JP2010054062A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater capable of positively selecting a thermistor with proper fast responsiveness for the temperature control of the water heater when using a temperature sensor having two thermistors incorporated in one protection tube. <P>SOLUTION: The water heater 1 includes a selecting means 8 for selecting and setting one thermistor for temperature control of two thermistors 71, 72 incorporated in the temperature sensor 7. The selecting means 8 temporarily determines (S5) one of the two thermistors 71, 72 for temperature control when water is passed through a water circuit 3 with respect to the temperature sensor 7. Then, when a heating means 20 of the water heater 1 is started and a water temperature in the water circuit 3 rises, the thermistor 71 with higher detection temperatures is officially set for temperature control (S6-S8). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus in which a temperature sensor in which two thermistors are incorporated in one protective cylinder is attached to a water circuit.

Conventionally, in a hot water supply device, for example, two thermistors are incorporated in one protective cylinder as a temperature sensor for detecting a tapping temperature, one of the thermistors is used for temperature control, and the other is used for monitoring or preventing overheating. May be used. In this case, when determining the role of each thermistor, the temperature sensor is placed in a thermostatic bath before being attached to the water circuit of the hot water supply device, and the thermistor having the shorter response time, that is, the faster thermistor is reached. There was a method of presetting for temperature control (Patent Document 1).
JP-A-60-73324 JP 2000-241259 A

  However, the environment for the temperature sensor is different between the constant temperature bath where there is no hot water flow and the water circuit of the hot water supply device where the hot water flows. Therefore, the responsiveness of each thermistor when the temperature sensor is mounted in the water circuit may be different from that measured when the temperature sensor is immersed in a thermostatic bath. Even in the water circuit, the responsiveness to the temperature of each thermistor may change depending on the mounting state of the temperature sensor. For example, it is conceivable that the thermistor located upstream of the hot water flow will quickly follow the water temperature and respond faster. Therefore, if the thermistor for temperature control is fixedly set before attaching the temperature sensor to the water circuit, the thermistor with the slower response may actually be used for temperature control when the hot water supply device is used. It was. If it does so, quick temperature control will become difficult with a hot-water supply apparatus.

  The present invention has been made in view of the above circumstances, and in the case of using the above temperature sensor, provides a hot water supply device that can reliably select a thermistor having a quicker response suitable for temperature control of the hot water supply device for temperature control. The task is to do.

The hot water supply apparatus according to the present invention is
A hot water supply device in which a temperature sensor incorporating two thermistors in one protective cylinder is attached in a water circuit,
When the temperature sensor is passed through the water circuit, one of the two thermistors is temporarily determined to be used for temperature control, and then the heating means of the hot water supply device is started and the water temperature in the water circuit is rising. This is provided with sorting means for officially setting the thermistor having a higher detected temperature at the time for temperature control.

From the above configuration, first, when the temperature control thermistor is provisionally determined when water is passed through the water circuit, the temperature control when the heating means is started can be performed.
Next, when the heating means of the water heater is started and the water temperature in the water circuit is rising, the thermistor having the higher detected temperature is formally set for temperature control. This is because when the heating means is started and the water temperature in the water circuit is stabilized by temperature control, the detected temperatures of the two thermistors become substantially equal, but in the transient state during the rise of the water temperature, there is a difference in the detected temperature of each thermistor. Occurs. This is considered to be caused by a difference in heat conduction from hot water flowing to each thermistor in the protective cylinder depending on the temperature sensor attached to the water circuit. And it can be said that the detected temperature is high because the response of the thermistor is quicker when the detected temperature is high in the transient state while the water temperature is rising. Therefore, the thermistor having the higher detection temperature at the time when the water temperature is rising is formally used for temperature control, so that the thermistor having the faster response can be used for temperature control after starting the heating means.
From the above, it is possible to reliably identify the thermistor having the faster response regardless of the state of the temperature sensor attached to the water circuit, and as a result, the temperature is quickly adjusted based on the detected temperature from the thermistor. be able to.

