JP3087207B2 - Circulating bath kettle controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced circulation bath for heating the circulated water by forcibly circulating water in a bathtub, and more particularly to controlling the circulation bath. The present invention relates to a control device.

[0002]

2. Description of the Related Art Conventionally, water in a bathtub is forcibly circulated by a pump and a heat exchanger provided in a circulation line is heated by combustion to raise the water in the bathtub to a predetermined temperature. A forced circulation bath is used. FIG. 3 shows an example of a heat exchanger for heating water in a pipeline by gas combustion.
FIG. The water F circulated by the pump is sent to the heat exchanger 50 provided at the upper part of the gas combustion chamber 31, where it is reciprocated a plurality of times and returned to the bathtub. That is, water F
Enters the lower pipe 41a from the right end of the heat exchanger 50, goes to the left end of the heat exchanger 50, and
To return to the right end. Then, it goes to the left end by the lower pipe 41c and returns to the right end by the middle pipe 42a. The water F is repeatedly returned to the outside through the upper pipe 43c and returned to the bathtub.

[0003] In a normal forced-circulation bath kettle, the circulating flow rate of water F is 5 to 8 liter / min, and the amount of water in the bathtub is 18
0-200 liters, gas burning amount about 12000kc
al / hour. Water circulation flow rate 5 liter / m
In the case of “in”, the water temperature rises by about 30 degrees Celsius between entering and leaving the heat exchanger 50 (hereinafter, Celsius is omitted). Thus, the bathtub water temperature gradually rises due to the forced circulation heating. The temperature of the water in the bathtub is controlled by the gas combustion chamber 3
It is detected by a thermistor provided up to 1.
Then, when the thermistor detects a predetermined temperature, the forced circulation and the gas combustion are automatically stopped.

[0004]

However, the conventional circulating bath kettle and its control device have the following problems. (1) When the flow velocity in the pipeline is low, there is a problem that partial boiling of water F occurs in the pipeline in the heat exchanger. For example, consider a case in which a circulation bath is started when the temperature of water F in a bathtub is about 10 degrees. Water F flowing into the heat exchanger
The water temperature is about 10 degrees, but the circulating water volume is 5 liters / m
In the case of in, the water temperature of the water F flowing out of the heat exchanger is about 30
It rises to about 40 degrees. When the temperature of the water F in the bathtub rises to about 40 degrees, the water F flowing into the heat exchanger
Is about 40 degrees, and the temperature of the water F flowing out of the heat exchanger is as high as about 70 degrees.

On the other hand, water F in the copper pipe of the heat exchanger
Water temperature is not uniform. This is because the water F circulated by the pump is heated from the outer peripheral side in contact with the inner wall of the copper pipe in the pipeline. For this reason, the water temperature of the water F in the copper pipe has considerable unevenness, and the above-mentioned outflow water temperature is a kind of average water temperature. And when the average water temperature is close to 70 degrees,
The water temperature near the inner wall of the copper pipe near the heat exchanger outlet can reach 100 degrees. At this time, a so-called partial boiling occurs in which the water near the inner wall of the pipe partially boils. When partial boiling occurs, the pressure in the copper pipe of the heat exchanger rises, and there is a problem that the durability of the copper pipe is reduced. In addition, an unpleasant noise (so-called "biting noise") is generated from the heat exchanger, and this noise can be heard from the bathroom. Absent. In addition, high-temperature hot water may flow into the bathtub without eliminating such non-uniform water temperature, and there is a problem when a person enters the bathtub.

(2) Conversely, if the flow velocity in the pipeline is too high, there is a problem that the copper pipes for heat exchange and water droplets generated around the fins are corroded. For example,
Consider a case where the circulation bath is started when the temperature of the water F in the bathtub is about 10 degrees in winter or the like. When the circulating water volume is 8 liters / min, the water temperature in the lower pipe is 10 degrees, but the temperature of the flue gas is as high as about 1300 degrees immediately after combustion, so the surface of the heat exchange fins of the lower copper pipe is 1
It becomes 50 to 180 degrees, and does not become lower than the dew point temperature (for example, 55 degrees) of the combustion exhaust gas.

