JPH03211301A - Device for safe operation of boiler - Google Patents

Abstract

PURPOSE:To prevent the stopping of a boiler by mistake and its dangerous operation by providing a steam-water level detecting means, supply water flow rate transmitter, steam flow rate transmitter, substractor, and a circuit for judging whether or not a measured value is correct. CONSTITUTION:A boiler is provided with a water wall 2, steam-water cylinder 3, superheater 4, supply water control system, and a circuit 26 for judging whether or not a measured value is correct. The judgement circuit 26 judges whether the steam- water level is high or low and it also monitors the deviation values in the supply water flow rates and the volumes of the generated steam, and on the condition that the steam-water level is higher or lower than a set value and at the same time the deviation values of the supply water flow rate and generated steam volume are larger than a set value, the operation of the boiler is stopped. With this arrangement in the case in which detection pipings (23-1) - (23-4) are clogged and a steam water level detector including the steam-water level oscillators 7 and 18 and monitor switches 12 and 19 for steam-water level high and monitor switches 13 and 20 for steam-water level low and mechanical and electrical elements, etc. of the peripheral equipment, etc. are in trouble, it is possible to prevent the stopping of the boiler by mistake and its dangerous operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a boiler safety operation device, and particularly to a boiler safety device suitable for preventing erroneous boiler stoppages and dangerous operation due to failure of measuring equipment, etc. Regarding driving equipment.

[Conventional technology]

As a safe operation device for this type of boiler, there is a conventional technology as shown in FIG. In the technology shown in Fig. 7, the brackish water network 3
The level of brackish water inside the boiler is measured to determine whether or not it is dangerous to operate the boiler.

Techniques for measuring and determining the level of brackish water include a duplex circuit method and a differential pressure detection method.

There are two further types of duplex circuit systems.

One method is to determine that the operation of the boiler is dangerous when both of the brackish water level transmitters 7 and 18 provided at both ends of the brackish water network 3 in the axial direction detect a high level or a low level. Another method uses at least a brackish water level transmitter 7.
When any one of 18 detects a high level or a low level, it is determined that the operation of the boiler is dangerous.

As shown in FIG. 7, the differential pressure detection method includes a set of a transmitter inlet stop valve and a transmitter blow valve 8.1o on the high pressure side, which are provided at both ends of the brackish water network 3 in the axial direction. Detects the difference between set 1, low pressure side transmitter stop valve, transmitter blow valve set 14.16 and set 15.17, and when the differential pressure becomes abnormal, it is determined that boiler operation is dangerous. do.

[Problem to be solved by the invention]

Among the conventional techniques, the duplex circuit system has the following problems.

In other words, in the duplex circuit method, when both the brackish water level transmitters 7 and 18 installed at both axial ends of the brackish water network 3 detect a high or low level, it is determined that the boiler operation is dangerous. If either one of the brackish water level transmitters 7.18 is out of order, it cannot be determined that operation of the boiler is dangerous even if the brackish water level is actually high or low.

On the other hand, when either one of the brackish water level transmitters 7.18 installed at both axial ends of the brackish water network 3 in the duplex circuit system detects a high level or a low level, the operation of the boiler is dangerous. In this method, if one of the brackish water level transmitters 7.18 malfunctions and transmits a high or low level, it is incorrectly determined that the boiler operation is dangerous, even if the brackish water level is actually normal. This will cause the boiler to stop operating.

In addition, in the differential pressure detection method, if the transmitter blow valve 16 on the low pressure side shown in FIG. 7 leaks and the amount of drain in the detection pipe 23 decreases, the pressure on the low pressure side increases or decreases due to fluctuations in the liquid level. Even though the brackish water level has not actually fluctuated, it appears that the brackish water level has increased. As a result, there is a risk that an operator may erroneously operate a water supply control valve, turn off the water supply, operate the boiler, and run the boiler dry.

In other words, the differential pressure detection method described above may cause the following problems.

(1) If the valve in the detection pipe becomes clogged, the measured value may not change even if the actual level of brackish water changes.

(2) The transmitter blow valve may leak, causing the brackish water level to increase or decrease in appearance.

(3) No response can be taken when the brackish water level transmitter malfunctions due to an electrical or mechanical failure inside the brackish water level transmitter.

(4) There is a difference in temperature between the high pressure side and low pressure side of the detection piping,
It is not possible to deal with errors in differential pressure detection due to differences in specific gravity.

