JPS631485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for injecting a can cleaning agent in order to prevent scale adhesion on water pipes in a boiler system, and in particular, it measures the steam load factor of the boiler system over a predetermined period of time, and When the steam load rate in the tank is low, which is lower than the scheduled standard steam load rate, the basic amount of can cleaning agent is added to the can water into which the regular amount of can cleaning agent has been added in advance. This invention relates to a basic injection control device for can cleaning agent in boiler systems.

Generally, when a boiler system is operated for a long time, the canned water becomes concentrated, so the concentration of impurities such as calcium, magnesium, and silica contained in the canned water increases, and these impurities precipitate and adhere to the inner surface of the water pipes and grow into scale. It is. Since scale is a poor conductor of heat, it is known that scale adhesion not only reduces the efficiency of heat exchange in the boiler system, but also causes water pipes to reach high temperatures, eventually leading to burnout. There is.

In order to deal with such inconveniences, it is known to continuously inject a constant amount of can cleaning agent into the water supply during operation of the boiler system to prevent scale adhesion. A predetermined amount of can cleaning agent is injected into the water supply itself in advance, or a predetermined amount of can cleaning agent is put into the can water in conjunction with a water supply pump.

In addition, in order to prevent scale adhesion in the boiler water pipes and to minimize corrosion of the boiler system, it is necessary to adjust the pH concentration of canned water in the boiler system.
It is known from experience that it is sufficient to set it to 11.0 to 11.8.

Therefore, in consideration of the fact that canned water in the boiler system gradually becomes concentrated as the boiler system operates, and that the rate of concentration depends on the steam load rate in the boiler system, we decided to pH concentration is PH7.0
The regular injection amount of can cleaning agent is determined to be approximately 7.5.

That is, if the amount of can cleaning agent regularly added is excessive, the pH concentration of the feed water increases and the feed water becomes alkaline, and when the boiler is operated at a high steam load rate, the can water tends to become concentrated. In such a concentrated state of canned water, the concentration of impurities such as dissolved solids contained in the canned water increases and bubbles are generated on the surface of the canned water, and these bubbles leave the air-water interface and enter the steam. It is known that contamination can cause carryover, which can damage related equipment such as valves connected to the boiler system. In order to prevent such carryover, it is necessary to frequently blow the canned water, but generally the blowing must be performed with the boiler system stopped, making boiler maintenance management complicated.

On the other hand, if the constant amount of can cleaning agent added is too small, the pH concentration of the feed water will be low and the feed water will become neutral, and if the boiler is operated for a long time at a low steam load rate, the concentration of can water will not be promoted. , the pH concentration of the canned water remains low for a long time and does not reach the desired pH of 11.0 to 11.8. As a result, corrosion of the water pipes is accelerated.

Therefore, at various steam load rates, the appropriate PH
In order to improve the probability that the boiler system can be operated between 11.0 and 11.8, the steady input amount is set to a small value, and the operator monitors whether the boiler is being operated at a low steam load rate. The basic amount of can cleaning agent is added manually to the regular amount, so that the pH concentration of can water reaches the appropriate pH faster than before during low steam loads. During high steam loads, measures are taken to prevent can water from becoming concentrated immediately.

However, if it is left to the operator to judge whether or not the boiler operating state is at a low steam load rate, the judgment is so difficult that it requires skill, resulting in inaccuracy, and the basic charging operation is extremely complicated, resulting in negligence. easy to be Therefore, if the boiler is operated at a low steam load rate but no basic injection is performed, corrosion of the boiler system will accelerate, and conversely, if the basic injection is performed while the boiler is operated at a high steam load rate, The drawback is that the canned water becomes concentrated more quickly, resulting in carry over.

The purpose of the present invention is to calculate the steam load rate of a boiler during a specific measurement period, in view of the problems of the difficulty in determining whether or not the basic injection of can cleaning agent is necessary and the complexity of the basic injection operation based on the above-mentioned conventional technology. In addition to measuring and determining whether basic input is necessary based on the load rate,
It is an object of the present invention to provide a control device for controlling the basic injection of can cleaning agent in a boiler system, which is capable of injecting the basic injection amount of can cleaning agent into a water pipe when it is determined that basic injection is necessary.

