JPH01203844A - Hot-water apparatus - Google Patents

Abstract

PURPOSE:To always maintain a set temperature of hot water delivery and shorten the time interval during which the set temperature is attained by computing the opening of a water flow regulating valve based on the temperature differential between the set temperature and measured feed water temperature, and controlling the opening of said water flow regulating valve based on the second control signal to the water flow regulating valve which is computed based on the previously computed opening. CONSTITUTION:When the water heater is operated, a second computing means 4 computes the opening of a water flow regulating valve based on the characteristics stored in a memory means 3 from the temperature differential between the set temperature set with a hot water temperature setting device 35 and the feed water temperature measured by a temperature sensor 28, and, based on this, a second control means 5 computes the second control signal so as to set the opening of the water flow regulating valve at the computed opening. A first computing means 1 compares the temperature of hot water delivery measured by a temperature sensor 29 with the set temperature to compute the first control signal, and a first control means 2 controls a gas flow control valve 21 to bring the temperature of hot water delivery to the set temperature. Since the water flow regulating valve 26 is throttled, the feed water amount will not exceed the maximum capacity of the water heater even if the hot water tap is fully opened. Therefore, hot water can be delivered at a temperature which is set high, and the time interval to reach the set temperature can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an instantaneous water heater type water heater using gas.

(Prior art) This type of hot water supply device includes, for example, Japanese Unexamined Patent Publication No. 61-99022.
As disclosed in the above publication, there is a system in which the opening degree of a gas valve that controls the amount of gas supplied to a gas burner is continuously changed so that hot water at a set temperature can be obtained regardless of an increase or decrease in the amount of hot water. .

In this type of water heater, as shown in Fig. 3, the maximum capacity characteristic (maximum gas valve opening) A and the minimum capacity characteristic (minimum gas valve opening) B in the relation diagram between hot water output amount and hot water temperature are For example, when the hot water temperature is set to the maximum temperature T1, the opening degree of the gas valve changes according to the hot water flow rate when the hot water flow rate is within 11, and hot water at the temperature T1 is obtained.
If the hot water output is 71 or more, the amount of heating by the gas burner will not increase even if the hot water output increases, so if the hot water output becomes ■2, the hot water temperature will drop to T2, and the hot water tap will be fully opened and the hot water output will be v3. If so, the hot water temperature will drop to T3. It is undesirable for the hot water temperature to drop significantly below the set temperature, so conventionally a restrictor was installed in the water supply pipe to the heat exchanger to prevent the hot water flow from exceeding v2 even when the hot water tap was fully opened. This prevents the hot water temperature from dropping below temperature T2, which is slightly lower than the set temperature T1, even if the hot water tap is fully opened when the hot water temperature is set at the maximum temperature T1.

(Problem to be Solved by the Invention) However, in such conventional technology, even when the hot water temperature is set to a low temperature T3, the amount of hot water that comes out is limited to v2 or less, and the amount of hot water that comes out corresponds to the maximum heating capacity of the water heater. ■
It doesn't reach 3.

Therefore, when relatively low-temperature hot water is used, such as in a shower, there is a problem that only a small amount of hot water can be obtained even though the heating capacity is sufficient, which is inconvenient.

To solve this problem, a water flow control valve operated by an electronic control device is installed in the water supply pipe, and this water flow control valve is normally kept fully open, so that even when the gas valve is at its maximum opening, the hot water temperature remains at the set temperature. There is a technique that reduces the opening of the water flow control valve to reduce the flow rate and raise the hot water temperature to the set temperature if the water flow rate does not reach the set temperature. However, in this technology, the amount of hot water is controlled by the water flow control valve after the opening degree of the gas valve reaches its maximum, so if the hot water temperature is set around the maximum temperature T1, There is a problem in that there is a large time delay until T1 is reached.

The present invention attempts to solve each of these problems.

(Means for Solving the Problems) For this purpose, the water heater according to the present invention includes a heat exchanger 15 and water supply pipes 16 connected before and after the heat exchanger 15, as shown in FIG.
and a hot water supply pipe 17, a hot water temperature sensor 29 provided in the hot water supply pipe, a gas burner 11 that heats the water supplied through the heat exchanger 15, and a gas burner 11 whose opening degree changes continuously. The gas amount is determined by comparing the outlet temperature detected by the gas amount control valve 21 that controls the supply amount, the hot water temperature setting device 35, and the hot water temperature sensor 29 with the set temperature set by the hot water temperature setting device 35. a first calculation means 1 for calculating a first control signal having a value that increases the opening degree of the control valve 21 when the outlet temperature is lower and decreases the opening degree when the outlet temperature is higher; and the first control signal. In the hot water supply apparatus, the first control means 2 is provided in the water supply pipe 16 to control the opening degree of the gas amount control valve 21 based on the following: The water flow regulation valve 26 that regulates the water supply volume, the water temperature sensor 28 provided in the water supply pipe 16, and the heat exchange with respect to the opening degree of the water volume regulation valve 26 when the gas volume control valve 21 is set to the maximum opening degree. The water flow regulating valve 26 is stored in the storage means 3 which stores the temperature rise characteristics caused by the water temperature sensor 15 and the characteristics stored in the storage means 3 based on the temperature difference between the set temperature and the water supply temperature detected by the water temperature sensor 28. second calculation means 4 for calculating the opening degree of
and a second control means 5 which calculates a second control signal having a value such that this opening degree is applied to the water volume regulation valve 26 and controls the opening degree of the water volume regulation valve based on the second control signal. It is something.

