JPH025988B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a gas instantaneous water heater, and particularly to a gas instantaneous water heater that limits the temperature of hot water supplied by the amount of gas.

(Prior Art) Conventionally, there have been various structures as a control device for this type of gas instantaneous water heater.
57-49655 is known.

To explain what is shown in FIG. 5, a gas proportional valve 2 for controlling the amount of gas to the burner 3 is installed in the gas supply pipe 4 of the water heater, and a water valve for controlling the amount of water supplied to the heat exchanger 6 is installed in the water supply pipe 5. There are 10 each,
A control device for controlling the gas proportional valve 2 and the water valve includes a temperature setting means 15 and a hot water temperature sensor 30.
and comparison means 31 that compares the set temperature and the hot water temperature and generates an output of a magnitude corresponding to the temperature difference;
The output from the comparing means 31 is amplified and the gas proportional valve 2
an amplifier 3 that adjusts the opening degree of the gas proportional valve 2;
2, until the hot water supply temperature reaches the set temperature when a certain period of time has passed after the start of operation and the magnitude of the output from the comparison means 31 exceeds the magnitude required to fully open the gas proportional valve 2. The water valve control means 33 controls the opening degree of the water valve 10.

Therefore, in the conventional system mentioned above, only the set temperature and hot water temperature are used as factors for controlling gas and water volume.
Since the gas proportional valve and the water valve are controlled according to the difference between the two temperatures, the control is a trial-and-error process, so the accuracy is poor and it takes time to stabilize.

Furthermore, after the start of operation, the water valve control means will not operate until a predetermined period of time, for example 20 to 60 seconds has elapsed, even if the output from the comparison means exceeds the magnitude required to fully open the gas proportional valve. . That is, the hot water temperature does not stabilize until 20 to 60 seconds have passed after the start of operation.

Furthermore, when the input from the comparison means becomes less than the magnitude required to fully open the gas proportional valve, the opening degree of the throttle valve is kept constant. That is, since the throttling operation of the water valve is not stopped until the opening degree of the gas proportional valve becomes slightly smaller than the fully open state, the maximum flow rate at the set temperature cannot be obtained. In other words, the capacity of the water heater cannot be brought out to its limit. There are other inconveniences and inconveniences.

(Problem to be Solved by the Invention) The problem to be solved by the present invention is to add the water amount factor to the control of the gas proportional valve, calculate the required amount of heat, and adjust the gas proportional valve according to the required amount of gas. In addition, by calculating the limit water volume at the set temperature, that is, the maximum water volume that can be covered by fully opening the gas proportional valve, and controlling the water valve to this limit water volume, the accuracy of control is improved. , which enables accurate control immediately after the start of operation and also enables hot water to be supplied at the maximum flow rate at the set temperature.

(Means for Solving the Problems) The technical means taken by the present invention to solve the above problems is that the control device is connected to a water flow sensor that detects the amount of water supplied to the heat exchanger, and a water flow sensor that detects the amount of water supplied to the heat exchanger. A temperature sensor detects the temperature of water supplied to a required heat amount calculation means for changing the temperature, a limit water amount calculation means for calculating the limit water amount at the set temperature based on the set temperature, the detected value of the temperature sensor, and the maximum capacity of the water heater, and the detected value of the water amount sensor and the limit water amount calculation means. Comparison means compares and calculates the value calculated by the means, and if the detected value of the water flow sensor is larger, the opening degree of the water valve is reduced so that the detected value of the water flow sensor approaches the limit water flow. .

The configuration of the present invention will be explained based on FIG.

The water amount sensor and temperature sensor constantly detect the amount and temperature of water supplied to the heat exchanger. The detected value of the water amount sensor is a factor for calculating the required amount of heat, and is input into the required amount of heat calculation means, and the detected value of the temperature sensor is a factor for calculating the required amount of heat, and at the same time, it also serves as a factor for determining the limit amount of water. , is input to the required heat amount calculation means and the limit water amount calculation means. Further, the detected value of the water amount sensor is also input to the comparison means.

