JPH11190501A - Automatically water filling apparatus during stoppage of boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatically water filling apparatus during the stoppage of a boiler which saves time and labor for manual operation of a feed water pump and a feed water flow control valve by an operator at the starting of the boiler and achieves a higher work performance while preventing misoperation by always keeping a drum level of a steam and water drum at a prescribed water level even during the stoppage of the boiler. SOLUTION: A sequencer 38 is provided. During the stoppage of a boiler and when the drum level 19 of a steam drum 1a falls below a prescribed water level, a starting command 36 is outputted to a feed water pump 15 while a switching command 37 is outputted to a drum level adjuster 22 to open the travel of a feed water flow control valve 17 to a prescribed value. On the other hand, during the stoppage of the boiler and when the drum level 19 of the steam drum 1a exceeds the prescribed water level, the outputting of the starting command 36 to the feed water pump 15 while the outputting of the switching command 37 to the drum level adjuster 22 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic water filling apparatus for stopping a boiler.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a boiler for generating auxiliary steam in a power plant or the like has a boiler body 1 in which a steam cylinder 1a is disposed at an upper part and a water cylinder 1b is disposed at a lower part. At the same time, the combustion air is supplied from the combustion air duct 3 through the wind box 4 by the forced draft fan 2, and the fuel F such as light oil is supplied from the fuel supply pipe 5 to the burner 6.
The steam in the heat transfer tube of the boiler body 1 is heated by the generated combustion gas to generate steam,
The steam is taken out from the steam cylinder 1a through the steam pipe 7 and introduced into the auxiliary steam header 8 on the main boiler side, while the combustion gas whose heat has been taken off is discharged from the chimney (not shown) through the flue 9 to the atmosphere. It is supposed to.

In FIG. 3, reference numeral 10 denotes a fuel cut-off valve provided in the middle of the fuel supply pipe 5, reference numeral 11 denotes a main steam stop valve provided in the middle of the steam pipe 7, and reference numeral 12 denotes ignition of propane gas or the like when the boiler is started. Is a burner for ignition to which the fuel F 'is supplied.

On the other hand, a deaerator 13 is mounted on the upper part of the steam cylinder 1a, and water stored in a makeup water tank 14 passes through a water supply pipe 16 by an operation of a water supply pump 15, and the deaeration is performed. The steam cylinder 1a is supplied via the vessel 13.

The amount of water supplied to the steam cylinder 1a is adjusted by increasing or decreasing the opening of a feed water flow control valve 17 provided in the middle of the feed pipe 16. The opening of the control valve 17 is determined by the drum level meter 1
The output from the drum level controller 22 is based on the water level inside the steam cylinder 1a, that is, the drum level 19 detected by the steam flow meter 8, and the steam flow rate 21 detected by the steam flow meter 20 provided in the middle of the steam pipe 7. Opening command 23
Is controlled by the

As shown in FIG. 4, the drum level controller 22 obtains a difference between a specified water level 24 of the drum level inside the steam cylinder 1a and an actual drum level 19 detected by the drum level meter 18. A subtractor 26 that outputs a level deviation 25 and a basic opening command 27 of the feedwater flow control valve 17 for proportionally integrating the drum level deviation 25 output from the subtractor 26 to eliminate the drum level deviation 25 are output. Proportional integral controller 28 and steam flow meter 20
A function generator 30 for obtaining and outputting a corrected opening command 29 for the feedwater flow control valve 17 based on the steam flow 21 detected by the control unit 30 and a basic opening of the feedwater flow control valve 17 output from the proportional-integral controller 28. The function generator 30
Opening command 29 for the water supply flow control valve 17 output from the
And an adder 31 that outputs an opening command 23 of the water supply flow rate control valve 17 and an opening command 2 that is output from the adder 31.
3 is input, and in the case of automatic operation, the opening degree command 23 is output as it is as the opening degree instruction 23 'to the water supply flow rate control valve 17, while in the case of manual operation, the opening degree command 23' based on manual operation by an operator. And an automatic / manual switching device 32 that outputs the control signal to the water supply flow rate control valve 17. A function as shown in FIG. 5 is input to the function generator 30, and the function is set to a correction opening command 29 of the water supply flow rate control valve 17 in substantially proportion to the increase or decrease of the steam flow rate 21. Is increased or decreased.

