JPH06168032A - Gas flow rate and air/fuel ratio controller for burner - Google Patents

Abstract

PURPOSE:To hold an air/fuel ratio constant and to stably and execute complete combustion without generating carbon monoxide and soot by providing an opening controller controlling a fuel control valve control motor and an air damper control motor. CONSTITUTION:A fuel flow rate is measured by a flow rate sensor (a), and it is fed back to the opening controller (c). A signal for correcting the characteristic of a fuel control valve (f) is outputted to the fuel control valve control motor (d) and an actual fuel flow rate is controlled as a controlled variable. The opening controller (c) compares the detection value of an oxygen density sensor (b) with a prescribed value, outputs a signal for controlling the opening of an air damper so that the air-fuel ratio is held constant to the air damper control motor (e) and independently operates the fuel control valve (f) and the air damper (g). Plural relations between the opening of the fuel control valve (f) and the flow rate ratio, which are those at the time of opening/closing the valve and/or which correspond to the types of the valves are stored in the opening controller (c), and the opening of the fuel control valve (f) is controlled in accordance with the characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner gas flow rate / air-fuel ratio control device, and more particularly to a burner of an absorption refrigerating machine, which efficiently controls air-fuel ratio during combustion operation. The present invention relates to a burner gas flow rate / air-fuel ratio control device capable of maintaining a constant value and performing stable complete combustion without generating carbon monoxide or soot.

[0002]

2. Description of the Related Art Conventionally, the flow rate of fuel consumed by an absorption chiller-heater or a burner of a boiler is controlled by a mechanical linkage system as shown in FIG. 6. For example, in the case of an absorption chiller, evaporation is performed. A cold water outlet temperature from the vessel is detected by a sensor (not shown), and correspondingly, a signal is output from a control device (not shown) to a control motor (d ') and mechanically driven by the control motor (d'). Fuel control valve (f) and air damper (g) via linkage (h)
Adjust the opening of. However, there is a problem that the air-fuel ratio cannot be made constant in the entire combustion range because of an error caused by the mechanical linkage (h) and the like.
Further, the flow characteristic of the fuel control valve is not linear. For example, when the fuel control valve opening is 50%, the fuel control valve opening is 70% even if the actual fuel flow is 50% of the rated flow. At the time of, the actual fuel flow rate is 90% of the rated flow rate, and thereafter, a state occurs in which the fuel flow rate does not increase greatly even if the control valve is opened. Generally, the cold water control of the absorption chiller uses the fuel control valve opening as the output, so the controllability is poor due to the above reasons, and carbon monoxide is generated because the air-fuel ratio deviates from the predetermined value. The problem arises. The flow rate characteristic of such a fuel control valve is shown in FIG. A to D show flow rate characteristics of different types of fuel control valves.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to efficiently control combustion even in a burner of an absorption chiller having a fuel control valve having the above-mentioned flow rate characteristics and a mechanical linkage. To keep the air-fuel ratio constant,
It is an object of the present invention to provide a gas flow rate / air-fuel ratio control device for a burner that can perform stable complete combustion without generating carbon monoxide or soot.

[0004]

The inventors of the present invention have conducted extensive studies in view of the above problems, and as a result, at the time of combustion operation, the flow rate characteristic of the fuel control valve is corrected by feedback from the flow rate sensor, and the oxygen sensor The present invention has been accomplished by finding that the above problems can be solved by keeping the air-fuel ratio constant by feedback.

According to a first aspect of the present invention, there is provided a flow rate sensor for detecting the flow rate of the fuel supplied to the regenerator burner of the absorption chiller, and a fuel adjustment for adjusting the flow rate of the fuel supplied to the regenerator burner. Valve, a fuel control valve control motor that opens and closes this fuel control valve, an air damper that adjusts the flow rate of combustion air supplied to the regenerator burner, an air damper control motor that opens and closes this air damper, and a regenerator burner. Outputs to the fuel control valve control motor a signal for correcting the flow rate characteristic of the fuel control valve by comparing the detected value of the flow rate sensor and a predetermined value with the oxygen concentration sensor that detects the oxygen concentration in the combustion exhaust gas. An opening control device that outputs a signal for adjusting the opening of the air damper so as to keep the air-fuel ratio constant by comparing the detected value of the oxygen concentration sensor with a predetermined value A gas flow rate and air-fuel ratio control system of the burner, characterized in that it comprises a.