The sorting means may be configured so that the thermistor having a higher detected temperature is used for temperature control when the water is passed through the water circuit as the provisional decision.
Thereby, even when each thermistor is passed through the water circuit, the detected temperature is indicated according to the difference in heat conduction from the flowing water. Therefore, even when provisional determination is made, the thermistor having the higher detected temperature is used for temperature control as described above, so that the thermistor having the faster response can be used for temperature control when starting the heating means.

The screening means is configured to select and set the temperature control thermistor when the hot water supply is started for the first time after the main power supply of the water heater is turned on.
The configuration of the temperature control thermistor may be reset when the main power supply of the water heater is turned off.
As a result, when the hot water supply is started for the first time after the main power supply of the hot water supply device is turned on, the previously heated water does not circulate in the water circuit. I can capture it reliably. Therefore, the thermistor with the faster response can be reliably identified.
Also, when the main power supply of the hot water supply device is turned off, the setting of each thermistor is reset, so even if the main power supply of the hot water supply device is turned off and the temperature sensor is replaced for maintenance, etc. Then, the thermistor that responds faster when the main power supply of the hot water supply device is turned on next time can be reliably identified and set.

The selecting means may be configured to select and set the temperature control thermistor every time a cold start is started to start hot water supply in a state where the water temperature in the water circuit is lowered.
As a result, hot water that has been warmed before does not circulate in the water circuit during a cold start, so it is possible to reliably detect the transient state during the rise in water temperature and to identify the thermistor with the faster response. can do. By performing the above setting at each cold start, the thermistor with the faster response can be reliably identified even if there is a change in the situation such as the temperature sensor mounting state being changed due to aging.

As the temperature sensor, one in which two thermistors having the same resistance value are arranged side by side in a cylindrical protective cylinder can be used.
If two thermistors having the same resistance value are arranged side by side, for example, the thermistor located upstream of the hot water flow in the water circuit is first thermally conducted from the hot water and quickly reaches the water temperature. It is thought that the response will be quicker following. However, if the protective cylinder is cylindrical, the position relationship of each thermistor varies with respect to the direction of rotation depending on the state of attachment of the temperature sensor to the water circuit, and it is possible to identify an upstream thermistor that is considered to respond quickly. Have difficulty.
Even with such a temperature sensor, as described above, the thermistor with the faster response can be reliably identified by the selecting means regardless of the state of attachment of the temperature sensor to the water circuit.

  As described above, according to the present invention, regardless of the temperature sensor attached to the water circuit, the thermistor with the faster response can be reliably set and the temperature can be quickly adjusted. Therefore, the hot water supply apparatus excellent in the temperature control performance which can stabilize the temperature of hot water quickly to preset temperature is provided.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A hot water supply apparatus 1 according to the embodiment shown in FIG. 1 includes a heat exchanger 31 heated by a gas burner (heating means) 20, and a water supply pipe 32 and a hot water discharge pipe 33 connected to the heat exchanger 31. Water circuit 3 is formed in which water supplied to 32 is heated by heat exchanger 31 to discharge hot water from a hot water outlet of hot water discharge pipe 33. The hot water supply device 1 is connected to the hot water supply control unit 4 for temperature control so that the hot water temperature at the hot water supply port becomes a predetermined hot water supply temperature, and is connected to the hot water supply control unit 4 to input the set temperature of the hot water. Remote control 5 for the purpose. The water supply pipe 32 is provided with a water amount sensor 6 for detecting the presence / absence of water flow through the water supply pipe 32 and the amount of water flow, and the hot water discharge pipe 33 detects the temperature of hot water supplied to the hot water discharge pipe 33. A temperature sensor 7 as a temperature sensor is provided. In FIG. 1, reference numeral 21 denotes a fan. The fan 21 sends combustion exhaust from the gas burner 20 to the heat exchanger 31 to heat the heat exchanger 31.

