JP3373700B2 - Flow control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate adjusting device used in a hot water supply device.

[0002]

2. Description of the Related Art In a hot water supply apparatus, a heat quantity F required to bring a hot water discharge temperature Th to a set temperature Ts is calculated from a set temperature Ts, a water entry temperature Tc, and a flow rate Q, and the calculated heat quantity F is applied to a water entry in a heat exchanger. . However, when the calculated heat quantity F exceeds the maximum heating capacity Fmax of the hot water supply apparatus, the outlet water temperature Th cannot be set to the set temperature Ts with the flow rate as it is. Is generally maintained at the set temperature Ts.

A flow rate control device is used to reduce the amount of water entering (= amount of hot water supply). The flow rate adjusting device includes a flow rate control valve and a control unit that controls the flow rate control valve. The flow control valve is provided with a valve body that is movable within the valve body, and the position of this valve body is changed to change the cross-sectional area of the flow passage to adjust the flow rate. The valve element is driven by a motor, and when the control unit receives a flow rate instruction signal from the outside, the control section drives the motor to move the valve element to a target position corresponding to the flow rate.

[0004]

If water stains adhere to the flow passage in the valve body or foreign matter is caught between the valve body and the valve body, the movement resistance of the valve body increases. In the conventional flow rate control device, the motor for moving the valve element is always driven at a constant speed, so the driving force of the motor is also constant, and if the resistance to the movement of the valve element increases, the driving force of the motor increases. May be less than the movement resistance of the valve element and the valve element may not reach the target position. If the control is stopped in such a state that the flow rate does not reach the target value, the hot water supply device cannot be correctly controlled, and the motor may be overloaded.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a flow rate adjusting device capable of performing flow rate adjustment as reliably as possible.

[0006]

SUMMARY OF THE INVENTION A flow rate adjusting device according to the present invention, which has been made to solve the above-mentioned problems, has a valve body driven by a speed variable motor according to a flow rate instruction signal from the outside. In a flow rate control device that adjusts the flow rate by moving to a position corresponding to the instruction signal, a) a valve body position sensor that detects the position of the valve body, and b) within a predetermined time after the flow rate instruction signal is given. When the position of the valve body detected by the valve body position sensor does not reach the corresponding position, a control unit that reduces the drive speed of the motor is provided.

This predetermined time is slightly longer than the time required to move from the initial position to the position corresponding to the flow rate instruction signal at the normal speed of the motor (or from the end of the movable range of the valve body). You can leave it as a long time. If the valve body does not reach the intended position (target position) within this predetermined time after the flow rate instruction signal is given, it means that the valve body is not moving normally for some reason. The control unit reduces the drive speed of the motor. As a result, the driving force of the motor increases, and the possibility of overcoming the movement resistance of the valve element and reaching the target position increases.

A specific example of such a flow rate control device is one in which the valve body is screwed into the valve body with a screw, and the valve body is moved by rotating the valve body by the motor. be able to. In this case, a rotation angle sensor that detects the rotation angle of the valve body can be used as the valve body position sensor.

If the valve body position detected by the valve body position sensor does not reach the target position even after the second predetermined time has elapsed after the drive speed of the motor has been reduced, The control unit preferably outputs an abnormal signal. In response to this abnormality signal, for example, the driving of the motor can be automatically stopped, and the cause of the abnormality can be pursued.

In the above embodiment, the flow rate adjustment defect is detected by detecting the position of the valve element, but the flow rate adjustment defect can also be detected depending on whether or not the flow rate is as planned. That is, in another aspect of the flow rate control device of the present invention, in the flow rate control device that adjusts the flow rate by moving the valve body to the position corresponding to the flow rate instruction signal by the speed variable motor according to the flow rate instruction signal from the outside. A) A flow rate sensor that detects the flow rate of the fluid; b) The flow rate detected by the flow rate sensor does not reach the flow rate (target flow rate) corresponding to the flow rate instruction signal within a predetermined time after the flow rate instruction signal is given. In this case, a control unit that reduces the drive speed of the motor is provided.