The configuration of the present invention in accordance with the above object is to measure the steam load factor of the boiler by monitoring the operating state of the heating device during a specific measurement period, and to determine the magnitude relationship between the preset reference steam load factor and the steam load factor. The system is characterized in that when it is determined that the steam load rate is low, the basic amount of can cleaning agent is automatically poured into the water pipe.

Now, before explaining the subsequent embodiments of the present invention, the structure and operation of a typical small boiler system to which the structure of the present invention can be attached will be explained as follows.

FIG. 1A is a block explanatory diagram showing the configuration of such a boiler system, and a cross section of the boiler 1 is shown.

FIG. 1B is a sectional view taken along line AA in FIG. 1A.

In the figure, inside a boiler 1, a large number of water pipes 1b are installed along the inner peripheral surface of a wall 1a.
b consists of a hollow cylindrical body, its lower end communicates with the annular lower header 1c (water chamber), and its upper end communicates with the annular upper header 1d (steam chamber), respectively. Canned water is stored in the lower part of 1c and water pipe 1b.

A combustion chamber 1e is formed in the center of the boiler 1 surrounded by water pipes 1b. An air passage 1h communicating with a blower 1g driven by an electric motor 1f is provided in the upper part of the boiler 1, and a nozzle rod 1i is installed in the air passage 1h.
and an electrode rod 1j is vertically installed.

The lower end of the combustion chamber 1e communicates with the flue 1k through the hollow portions of a large number of water pipes 1b. From the upper header 1d, a communication pipe 1l extends outside the wall 1a and communicates with the lower header 1c.

A water level gauge 1m and a water level detector 2 for visually displaying the canned water level are installed in the middle of the communication pipe 1l. A water supply control section 3 is connected to the water level detection section 2 , and an output terminal thereof is connected to an electric motor 4 a that drives a water supply pump 4 . An inlet pipe of the water supply pump 4 communicates with a water source (not shown), and a discharge pipe thereof communicates with the lower header 1c.

Furthermore, a vapor pressure measuring section 5 is provided at the upper part of the communication pipe 1l.
is connected, and its output terminal is connected to the combustion control section 6. From the combustion control section 6, control signal lines 6a' to
6c' extends and is connected to each of the electric motor 1f, electrode rod 1j, and fuel pump 6d'. fuel pump 6
The inlet pipe d' communicates with a fuel tank (not shown), and the discharge pipe thereof communicates with the nozzle rod 1i. A blow pipe 1n extends from the lower header 1c and communicates with a drainage channel (not shown) via a blower stock 1p, and a steam pipe 1q extends from the upper header 1d and communicates with a desired steam load (not shown).

In the configuration of the boiler system described above, when generating steam, the electric motor 1f drives the blower 1g to forcefully feed air into the air passage 1h while applying a high voltage to the electrode rod 1j to generate steam from the tip of the nozzle rod 1i. The injected fuel is ignited and combusted within the combustion chamber 1e. High-temperature combustion gas generated by such combustion enters the hollow part of the water pipe 1b from the lower end of the combustion chamber 1e, passes through it, reaches the flue 1k, and is exhausted. During this time, heat exchange takes place and the canned water in the water pipe 1b is heated and turned into steam, which is then transferred to the upper header 1.
d is collected and stored, and supplied to the steam load through steam pipe 1q.

Regarding combustion control, the upper header 1d
The steam pressure inside the upper header 1d is extracted through the communication pipe 1l and supplied to the steam pressure measuring section 5, and the steam pressure measuring section 5 detects that the steam pressure inside the upper header 1d has reached a preset lower limit steam pressure. Sometimes, the lower limit vapor pressure signal is similarly sent to the combustion control section 6 when it is detected that the upper limit vapor pressure has been reached.

When the steam pressure in the upper header 1d drops due to continued consumption of steam and a lower limit steam pressure signal is received from the steam pressure measuring section 5, the combustion control section 6 starts the electric motor 1f via the control signal line 6a'. Let me, blower 1
After purging the air passage 1h with air by g, a high voltage is applied to the electrode rod 1j through the control signal line 6b', and at the same time, the fuel pump 6 is applied through the control signal line 6c'.
d' is started to ignite the fuel injected from the nozzle rod 1i and start combustion. Further, when the steam generation continues and the steam pressure increases and the combustion control section 6 receives an upper limit steam pressure signal from the steam pressure measurement section 5, the fuel pump 6d' is stopped via the control signal line 6c', By cutting off the fuel supply, combustion is stopped, and after waiting for the combustion gas to be discharged, the electric motor 1f is stopped via the control signal line 6a', and the air blowing from the blower 1g is cut off.

