JPH10320057A - Flow rate control valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control a flow rate and to perform miniaturizing by turning a valve body itself to a part of a flow meter, turning a part for changing the flow of fluid to the valve body only, calculating the flow rate based only on the flow change and directly controlling the opening degree of the valve body. SOLUTION: This flow rate control valve device 1 is provided with a butterfly valve 4 as the valve body provided in the middle of a pipe line 2 where air as the fluid is circulated. For the butterfly valve 4, the opening degree is made controllable by an actuator 6. A pressure sensor 8 can measure a static pressure on the upstream side of the valve 4 and the other pressure sensor 10 can measure the static pressure on the downstream side of the valve 4. Pressure signals measured in the two pressure sensors 8 and 10 are inputted to a control means 12. In the control means 12, the difference ΔP of the pressures detected in the pressure sensors 8 and 10 is calculated, the difference ΔP is substituted to an expression, an average flow speed Um is calculated and the opening degree of the butterfly valve 4 is adjusted by controlling the actuator 6 so as to turn the average flow speed Um to a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve device, and more particularly, to a flow control valve device in which a valve body itself is a part of a flow meter and a separate flow meter does not need to be mounted.

[0002]

2. Description of the Related Art In a conventional flow control valve device, a flow meter is disposed downstream of a valve body separately from a valve body such as a butterfly valve provided in the middle of a pipeline, and the flow rate is measured by the flow meter. The opening degree of the valve body is controlled so that the flow rate signal becomes constant. As the flow meter, for example, a flow meter using an orifice, a flow meter using a venturi tube, a flow meter that measures a flow rate by measuring a generation frequency of a Karman vortex street, and the like are known.

[0003]

However, all of these flowmeters dispose a fluid resistor in the flow of the pipe and measure the change in the flow of the pipe caused by the fluid resistor. The average flow velocity is obtained, and the flow rate is measured. For this reason, conventionally, in order to measure the average flow velocity separately from the valve element, it is necessary to arrange a flow resistor in the pipeline, which essentially has a problem that the pipeline resistance increases. Was. When the fluid in the pipeline is forcibly distributed by a pump or a blower, etc., an increase in the resistance of the pipeline causes an increase in the output of the pump or the blower, which may cause noise and the like. It is important to control.

[0004] Conventionally, a flow meter is mounted separately from the valve body, the flow in the pipe is changed by the flow meter, and the flow rate of the valve body is changed based on a signal measured by the flow meter. The degree of opening is controlled, and the flow in the pipeline is also changed by the valve element. That is, conventionally, it is necessary to change the flow in the pipeline at least twice for the flow rate control, and the change of the flow over the two times hinders accurate flow rate control. Also have.

Another problem is that the valve element and the flow meter must be arranged at positions sufficiently separated from each other in order to prevent mutual interference between the valve element and the flow meter, which hinders accurate measurement of the flow rate. Have. This is particularly problematic when the flow control valve device must be installed in a narrow space or in a short line.

The present invention has been made in view of such circumstances, and the valve body itself is a part of the flow meter, so that there is no need to separately install a flow meter, and the resistance of the pipeline can be minimized. Moreover, it is an object of the present invention to provide a compact flow control valve device capable of accurate flow control.

[0007]

In order to achieve the above object, a flow control valve device according to the present invention comprises a valve body provided in the middle of a pipe through which a fluid flows, and an opening degree of the valve body. An actuator to be changed, and a pressure for measuring a pressure difference (ΔP) between an upstream static pressure of a pipe located upstream of the valve element and a downstream static pressure of a pipe located downstream of the valve element. Based on the sensor and the pressure difference (ΔP) detected by the pressure sensor, the average flow velocity (Um) of the fluid flowing through the pipeline is calculated from the following equation, and the average flow velocity (Um) becomes a predetermined value. Control means for controlling the actuator to adjust the opening of the valve element.

[0008]

(Equation 2)

The pressure sensor includes a first pressure sensor mounted on a wall of a pipe located upstream of the valve body, and a second pressure sensor mounted on a wall of a pipe located downstream of the valve body. It is preferable to have a pressure sensor.

[0010] Assuming that the cross-sectional reference dimension of the pipe is (D),
The first pressure sensor is mounted at a position of 1 × D or more on the upstream side of the valve body, and the second pressure sensor is mounted at a position of 2 × D or more on the downstream side of the valve body. It is preferred that If these pressure sensors are too close to the valve, the above relational expression may not be satisfied due to the influence of the valve.