According to a second aspect of the present invention, there is provided a flow rate sensor for detecting the flow rate of the fuel supplied to the regenerator burner of the absorption chiller, and a fuel adjustment for adjusting the flow rate of the fuel supplied to the regenerator burner. Valve, a fuel control valve control motor that opens and closes this fuel control valve, an air damper that adjusts the flow rate of combustion air supplied to the regenerator burner, an air damper control motor that opens and closes this air damper, and a regenerator burner. An oxygen concentration sensor that detects the oxygen concentration in the combustion exhaust gas, and a storage device that stores a plurality of relationships between the opening degree of the fuel control valve and the flow rate ratio corresponding to the valve opening time and the valve closing time and / or the valve type are provided. A signal for controlling the opening of the fuel control valve according to the characteristics stored in the storage device is output to the fuel control valve control motor, and is also stored in the storage device based on the detected value of the flow rate sensor. The opening that sends a signal to the air damper control motor to correct the specified characteristics and to adjust the opening of the air damper to maintain the air-fuel ratio constant by comparing the detected value of the oxygen concentration sensor with a predetermined value. A burner gas flow rate / air-fuel ratio control device comprising a control device.

[0007]

The fuel flow rate is measured by the flow rate sensor (a) and is fed back to the opening control device (c),
A signal for correcting the characteristic of the fuel control valve (f) is sent to the fuel control valve control motor (d) to control the actual fuel flow rate as a control amount. Further, a signal for adjusting the opening degree of the air damper (g) so as to keep the air-fuel ratio constant by comparing the detected value of the oxygen concentration sensor (b) with a predetermined value is sent to the air damper control motor (e), Since the air-fuel ratio can be controlled to be constant by operating the control valve (f) and the air damper (g) independently, stable complete combustion can be achieved. Further, the opening degree control device (c) stores a plurality of relationships between the opening degree and the flow rate ratio of the fuel control valve (f) corresponding to the valve opening time and the valve closing time and / or the type of the valve, and this characteristic is stored in this characteristic. Since the opening of the fuel control valve (f) is controlled accordingly, the same effect as described above can be obtained even when the valve is opened or closed, or when the type of valve is changed. Since the relationship between the opening of the fuel control valve (f) and the flow rate ratio is corrected based on the detection value of the flow rate sensor (a) during the adjustment of f), the opening of the fuel control valve (f) is controlled more accurately. Therefore, the combustion can be further stabilized in combination with the opening control of the air damper (g) based on the detection value of the oxygen concentration sensor (b).

[0008]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. FIG. 1 shows a schematic diagram of the control device of the present invention. The fuel control valve control motor (d) operates the fuel control valve (f) via the mechanical linkage (h), and the air damper control motor (e) operates the air damper (g) via the mechanical linkage (h). To do. In this way, the fuel control valve (f) and the air damper (g) are operated independently.

FIG. 2 shows a system of the control device of the present invention. The fuel flow rate sensor (a) measures the fuel flow rate and feeds it back to the opening control device (c) to output an open signal and a close signal for correcting the characteristics of the fuel control valve (f). The fuel is output to the control motor (d) and conversely receives the opening signal to operate the fuel control valve (f). Further, the air damper control motor (e) outputs an open signal and a close signal for comparing the detected value of the oxygen concentration sensor (b) with a predetermined value to adjust the opening degree of the air damper (g) so as to keep the air-fuel ratio constant. Conversely, the opening signal is received and the air damper (g) is operated. In the memory (m) of the opening control device (c), the relationship between the fuel control valve opening shown in FIG. 4 and the flow rate relation model of the fuel flow rate, the fuel control valve (f) shown in FIG. The air-fuel ratio relational model (g) is stored. For example, the flow rate relational model is modified according to the flowchart shown in FIG. Then, for example, when it is desired to set the fuel control amount to 50% of the rated flow rate, the fuel control valve opening degree is obtained from the flow rate relational model, and the open signal and the close signal are sent to the fuel control valve control motor (d) so as to reach the predetermined opening degree. Is output. At this time, if the flow rate signal from the flow rate sensor (a) is not actually 50% of the rated flow rate, the opening control device (c) further outputs an open / close signal to drive the fuel control valve control motor (d). Adjust and flow sensor (a)
When the detected value of is the rated flow rate, the open / close signal is stopped. The flow rate relational model on the memory (m) is corrected by the control valve opening degree at this time. Then, the opening degree control of the fuel control valve is performed based on the corrected flow rate relational model. The correction of the flow rate relation model is performed, for example, every time the opening degree of the fuel control valve is changed. At the same time, the air damper opening is obtained from the air-fuel ratio model, and an open signal and a close signal are output to the air damper control motor (e) so that the opening becomes a predetermined value. At this time, if the oxygen concentration signal from the oxygen concentration sensor (b) is not a predetermined value, the air damper control motor (e) is adjusted,
The air-fuel ratio relational model on the memory is corrected by the air damper opening degree at this time. The modified air-fuel ratio relational model is stored in the memory like the flow rate relational model for fuel,
The air damper control motor is controlled based on the modified air-fuel ratio relational model.

