JPH07103565A - Water heater - Google Patents

Abstract

(57) [Abstract] [Purpose] Achieves excellent rising characteristics and transient characteristics without the need for a water temperature detector. [Structure] Before the heat exchanger 3 is heated by the burner 8, the input signal of the tap water temperature detecting device 5 is set to the first incoming water temperature value,
When the heat exchanger 3 is heated by the burner 8 and the set temperature of the external input device 14 and the input signal of the hot water temperature detection device 5 become equal, the combustion amount of the burner 8, the input signal of the water amount detection device 2, and the hot water temperature detection device. From the input signal of 5, the second and subsequent water temperature values are calculated. This makes it possible to obtain the rising characteristics and transient characteristics of the hot water temperature, which are the same as those provided with the incoming water temperature detecting device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater which obtains hot water by utilizing the heat of combustion of gas or the like.

[0002]

2. Description of the Related Art A conventional water heater of this type has a structure as shown in FIG.

Water passes through a water inlet temperature detecting device 1 and a water amount detecting device 2 from a water inlet, absorbs heat in a heat exchanger 3, passes through a water amount adjusting device 4, a hot water outlet temperature detecting device 5, and is discharged from an outlet. It The gas passes from the gas inlet through the original solenoid valve 6 and the gas proportional valve 7, and is burned by the burner 8 by the combustion air fan 9.

The operation start of the water heater is input by the operation switch 15 of the external input device 14, the set temperature is input by the temperature switches 16, 17, 18 of the external input device 14, and the tap water temperature of the appliance is provided in the water passage. It is converted into an electric signal by the tapping temperature detection device 5 thus obtained, and the output signal thereof is inputted to the control device 23. Similarly, the incoming water temperature is converted into an electric signal by the incoming water temperature detecting device 1 provided in the water passage, and the incoming water amount is converted into an electric signal by the water amount detecting device 2 provided in the water passage, and the output signal thereof is controlled by the control device 23. Entered in.

The control device 23 controls the input signal of the external input device 14, the input signal of the incoming water temperature detecting device 1 and the water amount detecting device 2.
Of the control water amount of the water amount adjusting device 4 and the combustion amount of the burner 8 based on the input signal of the hot water outlet temperature detecting device 5 and the water amount / combustion amount determining means 24, and the water amount adjusting device 4 so that the determined water amount is achieved. Water amount control device control means 13 to be driven
And the original solenoid valve 6 of the gas so that the amount of combustion decided,
It is composed of a proportional valve 7 for gas and a combustion amount control means 12 for driving a fan 9 for combustion air.

FIG. 5 shows an example of a concrete circuit of a main part. The control device 23 comprises a microcomputer 25 and its peripheral devices. The microcomputer 25 shown here is a so-called one-chip microcomputer having a CPU, a ROM, a RAM, and an input / output unit.

The incoming water temperature detecting device 1, the water amount detecting device 2, and the outgoing hot water temperature detecting device 5 are an analog multiplexer 19, A
It is connected to the microcomputer 26 via the / D converter 20 and sends each input signal. In addition, the operation switch 15, the temperature switch 16 of the external input device 14,
An input signal is sent to the microcomputer 25 by 17, 18. On the other hand, an electrical signal is sent from the output section of the microcomputer 25 to the water amount adjusting device 4, the original solenoid valve 6, the gas proportional valve 7, and the combustion air fan 9 via the D / A converter 22.

Next, an example of a sequence diagram of this water heater is shown in FIG. The power of the water heater is turned "ON" in S1, the operation switch 15 of the external input device 14 is turned "ON" in S2,
The set temperature is input by the temperature switches 16, 17 and 18. When the faucet is opened in S3 and water flows through the water passage and the water amount detected by the water amount detecting device 2 becomes equal to or greater than the ignition water amount, the ignition sequence is started in S4.

In S14, the input signals of the water inlet temperature detecting device 1 and the water amount detecting device 2 are read, and in S7 the water inlet temperature detecting device 1,
The amount of water and the amount of combustion to be controlled are determined by the input signals of the set temperature of the amount of water detecting device 2 and the external input device 14, and the amount of water adjusting device 4 and the proportional valve 7 for gas are adjusted so that the amounts of water and the amount of combustion are determined in S8. , Drives the combustion air fan 9. S9
The input signal of the hot water temperature detecting device 5 is read by and the step S8 is repeated so that the input signal of the hot water temperature detecting device 5 and the input signal of the set temperature of the external input device 14 become the same at S10.

When the input signal of the hot water outlet temperature detecting device 5 and the input signal of the set temperature of the external input device 14 become the same in S10, if the water amount detected by the water amount detecting device 2 is not less than the extinguishing water amount in S12, S14 to S10 are executed. Repeatedly, if the amount of water for extinguishing water becomes less than or equal to the amount of fire extinguishing water, the process returns to S3. If the amount of ignition water is less than or equal to S3, S
If it is equal to or more than the amount of ignition water in S3, the process proceeds to S4.
In S13, the operation switch 15 of the external input device 14 is set to "O".
If "N", the process returns to S3, and if "OFF", the process returns to S2.

