JP2022038953A - Bath water heater - Google Patents

Abstract

To provide a bath water heater capable of suppressing noise generated in a water level sensor while hot water supply operation is performed with intermittent combustion.SOLUTION: A bath water heater comprises: a water level sensor that heats a hot water supply heat exchanger and a reheating heat exchanger with a common heat source, and detects a water pressure of bathtub water; and a control device that controls each unit. In intermittent combustion during single operation for hot water supply, the control device is configured to: when a temperature of high-temperature water is lower than a predetermined temperature, set a required heat generation amount during a combustion period to a first heat amount; and when the temperature of the high-temperature water is equal to or higher than the predetermined temperature, set the required heat generation amount to a second heat amount smaller than the first heat amount.SELECTED DRAWING: Figure 5

Description

The present invention relates to a bath water heater.

Japanese Patent No. 3777005 (Patent Document 1) and Japanese Patent No. 3735891 (Patent Document 2) disclose a one-can, two-water channel type bath water heater. The one-can, two-water channel type bath water heater is configured to heat a heat exchanger for hot water supply and a heat exchanger for reheating with a common burner.

The bath water heater described in Patent Document 1 is a water level sensor for detecting the water level of hot water in a bathtub (hereinafter, also referred to as "bathtub water level") provided in a circulation path for heating hot water in a bathtub. Further prepare. The water level sensor is composed of a pressure sensor and detects the bathtub water level based on the bathtub pressure.

Japanese Patent No. 377705 Japanese Patent No. 3735891

However, in the one-can-two-water channel type bath water heater, the hot water staying in the circulation circuit is also heated during the hot water supply operation alone in which the hot water supply operation is performed with the pump provided on the circulation circuit for reheating stopped. Then, the hot water in the circulation circuit moves. Since the output of the water level sensor contains a lot of noise components due to the movement of the hot water in the circulation circuit, there is a problem that the water level of the bathtub cannot be accurately detected while the hot water supply is independently operated.

In particular, during the hot water supply independent operation by intermittent combustion in which the combustion period and the non-combustion period of the combustion mechanism are repeatedly provided, the amount of heat generated at the start of driving of the combustion mechanism temporarily increases, so that the hot water in the circulation circuit When the temperature of the water reaches a temperature close to boiling, the hot water in the circulation circuit boils, and there is a problem that a lot of noise is generated.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a bath water heater capable of suppressing a noise component contained in an output of a water level sensor. ..

According to an aspect of the present invention, the bath water heater has a heat exchanger for hot water supply, a hot water supply circuit for heating and supplying hot water to low temperature water, a heat exchanger for reheating, and a circulation pump, and is in the bathtub. A circulation circuit that circulates and heats hot water, a combustion mechanism that heats a hot water supply heat exchanger and a reheating heat exchanger by a common heat source, a water level sensor that is connected to the circulation circuit and detects the water pressure of the bath water, and Includes a control device that controls each part. The operation mode of the bath water heater includes a hot water supply operation, and a bath water filling operation and a circulation operation using a circulation circuit. The control device selectively controls the combustion mechanism by continuous combustion in which the combustion mechanism is continuously burned and intermittent combustion in which the combustion period and the non-combustion period of the combustion mechanism are repeatedly provided. In addition, when the temperature of the hot water heated by the heat source is lower than the predetermined temperature during intermittent combustion during the hot water supply independent operation in which the hot water supply operation is performed with the bath water filling operation and the circulation operation stopped. In addition, the combustion mechanism is controlled by the first pattern in which the amount of heat generated during the combustion period is the first amount of heat. During intermittent combustion during hot water supply independent operation, the control device sets the amount of heat generated during the combustion period to the second amount of heat, which is smaller than the first amount of heat, when the temperature of the high-temperature water heated by the heat source is equal to or higher than a predetermined temperature. The combustion mechanism is controlled by the second pattern. Then, at the time of intermittent combustion during the hot water supply independent operation, the control device detects the change in the bathtub water level based on the detection value of the water level sensor.

According to the present invention, when it is determined that the temperature of the high-temperature water heated by the heat source is equal to or higher than a predetermined temperature when intermittent combustion is applied, the amount of heat generated during the combustion period is set to a second calorific value smaller than the first calorific value. Since the combustion mechanism is controlled, it is possible to prevent the temperature of the hot water in the circulation circuit from rising too high. As a result, the noise component included in the output of the water level sensor can be suppressed.

It is a schematic block diagram of the bath water heater 10 according to this embodiment. It is a functional block diagram of the control device 100 shown in FIG. It is a figure which shows the structural example of the 1st filter 162a. It is a figure which shows the structural example of the 2nd filter 162b. It is a flowchart which shows the required heat quantity setting process which the control device 100 executes. It is a figure which shows the control operation example and the time-dependent change of the can body temperature Tb when the combustion mechanism 63 is controlled according to the required heat quantity setting process shown in FIG. It is a figure which shows the setting example of the combustion period. It is a figure which shows the setting example of the combustion period. It is a flowchart for demonstrating the control process of the bath hot water supply device 10 related to the selection of the water level data referred to by the bath entry / exit detection unit 164.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the figure are designated by the same reference numerals, and the description thereof will not be repeated in principle.

[Bath water heater 10]
FIG. 1 is a schematic configuration diagram of a bath water heater 10 according to the present embodiment.

With reference to FIG. 1, the bath water heater 10 according to the present embodiment includes a hot water supply circuit 2, a circulation circuit 4, a combustion mechanism 63, and a control device 100 for controlling the bath water heater 10. The bath hot water supply device 10 according to the present embodiment is a one-can, two-water channel type hot water supply device that heats a hot water supply heat exchanger and a reheating heat exchanger with a common combustion burner.

