JPH0254897B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a diagnostic method and apparatus for a concentration detection device for canned water in a boiler. Generally, when a boiler system is operated for a long period of time, the canned water becomes concentrated, which increases the concentration of impurities such as calcium, magnesium, and silica contained in the canned water, which precipitates and adheres to the water pipes and grows into scale. It is. Since scale is a poor conductor of heat, the adhesion of scale not only reduces the efficiency of heat exchange in the boiler system, but also causes the water pipes to reach high temperatures.
It is known that this can eventually lead to burnout. Similarly, the concentration of impurities such as can cleaning agents increases, which induces a bubble layer in the can water, and the bubbles in the bubble layer turn into water and mix into the steam, causing carryover. It is also known that this can cause damage to related equipment such as valves connected to the boiler system. In order to prevent such scale growth and carry over, when the concentration of canned water has progressed to a certain extent, it is necessary to completely blow out the canned water (to completely drain the canned water) and replace it with fresh canned water. things are being done. Concentration detection devices using electrodes are in practical use, but the concentration is detected by the resistance value of the canned water between the electrode and the ground. However, deterioration of the insulation or disconnection between the electrodes or between the electrode and the ground could cause erroneous signals to be output. If insulation deterioration occurs between the electrodes or between the electrode and the ground, even if the canned water is completely drained and becomes fresh canned water, it may still be concentrated between the electrodes of the concentration detection device or between the electrode and the ground. When a current higher than the set current for detection flows, the concentration detection device sends a signal that the canned water is becoming concentrated, and if a complete blow is performed in response to this signal, it will be unnecessary unless some other preventive measure is taken. There is a risk of complete blowing. On the other hand, if there is a break in the circuit leading to the electrode or ground of the concentration detection device, even if the canned water is concentrated, the concentration of the canned water will be the same signal as fresh canned water, and the concentration detection device will detect a low concentration of canned water. No partial blows will be performed to let you know. An object of the present invention is to provide a diagnostic method and apparatus for determining whether a concentration detection device in a boiler equipped with a can water concentration detection device is operating correctly. The present invention provides a concentration detection device that includes a closed circuit in which a current increases in proportion to the conductivity of canned water according to the concentration of canned water, measures the current value, and outputs a concentration signal according to the current value. This is a method of guiding the concentration signal to at least two concentration signal level comparison means and determining whether the state of the concentration detection device is normal or abnormal based on the truth value of the output signal of the comparison means. Execute. In the present invention, a concentration detection electrode and a ground electrode are provided at intervals in a can body, and a current-voltage converter is provided in a closed circuit including a power supply that conducts electricity between the two electrodes, and converts a current value proportional to the concentration into a voltage value. The device is equipped with a can water concentration detection unit that converts the voltage to a set voltage using at least two comparators to make a determination, and is set to operate at a can water concentration that is approximately the same as the water supply after the boiler is fully blown. , a setting that does not operate at a canned water concentration similar to that of the boiler water supply after full blow-out, but operates at a predetermined concentration within the allowable concentration of canned water, and a setting that operates when the boiler canned water concentration exceeds a certain allowable value. It is equipped with a judgment circuit that diagnoses the concentration detection device by arranging comparators that operate at a set voltage value in parallel and judges the truth value of the output signal of each comparator. The apparatus is equipped with a means for detecting that the can water level after blowing has reached a certain level at which concentration detection should be performed, and the above-mentioned judgment circuit is operated by this detecting means. The means for detecting that the water level has reached a certain level at which this concentration detection should be performed is not particularly equipped, but as shown in the example, all blow detection devices are equipped with a measuring water level probe or the can water level is lower than the lower limit water level of the can water. It may also be a water level sensor for so-called interlock, which prevents the canned water from being heated when the temperature drops. Examples of the present invention will be described below. FIG. 1 is an explanatory diagram showing a method for detecting abnormality in the concentration detection section of boiler can water. It is assumed that the canned water inside the container 1x, which is in communication with the boiler can and into which the canned water is guided, exhibits the same behavior as the boiler can. The concentration detection electrode 7a is insulated from the container 1x and is fixed to the container 1x in contact with the can water, while the underwater electrode 2d is provided in the can water, and the concentration detection electrode 7a, the underwater electrode 2
An AC power source 2e and a current-voltage converter 7b for converting a flowing current value into a voltage value are arranged in series between d and serve as a concentration detection section whose output is the output voltage of the current-voltage converter 7b. On the other hand, a water level measuring electrode 7x is provided for detecting an abnormality in the concentration detecting section in order to operate the diagnosis of the concentration detecting device at a constant water level, and when the electrode 7x lands on water, it is electrically connected to the submerged electrode 2d through the canned water to form a closed circuit. A power source 2e and a current detector 2x are provided in the closed circuit. The output voltage of the current detector 2x is set to output a signal _S2 . The output terminal of the current voltage converter 7b is connected to the comparator 7.