Also in this case, similarly to the above, if the flow rate detected by the flow rate sensor does not reach the target flow rate even after the second predetermined time has elapsed after the drive speed of the motor has been reduced, an abnormal signal is issued. It is better to output it.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A hot water supply apparatus equipped with a flow rate adjusting device according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the hot water supply device of the present embodiment is a one-can-one-water-path hot water supply device in which water supplied from a water inlet 15 is heated by a heat exchanger 12 and tapped from a hot water outlet 16. The water temperature Tc before heating is the water temperature sensor 3
1, the temperature Th of the hot water discharged is detected by the hot water temperature sensor 33. A hot water supply channel 13 that connects the water inlet 15 and the hot water outlet 16 is provided with a flow rate control valve 18 that controls the amount of water flowing through the hot water supply channel 13 and a flow rate sensor 32 that detects the flow rate (hot water supply rate) Q. ing. A valve body position sensor 34 for detecting the position of a valve body, which will be described later, inside the flow control valve 18 is attached.

An open / close valve 24 and a proportional valve 25 are provided in the fuel pipe 23 of the burner 22 for heating the heat exchanger 12. The proportional valve 25 is a flow control valve that adjusts the flow rate of fuel according to a signal from the outside. A fan 26 is provided in the vicinity of the burner 22 and supplies the air required for burning the burner 22.

As shown in FIG. 3, the flow control valve 18 comprises a valve body 40 and a drive unit 41, both of which are connected by a serrated shaft 49 protruding from the valve body 40. As shown in FIG. 4, the valve body 40 includes a valve body 42 and a valve body 43 movably provided therein. The valve body 42 is provided with a fluid inlet 44 and a fluid outlet 48,
The valve body 43 is the bottleneck 4 between the fluid inlet 44 and the fluid outlet 48.
By moving in and out of 5, the flow rate of water passing through the bottleneck 45 is adjusted. The valve body 43 is screwed into the valve body 42 with a screw 47, and the valve body 43 is moved back and forth by rotating a shaft 49 with serrations to adjust the flow rate passing through the bottleneck 45.

The drive unit 41 is provided with a rotary member 51 having a serration hole 50 and a pulse motor 52 for rotationally driving the rotary member 51. In this embodiment, a potentiometer is used as the valve body position sensor 34, and the rotary shaft of the potentiometer is connected to the rotary member 51 of the drive unit 41. The potentiometer may be provided on the valve body 40 side instead of the drive unit 41 side (in this case, the rotary shaft of the potentiometer is fixed to the valve body 43).

The signals Tc, Q, Th and P of the temperature, the flow rate and the valve body position from the respective sensors 31, 32, 33 and 34 are inputted to the control unit 60. The control unit 60 includes a hot water outlet temperature setting unit 6
1 is connected and a signal of the set hot water discharge temperature Ts is input by an operator's input. From the control unit 60, a valve opening / closing signal is sent to the opening / closing valve 24, a valve opening signal is sent to the proportional valve 25, a fan rotation speed signal is sent to the fan 26, and a flow rate instruction signal is sent to the flow rate control valve 18.

The control unit 60 is composed of a computer having a ROM and a RAM, and performs the following control according to a program stored in the ROM in advance. Less than,
The control procedure performed by the control unit 60 will be described with reference to the flowchart of FIG.