  As shown in FIG. 2, the temperature sensor 7 includes two thermistors 71 and 72 arranged side by side in a cylindrical protective cylinder 70 in the vicinity of the tip of the protective cylinder 70. The protective cylinder 70 is formed of a metal material having high thermal conductivity (for example, stainless steel). The protective cylinder 70 is filled with a highly heat-conductive filler 73 (for example, epoxy resin), and the thermistors 71 and 72 are fixed in a non-contact state with the inner peripheral surface of the protective cylinder 70. . Further, the thermistors 71 and 72 are held so that the distance from the inner peripheral surface of the protective cylinder 70 is substantially the same. Thereby, heat from the outer periphery is transmitted evenly from the surface of the protective cylinder 70 to the thermistors 71 and 72 via the filler 73.

  As each thermistor 71, 72, an NTC (Negative Temperature Coefficient) type in which the resistance decreases with respect to the temperature rise is used, but a PTC (Positive Temperature Coefficient) type in which the resistance increases with respect to the temperature rise can also be used. . The thermistors 71 and 72 having the same resistance value are used, and the detected temperature characteristics of the thermistors 71 and 72 themselves are substantially the same.

  As described above, the thermistors 71 and 72 included in the temperature sensor 7 have the same resistance value, but the responsiveness to the temperature of the thermistors 71 and 72 varies depending on the mounting state of the temperature sensor 7 in the tapping pipe 33. Sometimes. For example, when the two thermistors 71 and 72 are arranged side by side as described above, the thermistor 71 (see FIG. 2) located on the upstream side with respect to the flow of hot water in the tapping pipe 33 is first. Heat is transferred from the hot water and quickly follows the water temperature, and as a result, the response is considered to be faster. In this case, it is advantageous for temperature control of the hot water supply apparatus 1 to use the thermistor 71 located on the upstream side for temperature control. However, since the protective cylinder 70 is formed in a cylindrical shape so that it can be sealed with the hot water pipe 33 by the O-ring 74, there are various positional relationships between the thermistors 71 and 72 with respect to the rotation direction of the protective cylinder 70. Thus, it is difficult to specify the upstream thermistor 71 that is considered to respond quickly.

  Therefore, in the hot water supply device 1, either of the two thermistors 71 and 72 included in the temperature sensor 7 is used as a temperature control thermistor with respect to the temperature sensor 7 attached to the outlet pipe 33. Sorting means 8 for sorting and setting these is provided. The sorting unit 8 includes a memory 81 for storing which thermistors 71 and 72 are set for temperature control (see FIG. 1).

The operation for selecting and setting the temperature control thermistor by the selecting means 8 will be described below.
With reference to the flowchart of FIG. 3, after the main power supply of the hot water supply device 1 is turned on (S1), the hot water tap is first opened (S2) and the water amount sensor 6 detects water flow (S3), the sorting means 8 is Then, it is confirmed whether or not the temperature control thermistor is set among the two thermistors 71 and 72 of the temperature sensor 7 (S4). When the temperature control thermistor is not set, when the water amount sensor 6 detects water flow in the water supply pipe 32, the sorting means 8 temporarily determines the thermistor 71 having a higher detection temperature for temperature control. (S5). Thereby, the temperature control when the gas burner 20 is ignited can be performed by the hot water supply control unit 4 based on the detected temperature of the temperature control thermistor 71 tentatively determined.

  Next, when the amount of water detected by the water amount sensor 6 is equal to or greater than the minimum working water amount (for example, 3 liters / minute) and the gas burner 20 is ignited (S6), the sorting means 8 is set to α time after the gas burner 20 is ignited. At a later time (S7), the thermistor 71 having a higher detected temperature is formally set for temperature control and stored in the memory 81 (S8).

