JPH04363545A - Hot water supplying apparatus - Google Patents

Abstract

PURPOSE:To prevent an abnormal sound or a back fire, by constructing to correct a rotating speed of a fan when an effective combustion amount becomes smaller than a calculated combustion amount, and supplying the air at the speed of the fan adapted for the effective combustion amount. CONSTITUTION:A combustion amount calculator 12 regulates a proportional valve 7 based on a set temperature input from a temperature setter 10, a water temperature by an input water temperature detector 4 and a flow rate by a flowrate detector 3, and so controls that the temperature of an output hot water temperature detector 5 becomes equal to the set temperature. That is, an input number IP of a gas burner necessary to output hot water of the set temperature is calculated, output to a controller 9, and the opening of the valve 7 is controlled by a proportional valve controller 13. On the other hand, an output calculator 14 receives information of the input water temperature, the output hot water temperature and the flow rate, and calculates an effective output number OP. A comparison/speed setter 15 compares the IP with the OP, outputs a control signal to a fan motor controller 16 when the OP becomes smaller by a predetermined value than the IP, thereby controlling a fan motor 11 to a suitable speed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater equipped with a fan for supplying combustion air to a combustor and means for controlling its rotation speed.

0002

BACKGROUND OF THE INVENTION In conventional water heaters, a combustion amount calculation unit calculates the combustion amount of a gas burner (hereinafter referred to as an input number) so as to dispense hot water at a set temperature based on, for example, the detected incoming water temperature and flow rate. ), a signal indicating the input number is output from the combustion amount calculation section to the proportional valve control circuit, and the proportional valve is controlled by the proportional valve control circuit so that the combustion power of the gas burner is equal to the input number.

On the other hand, the input number outputted from the combustion amount calculation section to the proportional valve control circuit is monitored by the fan motor control circuit, and the rotation of the fan motor is adjusted so that the fan rotation speed corresponds to the input number. controlling the number.

FIG. 6 shows a conventional control method. In FIG. 6, the horizontal axis is the input number IP output from the combustion amount calculation section, and the vertical axis is the actual combustion amount in the gas burner (hereinafter referred to as
It is called the output number. ) OP or fan rotation speed N. The solid line α represents the relationship between the input number IP and the output number OP, the two-dot chain line β represents the straight line of OP=IP (part of which overlaps with the solid line α), and the broken line γ represents the fan rotation speed N. The relationship between N(IP) and the input number IP
each represents. The fan rotation speed characteristic curve γ that determines the fan rotation speed N is experimentally determined in advance with respect to the actual combustion amount of the burner, and therefore the O
It shows a characteristic that is almost parallel to the straight line β of P=IP.

[0005]

[Problem to be Solved by the Invention] However, due to fluctuations in the supply gas pressure (primary gas pressure) in front of the proportional valve and increased pressure loss in the gas passage due to aging, the gas pressure in the gas burner may not be sufficient. It may not be expensive. still,
The gas pressure inside the gas burner is controlled by a proportional valve, but the upper and lower limits are determined by the capacity volume of the proportional valve control circuit.In the above case, even if the opening degree of the proportional valve is increased to the upper limit, the gas burner This prevents the gas pressure inside from increasing.

For this reason, even if the input number increases, the output number of the gas burner does not increase, and the output number may become smaller than the input number, as shown in part A of the solid line α in FIG. be. In this case, even though the output number of the gas burner is not large enough,
Only the fan rotation speed increases unilaterally, and the amount of air supplied by the fan and the amount of combustion no longer match, resulting in combustion problems such as abnormal noises (bleeping noises) and backfires due to excess air. It was occurring.

The present invention has been made in view of the problems of the conventional example described above, and its purpose is to prevent the fan rotation speed from becoming too large compared to the output number of the gas burner. It's about doing.