However, the water temperature in the upper pipe 43c near the outlet of the gas combustion chamber 31 becomes about 29 degrees, and the outer wall temperature of the copper fin becomes lower than the dew point temperature of the combustion exhaust gas. That is, when the temperature of the flue gas is lowered by successive heat exchange and comes into contact with the upper pipe 43, the temperature becomes about 200%.
Because it is a degree. On the other hand, in the case of propane gas used as a combustion gas, a large amount of water is generated by combustion, and a large amount of water is contained in a combustion exhaust gas that comes into contact with a copper pipe or the like. Therefore, there has been a problem that nitrogen oxides and sulfur oxides, which are easily contained in the combustion exhaust gas, dissolve in the water droplets and corrode copper pipes and fins.

According to the present invention, even when the temperature of the water in the bathtub rises, partial boiling does not occur in the heat exchanger, and the circulation of the heat exchanger prevents the durability from being lowered, the generation of abnormal noise, or the inflow of hot water into the bathtub. It is an object of the present invention to provide a bathtub controller.
Another object of the present invention is to provide a circulating bath kettle control device in which water droplets are not generated on the outer wall of a copper pipe or the like in a combustor even in winter, and the copper pipe or the like is not corroded. I do.

[0009]

In order to achieve the above object, a circulation bath controller of the present invention is provided with a forced circulation device for forcibly circulating water in a bathtub, and a forced circulation device provided in the pipeline of the forced circulation device. A circulation bath controller for controlling a circulation bath having a heat exchanger and a gas combustor for heating the heat exchanger, and a circulating water temperature measuring means for measuring a water temperature entering a forced circulation device. The maximum allowable flow rate calculating means for calculating the maximum allowable flow rate from the value measured by the circulating water temperature measuring means, the flow rate measuring means for measuring the flow rate of water flowing through the circulation pipeline, and the flow rate of water circulated by the forced circulation device. Flow rate changing means for changing the flow rate, partial boiling determining means for determining whether the flow rate measured by the flow rate measuring means is the minimum allowable flow rate at which partial boiling of water can occur in the pipeline, and flow rate by the partial boiling determining means. The measuring means To increase the flow rate of water when the measured flow rate is determined to be equal to or less than the minimum allowable flow rate, and to decrease the flow rate of water when the flow rate measured by the flow rate measuring means is determined to be equal to or greater than the maximum allowable flow rate, Flow rate control means for controlling the flow rate variable means.

[0010] In the above-mentioned circulating bath water heater control device, the flow rate measuring means includes an inlet water temperature detector for detecting a temperature of water flowing into the heat exchanger from the bathtub, and an outlet water temperature detector for measuring a temperature of water heated and returned to the bathtub. This is to calculate the flow rate from the vessel. Further, in the above-mentioned circulating bath kettle controller, the flow rate measuring means calculates the flow rate from the number of revolutions of the forced circulation device.

[0011]

The circulating bath kettle of the circulating bath kettle control apparatus according to the present invention having the above-described structure circulates and heats the water in the bathtub through a heat exchanger. The flow rate measuring means measures the flow rate of the circulating water. The flow rate changing means changes the flow rate of water circulated by the forced circulation device. The maximum allowable flow rate calculating means calculates a maximum allowable flow rate from the value measured by the circulating water temperature measuring means. The partial boiling determination means determines whether or not the flow rate detected by the flow rate detection means is a flow rate at which partial boiling of water can occur. When it is determined that the flow rate is equal to or less than the minimum allowable flow rate at which partial boiling can occur, the flow rate control means increases the flow rate circulated by the forced circulation device via the flow rate variable means. Thus, while reducing the rise in water temperature in the heat exchanger,
Reduce the unevenness of water temperature in the pipeline.