Connect in parallel to the positive input terminals of A, 7B, and 7C. The operating voltage of the comparator 7A is determined by the current-voltage converter 7 depending on the conductivity of canned water, which is equivalent to the water supply to a boiler.
The comparator 7B is set to operate depending on the voltage outputted by Comparator 7B, and comparator 7B does not operate when the conductivity of canned water is comparable to that of boiler feed water, but when the concentration is below the allowable value where boiler canned water becomes concentrated and the concentration becomes large. The comparator 7C is set to operate when the concentration of boiler can water increases and exceeds a predetermined allowable value. When the can water is concentrated and the can water concentration increases, the conductivity of the can water decreases, so the resistance between the concentration detection electrode 7a and the underwater electrode 2d decreases, the current flowing through the current-voltage converter 7b increases, and its output voltage also increases. To increase. Furthermore, if the concentration detection section consisting of the concentration detection electrode 7a, the underwater electrode 2d, the power source 2e, and the current-voltage converter 7b is disconnected, no signal indicating that the can water is concentrated will be generated even if the concentration of the can water increases. Now, after all blowing has been performed, the can water level rises and when the concentration detecting section abnormality detection water level measuring electrode 7x lands on the water, the current detector 2x detects the current and outputs a signal _S2 . This signal can be known by, for example, a display. In this state, the current-voltage converter 7b is connected to the concentration detection electrode 7.
Since the resistance between a and the underwater electrode 2d is the largest, a low voltage is output to operate the comparator 7A, and the output is 1. The comparators 7B and 7C have an output of 0. However, when the insulation resistance of the concentration detection electrode 7a decreases due to dirt on the insulation part, a large current still flows through the concentration detection part even when water is supplied after full blowing, just as if the concentration of canned water had increased. Therefore, the current-voltage converter 7b outputs a large voltage. This voltage operates comparator 7B or comparators 7B and 7C. When the full blow is completed and the signal _S2 is input, the output of comparator 7A is 1, and the output of comparators 7B and 7C is 1.
The output of the comparator 7A should be 0, but if there is a disconnection in the concentration detection section, no current flows to the current-voltage converter 7b and the output voltage is 0, so the output of the comparator 7A is 0. In this way, it is possible to determine whether the concentration detection section is disconnected. To summarize the above operations,

[Table] Therefore, comparators 7A, 7B,
If the outputs of 7C are displayed respectively, it becomes clear that there is an abnormality in the concentration detection section. These judgments may be made by a logic circuit that outputs only the results. If the truth value is other than the above, comparators 7A and 7
It can be determined that the abnormality is B or 7C. Although three comparators were used in the above embodiment, a plurality of comparators may be used. In other words, the comparator 7A is always provided, but the minimum is the comparator 7B or 7.
Two pieces including C may also be used. Furthermore, in order to more precisely diagnose the degree of insulation failure in the concentration detection section by using three or more comparators, comparators 7A to 7 are used.
Comparators having different operating voltages may be sequentially arranged at operating voltages up to C. As described above, in a boiler equipped with a concentration detecting section, an abnormality in the concentration detecting section can be detected by comparing the output signal of the concentration detecting section with a comparator at the can water position at a constant water level after full blowing. Now, before explaining the subsequent embodiments of the apparatus 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. 2A is a block explanatory diagram showing the configuration of such a boiler system, and a cross section of the boiler 1 is shown. FIG. 2B is a sectional view taken along the line AA in FIG. 2A. 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, and an electric motor 1f is provided above the combustion chamber 1e.
An air passage 1h is provided which communicates with a blower 1g driven by a blower 1g, and a nozzle rod 1i and an electrode rod 1j are vertically provided within the air passage 1h. 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 its output terminal is connected to an electric motor 4a 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 portion thereof communicates with the lower header 1c. Further, a pressure detection section 5 is connected to the upper part of the communication pipe 1l, and its output terminal is connected to a combustion control section 6. From the combustion control unit 6, control signal lines 6a to 6
c extends and is connected to each of the electric motor 1f, electrode rod 1j, and fuel pump 6d. An inlet pipe of the fuel pump 6d communicates with a fuel tank (not shown), and a 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 blow 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 send air into the air passage 1h, and applies 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 this, 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 1d.
The steam is collected and stored at the steam pipe 1q and supplied to the steam load through the steam pipe 1q. Regarding combustion control, the upper header 1d
The steam pressure in the upper header 1d is extracted through the communication pipe 1l and supplied to the pressure detector 5.
