JPH0560322A - Controller for gas burner - Google Patents

Abstract

PURPOSE:To improve the accuracy of controls by a method wherein a gas control valve and an air damper are controlled corresponding to the loads, and it is checked whether the constant controls of the air-fuel ratio is attained based on the output controlled variables. CONSTITUTION:A controller 30 is composed of a gas controller 31 to which a gas pressure sensor 5 is connected, an air controller 32 to which an air pressure sensor 11 is connected, and an air-fuel ratio controller 33. At the gas controller 31, the manipulated variables of a gas control valve 3 corresponding to the loads are calculated based on gas pressure data, and the valve lift of the control valve 3 is regulated. The valve lift of an air damper 8 is controlled in the similar manner. At the air-fuel ratio controller 33, the gas and air controlled variables respectively calculated by the controllers 32 and 32 based on the load and the pressures are compared with each other to check whether they are at the specified air-fuel ratio, and the results are indicated. Therefore, as the accuracy of the feed rates is improved and the air-fuel ratio is easily kept at the specified ratio, the normal combustion is carried out, and as the air-fuel ratio can always be monitored, the fuel consumption is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a gas burner used in a gas absorption chiller / heater, a gas boiler and the like.

[0002]

2. Description of the Related Art Conventionally, the rotational driving force of a control motor is transmitted to a gas control valve and an air damper by a mechanical linkage mechanism to control the opening and closing of the gas control valve and the air damper independently.

However, in the above conventional gas burner control device, since the opening / closing control is performed by the mechanical linkage mechanism, the flow rate change amount with respect to the opening differs depending on the flow rate characteristic of the valve, and the linear control corresponding to the load is performed. Was difficult.

[0004]

That is, in the conventional gas burner control device, since the flow rate characteristic with respect to the opening of the gas control valve or the air damper is not in a linear relationship, the supply amount of gas or air is accurately determined according to the load. It was difficult to control it, and the solution to this point was an issue.

[0005]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention opens and closes a gas control valve and an air damper respectively by two independent control motors, In a gas burner of proportional control that performs fuel control and air-fuel ratio control, gas control that receives and outputs a gas pressure signal from a gas pressure sensor installed in the gas flow path to a gas control motor and outputs an open / close signal according to the load Device, an air control device that receives and outputs an air pressure signal from an air pressure sensor installed in the air flow path to the air control motor, and outputs and outputs an open / close signal according to the load, and the gas flow rate and air calculated by the gas control device. An air-fuel ratio control device that calculates and outputs a check signal as to whether the air-fuel ratio is controlled to be constant based on the air flow rate calculated by the control device. It by providing a control device for gas burners according to claim was, solves the problems of the aforementioned prior art.

[0006]

[Operation] Since the fluid flow rate and the flow rate resistance have a substantially constant correlation, it is easy to convert the gas pressure or pressure difference as a gas flow rate parameter, and the air pressure or pressure difference can also be used as an air flow rate parameter. Since it is easy to convert, in the gas control device, the pressure signal from the gas pressure sensor is converted into a gas flow rate parameter, and the operation amount of the gas control motor is calculated from this gas flow rate parameter and the gas flow rate corresponding to the load. In the air control device, the air pressure signal from the air pressure sensor is converted into an air flow rate parameter, and the operation amount of the air control motor is calculated from this air flow rate parameter and the air flow rate corresponding to the load, and each control is performed. By outputting a drive signal to the motor to control the opening and closing, it is possible to linearize the load factor. Control becomes possible, and gas control amount and the air control amount is accurately controlled, respectively. Therefore, the supply ratio of air and fuel gas, that is, the air-fuel ratio control is stably performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas burner control device according to the present invention will be described with reference to FIG. 1. In the figure, 1 is a gas burner (main body), 2 is a gas passage, 3 is a gas provided in the gas passage. A control valve, 4 is a gas control motor that is directly connected to open and close the gas control valve, 5 is a gas pressure sensor provided downstream of the gas control valve in the gas flow path 3, and 6 is a blower. Reference numeral 7 is an air flow path, 8 is an air damper provided in the air flow path, 9 is an air control motor directly connected to open and close the air damper, 1
Reference numeral 0 is a wind box, 11 is an air pressure sensor provided in the wind box, and 30 is a control panel, which are arranged as shown in FIG.