Providing fault diagnosis means for each of the above-mentioned problems will only make the system more complicated, will have little effect, and may even lead to new troubles.

The purpose of the present invention is to avoid complicating the system by adding a fault diagnosis function to each individual measuring device, and to deal with failures of the entire measurement system including the mechanical and electrical elements of the measuring device. Therefore, it is an object of the present invention to provide a safe operation device for a boiler that can prevent erroneous stoppage and dangerous operation of the boiler.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a brackish water level detection means that measures and outputs the brackish water level in the brackish water brain, a water supply flow rate transmitter that measures and outputs the water supply flow rate to the brackish water network, and a brackish water flow rate transmitter that measures and outputs the brackish water level in the brackish water network. A steam flow rate transmitter that measures and outputs the amount of steam generated, and a subtractor that calculates and outputs a deviation value between the feed water flow rate and the amount of generated steam, are provided, and the measured values are obtained from the brackish water level detection means and the subtracter, respectively. The boiler is equipped with a circuit for determining whether the measured value is correct or not, which stops the boiler when the intake and brackish water levels are higher or lower than the set value and the deviation value between the feed water flow rate and the amount of steam generated is larger than the set value.

In order to achieve the above object, the present invention also provides a furnace pressure gauge that measures and outputs the pressure inside the furnace, and a flue differential pressure gauge that measures and outputs the differential pressure between the furnace and the flue after the induced draft fan. and a device that receives measured values from the furnace pressure gauge and the flue differential pressure gauge, respectively, and determines whether the measured values are correct or incorrect to stop the boiler when the pressure in the furnace is higher than the set value and the flue draft loss is larger than the set value. It is equipped with a circuit.

Further, in order to achieve the above object, the present invention provides a furnace pressure gauge that measures and outputs the pressure inside the furnace, and a wind duct differential pressure gauge that measures and outputs the differential pressure between the air duct immediately after the forced air blower and the inside of the furnace. is installed, and the measurement values are taken from the furnace pressure gauge and the wind passage differential pressure gauge, respectively, and when the pressure in the furnace is lower than the set value and the wind passage draft loss is larger than the set value, the boiler is stopped. It is equipped with a circuit.

Furthermore, in order to achieve the above object, the present invention provides a secondary air flow meter that measures and outputs the flow rate of secondary air in a wind duct, and a 0! A flue gas 0□ meter that measures and outputs the amount of flue gas is installed, and the measured values are taken from the secondary air flow meter and the flue gas 02 meter, respectively, and the secondary air flow rate is less than the set value and the flue gas is The boiler is equipped with a circuit for determining whether the measured value is correct or not, which stops the boiler when the 02 amount is less than the set value.

[Effect]

In the invention comprising a brackish water level detecting means, a water supply flow rate transmitter, a steam flow rate transmitter, a subtracter, and a circuit for determining correctness of a measured value, the brackish water level in the brackish water brain is determined by the brackish water level detecting means. and sends the measured value to the correct/incorrect judgment circuit.

On the other hand, the water supply flow rate transmitter measures the water supply flow rate to the brackish water network, and sends the measured value to the subtractor.

On the other hand, the amount of steam generated from the brackish water network is measured by the steam flow rate transmitter, and the measured value is also sent to the subtractor.

The subtractor takes in the measured values from the feed water flow rate transmitter and the steam flow rate transmitter, subtracts the feed water flow rate and the amount of generated steam, obtains a deviation value, and processes the deviation value in a correctness determination circuit. .

The correct/incorrect judgment circuit takes in the measured values from the brackish water level detection means and the subtracter, respectively, and when the brackish water level is higher or lower than the set value and the deviation value between the water supply flow rate and the generated steam amount is larger than the set value, Boiler operation is determined to be dangerous and the boiler is stopped.

By the way, the brackish water level detection means are installed at least at both ends of the brackish water network in the axial direction, and if either of the brackish water level detection means at both ends of the axial direction indicates a high or low brackish water level, it is determined that the brackish water level is being measured correctly. It can be determined that

However, if only one of the brackish water level detection means at both ends in the axial direction indicates a high or low brackish water level, it is impossible to determine which one is correct. At this time, in the present invention, the deviation value between the amount of water supply and the amount of generated steam is determined by the correctness determination circuit for the measured value, and the deviation value is compared with a set value. If this holds true, it is determined that the brackish water level detecting means that indicates the high or low brackish water level is operating correctly, and that the other brackish water level detecting means are not operating correctly. Then, the correct/incorrect judgment circuit stops the operation of the boiler based on the indication of high or low brackish water level output from the brackish water level detecting means which is operating correctly.

