JPH0618023A - Device for controlling blower in hot-water heater - Google Patents

Abstract

PURPOSE:To improve the operation of a blower in efficiency by controlling the number of revolutions of the blower on the basis of the actual output of the burner when the proportional valve is in a full-open state but the actual output falls short. CONSTITUTION:When the opening of a proportional valve 8 provided in a fuel- gas line 7 to a burner 6 has reached the maximum, this maximum opening is detected and the actual output of a burner 6 is determined on the basis of signals from temperature-detective means 4, 5 and a signal from a water-flow- detective means 3. This actual output of the burner 6 is compared with a specified value of output; when it is determined that, whereas the opening of the proportional valve 8 is at its maximum, the actual output is the specified value or less, the number of revolution of the blower 9 is subsequently controlled on the basis of the actual output of the burner 6. This method enables reducing the noise from an unnecessarily high level and improving the condition of the combustion as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water heater combustor (bar).
Device for controlling the rotation speed of a blower fan for supplying combustion air to

[0002]

2. Description of the Related Art In a conventional water heater, a proportional valve is provided in a gas passage, and the opening of the proportional valve is changed according to the current value of the proportional valve to control the amount of gas supplied to the combustor. is doing. On the other hand, the blower fan that supplies combustion air to the combustor detects the proportional valve current and controls the fan speed in proportion to the proportional valve current. That is, when the fan speed is N, the proportional valve current is i, and the proportional constant is β, the fan speed is determined by the relationship of N = β × i.

However, the combustion capacity of the combustor may vary when the proportional valve is fully opened due to various reasons such as the difference in calories of the gas supplied to the gas passages and the fluctuation of the gas pressure. The actual output of the combustor may be less than the specified output when the proportional valve is fully open.

Therefore, the present applicant previously filed Japanese Patent Application No. 2-144.
In No. 98, it is detected that the proportional valve has reached the maximum opening, the actual output of the combustor is obtained based on the detection signals from the temperature detection means and the water amount detection means, and this actual output is compared with the designated output, If the actual output is equal to or less than the specified output when the proportional valve reaches the maximum opening, the fan rotation speed of the blower fan is proportional to the proportional valve current io, the rotation speed N (N = α × io, α).
The fan was operated with a proportional constant.

Such fan control will be described with reference to FIG. In a normal operating state where the proportional valve current does not reach the maximum value (maximum opening of the proportional valve), the fan speed is set to OA.
It may be controlled according to the line, but it is necessary to design considering the actual output shortage when the proportional valve is fully opened. Therefore, when the proportional valve current is at the maximum value, the fan speed is set to point D, which is smaller than point A, and the fan speed is set to O even in normal operating conditions.
You may control according to D line.

[0006]

However, in the above-mentioned conventional example, when the proportional valve has the maximum opening and the actual output is less than the specified output, the rotation speed of the blower fan is the maximum value io of the proportional valve current and the proportional value. Although the engine was operated at a fixed rotational speed N (N = α × io) determined by the constant α (corresponding to the OA line in FIG. 4), this rotational speed is not always the actual output of the combustor. It wasn't.

Therefore, when the proportional valve is at the maximum opening and the actual output is lower than the specified output, the fixed rotational speed N (N
= Α × io), there was a problem in that the supply air became excessive, the combustor generated an abnormal noise, and the flame of the combustor flew off. Further, since the fixed rotation speed N (N = α × io) described above is larger than the proper fan rotation speed, the operating energy of the blower fan is wasted, the blowing efficiency is low, and the noise is large. was there.

Further, when the fan speed is controlled according to the OD line in FIG. 4, unlike the above-mentioned excess supply air, supply air may become insufficient, and the flame during combustion becomes red-yellow and burns, If combustion is continued with this flame, the carbon shining red and yellow becomes soot as it is, and the soot adheres to the combustor and causes incomplete combustion, which is a problem.

Therefore, in the present invention, even if the proportional valve has the maximum opening and the actual output is less than or equal to the specified output, the blower fan can be operated at a fan rotation speed at which an appropriate blown air amount can be obtained. An object of the present invention is to provide a blower fan control device for a water heater, which can reduce required noise, does not deteriorate a combustion state, and improves the blowing efficiency of a blower fan.

