JPS603723A - Mixing device of hot water and cold water - Google Patents

Abstract

PURPOSE:To prevent overshooting and the generation of high-temperature hot water by driving a valve quickly to a prescribed valve position corresponding to a set temperature in accordance with signals of a hot water temperature detector and a cold water temperature detector and correcting the valve position in accordance with a signal of a mixed hot water temperature detector. CONSTITUTION:Signals of a hot water detector 16 on a hot water path 1, a cold water temperature detector 17 on a cold water path 2, and a temperature setter 12 are led to an initial position setting circuit 18. Signals of a mixed hot water temperature detector 11 on a mixing path 3 and the temperature setter 12 are compared and amplified by a temperature error detecting circuit 19. The output of this circuit 19 and the output signal of a counter 22 are led to a movement range limiting circuit 24, and its output is sent to a valve driving circuit 23, and an input signal is received by the circuit 23 to generate a driving signal of a step motor 10. The motor 10 is driven in the highest speed in accordance with the set hot water temperature and the set cold water temperature to move a hot water-side valve body 5 and a cold water-side valve body 6 to prescribed positions are corrected by the signal of the detector 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application: This invention relates to a hot water mixing device for automatically mixing high-grade 411 hot water and water to produce mixed hot water at a desired temperature.

Structure of the conventional example and its problems As shown in FIG. and a water side valve body are fixed to a valve shaft 7, and are connected to a DC servo motor 10 via a screw feed mechanism 8 and a speed reducer 9.
is driven by. The mixed water temperature is detected by the mixed water temperature detector 11 and compared with the signal from the temperature setting device 12, and the error signal is amplified by the amplifier circuit 13, and the DC servo motor 10 (hereinafter referred to as motor 10) is drive

FIG. 2 (,) shows the relationship between temperature error and motor speed in the conventional example. The motor starts rotating at point (1) where the amplified value of the temperature error becomes the starting electric current of the motor, and as the temperature error increases, the motor speed increases in proportion to it, and the amplification is 1! At point (2), which is determined by the power supply voltage of the I circuit, the 1' Samurai high speed is reached. (1
) to (2) is the proportional operation range.If the temperature error is negative, the direction of rotation of the motor is reversed and the same operation occurs.

FIG. 2(b) shows temporal changes in the operation of the conventional example. When the setting is changed with the temperature setting device 12 in (3), the motor 10 rotates at the maximum speed, and when it enters the proportional operation range in 4), the motor 10 gradually reduces its speed, and the mixed water temperature gradually reaches the set temperature. The motor stops at approach (5). The time it takes for the temperature of the mixed water to stabilize becomes shorter as the proportional gain of the motor speed to the temperature error increases, but there is a limit due to stability during steady state.

If discharging of the mixed hot water is still stopped, the flow in the mixing passage 3 is stopped, the temperature of the hot water near the thermisk 11 drops, the hot water side valve body 5 is fully open, and the water side JP body 6 is fully open, and the valves move to the device. .

When hot water is restarted at step (6), the hot water side valve body will be fully opened.
First of all, in (7), is the mixed water hotter than the set temperature? ! +
;! After that, the motor 10 starts rotating, and the mixed water temperature is gradually corrected, and the motor stops at 8).

Due to the above-described operation, the conventional hot water mixing device has the following drawbacks.

1. The responsiveness of the mixed water temperature when changing the setting rlli'1 degree is poor.

2. If the valve is not driven until the mixed water η1.1 is detected, overshoot is likely to occur.

3. Hot water comes out when the hot water starts. Moreover, it is dangerous because it takes time to stabilize.

The main feature of the F11 is to solve these conventional problems, and has a fast response when changing temperature settings, as well as an overshoot of 1° and a 1.
゜1 Eh, Ega, Eh. □Ya, oh, 1 thing is 1'1 勺.

Structure of the Invention In order to achieve this object, the water source IjIl is provided with a hot water temperature detector in the hot water passage, a water temperature detector in the water passage, and a valve position detector.

With this configuration, the signals from the hot water temperature sensor and the water temperature sensor quickly drive the valve to a predetermined valve position corresponding to the set temperature, and the valve position is further corrected using the signal from the mixed water temperature sensor. It has good responsiveness when changing temperature and has the effect of suppressing unnecessary overshoot and generation of high temperature water.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention is shown in FIGS. 3, 4, and 5.
This will be explained in detail using Figure 6. Note that parts that are the same as those in Figure 1 are numbered the same.

