JP2000161780A - Hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-water supplier, capable of preventing the excessive increase of amount of correcting heat when the supplying pressure of fuel, supplied to a burner, is reduced. SOLUTION: A hot-water supplying device is provided with a required heat amount operating means 41, operating the required heat amount F1 of the combustion of a burner from the objective temperature Ts of hot-water supply, a feed water temperature Tc and a feed water amount Q, and a corrected heat amount operating means 42, operating a corrected heat amount F, obtained by correcting the required heat amount F1 at least through integral correction so as to equalize a hot-water supplying temperature Th to the objective hot-water supplying temperature Ts. In such a hot-water supplying device, a supplying pressure deterioration detecting means 43, estimating the deterioration of the supplying pressure of fuel supplied to the burner, is provided to lower the maximum limit value of the corrected heat amount F when the supplying pressure deterioration detecting means 43 has detected the deterioration of supplying pressure of fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a required heat amount calculating means for calculating a required heat amount from a target hot water temperature, a water supply temperature and a water supply amount, and a correction for correcting the required heat amount so that the hot water temperature becomes equal to the target hot water temperature. The present invention relates to a hot water supply device including a correction calorific value calculating means for calculating a calorific value.

[0002]

2. Description of the Related Art Conventionally, in this type of hot water supply apparatus, a required heat quantity F1 is calculated from a target hot water temperature Ts, a hot water temperature Tc and a hot water quantity Q, and further, the hot water temperature Th is made equal to the target hot water temperature Ts. Target hot water supply temperature Ts and hot water supply temperature T
h, a correction calorie F is calculated based on the deviation of h, the opening of the proportional control valve is adjusted based on the calorie F, and the fuel supply amount supplied to the burner is determined. The number of revolutions of the fan supplying air was also determined. FIG.
FIG. 4 is a diagram showing the relationship between the corrected heat quantity F, the opening degree of the proportional valve, and the fan rotation speed. As the correction heat quantity F increases, the fan rotation speed and the opening degree of the proportional valve increase accordingly.

[0003]

However, in the conventional hot water supply apparatus, when the supply pressure of the fuel supplied to the burner decreases, the hot water supply temperature Th cannot reach the target hot water supply temperature Ts. FIG. 7 is a diagram showing the relationship between the gas proportional valve opening and the fuel supply amount. The line shows the relationship when the fuel supply pressure is not reduced, and the line shows the relationship when the fuel supply pressure is reduced. Is shown. In the line, as the proportional valve opening increases based on the corrected heat amount F, the fuel supply increases accordingly. However, in the line, even if the proportional valve opening is adjusted, the supply pressure of the fuel supplied to the burner decreases. Fuel supply does not increase. As a result, the hot water supply temperature Th cannot reach the target hot water supply temperature Ts, and the correction heat amount F is calculated based on the deviation between the target hot water supply temperature Ts and the hot water supply temperature Th. However, the correction heat amount F excessively increases due to the integral correction. At this time, the correction calorie F
The number of rotations of the fan increases with the increase in the fuel supply amount. On the other hand, there is a problem in that the fuel supply amount does not increase, so that the air amount becomes excessive and the burner flame lifts. Further, when the required heat amount F1 is reduced to a point where the target hot water supply temperature Ts is changed to a low value or the supply water amount Q is reduced so as not to be affected by the decrease in the fuel supply pressure, the correction heat amount F excessively increases. Therefore, there is a problem that the hot water supply temperature Th overshoots. The present invention has been made to solve the above problems, and a first object of the present invention is to prevent the correction calorific value from excessively increasing when the supply pressure of the fuel supplied to the burner decreases. An object of the present invention is to provide a hot water supply device that can perform the hot water supply. Further, a second object is to provide a water heater capable of detecting a decrease in the supply pressure of the fuel supplied to the burner using an existing sensor without providing a dedicated sensor.

