JPH0289914A - Control device for forced draft type combustion device - Google Patents

Abstract

PURPOSE:To rapidly provide a combustion amount corresponding to a target combustion amount even for a different kind of fuel by a method wherein a blower and a proportional valve feed combustion air and fuel corresponding to a decided combustion amount to a burner in relation to a selected kind of fuel. CONSTITUTION:According to a kind of working gas, control characteristics of each of a blower 12 and a proportional valve 23 are varied. When ignition is detected by means of a flame rod 15, a necessary combustion amount is calculated by a temperature regulation control part 40, and the fundamental voltage value of the blower 12 is decided. A voltage corresponding to an applied voltage obtained by computing and processing the fundamental voltage value according to a kind of gas is applied on the blower 12, which is run at the number of revolutions corresponding to the voltage. When the number of revolutions of the blower 12 is detected, computation and processing for controlling the proportional valve 23 is effected, an energizing current value corresponding to a kind of gas is decided in relation to the proportional valve 23, and on the basis of the current value, the proportional valve 23 is energized. The proportional valve 23 is opened at the opening corresponding to the energizing current, and fuel gas in an amount corresponding to a target combustion amount is fed to a burner 10.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a control device for controlling a blower and a proportional valve in a forced-air combustion device equipped with a blower that supplies combustion air to a burner. The present invention relates to a control device that has been improved to accommodate different fuel types and to obtain a combustion amount corresponding to a target combustion amount.

[Prior Art] Combustion devices such as water heaters and space heaters have different calorific values depending on the type of fuel used. Therefore, for example, when gas is used as fuel, the amount of fuel supplied to obtain the same calorific value differs depending on the type of gas. Further, since the pressure of the supplied gas differs depending on the type of gas, even if the proportional valve that adjusts the gas amount is controlled to the same control amount, the amount of gas supplied to the burner differs.

In combustion equipment, in order to handle multiple gas types without being affected by these differences in fuel types, the gas passages are changed depending on the gas type, and the same control device is used. There is also a method, as in the invention of Japanese Patent Publication No. 57-3844, in which the gas passage is left as is and the gain of the control device is switched in accordance with the type of gas in driving the gas control valve.

[Problems to be Solved by the Invention] However, in a forced-air combustion device in which combustion air is supplied by a blower, particularly in a forced-air combustion device that performs all-air combustion and is equipped with a combustion plate, there are problems depending on the type of gas. If the nozzle etc. are changed and the flame diameter of the combustion plate is changed, the flow rate of the combustion air passing through will change accordingly. Therefore, in order to match the air supplied by the blower to the target combustion amount, it is necessary to change the control characteristics of the blower. In addition, if the proportional valve that adjusts the fuel supply amount is controlled according to the detected rotation speed of the blower, if the control characteristics of the blower are changed, the control characteristics of the proportional valve will change accordingly. As a result, fuel corresponding to each target combustion amount is not supplied, so there is a problem that the target combustion amount cannot be obtained promptly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a forced air combustion apparatus that can quickly obtain a combustion amount corresponding to a target combustion amount even for different fuel types.

Means for Solving the Problem 1 The present invention provides a combustion amount determining means for determining the combustion amount of a burner, and a plurality of controls for controlling a blower that supplies combustion air to the burner in accordance with the fuel type. a blower control means that controls the blower according to the combustion amount determined by the combustion amount determining means; a rotation speed detection means that detects the rotation speed of the blower; and a rotation speed detection means that adjusts the amount of fuel supplied to the burner. having a plurality of control characteristics for controlling the proportional valve corresponding to each of the plurality of control characteristics of the blower control means,
Proportional valve control means for controlling the proportional valve according to the rotational speed detected by the rotational speed detection means, control characteristics of the blower control means, and control characteristics of the proportional valve control means are selected depending on the fuel type, respectively. and control characteristic selection means, and the technical means is to control the blower and the proportional valve, respectively, based on each selected control characteristic.

[Function] In the control device for a forced air combustion device of the present invention, the control characteristics of the blower and the control characteristics of the proportional valve are selected according to the type of fuel used, and the blower is controlled according to the determined combustion amount. , the proportional valve is controlled according to the detected rotational speed of the blower. Here, since the control characteristics of the proportional valve correspond to the control characteristics of the blower, the proportional valve is controlled according to the determined combustion amount.

Therefore, the blower and the proportional valve respectively supply combustion air and fuel to the burner according to the determined combustion amount for the selected fuel type. As a result, the burner obtains the combustion amount determined by the combustion amount determining means.

[Effects of the Invention] In the present invention, even if the types of fuel used are different, combustion air and fuel are supplied according to the determined combustion amount,
Since there is no time lag between each supply amount, the desired combustion amount can be quickly obtained.

[Example] Next, a control device for a forced air combustion apparatus of the present invention will be described based on an example.

In the gas water heater whose outline is shown in FIG. Upon operation, combustion air is supplied from the blower case 12a to the burner case lla. Further, fuel gas is supplied from the nozzle 13, and all-primary air combustion is performed in which combustion is performed using only the primary air supplied by the blower 12, and the combustion gas is discharged from the exhaust port. Above near the burner plate 11 is a sparker 1 which is an ignition device.
4. A flame rod 15 for flame detection and a thermocouple 16 for detecting combustion temperature are provided, respectively.

