JPH0210326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an evaporation amount measuring device for automatically measuring the steam load of a boiler system, that is, the amount of evaporation, and particularly relates to a heating control device for heating canned water in a boiler system. The present invention relates to an evaporation amount measuring device that measures evaporation amount based on both a heating period and a heating stop period in intermittent system control.

In general, in boiler systems, it is known that during long-term operation, factors that inhibit operation increase in accordance with the cumulative amount of evaporation, such as carry over and scale growth due to concentration of canned water.

Furthermore, since there are control targets in the boiler system, such as water supply volume, which are controlled to appropriate amounts according to the amount of evaporation, it is necessary to judge whether these controls are being performed appropriately based on the amount of evaporation. However, backup measures are taken in case of unsuitability, and it is also known that the amount of evaporation is important basic data for the operational management of boiler systems.

Therefore, in order to understand the amount of evaporation as basic data for operation management, the flow rate of the evaporation load is often measured using a flowmeter, but in small boiler systems, the flow rate is Since the economic burden of equipping a vehicle with a meter is relatively large, it has generally been difficult to adopt it.

Therefore, with conventional small boiler systems, it was not possible to accurately determine the amount of evaporation, so not only was it not possible to provide sufficient backup protection for water supply control systems, etc. The drawback was that there was an extremely high risk of water pipe burnout due to breakage and scale growth.

The purpose of the present invention is to measure the heating period and heating stop period in intermittent control of the heating control system without using a flow meter, and to measure both the heating period and the heating stop period in the intermittent control of the heating control system, in view of the problems in measuring the amount of evaporation in a boiler system based on the above-mentioned conventional technology. By calculating the amount of evaporation based on the measurement results of
It is an object of the present invention to provide an excellent evaporation amount measuring device for a boiler system that can eliminate the above-mentioned drawbacks and automatically measure evaporation amount.

The configuration of the present invention in accordance with the above object includes a pressure sensor that outputs a steam pressure signal corresponding to the steam pressure in the water pipe, and a pressure sensor that detects that the steam pressure signal has reached an upper and lower limit set value corresponding to the upper and lower limit steam pressure. a first and second comparator to form a vapor pressure detection section;
A heating device, typically a heating control, for starting or stopping a burner is provided for heating the water tube in response to an output signal from each of the first and second comparators, so that the water tube is heated as steam is consumed. When the steam pressure of When the vapor pressure increases and reaches the upper limit vapor pressure, the second comparator detects this and sends an upper limit vapor pressure signal to the heating control section to stop the heating device.Intermittent control heating control In the boiler system equipped with the system, a heating period measuring section and a heating stop period measuring section are attached to measure the heating period from when the heating device starts until it stops,
Measures both the heating stop period from when the heating device stops until it starts, and furthermore, an evaporation amount calculation unit is attached to calculate the evaporation amount based on both the heating period and the heating stop period. It is characterized by the following.

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 the line AA in FIG. 1A.

In the figure, inside a boiler 1, a large number of water pipes 1b are installed along the inner circumferential surface of a wall 1a, and the water pipes 1b are made of a hollow cylindrical body, and the lower end thereof is an annular lower header 1c (water chamber). The upper end portions thereof communicate with an annular upper header 1d (steam chamber), and canned water is stored in the lower portions of the lower header 1c and the 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 an electric motor 4a that drives a water supply pump 4 is connected to an output terminal thereof. 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.

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 section 6, control signal lines 6'a~
6'c extends and is connected to each of the electric motor 1f, electrode rod 1j, and fuel pump 6'd. An inlet pipe of the fuel pump 6'd communicates with a fuel tank (not shown),
Its discharge pipe communicates with the nozzle rod 1i. and,
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 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 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 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 pressure detector 5, the combustion control section 6 starts the electric motor 1f via the control signal line 6'a. Then, the air passage 1h is purged with air using the blower 1g, and then a high voltage is applied to the electrode rod 1j through the control signal line 6'b, and at the same time, the fuel pump 6'd is started through the control signal line 6'c. , the fuel injected from the nozzle rod 1i is ignited to start combustion, and further, steam generation continues and the steam pressure increases, and the pressure detection unit 5
When the upper limit vapor pressure signal is received from the control signal line 6'c, the fuel pump 6'd is stopped,
Combustion is stopped by cutting off the fuel supply, and after waiting for combustion gas to be discharged, the control signal line 6'
Through a, the electric motor 1f is stopped and air from the blower 1g is cut off.

