JPS60207852A - Feed water temperature detecting device in hot water storage type electric heater - Google Patents

Abstract

PURPOSE:To accurately control the heating by utilizing midnight power by a method wherein the minimum feed water temperature in a day is obtained by periodically bringing the feed water temperature in a hot water storage tank during the time when a heat generating body for midnight power is OFF. CONSTITUTION:When a midnight power heater 3 is turned OFF, a first comparator unit 10 brings the water temperature detected by a temperature sensor 7 in the cycle of mili-second order in order to obtain the minimum temperature in a day. A memory unit 11 stores the minimum temperatures obtained at the comparator unit 10 for the predetermined number of days and has memory areas M1-Mn corresponding to the predetermined number of days (n). A second comparator unit 12 brings the minimum values stored respectively in the memory areas M1-Mn in order to obtain the minimum value among the respective minimum values. An operational processing unit 13 calculates in order to obtain the operating hour of a midnight power heater 3 necessary for heating the water in a hot water storage tank 3 up to the required heating-up temperature under the condition that the minimum value obtained at the comparator 12 is employed as the feed water temperature. In addition, the energizing of the midnight power heater 3 is controlled through a relay 14 by the control signal corresponding to the result of the calculated operating hour of the heater 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a water supply temperature detection device for detecting the temperature of water supplied to a hot water storage tank in a hot water storage type electric water heater that utilizes late-night electricity.

(Prior art) Normally, in this type of electric water heater, as shown in Fig. 6, tap water supplied through a water supply pipe into a hot water storage tank a is heated to a predetermined temperature by a late-night power heater d during the night. The bathroom was raised and the hot water pipe was empty.

It is designed to be supplied to various places such as bathrooms.

By the way, the temperature of the tap water, that is, the temperature of the water supply, is influenced by the air temperature and varies depending on the season or day. Therefore, the temperature of the water supply is detected by the temperature detection means e, and the amount of heat required by the user is determined according to the detection result. The system is designed to control the boiling up to the required discharge temperature commensurate with the temperature. and.

As shown in FIG. 6, the detection position of the water supply water temperature, that is, the installation position of the temperature detection means e, may be either in the water supply pipe or in the hot water storage tank a.

However, in the former case, it is necessary to newly install a temperature sensor or the like to the water supply pipe, which poses a construction problem. In the latter case, there are no construction problems as in the former case, but on the other hand, since the temperature detection means e is provided inside the hot water storage tank a, there is a problem that it is difficult to detect the true water supply water temperature. there were.

In particular, 5 one temperature detection means e provided above the heater d.
However, in the case where both the hot water temperature and the water supply temperature are detected, there is a problem in that the temperature of the water supply cannot be accurately detected due to the influence of the heater d.

In addition, even in electric water heaters that use late-night power as mentioned above, in order to downsize the hot water storage tank a, daytime power (100
There is a structure in which a heater (f) for electric power (voltage) is added to compensate for the insufficient amount of heat even during the daytime. In such a structure, since convection occurs within the hot water storage tank a, a temperature-based separation layer between the hot water layer and the water layer is not formed. Therefore, it is not enough to just capture the water supply temperature at a point in time before the power is turned on in the middle of the night.

The value was higher than the true water supply temperature, making the calculation light inaccurate and lacking in reliability.

(Objective of the Invention) The present invention has been made in view of such conventional problems, and an object of the present invention is to significantly improve the accuracy of detecting the temperature of supplied water even though the temperature detecting means is incorporated in the hot water storage tank. It is an object of the present invention to provide a water supply temperature detection device for a hot water storage type electric water heater that can perform boiling control using late-night electric power with extremely high accuracy.

(Structure of the Invention) As shown in FIG. A power heating element is taken in periodically during leaf F to determine the minimum temperature of the day. The determined minimum temperature is stored by the storage means j for a predetermined number of days. The lowest value among these stored lowest temperatures is determined by the second comparing means k.

(Example) Two embodiments of the present invention will be described below with reference to the drawings.

