JPH0210321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an evaporation amount measuring device for automatically measuring the steam load, that is, the amount of evaporation, in a boiler system, and particularly relates to an evaporation amount measuring device for automatically measuring the steam load, that is, the amount of evaporation, in a boiler system. The present invention relates to an evaporation amount measuring device that measures evaporation amount based on a water supply stop period in intermittent 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 steam 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 this invention is to measure the water supply stop period in intermittent control of the water supply control system without using a flow meter, and to measure the water supply stop period in the intermittent control of the water supply control system, without using a flowmeter, in view of the problems of measuring the amount of evaporation of a boiler system based on the above-mentioned conventional technology. 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 drawbacks and automatically measure the evaporation amount by calculating the evaporation amount.

The configuration of the present invention in accordance with the above object is that a lower limit water level sensor and an upper limit water level sensor are arranged to form a water level detection section, and canned water is supplied to the boiler in response to output signals from each of the upper and lower limit water level sensors. A water supply control unit is provided to start or stop the water supply pump, and when the canned water level drops as steam is consumed and reaches the lower limit water level, the lower limit water level sensor detects this and transmits the lower limit water level signal to the water supply control unit. When the canned water level rises and reaches the upper limit water level with the start of water supply, the upper limit water level sensor detects this and sends an upper limit water level signal to the water supply control unit to start the water supply pump. In a boiler system equipped with an intermittent control water supply control system that stops the water supply, a water supply stop period measurement unit is attached to measure the water supply stop period from when the water supply pump stops until it starts. A quantity calculation section is attached to calculate the quotient by dividing the amount of water specific to each boiler system accumulated by one intermittent control in the water supply control system by the water supply suspension period measured by the water supply suspension period measuring section. , the calculation result is output as an evaporation amount signal.

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 the annular upper header 1d (steam chamber), and the lower portions of the lower header 1c and the water pipe 1b,
Canned water is stored.

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 number of water pipes 1b. From the upper header 1d, a communicating pipe 1l extends outside the wall 1a and connects to the lower header 1.
Connects to c.

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

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 blower stock 1p, and a steam pipe 1q extends from the upper header 1d and communicates with a desired steam load (not shown).

In the configuration of the boiler system described above, when generating steam, the electric motor 1f drives the blower 1g to forcefully feed air into the air passage 1h while applying a high voltage to the electrode rod 1j to generate steam from the tip of the nozzle rod 1i. The injected fuel is ignited and combusted within the combustion chamber 1e. High-temperature combustion gas generated by such combustion enters the hollow part of the water pipe 1b from the lower end of the combustion chamber 1e, passes through it, reaches the flue 1k, and is exhausted. During this time, heat exchange takes place and the canned water in the water pipe 1b is heated and turned into steam, which is then transferred to the upper header 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, The fuel pump 6d is stopped through the control signal line 6c, and combustion is stopped by cutting off the fuel supply, and when the combustion gas is discharged, the electric motor 1f is stopped through the control signal line 6a, thereby cutting off the air blowing from the blower 1g. .

Therefore, even if the combustion is controlled intermittently, the upper header 1
The vapor pressure within d can be maintained at a pressure value between the two preset pressure values as the upper and lower limit vapor pressures.

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 the water supply system, 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, when blowing canned water, use blowing stick 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. 2 and 3.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In comparison with the configuration shown in FIG. 1, the water level in the communicating pipe 1l is equal to the can water level in the water pipe 1b.
is replaced with a simple-shaped communication pipe 1l' that is directly supplied with water by the water supply pump 4.

The water level detection unit 2 includes a lower limit water level probe 2 disposed such that its tip is located at the lower limit water level L of canned water.
a, an upper limit water level probe 2b disposed such that its tip is located at the upper limit water level H of canned water, an underwater electrode 2c buried in water, an AC power source 2d whose one end is connected to the underwater electrode 2c, A first current detector 2e inserted between the other end of the AC power source 2d and the lower limit water level probe 2a, and a second current detector inserted between the other end of the AC power source 2d and the upper limit water level probe 2b. It consists of a vessel 2f.

