JPS61289265A - Flow amount control of hot-water supplier - Google Patents

Abstract

PURPOSE:To permit to prevent boiling and reduce overshoot by a method wherein the flow amount is reduced before starting the combustion of a combustion device while the flow amount is increased upon starting the combustion of the same. CONSTITUTION:A difference between the hot-water temperature at the outlet side of a heat exchanger 2, heated by the combustion device 1, and a set temperature is obtained while the flow amount of water, passing through the heat exchanger 2 is controlled in accordance with the difference. The flow amount is reduced before starting the combustion of the combustion device 1 while the flow amount is increased upon starting the combustion of the same device 1. According to this method, much amount of low-temperature hot-water is not discharged before starting the combustion of the combustion device 1, boiling immediately after starting the combustion of the same device 1 is eliminated, the overshoot of hot-water temperature may be reduced, and safe and stable hot-water supply may be effected. This method is the optimum especially for the hot-water supplier, in which the hot-water heated by the heat exchanger 2 is reserved once into a hot-water reserving tank.

Description

[Detailed Description of the Invention] (a) Industrial Application Field This invention calculates the deviation between the temperature of hot water at the outlet side of a heat exchanger heated by a combustion device and the set temperature, and adjusts the temperature of the heat exchanger according to this deviation. The present invention relates to a flow rate control method for a water heater that controls the flow rate passing through per unit time.

(B) Conventional technology The conventional method for controlling the flow rate of water heaters is to arrange a temperature centimeter at the outlet of a heat exchanger heated by a combustion device, and to determine the difference between the temperature detected by this temperature sensor and the desired set temperature. is determined, and the pump flow rate is adjusted according to this deviation to increase or decrease the flow rate passing through the heat exchanger per unit time, so that the hot water temperature at the outlet side of the heat exchanger approaches the set temperature.

The above-described method for controlling the flow rate of a water heater has the advantage that it can be constructed at low cost, such as by requiring only one temperature sensor to be provided at the outlet IC of the heat exchanger. However, immediately after the combustion equipment starts combustion, the temperature of the hot water at the exit side of the heat exchanger rises very quickly, so as shown in Figure 4, the pump flow rate cannot be controlled, causing problems such as boiling and large overshoots. there were.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 59-24317, the flow rate of the pump is increased more than usual when starting the water heater. However, with this method, a large amount of low-temperature water is released before the combustion equipment starts combustion.
In the case of a hot water storage type, there were drawbacks such as hot water being stirred within the hot water storage tank.

(c) Problems to be Solved by the Invention The problem of the present invention, which was made in view of the above-mentioned prior art, is to avoid discharging a large amount of low-temperature water before the start of combustion in the combustion device. This is to prevent boiling and large overshoots.

B) Means for Solving the Problems In order to solve the above problems, the flow rate control method for a water heater according to the present invention reduces the flow rate before the combustion device starts combustion, and increases the flow rate when the combustion device starts combustion. It is the composition.

(e) Effect With this configuration, the flow rate passing through the heat exchanger per unit time is small before the combustion apparatus starts combustion.

A large amount of low-temperature water is not dispensed. Then, when the combustion device starts combustion, the flow rate increases.

Therefore, the hot water temperature on the outlet side of the heat exchanger gradually increases. Moreover, hot water is quickly supplied to the outlet of the heat exchanger due to the increased pressure of the flow rate, eliminating delays in flow rate control and preventing boiling.

Overshoot becomes smaller.

(f) Example Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 shows an example of a water heater to which the present invention is applied. In Fig. 1, ill is a combustion device and seven gas burners, (2) are heat exchangers heated by gas burner ill, (3) are hot water storage tanks, (4) are water supply pipes, (5) are
(6) is a hot water supply pipe, and (6) is a heat exchanger (
(7) is a circulation pump installed in the water circuit (6) on the inlet side of the heat exchanger (21), (8) is the water circuit (6) on the outlet side of the heat exchanger (2). ) is a temperature sensor that detects the hot water temperature, (9) is a temperature setting device, and aα is a temperature sensor that compares the detected temperature of the temperature sensor (8) with the set temperature of the temperature setting device (9) to control the flow rate of the pump (7). It is a control device that performs this, and is equipped with a flame detector such as a flame rod aυ that detects the presence or absence of combustion flame of a burner (IJ).

FIG. 2 shows a specific circuit example of the control device αa.

In Fig. 2, (12Q31 is a bus connected to a power supply (not shown)), and between 121Q31 and 121Q31 a temperature setter (9) consisting of a variable resistor and a temperature sensor ( 8) and are the respective resistances (14) QS
connected via. (ll19 calculates the deviation between the detected temperature of the temperature sensor (8) and the set temperature of the temperature setting device (9) from the voltage of these connection points Q71 (18), and sets the hot water temperature on the outlet side of the heat exchanger (2). It is an arithmetic circuit that emits an output voltage V at the output terminal (16P) according to the deviation between the two temperatures as the temperature approaches (as in α9C1
! [) is the arithmetic circuit (IQ output terminal (16P) and bus line αJ
The resistor (211) is connected in series between the resistor (19
A normally open relay switch connected in parallel with , ■ is a resistor (1
9 (Flow rate control circuit that inputs the voltage V at the connection point of 2G as a flow signal and controls the flow rate by adjusting the rotation speed of the pump (7), for example, between the r24Jt frame rod αυ and the ground (c) The ignition detection circuit turns on the transistor (2) when it detects a flowing current, and +211 is an auxiliary relay for driving the relay switch (211) connected between the busbars (121 (131)) through the transistor [Co., Ltd.].