During operation of the boiler as described above, the drum level meter 18 detects the drum level 19 inside the steam cylinder 1a, and the steam flow meter 20 introduces the steam flow introduced into the main boiler side auxiliary steam header 8. 2
1 is detected and the subtractor 26 of the drum level controller 22 outputs the specified water level 24 of the drum level inside the steam cylinder 1a.
And the actual drum level 19 detected by the drum level meter 18 is obtained, and the drum level deviation 2
5 is output to a proportional-integral controller 28, and the drum-level deviation 25 output from the subtracter 26 is proportionally integrated in the proportional-integral controller 28 to control the feed water flow rate control valve 17 for eliminating the drum level deviation 25. While the basic opening command 27 is output to the adder 31, the correction opening command 29 for the feed water flow control valve 17 is obtained in the function generator 30 based on the steam flow 21 detected by the steam flow meter 20, The basic opening command 27 of the water supply flow control valve 17 output from the proportional-integral controller 28 is output to the adder 31 and the feed water flow control valve 17 output from the function generator 30 is corrected. The opening command 29 is added, and the opening command 23 of the water supply flow rate control valve 17 is output as it is via the automatic / manual switch 32 as the opening command 23 '. Depending regulated the opening of the feed water flow rate control valve 17, is adjusted the amount of water to be supplied to the brackish drum 1a, provisions drum level 19 of 該汽 water body 1a water level 24
Is to be held.

When the boiler is stopped as described above, the operator manually throttles the main steam stop valve 11 at a required speed such that the ACC (automatic combustion control) of the boiler follows the boiler. After reducing the load to the minimum load of about 1/5 of the rated value, the stop button is pressed to close the fuel cutoff valve 10, cut off the supply of the fuel F to the burner 6, extinguish the burner 6, and stop the boiler. On the other hand, the water supply pump 15
Is stopped, and the water supply flow control valve 17 is fully closed.

By the way, conventionally, when the boiler is stopped, the drum level 19 of the steam cylinder 1a may drop below the specified water level 24. Thus, the drum level 19 of the steam cylinder 1a becomes lower than the specified water level. If the boiler is started in a state where it is lower than 24, the boiler may be empty, which may have an unfavorable effect on the boiler main body 1. Therefore, when the boiler is started, an operator goes to the site and supplies water manually. The pump 15 is started, the feed water flow control valve 17 is opened, the water stored in the makeup water tank 14 is supplied to the steam cylinder 1a, and the drum level 19 of the steam cylinder 1a is raised to a specified water level 24, and then the boiler Is started.

[0010]

However, as described above, when the boiler is started, the operator manually starts the water supply pump 15 and opens the water supply flow control valve 17 to store the water in the makeup water tank 14. When the boiler is started, the operator has to go to the site every time the boiler is started up, and the workability is poor. There is also a risk that the boiler will be started without raising the water level to the specified water level 24.

The present invention has been made in view of the above circumstances, and it is possible to always maintain the drum level of the steam cylinder at a specified water level even when the boiler is stopped. An object of the present invention is to provide an automatic flooding device during stoppage of a boiler, which can save labor for manual operation, improve workability, and prevent operation errors.

[0012]

According to the present invention, during operation of a boiler, the opening of a feedwater flow control valve provided in the middle of a feedwater pipe is output from a drum level controller based on the drum level of a steam cylinder. By controlling the amount of water supplied to the steam cylinder by the operation of the water supply pump by controlling the opening degree command to maintain the drum level of the steam cylinder at a specified water level, while the boiler is stopped, the water supply pump is controlled. The automatic water filling device during the stop of the boiler, which stops the boiler, outputs a start command to the water supply pump when the boiler is stopped and the drum level of the steam cylinder falls below a specified water level; and While the switching command for opening the opening of the feedwater flow control valve to the specified opening is output to the drum level controller, when the boiler is stopped and the drum level of the steam cylinder is equal to or higher than the specified water level, In which according to the automatic water applying apparatus during the stop of the boiler, characterized in that it comprises a sequencer to stop the output of the switching instruction output start instruction to the stopped and the drum level controllers for the feed water pump.