[0004]

In order to achieve the above object, a first aspect of the present invention is to provide a fan for supplying air for combustion to a burner and an adjustment of a fuel supply amount supplied to the burner. A proportional control valve, a heat exchanger for heating water supplied from the water supply pipe and supplying it to the hot water supply pipe, a water quantity sensor for detecting a water supply water quantity Q passing through the water supply pipe, A hot water temperature sensor for detecting hot water temperature Tc, a hot water temperature sensor for detecting hot water temperature Th of hot water passing through the hot water pipe, a target hot water temperature Ts and a hot water temperature Tc.
Required calorie computing means for computing the required calorie F from the water supply water quantity Q, and a corrected calorie calculation for computing a corrected calorie F at least by correcting the required calorie F1 by integral correction so that the hot water temperature Th becomes equal to the target hot water temperature Ts. In the hot water supply device provided with the means, a supply pressure decrease detecting means for estimating a decrease in the supply pressure of the fuel supplied to the burner is provided, and when the supply pressure decrease detecting means detects a decrease in the fuel supply pressure, the correction heat amount F To lower the maximum limit. Therefore,
It works as follows. When the fuel supply pressure decreases and the fuel supply amount supplied to the burner decreases, the hot water supply temperature Th cannot reach the target hot water supply temperature Ts, and the correction heat amount F increases due to the integral correction. However, since the supply pressure drop detecting means detects a decrease in the supply pressure of the fuel and lowers the maximum limit value of the correction heat quantity F, the correction heat quantity F
Immediately reaches the maximum limit value, and thereafter, the calculation of the corrected heat amount F is stopped. Therefore, it is possible to prevent the corrected heat amount F from excessively increasing.

According to a second aspect of the present invention, in the hot water supply apparatus according to the first aspect, the supply pressure drop detecting means detects the supply water temperature Tc, the supply water temperature Th, and the supply water amount Q when the correction heat amount F is increasing.
It is determined that the fuel supply pressure has decreased when the actual output Fr calculated from the above does not increase. Therefore, the following operation is performed. When the correction heat amount F is increasing so that the hot water temperature Th reaches the target hot water temperature Ts, the actual output Fr is calculated from the hot water temperature Tc, the hot water temperature Th, and the hot water amount Q. Originally, when the correction heat amount F increases, the actual output Fr also increases because the supply amount of fuel supplied to the burner increases. Therefore, the amount of change in the actual output Fr is compared, and if the actual output Fr has not increased, it is determined that the fuel supply pressure has decreased. As described above, it is possible to detect a decrease in the fuel supply pressure based on the detection information of the existing sensor without adding a new sensor for detecting a decrease in the fuel supply pressure.

According to a third aspect of the present invention, in the hot water supply apparatus according to the first aspect, the supply pressure drop detecting means is provided when the correction coefficient calculated from the ratio of the required heat amount F1 to the corrected heat amount F is increased to a predetermined value or more. It is determined that the fuel supply pressure has decreased. Therefore, the following operation is performed. When the correction heat amount F is calculated so that the hot water supply temperature Th reaches the target hot water supply temperature Ts, the ratio between the required heat amount F1 and the correction heat amount F, that is,
The correction coefficient ratio F / F1 is calculated. When the fuel supply pressure decreases, the correction heat amount F increases so that the hot water supply temperature Th reaches the target hot water supply temperature Ts. Therefore, the correction coefficient ratio F / F1 also increases. Therefore, the correction coefficient ratio F / F1 is compared with a predetermined value, and if the correction coefficient ratio F / F1 has increased to a predetermined value or more, it is determined that the fuel supply pressure has decreased. As described above, it is possible to detect a decrease in the fuel supply pressure based on the detection information of the existing sensor without adding a new sensor for detecting a decrease in the fuel supply pressure.

According to a fourth aspect, in the hot water supply apparatus according to the first aspect, when an overshoot of the hot water supply temperature Th is detected, it is determined that the fuel supply pressure has decreased.
Therefore, the following operation is performed. When the correction heat amount F is calculated so that the hot water supply temperature Th reaches the target hot water supply temperature Ts, if the fuel supply pressure decreases, the correction heat amount F increases so that the hot water supply temperature Th reaches the target hot water supply temperature Ts. At this time, the required heat quantity F1
Drops to a value that does not suffer from a drop in fuel supply pressure,
Since the correction heat amount F has increased due to the decrease in the fuel supply pressure, the hot water supply temperature Th will overshoot. Accordingly, the overshoot detecting means detects the overshoot of the hot water supply temperature Th, thereby determining that the fuel supply pressure has decreased. As described above, it is possible to detect a decrease in the fuel supply pressure based on the detection information of the existing sensor without adding a new sensor for detecting a decrease in the fuel supply pressure.