The control panel 30 is mainly composed of a gas control device 31, an air control device 32 and an air-fuel ratio control device 33. The gas pressure sensor 5 is connected to the gas control device 31 and the air control device is connected. 32 is the air pressure sensor 1
1 is connected, and pressure data measured by each sensor is input to each of them, and in the gas control device 31, the operation amount of the gas control valve 3 corresponding to the load is based on the gas pressure data input from the gas pressure sensor 5. It calculates and outputs a drive signal to the gas control motor 4 to drive it to adjust the opening of the gas control valve 3. In the air control device 32, the operation amount of the air damper 8 corresponding to the load is calculated. It is designed to perform an operation based on the air pressure data input from the air pressure sensor 11, output a drive signal to the air control motor 9 and drive this, and adjust the air amper 8 to a predetermined opening degree.

Then, the air-fuel ratio control device 33 of the control panel 30
Is calculated by the gas control device 31 and the air control device 32 according to the load and the gas pressure or the air pressure, and output to the gas control motor 4 and the air control amount to the air control mode 9. Is compared and calculated to verify whether or not a predetermined air-fuel ratio is ensured, and when burning at a predetermined air-fuel ratio, for example, a green lamp is lit and displayed on the display unit 34, etc. When the air-fuel ratio is not burning, a red lamp lights up the display.

Next, a specific control example of the control device for the gas burner illustrated in FIG. 1 will be described with reference to FIG. When the signal corresponding to the load A is input to the gas control device 31, the required gas flow rate X ₁ corresponding to this load is calculated, and further,
Based on the gas pressure X _g measured by the gas pressure sensor 5,
For example, the arithmetic expression X ₂ = K ₁ (X _g + A ₁ ) ^1/2 (K ₁ , A
_The gas flow rate X ₂ is calculated by ( ₁ is a constant). And
Gas flow rate X ₂ based on required gas flow rate X ₁ and gas pressure X _g
Based on and, the operation amount of the gas control motor 4 X ₃
Is calculated, and the gas control motor 4 is driven based on the manipulated variable X ₃ to adjust the opening degree X ₄ of the gas control valve 3.

At the same time, when a signal corresponding to the load A is also input to the air control device 32, the required air flow rate Y ₁ corresponding to this load is calculated, and the air pressure Y _a measured by the air pressure sensor 11 is further calculated. Based on the calculation formula Y
_{2 = K 2 (Y a +} A 2) 1/2 (K 2, A 2 is a constant) the air flow Y ₂ is calculated by. Then, the required air flow Y ₁ and manipulated variable Y ₃ of air control motor 9 based on the air flow rate Y ₂ based on air pressure Y _a is calculated,
Based on this manipulated variable Y ₃ , the air control motor 9
Is driven to adjust the opening degree Y _{4 of the} air damper 8.

Then, the comparison calculation between the gas control amount and the air control amount is performed by calculating the gas flow rate X ₂ and the air pressure Y based on the gas pressure X _g.
A comparison calculation is performed using the air flow rate Y ₂ based on a, and the air-fuel ratio check signal S is output. Normally, if the gas control valve 3 and the air damper 8 are opened / closed by a normally measured pressure, a normally calculated operation amount, and a normally driven control motor, the air-fuel ratio falls within a predetermined range. As a matter of course, when an abnormality occurs in any control operation, the air-fuel ratio may exceed the predetermined control range. In such a case, it can be checked easily by verifying the magnitude of the air-fuel ratio check signal S. Therefore, when it exceeds the specified range, an alarm is output and safety is considered if necessary. It is also possible to stop the combustion.

