JPH05240420A - Control device for combustion equipment - Google Patents

Abstract

PURPOSE:To enable electrical exciting current characteristics to the most suit able proportional control valve to be attained depending on the type fuel through switching. CONSTITUTION:A micro-computer 42 has a ROM 42a storing a plurality of groups of data for indicating a current value for a proportional valve 23 for every fuel types in response to a required amount of fuel, a mode setting circuit 47 for use in setting the type of the fuel. The micro-computer 42 reads out the group of data of ROM 42a corresponding to the set state of the mode setting circuit 47 in response to the required amount of combustion and then controls the current value for the proportional valve 23 in response to the read-out group of the data.

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 combustion device, which controls a fuel supply amount to a burner according to a current supplied to a proportional control valve.

[0002]

2. Description of the Related Art In combustion equipment such as water heaters and heaters, the amount of heat generated varies depending on the fuel used, and especially when gas is used as the fuel, the flow rate of fuel supplied to the burner to obtain the same amount of heat generated. However, the proportional control valve that controls the supply amount has to perform control according to each gas type. Therefore, the control circuit of the proportional control valve can be changed for each gas type by using the same circuit (Japanese Patent Publication No. 57-3844).
Also known are those that switch the resistance value of the energizing circuit of the proportional control valve (Japanese Patent Publication No. 60-29852).

[0003]

However, in each of the above inventions, since the current value by the energizing circuit to the proportional control valve is directly changed, the characteristics obtained by switching are as follows.
It is difficult to obtain sufficiently suitable characteristics for each gas type,
There is a problem that it is difficult to obtain optimum characteristics by switching.

An object of the present invention is to provide a control device for a combustion device, which can obtain an optimum current-carrying current characteristic to a proportional control valve according to each fuel by switching.

[0005]

According to the present invention, a proportional control valve, which is provided in a fuel supply passage for supplying fuel to a burner and controls a fuel supply amount to the burner in accordance with an energizing current, is provided by a microcomputer. In a control device for a combustion device that controls according to a required combustion amount that is determined according to a load of a burner, the microcomputer controls the proportional control valve that is set for each type of fuel according to the required combustion amount. A storage unit storing a plurality of data groups indicating current values, a fuel type setting unit for setting the type of the fuel, and the data corresponding to the setting state of the fuel type setting unit according to the required combustion amount And a proportional valve control means for controlling a current value to the proportional control valve based on the data group read by the reading means. And surgical means.

[0006]

According to the present invention, when the required combustion amount is determined by the microcomputer, the data group corresponding to the fuel type set in the fuel type setting means is read out from the plurality of data groups, and the data group is read. Based on this, the current value to the proportional control valve is determined according to the required combustion amount, and the proportional control valve is controlled.
The current value to the proportional control valve is determined by the data group corresponding to the required combustion amount and the fuel type. Therefore, for example, by providing a data group for setting an arithmetic expression that obtains the optimum current value characteristic according to the required combustion amount for each fuel type, the required combustion amount can be adjusted according to the required combustion amount for each fuel type. The optimum current value characteristic can be easily obtained.

Further, the required combustion amount for each fuel type is divided into several ranges, and a plurality of calculations are performed so that the optimum current value characteristic can be obtained for each required combustion amount within each of the divided ranges. By combining a plurality of data groups for setting the equations for each fuel type, it is possible to easily obtain the optimum current value characteristic according to the required combustion amount.

[0008]

According to the present invention, since a plurality of data groups corresponding to the required combustion amount are provided for each fuel type, even if the fuel type setting is switched, the optimum current value characteristic for that fuel type is obtained. Easily obtained. Therefore, by simply switching the fuel type by operating the fuel type setting means,
Optimal fuel supply characteristics can be obtained.