The water supply control section 3 includes a flip-flop 3 in which the output terminal of the first current detector 2e is connected to its set terminal, and the output terminal of the second current detector 2f is connected to its reset terminal through an inverter 3a.
b, and a relay 3e whose one end is connected to the positive phase output terminal of the flip-flop 3b through a driver 3c, and whose other end is connected to a power source 3d, and the contact 3e' of the relay 3e is connected to the electric motor 4a that drives the water pump 4. is inserted into the power supply line 4b.

The water supply stop period measuring section 7 has a clock pulse oscillator 7a, one input terminal is connected to the output terminal of the clock pulse oscillator 7a, and the other input terminal is connected to the water supply control section 3 (complementary output terminal of the flip-flop 3b). a counter 7c whose output terminal is connected to its input terminal, whose input terminal is connected to the complementary input terminal of the flip-flop 3b, and whose output terminal is connected to the clear terminal of the counter 7c. It consists of a connected monostable multivibrator 7d.

The evaporation amount calculation unit 8 includes a divider 8a whose one input terminal is connected to the output terminal of the counter 7c, whose control terminal is connected to the complementary output terminal of the flip-flop 3b, and whose output terminal is connected to the divider 8a. and a water amount setting device 8b connected to the other input terminal of the water controller.
9 is a display section connected to the evaporation amount calculation section 8a.

FIG. 3 shows changes A in the can water level, that is, the water level in the communication pipe 1l', and the changes in the first and second current detectors 2e and 2.
FIG. 3 is a waveform diagram showing a comparison between output signals B and C of the flip-flop 3b and positive phase output signals D and E of the flip-flop 3b.

Water level detection unit 2 and water supply control unit 3 configured as above
Regarding this, the operation of water supply control will be explained as follows.

Now, when the water level is higher than the lower limit water level L as shown in Fig. 3 Aa, the lower limit water level probe 2a is submerged in water, and conduction is established between it and the underwater electrode 2c through the water, causing alternating current. First current detector 2e, lower limit water level probe 2 for power supply 2d
a. Since a load circuit consisting of the underwater electrode 2c is formed, a current flows to the first current detector 2e, and upon detecting this, the first current detector 2e outputs "1" as shown in FIG. 3Cb. " is output.

Then, when the water level falls and reaches the lower limit water level L as shown in Figure 3 Ac, the tip of the lower limit water level probe 2a leaves the water surface and the load circuit to the AC power source 2d is cut off. The current passing through the current detector 2e becomes zero, and upon detecting this, the first current detector 2e outputs "0" as shown in FIG. 3 Cd.

Upon receiving the inversion of the output signal of the first current detector 2e 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 FIG. 3 De. "0" as shown
to "1". In response to this signal, the driver 3c becomes conductive, the relay 3e is excited, the contact 3e' is closed, and power is supplied to the motor 4a, so that canned water is supplied to the boiler.

Thus, while the flip-flop 3b is at "1", water supply continues and the water level continues to rise as shown in FIG. 3Af.

Eventually, as shown in Fig. 3Ag, when the water level reaches the upper limit water level H, the upper limit water level probe 2b is submerged, and since it has been far from the water surface, it becomes 0 as shown in Fig. 3Bh. The second current detector 2f, which had been outputting "1", now outputs "1", as shown in FIG. 3 Bi.

The inversion of the output signal of the second current detector 2f from "0" to "1" is converted by the inverter 3a into an inversion from "1" to "0" and is supplied to the reset terminal of the flip-flop 3b. ,
Reset this to "0".

Therefore, as shown in FIG. 3Dj, the positive phase output signal of the flip-flop 3b becomes "0", so
Relay 3e becomes de-energized, contact 3e' opens, and water supply stops.