According to a fifth aspect, in the hot water supply apparatus according to the first aspect, the maximum limit value of the corrected heat amount F is determined based on the actual output Fr calculated when the corrected heat amount F is at the maximum value. And Therefore, the following operation is performed. When the correction heat amount F is increasing so that the hot water temperature Th reaches the target hot water temperature Ts, the actual output Fr is calculated from the hot water temperature Tc, the hot water temperature Th, and the hot water amount Q. Originally, when the correction heat amount F increases, the actual output Fr also increases because the supply amount of the fuel supplied to the burner increases, so that the correction heat amount F and the actual output Fr become substantially equal. However, when the supply pressure of the fuel decreases, the actual output Fr does not increase. Therefore, the maximum limit value of the correction heat amount F is set to the actual output Fr when the correction heat amount F is at the maximum value, so that the correction heat amount The maximum limit value of F matches the actual output Fr at that time,
Thereafter, to stop the calculation of the corrected heat amount F, the corrected heat amount F
Can be prevented from increasing excessively.

According to a sixth aspect of the present invention, in the hot water supply apparatus according to the first aspect, a maximum limit value correcting means for resetting a maximum limit value of the correction heat amount F is provided. Therefore, when the supply pressure of the fuel returns, the maximum limit value of the corrected heat amount F is reset. Therefore, the maximum limit value of the corrected heat quantity F, which was limited to a low value when the decrease in the fuel supply pressure was detected, returns to the original large value, and the hot water supply capacity can be sufficiently exhibited.

According to a seventh aspect of the present invention, in the hot water supply apparatus according to the sixth aspect, the maximum limit value correcting means resets the maximum limit value of the corrected heat quantity F when the operation of the water heater is stopped. Therefore, each time the hot water is used, the maximum limit value of the correction heat amount F is reset, and each time the decrease in the fuel supply pressure can be detected, the hot water supply capacity can be sufficiently exhibited according to the fuel supply state at that time.

According to an eighth aspect of the present invention, in the hot water supply apparatus according to the sixth aspect, the maximum limit value correcting means resets the maximum limit value of the corrected heat amount F when the required heat amount F or the corrected heat amount F falls below a predetermined value. I decided that. Therefore, when the required heat quantity F1 decreases to a value at which the fuel supply pressure does not decrease due to a decrease in the feedwater quantity Q or the like, the maximum limit value of the correction heat quantity F is reset, and thereafter, the fuel supply pressure decreases again. Since it can be detected, the hot water supply capacity can be sufficiently exhibited according to the fuel supply state at that time.

According to a ninth aspect of the present invention, in the hot water supply apparatus according to the first aspect, when a decrease in the fuel supply pressure is detected, a subtraction process including a reset is performed on the calculated value of the corrected calorific value. Therefore, when detecting a decrease in the fuel supply pressure,
Since the calculated value of the correction heat amount F which is excessively large is subtracted or reset, the hot water supply temperature Th does not overshoot in the subsequent hot water supply.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram in which a water heater according to one embodiment of the present invention is applied to a gas water heater.
As shown in the figure, the gas water heater includes a water heater main body 1, a water supply pipe 3 for supplying water from the water supply source to the water heater main body 1, and a heat exchanger 7 for supplying water heated in the water heater main body 1. And a hot water supply pipe 5 for supplying the hot water to the hot water tap 11 through the hot water supply tap 11. The water supply pipe 3 is provided with a water supply temperature sensor 25 for detecting a temperature Tc of water from a water supply source and a water amount sensor 27 for detecting a water supply amount Q. Hot water supply temperature sensor 29 for detecting Th,
A water amount proportional valve 30 for limiting the amount of hot water is provided. Further, a fan 9 for supplying air necessary for combustion is provided in the water heater main body 1. Further, an igniter 15 necessary for igniting and a frame rod 17 for detecting the presence or absence of a flame are provided above the burner 13. Further, a gas supply pipe 23 for supplying gas to the burner 13 is provided.
The gas supply pipe 23 is provided with a gas proportional valve 19 for varying the amount of gas supplied and a gas solenoid valve 21 for starting / stopping gas supply.
The remote control 33 includes an operation switch 35 and a hot water tap 1.
A temperature setting switch 39 for setting a set temperature Ts of the hot water supplied from 1; a display unit 37 for displaying the set temperature Ts and the like.
Is provided. The gas water heater further includes the sensors 25,
The required heat amount F1 and the corrected heat amount F are calculated based on the detection signals (Tc, Q, Th, Ts) from the temperature setting switches 27, 29, and the gas proportional valve 19, the gas solenoid valve 21, and the fan. 9. A control unit 31 for controlling the water proportional valve 30 and the like is provided.