The required heat amount calculation means constantly and continuously calculates the required heat amount based on the detected value of each sensor, the set temperature set by the temperature setting means, etc., and outputs an output of a size according to the calculation result to the gas proportional valve. occurs against.

The gas proportional valve changes the opening degree in response to the above output,
Control the amount of gas.

On the other hand, the limit water amount calculation means uses the detected value of the temperature sensor and the set temperature set by the temperature setting means,
Based on the maximum capacity of the water heater, the limit amount of water at the set temperature is calculated. The calculated value of this limit water amount calculation means is input to the comparison means.

The comparison means compares the input limit water amount value and the detected value of the water amount sensor, generates an output to the water valve according to the difference between the two, and opens the water valve so that the detected value of the water amount sensor approaches the limit water amount. change the degree.

The water valve is driven in response to the output from the comparison means, and when the detected value of the water amount sensor exceeds the limit water amount, the opening degree is reduced until the detected value of the water amount sensor matches the limit water amount.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Ru.

In Fig. 2, 1 is a water heater, gas is sent to a burner 3 via a gas supply pipe 4 and burned there, and water enters a heat exchanger 6 via a water supply pipe 5, where it is heated. The hot water is supplied to a faucet 8 through a hot water supply pipe 7.

The gas supply pipe 4 has a former solenoid valve 9 and a gas proportional valve 2.
The former is arranged on the upstream side, and the water supply pipe 5 is provided with a water valve 10 and a temperature sensor 1 sequentially from the upstream side.
1 and a water amount sensor 12 are provided.

These original solenoid valves 9, gas proportional valves 2, water valves 1
0, the temperature sensor 11 and the water amount sensor 12 are electrically connected to a control circuit provided in the control box 13, respectively.
The control circuit 1 detects the temperature of incoming water and sends a signal A, and the water amount sensor 12 detects the amount of incoming water and sends a signal B.
Send to 3.

In addition to the control circuit, the control box 13 is a main switch 14 that turns this device on and off.
and a temperature setting means 15, which are electrically connected to the control circuit. The control circuit uses the set temperature set by the temperature setting means 15, the incoming water temperature detected by the temperature sensor 11, and the water amount sensor 12.
calculates the required amount of heat based on the amount of water detected by the controller, and sends an output signal C having a magnitude corresponding to the calculated value to the gas proportional valve 2.

The gas proportional valve 2 changes its opening degree based on the signal C to increase or decrease the amount of gas sent to the burner 3.

The above required amount of heat is calculated according to the following formula.

F=(Ts−T _IN )×Q×100/η F: Required heat amount, Ts: Set temperature, T _IN : Water temperature, Q:
Water amount, η: Heat exchanger efficiency In addition, the control circuit determines the limit water amount at the set temperature based on the water temperature detected by the water temperature sensor 11, the temperature set by the temperature setting means 15, and the maximum capacity of the water heater 1. At the same time, this limit water amount is compared with the amount of water detected by the water amount sensor 12, and an output of a size according to the comparison result is sent to the signal D.
to send water to valve 10.

The above limit water amount is determined by the following formula.

F _MAX = (Ts-T _IN ) x Q _MAX x 100/η F _MAX : Maximum capacity (heat amount when gas proportional valve is fully open):
Constant Ts: Set temperature T _IN : Water temperature Q _MAX : Limit water flow η: Efficiency of heat exchanger If this is expressed in a drawing, it becomes the curve shown in Figure 3.

The water valve 10 is driven by the above-mentioned signal D to change its opening degree, and when the detected value of the water flow sensor 12 exceeds the limit water flow, the total water flow is throttled, and the hot water exceeding the water limit at the set temperature is Prevent it from flowing into the heat exchanger 6.

An example of the water valve 10 is shown in FIG. The water valve 10 has an inlet 17 and an outlet 18 perpendicular to a valve body 16, and a cylindrical valve body 20 connects the inlet 17 and outlet 18 through an opening 19 formed in the valve body 16 corresponding to the outlet 18. It is watertightly fitted into the communicating flow path 21 via a sealing member 22 so as to block the flow path 21.