This makes it possible to prevent erroneous stoppage and dangerous operation of the boiler by dealing with a failure of the entire brackish water level detecting means including mechanical and electrical elements of the equipment constituting the brackish water level detecting means.

Next, the furnace pressure gauge and flue differential pressure in the present invention.

In the invention, the pressure in the furnace is measured by the furnace pressure gauge, and the measured value is sent to the correctness determination circuit.

Further, the differential pressure between the furnace and the flue after the induced draft fan is measured by the flue differential pressure gauge, and the measured value is processed by the correctness determination circuit.

The circuit for determining whether the measured values are correct or incorrect takes in the measured values from the furnace pressure gauge and the flue differential pressure gauge, compares the pressure inside the furnace with a set value, and further compares the pressure between the furnace and the flue after the induced draft fan. Compare the flue draft loss found from the differential pressure with the set value. Then, when the pressure in the furnace is higher than the set value (and the flue draft loss is larger than the set value), the correct/incorrect judgment circuit determines that there is an abnormality and stops the operation of the boiler.

By the way, the furnace pressure gauge may indicate an abnormally high pressure inside the furnace due to an internal mechanical or electrical failure.

Furthermore, when the pressure inside the furnace becomes abnormally high, it is often the case that the damper between the furnace and the chimney is fully closed, or that the air heater is clogged.

Therefore, in the present invention, in addition to the pressure in the furnace, the flue draft loss is monitored, and if the pressure in the furnace is higher than the set value and the flue draft loss is greater than the set value, the boiler Since we are trying to stop the operation of
It is possible to prevent erroneous boiler stoppages and dangerous operation by dealing with failures of the entire measurement system, including the mechanical and electrical elements of the measuring equipment, such as failures in the furnace pressure gauge and clogging of the air heater.

Next, the furnace pressure gauge and the airway differential pressure gauge in the present invention,
In the present invention, the pressure inside the furnace is measured by the furnace pressure gauge, and the measured value is sent to the correct/incorrect judgment circuit.

Further, the airway differential pressure gauge measures the differential pressure between the airway immediately after the forced air blower and the inside of the furnace, and the measured value is processed by a correctness determination circuit.

The circuit for determining whether the measured values are correct or incorrect takes in the measured values from the furnace pressure gauge and the air passage differential pressure gauge, compares the pressure inside the furnace with a set value, and further compares the pressure between the air passage immediately after the forced air blower and the inside of the furnace. Compare the air passage draft loss obtained from the differential pressure with the set value. The correct/incorrect judgment circuit stops the operation of the boiler when the pressure in the furnace is lower than the set value and the airway draft loss is larger than the set value.

By the way, the furnace pressure gauge may indicate an abnormally low pressure inside the furnace due to an internal mechanical or electrical failure.

On the other hand, in a boiler having an induced draft fan, if the draft loss increases abnormally between the forced draft fan and the furnace, the pressure in the furnace will decrease abnormally.

Therefore, in the present invention, in addition to the pressure inside the furnace, the wind passage draft loss is monitored, and if the pressure inside the furnace is lower than the set value and the wind passage draft loss is greater than the set value, the boiler Since we are trying to stop the operation of
By dealing with failures in the entire measurement system, including mechanical and electrical elements such as the furnace pressure gauge and its peripheral equipment, it is possible to prevent erroneous boiler stoppages and dangerous operation.

Furthermore, the secondary air flow meter in the present invention and the flue gas 0
In the invention comprising two meters and a circuit for determining whether the measured value is correct or incorrect, the secondary air flow meter measures the flow rate of the secondary air in the wind duct, and the measured value is sent to the correct or incorrect judgment circuit.

In addition, the flue gas 0□ meter measures the 0 of the gas passing through the flue.
Two quantities are measured, and the measured values are processed by the correctness determination circuit.

The measurement value determination circuit takes in the measurement values from the secondary air flow meter and the flue gas 0□ meter, compares the secondary air flow rate in the wind duct with the set value, and determines the flue gas. 0□Compare the amount and set value. The correctness determination circuit stops the operation of the boiler when the secondary air flow rate is less than the set value and the amount of flue gas is less than the set value.

If the mechanical or electrical mechanism of the secondary air flow meter fails, the measured secondary air flow rate will be abnormally higher or lower than the set value.

Additionally, when the secondary air flow rate decreases below a predetermined set value, the 02 amount of flue gas decreases.