The first pressure sensor is mounted at a position about 2.75 × D upstream of the valve body, and the second pressure sensor is mounted on the second pressure sensor.
It is further preferred that the pressure sensor is mounted at a position 4.33 × D away from the downstream side of the valve body.

When the valve element is a butterfly valve,
Preferably, the index (n) in the above equation is about 1.
In this case, when the cross section of the conduit is circular, it is preferable that the coefficient (C) in the mathematical expression is about 2.0. When the cross section of the conduit is rectangular, the coefficient (C) in the above equation is preferably about 1.7.

When the valve element is a gate valve and the cross section of the pipe is circular, the index (n) in the above equation is about 1.12, and the coefficient (C) in the above equation is Preferably it is about 1.9. Further, the valve element is a gate valve,
The cross section of the conduit is rectangular, and the opening ratio (β) is 0.
In the case of 1 or more and 0.3 or less, the index (n) in the above formula
Is about 0.96, and the coefficient (C) in the above equation is about 2.
It is preferably 5. Further, when the valve element is a gate valve, the cross section of the conduit is rectangular, and the opening ratio (β) is larger than 0.3 and 0.8 or smaller, the index (n) in the above equation is About 1.2, and the coefficient (C) in the above equation
Is preferably about 1.7.

The Reynolds number of the fluid in the pipeline controlled by the flow control valve device according to the present invention is 1.0 × 10 ⁴ to
It is preferably about 3.0 × 10 ⁵ .

[0015]

The present inventors have repeated experiments on the general relational expression between the static pressure difference before and after the valve placed in the pipe and the average flow velocity, and as a result, the type of the valve and the cross-section of the inside of the pipe have been confirmed. Regardless of the shape and the like, in a wide range of Reynolds number, the loss coefficient K of the fluid flow based on the valve element placed in the pipeline is [(1-
β) / β ² ] was found to be proportional to the nth power, and the present invention was completed. Conventionally, the loss coefficient due to the valve element is given in a diagram or a table for each type of valve or cross-sectional shape of the pipe, and has not been generalized. It was impossible.

In the present invention, the loss coefficient K of the fluid flow based on the valve element placed in the pipeline has been successfully generalized using the opening ratio β. Thus, in the present invention, the average flow velocity (Um) of the fluid flowing through the pipeline is calculated from the above equation by using the valve body itself as a part of the flow meter and calculating the static pressure difference before and after the valve body. I made it possible. Then, by controlling the actuator from the control means to adjust the opening degree of the valve body so that the average flow velocity (Um) becomes a predetermined value, a flow at a constant flow rate can be realized.

Therefore, according to the present invention, the valve body itself becomes a part of the flow meter, and it is not necessary to separately mount a flow meter, and the resistance of the pipeline can be minimized. Moreover,
In the present invention, only the valve element changes the flow of the fluid, and the flow rate is calculated and the opening degree of the valve element is directly controlled based on only the flow change, so that accurate flow rate control is possible. Further, since a separate flow meter is not required, a compact flow control valve device can be realized.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is a schematic configuration diagram of a flow control valve device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of use of the flow control valve device according to the embodiment, and FIG. Schematic configuration diagram of a flow control valve device according to the embodiment of FIG. 4, FIG. 4 is a cross-sectional view of a main part of a valve device according to still another embodiment of the present invention,
FIG. 5 is a graph showing the relationship between the loss coefficient of the butterfly valve and the opening ratio, FIG. 6 is a graph showing the relationship between the loss coefficient of the gate valve and the opening ratio, and FIG. 7 is a graph showing the relationship between the cock valve and the opening ratio. It is.

First Embodiment As shown in FIG. 1, a flow control valve device 1 according to this embodiment
Has a butterfly valve 4 as a valve body provided in the middle of a pipe 2 through which air as a fluid flows. The opening of the butterfly valve 4 can be controlled by an actuator 6. As the actuator 6, for example, a step motor is used.

The cross section of the conduit 2 is not particularly limited, but is, for example, circular or rectangular. When the cross section of the pipe 2 is circular, the butterfly valve 4 also has a circular shape, and the cross-sectional reference dimension D of the pipe 2 is the inner diameter of the pipe 2. When the cross section of the pipeline 2 is rectangular, the butterfly valve 4 is also rectangular, and the reference cross-sectional dimension D of the pipeline 2 is the length of one side of the rectangle.