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 6'd, and the application of high voltage to the electrode rod 1g 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.

Furthermore, 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 configuration and operation of an embodiment of the present invention will be described below based on FIGS. 2 to 9.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, and in the figure, components denoted by the same reference numerals as those in FIG. 1 correspond to those in FIG. 1, respectively.

The pressure detection unit 5 includes a pressure sensor 5a to which the steam pressure in the upper header 1d is guided through the communication pipe 1l;
First and second comparators 5 whose respective first input terminals are connected to the output terminal of the pressure sensor 5a.
b, 5c, and first and second comparators 5b, 5
and reference voltage sources 5d and 5e, respectively connected to the second input terminal of c.

The heating control section 6 includes a flip-flop 6b, in which the output terminal of the first comparator 5b is connected to its set terminal, and the output terminal of the second comparator 5c is connected to its reset terminal through an inverter 6a, and a positive-phase flip-flop 6b. It consists of a relay 6e whose output terminal is connected to one end through a driver 6c and the other end connected to a power source 6d, and the contacts 6'e, 6''e, 6e of the relay 6e are connected to the electric motor 1f, the electrode rod 1j, and the combustion pump. It is inserted between each of control signal lines 6'a, 6'b, and 6'c for controlling 6'd and the power supply.

The heating period measuring section 7 includes a clock pulse oscillator 7.
a and one input terminal is the clock pulse oscillator 7.
an AND gate 7b, which is connected to the output terminal of the flip-flop 6b, and whose other input terminal is connected to the positive phase output terminal of the flip-flop 6b; and a counter 7c, whose input terminal is connected to the output terminal of the AND gate 7b.
, its input terminal is connected to the positive phase output terminal of flip-flop 6b, and its output terminal is connected to counter 7
It consists of a monostable multivibrator 7d connected to the clear terminal of c.

The heating stop period measuring section 8 consists of an AND gate 8b, a counter 8c, and a monostable multivibrator 8d connected in exactly the same way as the heating period measuring section 7, and one input terminal of the AND gate 8b is connected to the output of the clock pulse oscillator 7a. terminal and one other input terminal are respectively connected to the complementary output terminal of flip-flop 6b.

The evaporation amount calculation unit 9 includes a microprocessor 9d, a memory 9e, and a memory 9e, which are interconnected by a data bus 9a, an address bus 9b, and a control bus 9c.
First, second, and third input ports 9f, 9g, and 9h, output port 9i, and first, second, and third interrupt control lines 9
j, 9k, 9m, the second and third interrupt control line 9
It consists of monostable multivibrators 9n and 9p whose complementary output terminals are connected to terminals k and 9m, and the input terminals of second and third input ports 9g and 9h are connected to the output terminals of counters 7c and 8c, respectively. A data line extending from the constant setting unit 10 including the keyboard 10a is connected to the input terminal of the first input port 9f, and the input terminals of the monostable multivibrators 9n and 9p are connected to the positive phase output of the flip-flop 6b. terminal and complementary output terminal, respectively.

Note that 11 is a display section connected to the output port 9i.

Figures 3 and 5 show the change A in the steam pressure in the upper header 1d extracted to the communication pipe 1l, and the upper and lower limit steam pressure signals B and C output by the first and second comparators 5b and 5c. , is a waveform diagram showing a comparison of the positive phase output signals D and E of the flip-flop 6b.

In the above configuration, first, the operations of the pressure detection section 5 and the heating control section 6 will be explained as follows.

The pressure sensor 5a responds to the steam pressure in the upper header 1d guided through the communication pipe 1l and outputs a corresponding steam pressure signal _S1 , as shown in FIG. 3Aa. When the vapor pressure is higher than the lower limit vapor pressure L, the vapor pressure signal corresponding to the lower limit vapor pressure L is supplied from the reference voltage source 5d.
Since the vapor pressure signal S ₁ is larger than the reference voltage V _L which is equal to the lower limit set value of S ₁ , the first comparator 5b detects this and outputs "1" as shown in FIG. 3 Cb. do.

