JPS6326281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a can water concentration measuring device for automatically measuring the increasing tendency of impurity concentration in can water due to the concentration of can water in a boiler system, and in particular, to The present invention relates to a can water concentration state monitoring device that detects the can water concentration state based on a significant decrease in the water supply cycle.

Generally, when a boiler system is operated for a long time, canned water becomes concentrated, and the concentration of impurities such as dissolved solids contained in the canned water increases, causing bubbles to form on the surface of the canned water. It is known that such bubbles leave the air-water interface and get mixed into the steam, causing carryover, which causes damage to related equipment such as valves connected to the boiler system.

In order to prevent carryover, the flow rate of water supply or steam can be measured with a flowmeter to estimate the concentration of canned water, and when this has increased to a certain extent, the canned water can be blown out (hereinafter referred to as blowout). ) and replacing the water with new canned water, however, it is generally difficult to install a flowmeter in small boiler systems because the economic burden of equipping it with a flowmeter is relatively large. Therefore, instead of measuring with a flowmeter, it is often possible to estimate the can water concentration by measuring the cumulative fuel consumption of the boiler system in units of storage vessels, typically drums. It is being done.

However, the measurement of cumulative fuel consumption using drums, etc., has not been carried out in the past because it involves the complicated work of counting and recording the number of drums, etc. in which consumed fuel was stored. It was often impossible to grasp the cumulative amount of evaporation and even the concentration of canned water.

Therefore, with such conventional boiler systems, it is not possible to accurately determine when to perform blowing.
This method has the disadvantage that it causes the canned water to become extremely concentrated, resulting in frequent carry-overs and an extremely high risk of damaging the load equipment.

The purpose of the present invention is to identify the water supply cycle based on the phenomenon that the water supply cycle in intermittent control of water supply decreases significantly under the concentrated state of canned water, in view of the problem of estimating the concentration of canned water based on the above-mentioned conventional technology. The present invention aims to provide an excellent can water concentration monitoring device in a boiler system that can eliminate the above-mentioned drawbacks and automatically monitor the concentration state of can water by determining when the water supply period has fallen below the reference water supply period. be.

The configuration of the present invention in accordance with the above object is that a lower limit water level sensor and an upper limit water level sensor are arranged to form a water level detection section, and canned water is supplied to the boiler in response to output signals from each of the upper and lower limit water level sensors. A water supply control unit is provided to start or stop the water supply pump, and when the canned water level drops as steam is consumed and reaches the lower limit water level, the lower limit water level sensor detects this and transmits the lower limit water level signal to the water supply control unit. When the canned water level rises and reaches the upper limit water level with the start of water supply, the upper limit water level sensor detects this and sends an upper limit water level signal to the water supply control unit to start the water supply pump. In a boiler system equipped with an intermittent control water supply control unit that stops the water supply, the water supply cycle measurement unit also measures the water supply period from when the water supply pump starts until it stops, and when the water supply pump starts after it stops. The water supply cycle consisting of the water supply stop period until When the period is below, the alarm display section displays an alarm indicating the state of concentration of canned water.

The structure and operation of the embodiment of the present invention will be described below based on FIGS. 1 to 4.

FIG. 1 is an explanatory block diagram showing a portion of a boiler system to which the configuration of the present invention is attached.
In the same figure, many of the water pipes 1 shown in the cross-sectional view are of the same shape, and are erected around the inner circumference of an annular can wall (not shown).
The upper parts of the water pipes 1 are connected to each other through an upper header 1a, and the lower parts thereof are connected to each other through a lower header 1b, surrounding the combustion chamber formed in the center of the can wall. It is arranged so that one side 1c serves as a heat receiving surface facing the combustion chamber.

A communication pipe 2 extends between the upper header 1a and the lower header 1b, and a water level gauge 3 and a water level detection section 20 are interposed in the communication pipe 2.

The steam separator 6 consists of a closed box with a separating plate 6a hanging from its top wall, and a steam pipe 5 extends from the top of the upper header 1a and is connected to the steam introduction hole 6b of the steam separator 6. A return pipe 7 extends from the return hole 6c of the separator 6 and is connected to the lower header 1b, and from the steam exhaust hole 6d of the separator 6,
Output tube 8 extends and is connected to a load device (not shown).

A water supply pipe 10 extending from a discharge port of a water supply pump 9 is connected to the lower header 1b, and a suction port of the pump 9 is connected to a water source (not shown).

11 is a blow tube.