Further, the flow control means controls the flow variable means so as to reduce the flow rate of the water when the measured flow rate is equal to or more than the maximum allowable flow rate. As a result, even when the temperature of the bathtub is rising, the outlet water temperature can be prevented from rising excessively and can be maintained at a predetermined temperature or less, so that the occurrence of partial boiling in the copper pipe is eliminated, and the durability is lowered. And generation of abnormal noise can be prevented. In addition, even when the water temperature is low in winter, the outlet temperature of the water can be quickly maintained at or above the predetermined temperature, so that the outer wall temperature of the copper pipe or the like can be maintained at or above the dew point of the combustion gas, and water drops on the outer wall of the copper pipe or the like. It does not stick.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a circulating bath controller according to an embodiment of the present invention; FIG. 1 shows the overall configuration of the circulation bath kettle. The bathtub 24 stores a certain amount of water F. A bath adapter 45 is formed below the inner wall of the bathtub 24 to allow the water F to flow in and out. A return pipe 27 is provided at the center of the bus adapter 45.
Is connected. The return pipe 27 is connected to a pump 15 for circulating water. The pump 15 is connected to a pump drive circuit 32 for controlling the amount of circulating water. At a position upstream of the pump of the return pipe 27, a bathtub water temperature thermistor 26 for detecting the water temperature in the bathtub is attached. Downstream of the pump 15, a flow sensor 33 for measuring the flow rate of the circulating water is attached. The return pipe 27 is connected to the heat exchanger 5 provided at the upper part of the gas combustion chamber 31.
0 has been introduced.

The copper pipe 28 provided in the heat exchanger 50
Is constructed by reciprocating a plurality of times from the end to the end of the heat exchanger 50 as shown in FIG. That is, the copper pipe 28 is connected to the lower pipes 41a, 41b, 4
1c, middle pipes 42a and 42b, upper pipe 43a,
It reciprocates four times in the heat exchanger 50 by 43b and 43c. On the outer wall of the copper pipe 28, there are provided copper fins 21 for heat collection.
Are formed. In the circulating bath kettle of this embodiment, the standard flow rate of the water F is 6.5 liter / min, the amount of water in the bathtub is 180 to 200 liters, and the heat of combustion of gas is about 12000 kcal / hour. At this time, the water temperature rises by about 25 degrees when entering and exiting the heat exchanger 50. The copper pipe 28 exiting the heat exchanger 50 is connected to an outgoing pipe 25 for returning circulating water to the bathtub. Outgoing pipe 25
Is connected to the outer periphery of the return pipe 27 of the bus adapter 45.

Next, the flow path of propane gas G as a combustion gas will be described. The gas pipe 29 is connected to a propane gas tank (not shown). The gas pipe 29 is connected to the main solenoid valve 13 which is a main plug of the instrument. Gas pipe 29
Is introduced into the gas combustion chamber 31. Gas combustion chamber 3
A nozzle 18 for ejecting the gas G is formed at the lower end of the gas pipe 29 at the lower end of the gas pipe 29. Nozzle 1
A burner 17 is fixedly provided in the ejection direction of the nozzle 8. An electrode 16 for generating a spark that ignites the gas G is provided near the upper portion of the burner 17. Gas combustion chamber 31
An air duct 30 is attached to the lower right side of the air conditioner. The blower duct 30 is provided with a fan 12 for supplying combustion air. The fan 12 is connected to a fan motor drive circuit 11. An exhaust top 23 for discharging combustion exhaust gas is formed on the upper right side of the gas combustion chamber 31.

Next, FIG. 2 is a block diagram showing the configuration of the circulation type bath kettle control device of the present embodiment. The controller 35, which is a main part of the control device, includes a CPU 36 for performing arithmetic processing, a ROM 37 for storing a control program, and a RAM 38 for temporarily storing data and the like. ROM37
The water flow variable program 48 for controlling the flow rate of the water F, the maximum allowable flow rate calculation program 51 for calculating the maximum allowable flow rate from the output of the bathtub water temperature thermistor 26, and the minimum flow rate at which partial boiling occurs from the output of the bathtub water temperature thermistor 26 A partial boiling determination program 52 for calculating the flow rate is stored. The controller 35 has a flow sensor 33 as an input.
And a bathtub temperature thermistor 26 are connected. As outputs, a pump drive circuit 32 for controlling the pump 15, a fan motor drive circuit 11 for controlling the fan 12, and the original solenoid valve 13 are connected.

