Monitoring method

Abstract

The invention relates to a method for monitoring an operating status of an anode furnace, wherein the anode furnace is formed from a plurality of heating ducts (12) and furnace chambers, wherein the furnace chambers serve for receiving anodes and the heating ducts serve for controlling the temperature of the furnace chambers, wherein the anode furnace comprises at least one furnace unit (11) having a heating zone (18), a firing zone (19) and a cooling zone (20), wherein a suction device (15) is arranged in the heating zone and a burner device (16) is arranged in the firing zone, wherein, by means of the burner device, combustion air is heated up in the heating ducts of the firing zone, wherein, by means of the suction device, hot air is sucked out of the heating ducts of the heating zone, wherein a suction output of the suction device is determined, and wherein a pressure in the heating duct is measured, wherein a volumetric flow in the heating duct is determined from a ratio of suction output and pressure.

Claims

1. A method for monitoring an operating status of furnace, wherein the furnace is formed from a plurality of heating ducts and furnace chambers, wherein the heating ducts serve for controlling the temperature of the furnace chambers, wherein the furnace includes at least one furnace unit having a heating zone, a firing zone and a cooling zone, wherein a suction device is arranged in the heating zone and a burner device is arranged in the firing zone, said method comprising: heating combustion air in the heating ducts of the firing zone with the burner device, drawing hot air out of at least one of the plurality of heating ducts in the heating zone using the suction device; determining a suction output of the suction device by determining a throttle position of a throttle of the suction device; measuring a pressure in the at least one of the plurality of heating ducts; and determining a ratio of the suction output and pressure, and using the ratio to evaluate the operating status of the furnace.

2. The method according to claim 1, including measuring a pressure in at least one of the heating duct of the heating zone and the firing zone.

3. The method according to claim 2, including measuring a pressure in the suction device.

4. The method according to claim 3, including determining the volumetric flow in heating duct from a ratio of suction output and pressure in the suction device and from the ratio of suction output and pressure in the heating duct.

5. The method according to claim 3, including the step of comparing a respective pressure in at least one of the plurality of heating ducts to the pressure in the suction device.

6. The method according to claim 1, including determining the volumetric flow in the heating duct of at least one of the heating zone and the firing zone.

7. The method according to claim 1, including the step of determining a volumetric flow from the ratio, and using the volumetric flow to evaluate the operating status.

8. The method according to claim 1, including measuring a temperature in the heating duct.

9. The method according to claim 8, including measuring a temperature gradient in the heating duct.

10. The method according to claim 9, including measuring at least one of the temperature gradient and a temperature in at least one of a collecting duct of the suction device, the heating zone, and the firing zone.

11. The method according to claim 9, including calculating a density change of air in the heating duct from the temperature gradient and from the temperature, wherein the density change is used for determining the volumetric flow.

12. The method according to claim 9, including evaluating an operating status from a ratio of temperature gradient and volumetric flow.

13. The method according to claim 7, including evaluating the operating status, wherein, in case of a deviation from a presupposed operating status, the burner device is switched off.

14. The method according to claim 13, in which operating status parameters that describe the operating status are stored, said method further including evaluating the current operating status by comparing stored operating status parameters to the current ones.

15. The method according to claim 1, including performing, before the initiation of operation of the furnace unit, a test of measuring sensors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures:

(2) FIG. 1: shows a schematic illustration of an anode furnace in a perspective view;

(3) FIG. 2: shows a schematic illustration of a furnace unit of the anode furnace in a longitudinal sectional view;

(4) FIG. 3: shows a temperature distribution in the furnace unit;

(5) FIG. 4: shows a graphic illustration of the ratio of the volumetric flow to the operating status parameters;

(6) FIG. 5: shows a graphic ratio illustration of the volumetric flow to the temperature gradient;

(7) FIG. 6: shows a flow chart for an embodiment of the method for monitoring an operating status.

DETAILED DESCRIPTION OF THE DISCLOSURE

(8) A combined view of FIGS. 1 and 2 shows a schematic illustration of an anode furnace 10 having a furnace unit 11. The anode furnace 10 includes a plurality of heating ducts 12 which run in parallel along furnace chambers 13 that are located inbetween. In this case, the furnace chambers 13 serve for receiving anodes which are not illustrated in greater detail here. The heating ducts 12, presenting the shape of a meander, run in the longitudinal direction of the anode furnace 10 and have evenly spaced heating duct openings 14, which are respectively covered by a heating duct covering which is not illustrated in greater detail here.