The water sent through the water supply pipe 10 stays in the water pipe 1 as canned water W, and the water level is determined by the water level gauge 3 and the water level detector 20 through the communication pipe 2.
is transmitted to.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, in which the water level detection section 20 is connected to the communication pipe 2, and the water level detecting section 20 is connected to the communication pipe 2, and the water level detecting section 20 is connected to the communication pipe 2, and even if the water level is approximately equal to the water level of the can water in the water pipe 1. A filled detection tube 20a and a lower limit water level probe 2 disposed inside the detection tube 20a so that its tip is located at the lower limit water level L of canned water.
0b, an upper limit water level probe 20c disposed within the detection tube 20a so that its tip is located at the upper limit water level H of the canned water, and an underwater electrode 20d buried in the canned water within the detection tube 20a. An AC power source 20e whose one end is connected to the underwater electrode 20d, and an AC power source 20
A first current detector 20f inserted between the other end of e and the lower limit water level probe 20b, and an AC power supply 20
and a second current detector 20g inserted between the other end of e and the upper limit water level probe 20c.

The water supply control unit 21 includes a flip-flop 21b, in which the output terminal of the first current detector 20f is connected to its set terminal, and the output terminal of the second current detector 20g is connected to its reset terminal through an inverter 21a; The positive phase output terminal of 21b is connected to one end of the driver 21c, and the other end is connected to a power supply line 21d.The contact 21 of the relay 21e
e' is inserted into the power supply line 9b of the electric motor 9a that drives the water pump 9.

The water supply period measuring section 22 includes a clock pulse oscillator 22a and a first monostable multivibrator 22.
b and one input terminal is clock pulse oscillator 2.
2a, and the other input terminal is connected to the complementary output terminal of the first monostable multivibrator 22b; a counter 22d following the gate 22c; A second monostable multivibrator 22 follows the stable multivibrator 22b and has its complementary output terminal connected to the clear terminal of the counter 22d.
The input terminal of the first monostable multivibrator 22b is connected to the positive phase output terminal of the flip-flop 21b included in the water supply control section 21.

The canned water concentration state determination section 23 includes a digital-to-analog converter 23a which follows the counter 22d and whose load terminal is connected to the positive-phase output terminal of the first monostable multivibrator 22b, and whose inverting input terminal is connected to the digital-to-analog converter 23a. connected to the output terminal of the converter 23a,
Comparator 2 whose non-inverting input terminal is connected to power supply line 23c via potentiometer 23b
It consists of 3d. And the comparator 23d
An alarm display section 24 follows.

Figure 3 shows the can water level in water pipe 1, that is, the communication pipe 2.
Change A in the water level of canned water led into the detection tube 20a through the first and second current detectors 20f, 20
g output signals B and C and flip-flop 21b
positive phase output signal D, and positive phase output signal E of the first and second monostable multivibrators 22b, 22e,
FIG. 3 is a waveform chart showing a comparison between F and the content G of a counter 22d.

First, the operation of water supply control with respect to the water level detection section 20 and water supply control section 21 having the above-mentioned configuration will be explained as follows.

Now, as shown in Fig. 3Aa, when the can water level is between the upper and lower water limits H and L, the lower limit water level probe 20b is submerged in water, and conduction is established between the underwater electrode 20d and the AC power source. Since a load circuit consisting of a first current detector 20f, a lower limit water level probe 20b, and an underwater electrode 20d is formed for the current detector 20e, a current flows through the first current detector 20f, which is detected by the detector. 20f outputs "1" as shown in FIG. 3 Bb.

On the other hand, at this time, the upper limit water level probe 20c is not submerged in water, so no current flows through the second current detector 20g, and therefore it outputs "0" as shown in Figure 3 Cc. . Then, when the can water level rises and reaches the upper limit water level H as shown in FIG. 3 Ad, the upper limit water level probe 20c is submerged.
The second current detector 20g outputs "1" as shown in FIG. 3Ce. The inverted output signal as the upper limit water level signal _S2 outputted by the second current detector 20g is supplied to the reset terminal of the flip-flop 21b via the inverter 21a, and in response to this, the flip-flop 21b is reset.
The positive phase output signal is as shown in Figure 3 Df,
Invert from "1" to "0".

Then, the driver 21c becomes cut off, the relay 21e becomes de-energized, the contact 21e' opens, and the power supply to the motor 9a is cut off.
Water supply to water pipe 1 is stopped.

