JPH0651843A - Flow controller - Google Patents

Abstract

PURPOSE:To improve stability and quick responsiveness by preventing flow overshoot at the time of opening a valve in the case of flow feedback control using a flow sensor and a motor concerning the flow controller for supplying/ stopping fluid and adjusting flow. CONSTITUTION:A duct provided with two entrances 18 and 19 and one exit 20 at velocity corresponding to set flow (a) at the time of opening the valve is equipped with two valve elements 22 and 24 linked to one valve shaft and at the central position of the valve shaft, any one of two valve elements is selectively opened corresponding to movement to right and left with the rotation of a motor 12 from the central position of the valve shaft. This device is provided with a valve opening time motor control part 31 to drive the motor 12 at the velocity corresponding to the set flow in the case of opening the valve until getting a flow signal at a flow calculation part 14. Therefore, the motor 12 is driven slowly at the time of small set flow, driven quickly at the time of large set flow and operated so as to prevent the overshoot of flow caused by the delay of flow detection at the time of reducing the set flow, and the control at the time of opening the valve can be stably performed in the shortest time corresponding to the set flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply flow rate control device for preventing hot water from flowing out in a bathroom, washbasin, kitchen or the like, and for obtaining a desired flow rate.

[0002]

2. Description of the Related Art Conventionally, there has been a hot water supply apparatus of this type as shown in FIG.

A valve seat 4 is provided on a body 1 between a flow passage inlet 2 and a flow passage outlet 3, a valve shaft 6 connected to a valve body 5 and a spring 7 for urging the valve body 5 are provided. 6, a rotary straight line exchange screw 9, a motor 12 that drives the valve shaft 5 to rotate via the gear 10 and the gear 11, a flow rate sensor 13, a flow rate calculation unit 14, and a flow rate signal from the flow rate calculation unit 14. The feedback control unit 15 controls the speed of the motor 12 in accordance with the difference between the flow rate and the set flow rate, the cam 16 integrated with the gear 11, and the position detector 17.

FIG. 4 shows the characteristics of the feedback control unit 15. The motor 12 is driven at a speed proportional to the flow rate error which is the difference between the flow rate signal and the set flow rate, and the valve body 5 is adjusted in the opening or closing direction to control the flow rate. When the signal almost matches the set flow rate, the motor 12 is stopped and the flow rate flowing out from the flow rate outlet 3 is adjusted to be equal to the set flow rate. In the range in which the flow rate error in FIG. A is small, the speed is proportional to the error, but in FIG.
Since the speed of the motor 12 is limited within the range of the flow rate error above a certain value, the motor speed becomes constant.

[0005]

However, the conventional structure as described above has the following problems.

In the above structure, the position detector 17 detects the closed position of the valve body 5 with certainty so that the valve shaft 6 is located further to the right from the position where the valve body 5 contacts the valve seat 4. The position where the tip of 6 is separated from the valve body 5 is detected as the closed position.

FIG. 5 is a characteristic diagram of the flow rate change when the valve is opened.
When performing the valve opening operation from the closed state, the motor 12 is rotated to drive the valve shaft 6 to the left at the time A from the position where the position detector 17 detects the closed position. The fluid does not flow until the body 5 is pushed. Further, when the valve shaft 6 pushes the valve body 5 open, and the fluid flows to the flow path outlet 3 at time B, the water amount sensor 13 turns to generate a pulse signal. The flow rate calculation unit 14 measures the time T of one cycle of the pulse signal of the flow rate sensor 13 and obtains the reciprocal of the time to obtain the flow rate signal which is the flow rate per unit time. Therefore, since the flow rate can be calculated only at time C when at least the second pulse signal comes, the detected flow rate signal is always delayed from the actual flow rate. Further, the flow rate sensor 13 usually has a structure in which the impeller is rotated by the flow of fluid, and a delay due to the inertia of the impeller is further added.
The flow rate signal becomes zero until the flow rate signal is obtained when the valve is opened, and the control characteristic of FIG. 4 causes the motor to move at the maximum speed in the range B regardless of the magnitude of the set flow rate. Feedback control is applied from the time point C in FIG. 5 so as to be equal to the set flow rate. However, the flow rate when the set flow rate in FIG. 5D is small exceeds the set flow rate at the time point C and an overshoot occurs. When the set flow rate in FIG. 6E is large, overshoot does not occur.

In order to eliminate the overshoot, the maximum speed of the motor 12 may be lowered, and then, the time for moving the range until the valve shaft 6 hits the valve body 5 (see FIG. 5).
(The time from time point A to time point B) becomes longer, and the delay from when the valve opening command is issued until the fluid actually starts to flow becomes impaired in operability.

The present invention aims to solve the above problems and to realize a flow rate control device having good operability by preventing overshoot at the time of valve opening when the set flow rate is small and shortening the time of valve opening operation. Is.