(9) The furnace unit 11 furthermore comprises a suction device 15, a burner device 16 and a blower device 17. Their position at the anode furnace 10 is in each case defined, in a manner conditioned by function, by a heating zone 18, a firing zone 19 and a cooling zone 20. Over the course of the production process of the anodes, the furnace unit 11 is shifted relative to the furnace chambers 13 or to the anodes by tramming the devices 15 to 17 in the longitudinal direction of the anode furnace 10, such that all anodes that are situated in the anode furnace 10 pass through the zones 18 to 20.

(10) The suction device 15 is substantially formed from a collecting duct 21 which is connected to a waste gas cleaning system, which is not illustrated here, via an annular duct 22. The collecting duct 21, in each case via a connecting duct 23, is again connected to a heating duct opening 14, wherein a throttle 24 is arranged at the connecting duct 23 here. A measuring sensor, which is not illustrated here, for measuring the pressure within the collecting duct 21, and a further measuring sensor 25 for measuring the temperature in each heating duct 12 are furthermore directly arranged in front of the collecting duct 21, being connected to the same via a data line 26. In the heating zone 18, in addition, a measuring ramp 27 is arranged having measuring sensors 28 for each heating duct 12. By means of the measuring ramp 27, a pressure and a temperature in the portion in question pertaining to the heating duct 12 can be ascertained.

(11) The burner device 16 comprises three burner ramps 29 having burners 30 and measuring sensors 31 for each heating duct 12. In the heating duct 12 in each case, the burners 30 combust a flammable combustible material, wherein a burner temperature is measured by means of the measuring sensors 31. In this way, it becomes possible to set a desired burner temperature in the range of the firing zone 19.

(12) The cooling zone 20 comprises the blower device 17 which is formed from a feed duct 32 having, in each case, connecting ducts 33 and throttles 34 for connecting to the heating ducts 12. Via the feed duct 32, fresh air is blown into the heating ducts 12. The fresh air cools the heating ducts 12 or the anodes that are situated in the furnace chambers 13 in the range of the cooling zone 20, wherein the fresh air is continuously heated until it reaches the firing zone 19. A chart of the temperature distribution relating to the length of a heating duct 12 and to the zones 18 to 20 can be taken from FIG. 3 in this respect. In the cooling zone 20, a measuring ramp 35 having measuring sensors 36 is furthermore arranged. The measuring sensors 36 serve for recording a pressure in the respective heating ducts 12. In the range of the measuring sensors 36, the pressure in the heating duct 12 essentially reaches the value of zero, wherein a positive pressure is formed between the measuring sensors 36 and the blower device 17 and a negative pressure is formed in the heating ducts 12 between the measuring sensors 36 and the suction device 15. Consequently, the fresh air flows through the heating ducts 12 to the suction device 15, starting from the blower device 17.

(13) With the sequence of the method which is illustrated by way of example in FIG. 6, it is now possible to determine a volumetric flow of the air and thus an operating status. Referring to the anode furnace according to FIGS. 1 and 2, all measuring sensors 25, 28, 31, 36 as well as the measuring sensor for determining the position of the throttle 24 of the suction device 15 are tested, the latter sensor not being illustrated here.

(14) In this way, it can be ensured that measurement values of potentially defective measuring sensors are not read out. Said check is performed directly after tramming the furnace unit 11 and repeatedly initiating the operation of the devices 15 to 17. During operation of the furnace unit 11, a temperature in the heating duct 12 as well as a temperature gradient are recorded by means of the measuring sensor 25 or 28, wherein said measurement values are utilized for correcting the density of the air or hot air that is present in the heating duct 12. In parallel, by means of the measuring sensors 28, a position of the respective throttles 24 is measured, the pressure in the collecting duct 21 is measured and the pressure in the heating ducts 12 is measured. Ratios are formed in each case from the measurement values for the position of the throttle and from the respective measurement values for a negative pressure in the collecting duct 21 and in the heating duct 12, from which ratios a volumetric flow in the heating duct 12 can be derived together with the above-described density correction. An operating status for the volumetric flow is in turn determined from a ratio of volumetric flow and temperature gradient in the heating duct 12. Here, there is provision for storing corresponding measurement values or operating status parameters, thereby calibrating an operating status or describing a proper operating status. During repeating operating phases, it is then possible to perform a comparison between the calibrated or presupposed proper operating status and the current operating status.

(15) Said comparison can, as illustrated in FIG. 4, for example be effected by comparing a current operating pressure at a throttle to a presupposed operating pressure. It is also possible to evaluate a ratio of volumetric flow and temperature gradient, as illustrated in FIG. 5. In the illustrated example, in a range 37 of the chart, the ratio could be evaluated to be proper for the operating status, in a range 38, it could be evaluated to be critical and in a range 39, it could be evaluated to be insufficient. Said operating statuses can, for example, be signaled to an operator as a graphic illustration in the manner of a traffic light indicator or also acoustically.