Method for analyzing samples of a gas in a rotary cement kiln
In a method for analyzing samples of a gas in a rotary cement kiln by at least one gas sampling probe, a first and a second gas sampling probe are provided, wherein the first gas sampling probe is moved so as to reach a sampling position, wherein gas samples are withdrawn from the kiln and analyzed by the first gas sampling probe being in the sampling position, while the second gas sampling probe is kept in a retracted position and is purged, whereupon the second gas sampling probe is moved so as to reach a sampling position, and the first gas sampling probe is moved from the sampling position to the retracted position and is purged, while gas samples are withdrawn from the kiln and analyzed by the second gas sampling probe being in the sampling position.
1. A sampling device for analyzing samples of a gas in a rotary cement kiln by means of gas sampling probes, the sampling device comprising:
first and the second gas sampling probes that are each guided for movement between a retracted position and a sampling position by a respective drive, and
further comprising a control unit that is connected with the drives of the first and second gas sampling probes for controlling movement between the retracted position and the sampling position and for starting and stopping gas analysis, wherein the control unit is configured to control the first and the second gas sampling probes so that the first gas sampling probe is moved so as to reach the sampling position, wherein gas samples are withdrawn from the rotary cement kiln and analyzed by the first gas sampling probe being in the sampling position, while the second gas sampling probe is kept in the retracted position and is purged, whereupon the second gas sampling probe is moved so as to reach the sampling position, and the first gas sampling probe is moved from the sampling position to the retracted position and is purged, while gas samples are withdrawn from the kiln and analyzed by the second gas sampling probe being in the sampling position.
2. The sampling device according to claim 1 , wherein the control unit is configured to control the first and the second gas sampling probes so that after the first gas sampling probe has been purged, the first gas sampling probe is moved so as to reach the sampling position, and the second gas sampling probe is moved from the sampling position to the retracted position and is purged, while gas samples are withdrawn from the kiln and analyzed by means of the first gas sampling probe being in the sampling position.
3. The sampling device according to claim 1 , wherein the first and the second gas sampling probes are guided for movement in a longitudinal direction between the retracted position and the sampling position.
4. The sampling device according to claim 3 , wherein the first and the second gas sampling probes are each driven in a longitudinal direction by a pneumatic drive or an electric drive.
5. The sampling device according to claim 1 , wherein the first and second gas sampling probes each comprise a sampling tube for withdrawing a gas sample from the cement kiln through said sampling tube.
6. The sampling device according to claim 1 , wherein a purge system is provided for purging the first and second gas sampling probes when in their retracted position.
7. The sampling device according to claim 6 , wherein the purge system comprises a blowing system for ejecting a jet of compressed air.