Next, the operation of the circulating bath kettle control device having the above-described configuration will be described. Fill the bath with water F to an appropriate depth. Next, switch on the controller 35 is turned on,
Start gas combustion. That is, the controller 35 opens the original solenoid valve 13 and jets a certain amount of propane gas G from the nozzle 18 to the burner 17. At the same time, a voltage is applied to the electrode 16 and a spark is generated to ignite the burner. Also, the fan motor drive circuit 11
To drive the combustion air to the gas combustion chamber. Further, in response to a command from the controller 35, the pump drive circuit 32
The pump 15 is driven at a constant rotation speed m to circulate a constant flow of water F through the copper pipe 28 in the heat exchanger 50.

A controller 35 which is a main part of the present invention
Is the upstream upper pipe 4 that goes out of the gas combustion chamber 31 based on the detection value of the flow rate sensor 33 that is fed back.
The flow rate of the water F is controlled so that the temperature of the water F flowing in the inside 3c does not become lower than 40 degrees. Further, the controller 35, which is a main part of the present invention, controls the flow rate of the circulating water so that the temperature of the water f flowing in the pipe is lower than the temperature at which partial boiling occurs. That is, in the circulating bath kettle of the present embodiment, when this temperature exceeds 65 degrees, the maximum water temperature in the copper pipe 28 reaches 100 degrees and partial boiling occurs.

Next, the control method will be described with reference to the flowchart shown in FIG. When the circulating bath kettle is started to be fired, the controller 35 measures the circulating water temperature Ti by the circulating water temperature thermistor 26 (S
1). Next, the maximum flow rate calculated by the maximum flow rate calculation program 51 is calculated in the RAM 38 of the controller 35 (S2). Here, the maximum flow rate calculation program 51
Is based on the circulating flow rate-circulating water temperature relationship graph shown in FIG. FIG. 6 shows the circulation flow rate (liter / m) on the vertical axis.
in) and the horizontal axis indicates the circulating water temperature (degrees), and the curve shown in the graph is the circulating water temperature curve. Therefore, if the circulating water temperature is known, the intersection of the circulating water temperature and the circulating water temperature curve is the allowable maximum circulation flow rate at the circulating water temperature. In practice, the flow rate in the lower right part of the circulating water temperature curve at a circulating water temperature of 40 ° C. is such that the outer wall temperature of the pipe immediately before the copper pipe 28 exits the heat exchanger 50 is maintained at a dew point of 55 ° C. or more. Is determined.

Here, as an example, consider a case where a bath is heated by a circulating bath kettle from a state where the water temperature is 5 degrees. At the beginning, the flow rate of the pump 15 is the standard flow rate N = 6.5 liter / min. However, from the graph of FIG. 6, the maximum flow rate when the outlet water temperature is 40 degrees and the inlet water temperature is 5 degrees is about 4 liters / min. Current flow rate measured by the flow rate sensor 33 (S3)
Is larger than the maximum flow rate (S4, Yes), so the rotational speed of the pump is reduced (S5). When the current flow rate becomes lower than the maximum flow rate by continuing the circulating heating, (S4,
No), proceed to the next without changing the rotation speed of the pump 15. Thereby, even if the water temperature is low in winter, the circulating water temperature To can be quickly maintained at 40 ° C. or higher, so that the outer wall temperature of the copper pipe 28 and the fins 21 can be maintained at the dew point temperature of the combustion exhaust gas or more, and the copper pipe No water droplets adhere to the outer walls of the fins 21 and the fins 21. Further, the copper pipe 28 and the fins are not corroded due to the dissolution of sulfur oxide or the like in the water droplets.
Next, the minimum flow rate at which partial boiling does not occur at the current inlet water temperature is calculated by the partial boiling determination program 52 (S6). Then, when the flow rate decreases and becomes equal to or less than the minimum flow rate (S7, Yes), the rotation speed of the pump is increased to prevent occurrence of partial boiling (S8). When the flow rate is larger than the minimum flow rate (S7, No), the process proceeds to the next without changing the rotation speed of the pump 15.