[0010]

In order to achieve the above object, the present invention replaces the feedback control section with a speed corresponding to a set flow rate until a flow rate signal is obtained when the valve is opened from the closed position. The motor controller for opening the valve is provided to drive the motor.

[0011]

With this structure, when the set flow rate is large when the valve is opened, the motor is driven at a high speed, and when the set flow rate is small, the motor is driven at a low speed, and it is possible to prevent overshoot of the flow rate when the set flow rate is small. , When the set flow rate is large, it works to reduce the delay.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, the first inlet 18 into which hot water flows
A second inlet 19 through which water flows and one outlet 20,
Between the first inlet 18 and the outlet 20, the first valve seat 21 and the first
Of the valve body 22 of the second inlet 19 and the second outlet 20 between the second
The valve seat 23 and the second valve body 24 are provided. The first valve body 22 and the second valve body 24 are respectively provided with a first spring 25 and a second spring 26 for biasing in the closing direction, and the valve shaft 6 penetrates the second valve body 24. And its tip is slidably connected to the hole 27 of the first valve body 22, and the stop ring 28
Is in contact with the second valve body 24. An O-ring 29 is provided in the penetrating portion between the second valve body 24 and the valve shaft 6 to seal the sliding portion. A flow rate sensor 13 is provided at the outlet 20,
The signal of the flow rate sensor 13 has its period measured by the flow rate calculation unit 14 and the flow rate signal is calculated. The flow signal is compared to the set flow signal. Then, the feedback control unit 15 which inputs the deviation signal drives the motor 12 to rotate the valve shaft 6 by the gear 11 and the gear 10, and thrusts the valve shaft 6 by the screw portion 8 of the valve shaft 6 and the rotary straight line conversion screw 9. Drive in the direction.
The gear 11 is provided with a cam 16 and a position detector 17, and detects the center position of the valve shaft 6. A flow rate determination detection section 30 is provided in conjunction with the flow rate calculation section 14, and transmits a flow rate detection timing signal to the motor control section 31 when the valve is open. When the valve is opened, the motor control unit 31 is connected with a hot water discharge / stop switch 32, a water discharge / stop switch 33, and a set flow rate signal, the output of which drives the motor 12 in place of the feedback control unit 15 by the changeover switch 34. .

With the above arrangement, when the valve shaft 6 is at the central position, both the first and second valve bodies 22 and 24 are in contact with the first valve seat 21 and the second valve seat 23, respectively, and the outlet 2
There is no flow at 0.

FIG. 2 is a characteristic diagram showing changes in motor speed and flow rate when the valve is opened. The solid line shows the characteristic when the set flow rate is small, and the wavy line shows the characteristic when the set flow rate is large.

When the set flow rate flowing out from the outlet 20 is small and the tapping / stopping switch 32 is operated at the time point F, the motor control unit 31 at the time of valve opening moves the motor 12 in the direction of moving the valve shaft 6 to the left. Drive at a low G speed. Then, the second valve body 24 slides on the O-ring 29 while the second valve body 24 is in contact with the second valve seat 23, and at the time point H in FIG. Supply. The flow rate sensor 13 starts rotating, and at the time point I in the figure, the flow rate calculation unit 14 obtains the period T by the pulse signal of the second flow rate sensor 13 and calculates the flow rate signal. At time point I, the flow rate confirmation detection unit 30 transmits a flow rate detection timing signal to the valve opening motor control unit 31, and the control of the motor 12 is switched to the feedback control unit 15. After that, at time J when the flow rate error becomes zero, the motor 12 is stopped and the flow rate is controlled to be equal to the set flow rate. When the set flow rate is small, the motor speed is driven at a low speed of G. Therefore, when the water amount signal is detected at the time point I, the flow rate remains smaller than the set flow rate K and control can be performed without overshooting.

When the set flow rate flowing out from the outlet 20 is large, the motor 12 is in proportion to the set flow rate and at a high speed shown in FIG.
Starts to move, and the valve shaft 6 hits the first valve body 22 earlier than the above, so the valve opens at the time M. Since the valve element 22 is opened at a high speed, the increasing rate of the flow rate is also fast, and at the N point when the second pulse comes, the flow rate P is higher than the flow rate K, but the set flow rate is large, so stable control is achieved without overshooting. To be done.

As described above, when the set flow rate is small, the time up to the time point H becomes long, but no overshoot occurs, and when the set flow rate is large, the valve opening operation can be started quickly at the time point M and starts.

On the other hand, when the water discharge / stop switch 33 is operated, the valve shaft 6 is driven to the right, the first valve body 22 abuts on the first valve seat 21, and the valve shaft 6 has a hole 27. Sliding to the right causes the stop ring 28 to push open the second valve body 24
The water at the inlet 19 is supplied to the outlet 20. Position detector 17
From the closed position detected by
The play up to the hit is similar to that on the hot water side, and is controlled in the same manner as in FIG.