Then, as the steam is consumed or the temperature decreases, the steam pressure decreases, as shown in Figure 3 Ac.
When the lower limit vapor pressure L is reached, the vapor pressure signal S ₁ becomes smaller than the reference voltage V _L , so detecting this, the first comparator 5b outputs "0" as shown in FIG. 3 Cd.

Upon receiving the inversion of the output signal of the first comparator 5b from "1" to "0" at the set terminal, the flip-flop 6b is set to "1", and its positive phase output signal is as shown in FIG. 3 De. ``0''
to "1". Upon receiving this signal, the driver 6c becomes conductive, the relay 6e is excited, the contacts 6'e, 6''e, and 6e are closed, and power is supplied to the motor 1f, electrode rod 1j, and combustion pump 6'd. Therefore, the canned water is heated.

Thus, while the flip-flop 6b is at "1", heating continues and the vapor pressure continues to rise as shown in FIG. 3Af.

Eventually, as shown in FIG. 3Ag, when the vapor pressure reaches the upper limit vapor pressure H, the vapor pressure signal S ₁
is smaller than the reference voltage _VH , which is equal to the upper limit set value of the vapor pressure signal _S1 corresponding to the upper limit vapor pressure supplied from the reference power source 5e, so it is set to "0" as shown in FIG. 3Bh. The second comparator 5c which had been outputting now outputs "1" as shown in FIG. 3 Bi.

The inversion of the output signal of the second comparator 5c from "0" to "1" is converted by the inverter 6a into an inversion from "1" to "0" and supplied to the reset terminal of the flip-flop 6b.
Reset this to "0".

Therefore, as shown in FIG. 3Dj, the positive phase output signal of the flip-flop 6b becomes "0", so
Relay 6e becomes de-energized, contacts 6'e,
6″e and 6e are opened, and heating of the canned water is stopped.

In this way, the period from when the heating device starts until it stops (hereinafter referred to as the heating period) can be specified even during the period when the flip-flop 6b is set to "1", and furthermore, the period from when the heating device stops until it stops is specified. The period until this happens (hereinafter referred to as the heating stop period) is as follows:
This is specified even during the period when the flip-flop 6b is at "0".

After stopping heating, as shown in Figure 3 Ak,
The flip-flop 6b remains at "0" until the steam pressure decreases again as the steam is consumed or the temperature decreases and reaches the lower limit steam pressure L, forming a heating stop period _T2 , and then, Similar operations are repeated to maintain the vapor pressure between the upper limit vapor pressure H and the lower limit vapor pressure L.

For example, if the amount of evaporation (steam load) increases during the process of increasing steam pressure, heating of canned water,
The amount of heat flowing into the boiler system due to the supply of canned water,
Where the amount of heat flowing out of the boiler system due to heat radiation is approximately constant during the heating period during steady operation,
The amount of heat flowing out of the boiler system due to evaporation of can water increases in proportion to the amount of evaporation, so more heat is taken away from the boiler system, and as shown in Figure 3 Af', the steam pressure increases. The slope becomes slower.

Therefore, hypothetically, at the point shown in Figure 3 Ac,
At the same time, as shown in FIG. 3Ee', assuming that the flip-flop 6b is inverted to "1" and the heating period begins, if the amount of evaporation increases, the third
At the time shown in Figure Ag', the flip-flop 6b is inverted to "0" as shown in Figure 3 Ej', so the heating period is longer than the heating period _T1 before the amount of evaporation increases. T′ ₁ is formed.

The heating period T ₁ varies depending on the amount of evaporation
FIG. 4 is a graph illustrating the general tendency of change.

As is clear from the figure, in the region where the heating period T ₁ is small, in other words, in the region where the amount of evaporation is small,
The increase or decrease in the amount of evaporation corresponding to the increase or decrease in the unit amount during the heating period _T1 becomes extremely large, and the slope of the curve tends to become steeper.

