JP4182620B2 - Boiler drum level measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drum drum level measuring apparatus.
[0002]
[Prior art]
In general, as shown in FIG. 4, a boiler for generating auxiliary steam in a power plant or the like is a forced air blower in a boiler body 1 in which a brackish water drum 1a is arranged at the top and a water drum 1b is arranged at the bottom. The combustion air is supplied from the combustion air duct 3 through the wind box 4 by the fuel gas 2 and the fuel F such as light oil is supplied from the fuel supply pipe 5 and injected from the burner 6 to be burned. Then, the water in the heat transfer pipe of the boiler body 1 is heated to generate steam, the steam is taken out from the steam cylinder 1a through the steam pipe 7, and introduced into the main boiler side auxiliary steam header 8, while the heat is taken away. The combustion gas is discharged from a chimney (not shown) through the flue 9 to the atmosphere.
[0003]
In FIG. 4, 10 is a fuel cutoff valve provided in the middle of the fuel supply pipe 5, 11 is a main steam stop valve provided in the middle of the steam pipe 7, and 12 is an ignition fuel F such as propane gas when the boiler is started. 'Is an ignition burner supplied.
[0004]
On the other hand, a deaerator 13 is attached to the upper part of the brackish water barrel 1a, and the water stored in the makeup water tank 14 is supplied to the deaerator 13 via the water supply pipe 16 by the operation of the water supply pump 15. Via the above, the brackish water barrel 1a is supplied.
[0005]
The amount of water supplied to the brackish water barrel 1 a is adjusted by increasing or decreasing the opening of a feed water flow rate adjustment valve 17 provided in the middle of the feed water pipe 16, and the feed water flow rate adjustment valve 17. Is based on the water level inside the brackish water drum 1a detected by the drum level measuring device 18, that is, the drum level 19, and the steam flow rate 21 detected by the steam flow meter 20 provided in the middle of the steam pipe 7. The opening level command 23 ′ output from the drum level controller 22 is controlled.
[0006]
As shown in FIG. 5, the drum level controller 22 obtains the difference between the drum level specified water level 24 inside the brackish drum 1a and the actual drum level 19 detected by the drum level measuring device 18 to obtain the drum level deviation. 25, and a basic opening degree command 27 of the feed water flow rate adjusting valve 17 for eliminating the drum level deviation 25 by proportionally integrating the drum level deviation 25 outputted from the subtractor 26. A proportional-integral controller 28, a function generator 30 that calculates and outputs a correction opening degree command 29 of the feed water flow rate control valve 17 based on the steam flow rate 21 detected by the steam flow meter 20, and an output from the proportional-integral controller 28 The corrected opening degree command 29 of the feed water flow rate adjusting valve 17 output from the function generator 30 is added to the basic opening degree command 27 of the feed water flow rate regulating valve 17 to be adjusted. An adder 31 that outputs an opening command 23 of the valve 17 and an opening command 23 output from the adder 31 are input. In the automatic case, the opening command 23 is used as it is as an opening command 23 '. While being output to the flow rate control valve 17, in the case of manual operation, an automatic / manual switch 32 is provided that outputs an opening degree command 23 ′ based on the manual operation of the operator to the feed water flow rate control valve 17. ing.
[0007]
As shown in FIG. 6, the function generator 30 is input with a function for increasing / decreasing the correction opening degree command 29 of the feed water flow rate control valve 17 substantially in proportion to the increase / decrease of the steam flow rate 21. .
[0008]
During the operation of the boiler as described above, the drum level 19 inside the brackish water drum 1a is detected by the drum level measuring device 18, and the steam flow rate 21 introduced into the main boiler side auxiliary steam header 8 by the steam flow meter 20 is determined. The subtractor 26 of the drum level controller 22 detects the difference between the specified water level 24 of the drum level inside the brackish drum 1a and the actual drum level 19 detected by the drum level measuring device 18 to obtain the drum level. The deviation 25 is output to the proportional integral controller 28, and the drum level deviation 25 output from the subtractor 26 is proportionally integrated in the proportional integral controller 28 to eliminate the drum level deviation 25. 17 basic opening command 27 is output to the adder 31 and detected by the steam flow meter 20. Based on the steam flow rate 21, the function generator 30 calculates a correction opening degree command 29 of the feed water flow rate adjustment valve 17 and outputs it to the adder 31, and the adder 31 outputs the feed water flow rate from the proportional-plus-integral regulator 28. The correction opening degree command 29 of the feed water flow rate control valve 17 output from the function generator 30 is added to the basic opening degree command 27 of the control valve 17 so that the opening degree command 23 of the feed water flow rate control valve 17 is an automatic / manual switch. 32 is output as it is as an opening degree command 23 ', the opening degree of the feed water flow rate adjustment valve 17 is adjusted according to the opening degree command 23', and the amount of water replenished to the brackish water barrel 1a is adjusted, The drum level 19 of the brackish water drum 1 a is held at the specified water level 24.
