JPS63197848A - Control method for mixing servo valve - Google Patents

Abstract

PURPOSE:To improve hot water feed characteristics during the re-feed of hot water and to rapidly stabilize feed hot water temperature, by a method wherein the motion of a mixing servo valve is kept stopped until, during re-feed of hot water, a feed hot water temperature is increased to a set value. CONSTITUTION:When, during the re-feed of hot water, there is no change in a set temperature in the case of hot start, the motion to the feed water closing side of a mixing servo valve 3 is kept stopped until a feed hot water temperature is increased to a set temperature. This constitution enables reduction of overshoot occasioned by a motion to the feed water closing side at the initial stage, permits improvement of hot water feed characteristics, and allows stabilization of a feed hot water temperature to a set value in a relatively short time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of controlling a mixing servo valve,
In particular, the present invention relates to a method of controlling a mixing servo valve that can improve the hot water dispensing characteristics during re-dispensing.

[Prior art]

For example, as shown in Figure 3, a mixing servo valve (
3, water enters the heat exchanger (1) side and the cold water passage (2) i[
l! By controlling the distribution ratio to both sides, the hot water temperature detected by the hot water temperature detector (4) is adjusted to the set temperature set by the setting device (6). Controlled to match. Conventionally, as shown in FIG. 4, for example, the mixing servo valve (3) has been operated (Sll) or stopped by determining whether or not the tapped water temperature is equal to the set temperature (S10). (812). (5) is a controller containing a microcomputer, etc. (6) is a water amount detector, and (7) is an inlet water temperature detector.

[Problem that the invention seeks to solve]

In such a conventional control method, as shown in FIG.
When hot water is re-discharged, the cold water cooled during pre-purge passes through the heat exchanger (1), so the temperature of the discharged hot water becomes low and the mixing servo valve (3) is activated on the water inlet closing side from point a when the control starts to take effect. be done. For this reason, when the burner is ignited, the flow rate distribution ratio on the hot water side (heat exchanger side) increases, resulting in a large overshoot at point b. In order to suppress this overshoot, the mixing servo valve (3) is operated to the side when the water enters. By repeating this operation, the hot water temperature will converge to the set temperature, but as mentioned above, the control overshoot is large, so it takes a relatively long time for the hot water temperature to converge to the set temperature. There was a problem.

The present invention has been made in view of the above circumstances, and includes:
It is an object of the present invention to provide a method of controlling a mixing servo valve that can improve the tap water characteristics when hot water is re taped.

[Means for solving problems]

In the mixing servo valve control method according to the present invention,
In order to achieve the above object, the operation of the mixing servo valve is specifically stopped until the tapped water temperature rises to the set temperature when hot water is re-discharged.

〔Example〕

The present invention will be explained in detail below with reference to figures. FIG. 1 is a diagram 70 showing the control flow of an embodiment of the present invention. In this mixing servo valve control method,
First, it is determined whether the hot water temperature is a cold start, which is 10 degrees Celsius or more lower than the set temperature, or a hot start, where the hot water temperature is higher than the set temperature (Sl). In the case of a cold start, the mixing servo valve is operated in the same way as in the past, and the water volume is throttled to continue to rise 5: (S2). In the case of a hot start, it is determined whether the set temperature has been changed (S3), and then it is determined whether the outlet temperature is below the set temperature (S4). Note that whether or not the set temperature has been changed is determined by comparing the settings stored in the memory during the previous steady combustion with the set temperature at the time of re-tapping the hot water. If the set temperature has been changed,
When the outlet temperature exceeds the set temperature, the mixing servo valve (3) is operated to open the water inlet (S2).

If the hot water temperature is below the set temperature, the heat exchanger (1
), the time for performing feedforward control of gas H is determined from the flow rate, set temperature, and inlet water temperature, and it is determined whether or not it is within that time (S5).In other words, in the case of a hot start, the after-boiling Since the correct outlet temperature cannot be obtained, feed puncture control is canceled and only feedforward control is performed for a predetermined time.If the feedforward control time is exceeded, mixing is performed to quickly bring the outlet hot water temperature closer to the set temperature. Servo valve (3
) is operated to the water entry closing side (S2), and if the time is within, the mixing servo valve (3) is stopped (S6).
.

In this way, if there is a hot start when hot water is re-discharged, the mixing servo valve (3) is turned to the water inlet closing side! I
By stopping IIJ operation until the outlet temperature reaches the set temperature, the overshoot caused by the initial water entry closing side operation can be reduced, as shown in diagram M2, and the outlet temperature reaches the set temperature in a relatively short time. It will be stabilized.

〔Effect of the invention〕

As explained above, in the mixing servo valve control method according to the present invention, when hot water is re-discharged, the set temperature is not changed and the mixing servo valve is not operated until the tapped water temperature rises to the set temperature when hot start is performed. Therefore, the overshoot after ignition, which occurs as a reaction to the closing of the mixing servo valve at the initial stage of re-dispensing, is reduced, and the effect of quickly stabilizing the discharging γ3 temperature can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a 70-chart of an embodiment of the present invention, and FIG. 2 is a hot water supply diagram of the present invention. FIG. 3 is a schematic diagram of an instant water heater according to the present invention. FIG. 4 is a 70-chart of a conventional example, and FIG. 5 is a hot water discharge characteristic diagram thereof. (1)...Heat exchanger (2)...Cold water passage (3)...Mixing servo valve (4)...Temperature detector (5)...Controller 11th Kudzu 4-mouth

Claims (1)

[Claims] The mixing servo valve is installed at the confluence of the heat exchanger outlet and the cold water passage that bypasses the heat exchanger, and controls the distribution ratio of hot water so that the hot water temperature detected by the temperature sensor matches the set temperature. A method for controlling a mixing servo valve, characterized in that the operation of the mixing servo valve is stopped until the temperature of hot water rises to a set temperature when hot water is tapped.