JPH0421101B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water heater that heats and supplies water, and particularly to a water heater that is equipped with a control device that controls the amount of heating such as the amount of combustion depending on the temperature of water entering the water. Concerning vessels.

[Prior Art] In water heaters such as gas-fired water heaters that can freely adjust the amount of heating, the temperature of the water entering the water heater is detected in advance in order to reach the set temperature. The control device performs feed forward control to adjust the amount of combustion as the amount of heating depending on the temperature, and supplies water at a set temperature.

[Problems to be solved by the invention] However, in steady state when the water heater is used continuously and the inlet water temperature is constant, water at the set temperature cannot be supplied by feed forward control based on the inlet water temperature. However, at the beginning of use, the temperature of the water that remains in the water heater is determined by the ambient temperature, and this temperature will be different from the temperature of the water that enters the water heater after water flows through it. There may be cases. Therefore, if the temperature inside the water heater is high and the temperature of the incoming water is low, the temperature of the water supplied from the water heater will be lower than the set temperature, and conversely, if the temperature inside the water heater is low, the temperature of the incoming water will be lower. If the temperature of
There is a problem in that the temperature of the water supplied from the water heater becomes high, and in some cases, it becomes overheated to a temperature higher than the set temperature, which can be extremely dangerous.

The present invention provides a water heater equipped with an inlet water temperature detection means for detecting the inlet water temperature, and a control device that controls the heating amount of the heater based on the inlet water temperature detected by the inlet water temperature detection means. The purpose of the present invention is to provide a safe water heater that can supply water at a set temperature even at the beginning of use and will not be overheated.

[Means for Solving the Problems] The present invention provides a water flow detection means that detects water entering a water heater and generates a water flow signal, and detects the amount of water entering the water heater. a heating means for heating the water entering the water heater; a temperature setting means for setting the temperature of the water heated by the heating means; an inlet water temperature detection means for detecting the temperature of the water to be detected and generating a temperature signal according to the detected temperature; a flow rate detected by the flow rate detection means; a set temperature of the temperature setting means; A water heater comprising a control means for controlling the heating amount of the heating means based on a temperature signal, wherein the control means includes a timer that operates for a predetermined period of time after receiving a water flow signal from the water flow detection means. The technical means is to start reading the temperature signal of the inlet water temperature detecting means after the operation of the timing means is completed, and to start controlling the heating means based on the read temperature signal.

[Function] In the water heater of the present invention, water entering the water heater is detected by the water flow detection means, and a water flow signal is generated by the water flow detection means.

Further, the temperature of water entering the water heater is detected by an incoming water temperature detection means and generated as a temperature signal.

The control means is equipped with a timer that operates for a predetermined time upon receiving the water flow signal, and when the timer finishes operating, the control means reads the temperature signal detected by the inlet water temperature detection means, and reads the temperature signal that has been read. control of the heating means is started based on.

Therefore, control of the heating means by the control means is started based on a temperature signal after a predetermined time has elapsed. Thereafter, the control means controls the heating means based on the temperature signal from the incoming water temperature detection means.

[Effects of the Invention] In the present invention, the heating means is controlled by the control means for the first time after a predetermined period of time has passed after receiving the water flow signal from the water flow detection means. For this reason, the temperature of the water heated by the heating means is adjusted only after the temperature of the water in the water heater has stabilized.
The temperature will never be too high or too low below the set temperature. Therefore, the water heater can be used safely.

[Example] Next, a water heater of the present invention will be described based on an example shown in the drawings.

A combustor case 10 is provided in the water heater case 2 of the gas combustion type water heater 1 shown in FIG. 11 are provided. Further, the combustor case 10 is equipped with a combustion fan 12 using a three-phase Y-connected brushless DC motor, and the burner 11 is forced to burn by the combustion air supplied by the combustion fan 12. It is a blower type combustor, and combustion exhaust gas is exhausted to the outside from an exhaust port 3.

A heat exchanger 13 connected to a water supply pipe 30 is provided above the combustor case 10, and water passing through the interior is heated by heat generated by the burner 11, which is the heating means of the present invention. Further, in the vicinity of the burner 11 in the combustor case 10, a sparker 14 as an ignition device and a flame rod 15 as a flame detection means are provided.