By such intermittent control of combustion, the steam pressure in the upper header 1d can be maintained at a pressure value between the two pressure values preset as the upper and lower steam pressure limits.

In addition, in a simple device, the start/stop control of the electric motor 1f and the fuel pump 6d', and the application of high voltage to the electrode rod 1j may be performed simultaneously.

Furthermore, regarding water supply control, changes in the canned water level in the air-water interface in the communication pipe 1l, that is, in the water pipe 1b, are transmitted to the water level detection section 2, and the water level detection section 2 detects the canned water level set in advance. When it is detected that the lower limit water level has been reached, a lower limit water level signal is sent to the water supply control unit 3, and similarly, when it is detected that the upper limit water level has been reached, an upper limit water level signal is sent to the water supply control unit 3.

When the can water level in the water pipe drops due to steam consumption and a lower limit water level signal is received from the water level detection unit 2, the water supply control unit 3 starts the electric motor 4a and causes the water supply pump 4 to lower the water pipe 1b through the lower header 1c.
When the canned water level rises as the water supply continues and an upper limit water level signal is received from the water level detector 2, the electric motor 4a is stopped to cut off the water supply to the water pipe 1b.

Through such intermittent water supply control, the water level of the canned water in the water pipe 1b can be maintained at a water level between the upper and lower limit water levels preset.

The intermittent control of water supply and the intermittent control of combustion are performed separately and independently from each other.

Further, when blowing canned water, by opening the blowing tank 1p, part or all of the canned water in the lower header 1c and the water pipe 1b can be blown out through the drain pipe 1n.

In addition, blower 1g, air passage 1h, nozzle rod 1i,
The burner consisting of the electrode rod 1j is not limited to this, and if necessary, it is sufficient to heat the canned water in the water pipe 1b to generate steam, so generally an electric heater or the like is also used. Any heating device including the above may be used.

Similarly, the combustion control section 6 may also be a heating control section that turns on and off the heating device.

Next, the structure and operation of the embodiment of the present invention will be explained based on FIGS. 2 to 5 as follows.

FIG. 2 is a block diagram showing the respective configurations of a steam pressure detection section, a heating control section, a steam load factor measurement section, a steam load factor determination section, a measurement period signal section, and a can cleaning agent basic injection section in an embodiment of the present invention. In the figure, the first
Components denoted by the same reference numerals as those in the figures correspond to the components in FIG. 1, respectively.

The vapor pressure detection section 5 includes a pressure sensor 5a, first and second comparators 5b and 5c following the pressure sensor 5a,
It consists of potentiometers 5d and 5e that supply voltages respectively corresponding to the lower limit vapor pressure and the upper limit vapor pressure to each comparator.

The heating control section 6 has a first flip-flop 6b whose set terminal is connected to the first comparator 5b and whose reset terminal is connected to the second comparator 5c via the inverter 6a, and the positive phase of the flip-flop 6b. Driver 6 on the output terminal
A first relay 6d is connected to the first relay 6d via the first comparator 5b, and a monostable multivibrator 6e is connected to the first comparator 5b, and its set terminal is connected to the output terminal of the multivibrator 6e, and its reset terminal is connected to the inverter. The second flip-flop 6f is connected to the output terminal of the flip-flop 6a, and the second relay 6h is connected to the positive phase output terminal of the flip-flop 6f via a driver 6g.

Furthermore, a motor 1f, an electrode rod 1j, a fuel valve 6
Power supply lines 6a', 6b', and 6c' extending from d' are connected to a power source (not shown) through make contacts _r1 , _r1 ' of the first relay 6d, make contact _r2 of the second relay 6h, and start switch 1r, respectively. Connected. In addition, power is supplied to the water supply pump driving motor 4a through a switch 1r' that is interlocked with the start switch 1r, and the input terminal of a timer 7a, which will be described later, can be grounded through a switch 1r'' that is also interlocked with the start switch 1r. be made into

The measurement period signal section 7 includes a timer 7a whose input terminal is connected to the switch 1r'', a first monostable multivibrator 7b whose input terminal is connected to the output terminal of the timer 7a, and a first monostable multivibrator 7b whose input terminal is connected to the output terminal of the timer 7a. A second monostable multivibrator 7 connected to the positive phase output terminal of the first monostable multivibrator 7b
It consists of c.