According to the above means, the following effects can be obtained.

When the boiler is stopped, the feedwater pump is stopped. In this state, if the drum level of the steam cylinder falls below a specified water level, a start command is output from the sequencer to the feedwater pump to start the feedwater pump. At the same time, a switching command is output to the drum level controller, the opening of the feedwater flow control valve is opened to the specified opening, and water is supplied to the steam cylinder.

When water is supplied to the steam cylinder and the drum level of the steam cylinder reaches a specified water level, the output of a start command to the water supply pump from the sequencer is stopped, and the water supply pump is stopped. The output of the switching command to the level controller is stopped.

As a result, even when the boiler is stopped, the drum level of the steam cylinder is always maintained at the specified water level. When the boiler is started, the operator goes to the site and manually operates the water supply pump and the water supply flow control valve. This eliminates the need to perform the operation, improves the workability, and prevents the boiler from being activated without raising the drum level of the steam cylinder to the prescribed water level due to an operator's operation error or the like.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of the embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 3 and 4 represent the same components, and the basic configuration is as follows. 3 and FIG. 4 are the same as the conventional one, but the features of the present embodiment are, as shown in FIG. 1 and FIG. 2, an adder 31 of a drum level controller 22 and an automatic / manual switch. During operation of the boiler, the opening command 23 output from the adder 31 is output as it is to the automatic / manual switching device 32 as the opening command 23 "while the boiler is stopped and the steam cylinder is operated. When the drum level 19 of 1a falls below the specified water level 24, the specified opening command 34 of the water supply flow rate control valve 17 preset in the setting device 33 is automatically set to the opening command 23 ".
A switch 35 for outputting to the manual switch 32 is provided.
Drum level 1 of boiler cylinder 1a while boiler is stopped
When 9 falls below the specified water level 24, the water supply pump 1
5, a start command 36 is output to the power panel 15a and a switch command 37 is output to the switch 35 of the drum level controller 22, while the boiler is stopped and the drum level 19 of the steam cylinder 1a is at the specified water level. In the case of 24 or more, the output of the start command 36 to the power board 15a of the water supply pump 15 is stopped and the drum level controller 22 is stopped.
The sequencer 38 for stopping the output of the switching command 37 to the switching unit 35 is additionally provided.

Next, the operation of the illustrated example will be described.

During operation of the boiler, the drum level 19 inside the steam cylinder 1a is detected by the drum level meter 18 and introduced into the main steam generator side auxiliary steam header 8 by the steam flow meter 20, as in the conventional case. The steam flow rate 21 is detected, and a subtractor 26 of the drum level controller 22 calculates a difference between the specified water level 24 of the drum level inside the steam cylinder 1a and the actual drum level 19 detected by the drum level meter 18. Then, the drum level 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 supply water for eliminating the drum level deviation 25. While the basic opening degree command 27 of the flow control valve 17 is output to the adder 31, it is detected by the steam flow meter 20. Correction opening command 29 of the feed water flow rate control valve 17 in the function generator 30 based on the steam flow rate 21
Is output to the adder 31 and the adder 31
The function generator 30 is added to the basic opening command 27 of the feed water flow rate control valve 17 output from the proportional integration controller 28 at
Opening command 29 for the water supply flow control valve 17 output from the
Is added, and the opening degree command 23 of the feedwater flow control valve 17 is output to the switch 35.

Since the switching command 37 is not output from the sequencer 38 to the switch 35 of the drum level controller 22 during the operation of the boiler, the opening command 23 output from the adder 31 is not output. It is output to the automatic / manual switch 32 via the switch 35 as it is as the opening command 23 ″,
The automatic / manual switch 32 outputs the opening degree command 23 'as it is, and the opening degree of the water supply flow rate control valve 17 is adjusted according to the opening degree command 23', so that the amount of water supplied to the steam cylinder 1a is reduced. As a result, the drum level 19 of the steam cylinder 1a is maintained at the specified water level 24.