(Hot water supply circuit 2)
The hot water supply circuit 2 is a circuit for supplying hot water having an appropriate temperature controlled to a hot water supply set temperature when a hot water supply tap such as a curan 190 or a shower is opened. The hot water supply circuit 2 includes a primary heat exchanger 61 and a secondary heat exchanger 62 for hot water supply housed in the can body 6, a water inlet pipe 21, a can body pipe 22, a bypass pipe 23, and a hot water outlet pipe 24. It includes a hot water supply pipe 25, a distribution unit 32, a flow rate adjusting valve 28, a flow rate sensor 51, and temperature sensors 52, 53, 54.

The water inlet pipe 21 is connected to a water supply channel such as a water supply on the upstream side, and the can body pipe 22 and the bypass pipe 23 are connected to the downstream side via the distribution unit 32. Cold water is supplied to the water inlet pipe 21 from the water supply channel. The low-temperature water in the water inlet pipe 21 is distributed to the can body pipe 22 and the bypass pipe 23 via the distribution unit 32.

The distribution unit 32 is configured to be able to adjust the ratio of the flow rate of the low temperature water supplied to the bypass pipe 23 (hereinafter, also referred to as “distribution rate k”) to the flow rate of the low temperature water supplied to the can body pipe 22. .. For example, the distribution unit 32 is a valve, and adjusts the distribution rate k by controlling the valve opening degree according to a control command from the control device 100.

The can body pipe 22 is connected to the secondary heat exchanger 62. The low-temperature water introduced from the water inlet pipe 21 to the can body pipe 22 is first preheated by the secondary heat exchanger 62 and then mainly heated by passing through the primary heat exchanger 61. The high-temperature water heated to a predetermined temperature by the primary heat exchanger 61 and the secondary heat exchanger 62 is discharged from the hot water outlet pipe 24.

The hot water outlet pipe 24 is connected to the bypass pipe 23 at the confluence point 27. That is, at the confluence point 27, the high temperature water output from the can body 6 and the low temperature water from the bypass pipe 23 are mixed. Of the low-temperature water from the water inlet pipe 21, the low-temperature water having a flow rate according to the distribution rate k adjusted by the distribution unit 32 is mixed with the high-temperature water at the confluence 27. That is, the distribution rate k (0 ≦ k ≦ 1.0) is the flow rate supplied to the bypass pipe 23 with respect to the flow rate toward the hot water outlet pipe 24 for supplying hot water (can body flow rate q1) (hereinafter, “bypass flow rate”). It is also referred to as "q2") and is represented by q2 / q1. The distribution rate k is variably controlled by a set temperature or the like. As a result, hot water having a set temperature is supplied to a predetermined hot water supply point such as a hot water faucet such as a curan 190 or a shower or a hot water pouring pipe 26 to a bathtub 8. The hot water outlet pipe 24 is provided with a flow rate adjusting valve 28 for controlling the hot water supply flow rate.

The temperature sensor 52 is arranged in the can body pipe 22 and detects the temperature of low-temperature water (hereinafter, also referred to as “incoming water temperature Tw”). The temperature sensor 53 is arranged on the upstream side (primary heat exchanger 61 side) of the hot water discharge pipe 24 from the confluence point 27, and detects the temperature of high-temperature water (hereinafter, also referred to as “can body temperature Tb”). do. The temperature sensor 54 is arranged in a portion of the hot water pipe 24 on the downstream side of the confluence point 27, and detects the hot water temperature after mixing the hot water and the low temperature water (hereinafter, also referred to as “hot water temperature Th”). The flow rate sensor 51 is arranged in the can body pipe 22 and detects the can body flow rate q1.

(Combustion mechanism 63)
The combustion mechanism 63 has a combustion burner. The combustion burner is composed of, for example, a gun type burner having an injection nozzle 630 for spraying petroleum (kerosene) as a liquid fuel. The combustion mechanism 63 further includes a fuel supply pipe 631, an electromagnetic on-off valve 632, an electromagnetic supply pump 633, a return pipe 634, a flow rate control valve 635, a blower fan 636, and an ignition transformer 637.

The fuel supply pipe 631 guides liquid fuel (hereinafter, also simply referred to as “fuel”) from a fuel tank (not shown) to an injection nozzle 630. The electromagnetic on-off valve 632 is arranged in the fuel supply pipe 631 and opens and closes in response to a control command from the control device 100 to turn on and off the fuel supply to the fuel supply pipe 631. The electromagnetic supply pump 633 is arranged in the fuel supply pipe 631 and boosts the fuel supplied via the electromagnetic on-off valve 632 in the open state in response to a control command from the control device 100. The boosted fuel is injected in a mist form from the injection nozzle 630.

The blower fan 636 supplies combustion air to the combustion burner. The fuel injected from the injection nozzle 630 is mixed with the combustion air from the blower fan 636. By being ignited by the ignition transformer 637, the fuel from the injection nozzle 630 is burned to generate a flame. The combustion heat generated by the flame from the combustion burner is given to the primary heat exchangers 60 and 61 in the can body 6. On the downstream side of the can body 6 in the flow direction of the combustion gas, a chimney 64 for discharging the combustion exhaust gas after heat exchange is provided. The latent heat of the combustion exhaust gas is given to the secondary heat exchanger 62 in the smoke exhaust tube 64.

The return pipe 634 is configured to return a part of the liquid fuel supplied by the fuel supply pipe 631 to the fuel supply pipe 631. A flow rate control valve 635 for controlling the flow rate of the return oil is arranged in the return pipe 634. The valve opening degree of the flow rate control valve 635 is adjusted according to a control command from the control device 100. By adjusting the flow rate of the return oil by the flow rate control valve 635, the amount of fuel sprayed from the injection nozzle 630 is controlled. Basically, the amount of combustion by the combustion burner is proportional to the amount of fuel. Therefore, the amount of combustion by the combustion burner can be controlled by controlling the valve opening degree of the flow rate control valve 635.