[0010]

In the present invention, in order to solve the above-mentioned problems, a heat exchanger, a water amount detecting means for detecting a flow rate of a water channel connected to the heat exchanger, an inlet water temperature and a hot water outlet temperature of the heat exchanger. A temperature detecting means for detecting a temperature difference between the heat exchanger, a combustor for heating the heat exchanger, a proportional valve provided in a gas passage connected to the combustor, and a blower fan for supplying combustion air to the combustor, Detecting that the valve has reached the maximum opening, obtain the actual output of the combustor based on the detection signals from the temperature detection means and the water amount detection means, and compare this actual output with the designated output,
Further, when the proportional valve has reached the maximum opening, and if the actual output is equal to or less than the specified output, a controller for controlling the rotation speed of the blower fan based on the actual output is provided.

[0011]

In the blower fan controller for the water heater, if the actual output of the combustor is less than the specified output when the proportional valve reaches the maximum opening, the rotation speed of the blower fan is controlled based on the actual output. Since it is equipped with a controller, the supply air amount of the blower fan is not excessive or insufficient, and an appropriate supply air amount can be obtained. Therefore, the abnormal noise of the combustor and the flame jump and the flame become red-yellow. However, the combustion state becomes good, the blowing efficiency of the blowing fan improves, and unnecessary noise can be reduced.

[0012]

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

As shown in FIG. 1, the water channel 2 has a heat exchanger 1
Is provided, and a water inlet thermistor 4 for detecting the temperature of the water and a water amount sensor-3 for detecting the water flow rate are provided on the water inlet side of the water channel 2, and the water outlet side of the water channel 2 is provided. Is a hot water discharge thermistor 5 for detecting the temperature of the hot water
A bob valve 17 is provided.

A blower fan 9 for supplying combustion air to the combustor 6 is attached to the combustor 6 which heats the heat exchanger 1. The blower fan 9 is provided with a fan rotation speed of the blower fan 9. A rotation speed sensor-20 for detection is attached. The gas passage 7 for supplying gas to the combustor 6 is provided with a proportional valve 8 and a pair of solenoid valves 15 and 16.

This water heater is controlled by a controller 10 using a micro computer, and the controller 10 has a structure as shown in FIG. 2, for example. The arithmetic and control unit 13 (microcomputer) includes a water amount sensor-3, an incoming water thermistor 4, and an outlet hot water thermistor 5.
Detection and signal is input from, wherein before and after the flow rate w and the heat exchanger 1 of the channel 2 is the hot water temperature T _H and the incoming water temperature T
The temperature difference t of _C is detected. Then, the arithmetic control unit 1
Reference numeral 3 has a calculation function for obtaining the actual output w × t / 25 (number) of the combustor 6 and a comparison / determination function for comparing this actual output with a designated output stored in advance. The valve drive unit 19 drives the water volume servo valve 17 to control the amount of water flowing through the water channel 2. The arithmetic control unit 13 sends the valve drive unit 19 to the valve drive unit 19 by an input signal from a switch panel (not shown) or the like. The control signal is output. The valve drive unit 18 controls the opening / closing of the solenoid valves 15 and 16 and controls the current value of the proportional valve 8 to change the opening degree (gas amount) of the proportional valve 8. The control signal is output to the drive unit 18. The proportional valve current that controls the opening of the proportional valve 8 is detected by the proportional valve current detection unit 11, and the fan rotation speed control unit 12 outputs the proportional valve current i by the signal from the arithmetic control unit 13 in the normal operation state. The blower fan 9 is operating at a fan rotation speed N proportional to (ie, N = α × i; α is a proportional constant). Further, the fan rotation speed control unit 12 can shift to an operating state at the time of insufficient output by a signal from the arithmetic control unit 13, and in this operating state, the rotation calculated by an empirical formula corresponding to the actual output obtained. The blower fan 9 is operated by the number. Therefore, even if the actual output is 97% of the specified output, 9
Even in the case of 5%, the blower fan 9 can be operated at a small fan rotation speed commensurate with the output. Further, the signal from the rotation speed sensor 20 is input to the arithmetic control unit 13, and the fan rotation speed is feedback-controlled by the controller 10. The arithmetic control unit 13 determines that the proportional valve current has the maximum value io according to the signal from the proportional valve current detection unit 11.
It has been determined whether or not the proportional valve current has reached the maximum value i.
When it reaches o, a set signal is output to the timer-14.
The set timer -14 performs a time counting operation, and is reset by a reset signal from the arithmetic control unit 13 if the proportional valve current does not reach the maximum value by the time when a preset constant time elapses, or a predetermined time elapses. Then, the count-up signal is input to the arithmetic control unit 13.