Therefore, in the present invention, the secondary air flow rate is measured using a secondary air flow meter, and the amount of O2 in the flue gas is monitored.
The operation of the boiler is stopped on condition that the secondary air flow rate is less than the set value and the 0□ amount of flue gas is less than the set value.

As a result, if the entire measurement system including the mechanical and electrical elements of the secondary air flow meter malfunctions, or if the secondary air flow rate decreases for some reason, it can be dealt with all at once, and the boiler can be stopped erroneously. It becomes possible to prevent dangerous driving.

〔Example〕

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

1 and 2 show an embodiment of the present invention,
FIG. 1 is a block diagram showing the arrangement of a boiler and measuring instruments installed around it, and FIG. 2 is a system diagram showing an embodiment of a circuit for determining whether a measured value is correct or incorrect.

The boiler shown in FIG. 1 includes a water wall 2, a brackish water barrel 3, a superheater 4, a water supply control system, and a circuit 26 for determining whether the measured value regarding the brackish water level is correct or incorrect.

As shown in FIG. 1, the water supply control system includes a water supply flow rate transmitter 1, a steam flow rate transmitter 5, a detection pipe 23-1.232 inserted into one side of the brackish water barrel 3, and the other side. Detection piping 23-3.23-4 inserted into the brackish water barrel 3, the brackish water level transmitter 7 provided across the detection piping 23-1.23-2 on one side of the brackish water barrel 3, and the other side of the brackish water barrel 3. A brackish water level transmitter 18 provided across the detection pipes 23-3 and 23-4 on the side, and a brackish water level high monitor switch 12 and a brackish water level low monitor switch 13 connected to the one brackish water level transmitter 7. and a brackish water level high monitor switch 1 connected to the other brackish water level transmitter 18.
9, a low brackish water level monitor switch 20, a water supply controller 21, and a water supply control valve 22.

In the feed water control system, the feed water flow rate is measured by the feed water flow rate transmitter 1, the measured value is sent to the feed water controller 21, the generated steam flow rate is measured by the steam flow rate transmitter 5, and the measured value is also sent to the feed water controller 21. Send it to 21. The water supply controller 21 takes in the measured values from the water supply flow rate transmitter H1 and the steam flow rate transmitter 5, calculates the current level of brackish water in the brackish water cylinder 3, and controls the water supply to keep the brackish water level constant. Control valve 22. On the other hand, brackish water level transmitter 7.1
8 monitors the actual brackish water level, and when the brackish water level is higher than the set value, the brackish water level high monitor switch 12.1
9 operates, and the detection result of high brackish water level is sent to the water supply controller 21.
send to. Further, when the brackish water level becomes lower than the set value, the brackish water level low monitor switch 13.20 is operated, and the detection result of the brackish water level low is sent to the water supply controller 21. The water supply controller 21 includes the brackish water level high monitor switch 1
2.19 or brackish water level low monitor switch 13.20
The water supply control valve 22 is subjected to feed hack control so that the actual brackish water level becomes the target value.

In addition, in Fig. 1, 8.9 is the detection pipe 23-1.23-2.
10.11 is a transmitter blow valve provided in detection pipe 23-1.23-2, 14
．． 15 is a transmitter artificial valve provided in the detection pipe 23-3.23-4, and 16.17 is a transmitter blow valve provided in the detection pipe 23-3.23-4.

As shown in FIGS. 1 and 2, the measurement value correctness determination circuit 26 includes a feed water flow rate transmitter 1 and a steam flow rate transmitter 5.
, a brackish water level detection means having a brackish water level transmitter 7 on one side, a brackish water level high monitor switch 12 and a brackish water level low monitor switch 13, and a brackish water level transmitter 18 on the other side.
a brackish water level detection means having a brackish water level high monitor switch 19 and a brackish water level low monitor switch 20, an or gate 24 connected to the brackish water level high monitor switch 12.19, and a brackish water level low monitor switch 13.20. In the boiler having the or gate 25,
a subtracter 6 connected to the water supply flow rate transmitter 1 and the steam flow rate transmitter 5; an AND gate 27 connected to the subtractor 6 and one OR gate 24; and an AND gate 27 connected to the subtractor 6 and the other OR gate 25. The AND date 28 and the OR gate 29 are connected to both the AND gates 27 and 28.