When the combustion control section detects that the vapor pressure within the combustion chamber has reached a preset lower limit vapor pressure, the lower limit vapor pressure signal is sent to the combustion control section. Send to 6. When the combustion control unit 6 receives a lower limit steam pressure signal from the pressure detection unit 5 due to continued consumption of steam and the steam pressure in the upper header 1d falls, the combustion control unit 6 connects the control signal line 6 to the lower limit steam pressure signal from the pressure detection unit 5.
Start electric motor 1f through a, and blower 1g
After purging the air passage 1h with air, a high voltage is applied to the electrode rod 1j through the control signal line 6b, and at the same time, a high voltage is applied to the electrode rod 1j through the control signal line 6c.
starts, the fuel injected from the nozzle rod 1i is ignited to start combustion, and further, when steam generation continues and the steam pressure increases and an upper limit steam pressure signal is received from the pressure detection section 5, Combustion is stopped by stopping the fuel pump 6d and cutting off the fuel supply through the control signal line 6c, and after waiting for combustion gas to be discharged, the electric motor 1 is connected through the control signal line 6a.
Stop f and cut off the air from blower 1g. Thus, even with 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 canned 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 through the lower header 1c. 1
When the water supply to b is started, water supply continues, the can water level rises, 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. Thus, even with the 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. Also, regarding the blowing of canned water, blowing tips 1
By opening p, 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 configuration and operation of an embodiment of the present invention will be described below based on FIGS. 3 to 5. FIG. 3 is a block diagram showing the configuration of an embodiment of the present invention.
WL is expressed by replacing the water level in the communication pipe 1l with the canned water level in the corresponding water pipe, and for the sake of simplicity, a hypothetical water pipe 1b' with a simple shape is shown as the water pipe. ing. In addition, an expanded portion 1 formed at the bottom of the water pipe 1b'
c' is an equivalent representation of the lower header 1c in a hypothetical simple shape. The water level detection unit 2 includes a lower limit water level probe 2a disposed such that its tip is located at the lower limit setting position L of canned water in intermittent control of water supply, and a measurement unit for detecting full blow and concentration detection unit abnormality detection. A measurement water level probe 2b is disposed as an electrode so that its tip is located at the measurement setting position B below the lower limit setting position L, and an upper limit is arranged so that its tip is located at the upper limit position H of canned water. A water level probe 2c,
Underwater electrode 2d buried in can water and underwater electrode 2d
AC power supply 2e, one end of which is connected to AC power supply 2e, and current detectors 2f, 2g, inserted between the other end of AC power supply 2e and each of lower limit water level probe 2a, measurement water level probe 2b, and upper limit water level probe 2c. 2
It consists of h. The water supply control section 3 includes a flip-flop 3b, in which the output terminal of the current detector 2f is connected to its set terminal, and the output terminal of the current detector 2h is connected to its reset terminal through an inverter 3a, and a positive phase output of the flip-flop 3b. The terminal is driver 3c
and the other end is connected to the power supply 3.
d, and relay 3e connected to relay 3e.
The contact 3e' of e is the electric motor 4 that drives the water supply pump 4.
It is inserted into the power supply line 4b of a. The empty can state detection unit 8 includes a monostable multivibrator 8b whose input terminal is connected to the water supply command switch 8a, and a monostable multivibrator 8c whose input terminal is connected to the positive phase output terminal of the monostable multivibrator 8b. and a NAND gate 8d whose one input terminal is connected to the output terminal of the current detector 2g and the other input terminal is connected to the positive phase output terminal of the monostable multivibrator 8b, and whose input terminal is connected to the monostable multivibrator 8b. Monostable multivibrator 8 connected to the positive phase output terminal of 8c
e, a flip-flop 8f whose set terminal is connected to the output terminal of the NAND gate 8d, whose reset terminal is connected to the complementary output terminal of the monostable multivibrator 8e, and whose one input terminal is connected to the complementary output terminal of the flip-flop 8f. and the other input terminal is monostable multivibrator 8.
NAND gate 8g connected to the positive phase output terminal of c
A water supply command switch 8a' interlocked with the water supply command switch 8a is inserted into the power supply line 4b of the electric motor 4a for driving the water supply pump 4. The display unit 11 has an input terminal connected to the NAND gate 8.
a counter 11a connected to the output terminal of g, a driver 11b sequentially following the counter 11a,
It consists of a display tube 11c. A concentration detection electrode 7a is insulated and fixed to the lower header 1c' at a relatively lower part where it is not affected by a water level detection electrode such as a measuring water level probe 2b.