Here, the second inlet 19 on the water side is directly connected to a water source not shown, but in the case of the hot water side, the first inlet 18 is generally connected via a heat source for hot water supply not shown. The pressure of the second inlet 19 becomes higher than the pressure of the first inlet 18, and the change of the flow rate with respect to the change of the opening degree of the second valve body 24 becomes larger than that of the first valve body. Therefore, when the valve is opened, the flow rate is likely to be overshooting.
If the setting is made slower than in the case of 2, similar characteristics at the time of valve opening can be obtained.

As described above, the valve opening time motor control section 31 is operated until the flow rate signal is obtained by the flow rate calculation section 14 when the valve is opened.
Drives the motor 12 at a speed according to the set flow rate,
When the set flow rate is small, the valve bodies 22 and 24 are moved slowly, and when the set flow rate is large, the valve bodies 22 and 24 are moved. Therefore, overshoot of the flow rate due to delay in flow rate detection is prevented, and the valve is opened stably and in the shortest time according to the set flow rate. You can take action.

Further, opening / closing and flow rate adjustment of fluids having different pressures from the inlets 18 and 19 are respectively performed by a plurality of valve bodies 22 and 24 connected to a common valve shaft, and the set flow rate at the time of opening the valve is controlled. The relationship of the motor speeds can be set independently of each other, and the characteristics of the same valve opening time can be obtained by removing the influence of the pressure.

[0023]

As described above, according to the flow rate control device of the present invention, the valve body, the valve shaft, and the motor for driving the valve shaft,
Since it is composed of a motor control unit at valve opening that controls the motor at a speed according to the set flow rate until the flow rate signal is obtained at valve opening, it is slow when the set flow rate is small and large when the set flow rate is large. At this time, the motor is driven quickly to prevent flow rate overshoot due to a delay in flow rate detection, and the valve opening operation can be stably performed in the shortest time according to the set flow rate.

Further, in a flow path having two inlets and one outlet, two valve bodies connected to one valve shaft are provided, and the two valve bodies are closed at the central position of the valve shaft. Select one of the two valve bodies to open by moving from the center position of the shaft, and set the relationship between the motor speed and the set flow rate when the valve is opened to 2
Since it is configured with a motor drive unit that is set individually for each valve body, when opening the valve corresponding to each pressure received by the two valve bodies for fluid from two inlets with different pressures The motor speed of is properly adjusted, the characteristics of the same valve opening time can be obtained excluding the influence of pressure, and the selective opening / closing and flow rate adjustment of the two fluids can be performed with a good operation feeling, and It can be realized at low cost.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a flow rate control device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of motor speed and flow rate when the device is opened.

FIG. 3 is a block diagram of a conventional flow control device.

FIG. 4 is a characteristic diagram of a motor speed with respect to a flow rate error of a conventional flow rate control device.

FIG. 5 is a characteristic diagram of flow rate when the conventional flow rate control device is opened.

[Explanation of symbols]

 6 Valve Shaft 12 Motor 13 Flow Sensor 15 Feedback Control Unit 18 First Inlet 19 Second Inlet 20 Outlet 21 First Valve Seat 22 First Valve Body 23 Second Valve Seat 24 Second Valve Body 25 1 spring 26 2nd spring 31 Motor control unit at valve opening

Claims (3)

[Claims] 1. A flow path having an inlet and an outlet, a valve seat and a valve body provided in the flow path for opening and closing the flow path and adjusting a flow rate, a valve shaft connected to the valve body, and the valve. A motor that drives the shaft, a flow rate sensor provided in the flow path, a feedback control unit that drives the motor by comparing a flow rate signal of the flow rate sensor with a set flow rate, and the flow rate signal is obtained when the valve is opened. Until then, a flow rate control device comprising a valve control motor control section that drives the motor at a speed according to a set flow rate, instead of the feedback control section. 2. A flow rate sensor for generating a pulse signal having a frequency corresponding to a flow rate, and a flow rate calculation unit for measuring a pulse period time of the flow rate sensor and calculating a flow rate signal from the time. Flow control device. 3. A flow path having two inlets and one outlet, two sets of valve seats and valve bodies facing each other corresponding to the two inlets, and one valve shaft of the two valve bodies. In the central position, the two valve bodies are closed, and one of the two valve bodies is independently opened by the movement from the central position.
A flow rate sensor is provided in the flow path that merges with one outlet downstream of the two valve bodies, and the relationship between the motor speed and the set flow rate when the valve is opened is the case where the first valve body is opened and the case where the second valve body is opened. The flow rate control device according to claim 1 or 2, comprising a motor control unit at the time of valve opening, which is set separately when opening the valve.