In the measurement value correctness determination circuit 26, the water supply flow rate transmitter 1
The feed water flow rate measured by the steam flow rate transmitter 5 is sent to the subtractor 6, and the generated steam flow rate measured by the steam flow rate transmitter 5 is also sent to the subtractor 6.

The subtractor 6 takes in the measured values from the feed water flow rate transmitter 1 and the steam flow rate transmitter 5, subtracts the generated steam flow rate from the feed water flow rate, calculates the deviation value regarding the brackish water level, and compares the obtained deviation value with the previously determined deviation value. Compare with the determined set value, and if the deviation value is greater than the set value, AND gate 27
．． A signal is output to 28. Note that the deviation value obtained from the feed water flow rate and the generated steam flow rate has slight fluctuations, that is, about 3 to 5%, even during normal operation, so the set value to be compared with the deviation value is , confirm the amount of deviation during actual operation and decide.

One of the AND gates 27 outputs an output from one of the OR gates 24 when at least one of the high brackish water level monitor switches 12 and 19 detects a high brackish water level, and an output from the subtractor 6 when the deviation value is large. When inputted with an output transmitted from a remote control, a signal is outputted to the oak host 29. The other AND gate 28 outputs an output from the other OR gate 25 when at least one of the brackish water level low monitor switches 13 and 20 detects the brackish water level low, and a subtracter 6 when the deviation value is large. When the output transmitted from the OR gate 29 is input, a signal is output to the OR gate 29.

When the OR gate 29 receives an output from at least one of the AND gates 27 and 28, it outputs a signal, and the signal stops the operation of the boiler.

In this way, the measurement value correctness judgment circuit 26 monitors not only the high or low brackish water level but also the deviation value between the feed water flow rate and the generated steam amount, and determines whether the brackish water level is higher or lower than the set value and the feed water flow rate is low. The boiler operation is stopped on the condition that the deviation value of the amount of steam generated is larger than the set value, so if the detection piping 23-1 to 23-4 is clogged or if there is brackish water The brackish water level detection means including the level transmitter 7.18, the brackish water level high monitor switch 12.19, and the brackish water level low monitor switch 13.20, and mechanical and electrical elements such as peripheral equipment are malfunctioning and the brackish water level is not detected. Even in the case of erroneous measurements, it is possible to prevent erroneous boiler stoppage and dangerous operation.

Next, Figure 3 is a block diagram showing the boiler furnace, the air blowing system to the furnace, the flue system from the furnace to the chimney, and the arrangement of equipment attached to these, Figures 4, 5, and FIG. 6 is a system diagram showing an embodiment of a circuit for determining whether the measured value is correct or incorrect.

The boiler shown in FIG. 3 includes a furnace 30, a wind duct 31,
It includes a flue 32 and a chimney 33.

The air passage 3H2 is a forced air blower (FORCEDDRAF).
A T FAN) 34, a damper 35, 36 disposed on the outlet side, and an air heater 37 disposed between the damper 36 and the furnace 30 are provided.

The flue 32 includes an air heater 38 and an induced draft fan (I).
ND (JCCED DRAFT FAN) 39 and
This person is provided with a damper 40, 41 located on the exit side.

Further, the furnace 30 is provided with furnace pressure gauges 42 and 43.

Furthermore, the air heater 37 in the air passage 31 and the furnace 3
A secondary air flow meter 44, 45 is provided between the forced air blower 34 and the damper 36, and an airway differential pressure gauge 47 is provided between the forced air blower 34 and the damper 36, and across the furnace 30.

Furthermore, a flue gas 0□ total 46 is provided between the furnace 30 and the air heater 38 in the flue 32,
Across the furnace 30, between the damper 41 and the chimney 33,
A flue differential pressure gauge 48 is provided.

Next, a measurement value correctness determination circuit 49 shown in FIG. 4 targets the pressure in the furnace and the flue draft loss, and is connected to the flue differential pressure gauge 48 and the furnace pressure gauges 42 and 43. or gate 50, the flue differential pressure gauge 48, and or gate 5.
0 and an AND gate 51 connected to 0.

The furnace pressure gauges 42 and 43 measure the pressure inside the furnace 30, compare the measured value with a set value, and send a signal to the or gate 50 when the pressure inside the furnace 30 becomes higher than the set value. Output.

In the measurement value correctness determination circuit 49, the furnace pressure gauge 4
When at least one of 2.43 detects an abnormally high furnace pressure, the OR gate 50 outputs a signal to the AND gate 51.