(Circulation circuit 4)
The circulation circuit 4 is a circuit for circulating hot water in the bathtub 8 (hereinafter, also referred to as “bathtub water”). The circulation circuit 4 has a primary heat exchanger 60 for reheating and a circulation pump 34 for circulating bath water in the circulation circuit 4. The circulation circuit 4 can also function as a reheating circulation circuit for reheating the bathtub water until it reaches the bath set temperature by circulation. The primary heat exchanger 60 heats the bath water passed through by the combustion heat of the combustion mechanism 63. In addition to the primary heat exchanger 60, the bathtub water may be heated by passing the bathtub water through the secondary heat exchanger.

The bath return pipe 82 and the bath out pipe 83 are connected to the circulation circuit 4. The upstream end of the bath return pipe 82 is connected to the suction method of the circulation adapter 81 installed in the bathtub 8. Further, the downstream end of the bath going pipe 83 is connected to the discharge side of the circulation adapter 81.

When the circulation pump 34 is activated, the bath water circulates from the suction port of the circulation adapter 81 to the discharge port of the circulation adapter 81 via the bath return pipe 82, the primary heat exchanger 60 and the bath going pipe 83. do. The reheating function is realized by heating the bathtub water passing through the circulation circuit 4 by passing through the primary heat exchanger 60.

The circulation circuit 4 further includes a water level sensor 55. The water level sensor 55 is composed of, for example, a pressure sensor, and based on the pressure applied to the piping of the circulation circuit 4 (more specifically, the water pressure in the piping), the water level of the bathtub water in the bathtub 8 (hereinafter, “bathtub water level””. Also called) is detected. Since the water level sensor 55 is configured to detect minute pressure fluctuations, it has a characteristic of being easily affected by noise. Therefore, a filtering process for removing noise from the detection value of the water level sensor 55 is required. The filtering process will be described later.

The bath hot water supply device 10 further includes a hot water pouring pipe 26 for branching from the hot water outlet pipe 24 and filling the bathtub 8 with hot water. The hot water pouring pipe 26 is branched from the hot water outlet pipe 24 via the flow rate adjusting valve 28. The hot water pouring pipe 26 is provided with a hot water pouring on-off valve 29. The pouring pipe 26 is connected to the circulation circuit 4 at the confluence point 26A. By controlling the opening and closing of the hot water pouring on-off valve 29 by the control device 100, it is possible to control the formation / blocking of the path for filling the hot water from the hot water supply circuit 2 to the bathtub 8.

[Operation mode of bath water heater 10]
The operation mode of the bath water heater 10 includes a hot water supply operation, a bath water filling operation, and a circulation operation. The operation mode further includes a stop mode for stopping all of the hot water supply operation, the bath water filling operation, and the circulation operation.

In the hot water supply operation, the low temperature water supplied to the water inlet pipe 21 is supplied to the secondary heat exchanger 62 and the primary heat exchanger 61 via the can body pipe 22. The low-temperature water supplied to the secondary heat exchanger 62 is supplied to the primary heat exchanger 61 after raising the temperature by exchanging heat with the latent heat of the combustion exhaust gas. The low-temperature water after the temperature rise supplied to the primary heat exchanger 61 becomes high-temperature water by exchanging heat with the combustion heat generated in the combustion mechanism 63. This high-temperature water is supplied to a hot water tap such as Karan 190 via a hot water outlet pipe 24 and a hot water supply pipe 25.

In the bath water filling operation, the low temperature water supplied to the water inlet pipe 21 is supplied to the secondary heat exchanger 62 and the primary heat exchanger 61 via the can body pipe 22. The low-temperature water supplied to the secondary heat exchanger 62 is supplied to the primary heat exchanger 61 after raising the temperature by exchanging heat with the latent heat of the combustion exhaust gas. The low-temperature water after the temperature rise supplied to the primary heat exchanger 61 becomes high-temperature water by exchanging heat with the combustion heat generated in the combustion mechanism 63. This hot water is supplied to the bathtub 8 through the hot water outlet pipe 24, the hot water pouring pipe 26, the circulation circuit 4, and the discharge port of the circulation adapter 81.

In the circulation operation, the circulation pump 34 is operated to circulate the bath water through the circulation circuit 4. In the circulation operation, the bath water is sucked up from the suction port of the circulation adapter 81 by the circulation pump 34 in the direction of the arrow in the drawing. The sucked bath water circulates in the path leading to the discharge port of the circulation adapter 81 via the circulation circuit 4 including the primary heat exchanger 60. The reheating operation is executed by heat exchange heating the bathtub water supplied to the primary heat exchanger 60 by the combustion heat generated in the combustion mechanism 63. The circulation operation can include a bubble generation operation and an air purge operation in addition to the reheating operation. The bubble generation operation is an operation mode in which hot water containing fine bubbles is supplied into the bathtub 8 by using the bubble generation function of the circulation adapter 81. The air purge operation is an operation mode in which the air mixed in the circulation circuit 4 is removed by circulating the bathtub water in the circulation circuit 4. In the bubble generation operation and the air purge operation, the combustion mechanism 63 is not burned and the circulation pump 34 is operated to circulate the bath water in the circulation circuit 4.

[Function of control device 100]
Next, the functional configuration of the control device 100 will be described.

The control device 100 controls the operation of the bath water heater 10 by receiving a user operation and a value detected by each sensor. For example, user operations include hot water supply operation, bath water filling operation, and on / off instruction for reheating operation, and setting of hot water supply set temperature and bath set temperature, which are input by operating an operation switch provided on a remote controller (not shown). ..

FIG. 2 is a functional block diagram of the control device 100 shown in FIG. The function of each block in FIG. 2 can be realized by software processing in which the control device 100 executes a program stored in advance. Alternatively, it is also possible to realize a part or all of each block by hardware processing using a dedicated electronic circuit. With reference to FIG. 2, the control device 100 includes an operation control unit 120 and a water level detection unit 160.

(Operation control unit 120)
The operation control unit 120 includes an operation mode setting unit 122, a required heat amount calculation unit 124, a combustion control unit 126, and a distribution rate control unit 128.