  Here, the time point after the α time is an arbitrary time point in the transient state during the rise of the water temperature, and is arbitrarily set by the hot water supply device 1, for example, any time until 5 seconds elapse after the gas burner 20 is ignited. The time can be set. As shown in the graph of FIG. 4, when the gas burner 20 is ignited and the water temperature in the tapping pipe 33 is stabilized by temperature control, the detected temperatures of the two thermistors 71 and 72 of the temperature sensor 7 are substantially equal. (Refer to “Tempered water temperature” in FIG. 4) In the transient state during the water temperature rise, there is a difference in the detected temperature of each thermistor 71, 72 (see “Transient state” in FIG. 4). . This is considered to be caused by a difference in heat transfer from the hot water flowing to the thermistors 71 and 72 in the protective cylinder 70 depending on the state of the temperature sensor 7 attached to the hot water discharge pipe 33. And it can be said that the detected temperature is high because the thermistor 71 has a quick response when the detected temperature is high in a transient state during the rise of the water temperature. Therefore, as described above, by using the thermistor 71 having a higher detected temperature (for example, the thermistor located on the upstream side) for the temperature control at the time point α after the ignition of the gas burner 20, the faster response is achieved. The thermistor 71 can be reliably specified and used for temperature control.

  With reference to FIG. 3, thereafter, until the hot water tap is closed, the remote controller 5 sets the temperature control thermistor 71 based on the detected temperature of the temperature control thermistor 71 set and stored for temperature control here. The temperature is controlled so that the hot water having the set temperature is discharged (S9, S10). Until the main power supply of the hot water supply device 1 is turned off (S11), based on the temperature detected by the temperature control thermistor 71 set by the sorting means 8, the set temperature set by the remote control 5 by the hot water supply control unit 4 The temperature is controlled so that no hot water is discharged (S2 to S4, S9 to S11). The other thermistor 72 is set by the sorting means 8 so as to be used for monitoring the set temperature control thermistor 71 and stored in the memory 81. When the temperature difference between the detected temperature of the monitoring thermistor 72 and the detected temperature of the temperature control thermistor 71 exceeds a predetermined temperature (for example, 5 ° C.) by a failure determination means (not shown), the monitoring thermistor 72 is disconnected. Is used to determine that the temperature sensor 7 has failed.

  Thereafter, when the main power supply of the hot water supply apparatus 1 is turned off for maintenance or the like (“Yes” in S11), the above settings of the thermistors 71 and 72 by the selection means 8 are erased from the memory 81 and reset (S12). Then, when the main power supply of the hot water supply device 1 is turned on next time (S1), the selecting means 8 selects one of the two thermistors 71 and 72 provided in the temperature sensor 7 as described above as a temperature control thermistor. And set as (S2 to S8). Thereby, even when the main power supply of the hot water supply apparatus 1 is turned on next time, even when the main power supply of the hot water supply apparatus 1 is turned off and the temperature sensor 7 is replaced and the mounting state of the hot water discharge pipe 33 is changed. The thermistor 71 having a faster response to the temperature sensor 7 attached to the hot water discharge pipe 33 can be reliably identified and set.

  In addition, when hot water supply is started for the first time after the main power supply of the hot water supply device 1 is turned on, the previously heated hot water does not circulate in the water circuit 3, so that the transient state during the rise of the water temperature described above (See FIG. 4) can be reliably captured. Therefore, the thermistor 71 having a faster response can be reliably identified.

  As described above, according to the hot water supply device 1 according to the present embodiment, the thermistor 71 having the quicker response is surely identified and the temperature can be quickly adjusted regardless of the state of the temperature sensor 7 attached to the outlet pipe 33. be able to. Therefore, the hot water supply apparatus 1 excellent in temperature control performance that can quickly stabilize the temperature of hot water at the set temperature is provided.