[0009]
By the way, as shown in FIG. 7, the brackish water barrel 1a is formed of a perforated plate such as a punching metal for preventing water undulation and suppressing fluctuation of the water level in the longitudinal direction of the brackish water drum 1a. A baffle plate 33 and a swash plate 35 are disposed to support the baffle plate 33 and the baffle plate 33, the baffle plate 34, and the swash plate 35 are used to support the baffle plate 33. The inner and lower portions are partitioned into a brackish water mixture portion 36 in which steam and water are mixed, and a saturated water portion 37 in which saturated water is accumulated. Note that a gap is formed between the lower end of the swash plate 35 and the inner surface of the bottom of the brackish water drum 1a, and even if the water level in the brackish water drum 1a is lower than the baffle plate 33, the brackish water mixture The portion 36 and the saturated water portion 37 communicate with each other so that the water level of the brackish water mixture portion 36 and the water level of the saturated water portion 37 are the same.
[0010]
Further, as shown in FIG. 7, the drum level measuring device 18 connects a reservoir 39 in which water for holding a reference level is stored via an upper connection pipe 38 to the upper part of the brackish water drum 1a. The reservoir inner head detection chamber 41 is connected to the bottom of 39 via a connection pipe 40, and the drum inner head detection chamber 43 is connected to the saturated water portion 37 in the lower part of the brackish water barrel 1a via a lower connection pipe 42, A differential pressure detector 44 for detecting the differential pressure between the reservoir head detection chamber 41 and the drum head detection chamber 43 as the drum level 19 is provided. During operation of the boiler, the reservoir 39 is provided. Is maintained substantially constant, and the differential pressure detector 44 detects the differential pressure between the reservoir head detection chamber 41 and the drum head detection chamber 43. And, the brackish water body 1a inside the drum level 19 is adapted to be measured.
[0011]
[Problems to be solved by the invention]
However, in the case of the boiler as described above, water in the saturated water portion 37 in the brackish water barrel 1a is temporarily sucked out from the gap at the lower end portion of the swash plate 35 toward the brackish water mixture portion 36, and the water level in the saturated water portion 37 is A descending phenomenon sometimes occurred.
[0012]
Such a phenomenon is temporary and returns to the original state over time. However, if the drum level 19 inside the brackish water drum 1a is detected by the saturated water portion 37 as in the prior art, the saturated water portion It is determined that the drum level 19 has dropped throughout the brackish water drum 1a even though only the water level at 37 is temporarily lowered, and in some cases, a trip command for preventing the boiler from blowing is output. The boiler had a problem that it tripped.
[0013]
In view of such a situation, the present invention can always accurately measure the drum level inside the brackish water tank even if a phenomenon that the water level in the saturated water portion falls occurs, and avoids the boiler from being tripped. An object of the present invention is to provide a drum level measuring device for a boiler.
[0014]
[Means for Solving the Problems]
The present invention detects a drum level by detecting a differential pressure between a head in a reservoir that is connected to an upper portion of the brackish water cylinder and stores water for maintaining a reference level, and a head in the brackish water drum. A drum level measuring device for a boiler that has a cylindrical drum level detection in which a slit having a required width extending in the vertical direction is formed on a side surface in a brackish water mixture section partitioned from a saturated water section in a brackish water drum The present invention relates to a drum drum level measuring apparatus for a boiler, characterized in that a chamber is provided upright and a head in a brackish water drum is detected through the drum level detecting chamber.
[0015]
According to the above means, the following operation can be obtained.
[0016]
During the operation of the boiler, the reference level by the reservoir is kept substantially constant, and water flows from the slit into the drum level detection chamber standing in the brackish water mixture portion of the brackish water drum. The water level in the level detection chamber is maintained at the same level as the water level in the bracelet, and the differential pressure between the head in the reservoir and the head in the bracelet through the drum level detection chamber is detected. By doing so, the drum level inside the brackish water drum is measured.
[0017]
As a result, even if a phenomenon occurs in which water in the saturated water section in the brackish water tank is temporarily sucked out to the brackish water mixture section and the water level in the saturated water section drops, Unlike the case where the drum level is detected in the saturated water section, it is not determined that the drum level has fallen throughout the brackish water drum, and no trip command for preventing the boiler from blowing is output. It is also possible to avoid tripping.
[0018]
Note that the brackish water mixture part has a high temperature and a lot of bubbles, and it is measured when the head of the brackish water mixture part is simply detected as a head in the brackish water cylinder without providing a drum level detection chamber. Although the accuracy of the drum level may decrease due to the influence of air bubbles, it is difficult for air bubbles to enter the drum level detection chamber from the slit with the required width extending in the vertical direction. There is no worry that the level accuracy will be affected by bubbles.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
1 to 3 show an example of an embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 4 to 7 denote the same components, and the basic configuration is shown in FIGS. Although it is the same as that of the prior art shown in FIG. 7, the feature of this illustrated example is that, as shown in FIGS. 1 to 3, the brackish water mixture portion 36 partitioned from the saturated water portion 37 in the brackish water barrel 1 a. A cylindrical drum level detection chamber 46 having a slit 45 having a required width (about 3 [mm]) extending in the vertical direction is formed on the side, and the drum level detection chamber 46 is interposed through the drum level detection chamber 46. It is in the point comprised so that the head in the brackish water drum 1a might be detected.