FIG. 2 is a control block diagram of the control unit 31 in one embodiment of the present invention. The required calorie computing unit (required calorie computing means) 41 includes:
The required heat amount F1 is calculated from the supplied water amount Q by the equation (1). F1 = Q × (Ts−Tc) Equation (1) (F1: kcal / min, Q: liter / min, Ts: ° C., Tc:
℃)

Further, a correction calorie calculating section (correction calorie calculating means) 42 calculates a correction calorie F by the equation (2) in order to make the hot water supply temperature Th coincide with the set temperature Ts. F = F1 × α = F1 × fPID (Ts−Th) / (Ts−Tc) Equation (2) (F: kcal / min, Th: ° C.) where fPID (Ts−Th) / (Ts−Tc) ) Is a correction coefficient α, which is obtained by performing a feedback calculation of proportional correction, integral correction, and differential correction based on the deviation between the set temperature Ts and the hot water supply temperature Th. The correction heat amount limiting unit 44 limits the correction heat amount F by a preset maximum capacity of the water heater. Therefore, the corrected heat amount limiting unit 44 functions as a maximum limit value correction unit for the corrected heat amount F of the water heater. In the present embodiment, the maximum capacity of the water heater is set to No. 24, and the corrected heat quantity F is limited by No. 24. When the correction heat amount F is limited by the maximum limit value 24, the integral correction calculation on the side where the correction coefficient increases is stopped. The gas solenoid valve control unit 4
5. The gas proportional valve controller 46, the fan controller 47, and the water proportional valve controller 48 drive the gas solenoid valve 21, the gas proportional valve 19, the fan controller 9, and the water proportional valve 30, respectively. Further, the supply pressure drop detecting means 43 supplies the fuel supply pressure drop information to the correction heat quantity calculation section 42 and the correction heat quantity restriction section 4.
Sent to 4. Upon receiving the supply pressure drop information, the correction heat quantity calculation unit 42 resets or subtracts the correction heat quantity that has increased due to the decrease in the supply pressure. That is, the correction coefficient α is reduced to 1 or a value smaller than the correction coefficient α immediately before receiving the supply pressure drop information. Therefore, in the subsequent hot water supply, the hot water supply temperature Th does not overshoot. Upon receiving the supply pressure drop information, the corrected heat amount restriction unit 44 lowers the maximum limit value of the corrected heat amount F. That is, the maximum limit value of No. 24 is replaced with a predetermined value lower than No. 24.
At this time, the predetermined value may be the actual output Fr at that time. As described above, the corrected heat amount F immediately reaches the reduced maximum limit value, and thereafter, the calculation of the corrected heat amount F is stopped. Therefore, it is possible to prevent the corrected heat amount F from excessively increasing.

FIG. 3 is a control flow of the control unit 31 in one embodiment of the present invention. First, it is determined whether the vehicle is operating, that is, whether the vehicle is burning (step S1). If the vehicle is burning, it is determined whether the correction heat amount F is increasing (step S2a). If it is not burning in step S1, R
Shift to ETURN. If the correction calorific value has increased in step S2a, it is determined whether the actual output Fr has increased (step S3). Actual output F
If r has increased, the fuel supply pressure has not decreased, and the process shifts to RETURN. If the actual output Fr has not increased in step S3, it is determined that the fuel supply pressure has decreased. Next, it is determined whether or not the corrected heat amount F has reached the maximum limit value (step S4). If the maximum limit has not been reached, the process moves to RETURN. If the maximum limit value has been reached in step S4, the actual output Fr is calculated from equation (3) from the water supply temperature Tc, the hot water supply temperature Th, and the water supply water quantity Q and stored (step S5). Fr = Q × (Th−Tc) Equation (3)