An electric water heater equipped with a water supply temperature detection device according to the present invention is shown in FIG. Heater for late-night electricity (200 volt heater)
3 is provided, and the operation of the late-night power heater 3 is controlled by a water supply temperature detection device 4. In addition, 5 is a water supply pipe that supplies tap water into the hot water storage tank 2, and is connected to the partition part of the bottom 2b of the hot water storage tank 2. Also, 6 is a water supply pipe that supplies tap water into the hot water storage tank 2, and 6 is a water supply pipe that supplies tap water to the hot water storage tank 2. Supply IA that supplies hot water to various water heaters (not shown)! The hot water tank 2 is connected to the center of the top 2C of the hot water storage tank 2. When the user uses hot water from the water heater, the hot water heated by the late-night power heater 3 in the hot water storage tank 2 is transferred to the hot water pipe 6.
Hot water is supplied through the hot water tank 2, and tap water is supplied into the hot water storage tank 2 through the water supply pipe 5. Therefore, in the hot water storage tank 2, there is a layer of hot water boiled up in the soil part 2d.

Water layers are formed in the lower part 2a, and temperature-based separation layers are formed.

Next, the details of the structure of the feed water temperature detecting device 4 are shown in FIG. 3, and the feed water temperature detecting device 4 includes a temperature sensor 7, a microcomputer 8, and the like.

As shown in FIG. Mouth portion 5a of water supply pipe 5 at the bottom of tank 2
It is provided near the top of the heater 3. The temperature sensor 7 detects the water temperature and IA temperature near the opening 5a,
The detection result is sent to the microcomputer 8 as a digital signal. Note that as the temperature sensor 7, one with a small time constant that can immediately respond to one ambient temperature is used.

The microcomputer 8 is used to process the above detection results and control the operation of the late-night power heater 3.
/D converter 9. First comparison section 10° storage section 11. It is composed of a second comparison section 12 and an arithmetic processing section 13. A/
The D converter 9 converts an analog quantity into a digital quantity, and converts the voltage signal (analog quantity) from the temperature sensor 7 into a digital quantity and sends it to the first comparison part IO.

The first comparator 10 measures the lowest water temperature of the day detected by the temperature sensor 7, and compares the detection result from the temperature sensor 7 with A during the period when the late-night power heater 3 is off.
/D converter 9 and calculate the lowest value.

The storage section 11 stores the minimum temperature determined by the first comparison section 10 for a predetermined number of days, and has storage areas M1 to Mn corresponding to the predetermined number of days r). The predetermined number of days n is set to the maximum number of days in which the hot water (or water) in the hot water storage tank 2 can be used without replacing for sanitary reasons, and is set to 5, for example, n=4 to 7.

The second comparing section 12 calculates the lowest value among the lowest temperatures stored in the storage section 11, and takes in each of the lowest values stored in the storage areas M1 to Mn and calculates the lowest value.

The arithmetic processing section 13 performs arithmetic processing on the minimum value determined by the second comparison section 12 to control the operating time of the late-night power heater 3. Based on this data, the operating time of the late-night power heater 3 required to boil the water in the hot water storage tank 3 to the required temperature is calculated by tJ as the water supply temperature. Then, energization of the late-night power heater 3 is controlled via the relay 14 using a control signal corresponding to this calculation result.

Next, the operation of the feed water temperature detection device 4 will be explained according to the flowcharts of FIGS. 4 and 5.

When the late-night power heater 3 reaches temperature F, the first comparator 10 sequentially takes in the water temperature detected by the temperature sensor 7 at millisecond intervals, and calculates the lowest temperature of the day according to the procedure shown in FIG. That is, in FIG.

Obtain the water temperature in step ■. In step ■, it is determined whether or not this captured temperature is lower than the temperature stored in the old NM register. Replace the data with a new Regisf old NVI hesent. Then, return to step ■ again. on the other hand.

In step (2), if the captured temperature is not lower than the temperature of the old register NM, the process returns to step (2).

On the other hand, the second comparison section 12 takes in the lowest temperature stored in the storage section 11, and calculates the lowest value according to the procedure shown in FIG. That is, in FIG.