Air flows in the direction of arrow A inside the pipe 2. On the upstream side of the butterfly valve 4, the first wall is located at a distance L1 = 2.75 × D from the valve 4.
A pressure sensor 8 is mounted. The pressure sensor 8 can measure a static pressure on the upstream side of the valve 4.

A second pressure sensor 10 is mounted on the pipe wall downstream of the butterfly valve 4 at a distance L2 = 4.33 × D from the valve 4. The pressure sensor 10 can measure a static pressure on the downstream side of the valve 4.

The pressure signals measured by the pressure sensors 8 and 10 are input to the control means 12. The control means 12 calculates the difference ΔP between the pressures detected by the pressure sensors 8 and 10, and substitutes this ΔP into the following equation to calculate the average flow velocity Um.

[0025]

(Equation 3)

In this embodiment, since the valve body is the butterfly valve 4, a numerical value of 1 is used as the index n in the above equation. When the cross section of the conduit 2 is circular, the coefficient C is a numerical value of 2.0 when the aperture ratio β is in the range of 0.134 or more and 0.913 or less. When the aperture ratio β is in the range of 0.06 to 0.826, a numerical value of 1.7 is used. Further, the opening ratio β in the above equation changes according to the opening angle θ of the butterfly valve 4 shown in FIG. 1, but is a unique value determined by the opening angle θ. Therefore, if the pressure difference ΔP is obtained, the average flow velocity Um of the pipeline is uniquely calculated from the above equations (1) and (2). It has been confirmed that the relational expression (2), as shown in FIG. 5, agrees very well with the experimental results. In FIG. 5, circles in the figure indicate the experimental results in the pipe 2 having a circular cross section, and squares indicate the experimental results in the pipe 2 having a rectangular cross section. The result shown in FIG. 5 is based on the Reynolds number (Um × D /
ν) is a wide range (about 1.0 × 10 ^{4 to} 3.0 × 10 ⁵ )
It has been confirmed that this holds. This means that a wide range of average flow velocity Um can be measured. In the Reynolds number, ν is the kinematic viscosity coefficient of the fluid.

[0027] If the calculated average velocity Um is, the average flow velocity Um to the cross-sectional area A0 of the conduit 2 (when the conduit cross-section is circular, [pi] D ^2/4) by multiplying the conduit 2 The flow rate can be calculated. These calculations are performed by the control unit 12 shown in FIG. 1, and the control unit 12 sends a signal to the actuator 6 so that the flow rate becomes a set value,
The opening angle θ of the butterfly valve 4 is changed. The set value of the flow rate can be set based on an input signal not shown. The input signal is not particularly limited.
Examples include an input signal from a keyboard or a setting button, an electric signal from another device, and the like.

In the present embodiment, the fluid flow loss coefficient K based on the butterfly valve 4 placed in the pipe line 2 is determined by the opening ratio β
We succeeded in generalizing using. Accordingly, in the present embodiment, the average flow velocity (Um) of the fluid flowing through the pipeline is calculated from the above equation by using the butterfly valve 4 itself as a part of the flow meter and determining the static pressure difference before and after the valve 4. Made it possible to do so. And this average flow velocity (Um)
By controlling the actuator 6 from the control means 12 to adjust the opening of the butterfly valve 4 so that the value of the control valve 12 becomes a predetermined value, a flow of a constant flow rate can be realized.

Therefore, in the present embodiment, the butterfly valve 4 itself becomes a part of the flow meter, so that it is not necessary to attach a separate flow meter, and the resistance of the pipeline 2 can be minimized. Moreover, in the present embodiment, only the butterfly valve 4 changes the flow of the fluid, and the flow rate is calculated and the opening degree of the butterfly valve 4 is directly controlled based on only this flow change. It becomes possible. Further, since a separate flow meter is not required, a compact flow control valve device can be realized.

Second Embodiment In this embodiment, as shown in FIG. 2, the flow control valve device 1 according to the embodiment shown in FIG. The flow rate of air flowing in from the direction is controlled. In the automobile engine 14, since it is necessary to accurately control the flow rate of the intake air in order to control the air-fuel ratio, the flow control valve device 1 according to the present embodiment can be suitably used.
In addition, the butterfly valve 4 itself is a part of the flow meter, the flow control valve device 1 according to the present embodiment is compact,
It can be preferably used for automobiles.

