JPH117323A - Flow control device - Google Patents

Abstract

(57) [Problem] To provide a flow rate control device capable of variably controlling the flow rate of a fluid from a small flow rate to a large flow rate over a wide flow rate range with a single pump. SOLUTION: A pump 2 is provided in a main pipe line 5a through which a fluid flows, and a flow meter 3 and a control valve 4 are provided at a position on the discharge port 11 side of the pump 2 in the main pipe line 5a. The opening degree of the control valve 4 is adjusted based on the measurement value detected by the control unit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a flow control device capable of controlling with high accuracy over a wide flow range from a small flow rate to a large flow rate.

[0002]

2. Description of the Related Art Conventionally, a pump is generally used as a means for sending a fluid to a pipeline while controlling the flow rate of the fluid.

[0003]

However, the above pump has a narrow controllable flow rate range, and even a gear pump which is considered to have the widest control flow rate range has a discharge ratio (ratio of the minimum controllable flow rate to the maximum controllable flow rate). The ratio is about 1:10, and it cannot be applied to fields and applications where the flow rate must be variably controlled with a wider range and higher accuracy.

On the other hand, in the field of dyeing textile products, in order to cope with the variety of designs, dye liquids in an extremely wide concentration range from a low concentration to a high concentration are adjusted with high precision and supplied. It is required to send the solution to a tank.However, conventionally, powder dyes are accurately weighed, and a plurality of the dyes are dissolved in a mixed state and individually adjusted to a dye solution having a desired concentration. It has been performed in a so-called batch system in which a supply tank is filled. However, in such a batch method, as the number of types and concentration variations of the adjustment dye liquid in multicolor dyeing increases, the time required for these liquid preparation operations becomes enormous, so from the viewpoint of production efficiency. Shortening of the time for the preparation of the dye solution has been an urgent issue.

Therefore, the development of an automatic dye solution preparation system is urgently required. As described above, a plurality of types of dye solutions ranging from a low concentration to a high concentration can be adjusted with high precision. It is required to supply liquid to each supply tank, but since the discharge ratio that can be controlled by one pump is at most about 1:10, let's construct a system that can handle such a wide concentration range. In this case, if a plurality of concentration areas are divided from low-concentration dying liquid to high-concentration liquor, and pumps are prepared individually corresponding to each concentration area, it can be theoretically constructed. 63-35
No. 873 discloses such a configuration,
However, the number of pumps required is the same as the number of required concentration areas, which not only increases equipment costs, but also requires a huge amount of equipment space for installing such a large number of pumps. It could not be a suitable system. Therefore, a device that can control the flow rate of the liquid over a wide flow rate range with one pump with high accuracy has been required.

The present invention has been made in view of such a technical background, and variably controls the flow rate of a fluid with a single pump over a wide flow rate range from a small flow rate to a large flow rate. It is an object of the present invention to provide a flow control device that can perform the control.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and as a result, provided a pump in a main line for sending a fluid, and provided a discharge port from the pump in the main line. A flow meter and a control valve are provided at the position on the side, and the opening of the control valve is adjusted based on the measurement value detected by the flow meter, so that the flow rate can be adjusted with high accuracy over a wide flow rate range. Has been found to be possible, and the present invention has been completed.

That is, a flow control device according to a first aspect of the present invention provides a main flow path having a suction port for taking in a fluid at one end and a discharge port for a fluid at the other end, and a predetermined discharge provided in the main flow path. A pump having a flow rate range, a flow meter and a control valve provided at a position closer to the discharge port than the pump in the main pipeline, and a control flow rate range of the control valve is higher than a predetermined discharge flow rate range of the pump. Also includes a flow rate range on the low flow rate side, and the opening of the control valve is adjusted based on the measurement value detected by the flow meter.

By adjusting the opening of only the pump with the control valve fully opened, the fluid is sent at a large flow rate while controlling the flow rate with high precision within the discharge flow rate range that can be controlled by the pump itself.
On the other hand, if the fluid once controlled to a low flow rate by the pump is further throttled by adjusting the opening of the control valve, a low flow rate far exceeding the lower limit area of the discharge flow rate range that can be controlled by the pump itself is achieved. Sends the fluid.