[0009]

Embodiments Next, a gas water heater equipped with a control device for combustion equipment according to the present invention will be described based on embodiments. The gas water heater of this embodiment, which is schematically shown in FIG. 1, includes a combustor 10 and a fuel pipe 20.
And a water pipe 30 and a control device 40. The combustor 10 includes a burner group 11 provided in the water heater case 1.
And a combustion fan 12 for supplying combustion air,
The fuel gas supplied from the nozzle 13 is used for the combustion fan 12
All primary air combustion is performed in which only the primary air supplied by the above is burned, and the combustion gas is discharged from the exhaust port 2. The burner group 11 is a double burner in which a plurality of ribbon burners are arranged in two rows. Above the vicinity of the burner group 11, there are a sparker 14 of an ignition device and a flame rod 1 for flame detection.
5 and a thermocouple 16 are provided respectively.

The fuel pipe 20 is a gas pipe for supplying the fuel gas to the nozzle 13, and a main solenoid valve 21 and a main solenoid valve 22 are arranged in this order from the upstream side thereof, and a proportional valve for adjusting the fuel supply amount to the burner group 11. 23 are provided respectively, and the fuel pipe 20 is branched downstream of the proportional valve 23 to supply the fuel gas to each of the double burners, and one of the branched fuel pipes 20 is connected to the burner group 11. A switching valve 24 is provided to burn only one of them.

The water pipe 30 is a supply pipe 31 and a hot water supply pipe 31 which are respectively connected to a water supply source and a hot water supply port (not shown).
a, a heat exchanger 32 and a bypass pipe 32a provided in communication with each other, part of the water supplied from the supply pipe 31 passes through the heat exchanger 32, and the remaining part passes through the bypass pipe 32a. Is guided to the hot water supply pipe 31a through the heat exchanger 3
A bypass valve 33 is provided at the downstream merging portion of the bypass pipe 32a and the bypass pipe 32a, and appropriately mixes the ratio of the water heated by the heat exchanger 32 and the water directly guided by the bypass pipe 32a.

On the other hand, in the supply pipe 31, from the upstream side, a water amount control valve 34, a water flow sensor 35 and an incoming water temperature thermistor 36.
However, the heat exchange thermistor 37 is provided downstream of the heat exchanger 32.
However, the hot water supply pipe 31a is provided with a hot water outlet temperature thermistor 38, and the hot water supply pipe 31a is provided with a freeze prevention heater (not shown). The bypass valve 33 and the water amount control valve 34 are driven by the respective gad motors, and the water flow sensor 35 has a number corresponding to the number of rotations of an impeller (not shown) rotated by the water flow passing through the supply pipe 31. Output a pulse.

As shown in FIG. 2, the control device 40 includes circuits serving as an interface 41 for exchanging signals with the above-mentioned respective parts provided in the gas water heater, and a microcomputer 42 serving as the center of the control device 40. And a safety circuit 43 and a solenoid valve energizing relay circuit 44 for ensuring safety,
It consists of a power supply unit 45 that supplies power to all of these,
Further, a controller 46 for operating the operation of the gas water heater and a mode setting circuit 47 for presetting the operation mode of the microcomputer 42 are provided.

The interface 41 includes a sparker 14
A high voltage generator for generating a high voltage for performing a spark discharge and a discharge detector for detecting a spark discharge in the sparker 14, a sparker circuit 51, a flame for controlling the air-fuel ratio during combustion. Temperature detection circuit 52 for amplifying the output voltage of the thermocouple 16 according to the temperature of the water, water temperature detection circuit 53 for obtaining respective temperature signals from the resistance values of the thermistors arranged in the water pipe 30, the water amount control valve 34 and the bypass valve. 33 and a gad motor drive circuit 54 for driving each of them based on the resistance value of a potentiometer (not shown) provided for detecting the opening of each valve, and a combustion fan based on a pulse signal transmitted from the microcomputer 42. 12, a fan circuit 55 for driving 12, a proportional valve circuit 56 for energizing the proportional valve 23 for adjusting combustion gas, a communication circuit 5
7, a flame detection circuit 58 for obtaining a flame detection signal by the frame rod 15, a pulse signal based on a pulse signal from the water flow sensor 35 generated according to the amount of water passing through the water pipe 30, while transmitting to the microcomputer 42,
When the amount of water passing through the water pipe 30 exceeds a certain amount,
The switching signal is supplied to the relay circuit power supply 45 of the power supply unit 45.
A water flow circuit 59 is provided for sending to b and transmitting a water flow signal to the safety circuit 43.