First, when the user operates the hot water supply valve 17 to obtain hot water, the flow rate sensor 32 detects the flow rate Q of the water flowing through the hot water supply channel 13. The control unit 60 compares the value Q with a predetermined minimum flow rate Qmin, and if Q ≧ Qmin, starts the process of FIG. First, based on the set hot water temperature Ts set by the hot water temperature setting unit 61, the hot water temperature Tc detected by the hot water temperature sensor 31, and the hot water supply flow rate Q detected by the flow rate sensor 32, the hot water temperature Th is set to the preset temperature Ts. The heating amount F necessary for the calculation is calculated (step S
1). Then, it is determined whether the calculated required heating amount F exceeds the maximum rated heating amount Fmax of the hot water supply device (step S2). If the required heating amount F does not exceed the maximum rated heating amount Fmax, the on-off valve 24 of the burner 22, the proportional valve 25 and the fan 26 are controlled based on the calculated required heating amount F to heat the incoming water (step S3). Actually, the combustion control in step S3 is performed only when the required heating amount F is equal to or more than the predetermined minimum heating amount Fmin, but the details are omitted here.

The calculated required heating amount F is the maximum rated heating amount F.
If it exceeds max, in the heating capacity of this water heater,
It is impossible to heat the incoming water of the flow rate Q to the set temperature Ts. Therefore, in the hot water supply apparatus of the present embodiment, like the general hot water supply apparatus, the hot water supply flow rate is reduced by giving priority to maintaining the hot water outlet temperature Th at the set temperature Ts. In step S4, a flow rate (limit flow rate) Q1 required for that purpose is calculated.
Then, the valve body position signal P1 necessary for setting the flow rate in the flow rate control valve 18 to Q1 is generated (step S5),
This is sent to the flow control valve 18, and the timer t is reset to zero (step S6).

The specific contents of the control of the flow control valve 18 by the valve body position signal P1 in step S6 are as follows. In this embodiment, a motor 52 for driving the valve body 43
The pulse motor is used as. Since the motor 52 and the valve body 43 are mechanically connected to each other via the rotating member 51 and the shaft 49 with serration, the rotation of the motor 52 is directly connected to the movement of the valve body 43, and the pulse motor 52 is connected to
By giving this pulse, the valve body 43 moves by a predetermined distance Δd. Therefore, the valve body 43 is moved to the predetermined position P1.
Since the number N1 of pulses necessary to move to the pulse motor 5 can be known in advance,
By supplying to No. 2, the flow rate Q can be set to the limited flow rate Q1. At this time, the speed (pulse rate) at which pulses are sent to the pulse motor 52 is a predetermined constant value R0. After the flow rate Q is thus limited to Q1, combustion control is performed based on Fmax (step S7).

However, in step S6, the flow control valve 18
However, there is no guarantee that the flow rate of the water flowing through the hot water supply channel 13 is actually the limited flow rate Q1. In fact, there is always a possibility that the valve body 43 will not move due to, for example, deposits of water on the surface of the valve body 42 or the valve body 43, or a foreign substance being caught between the two bodies 42, 43. Therefore, in the hot water supply apparatus of this embodiment, the position P of the valve body 43 is detected by the valve body position sensor (potentiometer) 34, and whether or not the position P is the same as the valve body position signal P1 commanded in step S6. It is checked (step S8). If the position P of the valve body 43 is as instructed, there is no problem, so this processing is ended as it is, but the detected position P of the valve body 43 has not yet reached the target position P1. Is the predetermined time t1 in step S9.
Wait for. As the predetermined time t1, when the pulse motor 52 is driven at the pulse rate R0,
The time is set to be slightly longer than the time t01 required to move the valve body 43 from end to end within the movable range of the valve body 42. If the target position P1 has not been reached even after the elapse of the predetermined time t1, the sending speed (pulse rate) of the pulse given to the pulse motor 52 is reduced to R1 (step S10).

As shown in FIG. 5, since the pulse motor 52 has a characteristic that the torque increases as the pulse rate decreases, the driving torque of the pulse motor 52 increases by the measure of step S10, and some movement resistance is applied. There is a possibility that the valve body 43 can be moved over the vehicle.

