Method of regulating a high temperature gaseous phase process and use of said method

• US 6,596,340 B1
• Filed: 10/05/2001
• Issued: 07/22/2003
• Est. Priority Date: 02/10/1999
• Status: Expired due to Fees

• Current Assignee: Schunk Kohlenstofftechnik GmbH (Ludwig Schunk Stiftung E.V.)
• Original Assignee: Schunk Kohlenstofftechnik GmbH (Ludwig Schunk Stiftung E.V.)
• Inventors: Schneweis, Stefan
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US09/890,267
• Time in Patent Office: 655 Days
• Field of Search: 427/248.1, 427/8, 427/10, 427/249.2, 427/249.16
• US Class Current: 427/10
• CPC Class Codes: G05D 27/02 characterised by the use of electric means

Abstract

A method of regulating a high temperature gas phase process on the basis of a measurement curve determined by means of infrared spectroscopy, the curve having at least one spectral peak which is characteristic for the regulation of the process and which deviates from a background of the measurement curve. A straight line synthetic background is calculated directly from the measurement curve on the basis of initial and end values of the characteristic spectral peak, and the peak is integrated over the straight line, or a maximum height of the peak over the straight line, or another characteristic value of the peak relative to the straight line is utilized. The process is regulated based on measured peak and the synthetic background.

Claims

1. A method of regulating a high temperature gas phase process on the basis of a measurement curve determined by means of infrared spectroscopy, the curve having at least one spectral peak which is characteristic for the regulation of the process and which deviates from a background of the measurement curve, comprising the steps of:

calculating a straight line synthetic background directly from the measurement curve on the basis of initial and end values of each characteristic spectral peak, integrating the peak over the straight line, determining a maximum height of the peak over the straight line or utilizing another characteristic value of the peak relative to the straight line, and

regulating the process based on measured peak and the synthetic background.

2. A method according to claim 1, wherein the regulation of the process takes place by continuous establishment and evaluation of measurement curves.

3. A method according to claim 1 wherein an on-line evaluation of the peak is effected for adjustment of at least one of the process parameters pressure, temperature, speed or concentration and process gases.

4. A method according to claim 1, wherein evaluation of the measurement curve takes place without being based on a reference measurement at a temperature which corresponds to that of the process to be regulated.

5. A method according to claim 1, wherein X initial values and Y end values of a peak are used for calculation of the straight line.

6. A method according to claim 5, characterized in that 5 to 7 initial values, and 5 to 7 end values, of the peak are used as a basis for the calculation of the straight line.

7. A method according to claim 5, wherein X and Y are equal.

8. A method according to claim 1, wherein a plurality of peaks is used and each peak is based on a separate straight line.

9. A method according to claim 1, wherein the measurement curve is determined by IR radiation emitted from an element present in a reaction chamber.

10. A method according to claim 9, wherein IR radiation of the element, emitted through an exhaust channel of the reaction chamber, is measured.

11. A method according to claim 9, wherein the element is a graphite plate.

12. A method according to claim 1 for regulating a CVD process for surface coating of carbon or graphite material with SiC, wherein at least one peak characteristic for at least one compound selected from the group consisting of HCl, CH₄, CH₃SiCl₃, HSiCl₃ and SiCl₄ is used as a basis for regulating values.

13. A method according to claim 1 for regulating a waste or refuse incineration process, wherein at least one peak, which is characteristic of an environmentally dangerous gas is used as a basis for the regulating values.

14. A method according to claim 1, wherein the high temperature gas phase process is CVD, LPCVD or CVI.