Next, a description will be given of a circulating bath kettle control device according to a second embodiment. The basic configuration and operation are the same as those of the circulating bath kettle control device of the first embodiment, and therefore only different points will be described, and description of the same portions will be omitted. The feature of the second embodiment is, as shown in FIG. 5, a method for controlling the flow rate between the pump 15 and the heat exchanger 50 as a method for increasing or decreasing the flow rate of the water F flowing in the copper pipe 28. The point is that a water control valve 46 which is a control valve is provided. The water control valve 46 is
For example, it is a flow control valve in which a gap between the valve seat and the valve body is changed by moving the valve body by a motor so that water F of an arbitrary flow rate flows. In this case, the output of the pump 15 is fixed, and the flow rate of the water F flowing through the copper pipe 28 is controlled by the controller 35 by the flow rate control program
The flow rate of the water control valve 46 is controlled via 7. According to this embodiment, since the pump can be operated at a constant level as compared with the first embodiment, there is an advantage that control becomes easy.

Next, a description will be given of a recirculating bath kettle controller according to a third embodiment. The basic configuration and operation are the same as those of the circulating bath kettle control device of the first embodiment, and therefore only different points will be described, and description of the same portions will be omitted. The feature of the third embodiment is that the tapping water temperature thermistor 14 is attached to the outflow pipe 25 as shown in FIG. Since the flow rate can be calculated from the water temperature entering and leaving the combustion chamber 50 using FIG. 6, the flow sensor can be omitted. According to this embodiment, the flow sensor 33 can be omitted as compared with the first and second embodiments, so that there is an advantage that the cost can be reduced.

Next, a description will be given of a recirculating bath kettle control device according to a fourth embodiment. The basic configuration and operation are the same as those of the circulating bath kettle control device of the first embodiment, and therefore only different points will be described, and description of the same portions will be omitted. A feature of the fourth embodiment is that the pump drive circuit 32 also has a function of detecting the rotation speed of the pump 15. The detected rotation speed of the pump 15 is input to the controller 35, and the controller 35 calculates a flow rate by multiplying this by a proportional constant.
The flow rate is selected to be proportional to the pump speed. At the same time, the controller 35 is
8, the output of the pump 15 is adjusted via the pump drive circuit 32, whereby the flow rate of the water F flowing in the copper pipe 28 is controlled. Therefore, the flow sensor 33 is unnecessary as shown in FIG. According to this embodiment, since the flow rate is directly detected from the rotation speed of the pump 15 as compared with the first embodiment, the flow rate sensor 33 becomes unnecessary, and the tapping temperature thermistor 14 can be omitted, so that the cost can be reduced. it can. Further, since the signal of the rotation speed of the pump 15 is directly fed back, there is an advantage that the control is ensured.

Although the present invention has been described with reference to several embodiments, the present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the spirit of the present invention. Some things are easy to guess. For example, in the present embodiment, the method of changing the rotation speed of the pump and the method of controlling by the motor flow rate control valve have been described as the flow rate control method, but the gap between the valve body and the valve seat is changed by changing the voltage applied to the coil. A method using a voltage proportional valve for changing the voltage may be used.