The gas supply pipe 20 includes a source solenoid valve 21, a main solenoid valve 22, which allows fuel gas to pass through when energized from the upstream side.
A governor proportional valve 23 that adjusts the amount of fuel gas supplied by controlling the supply pressure, and a dual burner 11
A switching electromagnetic valve 24 is provided to cut off fuel gas to one of the burners 11 according to the usage state, and supplies fuel gas to the burner 11 described above.

A water drain valve 32 equipped with a water filter 31 is provided at the most upstream portion of the water supply pipe 30, and a water flow control valve 33 operated by a geared motor is provided downstream thereof to adjust the amount of water flowing into the heat exchanger 13. The water flow control valve 33 is equipped with a potentiometer 34 for detecting the opening degree. The temperature of the water whose inflow amount is adjusted by the water amount control valve 33 is detected by the inlet water temperature thermistor 35, which is the temperature detection means of the present invention, provided immediately downstream, and the water amount sensor 36 provided further downstream. The inflow amount is detected and sent to the heat exchanger 13 through the water supply pipe 30.

The gas combustion water heater 1 having the above configuration is controlled by a control device 50.

As shown in FIG. 1, the control device 50 is operated by a power supply section 53 connected to a power cord 51 connected to an outlet of indoor wiring.
is equipped with a main controller 54 and a sub-controller 54a to operate the gas combustion water heater 1.

The control circuit 60 includes a microcomputer 70.
(hereinafter referred to as the CPU 70), there are a sparker circuit 61, a fan circuit 62, a proportional valve circuit 63, a geared motor circuit 64, a position detection circuit 65, and a water amount detection circuit 66, and these circuits are controlled in a prescribed manner by the CPU 70. be exposed.

The fan circuit 62 rotates the combustion fan 12 according to the required combustion amount such as the set water temperature, and
A Hall IC provided in a three-phase Y-connected brushless DC motor detects its rotational speed and sends a detection signal to the CPU 70.

The proportional valve circuit 63 is a circuit that controls the amount of electricity supplied to the governor proportional valve 23 in order to adjust the amount of fuel gas supplied so that combustion in the burner 11 is performed at a desired air-fuel ratio. The amount of energization is controlled based on the rotation speed of the combustion fan 12 except during ignition.

The geared motor circuit 64 is a circuit that drives a geared motor of the water flow control valve 33 for regulating the flow of water into the heat exchanger 13, and opens the water flow control valve 33 according to a control signal.

The position detection circuit 65 is a circuit for analyzing a signal from the potentiometer 34 provided in the water flow control valve 33 to detect its opening degree.

The water amount detection circuit 66 converts a pulse signal from the water amount sensor 36 generated in accordance with the amount of water inflow into a voltage, and outputs it as a voltage indicating the amount of water flowing. Further, the water amount detection circuit 66 is also a water flow detection means of the present invention that generates a water flow signal when a predetermined voltage is output.
The gas combustion type water heater 1 uses the CPU based on the water flow signal.
70, combustion is started in a predetermined sequence.

The CPU 70 is a control means of the present invention, and when the user uses water and obtains a water flow signal based on the water flow sensor 36, the CPU 70 responds to the settings by the main controller 54 and the sub-controller 54a and the output signals of each sensor. to control the amount of combustion.

In this combustion amount control, if the water temperature is read when water is not flowing through the water supply pipe 30, the correct incoming water temperature cannot be obtained. Therefore, in this embodiment, the reading of the water temperature by the incoming water temperature thermistor 35 is carried out by the water amount detection circuit. The CPU 70 is equipped with a timer 71 as a timer so that the water flow signal is detected after a predetermined period of time has elapsed since the water flow signal from the water supply signal 66 is detected.

This means that if the temperature of the water entering the gas combustion water heater 1 and the ambient temperature are significantly different, and the temperature of the water entering the water heater 1 is read at the same time as the water supply signal, the temperature of the water heated by the burner 11 will change. This is because the amount of combustion is calculated only after the inlet water temperature has stabilized, since the temperature may be too low or too high for the set temperature, and if it is particularly high, it is extremely dangerous.

In this embodiment, as shown in FIG.
The operation of 1 is for t (e.g. 0.1 to 5) seconds, and the CPU
70 reads the inlet water temperature by the inlet water temperature thermistor 35 after the operation is completed, and uses the water temperature at that time as a temperature signal. At this time, if the input water temperature read is higher than the set temperature, the operation is not performed, and the operation is started when the set temperature becomes lower than the read temperature by, for example, 2°C.