A closed circuit is made of the concentration detection electrode 7a, the current-voltage converter 7b that converts the current value into a voltage value, the AC power supply 2e, the underwater electrode 2d, and the canned water.The conductivity of the canned water makes this closed circuit. The flowing current is changed, and the current-voltage converter 7b constitutes a can water concentration detection section in which the current value is converted into a voltage value. The output terminal of the current-voltage converter 7b that outputs the voltage is coupled to the positive input terminals of the comparators 7A, 7B, and 7C, and the negative input terminals of the comparators 7A, 7B, and 7C are connected to a constant voltage via a variable resistor whose one end is grounded. has been added. Comparator 7A, 7
The output terminals of B and 7C are coupled to the input terminal of the judgment circuit 7d. The output terminal of the current detector 2g is connected in parallel to one input terminal of the NAND circuit 8d and to the input terminal of the judgment circuit 7d. The output terminal of the NAND circuit 8g is connected to the input terminal of the judgment circuit 7d in parallel with the input terminal of the counter 11a so as to obtain the output signal of the empty can state detection section 8. The judgment circuit 7d is the output signal from the NAND circuit 8g.
S ₅ followed by the signal from current detector 2g
When S ₂ is received, it operates and comparators 7A, 7B,
The truth value of the output signal of 7C is compared to determine whether the canned water concentration detection section is normal or not. If the canned water concentration detection section is normal, a signal corresponding to the concentration of canned water is output. The abnormal signal output terminal of the canned water concentration detection section of the judgment circuit _7d is connected to the concentration detection section abnormality alarm _7e . All blow signal output terminals of the judgment circuit 7d are connected to the driver 7g.
The output terminal of driver 7g is connected to relay RL2. Contact of relay RL2
RL2-1 is provided in the opening/closing circuit of the broker 1p. Further, the partial blow signal output terminal of the judgment circuit 7d is connected to the input terminal of the driver 7i, the output terminal of the driver 7i is wired to the timer relay T, and the contact T-1 of the timer relay T is connected to the opening/closing circuit of the blowing stock 1p through the contact RL2. -1 is arranged in parallel. Figure 4 shows change A in can water level and current detector 2.
h, 2f output signals B, C and flip-flop 3
FIG. 3 is a waveform diagram showing a comparison with a normal phase output signal D of FIG. First, the operation of water supply control with respect to the water level detection section 2 and water supply control section 3 in the above configuration will be explained as follows. Now, as shown in Fig. 4A, a, if the canned water level is higher than the lower limit setting position L,
The lower limit water level probe 2a is submerged in the can water, and conduction is established between it and the underwater electrode 2d through the can water,
Since a load circuit consisting of a current detector 2f, a lower limit water level probe 2a, and an underwater electrode 2d is formed for the AC power source 2e, a current flows through the current detector 2f,
Detecting this, the current detector 2f outputs "1" as shown in FIG. 4C and b. Then, when the can water level falls and reaches the lower limit setting position L as shown in FIG. Therefore, the current passing through the current detector 2f becomes zero, and upon detecting this, the current detector 2f outputs "0" as shown in FIG. 4C and d. In response to the inversion of the output signal of the current detector 2f from ``1'' to ``0'' at the set terminal, the flip-flop 3b is set to ``1'', and its positive phase output signal is shown in FIGS. 4D and 4E. As shown, it is inverted from "0" to "1". Upon receiving this signal, the driver 3c becomes conductive, the relay 3e is energized, the contact 3e' is closed, and power is supplied to the motor 4a through the water supply command switch 8a', which is closed at this point. Therefore, canned water is supplied to the water pipe 1b'. Thus, while the flip-flop 3b is at "1", water supply continues and the can water level continues to rise as shown in FIGS. 4A and 4F. Eventually, as shown in FIGS. 4A and 4G, when the can water level reaches the upper limit setting position H, the upper limit water level probe 2c is submerged, and since it has been far from the water surface, the water level in FIGS. “0” as shown in
The current detector 2h which had been outputting "1" now outputs "1" as shown in FIG. 4B, i. The inversion of the output signal of the current detector 2h from "0" to "1" is converted by the inverter 3a into an inversion from "1" to "0" and supplied to the reset terminal of the flip-flop 3b. "0"
Reset to . Then, as shown in FIG. 4D and j, the positive phase output signal of the flip-flop 3b becomes "0", so the relay 3e becomes de-energized, the contact 3e' opens, and the water supply stops. . In this way, the water supply period T ₁ from when the water supply pump starts until it stops is specified even during the period when the flip-flop 3b is set to "1", and furthermore, from when the water supply pump stops until it starts The water supply stop period T ₂ is the flip-flop 3b.