The steam load factor measuring section 8 has a clock pulse oscillator 8a, three input terminals, a positive phase output terminal of the flip-flop 6f of the heating control section 6, a clock pulse oscillator 8a, and a timer 7a of the measurement period signal section 7.
AND gate 8 with the output terminals connected to each
b, the output terminal of the AND gate 8b is connected to its input terminal, and the measurement period signal section 7 is connected to the reset terminal.
A counter 8c is connected to the complementary output terminal of the second monostable multivibrator 7c, its input terminal is connected to the output terminal of the counter 8c, and the sample and hold terminal is connected to the first monostable multivibrator 7c. A digital-to-analog converter 8d is connected to the positive phase output terminal of the multivibrator 7b.

The steam load factor measuring section 8 includes a steam load factor determining section 9.
is followed by a comparator 9b, whose inverting input terminal is connected to the output terminal of the measuring section 8, and whose non-inverting input terminal is connected to the power supply via a potentiometer 9a, and one input. The comparator 9b is connected to the terminal, and the first monostable multivibrator 7b of the signal section 7 is connected to the other input terminal.
and a NAND gate 9c to which the positive-phase output terminal of is connected.

The steam load rate determination section 9 includes a can cleaning agent basic injection section 1.
Followed by 0. The can cleaning agent basic feeding section 10 includes a first monostable multivibrator 10a whose input terminal is connected to the output terminal of the NAND gate 9c of the steam load factor determination section 9, and a monostable multivibrator 10a.
A relay 10c is connected to the positive phase output terminal of the relay 10c via a driver 10b, and a make contact of the relay 10c
an electric motor 10d connected to the power supply via r ₁₀ ;
It consists of a can cleaning agent injection pump 10e driven by an electric motor 10d.

FIG. 3 shows the vapor pressure inside the communication pipe 1l, that is,
A temporal change A of the vapor pressure signal output by the pressure sensor 5a, an output signal B of the second comparator 5c,
The output signal C of the first comparator 5b and the "1" of the first flip-flop 6b in the heating control section 6
FIG. 6 is a waveform diagram showing a comparison between a "0" state D and a "1" and "0" state E of a second flip-flop 6f in the same section.

In the above configuration, the vapor pressure in the communication pipe 1l,
That is, when the steam pressure in the upper header 1d reaches the upper limit steam pressure and the steam pressure signal S1 output from the pressure sensor _5a reaches the upper limit set value H corresponding to the upper limit steam pressure, as shown in No. 3Aa. , the vapor pressure signal _S1 supplied to the second comparator 5c reaches the reference voltage corresponding to the upper limit set value H supplied from the power supply via the potentiometer 5e, so that
As shown in Bb, the output of the comparator 5c is inverted to "1" and supplies the upper limit vapor pressure signal _S2 , and in response to this inverted signal from "0" to "1", the inverter 6a is inverted to "1". An inverted signal from "0" to "0" is supplied to the reset terminal of the first flip-flop 6b to reset it as shown in FIG. 3Dc.

As a result, the positive phase output of the flip-flop 6b becomes "0", and the first relay 6d shifts to the de-energized state via the driver 6c, so that the contacts r ₁ ,
r ₁ ' is opened, the power supply through the power supply lines 6a' and 6b' is cut off, the blower 1g stops blowing air, and the electrode rod 1j stops spark discharge. At this time, the inverted signal from the inverter 6a is also supplied to the reset terminal of the second flip-flop 6f, resetting it as shown in FIG. 3 Ed.

As a result, the positive phase output of the flip-flop 6f becomes "0" and the second relay 6h also shifts to the de-energized state via the driver 6g, so the contact _r2 is opened and the power is supplied through the power supply line 6c'. supply is cut off,
Fuel valve 6d' is closed.

In this state, neither air blowing by the blower 1g nor ignition by spark discharge occurs, the fuel supply is cut off, and the burner is extinguished.