In addition, control is performed to stop and start operation based on the inlet water temperature obtained from this reading, and when the inlet water temperature is higher than a predetermined temperature, the operation is stopped.
It is operated when the temperature is below a predetermined temperature. In this embodiment, this predetermined temperature is set with a hysteresis characteristic, and the operation is stopped when the inlet water temperature is 55°C or higher.
Operation starts when the temperature drops below 50℃.

Next, the gas combustion type water heater 1 having the above configuration will be described.
The operation will be explained based on FIGS. 3 and 4.

When the user closes a power switch (not shown), sets the water temperature, and starts water flow, water flows into the water supply pipe 30, the water amount sensor 36 is activated, and its signal is sent to the water amount detection circuit 66.

The CPU 70 determines whether or not there is a water flow signal based on the output voltage of the water amount detection circuit 66 (step
100), if there is no water flow signal (No at step 100)
In this case, operation stop (step 101) is selected and operation is not performed.

If there is a water flow signal (Yes at step 100), the timer 71 is activated at the same time as shown in FIG. 3 (step 102). The operating time of timer 71 is
After 0.5 seconds, the inlet water temperature is read based on the temperature signal from the inlet water temperature thermistor 35 (step 103), and the combustion amount is calculated (step 103).
104).

The incoming water temperature read at this time is the incoming water temperature detected after t seconds have elapsed since the water flow signal was received, so it is not the temperature of the water that had been stagnant in the water supply pipe 30, but the temperature of the new water. This is the temperature of the water entering the supply pipe 30. Therefore, by calculating the amount of combustion based on this incoming water temperature, the temperature of the water supplied after the start of combustion can be set to the set temperature.

If there is a water flow signal after calculating the combustion amount (Yes in step 105), the water heater is operated (step 106), and combustion air is supplied from the combustion fan 12 and fuel gas is supplied from the gas supply pipe 20. The fuel is supplied through each electromagnetic valve, and combustion starts according to a predetermined sequence.

Thereafter, the inlet water temperature is sequentially read (step 103), the combustion amount is calculated based on the inlet water temperature (step 104), and operation continues as long as there is a water flow signal.

If hot water supply is stopped during operation and the water flow signal is stopped (No in step 105), the operation is stopped (step 101).

As described above, in the present invention, since the inlet water temperature read in order to calculate the combustion amount in advance is read t seconds after the water flow signal is applied, the temperature of the water remaining in the water supply pipe 30 at the start of operation is The temperature of the newly heated water can be detected without detecting the temperature of the water. Therefore, the temperature of the water supplied will not be too high or too low relative to the set temperature, and the water heater can be used safely.

In this example, a gas combustion type water heater was explained, but water heaters using other fuels such as oil or water heaters using electric heaters can be similarly controlled to supply water at a set temperature. .

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the control device of this embodiment, Fig. 2 is a schematic configuration diagram showing the gas combustion water heater of this embodiment, and Fig. 3 is for explaining the operation of the microcomputer of this embodiment. FIG. 4 is a flowchart for explaining the operation of the microcomputer of this embodiment. In the figure, 11... burner (heating means), 35...
Inlet water temperature thermistor (inlet water temperature detection means), 66...
Water amount detection circuit (water flow detection means), 70... microcomputer (control means), 71... timer (time measurement means).

Claims (1)

[Scope of Claims] 1. Water flow detection means for detecting water entering the water heater and generating a water flow signal; flow rate detection means for detecting the amount of water entering the water heater; a heating means for heating water entering the water heater; a temperature setting means for setting the temperature of the water heated by the heating means; and a temperature setting means for detecting the temperature of the water entering the water heater. , an incoming water temperature detection means that generates a temperature signal according to the detected temperature; and a heating means based on the detected flow rate of the flow rate detection means, the set temperature of the temperature setting means, and the temperature signal detected by the water inflow detection means. A water heater comprising a control means for controlling the heating amount of the water heater, wherein the control means includes a timer that operates for a predetermined period of time after receiving a water flow signal from the water flow detection means, and when the timer ends its operation. The water heater is characterized in that reading of the temperature signal of the input water temperature detection means is subsequently started, and control of the heating means is started based on the read temperature signal.