However, in the normal operating state where the proportional valve current does not reach the maximum value, the blower fan 9 is controlled according to N = α × i and according to the OA line in FIG.

On the other hand, the controller 10 detects whether or not the output of the combustor 6 is insufficient according to the flow chart shown in FIG. 3. If the output is insufficient, the fan speed is reduced. Change the control mode as follows. That is, in step 1, the solenoid valves 15 and 16 are opened and the proportional valve 11
To turn on the blower fan 9 to start combustion,
It is determined whether the proportional valve current has reached the maximum value io (S
2) If not, continue the normal operation state and determine again whether the proportional valve current has reached the maximum value. If the proportional valve current reaches the maximum value io (point A in FIG. 4),
The timer-14 is set to determine whether or not a fixed time has passed (S3). If the timer has been reset before the fixed time has passed, the normal operation state is continued.

On the other hand, when a count-up signal is input from the timer -14 to the arithmetic control unit 13 after a certain time has passed, the arithmetic control unit 13 compares the actual output with the designated output (S
4) It is judged whether the combustor 6 is in the output over when the proportional valve 8 is fully opened. If the actual output is less than or equal to the designated output, the fan rotation speed N is controlled along the AC line in FIG.

That is, in step 5, the actual output G when the proportional valve of the rotation speed of the blower fan 9 reaches the maximum opening G
The fan rotation speed Na corresponding to a is changed, and the operation of the blower fan 9 is continued at the changed blower fan rotation speed Na. Here, the relationship between the actual output Ga and the blower fan rotation speed Na will be described with reference to FIG.

That is, as shown in FIG. 5, the fan rotation speed N corresponding to the actual output G is used for control, and the correlation between the actual output G and the fan rotation speed N determines the supply air amount during combustion operation. It is supplied without excess or deficiency, and this correlation is determined in advance by experiments or the like and is stored in the arithmetic control unit 13 in the controller 10.

In this embodiment, this control is performed by detecting that the proportional valve has reached the maximum opening. However, the designated output is calculated from the water amount, the incoming water temperature and the set temperature, and the proportional valve At the same time as outputting the output, the output may be compared with the actual output, and the blower fan may be shifted to the control when the output is insufficient even if the proportional valve is not at the maximum opening. With this configuration, the blower fan having a slow response can reach the target rotation speed as quickly as possible.

[0022]

As described above, according to the present invention, when the proportional valve is fully opened and the output is insufficient, the fan speed is controlled on the basis of the actual output, so that the fan operating speed is lower than in the normal operating state. A small and appropriate amount of air can be sent to the combustor, the combustion state is not deteriorated, noise by the blowing fan can be reduced, and the blowing efficiency can be improved by operating the blowing fan at an appropriate fan speed.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an example of the above controller.

FIG. 3 is a flowchart showing a control method of the above.

FIG. 4 is a graph showing the relationship between the rotation speed of the blower fan and the combustion capacity of the combustor.

FIG. 5 is a diagram showing a relationship between a fan rotation speed N and an actual output (number) G when a combustion output is insufficient.

[Explanation of symbols]

 1 Heat Exchanger 2 Water Channel 3 Water Quantity Sensor 4 Inlet Water Thermistor 5 Outflow Water Thermistor 6 Combustor 7 Gas Channel 8 Proportional Valve 9 Blower Fan 10 Controller

Claims (1)

[Claims] 1. A heat exchanger, a water amount detecting means for detecting a flow rate of a water channel connected to the heat exchanger, a temperature detecting means for detecting a temperature difference between an incoming water temperature and a hot water temperature of the heat exchanger, and a heat exchanger. A combustor that heats the combustor, a proportional valve provided in a gas passage that connects to the combustor, a blower fan that supplies combustion air to the combustor, and detection that the proportional valve has reached the maximum opening, The actual output of the combustor is obtained based on the detection signals from the detection means and the water amount detection means, and this actual output is compared with the designated output,
And a controller for controlling the rotation speed of the blower fan based on the actual output if the actual output is equal to or less than the specified output when the proportional valve reaches the maximum opening. Blower fan controller.