The operation mode setting unit 122 manages the start and end (stop) of each operation mode of the hot water supply operation, the bath water filling operation, and the circulation operation. The operation mode setting unit 122 can manage the start and end (stop) of each operation mode so as to be controlled in parallel with a plurality of types of operation modes.

For example, when the operation mode setting unit 122 determines that the amount of water flowing from the water supply channel to the bath hot water supply device 10 exceeds the minimum operating flow rate (MOQ) based on the output of the flow rate sensor, the operation mode setting unit 122 starts the hot water supply operation. Further, when the operation mode setting unit 122 determines that the amount of water flowing from the water supply channel to the bath hot water supply device 10 is less than the minimum operating flow rate (MOQ), the operation mode setting unit 122 stops the hot water supply operation.

The operation mode setting unit 122 starts the bath water filling operation when the on instruction of the bath water filling operation is given by the operation of the operation switch provided on the remote controller. The operation mode setting unit 122 starts the bathtub filling operation, and when the bathtub water level reaches the set water level and the bathtub water temperature detected by the temperature sensor (not shown) reaches the bath set temperature, the bathtub filling operation is performed. To stop. The operation mode setting unit 122 calculates the amount (volume) of the pouring water into the bathtub 8 by integrating the flow rate (pouring flow rate) detected by the flow rate sensor (not shown) arranged in the pouring pipe 26. can do.

The operation mode setting unit 122 starts the circulation operation when the on instruction of the circulation operation is given by the operation of the operation switch provided on the remote controller. In addition, the bath water heater 10 may be set to an automatic mode for maintaining the bathtub water temperature and the bathtub water level after the bath water filling operation is completed. When the automatic mode is set, if the bathtub water temperature detected by the temperature sensor drops below the reference temperature set corresponding to the bath set temperature (for example, set 2-3 ° C lower than the bath set temperature), the operation is performed. The mode setting unit 122 starts the reheating operation. Further, when the bathtub water level detected by the water level sensor 55 drops below the set water level, the operation mode setting unit 122 starts the additional hot water operation of additionally pouring hot water from the bath water heater 10 to the bathtub 8.

If the operation mode setting unit 122 determines to start the circulation operation or the bath water filling operation during the execution of the hot water supply operation, the operation mode setting unit 122 executes the circulation operation or the bath water filling operation at the same time as the hot water supply operation. In the present specification, in the hot water supply operation, the case where neither the circulation operation nor the bath water filling operation is executed is referred to as "hot water supply independent operation".

Although not shown, the operation mode setting unit 122 controls the circulation pump 34, the flow rate adjusting valve 28, the pouring on / off valve 29, and the like according to the start / stop of various operation modes.

The required heat amount calculation unit 124 per unit time required for the bath water heater 10 from the controlled operation mode, target temperature Tr * (set temperature), water inlet temperature Tw, can body flow rate q1, distribution rate k, and the like. The required heat generation amount Qrq, which is the heat amount of, is calculated. As an example, a method of calculating the required heat generation amount Qrq when controlled by at least one of the hot water supply operation and the bath water filling operation will be described.

For the bath water heater 10, the amount of heat for raising the water entry temperature Tw to the target temperature Tr * is generated for the flow rate of water supplied from the water inlet pipe 21 (hereinafter, also referred to as “total flow rate qt”). Is required. Therefore, the required heat generation amount Qrq when controlled by at least one of the hot water supply operation and the bath hot water filling operation can be calculated according to the following equation (1).

Qrq = qt ・ (Tr * -Tw)… (1)
Actually, it is necessary to consider the ratio (thermal efficiency) of the amount of heat generated by the combustion mechanism 63 to the amount of heat used for raising the temperature in the primary heat exchangers 60 and 61 and the secondary heat exchanger 62. In the following, for the sake of brevity, the thermal efficiency is assumed to be 1.0. Further, in a bath water heater, the required amount of heat generated is generally calculated in units of "number". The number = 1 corresponds to the amount of heat required to raise the hot water temperature by 25 ° C. under a flow rate of qt = 1 (L / min).

The total flow rate qt is calculated from the distribution rate k and the can body flow rate q1. Therefore, when the required heat quantity calculation unit 124 is controlled by at least one of the hot water supply operation and the bath hot water filling operation, the water entry temperature Tw from the temperature sensor 52 and the target temperature Tr * are according to the above equation (1). The required heat generation amount Qrq is calculated based on the can body flow rate q1 from the flow rate sensor 51 and the distribution rate k set by the distribution rate control unit 128. The total flow rate qt may be obtained by providing a flow rate sensor on the water inlet pipe 21.

Based on the required calorific value Qrq, the combustion control unit 126 repeats the operating state of the combustion mechanism 63 with continuous combustion in which the combustion period of the combustion mechanism 63 is continuously provided, and the combustion period and non-combustion period of the combustion mechanism 63. Set to either one of the provided intermittent combustion. Then, the combustion control unit 126 generates a control command to the combustion mechanism 63 according to the set operating state.

The combustion control unit 126 determines the operating state of the combustion mechanism 63 when the required heat generation amount Qrq is less than the heat amount that can be continuously and stably generated by the combustion mechanism 63 (hereinafter, also referred to as “minimum heat generation amount Q1”). Set to "intermittent combustion". Here, the minimum amount of heat generated Q1 corresponds to the amount of heat generated when the amount of combustion sprayed from the injection nozzle 630 is set to the lower limit value at which a stable combustion state can be secured, and is predetermined as the capacity of the combustion mechanism 63. ing.

When the operating state of the combustion mechanism 63 is set to continuous combustion, the combustion control unit 126 continuously burns the combustion mechanism 63 so that the amount of heat according to the required amount of heat generated Qrq calculated by the required amount of heat calculation unit 124 is generated. ..