Third Embodiment In this embodiment, as shown in FIG. 3, a gate valve 4a is used as a valve element. A linear motor is used as the actuator 6a for adjusting the opening of the gate valve 4a. Other configurations are the same as those of the first embodiment, and the equations (1) and (2) used in the first embodiment hold. However, they differ in the following points.

In the present embodiment, the shape of the gate valve 4a conforms to the cross section of the pipeline 2, and is circular when the cross section is circular and rectangular when the cross section is rectangular. Pipe line 2
Is a circular cross section, the index n is 1.12 and the coefficient C is 1.9 in the equation (2). When the cross-sectional shape of the conduit 2 is rectangular and the opening ratio β is 0.1 or more and 0.3 or less, the index n in the above equation is 0.9.
6, and the coefficient C in the above equation is 2.5. Further, the sectional shape of the conduit 2 is rectangular, and the opening ratio β is 0.3.
When the value is larger than 0.8, the index n in the above formula is used.
Is 1.2, and the coefficient C in the above formula is 1.7.
These relationships were obtained from the experimental results shown in FIG. In FIG. 6, circles indicate results when the cross-sectional shape of the pipeline 2 is circular, and squares indicate results when the cross-sectional shape of the pipeline 2 is rectangular.

In the present embodiment, the loss coefficient K of the fluid flow based on the gate valve 4a placed in the pipeline 2 has been successfully generalized using the opening ratio β. Thereby, in the present embodiment, the gate valve 4a itself is used as a part of the flow meter,
By calculating the static pressure difference before and after the valve 4a,
It has been made possible to calculate the average flow velocity Um of the fluid flowing through the pipeline. Then, by controlling the actuator 6a from the control means 12 to adjust the opening of the gate valve 4a so that the average flow velocity Um becomes a predetermined value, a flow at a constant flow rate can be realized.

Therefore, in this embodiment, the gate valve 4a
The part itself becomes a part of the flow meter, so that it is not necessary to attach a separate flow meter, and the resistance of the pipe line 2 can be minimized. Moreover, in the present embodiment, the only part that changes the flow of the fluid is the gate valve 4a, and the flow rate is calculated and the opening degree of the gate valve 4a is directly controlled based on only this flow change. It becomes possible. Further, since a separate flow meter is not required, a compact flow control valve device can be realized.

Fourth Embodiment In this embodiment, as shown in FIG. 4, a cock valve 4b is used as a valve body. As an actuator for adjusting the opening of the cock valve 4b, for example, a step motor is used.
Other configurations are the same as those of the first embodiment.
Equations (1) and (2) used in the embodiment hold. However, they differ in the following points.

In this embodiment, the communication passage 5 of the cock valve 4b
Is in accordance with the cross section of the conduit 2 and is circular when the cross section is circular, and is rectangular when the cross section is rectangular.
When the cross-sectional shape of the conduit 2 is circular and the opening ratio β is 0.09 or more and smaller than 0.5, the index n is approximately 1 and the coefficient C is approximately 4.4. . Further, the cross-sectional shape of the conduit 2 is circular, and the opening ratio β is 0.5 or more.
When the value is 85 or less, the index n in the above equation is about 1.4, and the coefficient C in the above equation is about 2.8.

When the sectional shape of the pipe 2 is rectangular and the opening ratio β is 0.11 or more and less than 0.5,
The exponent n in the above equation is about 1, and the coefficient C in the above equation is
Is about 4.0. Further, when the cross-sectional shape of the pipeline 2 is rectangular and the opening ratio β is 0.5 or more and 0.85 or less,
The index n in the above equation is about 1.4, and the coefficient C in the above equation is about 2.8. These relationships were obtained from the experimental results shown in FIG. In FIG. 7, circles indicate results when the cross-sectional shape of the pipeline 2 is circular, and squares indicate results when the cross-sectional shape of the pipeline 2 is rectangular.

In this embodiment, the loss coefficient K of the fluid flow based on the cock valve 4b placed in the pipe line 2 has been successfully generalized using the opening ratio β. Thus, in the present embodiment, the average flow velocity Um of the fluid flowing through the pipeline is calculated from the above equation by using the cock valve 4b itself as a part of the flow meter and determining the static pressure difference before and after the valve 4b. Was made possible. Then, by controlling the actuator from the control means to adjust the opening degree of the cock valve 4b so that the average flow velocity Um becomes a predetermined value, a flow at a constant flow rate can be realized.