It is specified even during a period in which the value is "0". After the water supply is stopped, as shown in Figure 4 A and k, the can water level falls again at a rate of decline that corresponds to the amount of evaporation, and this reaches the lower limit as shown in Figure 4 A and l. The flip-flop 3b remains at "0" until it reaches the set position L, and then,
As shown in FIGS. 4D and 4m, it is reversed to "1" and a water supply stop period _T2 is formed. The same operation as above is repeated, and the can water level is maintained between the upper limit setting position H and the lower limit setting position L. Next, referring also to FIG. 5, the operation for detecting a complete blow during blowing work will be described as follows. Figure 5 shows change A in can water level and current detector 2.
The output signals of f and 2g, that is, the lower limit and measured water level signals B and C, the complementary output signal D of the flip-flop 8f, the positive phase output signal E of the monostable multivibrator 8b, and the output signal F of the NAND gate 8d.
FIG. 3 is a waveform chart showing a comparison between the output signal G of the NAND gate 8g and the positive phase output signal H of the monostable multivibrator 8c. When performing blowing work, the operator
p is opened and the water supply command switches 8a and 8a' are opened, and the relay contact 3 in the water supply control section 3 is opened.
Regardless of the intermittent operation of e', when the power supply to the electric motor 4a is cut off and the water supply pump 4 is stopped, the canned water in the water pipe 1b' is drained at a large flow rate through the drain pipe 1n. As shown in A, a, the can water level begins to fall rapidly. Then, as shown in FIGS. 5A and 5B, when the lower limit setting position L is reached, the lower limit water level probe 2a leaves the water surface, so that the output signal of the current detector 2f changes as shown in FIGS. 5B and C. It is inverted from "1" to "0" and the lower limit water level signal _S1 is output. During this time, the can water level continues to fall rapidly, as shown in Figures 5A and 5e, and when it reaches the measurement setting position B, as shown in Figures 5A and 5f, this time,
Since the measurement water level probe 2b leaves the water surface, the output signal of the current detector 2g is inverted from "1" to "0" as shown in Fig. 5C and g, and the measurement water level signal _S2 is output. . After performing complete blowing, the operator closes the blower stock 1p after performing inspection and maintenance inside the boiler as necessary, and then switches the water supply command switch 8a,
When a water supply command signal _S0 is given by closing 8a', the electric motor 4a for driving the water supply pump 4 is activated.
The power supply is now controlled by the opening and closing of the relay contact 3e', and the water supply intermittent control operation is started. At this point, regarding the intermittent control of the water supply, since the water level in the can is far below the lower limit setting position L, the intermittent control operation is performed, relay contact 3e' closes, and the water is supplied to the boiler. Canned water supply will begin. At the same time, the water supply command switch 8a is closed and the input terminal of the monostable multivibrator 8b is grounded, giving the water supply command signal _S0 . The multivibrator 8b is triggered and shifts to a metastable state. On the other hand, when water supply starts, the canned water level rises at a slow rate according to the water supply flow rate, as shown in Fig. 5A and k. Since the lower header 1c, which has a wide cross-sectional area equivalently expressed as part 1c', is filled with canned water, the rate of rise is extremely slow, and it takes a long time for the canned water level to rise. . After the lower pipe header 1c is filled with canned water, the water pipe 1b with a smaller cross-sectional area is filled, so the canned water level is as shown in Fig. 5A and l.
rises at a relatively fast rate. When the can water level reaches the measurement setting position B as shown in Fig. 5A, m, Fig. 5C, n
As shown in , the output signal of the current detector 2g is inverted from "0" to "1" and outputs the measured water level signal _S2 . However, in the case of water supply after complete blowing, it takes a long time to fill the lower header _1c . The monostable multivibrator 8b, which had transitioned to a stable state,
The stable state will be restored as shown in Figures E and P. Therefore, since "1" is not simultaneously supplied to the two input terminals of the NAND gate 8d, FIG.
As shown in , the gate 8d continuously outputs "1". Therefore, there is no change in the voltage at the set terminal of flip-flop 8f, and the positive phase output signal of flip-flop 8f remains at "0" as shown in FIG. 5D. Thus, the complementary output terminal of the flip-flop 8f continues to supply "1" as the empty can state detection signal _S4 to one input terminal of the NAND gate 8g. When the monostable multivibrator 8b returns to a stable state, the subsequent monostable multivibrator 8c is triggered and shifts to a quasi-stable state, and "1" is supplied to the other input terminal of the NAND gate 8g. . At this time, as mentioned above, if the empty can status is detected and the empty can status signal _S4 is intermittently output from the flip-flop 8f, "1" is supplied to both input terminals of the NAND gate 8g. Therefore, the output signal of NAND gate 8g is shown in Fig. 5 G, q.