When the operating state of the combustion mechanism 63 is set to intermittent combustion, the combustion control unit 126 controls the combustion mechanism 63 so that the combustion of the combustion mechanism 63 is intermittently executed. That is, the combustion burner of the combustion mechanism 63 is extinguished and reignited so that the combustion period and the non-combustion period are repeatedly provided. When the hot water supply is controlled to the independent operation and the operating state of the combustion mechanism 63 is set to intermittent combustion, the combustion control unit 126 sets the combustion mechanism during the combustion period according to the temperature of the high temperature water warmed by the combustion mechanism 63. The amount of heat generated is set for 63. In the present embodiment, as an example, the combustion control unit 126 sets the amount of heat generated for the combustion mechanism 63 during the combustion period according to the can body temperature Tb.

When the distribution rate control unit 128 is controlled by at least one of hot water supply operation and bath hot water filling operation, the target temperature Tr *, the water entry temperature Tw from the temperature sensor 52, and the can body from the temperature sensor 53. Based on the temperature Tb and the hot water discharge temperature Th from the temperature sensor 54, a control command to the distribution unit 32 for controlling the hot water discharge temperature Th to the target temperature Tr * is generated.

Specifically, the following equation (2) holds between the can body flow rate q1, the bypass flow rate q2, the incoming water temperature Tw, the can body temperature Tb, and the hot water outlet temperature Th. Therefore, the distribution rate control unit 128 can control the distribution rate k (q2 / q1) according to the following equation (3) obtained by modifying the equation (2) and substituting Th = Tr *. can.

q2 ・ (Th-Tw) = q1 ・ (Tb-Th)… (2)
k = q2 / q1 = (Tb-Tr *) / (Tr * -Tw) ... (3)
(Water level detector 160)
The water level detection unit 160 detects a change in the bathtub water level based on the detection value of the water level sensor 55. Since the water level sensor 55 is composed of a pressure sensor, it has a characteristic that it detects even the movement of hot water in the bath return pipe 82 and is easily affected by noise. Therefore, the water level detection unit 160 removes a high-frequency noise component from the detection value of the water level sensor 55. The water level detection unit 160 further detects the entry and exit of a person into the bathtub 8 based on the detected change in the bathtub water level. Specifically, the water level detection unit 160 includes a database 161, a noise reduction unit 162, and a bath entry / exit detection unit 164.

The noise reduction unit 162 has a first filter 162a and a second filter 162b. Both the first filter 162a and the second filter 162b are noise filters for removing high-frequency noise components from the detection values of the water level sensor 55. As will be described later, the first filter 162a and the second filter 162b are different from each other in noise reduction performance and real-time performance. Specifically, the second filter 162b has higher noise reduction performance than the first filter 162a. On the other hand, the second filter 162b has a property that the real-time property is low because the number of data used for the filter processing is larger than that of the first filter 162a.

The first filter 162a performs a filter process on the noise superimposed on the detection value of the water level sensor 55, and outputs the water level data from which the noise is removed to the database. FIG. 3 is a diagram showing a configuration example of the first filter 162a.

As shown in FIG. 3, as the first filter 162a, for example, a moving average filter can be used. The moving average filter is configured to calculate a simple moving average value z [n] of N sampling points x [n] to x [n- (N-1)] in the detected value of the water level sensor 55.

The second filter 162b performs a filter process on the noise superimposed on the detection value of the water level sensor 55, and outputs the water level data from which the noise component is removed to the database. As the second filter 162b, a low-pass filter having a characteristic of attenuating the frequency component in the mid-high range without attenuating the frequency component in the low frequency range can be applied to eliminate the above-mentioned drawbacks of the moving average filter. However, the second filter 162b has a higher noise reduction performance than the first filter 162a, but has a property of low real-time performance because the number of data used for arithmetic processing is large.

FIG. 4 is a diagram showing a configuration example of the second filter 162b. As shown in FIG. 4, for the second filter 162b, for example, a double moving average filter can be used. The double moving average filter is a simple moving average value y [n] of M simple moving average values z [n] to z [n- (M-1)] calculated in each of the M moving average filters. Is configured to calculate. That is, the double moving average filter applies the simple moving average twice.

Returning to FIG. 2, the bath entry / exit detection unit 164 detects the entry / exit of a person into the bathtub 8 by using the water level data generated by the noise reduction unit 162. Specifically, the bath entry / exit detection unit 164 selectively uses either the water level data generated by the first filter 162a or the water level data generated by the second filter 162b to detect bathing / exiting. ..

In the one-can-two-water channel type bath water heater 10, when the water in the hot water supply circuit 2 is heated, the hot water staying in the circulation circuit 4 (hereinafter, also referred to as "retained water") is also heated to take a bath. The hot water in the return pipe 82 moves. Therefore, in the one-can, two-water channel type bath water heater 10, even if the circulation pump 34 is stopped, during the hot water supply independent operation, the hot water supply operation, the bath water filling operation, and the circulation operation are all stopped during the stop mode. In comparison, a lot of noise is added to the output value of the water level sensor 55.

Therefore, the bath entry / exit detection unit 164 selectively selects either one of the water level data generated by the first filter 162a and the water level data generated by the second filter 162b according to the operating condition of the bath hot water supply device 10. Use. As a result, the bath entry / exit detection unit 164 can use the water level data processed by the filter according to the noise generation status. The specific selection method will be described later.

[Control method when intermittent combustion is set during hot water supply independent operation]
When the combustion control unit 126 is set to intermittent combustion, the combustion control unit 126 sets the amount of heat generated for the combustion mechanism 63 during the combustion period according to the temperature of the high-temperature water heated by the combustion mechanism 63.

When set to intermittent combustion, the combustion burner is repeatedly ignited and extinguished. When the combustion burner is ignited, the amount of heat generated temporarily increases. Therefore, even during the hot water supply independent operation (while the circulation pump 34 is stopped), if the temperature of the hot water in the circulation circuit 4 heated by the primary heat exchanger 60 reaches a temperature close to boiling, it is temporary. Due to the large amount of heat generated in the water level, the hot water in the circulation circuit 4 boils and the output of the water level sensor 55 contains a large amount of noise components. In the following, a method of suppressing noise generated when intermittent combustion is set during hot water supply independent operation will be described.