According to a second aspect of the present invention, there is provided a flow control device having a main pipe having a suction port for taking in fluid at one end and a fluid discharge port at the other end, and a predetermined discharge provided in the main pipe. A pump having a flow rate range, a bypass pipe branching from a position on the discharge port side of the pump in the main pipe to reach the discharge port, and a flow meter and a control valve provided in the bypass pipe, The control flow rate range of the control valve includes a flow rate range lower than the predetermined discharge flow rate range of the pump, and the opening of the control valve is adjusted based on the measurement value detected by the flow meter. It is characterized by being performed.

By adjusting the opening of only the pump using only the main conduit as the flow path, the fluid is sent at a large flow rate while controlling the flow rate with high precision within the discharge flow rate range that can be controlled by the pump itself. On the other hand, if the fluid once controlled to a low flow rate by the pump is sent to the bypass pipe and the opening of the control valve is adjusted to further control the throttle, the lower limit of the discharge flow rate range that can be controlled by the pump itself. The fluid is pumped at a low flow rate far beyond the area.

According to a third aspect of the present invention, there is provided the first or second aspect.
The flow control device of the above, which adopts a configuration in which a return line is provided for connecting a position from the pump to the flow meter in the line and a position of the main line on the suction port side with respect to the pump. It is.

[0013] Since the excess fluid due to the restriction of the control valve is returned to the main line again through the return line without being wasted, it is economical.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing the structure of a flow control device (1) according to the present invention. FIG. 2 (a) is an explanatory diagram showing a flow path when a fluid is sent at a large flow rate. (B) is an explanatory diagram showing a flow path when a fluid is sent at a small flow rate.

In these figures, (2) is a pump,
(3) is a bypass pipe flow meter, (4) is a control valve, (5)
Is a pipeline, and the pipeline (5) is composed of a main pipeline (5a), a bypass pipeline (5b), and a return pipeline (5c).

The main line (2a) has a suction port (10) for taking in fluid at one end and a discharge port (11) for fluid at the other end, and is provided on the side of the main line (2a) near the suction port (10). A pump (2) is provided at the position. As the pump (2), a positive displacement pump, particularly a gear pump, is preferably used because the discharge ratio is large and the precision is excellent.

Further, a main pipe flow meter (6) is provided in the main pipe (2a) at a position closer to the discharge port (11) than the pump (2). As the flow meter (6),
An electromagnetic flowmeter is preferably used because of its large rangeability and high accuracy. The measured flow value detected by the flow meter (6) is transmitted to the control device (20), and the control device (20) adjusts the discharge amount from the pump (2) based on the measured value. It has been done. The main line flow meter (6) is not necessarily provided, but is preferably provided from the viewpoint of further improving the accuracy of flow control.

A bypass line (5b) branches from a position on the discharge port (11) side of the main line flow meter (6) in the main line (2a).
2) is provided, while the other end of the bypass pipe (5b) merges with the main pipe (2a) just before reaching the discharge port (11). By the switching of the switching valve (12), the fluid that has passed through the pump (2) and has flowed through the main pipeline (2a) and has reached the branch portion is directly passed through the main pipeline (2).
A choice is made between the flow to a) and the flow to the bypass line (5b). The switching of the switching valve (12) is controlled by the control device (20). It has been done.

The bypass pipe (5b) is provided with a bypass pipe flow meter (3) and a control valve (4).

As the bypass pipe flow meter (3), an electromagnetic flow meter is preferably used because of its large rangeability and excellent accuracy. Then, the measured flow value detected by the flow meter (3) is transmitted to the control device (20), and the opening of the control valve (4) is adjusted by the control device (20) based on the measured value. It has been made to be done.

As the control valve (4), a valve capable of controlling at least a flow rate range lower than the controllable discharge flow rate range of the pump (2) is used. At this time, the lower limit area of the controllable discharge flow rate range of the pump (2) and the upper limit area of the controllable flow rate range of the control valve (4) are as shown in FIG.
The pump (2) is set so as to partially overlap as shown in (a), or as shown in FIG.
And the controllable upper limit value of the control valve (4) are preferably set so as to substantially coincide with each other. With this setting, there is no uncontrollable region between the controllable flow rate range of the pump (2) and the controllable flow rate range of the control valve (4). It is possible to perform variable control with high accuracy over a wide flow rate range without the presence of an uncontrollable region. Of course, the overlap area of the controllable flow rate ranges of the pump (2) and the control valve (4) may be made larger than the overlap area shown in FIG.
In this case, the flow rate range in which variable control can be performed with high precision is reduced as compared with the former.