[0021]
The drum level detection chamber 46 is formed with slits 45 extending in the longitudinal direction on the side surface of a tubular body 47 such as a steel pipe, and both ends of the tubular body 47 are closed by disk-shaped lid plates 48 and 49. In the state where the cylindrical body 47 is erected, an air hole 50 is formed in the lid plate 48 positioned on the upper side, and a drain hole 51 is formed in the bottom of the cylindrical body 47. It has a configuration in which a nozzle 53 that protrudes in the radial direction and has a joint member 52 attached to the tip thereof protrudes, and a lower portion that communicates with the nozzle 53 of the drum level detection chamber 46 and the head detection chamber 43 in the drum. The connecting pipe 42 is connected via a connecting pipe 54.
[0022]
Next, the operation of the illustrated example will be described.
[0023]
During the operation of the boiler, the reference level by the reservoir 39 is kept substantially constant, and the drum level detection chamber 46 standing in the brackish water mixing part 36 of the brackish water drum 1a has water from the slit 45. The water level in the drum level detection chamber 46 is maintained at the same level as the water level in the brackish water tank 1a. The drum level detection chamber 46 and the in-drum head detection chamber 43 are provided with nozzles 53. And the joint member 52, the connecting pipe 54, and the lower connection pipe 42, so that the differential pressure detector 44 detects the differential pressure between the reservoir internal head detection chamber 41 and the drum internal head detection chamber 43. Thus, the drum level 19 inside the brackish water drum 1a is measured.
[0024]
As a result, water in the saturated water portion 37 in the brackish water barrel 1a is temporarily sucked out from the gap at the lower end of the swash plate 35 toward the brackish water mixture portion 36, and a phenomenon occurs in which the water level in the saturated water portion 37 drops. However, unlike the conventional case in which the drum level 19 inside the brackish water drum 1a is detected by the saturated water portion 37, it is not determined that the drum level 19 has fallen throughout the brackish water drum 1a. No trip command for preventing air blow is output, and it is possible to prevent the boiler from tripping.
[0025]
Note that the brackish water mixture portion 36 has a high temperature and a large number of bubbles, so that the water in the brackish water mixture portion 36 is simply introduced into the in-drum head detection chamber 43 without providing the drum level detection chamber 46. When trying to detect the head in the brackish water drum 1a, the accuracy of the drum level 19 to be measured may decrease due to the influence of air bubbles, but the required width extending in the vertical direction (approximately 3 [mm]) Since the bubbles are less likely to enter the drum level detection chamber 46 from the slit 45, there is no concern that the accuracy of the measured drum level 19 is affected by the bubbles.
[0026]
In this way, even if the phenomenon that the water level in the saturated water portion 37 drops occurs, the drum level 19 inside the brackish water drum 1a can always be accurately measured, and it is possible to avoid the boiler from being tripped.
[0027]
The boiler drum level measuring device of the present invention is not limited to the illustrated example described above, and it goes without saying that various changes can be made without departing from the scope of the present invention.
[0028]
【The invention's effect】
As described above, according to the drum level measuring device for a boiler of the present invention, the drum level inside the brackish drum can always be accurately measured even if a phenomenon occurs in which the water level in the saturated water portion falls. An excellent effect of avoiding a trip can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.
FIG. 2 is a side view of a drum level detection chamber in an example of an embodiment of the present invention.
3 is a plan view of a drum level detection chamber according to an example of an embodiment of the present invention, and is a view taken in the direction of arrows III-III in FIG. 2;
FIG. 4 is an overall schematic configuration diagram of an example of a boiler.
FIG. 5 is a block diagram of the drum level controller shown in FIG. 4;
FIG. 6 is a diagram representing a function set in the function generator shown in FIG. 5;
FIG. 7 is a schematic configuration diagram of an example of a conventional drum level measuring apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Boiler main body 1a Brackish water drum 18 Drum level measuring device 19 Drum level 36 Brackish water mixture part 37 Saturated water part 39 Reservoir 41 Reservoir head detection chamber 43 Drum head detection chamber 44 Differential pressure detector 45 Slit 46 Drum level detection chamber 47 Cylindrical body 48 Lid plate 49 Lid plate

Claims (1)

Boiler connected to the upper part of the water drum and detecting the drum level by detecting the differential pressure between the head in the reservoir in which water for retaining the reference level is stored and the head in the water drum Drum level measuring device of
A cylindrical drum level detection chamber having a slit having a required width extending in the vertical direction formed on a side surface is provided in a brackish water mixture section partitioned from a saturated water section in a brackish water drum, and the drum level detection chamber A drum level measuring device for a boiler, characterized in that it is configured to detect a head in a brackish water tank.

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