[0025]

As is apparent from the above description, the circulation bath controller of the present invention comprises a circulating water temperature measuring means for measuring the water temperature entering the forced circulation device, and a value measured by the circulating water temperature measuring means. A maximum allowable flow rate calculating means for calculating a maximum allowable flow rate, a flow rate measuring means for measuring a flow rate of water flowing through a circulation pipe, a flow rate varying means for changing a flow rate of water circulated by a forced circulation device, and a flow rate measurement Means for judging whether or not the flow rate measured by the means is the minimum allowable flow rate at which partial boiling of water can occur in the pipeline; and the flow rate measured by the flow rate measuring means by the partial boiling judgment means is the minimum allowable flow rate. When the flow rate is determined to be equal to or less than the flow rate, the flow rate of the water is increased so that the flow rate of the water is decreased. Since the outlet temperature can be maintained at a predetermined temperature or more even when the water temperature is low in winter, the outer wall temperature of a copper pipe or the like can be maintained at or above the dew point of the combustion exhaust gas. Water droplets do not adhere to the outer walls of copper pipes and the like, so that sulfur oxides and the like do not dissolve in the water droplets to form sulfuric acid and the like, so that copper pipes and the like are not eroded, and partial boiling occurs in the heat exchanger. Thus, it is possible to prevent deterioration of durability, generation of abnormal noise, or inflow of high-temperature hot water into the bathtub.

[Brief description of the drawings]

FIG. 1 is a drawing showing a configuration of a circulation type bath kettle control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a circulation bath kettle control device according to the first embodiment.

FIG. 3 is a sectional view showing a configuration of a combustor.

FIG. 4 is a flowchart showing the operation of the circulation type bath kettle control device of the first embodiment.

FIG. 5 is a drawing showing a configuration of a circulating bath kettle control device according to a second embodiment.

FIG. 6 is a graph showing a relationship between an outlet temperature and a flow rate for each inlet temperature in a combustor of a circulation type bath kettle control device.

FIG. 7 is a diagram showing a configuration of a circulation type bath kettle control device according to a third embodiment.

FIG. 8 is a drawing showing a configuration of a circulation type bath kettle control device according to a fourth embodiment.

[Explanation of symbols]

 14 Hot Water Thermistor 15 Pump 24 Bath 26 Bath Water Temperature Thermistor 28 Copper Pipe 31 Gas Combustion Chamber 32 Pump Drive Circuit 33 Flow Rate Sensor 35 Controller 46 Water Control Valve 47 Flow Rate Control Circuit 48 Water Volume Variable Program 50 Heat Exchanger 51 Maximum Flow Rate Calculation Program 52 Partial boiling determination program

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-204062 (JP, A) JP-A-6-147633 (JP, A) JP-A-6-317349 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) F24H 1/00 602

Claims (3)

(57) [Claims] 1. A circulating bath having a forced circulation device for forcibly circulating water in a bathtub, a heat exchanger provided in a pipeline of the forced circulation device, and a gas combustor for heating the heat exchanger. In a circulation type bath water heater control device for controlling a water heater, a circulating water temperature measuring means for measuring a water temperature entering the forced circulation device, and a maximum allowable flow rate calculating means for calculating a maximum allowable flow rate from a value measured by the circulating water temperature measuring means. Flow rate measuring means for measuring a flow rate of water flowing through a circulation pipeline, a flow rate varying means for changing a flow rate of water circulated by the forced circulation device, and a flow rate measured by the flow rate measurement means within the pipeline. A partial boiling determination means for determining whether or not the minimum allowable flow rate at which partial boiling of water can occur; and a flow rate measured by the flow rate measurement means by the partial boiling determination means is equal to or less than the minimum allowable flow rate. Flow rate control for controlling the flow rate varying means so as to increase the flow rate of water when determined, and to reduce the flow rate of water when determined that the flow rate measured by the flow rate measuring means is equal to or more than the maximum allowable flow rate. Means for controlling the circulation of the bathtub. 2. The apparatus according to claim 1, wherein the flow rate measuring means detects an inlet water temperature detector for detecting a temperature of the water flowing into the heat exchanger from the bathtub, and an outlet water temperature for measuring a temperature of the heated water returned to the bathtub. A recirculating bath kettle controller, which calculates a flow rate with a detector. 3. The circulation bathtub controller according to claim 1, wherein the flow rate measuring means calculates a flow rate from a rotation speed of the forced circulation device.