As shown in FIG. 3, the complete blow detection signal _S5 is inverted from "1" to "0" and is output. Subsequently, when the monostable multivibrator 8c returns to a stable state as shown in FIG. 5H, z, the output signal of the NAND gate 8g changes from "0" to "1" as shown in FIG. 5G, r. At the same time, the monostable multivibrator 8e is triggered and shifts to a quasi-stable state, and upon receiving the inversion of the complementary output signal from "1" to "0" at the reset terminal, the flip-flop 8f changes to "0". ” is reset. Suppose now that for some reason, the water supply is not completely blown and the water level in the can is not zero, as shown in Figure 5A, i, and water supply is started from a state where canned water remains. , Figure 5A,
As shown in k', the can water level rises while missing some or all of the period required to fill the lower header 1c, so the time required to rise to the measurement setting position B is shortened. . Then, as shown in Fig. 5A, m', the can water level reaches the measurement setting position B, and as shown in Fig. 5C, n', the output signal of the current detector 2g becomes " 0”
At the time when the value is reversed from 1 to 1, the monostable multivibrator 8b is still in a quasi-stable state as shown in FIG. "1" from the monostable multivibrator 8b is supplied to the other input terminal, and as shown in FIG. 5F and v,
The output signal of the NAND gate 8d is from "1" to "0"
to be reversed. When this inverted signal is received at the set terminal, the flip-flop 8f is set to "1" as shown in Fig. 5D and w, its complementary output becomes "0", and the empty can state detection signal _S4 disappears. do. Therefore, in such a case, Fig. 5E,
Monostable multivibrator 8b as shown on p.
Even if the monostable multivibrator 8c eventually returns to a stable state and the subsequent monostable multivibrator 8c shifts to a metastable state,
Since the complementary output signal of the flip-flop 8f supplied to one input terminal of the NAND gate 8g is "0", the output signal of the NAND gate 8g becomes "1" as shown in FIG. 5G, x. The complete blow detection signal _S5 is not output. When the monostable multivibrator 8b returns to a stable state, as shown in FIG. 5F and y,
The output signal of the NAND gate 8d returns to "1" again. Next, the monostable multivibrator 8c is the fifth one.
As shown in Figures H and z, upon returning to a stable state,
As mentioned above, the monostable multivibrator 8e is triggered and shifts to the quasi-stable state, and upon receiving the inversion of its complementary output signal from "1" to "0" at the reset terminal, The flip-flop 8f is reset to "0" as shown in FIG. In this way, the empty can state detection unit 8 determines whether the can water level rises to the measurement setting position B within a specific period preset as the metastable time of the monostable multivibrator 8b. When performing water supply work after complete blowing, it is necessary to detect the elapse of the necessary water supply time for filling the lower header 1c with canned water and output a complete blow detection signal _S5 . When the complete blow detection signal _S5 is output, in response, the counter 11a counts the cumulative number of complete blows, and displays the display tube 11c through the driver 11b.
to visually display the cumulative number of complete blows. The total blow detection signal _S5 from the NAND circuit 8g is input to the input terminal of the judgment circuit 7d which is parallel to the input terminal of the counter 11a. At the same time, when the measurement water level probe 2b lands on the water, the output signal S ₂ =1 from the current detector 2g also enters the judgment circuit 7d, and in response, the output signal S ₆ , S ₇ , S ₈ from the comparators 7A, 7B, 7C. A comparison of truth values is performed. If the canned water concentration detection part is normal, the concentration detection electrode 7a
The resistance between the current and the underwater electrode 2d is the largest, and the current flowing to the current-voltage converter 7b is the smallest.
b operates only the comparator 7A and outputs S ₆ =1, and the output signals S ₇ and S ₈ of the comparators 7B and 7C
are respectively 0. However, the dirt from the boiler can water adheres to the insulating material of the concentration detection electrode 7a, and the resistance value between the electrode 7a and the lower header 1c' decreases, and the resistance between the concentration detection electrode 7a and the ground or the concentration detection electrode 7a decreases. Since the resistance value between the electrode 2d and the submerged electrode 2d decreases, a current flows through the current-voltage converter 7b just as when the canned water is concentrated, so the output voltage also exceeds a certain value within the permissible value for the concentration of canned water. When the comparator 7B is operated and the comparator 7A outputs an output signal S ₆ =1 and the comparator 7B outputs an output signal S ₇ =1, or the concentration of canned water exceeds the allowable value, the output voltage of the current-voltage converter 7b changes. becomes large and comparator 7B,
Operate both 7C and comparators 7A, 7B, 7
The output signals S ₆ , S ₇ , and S ₈ of C are all set to 1. Therefore, in a state where the water level probe 2b lands on the water after all of the canned water has been blown, only the output signal _S6 of the comparator 7A must be 1, so the judgment circuit 7d detects the concentration detection section abnormality signal. _S9 is output and displayed on the alarm 7e, and there is a decrease in resistance between the concentration detection electrode 7a and the underwater electrode 2d of the concentration detection circuit, or between the concentration detection electrode 7a and the ground.