FIG. 5 is a flowchart showing a required heat quantity setting process executed by the control device 100. The required heat amount setting process shown in FIG. 5 is repeatedly executed at predetermined intervals, for example, when controlled to the intermittent combustion mode.

In S10, the control device 100 determines whether or not the can body temperature Tb is lower than the predetermined reference temperature T1.

When the control device 100 determines that the can body temperature Tb is lower than the reference temperature T1 (YES in S10), the control device 100 determines to control the bath water heater 10 in the first pattern (S12), and determines that the required heat amount setting process is performed. To finish. The first pattern is a control pattern in which the amount of heat generated required for the combustion mechanism 63 during the combustion period is the amount of heat A.

When the control device 100 determines that the can body temperature Tb is not less than the reference temperature T1 (NO in S10), that is, when it is determined that the can body temperature Tb is equal to or higher than the reference temperature T1, the bath hot water supply device 10 is used. It is decided to control with two patterns (S14), and the required heat quantity setting process is completed. The second pattern is a control mode in which the amount of heat generated for the combustion mechanism 63 during the combustion period is set to the amount of heat B smaller than the amount of heat A.

In the present embodiment, the temperature of the hot water heated by the combustion mechanism 63 is the can body temperature Tb, which is the temperature of the hot water discharged from the primary heat exchanger 61. The reference temperature T1 is lower than the can body temperature Tb (hereinafter, also referred to as “threshold temperature Ts”) when the temperature of the accumulated water in the primary heat exchanger 60 is close to the boiling point, and is, for example, in the second pattern. Even if the combustion mechanism 63 is controlled, the temperature is such that the can body temperature Tb does not exceed the threshold temperature Ts for a predetermined period. The reference temperature T1 is set, for example, by performing an experiment after determining the calorific value A and the calorific value B.

The amount of heat A and the amount of heat B are equal to or greater than the minimum amount of heat generated Q1. The calorific value A and the calorific value B may be varied according to the target temperature Tr *, or may be fixed values regardless of the target temperature Tr *. By setting the calorific value A and the calorific value B to fixed values regardless of the target temperature Tr *, it is possible to reduce the burden of setting the reference temperature T1, the calorific value A, and the calorific value B.

The temperature of the hot water heated by the combustion mechanism 63 is the temperature of the stagnant water in the primary heat exchanger 60 itself, a parameter that affects the temperature change of the stagnant water in the primary heat exchanger 60, or the primary heat. This is a parameter that varies depending on the temperature change of the accumulated water in the exchanger 60. That is, the switching of the control pattern may be performed according to another temperature instead of the can body temperature Tb. For example, when the temperature sensor is arranged in the vicinity of the primary heat exchanger 60, the control pattern may be switched according to the temperature detected by the temperature sensor. Further, when the boiling prevention thermistor is arranged on a part (bend) of the output side of the primary heat exchanger 60 or the primary heat exchanger 61, the control pattern is switched according to the temperature detected by the boiling prevention thermistor. May be.

FIG. 6 is a diagram showing an example of a control operation when the combustion mechanism 63 is controlled according to the required heat amount setting process shown in FIG. 5 and a change with time of the can body temperature Tb. In the operation example of FIG. 6, it is assumed that the hot water supply independent operation is started by intermittent combustion at time t1. Further, in the operation example of FIG. 6, the combustion period and the non-combustion period are assumed to be the same in the first pattern and the second pattern.

Since the can body temperature Tb is low at the start of hot water supply, the bath hot water supply device 10 is controlled by the first pattern. That is, the combustion mechanism 63 controls the amount of heat A to be generated during the combustion period Ton. When the combustion burner ignites according to the required amount of heat generated, the can body temperature Tb rises. Then, when the non-combustion period Tof is started and the combustion burner is extinguished, the can body temperature Tb drops. Then, after that, when the combustion period Ton is started again, the combustion burner is ignited according to the required amount of heat generated, and the can body temperature Tb starts to rise again. In the example shown in FIG. 6, since the temperature change of the can body temperature Tb is larger in the combustion period Ton than in the non-combustion period Toff, the can body temperature Tb gradually increases.

When the can body temperature Tb reaches the reference temperature T1 at time t2, the control device 100 switches the control pattern to the second pattern. That is, the required amount of heat generated during the combustion period Ton is set to the amount of heat B smaller than the amount of heat A.

When controlled by the second pattern, the amount of heat generated by the ignition of the combustion burner during the combustion period Ton is lower than that when controlled by the first pattern, so that the temperature rise during the combustion period Ton is suppressed. As a result, it is possible to suppress the can body temperature Tb from reaching the threshold temperature Ts, and it is possible to suppress the noise generated in the water level sensor 55 when intermittent combustion is set during the hot water supply independent operation.

As a method of suppressing the can body temperature Tb from reaching the threshold temperature Ts, there is a method of constantly reducing the amount of heat generated for the combustion mechanism 63 during the combustion period. However, if the required amount of generated heat is lowered, the rise in temperature is delayed, and the hot water discharge characteristics are deteriorated. Therefore, in the present embodiment, the required heat generation amount is set high until the can body temperature Tb reaches the reference temperature T1, and the heat generation amount required after the can body temperature Tb reaches the reference temperature T1 is lowered. , Can provide good hot water supply characteristics. As a result, it is possible to suppress an increase in the can body temperature Tb and maintain the hot water discharge characteristics at the same time.

[Distribution rate control during intermittent combustion]
As described above, the distribution rate control unit 128 can control the distribution rate k (q2 / q1) according to the above equation (3). The entry temperature Tw is the temperature of the low temperature water supplied from the water supply, and the fluctuation range is small. On the other hand, as shown in FIG. 6, the can body temperature Tb rises from the start of hot water supply. Therefore, the distribution rate k fluctuates mainly under the influence of the can body temperature Tb.

As shown in FIG. 6, in the first pattern and the second pattern, the can body temperature Tb is higher in the second pattern. Therefore, according to the equation (3), the distribution ratio k is larger in the second pattern than in the first pattern.