Next, the actual output Fr storing the maximum limit value of the corrected heat amount F is replaced (step S6), and the corrected heat amount F
Is reset (step S7). Next, it is determined whether the operation has been stopped, that is, whether the combustion has stopped (step S8). If the combustion has not been stopped, the required heat amount F
It is determined whether 1 or the correction calorie F has dropped below a predetermined value (step S9). If it has not decreased to the predetermined value, the process proceeds to RETURN. If the combustion is stopped in step S8 or if the required heat amount F1 or the corrected heat amount F is reduced to a predetermined value or less in step S9, the maximum limit value of the corrected heat amount is reset.

FIG. 4 is a control flow of a first modification of the control unit 31 in one embodiment of the present invention. The only difference from FIG. 3 is that the determination by the supply pressure drop detecting means 43 is different, and the other points are the same. That is, step S
2a is replaced by step S2b, and only step S3 is deleted. If the combustion is being performed in step S1, it is determined whether the correction coefficient α (= F1 / F) is equal to or greater than a predetermined value (step S2b). If the correction coefficient α is lower than the predetermined value, the processing shifts to RETURN. If the correction coefficient α is equal to or more than the predetermined value, the process shifts to steps S4 to S5 to calculate and store the actual output Fr. Here, the predetermined value is a fixed value of about 1.5 or a value learned when the corrected heat amount F is low so as not to be affected by the decrease in the fuel supply pressure.

FIG. 5 is a control flow of a second modification of the control section 31 in one embodiment of the present invention. 4 is different from FIG. 4 only in a part of the flow of the determination by the supply pressure drop detecting means 43 and in the order of the flow, and is otherwise the same. In other words, the only difference is that step S2b is replaced with step S2c, and steps S4 and S5 are shifted after step S1. If it is burning in step S1, the correction calorie F
Is determined to have reached the maximum limit value (step S4). If the maximum limit value has been reached, the feedwater temperature T
The actual output Fr is calculated from equation (3) from c, the hot water supply temperature Th and the supplied water quantity Q and stored (step S5). Next, it is determined whether or not the hot water supply temperature Th exceeds a predetermined value (step S2c). If the temperature exceeds the predetermined value, the hot water supply temperature Th is replaced with an actual output Fr that stores the maximum limit value of the corrected heat quantity F (step S6). Reset the correction calorie F (step S
7). If the hot water supply temperature Th is lower than the predetermined value in step S2c, the process proceeds to RETURN. Here, the predetermined value is 60 ° C.
It is set to a fixed value or a value about 10 ° C. higher than the hot water supply set temperature Ts. In FIG. 5, steps S4 and S5 are shifted after step S1 for the following reason.
When the correction heat amount F is calculated so that the hot water supply temperature Th reaches the target hot water supply temperature Ts, if the fuel supply pressure decreases, the correction heat amount F increases so that the hot water supply temperature Th reaches the target hot water supply temperature Ts. At this time, if the required heat amount F1 decreases to a value at which the fuel supply pressure does not decrease due to a decrease in the supply water amount Q or the like, the correction heat amount F increases due to the decrease in the fuel supply pressure, so that the hot water supply temperature Th decreases. Overshoot will occur. That is, since the hot water supply temperature Th overshoots when the required heat amount F1 decreases, the actual output Fr when the corrected heat amount F has reached the maximum limit value is stored in advance.

In the present embodiment, the hot water supply device has only the hot water supply function. However, the hot water supply device has a function of reheating water in the bathtub, and the hot water supply path and the reheating function are constituted by an integrated heat exchanger. Needless to say, the present invention can also be applied to a one-can two-channel water heater. In that case, the required heat amount F1
Is calculated from equation (4). F1 = Q × (Ts−Tc) + F1 ′ Formula (4) Here, F1 ′ is a required heat amount on the reheating side, and a required heat amount F1,
This is a value calculated from the hot water temperature Tf in the bathtub and the like. Further, the correction calorie F is calculated by equation (5). F = (F1 + F1 ′) × α = (F1 + F1 ′) × fPID (Ts−Th) / (Ts−Tc) Equation (5)

[Brief description of the drawings]

FIG. 1 is a configuration diagram in which a water heater according to an embodiment of the present invention is applied to a gas water heater.