[0008]

[Means for Solving the Problems] The hot water supply system of the present invention includes a hot water supply path equipped with a heat exchanger, a combustor that heats the heat exchanger, a fan that supplies air to the combustor, and a heat exchanger inlet. an inlet water temperature detector for detecting the inlet water temperature on the side, an outlet hot water temperature detector for detecting the outlet hot water temperature on the heat exchanger outlet side, a flow rate detector for detecting the amount of water flowing through the hot water supply path, and means for setting the outlet hot water temperature. , a combustion amount calculation unit that calculates the combustion amount of the combustor necessary for dispensing hot water at a set hot water temperature, and means for controlling the combustion amount of the combustor based on the calculated combustion amount output from the combustion amount calculation unit. , an output calculation unit that calculates the effective combustion amount of the combustor from the water input temperature, hot water outlet temperature, and water amount, and controls the fan rotation speed based on the calculated combustion amount and compares the effective combustion amount with the calculated combustion amount. The present invention is characterized by comprising means for correcting the fan rotation speed based on the effective combustion amount when the deviation between the two combustion amounts is equal to or greater than a certain value.

[0009]

[Operation] In the present invention, the combustion amount calculation section outputs the calculated combustion amount for dispensing hot water at the set hot water temperature, and the output calculation section outputs the effective combustion amount of the combustor. The fan rotation speed is controlled based on the amount of combustion. Furthermore, when the effective combustion amount and the calculated combustion amount are compared and the deviation between the two combustion amounts exceeds a certain value, the fan rotation speed is corrected based on the effective combustion amount, so the effective combustion amount is the calculated combustion amount. Even if the fan rotation speed is lower than the actual combustion amount, the fan rotation speed can be corrected to a value commensurate with the effective combustion amount so that the fan rotation speed does not become higher. Therefore, it is possible to prevent troubles such as abnormal noise and backfire from occurring due to the fan rotation speed becoming too high.

Moreover, the water heater of the present invention adds an output calculation section to the conventional water heater, which controls the fan rotation speed with the calculated combustion amount based on the relationship between the effective combustion amount and the fan rotation speed, and increases the output. When the effective combustion amount determined by the calculation section is small, the fan rotation speed can be controlled to always be an appropriate rotation speed simply by correcting the fan rotation speed. Therefore, the conventional water heater can be used as is, and by making improvements to the conventional water heater, the fan rotation speed can be controlled to an appropriate rotation speed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 2 shows a schematic configuration diagram of an embodiment of the present invention. The hot water supply path 1 passes through a heat exchanger 2, and on the heat exchanger inlet side there are a flow rate detector 3 that detects the amount of water flowing through the hot water supply path 1, and an inlet water temperature detector that detects the inlet water temperature Tc on the heat exchanger inlet side. 4 is provided, and a hot water temperature detector 5 for detecting hot water temperature Th is provided on the exit side of the heat exchanger. Further, the combustion amount of the gas burner 6 that heats the heat exchanger 2 is adjusted by a proportional valve 7. Combustion air is supplied to the gas burner 6 from a fan 8. The control unit 9 has a hot water temperature setting device 10 for inputting a set value of the outlet water temperature Th, and the input side of the control unit 9 includes a flow rate detector 3, an inlet water temperature detector 4, and an outlet water temperature detector. 5 is connected to the controller 9, and a proportional valve 7 and a fan motor 11 are connected to the output side of the controller 9.

FIG. 1 shows a block diagram of the configuration of the control section 9. As shown in FIG. The control section 9 includes a combustion amount calculation section 12, a proportional valve control circuit 13, an output calculation section 14, and a comparison/rotation speed setting section 1.
5 and a fan motor control circuit 16. The combustion amount calculation unit 12 calculates the set temperature Ts input from the hot water temperature setting device 10 and the inlet water temperature Tc detected by the inlet water temperature detector 4.
The proportional valve 7 is adjusted based on the flow rate q detected by the flow rate detector 3, and feedforward control is performed so that the outlet temperature Th becomes equal to the set temperature Ts. That is, the combustion amount calculation unit 12 calculates the number of gas burners 6 (input number IP) required to discharge hot water at the set temperature Ts from the set temperature Ts, the inlet water temperature Tc, and the flow rate q, and A signal indicating the number IP is sent to the proportional valve control unit 9.
The opening degree of the proportional valve 7 is controlled by the proportional valve control circuit 13.