The fuel pipe 20 that supplies fuel gas to the nozzle 13 includes, in order from the upstream side, a main solenoid valve 21 , a main solenoid valve 22 , and a proportional valve 23 that adjusts the pressure to adjust the amount of fuel supplied to the combustor 10 . and a proportional valve 2 are provided, and the fuel pipe 20 is connected to a proportional valve 2.
3 is branched downstream, and one of the branched fuel pipes 20
is equipped with a solenoid valve 24 for cutting off fuel, and the other is equipped with an orifice 25 for restricting the amount of fuel supplied to the combustor 10.

The water pipe 30 consists of a supply pipe 31 and a hot water supply pipe 31a connected to a water supply source and a hot water supply port (not shown), respectively, and a heat exchanger 32 and a bypass pipe 32a provided in communication between these. A part of the water supplied from 31 is passed through the heat exchanger 32, and the remaining part is sent to the bypass pipe 32.
A by-pass valve 33 is provided at the junction of the heat exchanger 32 and the bypass pipe 32a, and the water heated by the heat exchanger 32 and the water directly guided by the bypass pipe 32a are Adjust the ratio appropriately.

On the other hand, a water flow control valve 34, a water flow sensor 35, and an inlet water temperature thermistor 36 are installed in the supply pipe 31 from the upstream side, a heat exchange thermistor 37 is installed downstream of the heat exchanger 32, and an outlet water temperature thermistor 38 is installed in the hot water supply pipe 31a. The water spray sensors 35 each output a number of pulses corresponding to the number of rotations of an impeller (not shown) rotated by the water flow passing through the supply pipe 31.

The control device 40 is mainly a microcomputer, and as shown in FIG. It is composed of functional parts i43 and water flow control part 44, and further includes a controller 45 operated by the user and a safety circuit (not shown), each of which functions as follows.

The temperature control unit 41 receives a temperature signal obtained from the resistance value of each thermistor arranged in the water pipe 30, a pulse signal from the water flow sensor 35 generated according to the amount of water passing through the water pipe 30, and settings by the controller 45. Based on the temperature
A target combustion amount required for the heat exchanger 32 to heat water is determined, and a basic voltage value to be applied to the blower 12 is determined.

When the ignition control unit 42 receives a water flow signal based on the water amount sensor 35, it performs ignition control in a preset sequence.

The combustion control section 43 includes a blower control section 51 and a rotation speed detection section 5.
2. It has the following functional units: a proportional valve rfII control unit 53, an air-fuel ratio correction unit 54, and a gas type setting unit 55. Each functional unit performs the following ttlfjl-.

The blower control section 51 controls the voltage applied to the blower 12 based on the basic voltage value of the temperature control control section 41 .

Here, the control voltage data of the blower 12 corresponding to the basic voltage value determined by the temperature control controller 41 is stored in the storage device for each gas type, and when the basic voltage value is given, The data is read out by microcomputer processing according to the type of gas used,
A voltage based on the voltage is applied to the blower 12.

Therefore, the blower 12 has the same target combustion ff1Q1-
Corresponding to Q2, for example, city gas (6C), natural gas (
13A>, for propane gas (LPG), as shown by the solid lines A, B, and C in Figure 3, the voltage range varies depending on the gas type: ■1 to v2, ■3 to ■4, and ■5 to ■6. A control voltage is applied, and the HA is operated at different rotation speeds. Note that the content of the arithmetic processing in the blower control section 51 is set by a gas type setting section 55, which will be described later.

The rotation speed detection unit 52 detects the rotation speed of the air blower 8112, and determines a basic current value indicating the current value to be applied to the proportional valve 23 based on the rotation speed.

The proportional valve control unit 53 controls the current flowing to the proportional valve 23 based on the basic current value of the rotation speed detection unit 52. Here, the energizing current data of the proportional valve 23 corresponding to the rotation speed detected by the rotation speed detection section 52 is stored in the storage device for each gas type, and when a basic current value is given, the data corresponding to the rotation speed is stored in the storage device. Data is read out by arithmetic processing by a microcomputer according to the type of gas used, and a current is applied to the proportional valve 23 based on the data. In this calculation process, even if the target combustion amount is the same, the blower 12 is controlled to different rotation speeds depending on the gas type, so the detected rotation speeds differ depending on the gas type. , the amount of gas supplied for the same target combustion amount also differs depending on the type of gas, so the proportional valve 23 has the following characteristics as shown in FIG. ID, E,
As shown in F, different rotational speeds N1 to N2,
Corresponding to the rotation speeds N3 to N4 and rotation speeds N5 to N6, different current values 11 to I2, current values 13 to I4, and current values I5- are set so that the target combustion amount can be obtained, respectively.
I6 is given.

As a result, the proportional valve 23 exhibits an opening degree according to each current value, and the combustor 10 is supplied with an amount of fuel gas that provides the target combustion amount for each gas type. Note that the content of the arithmetic processing in the proportional valve control section 53 is set by a gas type setting section 55, which will be described later.