Further, the position of the bypass line (5b) on the suction port (10) side from the flow meter (3), and the position of the main line (2a) on the suction port (10) side of the pump (2). And a return conduit (5c) is provided in a manner to connect the two. When returning fluid to the bypass pipeline (5b), the return pipeline (5c) supplies excess fluid due to flow control by the control valve (4) to the pump (2) in the main pipeline (2a). ) Suction port (1)
At the position on the 0) side, the fluid supplied from the suction port (10) is merged and returned to the main pipeline (2a) again so that the fluid is effectively used without wasting. It is.

The return pipe (5c) is provided with a needle valve (13) for opening and closing the flow path of the return pipe (5c). The needle valve (13) is connected to the control device (20)
The needle valve (13) is closed so that the fluid does not flow back to the return line (5c) when the fluid flows only through the main line (2a). It has been made like that.

Thus, the flow control device (1) having the above configuration
When sending a fluid while controlling its flow rate by using a controller, a desired flow rate value or a flow rate setting program is input to the controller (20) in advance. The control device (20)
Whether the set flow rate is in a large flow rate range in which the flow rate can be controlled only by the pump (2) or in a small flow rate range in which the flow rate can be controlled by the cooperation of the pump (2) and the control valve (4) In the former case, the switching is performed so that the switching valve (12) communicates with the main line (2a), while in the latter case, the switching valve (12) is switched so as to communicate with the bypass line (5b). Switching is performed.

FIG. 2A is a diagram showing a flow path when a fluid is sent at a large flow rate. As described above, the control device (20) controls the switching of the switching valve (12) so as to communicate with the main line (2a), while closing the needle valve (13) disposed in the return line (5c). . Accordingly, the fluid sucked in from the suction port (10) by driving the pump (2) flows through only the main pipe (2a) and is discharged from the discharge port (11) as shown in FIG. . At this time, the flow rate sent by the pump (2) is monitored one by one by the main pipeline flow meter (6), and when the monitored flow rate value deviates from a desired flow rate value, the control device is controlled. Since the opening of the pump (2) is adjusted by the signal from (20), the fluid can be sent at a large flow rate while always controlling the flow rate with high accuracy.

On the other hand, FIG. 2B is a view showing a flow path when a fluid is sent at a small flow rate. The control device (20) controls switching of the switching valve (12) so as to communicate with the bypass line (5b), while setting the needle valve (13) disposed in the return line (5c) to a fully open state. Is done. The controller (20) adjusts the opening degree of the pump (2) so as to have a minimum flow rate or a low flow rate within a range that can be controlled with high precision, while the control valve (4) adjusts the discharge flow rate to a desired value. The opening is adjusted based on the correlation with the opening of the pump (2) so that the flow rate value of the pump (2) is obtained. Accordingly, the fluid sucked from the suction port (10) by driving the pump (2) flows through the main pipeline (2a) and reaches the switching valve (12) as shown in FIG. Flows into the bypass pipe (5b) through the control valve (4), and then flows through the bypass pipe (5b).
Discharged from 1). At this time, the flow rate sent through the bypass pipe (5b) is monitored one by one by the bypass pipe flow meter (3), and when the monitored flow value deviates from a desired flow value. Is the control unit (2
Since the opening of the control valve (4) is adjusted by the signal from 0), the fluid can be sent at a small flow rate while always performing the flow control with high accuracy.

The excess fluid due to the narrowing of the control valve (4) flows through the return pipe (5c), and the main pipe (2a) is located closer to the suction port (10) than the pump (2) is installed. At the position, the fluid merges with the fluid supplied from the suction port (10). By providing such a return pipe (5c),
The main pipeline (2
It is possible to return to a), which is economical.

According to the flow control device (1) of the present invention, when a fluid is sent at a large flow rate, the main pipeline (2a)
By setting only the flow path as the flow path and adjusting the opening of only the pump (2), it is possible to send a large flow rate while controlling the flow rate with high precision within the range of the discharge flow rate which can be controlled by the pump (2). .

On the other hand, when the fluid is sent at a small flow rate,
The fluid once controlled at a low flow rate by the pump (2) is sent to the bypass pipe (5b), and the opening of the control valve (4) is further adjusted in the bypass pipe (5b). Furthermore, since the discharge is performed by controlling the narrowing down, the pump (2)
The flow can be sent at a low flow rate far exceeding the lower limit area of the original controllable discharge flow rate range.