Next, for example, if the amount of evaporation (steam load) increases during the step of lowering the steam pressure, there is no amount of heat flowing into the boiler system due to the heating of the canned water, and furthermore, the amount of heat flowing into the boiler system is increased by the supply of canned water. Where the amount of heat flowing into the system and the amount of heat flowing out from the boiler system due to heat radiation are approximately constant during the heating stop period during steady operation,
The amount of heat flowing out of the boiler system due to evaporation of canned water increases in proportion to the amount of evaporation, so as in the process of increasing steam pressure, more heat is taken away from the boiler system, as shown in Figure 3. Figure 5 corresponds to
As shown by Ak′, the downward gradient of vapor pressure becomes steeper.

Therefore, hypothetically, at the point shown in Figure 5Ag,
At the same time, as shown in FIG. 5 Ej', assuming that the flip-flop 6b is reversed to "0" and the heating stop period has started, if the amount of evaporation increases, then
At the time shown in Fig. 5 Al', the flip-flop 6b is inverted to "1" as shown in Fig. 5 Em', so that the heating stop period _T2 before the evaporation amount increases is shorter A heating stop period _T'2 is formed.

The heating stop period varies depending on the amount of evaporation.
FIG. 6 is a graph illustrating the general change trend of T ₂ .

As is clear from the figure, in the region where the heating stop period T ₂ is small, in other words, in the region where the evaporation amount is large, the increase or decrease in the evaporation amount corresponding to the increase or decrease in the unit amount of the heating stop period T ₂ becomes extremely large. The slope of the curve tends to become steeper.

This tendency is in contrast to the tendency of the curve in FIG. 4, which becomes steeper in the region of small evaporation.

The following is a quantitative consideration of the interrelationship between the amount of evaporation, the heating period, and the heating stop period, which have been qualitatively explained above.

Generally, the change dU in the internal thermal energy possessed by a boiler system is expressed as dU = ηB・H _U・dt+G _W・I _W・dt −G _S・I _S・dt−Q _R・dt (1).

However, η... Boiler efficiency (excluding heat radiation loss) B... Calorific value of fuel H _U ... Fuel consumption (flow rate) G _W ... Water supply amount to the boiler (flow rate) I _W ... Enthalpy of water supply G _S : Amount of evaporation (flow rate) I _S : Enthalpy of steam Q _R : Amount of heat radiation from the boiler (heat flow rate).

Regarding the right side of equation (1), the first term is the amount of heat flowing into the boiler system due to heating of can water, the second term is the amount of heat flowing into the boiler system due to supply of can water, and the third term is the amount of heat flowing into the boiler system due to the supply of can water.
The term represents the amount of heat flowing out of the boiler system due to evaporation of canned water, and FIG. 4 represents the amount of heat flowing out from the boiler system due to heat radiation.

By the way, in general, in a boiler system, the amount of fluctuating canned water that is replenished by intermittent control of the water supply system is negligibly small compared to the amount of canned water held during operation. The minimum amount of water that can be stored is 40, whereas the amount of water that can fluctuate is about 1.5.

Therefore, the amount of water held in the can during operation can be considered to be a constant value unique to each boiler system.
Internal thermal energy possessed by the boiler system at the start of the heating period _T1 corresponding to the lower limit steam pressure L
The heating period corresponds to U _L and the upper limit vapor pressure H.
Each of the internal thermal energy U _H possessed by the boiler system at the end of T ₁ is specified to a value unique to each boiler system.

Therefore, based on equation (1), the increase in internal thermal energy (U _H − U _L ) generated in the boiler system as one heating period T ₁ passes is: U _H − U _L = (η・B・It is expressed as H _U )T ₁ + (G _W・I _W )T ₁ −G _S ∫ ^T1 ₀ I _S dt−Q _R・T ₁ …(2).

In reality, the difference between the upper and lower vapor pressure limits H and L is not so large that the enthalpy changes significantly, so for the sake of simplicity, the average enthalpy value I _SM corresponding to the upper and lower vapor pressure limits is calculated, I When _S = I _SM , equation (2) is: U _R − U _L = (η・B・H _U )T ₁ + (G _W・I _W )T ₁ − ( _GS・I _SM )T ₁ −Q _R・T ₁ …(3).