After the burner is extinguished, the steam pressure increases slightly due to thermal transient phenomena and then decreases as the boiler temperature decreases.
The vapor pressure signal S ₁ increases once as shown in FIG. 3Ae, and then decreases linearly as shown in FIG. 3Af.

As shown in FIG. 3Ah, when the vapor pressure signal _S1 crosses the upper limit set value H, the second comparator 5
The output signal of c is "1" as shown in Figure 3 Bi.
to "0".

When the vapor pressure signal S ₁ continues to fall and decreases to the lower limit set value _L as shown in FIG. The output of the comparator 5b reaches the reference voltage corresponding to the lower limit set value L supplied from the power supply via the third
As shown in Figure Cl, the lower limit vapor pressure signal _S3 is inverted to "0" and is supplied, and as shown in Figure 3Dm, the first flip-flop 6b is set and the first relay 6d is in an energized state. Then, the blower 1g is started to purge air into the air passage 1h.

As mentioned above, the inverted signal from the first comparator 5b when the blower 1g starts, that is, the lower limit vapor pressure signal _S3 , is also supplied to the monostable multivibrator 6c, triggering it, and causing a quasi-stable state. When the multivibrator 6e returns to a stable state, the second flip-flop 6f is set as shown in FIG. 3E.

Then, the second relay 6h becomes energized,
Contact r ₂ closes, supplying power source 6 to fuel valve 6d'.
Since power is supplied through c', the valve 6
d' opens, fuel is ejected from the fuel injection rod 1i,
The burner shifts to the combustion state.

In the above operation, as shown in FIG. 3E, the period during which the flip-flop 6f is set to "0" is the heating stop period _T2 , and furthermore, after the blower 1g starts, the fuel valve 6d' The period tp until it opens is a pre-purge period necessary to purge air inside the air passage 1h and reliably ignite the burner.

However, even during the pre-purge period tp, the vapor pressure signal _S1 decreases as shown in FIG. 3Ap, and by the time the burner shifts to the combustion state, the third
As shown in Figure Aq, it decreases to the minimum value LL, and then, when the burner starts combustion, it linearly increases as shown in Figure 3 Ar as the temperature of the boiler increases.

When the increasing vapor pressure signal _S1 reaches the lower limit set value L again as shown in FIG. 3A, as shown in FIG.
As shown by Ct, the output signal of the first comparator 5b is inverted to "1".

As the combustion state of the burner continues, the steam pressure continues to rise, and the steam pressure signal _S1 eventually reaches the upper limit set value H as shown in FIG. 3Av, and as shown in FIG.
It operates similarly to the above explanation with reference to c and d;
As shown in Figures b', c' and d', both the first and second flip-flops 6b and 6f are reset.

Therefore, in the above operation, during the period _T1 during which the flip-flop 6f is set to "1", the combustion chamber 1
This is the heating period during which combustion is occurring.

Therefore, in this type of boiler system, combustion is intermittent depending on the steam load, so
The steam load rate of the boiler can be detected by measuring the sum of the heating periods T ₁ or the sum of the heating stop periods T ₂ in a specific measurement period. Then, using the steam load rate detected in this way, the high steam load rate or low steam load rate is determined, and when it is determined that the steam load rate is low, the basic amount of can cleaning agent is added to the can water. It is an investment.

Referring to FIG. 4, the operations of the measurement period signal section 7, steam load rate measurement section 8, steam load rate determination section 9, and can cleaning agent basic injection section 10 will be described as follows.

As shown in FIG. 4Aa, when the start switch 1r'' linked to the start switch 1r is closed, the start command signal _S4 is supplied to the timer 7a, and the timer 7a starts timing.As shown in FIG. 4Bb As shown, when combustion in the boiler 1 starts and the heating device operating state signal _S5 from the heating control section 6 becomes "1", the clock pulse of the clock pulse oscillator 8a of the steam load measuring section 8 passes through the AND gate 8b. The counter 8c starts counting as shown in FIG. 4 Cc, and its contents increase over time as shown in FIG. 4 Cd.

Eventually, as shown in FIG. 4Be, when the heating device operating state signal _S5 becomes "0", the AND gate 8b is activated.
is closed, and the supply of clock pulses from the clock pulse oscillator 8a to the counter 8c is cut off.