Thereafter, as in steps S8 and S9, it is checked again whether or not the position P of the valve body 43 has reached the target position P1 for a predetermined time t2 (steps S11 and S1).
2). This time t2 is set to be slightly longer than the time t02 required to move the valve body 43 from one end of the movable range to the other at the reduced pulse rate R1. If the valve body 43 reaches the target position P during this time, this processing ends there. However, if the valve body 43 does not reach the target position P even after the predetermined time t2, the control unit 6
0 outputs an abnormal signal to the alarm device 62 (step S1).
3). When the valve body 43 does not reach the target position P, the hot water supply flow rate Q is not limited, so the hot water discharge temperature Th is set to the set temperature Ts.
Although it becomes lower than the above, the user can know the cause by the alarm device 62 and can take appropriate measures.

In the above embodiment, whether or not the flow rate Q in the flow rate control valve 18 is the limit flow rate Q1 is checked by detecting the position of the valve body 43 (steps S8 and S11). You may make it check by the output Q of 32. In this case, since it is not necessary to provide the valve body position sensor 34 on the flow control valve 18, the structure can be simplified and the cost can be reduced. Also,
Although a pulse motor was used as the motor 52, it may be a normal DC motor. Also in this case, generally, the torque is increased by decreasing the driving speed of the motor, and there is a high possibility that the movement resistance of the valve element 43 will be overcome and the movement will be restarted.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a one-can-one-channel water heater according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of controlling the hot water supply device according to the embodiment.

FIG. 3 is a schematic configuration diagram of a flow rate control valve and a valve body position sensor used in the hot water supply device according to the embodiment.

FIG. 4 is a sectional view of the flow control valve on the valve body side.

FIG. 5 is a graph showing the relationship between the pulse rate and torque of the pulse motor.

[Explanation of symbols]

12 ... Heat exchanger 13 ... Hot water supply channel 15 ... Water inlet 16 ... Departure gate 40 ... Valve body 41 ... Drive unit 42 ... Valve body 43 ... Valve 44 ... Fluid inlet 45 ... Bottleneck 47 ... screw 48 ... Fluid outlet 49 ... Serration axis 50 ... Serration hole 51 ... Rotating member 52 ... Motor

Front page continuation (72) Inventor Katsumi Daido 43-1, Uozakihama-cho, Higashinada-ku, Kobe City, Japan Nippon Professional Corporation (56) Reference JP-A-5-248701 (JP, A) JP-A-4-47308 ( JP, A) JP 4-295907 (JP, A) JP 62-296210 (JP, A) JP 5-158550 (JP, A) JP 8-161054 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) G05D 7/06 F16K 31/04

Claims (5)

(57) [Claims] 1. A flow rate control device for adjusting a flow rate by moving a valve element to a position corresponding to the flow rate instruction signal by a variable speed motor according to a flow rate instruction signal from the outside. A valve body position sensor for detecting, b) if the position of the valve body detected by the valve body position sensor does not reach the corresponding position within a predetermined time after the flow rate instruction signal is given, A flow rate control device comprising: a control unit that lowers a drive speed. 2. A valve body is provided with a screw that is screwed into the valve body, and the valve body is moved by rotating the valve body by the motor, and the valve body position sensor detects a rotation angle of the valve body. The flow rate adjusting device according to claim 1, which is a rotation angle sensor for detecting the. 3. The position of the valve element detected by the valve element position sensor reaches the corresponding position even after the second predetermined time has elapsed after the control unit has reduced the drive speed of the motor. The flow rate control device according to claim 1 or 2, which outputs an abnormal signal when there is no signal. 4. A flow rate adjusting device for adjusting the flow rate by moving a valve element to a position corresponding to the flow rate instruction signal by a speed variable motor according to a flow rate instruction signal from the outside. A flow rate sensor, and b) control for reducing the drive speed of the motor if the flow rate detected by the flow rate sensor does not reach the flow rate corresponding to the flow rate instruction signal within a predetermined time after the flow rate instruction signal is given. And a flow control device. 5. The control unit, when the flow rate detected by the flow rate sensor does not reach the corresponding flow rate even after the second predetermined time has elapsed after reducing the drive speed of the motor. The flow rate adjusting device according to claim 4, which outputs an abnormal signal.