(Function) When the hot water supply device starts operating due to the start of hot water dispensing, the second calculating means 4 stores the temperature difference based on the temperature difference between the set temperature set by the hot water temperature setting device 35 and the water supply temperature detected by the water temperature sensor 28. Water flow regulating valve 2 based on the characteristics stored in means 3
6, and the second control means 5 calculates the second opening degree based on this.
The control signal is calculated to set the water flow regulating valve 26 to the opening degree calculated by the second calculation means 5. If the temperature difference is large, the set opening of the water flow regulating valve 26 becomes small and the heat exchanger 4
If the temperature difference is small, the set opening degree is increased and the maximum water supply amount is regulated to be large. Simultaneously with the operation of the water flow regulating valve 26, the first calculation means 1 compares the outlet temperature detected by the hot water temperature sensor 29 with the set temperature to calculate a first control signal, and the first control means 1 calculates a first control signal. controls the gas amount control valve 21 based on this first control signal, and increases the opening degree of the gas amount control valve 21 when the tapping temperature is lower than the set temperature;
When the hot water outlet temperature is high, it is decreased and the hot water outlet temperature is set as the set temperature. Since the water flow regulating valve 26 is throttled so that the maximum amount of water supplied is reduced when the set temperature is high, the amount of water supplied to the heat exchanger 15 will not exceed the maximum capacity of the water heater even if the hot water tap is fully opened. Therefore, hot water at a predetermined high set temperature can be obtained. Furthermore, when the set temperature is low, the water flow regulating valve 26 is opened so that the maximum water supply amount increases, so that when the hot water tap is opened, a large amount of hot water can be obtained within the maximum capacity range. The setting of the maximum amount of water supplied to the heat exchanger 15 by the water amount regulating valve 26 is carried out immediately after the start of operation of the water heater, and in parallel with the outlet temperature control by the gas amount control valve 21, so that the outlet water temperature is set to the maximum temperature. Even if it is set close to the temperature, the time from the start of hot water tap until the hot water temperature reaches the set temperature will be shortened.

(Effects of the Invention) As described above, according to the present invention, it is possible to always obtain hot water at the set temperature regardless of the level of the set temperature or the amount of hot water dispensed, and when the temperature is low, the amount of hot water dispensed is increased to supply hot water. The maximum capacity of the equipment can always be demonstrated. Further, the time from the start of hot water tap until the hot water tap temperature reaches the set temperature can be shortened, and as a result, a water heater that is easy to use can be obtained.

(Example) The present invention will be explained below using examples shown in FIGS. 2 to 5.

As shown in FIG. 2, a gas burner 11 is installed in the lower part of the inner shell 10 of the instantaneous water heater, and a safety valve 2 that only opens and closes is installed.
Gas is supplied by a gas supply path 12 provided with a gas amount control valve 21 whose opening degree changes continuously from zero, and combustion air is supplied by an electric fan 13 provided on the lower side of the inner shell 10. . A water supply pipe 1 connected to the inlet side of a fin-tube heat exchanger 15 provided above the gas burner 11
6 is provided with a water flow sensor 25, a water temperature sensor 28, a water flow regulating valve 26 whose opening degree changes continuously, and a water governor 27, and a hot water supply pipe 17 connected to the outlet side is provided with a water temperature sensor 29 and a hot water tap. 18 are provided. The water supplied from the water supply pipe 16 is heated by the gas burner 11 when passing through the heat exchanger 15, reaches a predetermined temperature, and is discharged from the hot water tap 18. The water governor 27 operates when the water supply pressure to the water supply pipe 16 fluctuates rapidly due to rapid opening and closing of faucets of peripheral equipment, etc., to smooth out the amount of water supplied. Further, the electric fan 13 is connected to an electronic control device 30 described below.
The amount of air blown is controlled in two stages depending on the amount of gas supplied.