Thus, the amount of water and the amount of combustion to be controlled are determined by the input signals of the set temperature of the incoming water temperature detecting device 1, the water amount detecting device 2, and the external input device 14, and the amount of water is controlled by the input signal of the outlet hot water temperature detecting device 5. And the method of correcting the combustion amount is
It is called FF + FB (feedforward + feedback) control, and it controls the amount of water to be controlled quickly and excels in the rising characteristics and transient characteristics of the hot water temperature.

[0012]

However, in order to perform such FF + FB control, the inlet water temperature detecting device 1, the water amount detecting device 2, and the outlet hot water temperature detecting device 5 are required, and the cost is high. Met.

In order to solve the above-mentioned conventional problems, the present invention controls the input water temperature detecting device by the microcomputer in the same manner as when the input water temperature detecting device is provided, even if the input water temperature detecting device is eliminated. It is an object of the present invention to provide a water heater which is quickly controlled to an appropriate amount of water, has excellent rising characteristics and transient characteristics of hot water temperature, is low in cost, and is easy to use.

[0014]

In order to achieve the above object, the means of the water heater of the present invention uses the input signal of the hot water outlet temperature detecting device as the first inlet water temperature before the heat exchanger is heated by the burner. When the heat exchanger is heated by the burner and the set temperature of the external input device and the input signal of the hot water temperature detection device become equal, the burner combustion amount, the input signal of the water amount detection device, and the input signal of the hot water temperature detection device. The second and subsequent input water temperature values are calculated and stored, and control means for controlling the water amount control device by these input water temperature values, the input signal of the water amount detection device, the set temperature of the external input device and the input signal of the hot water temperature detection device are provided. Be prepared.

[0015]

According to the present invention, by the above means, the input signal of the tap water temperature detecting device is set to the first incoming water temperature value before the heat exchanger is heated by the burner, the heat exchanger is heated by the burner, and the external input device of the external input device is operated. When the set temperature and the input signal of the hot water temperature detection device become equal, the second and subsequent water input temperature values are calculated from the burner combustion amount, the water amount detection device input signal, and the hot water temperature detection device input signal, and these water input values are calculated. Control is performed according to the temperature value in the same way as when there is a water temperature detector.

[0016]

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

FIG. 1 shows an embodiment of the present invention. Water passes through the water amount detecting device 2 through the water inlet, absorbs heat in the heat exchanger 3, passes through the water amount adjusting device 4, the hot water outlet temperature detecting device 5, and is discharged through the outlet. From the gas inlet, the gas is the original solenoid valve 6,
The gas passes through a proportional valve 7 and is burned by a burner 8 by a combustion air fan 9.

The start of the operation of the water heater is input by the operation switch 15 of the external input device 14, the set temperature is input by the temperature switches 16, 17, 18 of the external input device 14, and the tap water temperature of the appliance is provided in the water passage. The hot water temperature detecting device 5 thus converted converts the electric signal into an electric signal, and the output signal is input to the control device 10. Similarly, the water input amount is converted into an electric signal by the water amount detection device 2 provided in the water passage, and the output signal thereof is input to the control device 10.

The control device 10 controls the input signal of the external input device 14, the input signal of the water amount detection device 2, and the hot water temperature detection device 5.
Control signal of the water amount adjusting device 4 and the burner 8 by the input signal of
Water amount / combustion amount determining means 11 for determining the combustion amount of water, a water amount adjusting device control means 13 for driving the water amount adjusting device 4 so as to obtain the determined water amount, and the source electromagnetic wave of the gas so as to obtain the determined combustion amount. It is composed of a valve 6, a proportional valve 7 for gas, and a combustion amount control means 12 for driving a fan 9 for combustion air.

FIG. 2 shows an example of a concrete circuit of the main part. The control device 10 includes a microcomputer 21 and its peripheral devices. The microcomputer 21 shown here is a so-called one-chip microcomputer having a CPU, a ROM, a RAM, and an input / output unit.

The water amount detecting device 2 and the discharged hot water temperature detecting device 5 are
It is connected to the microcomputer 21 via the analog multiplexer 19 and the A / D converter 20, and each input signal is sent. Further, an input signal is sent to the microcomputer 26 by the operation switch 15 and the temperature switches 16, 17, 18 of the external input device 14. On the other hand, from the output section of the microcomputer 26, the D / A converter 2
An electrical signal is sent via 2 to the water amount control device 4, the original solenoid valve 6, the gas proportional valve 7, and the combustion air fan 9.

Next, an example of a sequence diagram of this water heater is shown in FIG. The power of the water heater is turned "ON" in S1, the operation switch 15 of the external input device 14 is turned "ON" in S2,
The set temperature is input by the temperature switches 16, 17 and 18. When the faucet is opened in S3 and water flows through the water passage and the water amount detected by the water amount detecting device 2 becomes equal to or greater than the ignition water amount, the ignition sequence is started in S4.