In this way, the period T ₁ (hereinafter referred to as water supply period) from when the water supply pump starts to when it stops is:
The period when the flip-flop 3b is set to "1" is also specified, and furthermore, the period _T2 from when the water supply pump stops until it starts (hereinafter referred to as the water supply stop period) is specified even when the flip-flop 3b becomes "0". It is something that can be specified even during a period of time.

During one water supply stop period in the intermittent control of the water supply pump, the water volume V (Kg ), the water supply stop period is specified as a period during which the amount of water V (Kg) is consumed according to the amount of evaporation (Kg/H).

Therefore, the evaporation amount W is expressed as W [Kg/H]=V [Kg]/T ₂ [H].

Furthermore, the water volume V is the amount of canned water that can be accumulated in the volume between the upper and lower water levels of the boiler, and is a constant that is uniquely determined for each boiler system according to the distance between both water levels. Therefore, it can be seen that the evaporation amount W is inversely proportional to the water supply stop period, in other words, it is proportional to the rate of fall of the water level during the period.

Therefore, after the water supply is stopped, as shown in Figure 3 Ak, the water level will fall again at a rate of decline depending on the amount of evaporation until it reaches the lower limit water level L, as shown in Figure 3 Al. is flipflop 3
b remains at "0" and then reverses to "1" as shown in Fig. 3 Dm, and the water supply stop period T ₂
is formed.

Thereafter, similar operations are repeated until the water level is maintained between the upper limit water level H and the lower limit water level L.

For example, when the amount of evaporation W increases, the rate of decline of the water level increases as shown in Fig. 3Ak', and if now, at the time shown in Fig. 3Ag, at the same time, as shown in Fig. 3Ej Assuming that the water supply is stopped as shown in Figure 3, the flip-flop 3b will be inverted to "1" as shown in Figure 3 Em' at the time shown in Figure 3 Al', so the water supply will be stopped. Outage period
A water supply stop period T ₂ ′ is formed which is shorter than T ₂ .

Next, the operations of the water supply stop period measuring section 7 and the evaporation amount calculating section 8 will be explained as follows.

During the intermittent control of the water supply pump, the positive phase output signal of the flip-flop 3b becomes "0" during the water supply stop period _T2 , for example, as shown in FIG. It becomes "1" during T ₂ . In response to this complementary output signal, the AND gate 7b opens only during the water supply stop period, and the clock pulse from the clock pulse oscillator 7a is guided to the counter 7c to be counted.

Then, as shown in FIG. 3Dm, when the flip-flop 3b is inverted from "0" to "1", its complementary output signal is inverted from "1" to "0", and the AND gate 7b is closed and the counter 7c is inverted. The supply of clock pulses is cut off, and a digital code representing the water supply stop period _T2 is generated in the counter 7c and output as the water supply stop period signal _S1 .

At the same time, the divider 8a receives the inversion of the complementary output signal of the flip-flop 3b from ``1'' to ``0'' (the inversion of the flip-flop 3b from ``0'' to ``1'') at the control terminal. Execute calculation processing.

After the arithmetic processing by the divider 8a is completed, the monostable multivibrator which was triggered and shifted to a metastable state when the complementary output signal of the flip-flop 3b was inverted from "1" to "0" 7d returns to a stable state and sends a clear pulse to the clear terminal of the counter 7c, so the counter 7c is cleared and ready for the next measurement.

During this time, that is, before the counter 7c is cleared, the divider 8a calculates the water amount V set in advance in the water amount setting device 8b, which is a digital switch or the like.
A quotient is calculated by dividing the water amount signal S ₂ representing the amount by the water supply stop period signal S ₁ outputted by the counter 7c, and the calculation result is outputted as the evaporation amount signal S ₃ .

The evaporation amount signal _S3 obtained in this way is V/
Since this is the calculation result of T ₂ , it represents the amount of evaporation, as mentioned above.

The display section 9 receives the evaporation amount signal _S3 from the divider 8a and visually displays it as the evaporation amount W.