Furthermore, considering the heating period T ₁ ,
Within one heating period T ₁ , water is supplied a number of times according to the amount of evaporation through intermittent control of water supply, which is performed independently of heating control. Therefore, during the water supply period, the amount of water supplied ( On the other hand, during the water supply stop period, water is not supplied at all, and the amount of water supplied (flow rate) flowing into the boiler becomes zero.

However, from a long-term perspective over many heating periods, in an operating boiler system, the average water supply amount (flow rate) supplied by water supply control is in equilibrium with the evaporation amount (flow rate), so the amount of water held in the boiler is approximately It is kept at a constant value.

Therefore, since the water supply amount (flow rate) G _W is equal to the evaporation amount (flow rate) G _S , G _W = G _S (4) holds true.

Then, by substituting equation (4) into equation (3), we get the increment (U _H
−U _L ) is U _H −U _L = (η・B・H _U )T ₁ +( _GS・I _W )T ₁ −( _GS・I _SM )T ₁ −Q _R・T ₁ …( 5).

Next, during the heating stop period, the canned water is not heated;
The first term on the right side of equation (1) becomes zero, and the change in internal thermal energy dU is expressed as dU＝G _W・I _W dt−G _S・I _S・dt−Q _R dt (6), Therefore, the decrease in internal thermal energy (U _L −U _H ) with the passage of one heating stop period T ₂
is expressed as U _L −U _H = (G _W・ I _W ) T ₂ − (G _S・ I _SM ) T ₂ − Q _R T ₂ …(7), and equation (7) is replaced by equation (4). Substituting , we get U _L −U _H = ( _GS・I _W )T ₂ −( _GS・I _SM )T ₂ −Q _R T ₂ …(8).

Here, when formula (8) is added to formula (5), 0=η・B・H _U・T ₁ − {(I _SM −I _W )G _S +Q _R }(T ₁ +T ₂ ) …(9 ) is obtained, and the amount of evaporation G _S is determined from equation (9), G _S =C _B・T ₁ /T ₁ +T ₂ −C _R (10).

However, C _B = η・B・H _U /I _SM −I _W … (10a) C _R = Q _R /I _SM −I _W … (10b) Both are constants unique to each boiler system. .

In this way, the heating period T ₁ and the heating stop period T ₂ of the boiler system are specified to values unique to each boiler system according to the evaporation amount G _S , so that the heating period T ₁ and the heating stop period T ₂ If these are measured and identified, the evaporation amount G _S can be calculated according to the above equation (10).

Then, based on equation (10), the ratio of the heating period T ₁ to the sum of the heating period T ₁ and the heating stop period T ₂
The relationship between T ₁ /T ₁ +T ₂ and the amount of evaporation G _S is illustrated in a graph as shown in Fig. 7. Since the amount of evaporation G _S changes linearly with respect to T ₁ /T ₁ + T ₂ , As in the graphs illustrated in FIGS. 4 and 6, the heating period T ₁ ,
In the region where the heating stop period T ₂ is small, the evaporation amount G _S does not have a steep slope and over the entire change range of T ₁ /T ₁ + T ₂ , that is, the entire change range of the evaporation amount.
The rate of change of is equalized.

As an additional note regarding the graph in Figure 7, straight line A when heat radiation latent loss is small (when C _R is small) is the same as when heat radiation loss is large (when C _R is large).
is located above straight line B.

Next, with reference to FIGS. 2, 3, 5, and 8, the heating period measurement section 7, heating stop period measurement section 8, evaporation amount calculation section 9, constant setting section 10, and display section 11 are The operation will be explained as follows.

FIG. 8 is a flowchart of calculation processing in the evaporation amount calculation section 9.

First _, when the evaporation amount calculation unit 9 starts operating, the microprocessor _9d executes the process shown in FIG. By doing so, the constant C _B ,
After making sure that the heating period T ₁ and heating stop period T ₂ are not read before C _R is set, proceed to the process shown in Fig. 8b, and set the constants C _B and C _R. waits for an interrupt in order to execute the interrupt processing.

