JP2601110B2 - Boiler three-position combustion control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a three-position combustion control method for a boiler.

[0002]

2. Description of the Related Art As is well known, in a combustion control apparatus for a hot water boiler, hot water is supplied to a load while maintaining a predetermined temperature by repeatedly controlling each stage of pre-purge, combustion, and post-purge. Among them, the so-called three-position combustion control system uses the combustion stages of high combustion and low combustion (about 50% of high combustion).
This is a combustion control method in which control is performed at three positions of high combustion, low combustion, and stop. An example is shown in FIG. 5, but a thermostat is provided in the boiler to detect the temperature of hot water, and the combustion state is controlled based on the detected value.
The following four set values are set in advance. That is, low combustion cut (H), high combustion cut (L), low combustion start (Hd
H), high combustion start (L-dL), when hot water temperature rises and exceeds the set value (L), shift from high combustion to low combustion,
After that, if the hot water temperature further rises and exceeds the set value (H), it will shift from low combustion to stop.On the other hand, if the hot water temperature falls during the low combustion and drops below the set value (L-dL), low combustion will occur. From high combustion. When the temperature of the hot water drops during the stop and drops below the set value (H-dH), the operation is shifted from the stop to the low combustion. Therefore, the operation is stopped according to the temperature of hot water.
The combustion state is controlled such as low combustion⇔high combustion.

[0003]

However, the above-described combustion control method has the following problems. When the load of equipment using hot water is low, the combustion state is repeated between stop and low combustion, such as stop⇔low combustion. On the other hand, when the load of equipment using hot water is high, the combustion state switches between low combustion and high combustion, such as low combustion and high combustion. Usually, among the set values, the low combustion cut (H) is set to about 83 ° C. and the high combustion cut (L) is set to about 80 ° C. Therefore, when the load is low and high, HL = A deviation of 3 ° C. occurs and the temperature of the supplied hot water is not constant. Further, if the value of L is increased to minimize the value of HL, the start and stop are frequently repeated such as stop → high combustion → low combustion → stop, and the number of starts and stops is increased. If this happens, the burner will fail in a short period of time, or if the load fluctuates greatly, it will not be able to follow the load, causing a response delay, and it will not be possible to supply hot water stably at a constant temperature. Delay for pre-purge time, etc.).

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a boiler provided with a sensor for detecting a state value of an object to be heated in the boiler. A combustion control method for controlling the burner to each of a high combustion, a low combustion and a stop state based on the above, wherein the burner is switched from a high combustion to a low combustion when the detection value T rises to a first set value T1, A first control pattern for switching the burner from low combustion to high combustion when the detected value T falls to the second set value T2, and a burner from low combustion to stop when the detected value T rises to the first set value T1. And setting a second control pattern for switching the burner from stop to low combustion when the detection value T falls to the second set value T2, so that the equipment using the object to be heated of the boiler is in a high load state and a low load state. The first control pattern when in a high load state, and the second control pattern when in a low load state. I have.

[0005]

According to the above configuration, the first control pattern is set when the load is high, and the control pattern is set low when the load is low according to the load state of equipment using the boiler to be heated such as hot water or steam. Can perform combustion control by selecting the second control pattern. There are only two set values for the combustion control, the first set value T1 and the second set value T2, so that the operability is improved and a difference between the high load state and the low load state occurs as in the related art. Instead, when applied to a hot water boiler, it is possible to stably supply hot water at a constant temperature.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram showing an embodiment in which the present invention is applied to a hot water boiler. In the figure, (1) is a boiler, for example, which is constructed by connecting a number of vertical water pipes (not shown) between an upper header and a lower header. (2)
Is a sensor for detecting hot water temperature. (3) is a burner for heating water in the water pipe to make it hot water. The operation / stop of the burner is controlled by the combustion control device (4) based on the detection value T of the sensor (2). The burner (3)
The water heated by the hot water is circulated through the circulation pump (7) and heat exchanger (8) lines connected in series between the hot water outlet (5) and the hot water return port (6). I do. Heat exchanger
In (8), heat exchange between the above-mentioned hot water and cold water supplied from the cistern tank (9) is performed, and the water that has been heat-exchanged into hot water is supplied to the curan (11) through the hot water supply line (10). Is done.