The microcomputer 42 constitutes the reading means and the proportional control valve control means of the present invention,
Not only the gas water heater of the present embodiment, but also a custom LSI that is designed so that it can be used for other water heaters with different amounts and sizes of hot water, and has a storage device that stores programs and various data necessary for its operation. Then, predetermined sequence control, combustion amount control and water amount control are performed.

In the combustion amount control and the water amount control, the incoming water temperature thermistor 36, the heat exchange thermistor 37, the controller 4
6. Feed-forward control for controlling the combustion amount and the water amount in advance by each signal from the water flow sensor 35, and feedback control for correcting the combustion amount and the water amount by a signal from the outlet hot water temperature thermistor 38 when a predetermined condition is satisfied. It is carried out.

In the combustion amount control, the combustion fan 12 is controlled on the basis of the combustion amount determined from the signal of each thermistor and the energizing current of the proportional valve 23 is controlled according to the rotation speed. In the present embodiment, in order to design as a device that can also be used for different gas types, a plurality of data groups indicating the current value to the proportional valve 23 preset for each gas type corresponding to the rotation speed of the combustion fan 12 Is provided in the ROM 42a in the microcomputer 42, and the current value to the proportional valve 23 is controlled based on a data group selected by a mode setting circuit 47 described later according to the gas type.

Here, the ROM 42a is provided with a data group showing current value characteristics as shown by solid lines A, B, and C in FIG. 3 for each gas type, and the data groups are sequentially set according to the control state of the microcomputer 42. The current value determined based on the read data group is the control output to the proportional valve circuit 56. As a result, the control device 40 can be used also as a water heater for different gas types, and can provide fine characteristics suitable for each gas type.

The selection and setting for reading the data from the ROM 42a are made according to the gas type required by a mode setting circuit 47 described later, and the setting is made at the time of factory shipment or installation of a gas water heater. It is done at the time of installation by a contractor, and usually once set, there is no need to change it after installation.

The solenoid valve energizing relay circuit 44 is used for the main solenoid valve 2
1, a circuit including a relay for energizing each of the main solenoid valve 22 and the switching valve 24 by a control signal from the microcomputer 42. The power supply unit 45 constantly converts electric power for operating each circuit of the control device 40 into a voltage required for each circuit when a plug (not shown) is inserted into an outlet, and particularly supplies the electric power. Then, for the microcomputer power supply 45a that supplies power to the microcomputer 42 and the relay circuit power supply 45b that supplies power to the solenoid valve energization relay circuit 44, switching for stopping power supply by the energization stop signal from the safety circuit 43 is performed. It has a function to stop the operation of the microcomputer 42, stop the energization of each solenoid valve, and stop the fuel supply.

In the relay circuit power supply 45b for supplying power to the solenoid valve energizing relay circuit 44, the solenoid valves can be energized only when the switching signal from the water flow circuit 59 is transmitted. When the water flow is not detected, the fuel gas is not supplied to the burner group 11, so that there is no fear of being heated. The power supply unit 45 is provided with a temperature fuse and an overheat switch (not shown) in the electric path connected to the commercial power supply to further ensure safety.
The controller 46 is for setting and operating the operating state of the gas water heater, and is provided with a small-capacity microcomputer operated by electric power from the communication circuit 57 and a communication circuit for exchanging signals with the microcomputer 42. , Modulates the setting signal and sends it to the microcomputer 42. The controller 46 also has a display function, which displays the set hot water temperature by a digital number such as a liquid crystal display, and a lamp during combustion in the combustor 10.