When the operator operates the keyboard 10a of the constant setting section 10 and performs a key operation to start the constant setting process, the first interrupt control line 9j becomes "0" and the microprocessor 9d A first interrupt command signal is provided. Then, the microprocessor 9d moves to the step shown in FIG. 8c, and by prohibiting interrupt processing other than the first interrupt processing, the constant C _B
During the execution of the process for setting the C _R , the heating period
T ₁ and the heating stop period T ₂ are not read, and then the process moves to the step shown in FIG. 8d.

Then, an address signal specifying the first input port 9f is sent to the address bus 9b, a control signal is sent to the control bus 9c, and a constant signal S is supplied from the constant setting section 10 to the first input port 9f. Load ₃ . The constant signal _S3 is a digital code generated by key operations for constant setting on the keyboard 10a, and represents the constant C _B. At this time, the constant signal _S3 read from the first input port 9f is transferred to the microprocessor 9d via the data bus 9a and stored in the first register within the microprocessor 9d. Next, the microprocessor 9d moves to the step shown in FIG. 8e, and the above constant C _B
In exactly the same way as the process for setting the constant C _R , a constant signal S' ₃ representing the constant C R as a digital code is transferred and stored in the second register of the microprocessor 9d through the first input port 9f.

After that, the process moves to the step shown in FIG. 8 f, and after canceling the prohibition of the interrupt processing executed in the step shown in FIG. 8 c, the process returns to the step shown in FIG. , heating period _T1 , and heating stop period _T2 .

When intermittent control of the heating device is performed under such conditions, the positive phase output signal of the flip-flop 6b becomes "1" during the heating period _T1 as shown in FIG. 3E. In response to this, AND gate 7b opens only during the heating period to guide the clock pulses from clock pulse oscillator 7a to counter 7c for counting.

Then, as shown in FIG. 3 Ej', when the flip-flop 6b is inverted from "1" to "0", the AND gate 7b is closed and the supply of clock pulses to the counter 7c is cut off, and the counter 7c has the following values:
A digital code representing the heating period T ₁ is generated,
It is output as a heating period signal _S2 .

At this time, at the same time, due to the inversion of the positive phase output signal of the flip-flop 6b from "1" to "0",
The monostable multivibrator 9n is triggered and shifts to a quasi-stable state, sets the second interrupt control line 9k to "0", and provides a second interrupt command signal to the microprocessor 9d.

The microprocessor 9d that has received the second interrupt command signal executes the process shown in FIG.
c, a heating period signal _S2 representing the heating period _T1 outputted by the counter 7c is read from the input port 9g, and in the step shown in FIG. 9d and stored in the third register.

Thereafter, the process returns to the step of FIG. 8b through the return step of FIG. 8j, and waits for an interrupt in order to read the heating stop period _T2 following the heating period _T1 .

Then, the heating period signal outputted by the counter 7c
After S ₂ is loaded into the microprocessor 9d,
The monostable multivibrator 7d was triggered and transitioned to a quasi-stable state by the reversal of the positive phase output signal of the flip-flop 6b from "1" to "0".
returns to a stable state, clears counter 7c,
This is prepared for measurement during the next heating period.

When one heating period ends, Figures 3 and 5
As shown in Ej', the positive phase output signal of the flip-flop 6b is inverted from "1" to "0", the heating stop period _T'2 starts, and the complementary phase output signal of the flip-flop 6b is changed from "0" to "0". 1”.

In response to the complementary output signal of the flip-flop 6b, the AND gate 8b opens and guides the clock pulse from the clock pulse oscillator 7a to the counter 8c only during the heating stop period. The counter 8c operates in the same manner as the counter 7c described above,
As shown in Fig. 5 Em', the flip-flop 6b
At the point when the positive phase output signal of is reversed from "0" to "1" and the heating stop period T' ₂ ends, the heating stop period ends.
A heating stop period signal _S4 representing _T'2 is output.

At the same time, monostable multivibrator 9
p is triggered and shifts to a quasi-stable state, the third interrupt control line 9m is set to "0", and a third interrupt command signal is given to the microprocessor 9d.

The microprocessor 9d that has received the third interrupt command signal then executes the process shown in _{FIG .} is read, and in the step of FIG. 8l, it is transferred and stored in the fourth register in the microprocessor 9d, and then
Proceed to the process shown in Figure m.