In addition, this invention is not limited only to the said embodiment, It can change within the scope of the present invention.
For example, the selection means 8 sets the thermistors 71 and 72 of the temperature sensor 7 only during the first operation after the main power supply of the hot water supply device 1 is turned on, but the water temperature in the water circuit 3 decreases. The thermistors 71 and 72 may be set each time a cold start is started in which hot water supply is started. The cold start determination is made when, for example, a predetermined time (a time during which the water temperature in the water circuit 3 decreases to approximately the water supply temperature) has passed since the end of the previous hot water supply operation when starting the hot water supply. It may be judged as a start. As a result, since the hot water previously heated does not circulate in the water circuit 3 at the cold start, the transient state during the rise of the water temperature is surely captured, and the thermistor 71 having a quick response is surely detected. Can be specified. By performing the above setting at each cold start, it is possible to reliably identify the thermistor 71 having a quicker response even if there is a change in the situation such as a change in the mounting state of the temperature sensor 7 over time. .

  Further, in the sorting means 8, the time point after the time α is compared to the time point at which the detected temperatures of the thermistors 71 and 72 are compared, and the thermistor 71 whose detected temperature is continuously higher than two times is determined as the temperature. It may be set for control. As a result, the thermistor 71 having a faster response can be identified more reliably.

  Further, in the sorting means 8, the time points after the time α are set as a plurality of time points, and the temperature gradients of the detected temperatures of the thermistors 71 and 72 are also acquired, and the detected temperature is higher and the gradient of the temperature gradient is larger. The thermistor 71 is set and stored for temperature control until the main power supply of the hot water supply device 1 is turned off, and is the thermistor 71 having a higher detected temperature, but the inclination of the temperature gradient is smaller. May be set for temperature control until the next cold start, and the temperature control thermistor may be selected based on the detected temperature and the temperature gradient again at the next cold start. As a result, the thermistor 71 having a faster response can be identified more reliably.

  Moreover, although the said embodiment showed the case where it was set as the hot water temperature sensor which detects the hot water temperature attached to the hot water pipe 33 of the hot water supply apparatus 1 as the said temperature sensor 7, this invention is not limited to this, The bath circulation circuit It can be applied when used as various temperature sensors such as a bath temperature sensor for detecting the bath temperature by attaching to a hot water pipe, and a temperature sensor for detecting the temperature of the hot water by attaching to a hot water pipe of a hot water type floor heating.

It is the block diagram which showed the whole structure of the hot water supply apparatus by embodiment. It is sectional drawing which showed the attachment state of the temperature sensor to the tap pipe in a hot water supply apparatus. It is the flowchart which showed the operation | movement which selects the temperature control thermistor. It is the graph which showed the change of each detection temperature of two thermistors at the time of the transient state during water temperature rise.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot-water supply apparatus 3 Water circuit 4 Hot-water supply control part 6 Water quantity sensor 7 Temperature sensor 8 Sorting means 20 Gas burner (heating means)
31 Heat exchanger 32 Water supply pipe 33 Hot water pipe 70 Protection cylinder 71, 72 Thermistor

Claims (5)

A hot water supply device in which a temperature sensor incorporating two thermistors in one protective cylinder is attached in a water circuit,
When the temperature sensor is passed through the water circuit, one of the two thermistors is temporarily determined to be used for temperature control, and then the heating means of the hot water supply device is started and the water temperature in the water circuit is rising. A hot water supply apparatus equipped with a screening means for officially setting the thermistor with the higher detected temperature at the time for temperature control. The hot water supply apparatus according to claim 1,
A hot water supply apparatus in which the selecting means uses a thermistor having a higher detected temperature for temperature control when water is passed through the water circuit as the provisional decision. The hot water supply apparatus according to claim 1 or 2,
The screening means is configured to select and set the temperature control thermistor when the hot water supply is started for the first time after the main power supply of the water heater is turned on.
A hot water supply apparatus configured to reset the setting of the thermistor for temperature control when the main power supply of the hot water supply apparatus is turned off. The hot water supply apparatus according to any one of claims 1 to 3,
The hot water supply apparatus configured to select and set a temperature control thermistor each time a cold start is started when hot water supply is started in a state where the water temperature in the water circuit is lowered. The hot water supply apparatus according to any one of claims 1 to 4,
The temperature sensor is a hot water supply device in which two thermistors having the same resistance value are arranged side by side in a cylindrical protective cylinder.

Images