JPH0615254Y2 - Blower fan controller for water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a device for controlling the rotational speed of a blower fan that supplies combustion air to a combustor (burner) of a water heater.

[Background technology]

In the conventional water heater, a proportional valve is provided in the gas passage, and the opening of the proportional valve is changed according to the current value of the proportional valve, thereby controlling the amount of gas supplied to the combustor. 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.

[Problems to be solved by the device]

However, the combustion capacity of the combustor may also 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 passage and fluctuations in the gas pressure. At times, the combustor may overpower.

Therefore, the proportional valve current has the maximum value (the maximum opening of the proportional valve)
In a normal operating state where the temperature has not reached the maximum, even if the fan speed may be controlled according to the OA line in FIG. 4,
It is necessary to consider the output over at the time of full opening of the proportional valve and design it so that the air volume has a margin. For this reason,
When the proportional valve current has the maximum value, the fan rotation speed is set to a point B which is larger than the point A, and the fan rotation speed is controlled according to the OB line even in the normal operating state.

Thus, in the conventional case, when the proportional valve is not fully opened, the fan rotation speed shown by the OA line may be used, but the control is performed by the OB line having a larger rotation speed than that. Therefore, there is a problem that the operating energy of the blower fan is wasted, the efficiency is low, and the noise is large.

Therefore, an object of the present invention is to control the blower fan so that it can be operated at an appropriate fan rotation speed under normal operating conditions.

[Means for Solving the Problems]

Therefore, the blower fan control device for the water heater of the present invention provides a heat exchanger, a combustor for heating the heat exchanger, a proportional valve provided in a gas path connected to the combustor, and a combustion air to the combustor. In a water heater consisting of a blower fan to supply, a water amount detecting means for detecting the flow rate of a water channel connected to the heat exchanger, a temperature detecting means for detecting a temperature difference between the incoming water temperature and the outgoing hot water temperature of the heat exchanger, and a 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 signal, this actual output is compared with the specified output, and the proportional valve And a controller for increasing the fan rotation speed of the blower fan when the actual output is larger than the designated output when the opening is reached.

[Action]

In the present invention, when the actual output is larger than the specified output when the proportional valve reaches the maximum opening (when the proportional valve is fully opened), the fan rotation speed is increased.
A large amount of air can be sent when the combustor is overpowered. On the other hand, when the actual output is smaller than the specified output or in the normal operating state where the proportional valve does not reach the maximum opening, the blower fan can be operated at an appropriate fan speed that is not too large, and unnecessary noise is generated. Can be made smaller,
The blowing efficiency of the blowing fan is also improved.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

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

The combustor 6 for heating the heat exchanger 1 is provided with a blower fan 9 for supplying combustion air to the combustor 6.
A rotation speed sensor 20 for detecting the rotation speed of the blower fan 9 is attached to the blower fan 9. In the gas passage 7 for supplying gas to the combustor 6, a proportional valve 8
And a pair of solenoid valves 15 and 16 are provided.

This water heater is controlled by a controller 10 using a microcomputer, and the controller 10 has a structure as shown in FIG. 2, for example. The detection signals from the water amount sensor 3, the incoming water thermistor 4, and the hot water discharge thermistor 5 are input to the arithmetic and control unit 13 (microcomputer). Here, the flow rate w of the water channel 2 and the hot water temperature before and after the heat exchanger 1 The temperature difference t of the incoming water temperature is detected. The arithmetic control unit 13 then outputs the actual output of the combustor 6. And a comparison / determination function for comparing the actual output with a designated output stored in advance. The valve drive unit 19 drives the water amount servo valve 17 to control the amount of water flowing through the water channel 2, and the arithmetic control unit 13 is operated by an input signal from a switch panel (not shown) or the like.
Outputs a control signal to the valve drive unit 19. The valve drive unit 18 controls the opening and closing of the solenoid valves 15 and 16 and 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 operated 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 output over in response to a signal from the arithmetic control unit 13, and in this operating state, the fan rotation number α × i ₀ at the time when the proportional valve current is maximum. The fan rotation speed K (α × i ₀ ) is K (> 1) times, and the blower fan 9 can be operated at a large fan rotation speed. 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 whether or not the proportional valve current has reached the maximum value i ₀ according to the signal from the proportional valve current detection unit 11,
When the proportional valve current reaches the maximum value i ₀ , 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 fixed time elapses, or when the fixed time elapses. A count-up signal is input to the arithmetic control unit 13.

Then, in the normal operation 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 the output of the combustor 6 is over, according to the flowchart shown in FIG. 3, and if the output is over, changes the control mode so as to increase the fan rotation speed. That is, it is determined whether or not the proportional valve current has reached the maximum value i ₀ , and if not, it is determined whether or not the normal operation state is continued and the proportional valve current has reached the maximum value again. If the proportional valve current reaches the maximum value i ₀ (point A in FIG. 4), Tamay 14
Is set, and if it is reset before a fixed time elapses, 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, and when the proportional valve 8 is fully opened, the combustor 6 is Determine if the output is over. If the actual output is less than or equal to the specified output, the fan rotation speed N remains α × i ₀ and the normal operation state is continued. If the actual output signal is larger than the designated output, the fan rotation speed N is shifted K times to become N = Kα × i ₀ , and the air flow rate increases. As a result, the water heater shifts to the state of point B in FIG. 4, and combustion has a margin.

If the proportional valve current drops below the maximum value i ₀ after this, the fan rotation speed may be controlled again along the OA line, or after the fan rotation speed has once shifted to point B, the OB line The fan rotation speed may be controlled along with.

In addition, in the flowchart of FIG.
If the answer is No, you have returned to the previous step,
In the case of No, you may return to the start position of the flowchart.

[Effect of device]

According to the present invention, when the proportional valve is fully opened and the output is over, the fan speed is shifted and increased, so that it is possible to send a larger air flow to the combustor than in the normal operating state. On the other hand, when the proportional valve does not reach the maximum opening or when the output is not over even if it is at the maximum opening, the blower fan can be operated at a low fan rotation speed, and the noise from the blower fan can be reduced. The ventilation efficiency can be improved by reducing the size and operating the blower 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 same controller, FIG. 3 is a flowchart showing a control method of the same, and FIG. 4 is a blower fan of the same. 3 is a graph showing the relationship between the number of revolutions and the combustion ability of the combustor. 1 ... Heat exchanger, 2 ... Water channel 3 ... Water quantity sensor, 4 ... Inlet thermistor 5 ... Outflow thermistor, 6 ... Combustor, 7 ... Gas channel, 8 ... Proportional valve, 9 ... Blower fan, 10 ... Controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyuki Saikai, 32, Akashi-cho, Chuo-ku, Kobe-shi, Hyogo In stock company Noritsu (72) Kazuhiro Kimura, 32, Akashi-cho, Chuo-ku, Kobe, Hyogo Noritsu Co., Ltd. (72) Creator Keiichi Bandai 32, Akashi-cho, Chuo-ku, Kobe-shi, Hyogo In stock company Noritsu

Claims (1)

[Scope of utility model registration request] 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 an outgoing 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 signal from the detection means and the water amount detection signal, and this actual output is compared with the designated output,
A blower fan control device for a water heater, further comprising: a controller that increases the fan rotation speed of the blower fan if the actual output is larger than a specified output when the proportional valve reaches the maximum opening.