An electronic control device 30 that controls the water heater includes a microprocessor (hereinafter simply referred to as CPU) 31 and a storage device 32.
are the main components, and the CPU 31 is connected to a safety valve 20 and a gas amount control valve 21 via interfaces 33 and 34.
, electric fan 13, hot water temperature sensor 29, water flow sensor 25,
Water temperature sensor 28, water flow regulation valve 26, and hot water temperature setting device 35
is connected. In this embodiment, the safety valve 20 is an open/close solenoid valve operated by a solenoid 20a, the gas flow control valve 21 is a solenoid valve whose opening degree changes continuously depending on the current applied to the solenoid 21a, and the water flow control valve 26
is an electric valve whose opening degree is continuously changed by a servo motor 26a. The hot water setting device 35 is used to set the hot water temperature to a value desired by the user. Storage device 3
The ROM 2 contains heat exchange information for the opening degree of the water flow regulating valve 26 when the water heater is at its maximum capacity, that is, the gas flow regulating valve 21° is at its maximum opening, and the hot water tap 18 is fully open.
515 is stored.

This characteristic is such that the temperature rise by the heat exchanger 15 decreases as the opening degree of the water flow regulating valve 26 increases, as shown in FIG. 4C. Note that instead of having this characteristic as a continuous curve like C in FIG. 4, it may have a step shape like C1.

Next, the operation of the above embodiment will be explained with reference to the flowchart shown in FIG.

When the electronic control unit 30 is powered on, the control program according to the flowchart of FIG. 5 starts operating. Hot water tap 1
8 is closed, the water flow sensor 25 is not activated and the control operation is in a standby state in which the control operation does not proceed beyond step 100. However, if the hot water tap 18 is opened and the flow rate exceeds a predetermined minimum flow rate, the water flow sensor 25 is activated. If so, proceed to step 101 and
U31 operates the electric fan 13 to perform prepurge for a predetermined period of time. Next, in step 102, the on-off solenoid valve 20 is opened, and at the same time the gas amount control valve 21 is set to a predetermined small opening required for ignition, and the ignition device in the enclosure is activated to ignite the gas ejected from the gas burner 11. With the above steps, the water heater starts.

Following the startup, the CPU 31 executes steps 11O to 11.
2, the water supply temperature H detected by the water temperature sensor 28
1 Set temperature I set by the user using the hot water temperature setting device 35
I 2 and the hot water temperature H detected by the hot water temperature sensor 29
3 is read, and in step 113, the temperature difference HO (=H2-H1) between the set temperature H2 and the water supply temperature H1 is calculated. Next, in step 114, the CPU 31 determines that the temperature rise by the heat exchanger 15 when the gas amount control valve 21 is set to the maximum opening, that is, the heating capacity of the water heater is at its maximum, and the hot water tap 18 is fully opened, is equal to this temperature difference HO. The opening degree of the water flow regulating valve 26 is calculated based on the characteristic C stored in the ROM of the storage device 32, and a predetermined number of pulse signals corresponding to this are calculated in step 115 and distributed to the servo motor 26a. and sets the opening of the water flow regulating valve 26 to the calculated opening.As a result, when the temperature difference HO becomes large, the water flow regulating valve 26 is set to a small opening, and when the temperature difference HO becomes small, the water flow regulating valve 26 is set to a small opening. The water flow regulating valve 26 is maintained at a wide opening.As a result, when the hot water outlet temperature is set to the maximum temperature T1 in FIG. The water supply amount, that is, the maximum hot water output amount, is regulated by Vl, and when the hot water temperature is set to medium temperature T2 and low temperature T3, the maximum hot water output amount is regulated to ■2 and ■3, respectively.The absolute maximum hot water output amount is This is given by the maximum hot water output fiV3 when the water flow regulating valve 26 and the hot water tap 18 are fully opened, and this maximum hot water flow v3 is determined in consideration of corrosion of various parts due to water flow.

Continuing (In steps 116 to 119, the CPU 31 compares the hot water outlet temperature H3 with the set temperature H2, and if H3<H2, increases the current value I applied to the gas amount control valve 21 by a predetermined amount Δ■, H3>H2 If so, it is decreased by a predetermined amount ΔI, the control current of value 1 changed in step 120 is output to the solenoid 21a, and the opening degree of the gas amount control valve 21 is changed to bring the outlet hot water temperature H3 closer to the set temperature H2. As long as the hot water tap 18 is open, the control operation returns from step 121 to step 110 at predetermined intervals, and the CPU 3
1 repeats the operations of steps 110 to 120, thereby making the hot water tap temperature T3 the set temperature H2 set by the hot water temperature setting device 35, and hot water is tapped. When the hot water tap 18 is closed, the control operation proceeds from step 121 to step 122, and the CPU 3
t closes the safety valve 20, stops combustion of the gas burner 11, and returns to the standby state mentioned at the beginning of the explanation of this operation.