When the water supply is stopped, the canned water in the water pipe 1, which is heated by heat from a combustion chamber (not shown), evaporates into the upper header 1a as shown by the dotted line arrow in FIG. Since the can water is discharged from the output pipe 8 to the load equipment via the steam separator 6, the water level in the water pipe 1 gradually decreases as shown in Figure 3Ag, and eventually reaches the level shown in Figure 3Ah. As shown in , the lower limit water level L is reached.

At this time, the lower limit water level probe 20b, which had been submerged until now, leaves the can water surface, so the current passing through the first current detector 20f is cut off, and the detector 20f moves as shown in Figure 3 Bi. outputs "0".

The inverted signal as the lower limit water level signal _S1 outputted by the first current detector 20f is supplied to the set terminal of the flip-flop 21b, and upon receiving it,
The flip-flop 21b is set, and its positive phase output signal is inverted from "0" to "1" as shown in FIG. 3Dj.

Then, the driver 21c becomes conductive, the relay 21e becomes energized, the contact 21e' closes, and power supply to the motor 9a starts.
Water supply to the water pipe 1 is started.

When water supply starts, canned water is introduced into the water pipe 1 from the water supply pump 9 through the water supply pipe 10, as shown by the dashed-dotted line arrow in FIG. The water level rose at a relatively rapid rate, as shown in Figure 3 Ak, and eventually
As shown in Al, the upper limit water level H is reached.

At this time, the upper limit water level probe 20c, which had been far away from the can water surface, is submerged in water, so the second current detector 20g is set to "1" as shown in Figure 3 Cm.
In response to the inverted output signal as the upper limit water level signal _S2 , the flip-flop 21b is reset, and its positive phase output signal is again inverted to "0" as shown in FIG. Then, the water supply to the water pipe 1 is stopped.

In this way, there is a water supply stop period _T1 in which the flip-flop 21b is set to "0" and the supply of canned water to the water pipe 1 is stopped, and a period in which the flip-flop is set to "1" and the supply of canned water to the water pipe 1 is stopped. A water supply cycle T consisting of a water supply period _T2 is formed, and the water supply water level in the water pipe 1 reaches the upper and lower limit water levels H, It is maintained between L.

Next, the monitoring operation of the canned water concentration state with respect to the water supply period measurement section 22, the canned water concentration state determination section 23, and the alarm display section 24 will be explained as follows.

As shown in Figure 3 Ad and Figure 3 Df, when the can water level reaches the upper limit water level H and the flip-flop 21b is inverted to "0", it is triggered in response to this inverted output signal, and the first monostable multi-channel vibrator 2
2b is inverted to "1" during the metastable time, as shown in FIG. 3 Eo, so the multivibrator 2
2b is received at one input terminal, AND gate 22c is closed, and the supply of clock pulses from clock pulse oscillator 22a to counter 22d is cut off.

Then, the counting operation of the counter 22d stops,
As shown in FIG. 3 Gp, the contents of the counter 22d temporarily stop, and at this time, the load terminal receives the positive phase output signal "1" of the multivibrator 22b, and the digital-to-analog converter 23a
starts the processing operation.

When the quasi-stable time of the first monostable multivibrator 22b has elapsed, its positive phase output signal becomes "0".
, the subsequent second monostable multivibrator 22e is triggered, and as shown in FIG. is received at the clear terminal, the counter 22d is cleared, and its contents are held at zero as shown in FIG. 3 Gr.

When the quasi-stable time of the second monostable multivibrator 22e has elapsed, its complementary output signal becomes "1".
Therefore, the zero holding on the counter 22d is released.

At this time, the first monostable multivibrator 22b has already returned to "0" and the AND gate 22c is open, so the counter 22d starts counting clock pulses, and the contents are the third clock pulse.
As shown in Figure Gs, it increases over time.

Eventually, the water supply period T passes, and as shown in Figure 3 Al and Figure 3 Dn, the can water level returns to the upper limit water level H.
When the flip-flop 21b is reversed to "0", the first monostable multivibrator 22b transitions to a metastable state, and the and gate 22c closes, as shown in FIG. 3, Gt.
The contents of the counter 22d become static, but since the contents of the counter 22d at this time are the integrated value of the clock pulses during the water supply period T, the counter 22d generates a water supply period signal S representing the period T in a digital code. Outputs ₃ .

During the period when the contents of the counter 22d are stationary, the positive phase output of the first monostable multivibrator 22b is supplied to the load terminal of the digital-to-analog converter 23a, so that the converter 23a
Load the contents of the stationary counter 22d, that is, the water supply cycle signal _S3 , convert it into an analog voltage water supply cycle signal _S3 ', and load a new water supply cycle signal _S3 next time. The signal S ₃ ' is continuously outputted until.