Additionally, the flue differential pressure gauge 48 measures the differential pressure between the pressure in the furnace 30 and the pressure in the flue 32 in front of the chimney 33, compares the measured value with a set value, and determines that the differential pressure is lower than the set value. When it is high, a signal is output to the AND gate 51 indicating that the flue draft loss is excessive.

The AND gate 5 outputs an output from the OR gate 50 when at least one of the furnace pressure gauges 42 and 43 detects abnormally high furnace pressure, and when the flue differential pressure gauge 48 detects excessive flue draft loss. When the output to be transmitted is input, a signal is output and the boiler operation is stopped by that signal.

Generally, abnormally high furnace pressure occurs between the furnace 30 and the chimney 33 due to the dampers 40, 41 being fully closed, or the air amount adjustment handle 38 being clogged.

Therefore, in addition to the abnormally high furnace pressure, the measurement value correctness determination circuit 49 monitors the flue draft loss and detects when the pressure inside the furnace is higher than the set value and the flue draft loss is higher than the set value. The boiler operation is stopped under the condition that the furnace pressure gauge 42, 43 is malfunctioning, the damper 40, 41 is fully closed during the boiler operation, or the air volume adjustment handle 38 is closed. It is possible to prevent erroneous boiler stoppage and dangerous operation due to clogging.

Next, the measurement value correctness judgment circuit 52 shown in FIG. A wind passage differential pressure gauge 47 provided across the
an or gate 53 connected to the furnace pressure gauge 42, 43;
It is configured to include the air passage differential pressure gauge 47 and an AND gate 54 connected to the OR gate 53.

Here, the furnace pressure gauges 42 and 43 measure the pressure inside the furnace 30, compare the measured value with a set value, and measure the pressure inside the furnace 30.
When the internal pressure becomes lower than the set value, the OR gate 53
Outputs a signal to.

In the measurement value correctness determination circuit 52, the furnace pressure gauge 4
2. When at least one of 43 detects an abnormal furnace pressure paper, a signal is output from the OR gate 53 to the AND gate 54.

The air passage differential pressure gauge 47 measures the differential pressure between the pressure immediately after the forced air blower 34 and the pressure inside the furnace 30, compares the measured value with a set value, and when the differential pressure is lower than the set value, the air passage A signal is output to the AND gate 54 indicating that the road draft loss is excessive.

The AND gate 54 outputs an output when at least one of the furnace pressure gauges 42 and 43 detects an abnormal furnace pressure, and an output when the wind passage differential pressure gauge 47 detects excessive draft loss. When input, a signal is output and the boiler operation is stopped by that signal.

By the way, as shown in FIG. 3, in a boiler having an induced draft fan 39, if the draft loss increases abnormally between the forced draft fan 34 and the furnace 30, the pressure inside the furnace 30 decreases abnormally.

Therefore, in addition to the furnace pressure abnormality paper, the measurement value correctness judgment circuit 52 monitors the wind passage draft loss and detects that the pressure in the furnace is lower than the set value and the wind passage draft loss is larger than the set value. The condition is that the boiler operation must be stopped. This allows us to collectively deal with abnormal furnace pressure caused by excessive draft loss due to failure of the furnace pressure gauge 42, 43, clogging of the air heater 37, fully closing of the damper 35, 36 during boiler operation, etc. This can prevent erroneous boiler stoppages and dangerous operation.

Further, the measurement value correctness determination circuit 55 shown in FIG. 6 targets the secondary air flow rate and the amount of 02 in the flue gas, and includes a flue gas 0□ meter 46 and a secondary air flow rate meter 44. 45, and an ant gate 157 connected to the flue gas 02 total 46 and the or gate 56.

The secondary air flow meter 44, 45 measures the flow rate of secondary air sent into the furnace 30, and outputs an output to the OR gate 56 when the measured value is less than a set value.

The flue gas 02 meter 46 measures the amount of flue gas passing through the flue 32, and outputs a signal to the AND gate 57 when the measured value is less than a set value.

The OR gate 56 outputs a signal to the AND gate 57 when receiving an output from at least one of the secondary air flow meters 44, 45.

The AND gate 57 outputs a signal when the output transmitted from the flue gas 02 meter 46 and the output transmitted from the OR gate 56 are input, and the operation of the boiler is stopped by the signal.

By the way, when the flow rate of secondary air sent into the furnace 30 decreases, the amount of flue gas 02 decreases.