In the step m of FIG. 8, the content of the first register stored in the step d is multiplied by the content of the third register stored in the step i to calculate the product;
Furthermore, the contents of the fourth register stored in step l above are added to the contents of the third register to calculate the sum, the above product is divided by the above sum to calculate the quotient, and further, from the above quotient, By subtracting the contents of the second register stored in step e, the calculation T ₁ C _B /T ₁ +T ₂ −C _R is executed, and the calculation result is stored in the fifth register.

The result of this calculation represents the evaporation amount G _S as shown in equation (10).

Subsequently, the microprocessor 9d moves to the step shown in _FIG .
In the return step shown in FIG. 8o, the process returns to the step shown in FIG.

The display unit 11 receives the evaporation amount signal _S5 and displays it visually.

Note that the memory 9e is for storing a program for the series of arithmetic processing described above, and each step of the program is sequentially read out from the memory 9e, transferred to the microprocessor 9d, decoded, and executed as described above. A series of arithmetic processing is executed.

By the way, the theoretical formula expressing the amount of evaporation shown in equation (10) above can be converted into the actually measured formula G _S /G _{S nax} = T ₁ − KT ₂ / T ₁ + T ₂ (11) within the range of realistic values. It can be approximated by

Here, G _{S nax} and K are the maximum evaporation amount and correction coefficient unique to each boiler system, respectively.

Then, for each boiler system, by actually measuring the relationship between the evaporation amount G _S , the heating period T ₁ , and the heating stop period T ₂ and specifying the correction coefficient K, the equation (11) can be used instead of the equation (10). can be adopted.

FIG. 9 extracts and shows the main part of the flowchart of the calculation process when calculating the evaporation amount using the actual measurement formula, that is, the formula (11).
The process in Figure m is replaced by the process in m'.

In the step of FIG. 9 m', the contents of the first register stored in the process of setting the constant C _B in the step of FIG. The product is calculated by multiplying the contents of the fourth register stored in the step of
Calculate the difference by subtracting from the contents of the third register stored in the step in Figure i, and then calculate the sum by adding the contents of the third register and the contents of the fourth register, and calculate the difference. By dividing by the above sum and calculating the quotient, G _S /G _{S nax} is calculated according to equation (11), and the calculation result is stored in the fifth register.

The operations in each of the other steps are exactly the same as shown in the flowchart of FIG.

However, when formula (11) is followed, it is sufficient to perform the constant setting process for only one correction coefficient K, so the step shown in FIG. 8e becomes unnecessary.

In the above configuration of the present invention, the heating period measuring section 7 and the heating stop period measuring section 8 measure the heating period T ₁ and the heating stop period T ₂ for one intermittent control,
One heating period signal S ₂ and one heating stop period signal S ₄ are output, and the amount of evaporation is calculated based on each, but the heating period and heating stop period are measured for multiple intermittent controls. It is also possible to calculate these average values and process them as one heating period signal and one heating stop period signal.

By doing so, it is possible to avoid instantaneous fluctuations in the boiler system, especially variations in the heating period signal and heating stop period signal caused by intermittent control of water supply, and there is the practical benefit of obtaining a more stable and accurate amount of evaporation. .

Further, the heating period measuring section 7 and the heating stop period measuring section 8 are configured to operate in response to the "1" or "0" state of the flip-flop 6b of the heating control section 6, but the present invention is not limited to this. Rather, it is sufficient to measure the period from when the heating device starts until it stops, or from when the heating device stops until it starts, so if you want to start and start the heating device as described above, it is sufficient. The operation state of the heating device as a result of being controlled based on the signal may be directly responsive to the signal for stopping, that is, the "1" or "0" state of the flip-flop 6b, or the operating state of the heating device may be controlled based on the signal. For example, the heating period and the heating stop period may be measured in response to the on/off state of the combustion pump 6'd, the application state of high voltage to the electrode rod 1j, etc.

Furthermore, it should be noted that the first and second comparators 5b and 5c referred to in this specification are not limited to a configuration that is realized as separate and independent hardware; It is also possible to have a configuration that is realized integrally as hardware.