The water supply cycle signal S ₃ ' is supplied to the inverting input terminal of the comparator 23d, and the reference water supply cycle signal set in advance by the potentiometer 23b is also supplied to the non-inverting input terminal of the comparator 23d. S ₄ , an analog voltage representing a particular reference watering period T ₀ is provided.

At this time, the water supply cycle T is the steady water supply cycle under the condition where there is no concentration of canned water, as shown in Figure 3A.
If T _s , the reference water supply period T _p is the steady water supply period
Since it is set below T _s , comparator 2
3d receives a larger signal at its inverting input terminal than that at its non-inverting input terminal, and becomes "0".
Output.

However, in general, regarding the water supply cycle of a boiler, once the concentration of canned water has progressed to a certain extent, apparent water supply cycles that are much shorter than the steady water supply cycle T _s will occur sporadically with a considerable probability. be.

The fourth waveform diagram exemplifies such short and short water supply cycles.
3A, and corresponds to FIG. 3A.

When the canned water in the water tube 1 reaches a certain level of concentration, a carryover occurs, and as shown by the solid arrow in Figure 1, the canned water in the water tube 1 flows into the space filled with steam above the surface of the canned water. , a two-phase flow of steam and water occurs within the space as a portion of the canned water is carried away.

Then, the can water level is as shown in Figure 4 a.
As part of the can water is carried away by the carry over, the can water rapidly falls and reaches the descending water level L. At this time, the carry over does not disappear immediately, so the can water The water level exceeds the lower limit water level L and further falls.

During this time, it is detected that the can water level is below the lower limit water level L, water supply is started, and the temperature of the can water decreases, so that the carry over temporarily disappears.

Then, the two-phase flow that was passing through the steam pipe 5 shown in FIG. The balance between the pressure loss ΔP that had been maintained and the head ΔH between the water surface in the steam-water separator 6 and the water level in the can is broken, and the pressure loss ΔP has become almost zero. , the head ΔH decreases,
Thus, the water separated and retained in the steam separator 6 is returned to the water pipe 1 through the return pipe 7.

As a result, as shown in FIG. 4c, the can water level rapidly rises beyond the upper limit water level H.

However, at this point, the temperature of the canned water has not decreased significantly, so when the canned water level exceeds the upper limit water level H and the water supply is stopped, carryover occurs again and grows further.

Then, the amount of canned water that exceeds the amount of water supplied in one intermittent control, that is, the amount of water held between the upper and lower limit water levels H and L in the water pipe 1, is carried away from the water pipe 1 at once, so the water level of the canned water is the fourth. As shown in Figure d, it exceeds the lower limit water level L and descends deeper.

Then, water supply is started again, the carry-over is temporarily eliminated, and a large amount of water is returned from the steam-water separator 6 in the same manner as above, so that the canned water level becomes as shown in Fig. 4e. , the water level rises rapidly once again exceeding the upper limit water level H, but at this point, the temperature of the canned water has dropped considerably due to the two water supplies in a short period of time, so the canned water level exceeds the upper limit water level H. Carry over does not occur again even if the water supply is stopped.

Thus, the can water level falls at a relatively slow rate depending on the amount of evaporation, as shown in FIG. 4f.

The apparent water supply period T′ caused by this vibration phenomenon is unique to each boiler system,
And the steady water supply period T _s in a normal boiler system
It is a much shorter period.

Returning to FIG. 2, when the above vibration phenomenon occurs as the canned water becomes concentrated, the comparator 23d
Water supply periodic signal supplied to the inverting input terminal of
Since S ₃ ' is smaller than the reference water supply period signal S ₄ supplied to the non-inverting input terminal, the output signal of the comparator 23d is inverted to "1", and this inverted signal is the canned water concentration state signal. Alarm display section 2 as S ₅
4.

When the alarm display unit 24 receives the canned water concentration state signal _S5 , it temporarily stores it and continuously displays that the canned water has reached the concentrated state until it is manually reset.

At this time, a counter is attached to the alarm display section 24 to count the number of supplied canned water concentration status signals _S5 , detect that a specific number has been reached, and display an alarm. It is optional to adopt a configuration that more reliably determines the concentration state of canned water.