Thus, the flow control device (1) of the present invention
According to this, with a single pump, from a high flow rate corresponding to the upper limit area of the controllable discharge flow rate range of the pump (2) itself to a small flow rate corresponding to the lower limit area of the controllable flow rate range of the control valve (4). It is possible to control the flow rate with high accuracy up to that point. Further, since it is not necessary to equip a plurality of pumps, low cost and equipment space can be achieved.

The flow rate control device of the present invention can variably control the flow rate with high accuracy over a wide flow rate range from a small flow rate to a large flow rate as described above. It is suitably used for adjustment of.

That is, as a dye solution for dyeing textiles, a dye solution having an extremely wide concentration range from a low concentration to a high concentration is adjusted with high precision in order to cope with the variety of designs. Although it is required to feed the solution to each supply tank, if the flow rate control device (1) of the present invention is incorporated in the dye stock solution supply pipe (32) of the solution preparation system as shown in FIG. 3, the dye stock solution (30) Is controlled with high precision over a wide flow rate range from a small flow rate to a large flow rate, and supplied to a main supply pipe (33) to which a constant flow rate of water (31) is supplied via a dye stock solution supply pipe (32). As a result, a single dye stock solution (30) can be used to adjust and supply a dye solution in a very wide concentration range from a low concentration to a high concentration using a single dye stock solution (30). Become. The supply water is controlled at a constant flow rate by cooperation of the pump (34), the flow meter (35), and the control device (36).

The bypass line (5b) of the flow control device of the present invention may be further provided with a second bypass line (5d). That is, as shown in FIG. 4, for example, the second switching valve (5) is located at a position closer to the discharge port than the position where the bypass line flow meter (3) and the control valve (4) are provided. The second bypass pipe (5d) is branched via 12d), and the second bypass pipe (5d) is provided with a second bypass pipe flow meter (3d) and a second bypass pipe control valve (4d). The other end of the second bypass pipe (5d) joins the main pipe (5a) before the discharge port (11), and
The second needle valve (1) is connected to a position of the bypass line (5d) closer to the suction port (10) than the second bypass line flow meter (3d) and the return line (5c).
A second return line (5e) with 3d) is provided. As described above, the bypass pipeline is configured in two stages, that is, the fluid controlled at a low flow rate by the bypass pipeline (5b) is sent to the second bypass pipeline (5d), and the second bypass pipeline (5d) is sent. Since it is possible to further narrow down the flow rate by the second bypass pipe adjusting valve (4d) of (5d), a wider flow rate than that in which the bypass pipe (5b) described above is constituted by one stage is used. The flow rate can be variably controlled with high accuracy over a range.

Of course, a third bypass line may be provided for the second bypass line in the same manner as described above. Thus, the flow rate can be variably controlled with high accuracy over a wider flow rate range.

[0036]

Next, specific embodiments of the present invention will be described.

<Embodiment 1> The flow rate of the dye stock solution was controlled using the flow rate control device having the structure shown in FIG. That is, the inlet of the main conduit of the flow control device is connected to the bottom of the dye stock tank in which the stock solution is stored,
In the case where the actual flow rate when each of the dye stock solutions is sent for 1 hour and the actual flow rate is sent at a large flow rate (2 to 20 L / min) is set by setting each set flow rate shown in Table 1 and driving the flow rate control device. The flow value output from the main pipeline flow meter is output via the A / D conversion board.
Monitor with a personal computer, process and record the data. On the other hand, when sending at a small flow rate (0.2 to 2 L / min), output the flow rate value from the bypass pipe flow meter via the A / D conversion board. The data was monitored and monitored on a personal computer. From these, the maximum value of the fluctuation rate of the actual flow rate ((actual flow rate−set flow rate) ÷ set flow rate × 100) was determined. Table 1 shows the results.

A gear pump (controllable flow rate range: 2 to 20 L / min) is used as a pump constituting the flow rate control device, and a control valve manufactured by Yamatake Honeywell (control valve: model number HLS ACT.HA1R, single acting) is used as a control valve. Model HEP electric-pneumatic valve positioner: Model number HEP15-114
The controllable flow rate range of 0.2 to 2 L / min) is set as an electromagnetic flow meter (detectable flow rate range of 0.2 to 2
L / min), an electromagnetic flowmeter (detectable flow rate range of 2 to 20 L / min) was used as the main pipeline flowmeter.