In this way, by setting the distribution rate k to be larger in the second pattern than in the first pattern, even if the required amount of heat generated is changed, the hot water supplied to each supply point is supplied. The temperature (hot water temperature Th) can be maintained.

[Other examples of burning and non-burning periods]
In the above embodiment, the combustion period and the non-combustion period are assumed to be the same in the first pattern and the second pattern. By not changing the combustion period Ton and the non-combustion period Tof in this way, the burden on the control device 100 can be reduced.

The combustion period and the non-combustion period may be different between the first pattern and the second pattern. For example, at least one of the combustion period Ton and the non-combustion period Toff may be changed between the first pattern and the second pattern to change the ratio of the combustion period Ton to the non-combustion period Toff (Ton / Toff). ..

7 and 8 are diagrams showing an example of setting the combustion period. With reference to FIG. 7, the combustion period Ton in the first pattern is set to T1, the non-combustion period Toff is set to T2, the combustion period Ton in the second pattern is set to T3 (<T1), and the non-combustion period Toff is set to T2. It may be set. When set in this way, the ratio (Ton / Toff) is higher when the combustion mechanism 63 is controlled in the first pattern (T1 / T2) and when the combustion mechanism 63 is controlled in the second pattern (Ton / Toff). It is larger than T3 / T2). When set in this way, the temperature rise of the can body temperature Tb in the second pattern can be further suppressed.

With reference to FIG. 8, the combustion period Ton in the first pattern is set to T1, the non-combustion period Toff is set to T2, the combustion period Ton in the second pattern is set to T1, and the non-combustion period Toff is set to T4 (> T2). It may be set. When set in this way, the ratio (Ton / Toff) is higher when the combustion mechanism 63 is controlled in the first pattern (T1 / T2) and when the combustion mechanism 63 is controlled in the second pattern (Ton / Toff). It is larger than T1 / T4). When set in this way, the temperature rise of the can body temperature Tb in the second pattern can be further suppressed. Further, when set in this way, the intermittent combustion cycle C including the combustion period and the non-combustion period is such that when the combustion mechanism 63 is controlled in the first pattern (C1), the combustion mechanism 63 is in the second pattern. Is shorter than when is controlled (C2). When set in this way, the ignition frequency in the second pattern is lowered, so that the frequency at which the accumulated water in the primary heat exchanger 60 is suddenly warmed when the can body temperature Tb is equal to or higher than the reference temperature T1 is lowered. It is possible to further suppress the generation of noise.

[How to select water level data]
FIG. 9 is a flowchart for explaining the control process of the bath water heater 10 related to the selection of the water level data referred to by the bath entry / exit detection unit 164. The control process shown in FIG. 9 can be executed by, for example, the control device 100.

With reference to FIG. 9, when the control device 100 acquires the detected value by the water level sensor 55 in step S01, the control device 100 generates water level data by performing a filtering process using the first filter 162a in step S02. The control device 100 further performs a filtering process using the second filter 162b in step S03 to generate water level data.

When the water level data by the first filter 162a and the second filter 162b is generated, the control device 100 determines the operation mode of the bath hot water supply device 10 by the processing of steps S04 to S09, and the operation mode is determined according to the determined operation mode. Select which filter to use the water level data or not to refer to the water level data.

Specifically, the control device 100 determines in step S04 whether or not the bath water heater 10 is in the circulation operation. When it is determined that the circulation operation is in progress (when YES is determined in S04), the control device 100 proceeds to step S13 and does not refer to the water level data.

When it is determined that the bath water heater 10 is not in the circulation operation (NO determination in S04), the control device 100 proceeds to step S05 and determines whether or not the bath water heater 10 is in the bath water filling operation. .. When it is determined that the bath water filling operation is in progress (when YES is determined in S05), the control device 100 does not refer to the water level data in step S13.

When it is determined that the bath water heater 10 is not in the bath water filling operation (NO determination in S05), the control device 100 determines whether or not the current timing is within D seconds from the end of the hot water supply operation in step S06. To judge. If the current timing is within D seconds from the end of the hot water supply operation (when YES is determined in S06), the control device 100 makes the water level data inaccessible by step S13. The D second is determined by a preliminary experiment.

On the other hand, if the current timing is not within D seconds from the end of the hot water supply operation (at the time of NO determination in S06), the control device 100 determines in step S07 whether or not the bath hot water supply device 10 is in the hot water supply operation. do. When it is determined that the bath hot water supply device 10 is not in the hot water supply operation, that is, in the stop mode in which all of the circulation operation, the bath water filling operation, and the hot water supply operation are stopped (at the time of NO determination in S07), the control device 100 , Step S11, and the water level data generated by the first filter 162a will be used.

On the other hand, when the bath hot water supply device 10 is in the hot water supply operation (when YES is determined in S07), the control device 100 proceeds to step S08 and determines whether or not the current timing is when the number of hot water supply capacity stages is switched. When the current timing is when the number of hot water supply capacity stages is switched (YES determination in S08), the control device 100 makes it impossible to refer to the water level data in step S13.

When the current timing is not when the number of hot water supply capacity stages is switched (NO determination in S08), the control device 100 further determines in step S09 whether or not intermittent combustion is in progress. When it is determined that intermittent combustion is in progress (when YES is determined in S09), the control device 100 proceeds to step S12 and uses the water level data generated by the second filter 162b.

On the other hand, if it is determined that the combustion is not intermittent, that is, the continuous combustion is in progress (NO determination in S09), the control device 100 further determines in step 10 whether or not the required heat generation amount Qrq is the heat amount C or less. To judge. The calorific value C is a determination value experimentally set according to the magnitude of noise generated in the water level data.

When the requested heat generation amount Qrq is larger than the heat amount C, the control device 100 proceeds to step S13 with step S10 as a NO determination, and makes the water level data unreferenceable.

When the requested heat generation amount Qrq is the heat amount C or less (when YES determination in S10), the control device 100 proceeds to step S12 and uses the water level data generated by the second filter 162b.