In FIG. 3, in a mixing valve main body 4 having a hot water passage 1, a water passage 2, and a mixing passage 3, a hot water side valve body 5 that adjusts the opening degree of the hot water passage 1 and a hot water side valve body 5 that adjusts the opening degree of the water passage 2 are used. The water-side valve body 6 is connected to the valve shaft 7 by being urged by a spring 14 and abutting against a stop 1IIIi 115. The valve bodies 5.6 are free to slide relative to the valve stem 7, and the spring 14 provides relief when each valve body is fully closed. The valve 1117 is linearly driven by a step motor 10 (hereinafter simply referred to as a motor) via a screw feed mechanism 8 and a speed reducer 9. Hot water temperature detector 16 of hot water passage 1 and water passage 2
Signals from the water temperature detector 17 and temperature setting device 12 are led to an initial position setting circuit 18. The signal from the mixed water temperature detector 11 in the mixing passage 3 and the signal from the temperature setter 12 are compared and amplified by a temperature error detection circuit 19. The limit switch 20 is connected to a switch lever 21 connected to the valve stem.The limit switch 20 detects the valve position when the hot water side valve body is fully closed.

A signal from the limit switch 20 is applied to the reset terminal of the counter 22, and drive pulses corresponding to the upward and downward rotations of the motor of the valve drive circuit 23 are applied to the up and down force terminals. counter 22
The output signal is compared with the output signal of the initial position setting circuit 18 and applied to the valve drive circuit 23, and the temperature error detection circuit 19
The output signal of the movement range limiting circuit 24 and the output signal of the counter 22 are guided to the movement range limiting circuit 24, and the output signal of the movement range limiting circuit 24 is guided to the valve driving circuit 23. The valve drive circuit receives the input signal υ
In response to this, a drive signal for the step motor 10 is generated.

Figure 4 shows the change in the amount of hot water and the amount of water with respect to the valve position (axial displacement of the valve shaft 7).If the pressures of hot water and water are equal, the flow rate ratio of hot water and water is almost determined by the valve position at the end of the mixing passage 3. Even when the overall flow rate is reduced, the absolute value of each Mt 4+'i- changes, but the bIC new ratio remains almost unchanged. Therefore, if the hot water temperature and water temperature are known, the valve position can be approximately determined for the required mixed water temperature.

Next, the operation of this embodiment is shown in the flowchart of FIG.

This will be explained using the operating characteristic diagram shown in FIG. In FIG. 5, when the operation is started, the motor is moved until the limit switch 20 is turned on in step 1 (a), and the counter 22 is set to the reference position for the valve position. Thereafter, since the counter 22 counts the driving pulses of the step motor, the absolute position of the valve can be known. Next, Figure 5(b)
The mixture ratio is determined based on the set temperature, hot water temperature, and water temperature, and the step motor 10 is driven at the maximum speed to move the valve to the initial position shown in FIG. 4 (1) in FIG. 4 (FIG. 5 (C)). Figure 5 (C)
generates a correction pulse with a frequency proportional to the temperature error,
If the value of the counter that detects the valve position is within the predetermined correction operation range (FIG. 4 (2)), correction/%/less is applied to the motor to compensate. When the temperature error disappears, the frequency of the correction noise ζ pulse is zero, so the motor stops (e to f).

In (g), changes in the set temperature, hot water temperature, and limescale 1 are detected, and if there is a change, the process goes to (h), and if there is no change, the process returns to (i) and repeats the operation.

In FIG. 6, after the reference position of the valve is determined, the motor drives the valve at the maximum speed to the valve initial position (1).

From tl, the valve position is compensated at a speed corresponding to the temperature error, and when the temperature error disappears, the motor is set to 12.

Since the valve moves slowly between t and t2, oat shoe 1 does not occur. Variations in the mixing ratio with respect to the valve position, errors in initial settings, changes in hot water and water supply pressure, etc. are absorbed by the feedbank operation during this period, and an accurate mixed hot water temperature can be obtained. When the set temperature is changed at t3-, the motor is again driven at the maximum speed to drive the valve to a new valve initial position (2), and correction operations are performed in the same manner until the temperature error disappears.