In step S5, the input signal of the tap water temperature detecting device 5 is read before the heat exchanger 3 is heated by the burner 8 in order to determine the first incoming water temperature value. This input signal has almost the same value as the input signal of the water temperature detecting device shown in S14 of FIG. 6 of the conventional example, and is stored as the first water temperature value.

The input signal of the water amount detecting device 2 is read in S6, and the first incoming water temperature value and the water amount detecting device 2 in S5 are read in S7.
And the amount of water to be controlled and the amount of combustion to be controlled by the input signal of the set temperature of the external input device 14, and the amount of water control device 4, the gas proportional valve 7, so that the amount of water and the amount of combustion to be determined in S8.
The fan 9 for combustion air is driven. In S9, the input signal of the hot water outlet temperature detecting device 5 is read, and in S10, S8 is repeated so that the input signal of the hot water outlet temperature detecting device 5 and the input signal of the set temperature of the external input device 14 become the same.

In S10, when the input signal of the hot water temperature detecting device 5 and the input signal of the set temperature of the external input device 14 become the same, in S11, the combustion amount of the burner 8, the input signal of the water amount detecting device 2, and the hot water temperature detecting device. With the input signal of 5, the second and subsequent water temperature values are calculated. The combustion amount of the burner 8 is calculated by the output signal of the gas proportional valve 7, and the incoming water temperature can be calculated by the combustion amount, the water amount, and the hot water temperature. That is, since the combustion amount = (outlet water temperature−inlet water temperature) × water amount, the water inlet temperature to be obtained can be calculated by the following: inlet water temperature = outlet temperature−combustion amount / water amount. This calculated value is stored as the second incoming water temperature value.

If the amount of water detected by the water amount detecting device 2 is not less than the amount of fire extinguishing water in S12, S6 to S10 are repeated. At this time, in the determination of the incoming water temperature value in S5, 2 calculated in S11 is used.
Use the second incoming temperature value. If the amount of water for extinguishing water becomes less than or equal to S12, the process returns to S3. If the amount of ignition water is less than or equal to S3, S13
If the amount of ignition water is equal to or more than S3, the process goes to S4. S1
If the operation switch 15 of the external input device 14 at 3 is "ON", the process returns to S3, and if "OFF", the process returns to S2.

In any of these cases, when entering S5 next time, the entering water temperature value calculated in S11 is used to determine the entering water temperature value in S5. That is, the determination of the incoming water temperature value in S5 is made by the input signal of the hot water outlet temperature detecting device 5 when the power of the water heater is turned "ON"
The second and subsequent ones are determined by the calculation of S11.

According to such a sequence, since the incoming water temperature value is updated every day, the accurate incoming water temperature can be known regardless of the season without the incoming water temperature detecting device. In the same manner as the above, the hot water heater can be controlled quickly by controlling the amount of water to be controlled, has excellent rising characteristics and transient characteristics of the hot water temperature, is low in cost, and is easy to use.

[0029]

As described above, in the water heater of the present invention, before the heat exchanger is heated by the burner, the input signal of the tap water temperature detecting device is set to the first incoming water temperature value, and the heat exchanger is set by the burner. When the set temperature of the external input device and the input signal of the hot water temperature detection device become equal due to heating, the second and subsequent input water temperature values are calculated from the burner combustion amount, the water amount detection device input signal and the hot water temperature detection device input signal. Just like when there is a water temperature detector, the water temperature should be controlled quickly to control the amount of water to be controlled, and the rising and transition characteristics of the hot water temperature are excellent, and the cost is low and the usability is good. Is to have.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a water heater according to an embodiment of the present invention.

[Fig. 2] Circuit diagram of the water heater

FIG. 3 is a sequence diagram of the water heater.

FIG. 4 is a configuration diagram of a conventional water heater.

[Fig. 5] Circuit diagram of the water heater

FIG. 6 is a sequence diagram of the water heater.

[Explanation of symbols]

 2 Water amount detecting device 3 Heat exchanger 4 Water amount adjusting device 5 Hot water temperature detecting device 8 Burner 11 Water amount / combustion amount determining means

Claims (1)

[Claims] 1. A water amount detecting device for detecting a flow rate of water flowing into a heat exchanger, a tap water temperature detecting device provided downstream of the heat exchanger, a water amount adjusting device for adjusting water amount, and the heat exchanger. Before the heat exchanger is heated by the burner, an external input device for inputting a set temperature, and an input signal of the hot water outlet temperature detection device as the first incoming water temperature value, and When the heat exchanger is heated and the set temperature of the external input device and the input signal of the hot water temperature detection device become equal, the combustion amount of the burner, the input signal of the water amount detection device, and the input signal of the hot water temperature detection device. The second and subsequent incoming water temperature values are calculated and stored, and the water amount adjusting device is operated by these incoming water temperature values, the input signal of the water amount detecting device, the set temperature of the external input device, and the input signal of the hot water temperature detecting device. Water heater provided with a control means for controlling.