As described above, the present invention is configured to measure the heating period and the heating stop period and calculate the amount of evaporation based on both in a boiler system that performs intermittent control of the heating device. The amount of evaporation can be automatically measured and accurately grasped.

Therefore, according to the present invention, dry heating can be completely prevented by providing backup protection for a control system based on evaporation amount, typically a water supply control system, and it is possible to completely prevent boiler system operation management based on evaporation amount. Additionally, by securing important basic data, damage to equipment, etc. due to carry over and scale growth,
It has the excellent effect of preventing burnout.

Moreover, since the present invention is configured to perform the calculation process of the evaporation amount using both the heating period and the heating stop period, the calculation process based on either the heating period or the heating stop period cannot be performed. As shown in the graphs of FIGS. 4 and ₆ , there is an unavoidable steep change in the _amount of evaporation _.
The tendency of extremely large increases and decreases in the amount of evaporation with respect to increases and decreases in the unit amount during the heating stop period T ₂ is eliminated, and as shown in the graph of FIG. 7, the heating period T ₁ and the heating stop period
The rate of change in the amount of evaporation with respect to the change in the heating period T ₁ and the heating stop period T ₂ can be equalized over the entire range of change in T ₂ , in other words, over the entire range of change in the amount of evaporation.

Therefore, according to the invention, the heating period T ₁ ,
Since the error in the evaporation amount due to the quantization error when measuring the heating stop period T ₂ is equalized over the entire range of change in the evaporation amount, the evaporation amount can be calculated with approximately uniform accuracy over the entire range of change in the evaporation amount. It has the excellent effect of being able to perform measurements and, in turn, achieving highly accurate measurements.

Furthermore, the vapor pressure detection section and the heating control section in the configuration of the present invention are essential components for intermittent control of the heating device.・
Since it is sufficient to add a configuration for processing the stop signal, there is an advantage that the configuration is simple and wasteful, and can be realized at low cost.

[Brief explanation of drawings]

Figure 1A is a block diagram showing the configuration of a small boiler system to which the configuration 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, Figures 2 to 8 relate to embodiments of the invention, Figure 2 is a block diagram showing its configuration, Figure 3, Fig. 5 is a waveform diagram of the main part of the heating control section 6 in Fig. 2, Fig. 4 is a graph showing the relationship between the heating period T ₁ and the evaporation amount G _S , and Fig. 6 is a graph showing the relationship between the heating stop period T ₂ and the evaporation amount. _FIG. 7 is a graph showing the relationship between the ratio of the heating period T ₁ to the sum of the heating period T ₁ and the heating stop period T ₂ and the evaporation amount G _S ,
FIG. 8 is a flowchart showing an example of the procedure of calculation processing in the evaporation amount calculation section 9 in FIG. 2, and FIG. 9 is related to another embodiment of the present invention, 7 is a flowchart showing another example of the procedure of arithmetic processing in section 9. 1... Boiler, 5... Pressure detection section, 5a... Pressure sensor, 5b, 5c... Comparator, 6...
Heating control section, 7... Heating period measuring section, 8... Heating stop period measuring section, 10... Constant setting section, 11...
Display section.

Claims (1)

[Claims] 1 a pressure sensor that outputs a steam pressure signal corresponding to the steam pressure of the boiler; a first comparator that detects that the steam pressure signal is a lower limit set value corresponding to the lower limit steam pressure and outputs a lower limit steam pressure signal; , a second comparator that detects that the vapor pressure signal is the upper limit set value corresponding to the upper limit vapor pressure and outputs the upper limit vapor pressure signal; and in response to the lower limit vapor pressure signal, In a boiler system equipped with heating control means that starts a heating device for heating the boiler and stops the heating device in response to an upper limit steam pressure signal, measures the period from when the heating device starts until it stops. heating period measuring means that outputs the measurement result as a heating period signal; and a heating stop period that measures the period from when the heating device stops until it starts and outputs the measurement result as a heating stop period signal. A boiler system comprising a measuring means and an evaporation amount calculation means for calculating the evaporation amount based on both a heating period signal and a heating stop period signal and outputting the calculation result as an evaporation amount signal. Evaporation measurement device.