Therefore, in addition to the secondary air flow rate, the second measurement value correctness judgment circuit 55 monitors the 00° amount in the flue gas, and checks if the secondary air flow rate is less than the set value and the 02 amount of the flue gas is The boiler operation is stopped on condition that the amount is less than the set value.

This allows you to take action all at once if either of the secondary air flow meters 44 or 45 malfunctions and indicates a low secondary air flow rate, or if the secondary air flow rate actually starts to decrease for some reason. This makes it possible to prevent erroneous boiler stoppages and dangerous operation.

〔Effect of the invention〕

According to the invention described in claim 1 of the present invention described above, the brackish water level detection means measures and outputs the brackish water level in the brackish water brain, and the water supply flow rate transmitter measures and outputs the water supply flow rate to the brackish water network. , an air flow rate transmitter that measures and outputs the amount of steam generated from the brackish water network, and a subtractor that calculates and outputs a deviation value between the feed water flow rate and the amount of generated steam, and the brackish water level detection means. Equipped with a circuit that determines whether the measured values are correct or incorrect and stops the boiler when the brackish water level is higher or lower than the set value and the deviation value between the feed water flow rate and the amount of steam generated is larger than the set value. The deviation value between the amount of water supplied and the amount of steam generated is determined by the correctness judgment circuit for the measured value, and the deviation value is compared with the set value. If so, it is determined that the brackish water level detecting means that indicates the high or low brackish water level is operating correctly, the other brackish water level detecting means are not operating correctly, and the correct/incorrect judgment circuit detects the brackish water level detecting that the brackish water level is operating correctly. Since the operation of the boiler is stopped based on the indication of high or low brackish water level output from the means, the brackish water level detecting means includes mechanical and electrical elements of the equipment constituting the brackish water level detecting means. This has the effect of preventing erroneous boiler stoppages and dangerous operation by dealing with overall failures.

According to the second aspect of the present invention, the furnace pressure gauge measures and outputs the pressure inside the furnace, and the furnace pressure gauge measures and outputs the differential pressure between the furnace and the flue after the induced draft fan. A pressure differential pressure gauge is provided, and the measured values are taken from the furnace pressure gauge and the flue differential pressure gauge, respectively, and when the pressure in the furnace is higher than the set value and the flue draft loss is larger than the set value, the measured value is used to stop the boiler. It is equipped with a correct/false judgment circuit that monitors the flue draft loss in addition to the pressure inside the furnace, and detects when the pressure inside the furnace is higher than the set value and the flue draft loss is larger than the set value. As a condition, the boiler operation must be stopped, so we can deal with failures of the entire measurement system, including mechanical and electrical elements of the measurement equipment, such as failures of the furnace pressure gauge and clogging of the air volume adjustment handle. Due to this, the boiler accidentally stopped,
This has the effect of preventing dangerous driving.

Furthermore, according to the third aspect of the present invention, there is provided a furnace pressure gauge that measures and outputs the pressure inside the furnace, and a furnace pressure gauge that measures and outputs the differential pressure between the air duct immediately after the forced air blower and the inside of the furnace. A differential pressure gauge is provided, and the measured values are taken from the furnace pressure gauge and the wind channel differential pressure gauge, respectively, and the measured value is used to stop the boiler when the pressure in the furnace is lower than a set value and the wind channel draft cost is larger than the set value. In addition to the pressure inside the furnace, it also monitors the draft loss in the air passage, and detects when the pressure inside the furnace is lower than the set value and the draft loss in the air passage is greater than the set value. As a condition, boiler operation must be stopped, so failures in the entire measurement system, including mechanical and electrical elements such as the furnace pressure gauge and its peripheral equipment, must be dealt with to prevent erroneous boiler stoppages and dangerous operation. There is a preventive effect.

According to the invention described in claim 4 of the present invention, there is provided a secondary air flow meter that measures and outputs the flow rate of secondary air in the wind duct, and a secondary air flowmeter that measures and outputs the amount of 0□ of flue gas. A road gas 02 meter is provided, and the measured values are taken from the secondary air flow meter and the flue gas 02 meter, respectively, and when the secondary air flow rate is less than the set value and the amount of flue gas 02 is less than the set value, Equipped with a circuit that determines whether the measured value is correct or incorrect to stop the boiler.
In addition to the secondary air flow rate sent to the furnace, the amount of 02 in the flue gas is monitored, and if the secondary air flow rate is less than the set value,
In addition, the boiler operation is stopped when the amount of flue gas becomes less than the set value, so the entire measurement system including mechanical and electrical elements such as the secondary air flow meter is This has the effect of being able to take immediate action in the event of a breakdown or a decrease in the secondary air flow rate due to some reason, preventing erroneous boiler stoppages, and dangerous operation.