When dispensing hot water is stopped at t4, the mixed hot water temperature decreases due to heat radiation, the hot water side valve body opens, and the water side valve body starts a correction operation in the direction of closing. However, at t5, the valve that exceeds the correction operation range will not move any further. do not have. When hot water starts dispensing again at t6, the valve position has not moved significantly from the initial setting position (2), so hot water will not be dispensed suddenly, and only a slight overshoot will occur at t7, which can be quickly corrected. The temperature of the mixed water becomes stable.

As described above, according to the hot water mixing device of the present invention, the following effects can be obtained.

(1) Install a water temperature detector in the water passage, a hot water temperature detector in the hot water passage,
A valve position detector is provided to detect the valve position, and the valve is driven at high speed to the valve initial position determined by the set temperature of the temperature setting device, the water temperature, and the hot water temperature. Since the valve position is corrected based on the signal from the device, the response when changing the temperature setting is extremely fast, and the desired mixed hot water temperature is quickly obtained with good stability during steady state.

(2) The valve position detector consists of a limit switch that detects one end of the valve's movement range and a counter that detects motor drive pulses, so the limit switch can also be used as a limit switch for stopping the motor, making the structure more complicated. This can be achieved without having to do anything, and it can be done at low cost. Also, the counter is
If the control circuit is configured with a microcomputer, can it be realized with software? Since no external circuit is required for i, a low-cost device can be provided.

(3) The movement range of the valve position correction by the mixed water temperature sensor,
Because the valve was limited to a small range around the initial f1 sea position,
Prevents the valve from moving more than necessary due to transient changes and maintains a stable water temperature! I can. -T after temporarily stopping hot water supply at qjt] 3 hot water discharges can prevent the generation of dangerously high temperature hot water.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing a conventional hot water mixing device, Figure 2 is an operating characteristic diagram of a conventional example, and Figure 2 (a) is a characteristic diagram showing the relationship between temperature error and motor speed. (b) is a characteristic diagram showing the set temperature, mixed water temperature, and motor speed against time;
The figure is a configuration diagram showing an embodiment of the present invention, Fig. 4 is a characteristic diagram showing the relationship between valve position, water flow rate, and hot water flow rate in an embodiment of the present invention, and Fig. 5 is an operation of an embodiment of the water source 111. FIG. 6 is a flow chart showing operating characteristics of set temperature, mixed hot water temperature, motor speed, and valve position with respect to time in an embodiment of the present invention. 1...Hot water passage, 2...Water passage, 3...
Mixing passage, 4...Mixing valve body, 5...Hot water side valve body, 6...Water side valve body, 7. Valve shaft, 10...Step motor, 11...Mixing Water temperature detector, 12...
・Temperature setting device, 16... Hot water temperature detector, 17-・
Water temperature detector, 18...Initial position setting circuit, 19...
・Temperature error detection circuit, 20 limit switch, 22・
- Counter, 23... Valve drive circuit, 24... Movement range limiting circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 (a) Figure 3 Figure 4 A moving position) Figure

Claims (3)

[Claims] (1) a mixing valve that differentially adjusts the opening degree of a water passage and a hot water passage; a drive unit that drives the mixing valve; and a valve position detector that detects the valve position of the mixing valve; a mixing passage for obtaining mixed hot water by merging the water passage and the hot water passage; a water temperature detector provided in the water passage; a hot water temperature detector provided in the hot water passage; a mixing water temperature sensor, and a temperature setting device for setting the mixing water temperature; A hot water mixing device configured to drive a hot water mixing device and further correct a valve position based on signals from the mixed hot water temperature detector and temperature setting device so as to eliminate a hot water temperature error. (2) a limit switch in which the driving part is a step motor and the valve position detector detects one end of the movement range of the valve body;
The hot water mixing device according to claim 1, comprising a counter for counting drive pulses applied to the step motor. (3) Mixed rJA ril! Claim No. 1, wherein the movement range of the valve position correction by the detector is limited to a small value with respect to the entire valve movement range, with the initial valve position determined by the signals of the water temperature detector, hot water temperature sensor, and temperature setting device being the center. Yusui '611 described in Item 1: Combiner.