On the other hand, the output calculation unit 14 stores the outlet water temperature Th detected by the outlet water temperature detector 5 and the inlet water temperature detector 4.
Each information of the incoming water temperature Tc and the flow rate q detected in is input, and the output calculation unit 14 calculates the effective output number OP from these information according to the following equation. OP=(Th-Tc)q/25 This output number OP is compared with the input number IP calculated by the combustion amount calculation part 12/rotation speed setting part 1.
5 is entered.

The comparison/rotation speed setting section 15 compares the input number IP and the output number OP, and
If P-OP<G [However, G is an appropriately determined constant value], the actual gas burner combustion amount is the input number IP
It is determined that there is no significant change, and the fan rotation speed is determined using the fan rotation speed characteristic curve γ as in the conventional case.

On the other hand, in the case of IP-OP≧G, the output number OP of the gas burner 6 is lower than the calculated input number IP, so the comparison/rotation speed setting section 15 outputs a control signal to the fan motor control circuit 16 so that the rotation speed N(IP)-R is smaller than the fan rotation speed N(IP) determined from the fan rotation speed characteristic curve γ by a constant rotation speed R, and N (IP)
- Rotate the fan motor 11 at a rotation speed of R. This prevents the fan 8 rotation speed from becoming too high,
Appropriate fan rotation speed can be obtained.

Furthermore, what is shown in FIG. 4 is a method of controlling the number of rotations N of the fan 8 in another embodiment. In this embodiment, when IP-OP≧G, the fan rotation speed N is fixed to the value N0 when (input number IP)-(output number OP)=G.

[0017] Furthermore, what is shown in FIG.
G, the fan rotation speed is reduced by R, and from there the input number IP and output number O are
This is an embodiment in which the fan rotation speed N is decreased by r each time the difference with P increases by g.

[0018]

Effects of the Invention According to the present invention, when the effective combustion amount becomes smaller than the calculated combustion amount, the fan rotation speed can be corrected. Air can be supplied at the appropriate fan speed, preventing problems such as abnormal noise and backfire. Further, according to the present invention, by improving the conventional water heater, it is possible to manufacture a water heater without any abnormality in fan rotation speed by using the conventional water heater as is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a control unit and its surroundings in an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the hot water supply device same as above.

FIG. 3 is a diagram showing the relationship between the input number, the output number, and the fan rotation speed in the present invention.

FIG. 4 is a diagram showing the relationship between the input number, the output number, and the fan rotation speed in another embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the input number, the output number, and the fan rotation speed in yet another embodiment of the present invention.

FIG. 6 is a diagram showing the relationship between the input number, the output number, and the fan rotation speed in a conventional example.

[Explanation of symbols]

1 Hot water supply path 2 Heat exchanger 3 Flow rate detector 4 Inlet water temperature detector 5　　　　Output water temperature detector 6 Gas burner 7 Proportional valve 8 Fan 9 Control section 10 Water temperature setting section 12　Combustion amount calculation section 13 Proportional valve control circuit 14 Output calculation section 15 Comparison/rotation speed setting section 16 Fan motor control circuit

Claims (1)

[Claims] Claim 1: A hot water supply path equipped with a heat exchanger, a combustor that heats the heat exchanger, a fan that supplies air to the combustor, and an inlet water temperature detector that detects the temperature of inlet water on the inlet side of the heat exchanger. and a hot water temperature detector for detecting the hot water temperature on the exit side of the heat exchanger, a flow rate detector for detecting the amount of water flowing through the hot water supply path, a means for setting the hot water temperature, and a means for dispensing hot water at the set hot water temperature. a combustion amount calculation unit that calculates the required combustion amount of the combustor;
means for controlling the combustion amount of the combustor based on the calculated combustion amount outputted from the combustion amount calculation section; an output calculation section that calculates the effective combustion amount of the combustor from the water input temperature, outlet temperature and water amount; and the calculation section. The fan rotation speed is controlled based on the combustion amount, and the effective combustion amount and the calculated combustion amount are compared, and if the deviation between the two combustion amounts is greater than a certain value, the fan rotation speed is corrected based on the effective combustion amount. A water heating device consisting of means.