[0010]

According to the first aspect of the present invention, the gas flow rate / air-fuel ratio control device can efficiently control and maintain a constant air-fuel ratio during the combustion operation of the burner of the absorption refrigerator. Therefore, stable complete combustion can be achieved without generating carbon monoxide or soot. According to the gas flow rate / air-fuel ratio control device of the present invention,
When controlling the opening degree of the fuel control valve, the actual flow rate is obtained from the flow rate sensor and the flow rate characteristic stored in the storage device is corrected, so that the opening degree control of the fuel control valve can be performed that more closely matches the valve characteristic. Therefore, combustion can be further stabilized, and hunting of the valve opening when changing the opening of the fuel control valve can be avoided.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a control device of the present invention.

FIG. 2 is an explanatory diagram of a system of a control device of the present invention.

FIG. 3 is a graph showing a relationship between an air damper opening and a fuel control valve opening.

FIG. 4 is a graph showing a relationship between a flow rate ratio and a fuel control valve opening.

FIG. 5 is a flowchart for performing fuel control valve opening control.

FIG. 6 is a schematic diagram of a conventional controller.

[Explanation of symbols] a flow rate sensor b oxygen sensor c opening control device d fuel control valve control motor d'control motor e air damper control motor f fuel control valve g air damper h mechanical linkage m memory

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location G05B 11/36 503 B 7531-3H 507 H 7531-3H G05D 11/13 B 7314-3H 21/00 A 7314-3H (72) Inventor Haruo Hisaki, 4-1-2 Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka Gas Co., Ltd.

Claims (2)

[Claims] 1. A flow rate sensor for detecting a flow rate of fuel supplied to a regenerator burner of an absorption chiller, a fuel control valve for adjusting a flow rate of fuel supplied to a regenerator burner, and a fuel control valve Fuel control valve control motor that opens and closes, air damper that adjusts the flow rate of combustion air supplied to the regenerator burner, air damper control motor that opens and closes this air damper, and oxygen concentration in combustion exhaust gas from the regenerator burner is detected The oxygen concentration sensor which performs the comparison, outputs a signal for correcting the flow rate characteristic of the fuel control valve by comparing the detection value of the flow rate sensor and a predetermined value, and
An opening control device for outputting a signal to the air damper control motor to adjust the opening of the air damper so as to keep the air-fuel ratio constant by comparing the detected value of the oxygen concentration sensor with a predetermined value. A burner gas flow rate / air-fuel ratio controller. 2. A flow rate sensor for detecting a flow rate of fuel supplied to a regenerator burner of an absorption chiller, a fuel control valve for adjusting a flow rate of fuel supplied to a regenerator burner, and a fuel control valve Fuel control valve control motor that opens and closes, air damper that adjusts the flow rate of combustion air supplied to the regenerator burner, air damper control motor that opens and closes this air damper, and oxygen concentration in combustion exhaust gas from the regenerator burner is detected And an oxygen concentration sensor, and a storage device for storing a plurality of relationships between the opening and closing of the fuel control valve and / or the flow rate ratio corresponding to the valve type A signal for controlling the opening of the fuel control valve according to the determined characteristics is output to the fuel control valve control motor, and the characteristics stored in the storage device are corrected based on the detection value of the flow rate sensor. In addition, an opening control device that outputs a signal for adjusting the opening of the air damper to the air damper control motor by comparing the detected value of the oxygen concentration sensor with a predetermined value to keep the air-fuel ratio constant is provided. Characteristic burner gas flow rate / air-fuel ratio control device.