When the opening degree of the gas control valve 3 is changed, the pressure X _{g of the} gas supplied through the gas flow path 2 is changed, so that the gas flow rate is also changed. Therefore, in order to always secure the required gas flow rate X ₁ , a predetermined time (for example, 5 to 5
Every 30 seconds), the gas flow rate X ₂ is calculated based on the gas pressure X _g at each time, and then the required operation amount X ₃ of the gas control motor 4 for obtaining the required gas flow rate X ₁ is calculated. The gas control motor 4 is driven based on the manipulated variable X ₃ to constantly adjust the opening X ₄ of the gas control valve 3. The opening degree of the air damper 8 is also controlled in the same manner as the gas control valve 3.

FIG. 3 is an explanatory view showing the second embodiment,
An orifice 21 for measuring the gas flow rate is provided upstream of the gas control valve 3 in the gas flow path 2.
The differential pressure type gas pressure sensor 5 is arranged so as to communicate with the upstream side and the downstream side, and the orifice 12 for measuring the air flow rate is also formed in the wind box 10 by punching metal or the like. 12 are installed so as to communicate with the upstream and downstream. The other components such as the control panel 30 are the same as those in the above embodiment.

As described above, in the control device using the differential pressure type pressure sensor, since the flow rate can be calculated more accurately from the measured pressure data, the gas control valve 3 can be obtained.
It is possible to further improve the accuracy of adjusting the air-fuel ratio by controlling the opening and closing of the air damper 8 and the air damper 8.

It should be noted that if the calculation formula for calculating the control amount of the control motor by calculating the valve operation amount from the load and the pressure data measured by the pressure sensor is rewritable, it seems that the sensitivity of the pressure sensor is lowered. Even at this time, the flow rate can be accurately grasped to control the air-fuel ratio, and it is also convenient when the type of gas is changed and the air-fuel ratio needs to be changed and controlled.

[0017]

As described above, according to the control device of the gas burner of the present invention, the gas supply amount and the air supply amount are controlled by the control motors respectively installed, and the gas supply amount is also controlled. In the gas control device calculates the operation amount of the gas control valve corresponding to the load based on the gas pressure data input from the gas pressure sensor,
It outputs a drive signal based on the manipulated variable to the gas control motor and drives it to adjust the opening of the gas control valve, so it is possible to perform linear control corresponding to the load and supply gas with high accuracy. Since the air supply amount is also linearly controlled corresponding to the load, the supply accuracy is high. Therefore, the air-fuel ratio is easily controlled to a predetermined ratio and normal combustion is performed. Moreover, it is possible to always check the air-fuel ratio with a check signal, and it is also possible to issue an alarm and stop combustion when it exceeds the control range, so it is used for gas absorption chiller-heater and gas boiler. It is used for controlling the gas burner and has great effects such as improvement of fuel ratio and safety.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example.

FIG. 2 is an explanatory diagram of a control example.

FIG. 3 is an explanatory diagram of another embodiment.

[Explanation of symbols]

 1 Gas Burner (Main Body) 2 Gas Flow Path 3 Gas Control Valve 4 Gas Control Motor 5 Gas Pressure Sensor 6 Blower 7 Air Flow Path 8 Air Damper 9 Air Control Motor 10 Wind Box 11 Air Pressure Sensor 12 Orifice 21 Orifice 30 Control Panel 31 Gas control device 32 Air control device 33 Air-fuel ratio control device 34 Display unit

Claims (1)

[Claims] 1. A gas provided in a gas flow path in a proportional control gas burner that performs fuel control and air-fuel ratio control by opening and closing a gas control valve and an air damper according to loads by two independent control motors. A gas control device that receives and outputs a gas pressure signal from a pressure sensor to a gas control motor, and calculates and outputs an open / close signal according to the load, and an air control signal that receives an air pressure signal from an air pressure sensor installed in the air flow path. An air control device that calculates and outputs an opening / closing signal according to the load on the motor, and whether the air-fuel ratio is controlled to be constant based on the gas flow rate calculated by the gas control device and the air flow rate calculated by the air control device. A control device for a gas burner, comprising: an air-fuel ratio control device that calculates and outputs a check signal.