The air-fuel ratio correction unit 54 calculates an error in the air-fuel ratio based on the output voltage of the thermocouple 16 that is output according to the combustion temperature, corrects the voltage applied to the blower 12 based on the error, and adjusts the amount of combustion air to be supplied. By correcting this, the air-fuel ratio is maintained at an appropriate level. In addition, the blower 1 that changed due to the correction
A signal for correcting the change in the basic current value to the proportional valve 23 corresponding to the rotation speed of 2 is output to the proportional valve control section 53.

The gas type setting section 55 controls the blower control section 51 and the proportional valve control section 53 in order to change each target value of the blower control section 51 and the proportional valve control section 53 according to the type of gas used.
This is the part that sets and changes each control characteristic, that is, the arithmetic expression.

The water flow control M44 controls the bypass valve 33 based on the incoming water temperature.
The opening degree of the water flow control valve 34 is adjusted to restrict the flow of water into the heat exchanger 32 in excess of the heating capacity.

The gas water heater of this embodiment having the above configuration operates as follows.

At the time of shipment from the factory or when installing the gas water heater, the characteristics of the control device 40 are set in advance in the gas type setting section 55 according to the type of gas to be used.

The user sets the hot water temperature using the controller 45,
When a faucet (not shown) is operated, water supplied by the supply pipe 31 passes through the water flow control valve 34 and the water flow sensor 35, flows into the heat exchanger 32 and the bypass pipe 32a, and flows out at the bypass valve 33. The amount is adjusted and flows out from a hot water supply port (not shown) via the hot water supply pipe 31a. Passage of water in the supply pipe 31 is detected by the water amount sensor 35, and the blower 12 starts rotating.

Furthermore, ignition control is started by the ignition control unit 42 based on a signal from the fisheries sensor 35, and spark discharge is performed in the sparker 14. Further, when the original solenoid valve 21 and the main solenoid valve 22 are opened and a predetermined slow ignition current is applied to the proportional valve 23, the fuel gas is ejected from the nozzle 13, mixed with combustion air, and then placed in the burner plate. 11 and is ignited by a sparker 14.

When ignition is detected by the flame rod 15, the necessary combustion amount is calculated in the temperature control section 41, and the air blower 81 is
Twelve base W1 voltage values are determined.

Air blast! A voltage based on an applied voltage obtained by calculating a basic voltage value according to the gas type is applied to the motor 112, and the motor rotates at a rotation speed corresponding to the voltage.

When the rotation speed of the blower 12 is detected, calculation processing is performed to control the proportional valve 23, and the proportional valve 23 is energized according to the type of gas. The it flow value is determined, and the proportional valve 23 is energized based on the current value.

The proportional valve 23 exhibits an opening degree according to the applied current, and
0 is supplied with fuel gas in an amount corresponding to the target combustion amount.

After that, if there is a change in the amount of hot water or the set temperature, the amount of combustion will be changed accordingly.

As described above, in the present invention, the control characteristics of the blower and the proportional valve are changed depending on the type of gas used, so the combustion amount does not change depending on the gas type, and the combustion amount can be adjusted according to the target combustion amount. The amount of combustion can be obtained.

In this embodiment, a gas water heater is shown, but a heater or a cooker equipped with a forced air combustion device may also be used.

Further, the fuel is not limited to gas, but may also be petroleum used in gasification I-.

[Brief Description of the Drawings] Fig. 1 is a functional block diagram showing the 81-function configuration of a control device for a gas water heater according to an embodiment of the present invention, and Fig. 2 shows the configuration of the gas water heater according to the embodiment. Fig. 3 is a characteristic diagram showing the relationship between the target combustion amount and the voltage applied to the blower for indicating the operation of the control device of this embodiment, and Fig. 4 shows the rotation speed of the blower and the current of the proportional valve. FIG. In the figure, 41... Temperature control section (combustion and determination means), 51
... Blower control section (blower control means), 52 ... Rotation speed detection section (rotation speed detection means), 53 ... Proportional valve control section (proportional valve control amniotic membrane), 55 ... Gas type setting section (Control characteristic selection means).

Claims (1)

[Scope of Claims] 1) A combustion amount determining means for determining the combustion amount of the burner, and a plurality of control characteristics for controlling a blower that supplies combustion air to the burner in accordance with the fuel type, A blower control means for controlling the blower according to the combustion amount determined by the combustion amount determining means; a rotation speed detection means for detecting the rotation speed of the blower; and a proportional valve for adjusting the amount of fuel supplied to the burner. Proportional valve control means has a plurality of control characteristics for controlling the plurality of control characteristics respectively corresponding to the plurality of control characteristics of the blower control means, and controls the proportional valve according to the rotation speed detected by the rotation speed detection means; control characteristic selection means for selecting a control characteristic of the blower control means and a control characteristic of the proportional valve control means, respectively, depending on the fuel type; and controlling the blower and the proportional valve based on each selected control characteristic. A control device for a forced air combustion device characterized by controlling each of them.