The operation of the above embodiment will be explained with reference to FIG.

Now, assuming that the gas burner il+ has pre-purged and is not burning, the output voltage v0 of the arithmetic circuit αe is divided by the resistor asanc, and the voltage V at the connection point is supplied to the flow rate control circuit Ω as a flow rate signal. ing. At this time, the pump flow rate is small, and the flow rate passing through the heat exchanger (2) per unit time is small.

Therefore, the water at the bottom of the hot water storage tank (3) flows into the water circuit (6).
The agitation of the hot water caused by the hot water being returned to the upper part of the hot water storage tank (3) via the hot water storage tank (3) is suppressed to a minimum.

When the blip purge is completed and the gas burner + IJK is ignited,
Ignition detection circuit Q4 is connected to frame rod QD ground (c)
The current flowing between them is detected and transistor (2) is made conductive. Then, the auxiliary relay is energized and the relay switch (
211) is closed. At this time, the resistor α9 is short-circuited by the relay switch (211), and the output voltage Vo of the arithmetic circuit (161) becomes the input voltage V1 of the flow rate control circuit (■), so the pump flow rate increases rapidly as shown in Figure 3. In this way, when the pump flow rate is rapidly increased at the same time that the gas burner (II) starts combustion, the hot water temperature on the outlet side of the heat exchanger (2) gradually increases.

Furthermore, as the flow rate increases, the temperature sensor (8) quickly detects a rise in the hot water temperature, so the arithmetic circuit αe gradually lowers the output voltage v0 and reduces the pump flow rate.

As a result, the hot water temperature gradually approaches the set temperature,
Boiling and large overshoots are prevented.

Furthermore, when the hot water temperature reaches the set temperature, the pump flow rate also stabilizes.

After that, when a deviation occurs between the temperature detected by the temperature sensor (8) and the set temperature due to changes in the water supply temperature or the water temperature in the hot water storage tank (3), the arithmetic circuit αe changes the output voltage in the direction where the deviation disappears again. Increase or decrease v0 and readjust the pump flow rate (flow rate passing through the heat exchanger (2) per unit time). Therefore, hot water maintained at approximately the set temperature is stored in the hot water storage tank (3) in order from the top. And hot water storage tank (3
) is sent from the hot water supply pipe (5) to the usage area as needed.

Moreover, when hot water is dispensed, water is supplied from the water supply pipe (4) to the hot water storage tank (3) accordingly.

According to this embodiment, before the start of combustion in the gas burner +17, the output voltage v0 of the arithmetic circuit ubl is divided by the resistor UBL.

The flow rate control circuit (2
), the pump flow rate is reduced, and agitation of hot water at the upper part of the hot water storage tank (3) can be suppressed. Also, when the gas burner (1) starts combustion, the resistor a9 is short-circuited with the relay switch (211), and the arithmetic circuit (161) is short-circuited.
Since the output voltage v0 of is summed so as to be supplied as is to the flow rate control circuit ■, the flow rate passing through the heat exchanger (2) per unit time increases rapidly, and the hot water temperature on the outlet side of the heat exchanger (2) gradually decreases. can be raised to Therefore, control errors immediately after the start of combustion in the gas burner (1) are eliminated, stable flow control is performed, and the hot water temperature can be quickly brought close to the set temperature. Shoots can be prevented.

In the above-described embodiment, the ignition detection circuit (incorporated) generates an ignition output and increases the flow rate when the transistor (11) is made conductive. They may be summed to increase the flow rate.

(G) Effects of the Invention As explained above, the present invention calculates the deviation between the temperature of the hot water at the outlet side of the heat exchanger heated by the combustion device and the set temperature.
In a water heater flow rate control method that controls the flow rate passing through a heat exchanger per unit time according to this deviation, the flow rate is decreased before the combustion device starts combustion, and the flow rate is increased when the combustion device starts combustion. As a result, without having to pour out a large amount of low-temperature water before the combustion equipment starts combustion, it is possible to eliminate boiling immediately after the combustion equipment starts combustion, and to reduce hot water temperature overshoot, resulting in safe and stable hot water supply. It is particularly suitable for water heaters that temporarily store hot water heated by a heat exchanger in a hot water storage tank.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a water heater to which the present invention is applied, and FIG. 2 is an electric circuit diagram showing an example of the present invention.
FIG. 3 is an explanatory diagram for explaining the operation of an embodiment of the present invention, and FIG. 4 is an explanatory diagram for explaining the operation of the conventional method. (II... Gas burner (combustion device), (2)...
Heat exchanger. (8)...Temperature sensor, (9)...Temperature setting device,
aω...control device. Applicant Sanyo Electric Co., Ltd. and 1 other representative Patent attorney Masao Sano 10: / Mo 7 Figure 3 Figure 4 Figure 4 Ku Haruma

Claims (1)

[Claims] (1) A flow rate control method for a water heater that calculates the deviation between the hot water temperature at the exit side of the heat exchanger heated by the combustion device and the set temperature, and controls the flow rate passing through the heat exchanger per unit time according to this deviation. A flow rate control method for a water heater, characterized in that the flow rate is reduced before the combustion device starts combustion, and the flow rate is increased when the combustion device starts combustion.