Informs that insulation resistance has decreased. In addition, when the judgment circuit receives the total blow signal _S5 and the signal _S2 from the current detector 2g that monitors the water landing of the measurement water level probe 2b, if none of the comparators 7A, 7B, and 7C operate, the concentration detection Electrode 7a, canned water, underwater electrode 2d, AC power supply 2e, current-voltage converter 7b
The determination circuit 7d indicates whether there is a disconnection in the concentration detection section of the closed circuit connected in series, whether the AC power supply 2e is not energized, or whether the current-voltage converter 7b is malfunctioning and no output voltage is being output. In such a case, a concentration detection abnormality signal _S10 is generated to display the above-mentioned abnormality of the concentration detection device on the alarm 7f. Upon receiving the total blow signal _S5 and the landing signal _S2 of the measuring water level probe 2b, the judgment circuit 7d outputs the comparator 7.
If the output signal S ₆ of A is 1 and the output signals S ₇ and S ₈ of comparators 7B and 7C are both 0, it is normal, so after that, the concentration detection electrode 7a and the underwater electrode are When the resistance of the canned water between 2d and 2d decreases and the output voltage of the current-voltage converter 7b operates the comparator 7B, the judgment circuit 7d outputs a signal _S12 for performing a partial blow, and the driver 7
i, energizes the timer relay T, closes the contact T-1, and gradually opens the blowing stock 1p. As the canned water becomes more concentrated, the conductivity of the canned water between the concentration detection electrode 7a and the underwater electrode 2d decreases, so the current flowing through the current-voltage converter 7b increases and the output voltage exceeds the permissible value, causing the comparator 7A to , 7B, and 7C all operate, and the signals S ₆ , S ₇ , and S ₈ all enter the judgment circuit at 1, so the judgment circuit outputs a blow signal S ₁₁ .
It is amplified by the driver 7g, operates the relay RL2, closes the contact RL2-1, and opens the blowing stock 1p to perform full blowing. When the water level falls below the concentration detection electrode 7a or underwater electrode 2d, no current flows through the concentration detection circuit, so the current-voltage converter 7b does not output voltage, so the comparator 7
A, 7B, 7C are inactive, and signals S ₆ , S ₇ , S ₈
are all 0, so in response to this, the judgment circuit 7d
sets the signal _S11 to 0, deenergizes the relay RL2, and completes all blowing. Then, when water supply command switches 8a and 8a' are turned on, relay 3e is already energized and contact 3
Since e' is closed, the motor 4a is energized to operate the pump 4 and supply water to the boiler. When the can water level reaches the measurement water level probe 2b, the signal S ₂ of the current detector 2g is generated by the landing of the measurement water level probe 2b.
becomes 1, and as mentioned above, the output signal _S5 of the NAND circuit 8g of the empty can state detection section outputs 1, so the judgment circuit 7d detects the can between the concentration detection electrode 7a and the underwater electrode 2d. A current determined by the water concentration flows through the current-voltage converter 7b, and its output voltage is input to the comparators 7A, 7B, 7C, and the judgment circuit 7d judges the output signals S ₆ , S ₇ , S ₈ of the comparators 7A, 7B, 7C. to display the results. In this embodiment, an empty can state detection section 8 as shown in FIG. 3 is provided in order to obtain the total blow signal _S5 . However, in the present invention, it is only necessary to know that the full blow has been performed, and for this purpose, a low water level detection probe for confirming the full blow is provided in the can, which detects a low water level such that the water level of the can is completely blown. It may be provided internally, or it may be a visual water level gauge that can communicate with the canned water. A signal indicating that the water level of the can has been extremely reduced due to the full blowout may be manually or automatically input to the judgment circuit 7d. The display section 11 may have a structure in which the complete blow detection signal _S5 is displayed as it is by lighting as information indicating the execution of a complete blow, or an output signal processing device and a typewriter may be used instead of the display tube 11c etc. Each time a complete blow is performed with
A configuration may be adopted in which the date and time of execution is printed in a table along with the cumulative number of times. Furthermore, an arithmetic processing unit is attached to calculate the cumulative evaporation amount starting from the output point of the complete blow detection signal _S5 , and automatically control opening/closing of the blowing tank 1p, opening/closing of the water supply command switches 8a, 8a', etc. You can also use it as In the above embodiment, the surface of can water is detected using the lower limit and the conductivity between the measurement water level probes 2a, 2b and the underwater electrode 2d, but this is not limited to this. It is sufficient to detect the boundary surface of the lower limit, the measurement water level probe 2a, 2