The valve body 20 is provided so that its peripheral surface is in sliding contact with the wall surface of the flow path 21 so that it can rotate.
A slit 23 is cut out on the circumferential surface, and an inlet 17 is formed.
The water flowing in from the slit 23 is configured to flow through the valve body 20 and toward the outlet 18 side.

The slit 23 is formed so that its water passage area can be changed by rotation of the valve body 20.

A spindle 24 provided integrally with this valve body 20 is connected to a motor 26 via a reduction gear train 25, and the rotation speed of the motor 26 is reduced by the gear train 25 so that the valve body 20 rotates. .

The motor 26 is rotated or stopped in response to the signal D.

Since the present invention has the above configuration, it has the following advantages.

(1) In response to changes in the limit flow rate due to the set temperature or changes in the limit flow rate due to changes in water temperature, the water supply amount is controlled so that the flow rate does not exceed the limit water flow rate. Once you set the temperature, it will stay at that temperature all year round, and it will never drop.

(2) The temperature display on the control box of conventional gas instantaneous water heaters was vague, such as hot←→warm, but with the water heater of the present invention, once the water temperature is set, the temperature is immediately equal to the water temperature. Since the temperature does not go up or down due to changes in temperature or flow rate, the temperature can be displayed on the temperature setting dial. Therefore, it is easy to use.

(3) The required amount of gas is calculated and the gas amount is controlled, and the limit water amount at the set temperature is calculated, and the water valve is controlled by comparing the limit water amount and the actual water amount, so if the capacity is exceeded. It is possible to immediately judge the flow rate and reduce the flow rate to the limit water volume, and the response is extremely good.

(4) As soon as the water flow sensor detects the water flow, it is possible to calculate the required amount of heat, calculate the limit water flow, and compare the limit water flow with the actual water flow as soon as the hot water supply starts, allowing for accurate hot water supply control as soon as the hot water supply starts. Can be done.

(5) When the flow rate of the water valve exceeds the water limit limit, the opening degree of the water valve is reduced to control the flow rate to the limit water flow rate, so the control is always on the limit curve and hot water is supplied at the maximum flow rate at the set temperature. Can be done.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram explaining the configuration of the present invention, and FIG.
The figure is a schematic configuration diagram of a control device for a gas instantaneous hot water supply system showing an embodiment of the present invention, Figure 3 is a graph diagram showing a limit water flow curve, and Figure 4 is one of the constituent elements of the present invention.
This is a sectional view showing an example of a water valve, partially cut away. FIG. 5 is a schematic configuration diagram showing an example of a conventional control device for a gas water heater. 1...Water boiler, 2...Gas proportional valve, 3...Burner, 5...Water pipe, 6...Heat exchanger, 10...
Water valve, 11...Temperature sensor, 12...Water amount sensor, 15...Temperature setting means.

Claims (1)

[Claims] 1. A gas proportional valve that controls the amount of gas to the burner, a heat exchanger that converts cold water into hot water heated by the combustion of the gas burner, a water valve that controls the amount of water supplied to the heat exchanger, and a heat exchanger. A water flow sensor detects the amount of water supplied to the heat exchanger, a temperature sensor detects the temperature of water supplied to the heat exchanger,
A required heat amount calculating means that calculates the required amount of heat based on the set temperature set by the temperature setting means and the detection value of each sensor, etc., and changes the opening degree of the gas proportional valve according to the calculated value, and the set temperature and the temperature. A limit water amount calculation means for calculating the limit amount of water at the set temperature based on the detected value of the sensor and the maximum capacity of the water heater, and a water amount center detection unit that compares and calculates the detected value of the water amount sensor and the calculated value of the limit water amount calculation means. A control device for a gas instantaneous water heater, comprising a comparing means for reducing the opening degree of a water valve so that the detected value of a water flow sensor approaches a limit water flow when the value is larger.