Then, the counting operation of the counter 8c is stopped, and the contents of the counter 8c are temporarily stopped as shown in FIG. 3Cf. Next, as shown in Figure 4Bg,
When combustion in the boiler 1 is restarted and the heating device operating state signal _S5 becomes "1" again, the contents of the counter 8c increase over time from Ch in FIG. As shown in Bi, when the heating device operating state signal _S5 becomes "0", the counting operation of the counter 8c is stopped, and as shown in FIG. 4Cj, the contents of the counter 8c are temporarily stopped.

In this way, during the measurement period _T3 set in the timer 7a, the heating device operating state signal _S5 indicating the operating state of the heating device that causes combustion in the boiler is “ ₁ ”. A cumulative heating period ΣT ₁ is calculated.

Next, as shown in FIG. 4Ak, timer 7a
When the set measurement period _T3 ends and the output signal _S6 of the timer 7a becomes "0", the AND gate 8b closes and the clock pulse oscillator 8a outputs a signal from the counter 8.
The supply of clock pulses to clock 8c is cut off, and counting by counter 8c ends.

When the output signal S ₆ of the timer 7a becomes "0", the subsequent first monostable multivibrator _7b is triggered, and as shown in FIG. ' is output from its positive phase output terminal. In response to the rise of the sample and hold signal _S7 , the digital-to-analog converter 8d takes in the content of the cumulative heating period signal _S8 from the counter 8c and converts it into an analog voltage cumulative heating period signal _S8 '. The analog signal S ₈ ' is supplied to the steam load factor determining section 9.

The cumulative heating period signal S ₈ ' is supplied to the inverting input terminal of the comparator 9b, and the reference steam load factor preset by the potentiometer 9a is also supplied to the non-inverting input terminal of the comparator 9b. A signal S ₉ , ie an analog voltage representative of a particular reference steam load factor η, is provided.

Here, the specific measurement period set by timer 7a
Measuring the cumulative heating period ΣT ₁ during T ₃ corresponds to calculating the steam load factor of the boiler. Therefore, the above-mentioned reference steam load factor signal _S9 has its analog voltage set corresponding to a specific reference cumulative heating period of a specific measurement period.

Now, as shown in FIG. 4 Cm, if the cumulative heating period ΣT ₁ is smaller than the standard cumulative heating period _TR as the standard steam load factor signal S ₉ , then the comparator 9b of the steam load factor determination section 9 is , receives a smaller signal at its inverting input terminal than at its non-inverting input terminal, and outputs "1". At this time, the output signal of the comparator 9b and the sample hold signal from the monostable multivibrator 7b are input to the NAND gate 9c following the comparator 9b.
Since _S6 are both "1", the output signal of the NAND gate 9c, that is, the basic input command signal _S10 , is inverted from "1" to "0" as shown in FIG. 4Fn.

When the basic injection command signal ₉ is reversed from "1" to "0", the monostable multivibrator 10a of the can cleaner basic injection section 10 is triggered in response to the falling edge of the signal, as shown in FIG. 4G. Then, the positive phase output of the monostable multivibrator 10a becomes "1" during the quasi-stable period, and as a result, the relay 10c shifts to the excited state via the driver 10b, so the make contact _r10 closes and the motor 10d is driven,
Then, the basic amount of can cleaning agent is additionally added to the canned water by the pump 10e.

On the other hand, when the cumulative heating period ΣT ₁ ' measured by the steam load factor measuring section 8 is longer than the reference cumulative heating period T _R as shown by the broken line in FIG. Even if the heating device operating state signal S ₈ ′ sampled by the converter 8 d and converted into an analog signal is supplied to the inverting input terminal of the comparator 9 b, the reference steam signal S ₈ ′ is not supplied to the non-inverting input terminal. load factor signal
Since the output of the comparator _9b is not inverted and remains "0", the output of the NAND gate 9c becomes "1" as shown in FIG. 4 Fp.
maintain. As a result, the can cleaning agent basic injection part 10
The monostable multivibrator 10a is also not triggered, and its positive phase output is as shown in Fig. 4 Gq.
"0" is maintained, and therefore, the pump 10e is not driven and the can cleaning agent is not injected. In addition, counter 8
The contents of c are reset after the metastable time of the monostable multivibrator 7b has elapsed, as shown in FIG. 4Cr.

