely exemplary nature. The number and the position of the temperature probes shown can in particular vary as desired.

[0029] FIG. 1 shows a magnetic stirrer having a heating function, i.e. a heating stirrer, having a device body 10 and a hot plate 12. A container 18 that is filled with a liquid 20 to be heated by means of the hot plate 12 is arranged on the hot plate 12. A magnetic stirrer, not shown, is located in the liquid 20 and is set into a rotating movement mixing the liquid 20 in a known manner by a rotating magnet, not shown, arranged in the device body 10.

[0030] A temperature probe 22 is provided to regulate the temperature of the liquid 20 and is immersed into the liquid 20 to determine the temperature of the liquid 20. The determined temperature is fed back to a regulating unit 16 that is arranged in the device body 10 and that controls the heating power of the hot plate 12. The liquid 20 can, for example, first be brought to a predefined temperature by means of the temperature regulation and can then be held at the predefined temperature.

[0031] A second temperature probe 22 is furthermore provided that is integrated in the hot plate 12. The temperature of the hot plate 12 that is reported to the regulating unit 16 can be monitored by means of the second temperature probe 22*. On an exceeding of a predefined temperature threshold value, the hot plate 12 can be switched off by the regulating unit 16 or the heating power can be correspondingly reduced to avoid an overheating and thus possible damage to the hot plate 12. It is generally also conceivable to regulate the temperature of the liquid 20 indirectly via the temperature determined by the second temperature probe 22. The first temperature probe 22 can then be dispensed with.

[0032] A weight determination unit 14 is furthermore provided that is arranged between the hot plate 12 and the device body 10 to determine the weight of the liquid 20 at the start of the temperature regulation. The weight determination unit 14 can, for example, be a load cell. The weight of the liquid 20 is forwarded to the regulating unit 16. The weight determined can then enter into the regulation of the temperature of the liquid 20. This is of advantage since more energy is required to heat a larger quantity of liquid than to heat a quantity of liquid small in relation thereto. The heating power can accordingly be selected the higher, the greater the weight of the liquid 20.

[0033] To determine the weight of the liquid 20, for example, the weight of the container 18 alone can be determined, on the one hand, and the joint weight of the container 18 and of the liquid 20 can be determined, on the other hand, and the weight of the liquid 20 can be determined from this difference. Alternatively, the weight of the container 18 can also be known to the magnetic stirrer or can be manually input into the magnetic stirrer so that a separate weight determination for the container 18 is not necessary.

[0034] The weight of the liquid 20 can be determined once at the start of the temperature regulation such as has been explained above. Alternatively, however, it is also possible to determine the weight continuously, in particular when some of the liquid has evaporated 20 or when liquid is topped up. In this case, the heating power can be correspondingly readjusted or adapted in dependence on the changing weight data.

REFERENCE NUMERAL LIST

[0035] 10 device body [0036] 12 hot plate, heating unit [0037] 14 weight determination unit [0038] 16 regulating unit [0039] 18 container [0040] 20 liquid, medium [0041] 22, 22 temperature probe