JPS58106323A - Combustion controller - Google Patents

Abstract

PURPOSE:To improve the combustion efficiency of a combustion controller by controlling the fuel flow rate control valve in response to the sum of the outputs of a proportional integrator and differentiator which inputs an output hot water temperature and the deviation between the hot water temperature and the target temperature and controlling the rotating speed of a fan motor in response to the output of the proportional integrator. CONSTITUTION:In a hot water supplying device, when a cock is opened, a fan motor 12 and a solenoid change over valve 3 are sequentially operated by a combustion sequence control circuit 15. Simultaneously, the deviation between the outputs of a water temperature sensor 11 and a target temperature setter 17 is obtained by a deviation detector 18, and the output of which is applied through a proportional integrator 19 and a differentiator 20 to an adder. Then, the valve opening of a flow rate control valve 5 is adjusted through a valve drive circuit 21 by the sum of both the integrator and differentiator 19, 20. At this time, the output of the integrator 19 is inputted to a fan motor speed control circuit 22, the output of the integratr 19 is discriminated at level in plural stages, thereby operating the switching element 21, and stepwisely varying the rotating speed of the motor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in combustion control devices for combustion appliances such as warm-temperature type combustion equipment.

In recent years, as a thermophilic type, in addition to detecting the flow rate from the heat exchanger, a predetermined control amount is determined by PID calculation from the deviation from the arbitrarily set target temperature, and fuel is supplied according to this control amount. By adjusting the valve opening of the flow control valve installed in the channel and controlling the combustion state in the burner so that it is low combustion when the amount of hot water output is low, and high combustion when the amount of hot water is high, the temperature of the hot water used and the water temperature can be controlled. Some devices are now available that include a combustion control device that operates to maintain the hot water temperature at a target temperature regardless of changes.

In this way, this type of water heater performs feedback control so that the detected temperature matches the set i degree.
Unlike conventionally widely used water boilers, where the combustion state is constant or can only be changed in stages, this system has the great effect of always providing hot water at the desired temperature regardless of changes in water temperature or amount of mold produced. Ministry; Energy oriented.

However, in conventional combustion control devices, only the supply of fuel to the burner is controlled based on the above deviation, and the supply of combustion air is always a constant amount regardless of the combustion state in the burner. The combustion air is transferred to the fan motor.
), this causes excess or deficiency in the supply of combustion air, resulting in poor combustion efficiency, which undermines the significance of introducing PD control with the aim of saving energy.

Therefore, in order to match the air-fuel ratio and improve combustion efficiency, the rotation speed of the fan motor should be controlled using the above-mentioned control amount, that is, the output signal of the PID sieve circuit. It is conceivable to provide a switching means for switching automatically, and a control means for outputting a switching signal to the switching means in accordance with the output level of the PID calculation circuit.

As is well known, the PrD performance circuit receives a step input of the deviation signal shown in Fig. 1(a), and generates a signal proportional to the deviation (A>, a signal integrated with the deviation) as shown in Fig. 1(b). (
B) and a signal (C) obtained by differentiating the change in deviation by 3 to 1 degrees are combined to output a signal (D). Therefore, when adopting such a configuration, the problem is that the differential control means creates a switching signal according to the level of the output signal of the PID logic circuit, so it is natural that A switching signal is also output in response to this differential signal. However, since the fan motor has inertia, the switching signal responsive to this differential signal simply opens and closes the contacts of the switching means, and the switching signal at this time results in wasted contact life. This is expected to have an adverse effect on the lifespan and reliability of the combustion control device itself.

This invention was developed in light of these problems, and its purpose is to make it possible to vary the rotational speed of the fan motor according to the combustion state without adversely affecting the lifespan or reliability of the combustion control device itself. It is to provide combustion control @ position.

In order to achieve the above object, this invention uses a Katamaro sensor and an eye I.
a deviation detection circuit that generates a deviation signal from the Fl temperature setting device; a proportional-integral circuit that performs a proportional-integral circuit based on the output of the deviation detection circuit; and a differentiation circuit that performs a differentiation circuit based on the output of the deviation detection circuit; a valve control circuit that operates in response to the sum of the outputs of the proportional integral circuit and the differential circuit and drives a flow control valve that adjusts the amount of fuel supplied to the burner;
A switching element that changes the rotational speed of a fan motor that supplies combustion air to the bar 1 step by step, and the output of the proportional-integral circuit are level-discriminated into multiple levels, and the switching element is operated with this discrimination output, The present invention is characterized by comprising a fan motor speed control circuit that changes the rotational speed of the motor in steps.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the basic configuration of a separation boiler equipped with a combustion control I device according to the present invention.

In the figure, a fuel supply path to a burner 2 in a warm-temperature main body 1 includes an electromagnetic switching valve 3 which turns on and off the supply of furnace material. an igniter 6 which is provided with a governor 4 and a flow control valve 5 that adjusts the flow of paddy, and which generates an ignition spark in conjunction with the burner 2;
A flame detector 7 is provided to detect whether the ignition is normally ignited by the ignition operation, and an alarm 8 is provided which always issues an alarm if the ignition does not occur normally. A flow switch 10 is installed at the water inlet leading to the heat exchanger 9 to detect the water flow passing through the heat exchanger 9, and a temperature sensor 11 such as a thermistor is installed at the outlet side to detect the outflow temperature. It is provided.

Further, a fan motor 12 is provided in the upper opening of the main body 1, and a wind pressure switch 13 detects that the fan motor 12 has started to rotate.