On the other hand, when the boiler is stopped, the feedwater pump 15 is stopped, and the feedwater flow control valve 17 is fully closed. In this state, the drum level 19 of the steam cylinder 1a falls to the specified water level 24.
In the case of a further decrease, a start command 36 is output from the sequencer 38 to the power board 15a of the feed pump 15 to start the feed pump 15 and a switch command 37 to the switch 35 of the drum level controller 22 is issued. Since the switching device 35 is output to switch the setting device 33 to the setting device 33 side, the specified opening command 34 of the water supply flow rate control valve 17 preset in the setting device 33 becomes the opening command 23 ″ as the automatic / manual switching device 32.
Output from the automatic / manual switch 32 to the opening command 2
3 ', the opening degree command 23', that is, the specified opening degree command 34, opens the water supply flow rate control valve 17 from the fully closed state to a specified opening degree (for example, an opening degree of 25%), and water is supplied to the steam cylinder 1a. Replenished.

When water is supplied to the steam cylinder 1a and the drum level 19 of the steam cylinder 1a reaches a specified water level 24,
Power board 15 of feed pump 15 from sequencer 38
a, the output of the start command 36 is stopped, and the water supply pump 15 is stopped. At the same time, the output of the switch command 37 to the switch 35 of the drum level controller 22 is stopped, and the switch 35 returns to the adder 31 side. Can be switched.

Incidentally, even if the switch 35 is switched back to the adder 31 side and the opening of the feed water flow control valve 17 changes according to the opening command 23 based on the drum level 19, the feed pump 15 is stopped. Therefore, the drum level 19 is not affected at all.

As a result, even when the boiler is stopped, the drum level 19 of the steam cylinder 1a is always maintained at the specified water level 24. When the boiler is started, the operator goes to the site to feed the water supply pump 15 and the water supply flow rate. This eliminates the need to manually operate the valve 17, improving workability, and starting the boiler without raising the drum level 19 of the steam cylinder 1 a to the specified water level 24 due to an operator's operation error or the like. Is also gone.

In this way, even when the boiler is stopped, the drum level 19 of the steam cylinder 1a can be always maintained at the specified water level 24.
5 and the trouble of manually operating the feed water flow control valve 17 can be omitted, workability can be improved, and operation errors can be prevented.

It should be noted that the automatic water filling device for stopping the boiler of the present invention is not limited to the above-described illustrated example, and it is needless to say that various changes can be made without departing from the gist of the present invention. is there.

[0028]

As described above, according to the automatic water filling apparatus for stopping the boiler of the present invention, the drum level of the steam cylinder can always be maintained at the specified water level even during the stop of the boiler. This eliminates the need for the operator to manually operate the water supply pump and the water supply flow rate control valve at the time of startup, thereby improving the workability and preventing operational errors.

[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 block diagram of a drum level controller and a sequencer according to an example of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional example.

FIG. 4 is a block diagram of a conventional drum level controller.

FIG. 5 is a diagram showing functions set in the function generator shown in FIGS. 2 and 4;

[Explanation of symbols]

 1a Braice drum 15 Water supply pump 16 Water supply pipe 17 Water supply flow rate control valve 19 Drum level 22 Drum level controller 23 'Opening command 24 Specified water level 34 Specified opening command 35 Switching device 36 Start command 37 Switching command 38 Sequencer

Claims (1)

[Claims] In the boiler operation, the opening of a water supply flow control valve provided in the middle of a water supply pipe is controlled by an opening command output from a drum level controller based on a drum level of a steam cylinder. By adjusting the amount of water to be supplied to the steam cylinder by the operation of the water supply pump, while maintaining the drum level of the steam cylinder at a specified water level, while the boiler is stopped, the boiler is configured to stop the water supply pump When the automatic water filling device is stopped, the boiler is stopped, and when the drum level of the steam cylinder falls below the specified water level, a start command is output to the feedwater pump and the opening of the feedwater flow control valve is adjusted. While a switching command for opening to the specified opening degree is output to the drum level controller, if the boiler is stopped and the drum level of the steam cylinder is equal to or higher than a specified water level, the water supply pump Dynamic instruction stops outputting and the drum level controllers boiler stop during automatic water applying apparatus characterized by comprising a sequencer stops outputting the switching command to.