In this way, in this embodiment, the steam load rate of the boiler is measured based on the cumulative heating period of the heating device measured during a specific measurement period, and only when it is determined that the steam load rate is low, the boiler is cleaned by the basic input amount. Although the agent is put into canned water, the steam load rate of the boiler may be measured based on the cumulative heating stop period.

Next, with reference to Figure 5, regarding the change characteristics of the pH concentration of canned water in the boiler, we will explain how the steam load rate is 100%.
In the case of 20%, two examples are explained below.

Figure 5 is a graph showing time on the horizontal axis and the pH concentration of canned water on the vertical axis. Water with a constant amount of can cleaning agent added so that the pH is 7.0 is supplied to the water pipe. This is an example of operating the boiler after If the boiler is currently being operated with a steam load factor of 20% and the basic amount of can cleaning agent is not added, the pH concentration of the can water will gradually increase as shown by curve X. However, the pH concentration is suitable from the viewpoint of water pipe corrosion even after long-term operation.
It doesn't reach 11.0-11.8.

However, in a boiler equipped with the device of this invention, the steam load factor mentioned above is measured over a measurement period of about 2 hours after the boiler starts, and at the end of the measurement period, the steam load factor is low and the load factor does not reach the standard steam load factor. If it is determined that the pH level is the same, the basic amount of can cleaning agent will be injected at the end of the measurement period, and at that point, as shown by the broken line Y, the pH concentration of the can water will increase according to the basic amount. Although the pH gradually increases thereafter, it reaches a suitable pH concentration of 11.0 to 11.8 in a relatively short period of time.

On the other hand, when the boiler is operated at a steam load rate of 100%, no detergent is added at the end of the measurement period, but the pH concentration rises at a faster rate than when the steam load is 20%. Achieve a suitable pH concentration of 11.0 to 11.8 quickly.

As explained above, the present invention measures the steam load factor of the boiler during a specific measurement period after the boiler starts, and when it is determined that the steam load factor is lower than a preset reference load factor, Since the basic amount of can cleaning agent is automatically added to the water supply to which the same amount of can cleaning agent has been added, it is possible to accurately judge whether or not basic addition is necessary. , the basic injection is always carried out at the predetermined time, and the injection is not neglected.Therefore, there is an opportunity to operate the canned water at a suitable pH concentration of 11.0 to 11.8 for various steam loads, compared to the conventional method. This is much more than manual injection based on human judgment, and as a result, water pipes are less likely to corrode than in the past.

[Brief explanation of the drawing]

Figure 1A is a block diagram showing the configuration of a small boiler system to which the device of the present invention can be attached.
Figure B is a sectional view taken along the line AA of the boiler 1 in Figure 1A, Figure 2 is a block diagram showing the configuration of an embodiment of the present invention, and Figure 3 is a diagram showing the steam pressure detection section and heating control section of Figure 2. Waveform diagram showing the signals of each part, Figure 4 is the second
A waveform diagram showing the signals of each part of the heating control section, steam load rate measurement section, measurement period signal section, steam load rate determination section, and can cleaning agent basic injection section in the figure.
It is a graph showing the pH concentration of canned water on the vertical axis and the change in the pH concentration of canned water using the steam load rate as a parameter. 1... Boiler, 1f... Electric motor, 1g... Blower, 1j... Electrode rod, Ii... Fuel injection rod, 5...
Steam pressure detection unit, 6... Heating control unit, 6'... Fuel valve, 7... Measurement period signal unit, 8... Steam load rate measurement unit, 9... Steam load rate determination unit, 10... Clean can Drug basic injection department.

Claims (1)

[Claims] 1. In a boiler system having a heating device that heats canned water in a boiler water pipe, and a heating device control means that operates the heating device intermittently between the preset upper and lower limits of boiler steam pressure, Device 1
g, 1i, 1j for a predetermined measurement period via the heating control unit 6 to measure the steam load factor of the boiler; A steam load rate determination means 9 determines a low steam load rate based on the magnitude relationship, and when the steam load rate determination means 9 determines that the steam load rate is low, a basic amount of can cleaning agent is added to the water pipe. 1. A basic injection control device for can cleaning agent in a boiler system, characterized by comprising a basic injection means 10 for introducing can cleaning agent.