Therefore, in this embodiment, the cock valve 4
b itself becomes a part of the flow meter, so that it is not necessary to attach a separate flow meter, and the resistance of the pipeline 2 can be minimized. Moreover, in the present embodiment, the only part that changes the flow of the fluid is the cock valve 4b, and the flow rate is calculated and the opening degree of the cock valve 4b is directly controlled based on only this flow change. It becomes possible. Further, since a separate flow meter is not required, a compact flow control valve device can be realized.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

For example, the pressure difference before and after the valves 4, 4a, 4b is not detected by the separate pressure sensors 8, 10, but the static pressure at the portion where these sensors 8, 10 are located is led to a differential pressure gauge. The differential pressure may be directly detected by a differential pressure gauge.

[0042]

As described above, according to the present invention, the valve element itself becomes a part of the flow meter, so that it is not necessary to separately mount a flow meter, and the resistance of the pipeline can be minimized. it can. Moreover, in the present invention, only the valve element changes the flow of the fluid, and the flow rate is calculated and the opening degree of the valve element is directly controlled based on only the flow change, so that accurate flow rate control is possible. . Further, since a separate flow meter is not required, a compact flow control valve device can be realized.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing an example of use of the flow control valve device according to the embodiment.

FIG. 3 is a schematic configuration diagram of a flow control valve device according to another embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a valve device according to still another embodiment of the present invention.

FIG. 5 is a graph showing a relationship between a loss coefficient of a butterfly valve and an opening ratio.

FIG. 6 is a graph showing a relationship between a loss coefficient of a gate valve and an opening ratio.

FIG. 7 is a graph showing a relationship between a cock valve and an opening ratio.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flow control valve apparatus 2 ... Pipe line 4 ... Butterfly valve 4a ... Divider valve 4b ... Cock valve 6, 6a ... Actuator 8 ... 1st pressure sensor 10 ... 2nd pressure sensor 12 ... Control means

Claims (10)

[Claims] A valve provided in the middle of a pipe through which a fluid flows; an actuator for changing an opening of the valve; an upstream static pressure of a pipe located upstream of the valve; A pressure sensor for measuring a pressure difference (ΔP) from a downstream static pressure of a pipe located downstream of the valve body, and a pressure difference (ΔP) detected by the pressure sensor.
From the equation shown below, the average flow velocity (U
m), and controlling the actuator to adjust the opening of the valve body so that the average flow velocity (Um) becomes a predetermined value. (Equation 1) 2. The pressure sensor according to claim 1, wherein the first pressure sensor is mounted on a wall of a pipe located upstream of the valve body, and the first pressure sensor is mounted on a wall of a pipe located downstream of the valve body. Second
The flow control valve device according to claim 1, further comprising a pressure sensor. 3. The method according to claim 1, wherein the cross-sectional reference dimension of the conduit is (D), and the first pressure sensor is 1 × D upstream of the valve body.
3. The flow control valve device according to claim 1, wherein the second pressure sensor is mounted at a position separated by 2 × D or more downstream of the valve body. 4. 4. The apparatus according to claim 1, wherein the first pressure sensor is mounted at a position 2.75 × D upstream of the valve body,
4. The flow control valve device according to claim 3, wherein the pressure sensor is mounted at a position of 4.33.times.D downstream of the valve body. 5. The flow control valve device according to claim 1, wherein the valve element is a butterfly valve, and an index (n) in the equation is about 1. 6. The flow control valve device according to claim 5, wherein the coefficient (C) in the equation is approximately 2.0 when the cross section of the conduit is circular. 7. The flow control valve device according to claim 5, wherein the coefficient (C) in the equation is approximately 1.7 when the cross section of the conduit is rectangular. 8. When the valve element is a gate valve and the cross-section of the pipe is circular, the index (n) in the equation is about 1.12, and the coefficient (C) in the equation is 5. The flow control valve device according to claim 1, wherein is equal to about 1.9. 9. The valve body is a gate valve, the cross section of the pipe is rectangular, and the opening ratio (β) is 0.1 or more and 0.3 or more.
In the following cases, the exponent (n) in the above equation is about 0.96
The flow control valve device according to any one of claims 1 to 4, wherein the coefficient (C) in the equation is approximately 2.5. 10. When the valve element is a gate valve, the cross section of the conduit is rectangular, and the opening ratio (β) is greater than 0.3 and 0.8 or less, an index ( The flow control valve device according to any one of claims 1 to 4, wherein n) is about 1.2, and a coefficient (C) in the equation is about 1.7.