Device and method for combustion analysis by means of induction furnaces and protective element for induction furnaces for the combustion analysis

1. A device for combustion analysis, comprising:

a movable sample carrier;

an induction furnace with a furnace chamber, in which carrier gas can flow during operation via at least one gas inlet to a gas outlet, and in which a sample to be analyzed can be arranged and burned in a sample container; and

a hollow protective element which in normal operation of the device, is arranged in the furnace chamber directly above the sample such that an end of the protective element facing towards the sample, together with the sample container, forms a constriction for the carrier gas flow, said constriction directing said carrier gas flow towards said sample, wherein the protective element conveys gases produced during the combustion of the sample through the protective element and to the gas outlet; and

wherein a spacing between the sample container and the hollow protective element is selectively adjustable by an up-and-down movement of the sample carrier,

wherein the hollow protective element is formed as a diffusor comprising a cylindrical portion and a conical portion, a smallest outer diameter of the conical portion being smaller than an inner diameter of an opening of the sample container, and an upward movement of the sample carrier positions the conical portion of the diffusor at the opening of the sample container.

2. The device according to claim 1 wherein the hollow protective element consists at least substantially of silicon nitride.

3. The device according to claim 1 , further comprising:

a pressure controller, wherein the pressure controller comprises a flow rate measuring device that measures a flow rate of a gas conveyed via the gas outlet, and

a pressure measuring device that measures a pressure of the carrier gas introduced into the furnace chamber; and

a control and evaluation unit coupled to the pressure controller, wherein the control and evaluation unit generates an alarm signal when the carrier gas introduced into the furnace chamber exceeds a defined maximum pressure.

4. The device according to claim 3 , further comprising:

a bypass line that bypasses the pressure controller; and

a bypass valve, wherein the pressure controller, the bypass line and the bypass valve are arranged in a line downstream of the gas outlet.

5. The device according to claim 1 , further comprising:

a ram with a scraping protrusion that is operable to automatically clean at least the hollow protective element.

6. The device according to claim 1 wherein the hollow protective element consists at least substantially of silicon nitride.

7. A device for combustion analysis, comprising:

a sample container to hold a sample to be analyzed;

an induction furnace including a furnace chamber, a sample carrier, at least one gas inlet and a gas outlet, the sample carrier having a surface to hold the sample container and moveably mounted in the furnace chamber; and

a hollow protective element which is arranged in the furnace chamber directly above the sample container such that an end of the protective element that faces the sample container, together with the sample container, forms a constriction for a carrier gas flow, the constriction which directs the carrier gas flow towards the sample in the sample container, wherein the protective element conveys gases produced during the combustion of the sample through the protective element and to the gas outlet and wherein a spacing between the sample container and the hollow protective element is selectively adjustable by movement of the sample carrier, and an upward movement of the sample carrier positions the conical portion of the diffusor at the opening of the sample container.