The control method of the burner (3) will be described more specifically. The burner (3) is controlled to a high combustion state, a low combustion state, and a stop state according to a detection value T of the sensor (2). That is, the first set value T1 and the second set value T2 for switching the combustion state are set in advance, and the detected value T
Is increased to the first set value T1, the burner (3) is switched from high combustion to low combustion, and the detected value T is changed to the second set value T2.
A first control pattern ( low combustion / high combustion ) for switching the burner (3) from low combustion to high combustion when the burner (3) is lowered to a low combustion level when the detected value T rises to a first set value T1. And the second control pattern ( stop / low combustion ) for switching the burner (3) from stop to low combustion when the detection value T falls to the second set value T2. The selection is made according to the state. It is determined whether the equipment using the hot water is in a high load state or a low load state. The first control pattern is in a high load state, and the second control pattern is in a low load state. Each pattern is selected (see FIG. 2).

There are various methods for determining whether a device using hot water is in a high load state or a low load state. For example, the following method is used. When the combustion temperature is low, the change gradient of the hot water temperature is detected based on the output signal of the sensor (2), and when the change gradient of the hot water temperature is positive, the load is low, and when the load is negative, Is determined to be in a high load state. Alternatively, the amount of hot water used may be directly detected to determine the load state. Of course, the method of determining the load state is not limited to these methods, and other methods can be applied.

In the embodiment shown in FIG. 1, a hot water temperature is detected by a sensor (2) provided in a hot water supply line (10).
As shown in (5), the temperature of the hot water in the can of the hot water boiler body may be detected, and the burner (3) may be controlled based on the detected temperature. In the figure, (11) indicates a heating device, and hot water circulates between the boiler (1) and the heating device (11). In addition, the present invention can be applied not only to a once-through hot water boiler but also to a hot water boiler of a hot water storage type, and can also be applied to a steam boiler, a heat medium boiler, and the like. As shown in FIG. 4, when the present invention is applied to a steam boiler, the sensor (2) detects the steam pressure (can be the steam temperature) in the can, and performs the same combustion control based on the detected value. To do. In the figure, reference numeral (12) denotes a water level detector, which operates a water supply pump (13) ON-OFF in response to a signal from the water level detector to maintain the water level in the can at a constant level.

[0010]

Since the present invention has the above-described configuration, the first control pattern ( low combustion / high fuel) can be selected according to the load state of equipment using the boiler to be heated, such as hot water or steam.
Baking ) and the second control pattern ( stop⇔low combustion ), and when the load is high, the first control pattern is
When the vehicle is in the low load state, the second control pattern can be selected to perform appropriate combustion control according to the state of the load. At this time, the first control pattern ( low combustion / high fuel
In setting the combustion control and the second control pattern ( stop / low combustion ), the set value for combustion control is the first set value T1.
And the second set value T2, and both control patterns can be set only by setting these two values. Therefore,
Compared with the conventional four-point setting method, the boiler has improved operability and is easy to handle. Also, there is no deviation between high load and low load as in the conventional case,
Hot water at a constant temperature or steam at a constant pressure can be stably supplied.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing one embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a control temperature and a combustion amount in one embodiment of the present invention.

FIG. 3 is a system configuration diagram showing one embodiment of the present invention.

FIG. 4 is a system configuration diagram showing one embodiment of the present invention.

FIG. 5 is a graph showing a conventional relationship between control temperature and combustion amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler 2 Sensor 3 Burner 4 Combustion control device

Claims (3)

(57) [Claims] A boiler (1) is provided with a sensor (2) for detecting a state value of an object to be heated in the boiler, and a burner (3) is set to a high combustion and a low combustion based on a detection value T by the sensor. And a combustion control method for controlling the burner to stop when the detected value T rises to a first set value T1.
(3) is switched from high combustion to low combustion, and a first control pattern for switching the burner (3) from low combustion to high combustion when the detected value T falls to the second set value T2;
The second control is to switch the burner (3) from low combustion to low combustion when the temperature rises to the first set value T1, and to switch the burner (3) from low combustion to stop when the detection value T falls to the second set value T2. A pattern is set, and it is determined whether the apparatus using the object to be heated of the boiler is in a high load state or a low load state. When the apparatus is in a high load state, the first control pattern is The three-position combustion control method for a boiler, wherein each of the second control patterns is selected when the load is low. 2. The method according to claim 1, wherein the boiler (1) is a hot water boiler, and a hot water temperature is detected by a sensor (2). 3. The boiler according to claim 1, wherein the boiler (1) is a steam boiler, and at least one of a steam pressure and a steam temperature in the can is detected by the sensor (2). Position combustion control method.