In step (2), the lowest temperatures stored in the storage areas M1 to Mn of the storage unit 11 are sequentially shifted and stored from M1 to M2, M2 to M3, . . . from Mn-1 to Mn, and Mn The oldest minimum temperature stored in is erased. Then, use the Ste knob ■ to select the above register MIN.
The temperature of M is set as the lowest temperature of the day and is calculated by 1 degree between storage areas.

Next, in step (2), the second comparison unit 12
Take the lowest temperature stored in l-Mn and find the lowest value among the lowest temperatures.

The calculation processing unit 1 uses the lowest value as data of the water supply water temperature.
Send to step 3 (step ■). Then, the calculation processing unit 13 calculates the energization time of the late-night power heater 3 based on this data.

In addition, although the above-mentioned embodiment is a case where only the late-night power heater 3 is provided, it is also applicable to a case where a daytime power heater 16 (see FIG. 2) is also provided. That is, when the daytime power heater 16 is energized as necessary during the daytime hours, convection occurs in the hot water storage tank 2, and separation layers according to temperature are not formed as in the above embodiment. For this reason.

During daytime power supply heater 16 is energized, temperature sensor 7 detects a temperature higher than the true water supply temperature.

However, since the first comparison unit 10 always takes in the water supply temperature detected by the temperature sensor 7 at a short cycle of milliseconds during the daytime, that is, during the daytime, the first comparison unit 10 receives the water supply temperature detected by the temperature sensor 7 at all times, so that Accurate water supply temperature can be detected without being affected by the heater 16.

In addition, in the above embodiment, as shown in FIG.
The lowest value of the temperature taken periodically is left in the old register 11M, so it is convenient for the user.

Even if you don't know when to use hot water, you can accurately measure the water temperature.

Furthermore, even if the user does not use the hot water in the hot water storage tank 2 for a whole day, the data (minimum temperature) for day 0 is stored in the storage areas old to Mn of the storage unit 11, and the lowest value is Since this can be detected by the process shown in FIG. 5, there is no problem in practice.

(Effects of the Invention) As described in detail above, the present invention has a structure in which a temperature detection means is built into the hot water storage tank, but it is possible to greatly improve the detection accuracy of the water supply water temperature, and also to be able to avoid the influence of the heating element. It is possible to measure the water supply temperature even if the water temperature in the hot water storage tank changes from moment to moment. In addition, it is easy to install and highly reliable when installing a temperature detection means, and can be used in all situations, such as when an electric heater is used during the day, when hot water is used at irregular times, or when hot water is not used all day. Under these conditions, the operation of the late-night power heater can be controlled with extremely high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a water supply temperature detection device in a hot water storage type electric water heater of the present invention, and Figs. 2 to 5 illustrate embodiments of the present invention. 3 is a block diagram showing the outline of the configuration of the feed water temperature detection device in the water heater, FIG. 4 is a flowchart showing the operation of the device when the heater for late-night electricity is turned off, FIG. 5 is a flowchart showing the operation of the device when the late-night power heater is turned on, and FIG. 6 is a diagram corresponding to FIG. 2 of a conventional hot water storage type water heater. h...Temperature detection means i...First comparison means j...
Storage means k...Second detection means 2...Hot water storage tank
3... Heater for late night electricity 4... Water supply water temperature detection device
5... Water supply pipe 5a... Mouth part 6... Water supply pipe applicant Representative of Sekisui Chemical Co., Ltd. Shainuma Profiteering Figure 2 Figure 3 Figure 4 Figure 6 Figure 5

Claims (1)

[Claims] (1) For hot water storage type electric water heaters that use late-night electricity. Temperature detection means for detecting the water temperature in the hot water storage tank. the temperature detected by the temperature detection means. Periodically taken in while the heating element for late-night electricity is off. and a first comparison means to calculate the lowest temperature of 10. and storage means for storing the minimum temperature determined by the first comparison means for a predetermined number of days. A water supply temperature detecting device for a hot water storage type electric water heater, characterized in that it comprises second comparing means for calculating the lowest value among the lowest temperatures stored by the storing means.