Next, the configuration of the second invention that is related to this invention is that, apart from the upper and lower limit water level sensors for water supply control, there is a canned water level at a measured water level arbitrarily determined between the upper limit water level and the lower limit water level. detect that
A measurement water level sensor that outputs a measurement water level signal is attached, and the time interval of the measurement water level signal is typically determined between the first time when the rising canned water level reaches the measurement water level and the time after the rising can water level reaches the upper limit water level. The water supply cycle is measured based on the time difference between the can water level falling to the lower limit water level and rising again and the second time point when the can water level reaches the measured water level again, and the can water concentration state determination unit also performs the following steps:
A specific reference water supply cycle set in advance is compared with the above water supply cycle in magnitude, and if the water supply cycle is less than or equal to the reference water supply cycle, an alarm is displayed on the alarm display section to indicate the canned water concentration state. It is characterized by the following.

The configuration and operation of the second invention related to the present invention will be explained as follows based on FIGS. 5 and 6.

FIG. 5 is a block diagram showing the configuration of the second invention, in which the water level detecting section 20' has the upper and lower water limits H, L.
A measurement water level probe 20'h is disposed within the detection tube 20a so that its tip is located at a measurement water level M arbitrarily determined between the two, and the other end of the AC power supply 20e and the measurement water level probe 20'h A third current detector 20'i inserted between It is connected to the water supply cycle measuring section 22.

The other components are the same as those indicated by the same reference numerals in FIG.

Figure 6 shows the change A in the can water level in the detection tube 20a.
and the output signal H of the third current detector 20'i,
3 is a waveform diagram showing a complementary output signal I of the Schmitt circuit 25 in comparison. FIG.

In the above configuration, as shown in FIG. 6Aa, when the can water level is below the measurement water level M, the measurement water level probe 20'h is not submerged in water, so the third current detector 20'i is As shown in Figure 6 Hb,
"0" is output, and eventually the can water level rises,
As shown in FIG. 6 Ac, when the measurement water level M is reached, the measurement water level probe 20'h is submerged in water, so the third current detector 20'i is 0” to “1”.

This inverted signal is supplied to the Schmitt circuit 25 as the measured water level signal _S6 , and the Schmitt circuit 2
In response to this, 5 reversed from "0" to "1",
The complementary output signal is, as shown in FIG. 6Ie,
Invert from "1" to "0".

When the canned water level further rises and reaches the upper limit water level H as shown in FIG. 6 Af, the water supply control unit 21
operates as described above, the water supply is stopped, and the
As shown in Ag, the can water level drops. When the falling can water level reaches the measurement water level M as shown in Fig. 6Ah, the measurement water level probe 20'h moves away from the can water surface again, and as shown in Fig. 6Hi,
Since the output signal of the third current detector 20'i is inverted to "0" and becomes the measured water level signal _S6 , the complementary output signal of the Schmitt circuit 25 becomes "1" again, as shown in FIG. to be reversed.

When the canned water level further falls and reaches the lower limit water level L as shown in FIG. 6 Ak, the water supply control unit 21
However, the system operates again as described above, water supply starts, and the water level in the can rises as shown in Al in the same figure.
As shown in Figure 6 Am, the rising can water level
When the measurement water level M is reached, the measurement water level probe 2
0'h is submerged in water again, and as shown in Hn in the same figure, the output signal of the third current detector 20'i is inverted to "1" and becomes the measured water level signal _S6 , so the signal is changed to Io in the same figure. As shown, the complementary output signal of the Schmitt circuit 25 is again inverted to "0".

One period of the complementary output signal of the Schmidt circuit 25 in such an operation, that is, the first time point when the rising can water level reaches the measured water level M as shown in FIG. The time difference between the second point in time when the canned water level rises to the upper limit water level H, then falls to the lower limit water level L, and then rises again reaches the measured water level M, is the water supply cycle T in Fig. 3A.
Therefore, the complementary output signal of the Schmitt circuit 25 should be supplied to the subsequent water supply cycle measuring section 22 instead of the positive phase output signal of the flip-flop 21b in the configuration of the present invention explained based on FIG. For example, the subsequent configuration operates in exactly the same manner as the configuration of the present invention described above, and is capable of determining the concentration state of canned water and displaying an alarm.

As described above, this invention and the second invention linked to this invention both focus on the phenomenon that short water supply cycles due to carry over appear sporadically as canned water concentration progresses. , is configured to measure the water supply cycle in intermittent water supply control, and determine that this is less than a preset specific reference water supply cycle to detect the canned water concentration state and display an alarm. Therefore, an alarm is automatically displayed when canned water concentration has progressed to a certain extent, and there are no accidents caused by negligence in recording work, etc., unlike in the case of counting the quantity of drum cans, etc. in the past. It is possible to reliably know that the canned water has reached a state of concentration that requires blowing work.