Even if the second filter 162b, which has high noise reduction performance, is used during circulation operation, bath water filling operation, within D seconds from the end of hot water supply use, switching of hot water supply capacity stages, and when the required heat generation amount Qrq is larger than the heat amount C. There is too much noise to be generated, and the noise component cannot be sufficiently removed. Therefore, in order to avoid erroneous detection of the bathtub water level in the operating situation where the noise component cannot be sufficiently removed even by using the second filter 162b having high noise removing performance as described above, the control device 100 is used. , The water level data cannot be referred to.

In the operating situation where the noise of the water level data is smaller than the above operating situation, there is a case where the required heat generation Qrq is calorie C or less during the intermittent combustion in the hot water supply independent operation and the continuous combustion in the hot water supply independent operation. included. In this operating situation, the second filter 162b is used to remove noise from the water level data.

Operating conditions in which the water level data contains almost no noise include a stop mode in which all of the hot water supply independent operation, the bath water filling operation, and the circulation operation are stopped. In the stop mode, the first filter 162a is used to remove noise from the water level data.

If the can body temperature Tb becomes equal to or higher than the threshold temperature Ts during intermittent combustion in the hot water supply independent operation, too much noise is generated even if the second filter 162b having high noise reduction performance is used, and the noise component is sufficiently removed. Can't. In the present embodiment, when the can body temperature Tb becomes equal to or higher than the reference temperature T1 so that the can body temperature Tb does not exceed the threshold temperature Ts during intermittent combustion in the hot water supply independent operation, the occurrence required during the combustion period. Reduce the amount of heat. As a result, the water level data can be referred to even during intermittent combustion in the hot water supply independent operation.

As described above, in the bath water heater according to the present embodiment, a second filter having high noise reduction performance is used at the time of intermittent combustion in the hot water supply independent operation. Therefore, the accuracy of detecting the bathtub water level can be improved.

More specifically, the bath water heater according to the present embodiment selectively uses one of a plurality of filters having different noise reduction performance and real-time performance depending on the operation mode of the bath water heater. Then, the filtering process for the output of the water level sensor is executed. The plurality of filters include a first filter and a second filter having higher noise reduction performance than the first filter but lower real-time performance, and the noise generated at the output of the water level sensor is relatively small. The first filter is used in the operation mode, and the second filter is used in the operation mode in which the noise is relatively large. By properly using the two types of filters according to the noise generation status in this way, it is possible to achieve both accuracy and real-time performance of bathtub water level detection. As a result, even in the detection of bathing in and out based on the change in the bathtub water level, the real-time performance can be ensured while maintaining the accuracy of the detection, so that the deterioration of the user's usability can be suppressed.

[Other variants]
In the above-described embodiment, the example in which the can body 6 is composed of the combustion mechanism 63 using petroleum as fuel is shown, but the energy source for heating can be arbitrary.

In the present embodiment, an example in which the water level data from which noise has been removed is used for detecting bathing in and out of the bath has been shown, but the water level data from which noise has been removed is added and used for other functions such as starting hot water operation. You may.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

2 Hot water supply circuit, 4 Circulation circuit, 10 Bath hot water supply device, 53 Temperature sensor, 55 Water level sensor, 60, 61 Primary heat exchanger, 63 Combustion mechanism, 100 Control device, 122 Operation mode setting unit, 126 Combustion control unit, 162 Noise Removal unit, 162a first filter, 162b second filter, 164 bath entry / exit detection unit.

Claims (5)

It ’s a bath water heater,
A hot water supply circuit that has a heat exchanger for hot water supply and heats low-temperature water to supply hot water.
It has a heat exchanger for reheating and a circulation pump, and has a circulation circuit that circulates and heats the hot water in the bathtub.
A combustion mechanism that heats the hot water supply heat exchanger and the reheating heat exchanger with a common heat source, and
A water level sensor connected to the circulation circuit and detecting the water pressure of the bathtub water,
Equipped with a control device to control each part
The operation mode of the bath water heater includes a hot water supply operation, and a bath water filling operation and a circulation operation using the circulation circuit.
The control device is
The combustion mechanism is selectively controlled by continuous combustion in which the combustion mechanism is continuously burned and intermittent combustion in which the combustion period and the non-combustion period of the combustion mechanism are repeatedly provided.
When the temperature of the high-temperature water heated by the heat source is lower than a predetermined temperature during the intermittent combustion during the hot water supply independent operation in which the hot water supply operation is performed with the bath water filling operation and the circulation operation stopped. The combustion mechanism is controlled by the first pattern in which the amount of heat generated during the combustion period is the first amount of heat.
When the temperature of the high-temperature water is equal to or higher than the predetermined temperature during the intermittent combustion during the hot water supply independent operation, the second calorific value is smaller than the first calorific value during the combustion period. The combustion mechanism is controlled by a pattern,
A bath hot water supply device that detects a change in the bathtub water level based on the detection value of the water level sensor during the intermittent combustion during the hot water supply independent operation. The ratio of the combustion period to the non-combustion period is larger when the combustion mechanism is controlled in the first pattern than when the combustion mechanism is controlled in the second pattern. The bath water heater according to 1. The intermittent combustion cycle including the combustion period and the non-combustion period is when the combustion mechanism is controlled in the first pattern than when the combustion mechanism is controlled in the second pattern. The short, bath water heater according to claim 1 or 2. It is further equipped with a temperature sensor that detects the temperature of the hot water discharged from the hot water heat exchanger.
The bath water heater according to any one of claims 1 to 3, wherein the temperature of the hot water is the temperature of the hot water discharged detected by the temperature sensor. The control device is
Water level data is generated by filtering the detected value of the water level sensor, and a change in the water level in the bathtub is detected based on the generated water level data.
It has a first filter and a second filter having higher noise reduction performance than the first filter, and performs a filtering process using the second filter during the intermittent combustion during the hot water supply independent operation. The bath water heater according to any one of claims 1 to 4.

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