The mode setting circuit 47, which is the fuel type setting means of the present invention, sets the operation mode of the microcomputer 42 from the factory according to the type of gas used, the presence or absence of a remote controller, the hot water supply capacity, the exhaust equipment, etc. This is a circuit to be set in advance at the time of shipment or installation of the gas water heater, which is set by the DIP switch connected to each terminal of the custom LSI forming the microcomputer 42.

The gas water heater of the present embodiment having the above construction operates as follows. When the user turns on the operation switch (not shown) of the controller 46 and sets the hot water temperature,
The combustion fan 12 starts rotating. When a water line (not shown) is operated, water flows into the water pipe 30, and the water supplied by the supply pipe 31 passes through the water amount control valve 34 and the water flow sensor 35, and then the heat exchanger 32 and the bypass pipe. Three
2a, the amount of each outflow is adjusted by the bypass valve 33, and it flows out from a hot water supply port (not shown) via the hot water supply pipe 31a.

When a predetermined number or more of pulse signals from the water flow sensor 35 are detected, the microcomputer 42 energizes the high voltage generating portion of the sparker circuit 51 to perform spark discharge to the sparker 14 as ignition operation of the combustor 10. When this is detected, the original solenoid valve 21 and the main solenoid valve 22 are energized by the solenoid valve energization relay circuit 44, the fuel gas is ejected from the nozzle 13 and mixed with the combustion air to burner group 11
And is ignited by the already operating sparker 14.

When the ignition is detected by the frame rod 15, the incoming water temperature thermistor 36, the heat exchange thermistor 3
7. The required combustion amount is calculated based on the detection signals from the thermistors of the hot water temperature thermistor 38 and the water flow sensor 35 and the setting signal from the controller 46, and the combustion fan 12, the proportional valve 23, based on the calculation results. The switching valve 24, the bypass valve 33, and the water amount control valve 34 are controlled. Further, after ignition, the air-fuel ratio correction control is also performed based on the signal from the thermocouple 16, but this control is not performed within a fixed time until the temperature of the thermocouple 16 stabilizes.

After that, when the amount of hot water discharged or the set temperature is changed, the water amount control or the combustion amount control is performed according to the change. In the water amount control, the heat exchanger 32 by the bypass valve 33
The flow rate ratio between the bypass pipe 32a and the bypass pipe 32a is changed.
Further, in changing the combustion amount, the combustion fan 12 is controlled according to the calculated combustion amount, and a current value according to the rotation speed is selected from a plurality of data groups of the ROM 42a selected and set by the mode setting circuit 47. The data group for indicating is read, the current value is determined, and the proportional valve 23 is energized based on the current value.

As described above, according to the control device for a combustion device of the present invention, even if the type of fuel used is different, an appropriate amount of fuel is supplied according to the amount of combustion air supplied by the combustion fan. To be done. In this embodiment, the gas water heater is shown as an embodiment, but it can also be used in a heater or a combustion device using liquid fuel.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas water heater showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a controller of the gas water heater according to the present embodiment.

FIG. 3 is a characteristic diagram showing a current value characteristic of the proportional valve of the present embodiment.

[Explanation of symbols]

11 burner group (burner) 12 combustion fan (blower) 20-fuel pipe (fuel supply path) 23-proportional valve (proportional control valve) 40-control device (combustion device control device) 42-microcomputer (reading means, Proportional control valve control means) 42a ROM (memory means) 47 Mode setting circuit (fuel type setting means)

Claims (1)

[Claims] 1. A proportional control valve, which is provided in a fuel supply passage for supplying fuel to a burner and controls the fuel supply amount to the burner according to a current, is determined by a microcomputer according to the load of the burner. In a control device for a combustion device that controls according to a required combustion amount, the microcomputer is a plurality of data groups indicating a current value to the proportional control valve set for each type of fuel corresponding to the required combustion amount. A read means for reading the data group corresponding to the setting state of the fuel type setting means according to the required combustion amount, and a storage means for storing the fuel type, a fuel type setting means for setting the type of fuel, And a proportional valve control means for controlling a current value to the proportional control valve based on the data group read by the reading means. Location.