According to the embodiment described above, when the hot water temperature is set to the maximum temperature Tl, the amount of hot water that comes out is maximized as the opening degree of the hot water tap 18 is increased, but the amount of hot water that comes out does not exceed V1. , the tapping temperature is maintained at the maximum temperature T1. When the hot water temperature is set to medium temperature T2 and low temperature T3, the maximum amount of hot water will increase within the capacity of the hot water supply device as the hot water temperature decreases, and will become ■2 and V3, respectively, so the hot water temperature will be Set temperature T2. The temperature is maintained at T3, and the maximum amount of hot water can be increased as the set temperature decreases. Furthermore, the setting of the maximum amount of hot water supplied by the water amount regulation valve 26 is performed almost simultaneously with the hot water temperature control by the gas amount control valve 21 according to the characteristic C stored in the storage device 32 in advance.
Compared to conventional technology, which regulates the maximum amount of hot water supplied by a water flow regulating valve after the hot water temperature stabilizes to recover from the drop in hot water temperature that would occur if the maximum capacity is exceeded, the hot water temperature reaches the set temperature immediately after hot water starts being tapped. In particular, if the water flow regulating valve is thick (the operating hot water temperature is set near the maximum temperature), the time can be significantly shortened compared to the conventional method.

The above operation has been explained assuming that the water supply temperature H1 is a specific temperature, but as the water supply temperature H1 rises, the maximum capacity characteristic and minimum capacity characteristic of the water heater will change to A'' and Bo in Fig. 3.
As shown in Figure 2, the water supply temperature H1 moves in parallel upward by the increase in the water supply temperature H1, and the operation is performed in the range between the two characteristics A' and B''. The absolute maximum amount of hot water ■3 remains unchanged.

Similarly, when the water supply temperature H1 decreases, the maximum and minimum capacity characteristics shift downward in parallel, and each hot water tap.

The maximum amount of hot water at different temperatures will decrease somewhat. Water supply temperature H1
In order to obtain hot water at the maximum temperature T1 even when the temperature decreases to the expected minimum value, the characteristic C in FIG.

When the rising temperature characteristic of the heat exchanger 15 is made step-like as shown in C1 of FIG. 4, the water heater has the characteristic A of FIG. 3.
It operates in the range between 1 and B. In this example,
Although the step-like characteristic C1 is assumed to be in contact with the lower side of the characteristic C, it may be in a step-like shape spanning both sides of the characteristic C, or may be in contact with the upper side of the characteristic C. In this case, if the amount of hot water dispensed is maximized at the set temperature, the tapped water temperature will be slightly lower than the set temperature.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a water heater according to the present invention, Fig. 2 is a structural diagram of an embodiment, Fig. 3 is a characteristic diagram of the amount of hot water discharged and the temperature of hot water discharged, and Fig. 4 is a characteristic diagram stored in the storage device. FIG. 5 is a flowchart of the operation. Explanation of symbols 1...first calculation means, 2...first control means, 3...
- Storage means, 4... Second calculation means, 5... Second control means, 11... Gas burner, 15... Heat exchanger, 1
6... Water supply pipe, 17... Hot water supply pipe, 21... Gas amount control valve, 26... Water amount regulation valve, 28... Water temperature sensor, 29... Hot water temperature sensor, 35... Water temperature setting device.

Claims (1)

[Claims] A heat exchanger, a water supply pipe and a hot water supply pipe connected before and after the heat exchanger, a hot water temperature sensor provided in the hot water supply pipe, and a gas burner that heats the water supply passing through the heat exchanger, the opening degree of which is continuously adjusted. A gas amount control valve that changes to control the amount of gas supplied to the gas burner, a hot water temperature setting device, and a hot water temperature detected by the hot water temperature sensor and a set temperature set by the hot water temperature setting device. a first calculation means for calculating a first control signal having a value such that the opening degree of the gas amount control valve is increased when the hot water outlet temperature is lower and is decreased when the hot water outlet temperature is higher; In the hot water supply apparatus, the water supply apparatus includes a first control means for controlling the opening degree of the gas amount control valve based on a control signal, which is provided in the water supply pipe and whose opening degree continuously changes to control the amount of water supplied to the heat exchanger. a water flow regulating valve that regulates the water flow, a water temperature sensor provided in the water supply pipe, and a temperature rise characteristic caused by the heat exchanger relative to the opening of the water flow regulating valve when the gas flow control valve is set to a maximum opening. a storage means for calculating the opening degree of the water flow regulating valve from the characteristic stored in the storage means based on the temperature difference between the set temperature and the water supply temperature detected by the water temperature sensor;
A hot water supply apparatus comprising a second control means for calculating a second control signal having a value such that the opening degree is applied to the water flow regulating valve and controlling the opening degree of the water flow regulating valve based on the second control signal.