In addition, the inventions according to claims 1 to 4 of the present invention do not provide a failure diagnosis means to deal with troubles of individual devices, but are designed to deal with troubles of the measuring devices and peripheral devices all at once. Therefore, it is possible to avoid complication of the system while exhibiting the above-mentioned effects.

[Brief explanation of drawings]

Figures 1 and 2 show one embodiment of the present invention. Figure 1 is a block diagram showing the arrangement of a boiler and measuring equipment installed around it, and Figure 2 is a block diagram showing the arrangement of measurement equipment installed around the boiler. Figure 3 is a system diagram showing an example of the correct/incorrect judgment circuit, and is a block diagram showing the boiler furnace, the air blowing system to the furnace, the flue system from the furnace to the chimney, and the arrangement of equipment attached to these. Figure, 4th
5 and 6 are system diagrams each showing an embodiment of a circuit for determining whether a measured value is correct or incorrect, and FIG. 7 is a block diagram showing a conventional wave 4Jj. 1... Water supply flow rate transmitter, 3... Brackish water network, 5... Brown air flow rate transmitter, 6... Subtractor, 7.1... Brackish water level transmitter, 12.19... Brackish water level high monitor switch, 13.20...Brackish water level low monitor switch, 2
31 to 23-4...Detection piping, 26...Correctness determination circuit for measured value, 27.28...And gate, 29...
・Or gate, 30... Furnace, 31... Wind path, 32
... Flue, 33... Chimney, 34... Forced blower,
35.36... Damper, 37.38... Air heater, 39... Induced draft fan, 40.41... Damper, 4
2.43... Furnace pressure gauge, 44.45... Secondary air flow meter, 46... Flue gas 0□ meter, 47... Air passage differential pressure gauge, 48... Flue differential pressure gauge , 49... Measured value correctness judgment circuit, 50... OR gate, 51... AND gate, 52... Measured value correctness judgment circuit, 53... OR date, 54... AND gate, 55 . . . Measurement value correctness judgment circuit, 56 . . . OR gate, 57 . . . AND gate.

Claims (4)

[Claims] (1) A brackish water level detection means that measures and outputs the brackish water level in the brackish water shell; a water supply flow rate transmitter that measures and outputs the water supply flow rate to the brackish water shell; and a brackish water flow rate transmitter that measures the amount of steam generated from the brackish water shell; A steam flow rate transmitter that outputs and a subtracter that calculates and outputs the deviation value between the feed water flow rate and the generated steam amount are provided, and the measured values are taken from the brackish water level detection means and the subtracter, respectively, and the brackish water level is set to the set value. 1. A safe operation device for a boiler, comprising a measurement value determination circuit that stops the boiler when the deviation value between the feed water flow rate and the amount of steam generated is higher or lower than a set value. (2) A furnace pressure gauge that measures and outputs the pressure inside the furnace;
A flue differential pressure gauge is installed to measure and output the differential pressure between the furnace and the flue after the induced draft fan, and the measured values are taken from the furnace pressure gauge and the flue differential pressure gauge, respectively, and the pressure in the furnace is adjusted to the set value. 1. A safe operation device for a boiler, characterized in that it is equipped with a measurement value correctness determination circuit that stops the boiler when the flue draft loss is greater than a set value. (3) A furnace pressure gauge that measures and outputs the pressure inside the furnace;
A wind passage differential pressure gauge is installed to measure and output the differential pressure between the air passage immediately after the forced air blower and the inside of the furnace, and the measured values are taken from the furnace pressure gauge and the wind passage differential pressure gauge, respectively, and the pressure inside the furnace is determined to be the set value. 1. A safe operation device for a boiler, characterized in that it is equipped with a measurement value correctness judgment circuit that stops the boiler when the windway draft loss is lower than a set value and larger than a set value. (4) A secondary air flow meter that measures and outputs the flow rate of secondary air in the wind duct and a flue gas O_2 meter that measures and outputs the amount of O_2 in the flue gas are provided, and the secondary air flow rate is Equipped with a circuit that determines whether the measured values are correct or incorrect, which takes in the measured values from the meter and the flue gas O_2 meter, and stops the boiler when the secondary air flow rate is less than the set value and the amount of O_2 in the flue gas is less than the set value. A safe operation device for a boiler characterized by the following.