FIG. 2 is a control block diagram of a control unit 31 according to an embodiment of the present invention.

FIG. 3 is a control flow of a control unit 31 according to an embodiment of the present invention.

FIG. 4 is a control flow of a first modification of the control unit 31 according to an embodiment of the present invention.

FIG. 5 is a control flow of a second modification of the control unit 31 according to an embodiment of the present invention.

FIG. 6 is a diagram showing a relationship among a corrected heat amount, a proportional valve opening, and a fan speed of a conventional hot water supply device.

FIG. 7 is a diagram showing a relationship between a proportional valve opening degree and a fuel supply amount of a conventional hot water supply apparatus.

[Description of Signs] 9 ... Fan, 19 ... Gas proportional valve, 21 ...
Gas solenoid valve, 25 ... Feed water temperature sensor, 27 ...
Water amount sensor, 29 ... Hot water supply temperature sensor, 31 ...
Control unit, 41: required calorific value calculating unit (required calorific value calculating unit), 42: corrected calorific value calculating unit (corrected calorific value calculating unit), 43: supply pressure drop detecting unit, 44:
Correction calorie limiter ()

Claims (9)

[Claims] 1. A fan for supplying air for combustion to a burner, a proportional control valve for adjusting a fuel supply amount supplied to the burner, and a heater for heating water supplied from a water supply pipe to a hot water supply pipe. A heat exchanger for supplying the water, a water amount sensor for detecting a water supply amount passing through the water supply pipe, a water supply temperature sensor for detecting a water supply temperature of the water supply pipe, and a hot water supply temperature of hot water passing through the water supply pipe. A hot water supply temperature sensor, a required heat amount calculating means for calculating a required heat amount from the target hot water temperature, the supply water temperature, and the supply water amount, and a correction that corrects the required heat amount by at least integral correction so that the hot water temperature becomes equal to the target hot water temperature. In a water heater provided with a correction calorie calculating means for calculating a calorific value, a supply pressure drop detecting means for estimating a decrease in a supply pressure of fuel supplied to the burner is provided, and the supply pressure drop detecting means is provided with a fuel supply A hot water supply apparatus characterized in that when a decrease in supply pressure is detected, the maximum limit value of the corrected heat amount is reduced. 2. The supply pressure drop detection means, when the correction heat quantity is increasing, decreases the fuel supply pressure when the actual output calculated from the feed water temperature, the hot water temperature, and the feed water quantity does not increase. The hot water supply apparatus according to claim 1, wherein it is determined that the hot water supply has been performed. 3. The supply pressure drop detection means determines that the supply pressure of fuel has decreased when a correction coefficient calculated from a ratio between the required heat quantity and the correction heat quantity has increased to a predetermined value or more. The hot water supply device according to claim 1, wherein 4. The hot water supply apparatus according to claim 1, wherein the supply pressure drop detection means determines that the supply pressure of the fuel has dropped when detecting an overshoot of the hot water supply temperature. 5. The hot water supply apparatus according to claim 1, wherein the maximum limit value of the corrected heat amount is determined based on the actual output calculated when the corrected heat amount reaches the maximum value. 6. The hot water supply apparatus according to claim 1, further comprising a maximum limit value correction unit that resets a maximum limit value of the correction heat amount. 7. The hot water supply apparatus according to claim 6, wherein the maximum limit value correction unit resets the maximum limit value of the corrected heat amount when the operation of the water heater is stopped. 8. The hot water supply according to claim 6, wherein the maximum limit value correction means resets the maximum limit value of the corrected heat amount when the required heat amount or the corrected heat amount falls below a predetermined value. apparatus. 9. The hot water supply apparatus according to claim 1, wherein when a decrease in fuel supply pressure is detected, a subtraction process including a reset is performed on the calculated value of the corrected calorific value.