In addition, in the above embodiment, the upper and lower limit water level probe 2
Using the conductivity between b, 2a and the underwater electrode 2c,
Although the water level is detected, it is not limited to this, and instead of the configuration of the upper and lower limit water level probes 2b, 2a, etc., an optical system consisting of a light emitting element and a light receiving element arranged opposite each other at positions corresponding to the upper and lower limit water levels. water level sensor,
It is optional to employ an upper and lower limit water level sensor including a magnetic water level sensor that detects a magnetic float with a magnetic sensor disposed at a position corresponding to the upper and lower limit water levels.

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 reaches the upper and lower limit set values.

As in the above configuration, it is possible to realize the upper and lower limit water level sensors in one piece using only one piece of hardware, so the lower limit water level sensor and upper limit water level sensor referred to in this specification are not necessarily realized as separate and independent hardware. It is not limited to the configuration.

Furthermore, in the above embodiment, the water supply stop period measuring section 7
measures the water supply stop period for one water supply and outputs one water supply stop period signal _S1 , and based on this, the evaporation amount calculation unit 8 outputs one evaporation amount signal _S3 , The water supply stop period may be measured for a plurality of water supplies, and the average value thereof may be calculated and processed as one water supply stop period signal _S1 .

By doing so, it is possible to avoid variations in the water supply stop period signal caused by instantaneous fluctuations in the boiler system.
This has the practical benefit of being able to determine the amount of evaporation more stably and accurately.

As described above, the present invention includes a water level detection section and a water supply control section, starts the water supply pump when the canned water level reaches the lower limit water level, and starts the water supply pump when the canned water level reaches the upper limit water level. In a boiler system in which the pump is stopped, a water supply stop period measurement unit and an evaporation amount calculation unit are attached to measure the water supply stop period, and calculate the amount of water accumulated in the boiler even with one intermittent control when the water supply is stopped. Since it is configured to divide by the period and calculate the quotient and output the calculation result as an evaporation amount signal, the evaporation amount in the boiler system 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, the water level detection section and the water supply control section in the configuration of the present invention are essential components for intermittent control of water supply, and they can be used as they are to generate a start/stop signal for the water supply pump obtained from the water supply control section. Since it is sufficient to add a configuration for processing, there is an advantage that the configuration is simple, there is no waste, and it can be realized at low cost.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of a boiler system, Figures 2 and 3 relate to an embodiment of the invention, Figure 2 is a block diagram showing the configuration, and Figure 3 is a block diagram showing the configuration.
The figure is a waveform diagram of the main part. 2...Water level detection unit, 2a...Lower limit water level probe, 2b...Upper limit water level probe, 3...Water supply control unit, 4...Water supply pump, 7...Water supply stop period measurement unit, 8...Evaporation amount calculation unit , 9...display section.

Claims (1)

[Claims] 1. Detecting that the can water level is the lower limit water level,
water level detection means consisting of a lower limit water level sensor that outputs a lower limit water level signal; an upper limit water level sensor that detects that the canned water level is the upper limit water level and outputs an upper limit water level signal; In a boiler system equipped with intermittent control water supply control means that starts a water supply pump that supplies canned water and stops the water supply pump in response to an upper limit water level signal, the period from when the water supply pump stops until it starts. water supply suspension period measuring means for measuring the measurement result as a water supply suspension period signal; and evaporation amount calculation means for calculating the evaporation amount based on the water supply suspension period signal and outputting the calculation result as an evaporation amount signal. The evaporation amount calculation means calculates the quotient by dividing the amount of water that can be accumulated between the upper limit water level and the lower limit water level of the boiler and specified by the distance between the water levels by the water supply stop period. An evaporation amount measuring device for a boiler system, characterized by executing calculations. 2. The evaporation amount measuring device in a boiler system according to claim 1, wherein the water supply suspension period signal from the water supply suspension period measuring means represents an average value of a plurality of water supply suspension periods.