Therefore, according to this invention and the second invention linked thereto, both have the excellent effect of avoiding the continuous occurrence of carry-over and preventing damage to the load equipment.

In particular, the water level detection section and water supply control section in the configuration of this invention are essential components for intermittent control of water supply, and they can be used as they are,
Since it is sufficient to add a configuration for processing the start/stop signal of the water supply pump obtained from the water supply control unit, there is an advantage that the configuration is simple, there is no waste, and it can be realized at low cost. Compared to the configuration of the invention, the measuring water level probe 20'
The same effect as the configuration of the second invention can be obtained without adding h and the third current detector 20'i.

[Brief explanation of drawings]

Fig. 1 is a block explanatory diagram showing a part of the boiler system to which the configuration of the present invention is attached, and Figs.
FIG. 4 relates to an embodiment of this invention,
FIG. 2 is a block diagram showing its configuration, FIG. 3 is a waveform diagram of its essential parts, and FIG. 4 is a graph illustrating short-period canned water level fluctuations due to carry over. 5 and 6 relate to an embodiment of the second invention linked to the present invention, FIG. 5 is a block diagram showing its configuration, and FIG. 6 is a waveform diagram of the main part thereof. 1...Water pipe, 2...Communication pipe, 5...Steam pipe, 6
... Steam separator, 7 ... Return pipe, 8 ... Output pipe,
9... Water supply pump, 10... Water supply pipe, 20,2
0'...Water level detection section, 20a...Detection tube, 20b
...Lower limit water level probe, 20c...Upper limit water level probe, 20d...Underwater electrode, 20f, 20g, 2
0'i...Current detector, 20'h...Measurement water level probe, 21...Water supply control section, 22...Water supply cycle measurement section, 23...Canned water concentration state determination section, 24...Alarm display section.

Claims (1)

[Claims] 1. A lower limit water level sensor 20b that detects that the can water level is at the lower limit water level and outputs a lower limit water level signal _S1 ;
20f, and an upper limit water level sensor 2 that detects that the canned water level is at the upper limit water level and outputs an upper limit water level signal _S2 .
0c, 20g, and the water supply pump 9 that supplies canned water to the water pipes in response to the lower limit water level signal _S1 is started, and the water supply pump 9 is stopped in response to the upper limit water level signal _S2 . In a boiler system equipped with an intermittent control water supply control means 21, the water supply period T ₂ from when the water supply pump 9 starts to when it stops.
and the water supply period _T1 from when the water supply pump 9 stops to when it starts, is measured,
The water supply cycle measurement means 22 outputs the measurement result as a water supply cycle signal _S3 , and the water supply cycle is determined to be longer than the steady water supply cycle _Ts based on the water supply cycle signal _S3 and a preset reference water supply cycle signal _S4 . Canned water concentration state determination means 2 that determines that it is less than or equal to a small specific reference water supply period T _p and outputs a canned water concentration state signal S ₅
3, and alarm display means 24 for displaying an alarm in response to the can water concentration state signal _S5 . 2. A lower limit water level sensor 20b that detects that the can water level is at the lower limit water level and outputs a lower limit water level signal _S1 ;
20f, and an upper limit water level sensor 2 that detects that the canned water level is at the upper limit water level and outputs an upper limit water level signal _S2 .
0c, 20g, and the water supply pump 9 that supplies canned water to the water pipes in response to the lower limit water level signal _S1 is started, and the water supply pump 9 is stopped in response to the upper limit water level signal _S2 . In a boiler system equipped with an intermittent control water supply control means 21, a measurement method for detecting that the can water level is a measured water level arbitrarily determined between an upper limit water level and a lower limit water level and outputting a measured water level signal _S6 The water level sensors 20'h, 20'i, the water supply cycle measuring means 22 which measures the water supply cycle T based on the time interval of the measured water level signal _S6 , and outputs the measurement result as the water supply cycle signal _S3 ; Periodic signal S ₃
and a preset reference water supply cycle signal _S4 , determine that the water supply cycle is less than or equal to a specific reference water supply cycle _Tp that is smaller than the steady water supply cycle _Ts ,
Canned water in a boiler system comprising a canned water concentration state determination means 23 that outputs a canned water concentration state signal _S5 , and an alarm display means 24 that displays an alarm in response to the canned water concentration state signal _S5 . Concentration status monitoring device.