In place of configurations such as b, an optical water level sensor consisting of a light emitting element and a light receiving element arranged opposite each other at the lower limit and the measurement setting position, and a magnetic sensor having a magnetic float placed at the lower limit and the measurement setting position may also be used. It is optional to employ lower limit, measuring water level sensors, including magnetic water level sensors and the like. Alternatively, a configuration may be adopted in which a water pressure signal proportional to the can water level is obtained from a single pressure sensor, and a comparator detects when this signal has reached the lower limit, a value corresponding to the measurement setting position. Furthermore, the measurement water level sensor is also commonly used as a water level sensor for so-called interlock, which prevents the canned water from being heated when the canned water level drops below the lower limit water level. It is also possible to have a configuration in which they are provided separately. As described above, the present invention includes a blowing stock that controls the blowing of canned water in a boiler, a water supply pump that supplies canned water to the boiler, and a control device that detects the canned water level and controls the operation of the water supply pump. Two electrodes are placed in the canned water and the electrodes are connected outside the boiler to form a closed circuit. During the closed circuit, a power supply is connected in series and the current flowing through the closed circuit is detected. The concentration of the canned water is determined by the output voltage. In a device equipped with a concentration detection unit that detects the amount of water and a means for detecting that the full blow has been performed, it is possible to detect that the canned water has reached a certain water level by the signal indicating that the full blow has been performed and the water supply after the full blow has been performed. A judgment circuit that diagnoses the concentration detection section by receiving the signal of the detection means and the output signals of a plurality of comparators that judge the output signal level of the concentration detection section, and when at least the concentration detection section is abnormal compared to the judgment circuit. Since the boiler is equipped with an abnormality detection device for the concentration detection section in a boiler that is equipped with an external display device that outputs a signal, it is possible to determine whether the concentration detection section of the canned water is abnormal or normal. Full blowing is performed even though the canned water is not concentrated, or conversely, scale is allowed to grow without fully blowing even though the canned water is concentrated, reducing the thermal efficiency of the boiler. Troubles that could damage related equipment can be avoided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the concentration detection method of the present invention, and FIG.
The following figures show an embodiment of the concentration detecting section abnormality detection device of the present invention.
FIG. 2B is a sectional view taken along the line A-A in FIG. 2A, FIG. 3 is a block diagram showing the configuration of an embodiment of the present invention, and FIG.
FIG. 5 is a waveform diagram of the main part. 1c'...lower can holder, 1p...brock stock,
1x...Container, 2b...Measuring water level probe, 2d
...Underwater electrode, 2e...AC power supply, 2g, 2x...
... Current detector, 3 ... Water supply control section, 4 ... Water supply pump, 7a ... Concentration detection electrode, 7b ... Current voltage converter, 7x ... Concentration detection section abnormality detection water level measurement electrode, 7d ... Judgment Circuit, 7A, 7B, 7C...
Comparator, 8... Empty can state detection section.

Claims (1)

[Scope of Claims] 1. A means is provided to detect a certain position where the water level of canned water rises when water is supplied after complete excretion in the boiler, and upon receiving the signal, changes in the conductivity of canned water provided in the boiler are provided. The signal level output by the concentration detection means that detects the water is detected using a comparator of the signal, and since the concentration indicated by the comparator is the concentration at the time of water supply, the concentration detection device is judged to be normal, and the comparator If the concentration shown is higher than the concentration at the time of water supply, it is determined that the insulation of the concentration detection electrode of the concentration detection means is poor, and if there is no output signal from the concentration detection means, it is determined that the concentration detection means is disconnected.Concentration in the boiler Detection unit abnormality detection method. 2. At least a block means for controlling the discharge of canned water in the boiler, a water supply means for supplying canned water to the boiler in response to the water supply command signal _S0 , and a detection device for generating a concentration signal according to the concentration of canned water. and a water level detection means for determining the concentration after the full blow, which issues a concentration judgment start signal for a water level below the detected water level of the lower water level detection means of the water supply control means, and a water level detection means for judging the concentration after the full blow has been performed. The empty can state detecting means receives the signal from the concentration detecting section and operates according to the signal from the concentration detecting section corresponding to the lowest concentration of canned water in the water supply state after full blowing based on the magnitude of the signal from the concentration detecting section. a plurality of comparators including a single comparator that operates based on a signal from the concentration detection unit at a concentration of canned water higher than the concentration in the water supply state after full blowing, or two or more comparators that operate based on concentration signals of different sizes; and a judgment circuit that operates in response to the signal of the water level detection means for determining the concentration after full blow and the full blow detection signal, compares and judges the output signals of a plurality of comparator groups, and outputs the result. Abnormality detection device for concentration detection section in boilers.