In addition, a combustion control device 14 that controls the water heater output temperature to be constant has a combustion sequence control circuit 15 and a combustion sequence control circuit 15.
The combustion sequence control circuit 15 includes a 3° electromagnetic switching valve, a 3° igniter, 6. Flame detector7.
Alarm 8. Elements such as the flow switch 10 and the wind pressure switch 13 are connected. In addition, the hot water temperature control circuit 16
Flow control valve 5. Thirst sensor 11 and temperature setting device 17
The fan motor 12 is connected to a combustion sequence control circuit 15 and a hot water temperature control circuit 16, respectively.

6- This hot water temperature control circuit 16 includes a deviation detection circuit 18 which generates a deviation signal from the temperature signal detected by the temperature sensor 11 and the target temperature by the target temperature setting device 17, and a proportional integral circuit which performs a proportional integral circuit based on this deviation signal. The circuit 19, the differential circuit 20 that performs a differential line based on the torrent deviation signal, and operates in response to the sum of the outputs of the proportional-integral circuit 19 and the differential circuit 20, and controls the valve opening of the flow rate control valve 5 to a predetermined value. The valve drive circuit 21 adjusts the opening to the opening degree, and the output of the proportional-integral circuit 19 described in 1-1 is level-discriminated into multiple levels, and the switching element 22 that switches the rotation speed of the fan motor 12 is operated, and the rotation of the fan motor 12 is controlled. The fan motor speed control circuit 23 changes the speed in steps.

FIG. 3 is a diagram showing a specific configuration of the m m i4 control circuit, in which the deviation detection circuit 18 consists of a bridge circuit 11 that includes a temperature sensor 11 and a target temperature setter 17 on one side, and the output of this bridge circuit. is input to the proportional-integral circuit 19 and the differential circuit 20 via the impedance varying circuit 24. And I'11. Example: The output of the integrating circuit 19 is input to the fan motor speed control circuit 23 and the adding circuit 25, and the output of the differentiating circuit 20 is input to the adding circuit 25.

The switching element 22 is composed of a relay, and in this specific embodiment, the rotation speed of the fan motor 12 is changed by switching its contacts into two stages: low speed rotation during low combustion and high speed rotation during high combustion. It is.

Next, the operation of the water heater equipped with the combustion control Il device configured as described above will be explained. Now, when the faucet is opened and water flow is detected by the flow switch 10, the combustion sequence control circuit 15 is activated and the fan motor 12 starts rotating. When the wind pressure caused by the rotation of the fan motor 12 is detected by the wind pressure switch 13, the combustion sequence control circuit 15 opens the electromagnetic switching valve 3. The deviation from the target temperature is determined by the deviation detection circuit 18, and this is output to the proportional integral circuit 19 and the differential circuit 20. Then, the valve drive circuit 21 is determined by the sum of the outputs of the proportional integral circuit 19 and the differential circuit 20. Work.

Since the opening degree of the flow rate control valve 5 is adjusted to an appropriate interval and a predetermined fluent fuel is supplied to the burner 2, the combustion sequence control circuit 15 operates the igniter 6 to generate an ignition spark. As a result, when the burner 2 is properly heated and combustion starts, the flame detector 7 detects this, and if there is an ignition error, the alarm 8 is activated.

on the other hand,)? The motor speed control circuit 23 is a proportional integral circuit 1.
The switching signal is sent to switching element 2 according to the output level of 9.
2, the rotational speed of the fan motor 12 is adjusted and combustion air matching the combustion of the burner 2 is supplied.

As burner 2 ignites normally and enters a normal combustion state,
As the heat exchange in the heat exchanger 9 progresses, hot water is discharged from the faucet, and the temperature of this hot water is detected by the temperature sensor 11, and the deviation from this and the target temperature is determined again by the deviation detection circuit 18. Based on this newly determined a difference, the proportional integral circuit 19
The differential circuit 20 performs predetermined calculations, and the sum of these outputs is 9-.Then, the valve opening of the flow control valve 5 is adjusted so that the deviation is small.

Thereafter, the above-mentioned operation is repeated, and feedback control is performed so that the detected hot water temperature matches the set temperature, and a desired lagoon with a stable temperature is obtained, and combustion air that matches the combustion state is stably supplied. Ru.

As explained in detail above, according to the present invention, combustion air that matches the combustion state can be supplied with a simple configuration without impairing the lifespan or reliability of the combustion control device, thereby greatly increasing the smoking efficiency. A combustion control device that can be improved can be provided.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing deviation signals and PID control waveforms, Fig. 2 is a basic configuration diagram of a water heater equipped with a combustion control device according to the present invention, and Fig. 3 is a specific diagram of a combustion control device. FIG. 2 is a schematic configuration diagram showing an example. 2... Burner 5... Flow rate control valve 11... Temperature sensor 10-12... Fan motor 14... Combustion control device 17. ...Target temperature setting device 18 ...Difference detection circuit 19 ...Proportional-integral circuit 20 ...Differential circuit 22 ...Switching element 23 ...Fan motor'a degree control circuit Patent applicant: Tateishi Electric Co., Ltd.

Claims (1)

[Claims] (1) A deviation detection circuit that generates a deviation signal from the ammaro sensor and the IJl temperature setting device, a proportional-integral circuit that performs proportional-integral calculation based on the output of this deviation detection circuit, and a A differential circuit that performs differential calculations, a valve drive circuit that operates in response to the sum of the outputs of the proportional-integral circuit and the differential circuit, and that drives the flow φ control valve that adjusts the amount of fuel supplied to the burner; A switching element that changes the rotational speed of the fan motor that supplies air in stages, and the output of the proportional-integral circuit are level-discriminated into multiple levels, and the switching element is operated with this discrimination output to adjust the rotational speed of the fan motor. A combustion control device comprising: a fan motor speed control circuit that changes the speed of a fan motor in stages;