When the fluid was sent at a large flow rate (2 to 20 L / min), only the main conduit was used as a flow channel by switching the switching valve. On the other hand, a small amount of fluid (0.2 to
(2 L / min), the switching valve switches to use a flow path from the main line to the bypass line, and the opening degree of the gear pump is 2 in any case.
L / min.

[0040]

[Table 1]

<Comparative Example 1> One pipe (101) and the pipe
The flow rate of the undiluted dye solution was controlled using a flow rate control device (100) having the configuration shown in FIG. 6 and comprising a pump (102) provided in (101). That is, the suction port (103) of the pipe of the flow rate control device (100) is connected to the bottom of the dye stock solution tank in which the stock solution is stored. 100) is driven, and the actual flow rate when each of the dye stock solutions is sent for one hour is calculated by the discharge port (1
04) Using a flow meter provided on the side, monitoring was performed by a personal computer in the same manner as in Example 1, and data processing and recording were performed. And
From these, the maximum value of the fluctuation rate of the actual flow rate was obtained. Table 2 shows the results. The same gear pump as that used in Example 1 was used as the pump.

[0042]

[Table 2]

<Evaluation Results> As is apparent from Table 1, according to the flow rate control device of the first embodiment of the present invention, 0.2 to 2
The maximum fluctuation rate is within approximately ± 0.5% over a wide flow rate range of 0 L / min, and the dye stock solution can be sent over the wide flow rate range while controlling the flow rate with extremely high precision.

On the other hand, in the flow control device of Comparative Example 1, which deviates from the scope of the present invention, the maximum fluctuation rate is large in the small flow rate range of 0.2 to 2 L / min, and the accuracy of flow control is deteriorated. However, in such a wide flow rate range of 0.2 to 20 L / min, it was not possible to precisely control the flow rate and feed the dye stock solution.

[0045]

According to the first aspect of the present invention, the control valve is fully opened to adjust the opening of only the pump, thereby controlling the flow rate with high precision within the discharge flow rate range of the pump itself, and allowing the fluid to flow at a large flow rate. While it is possible to send the fluid, once the flow is controlled to a low flow rate by the pump and the throttle is controlled by further adjusting the opening of the control valve, it far exceeds the lower limit area of the discharge flow rate range of the pump itself. The fluid can be sent at a low flow rate. As described above, the flow rate can be variably controlled with high accuracy over a wide flow rate range from a small flow rate to a large flow rate, and this can be achieved by a single pump, and it is necessary to equip a plurality of pumps. Therefore, low cost and equipment space can be saved.

According to the second aspect of the present invention, only the main pipeline is used as a flow path, and only the pump is adjusted in the degree of opening. On the other hand, the fluid once controlled to a low flow rate by the pump is sent to the bypass pipe line, and by further controlling the aperture by adjusting the opening of the control valve,
The flow can be sent at a low flow rate far exceeding the lower limit area of the original discharge flow rate range of the pump. As described above, the flow rate can be variably controlled with high accuracy over a wide flow rate range from a small flow rate to a large flow rate, and this can be achieved by a single pump, and it is necessary to equip a plurality of pumps. Therefore, low cost and equipment space can be saved.

According to the third aspect of the present invention, the excess fluid due to the narrowing of the control valve can be returned to the main pipeline again through the return pipeline without being wasted, so that the fluid can be economically used. Can be sent.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing a fluid flow path, and FIG.
FIG. 3B shows a case where the flow is sent at a large flow rate, and FIG. 6B shows a case where the flow is sent at a small flow rate.

FIG. 3 is a system diagram showing an example of a configuration of an automatic liquid preparation system.

FIG. 4 is a system diagram showing a configuration of a flow control device according to another embodiment.

FIG. 5 is an explanatory diagram showing an example of a relative relationship between a discharge flow rate range of a pump and a control flow rate range of a regulating valve.

FIG. 6 is a system diagram showing a configuration of a flow control device according to a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flow control device 2 ... Pump 3 ... Flow meter 4 ... Control valve 5 ... Pipe 5a ... Main pipe 5b ... Bypass pipe 5c ... Return pipe 10 ... Suction port 11 ... Discharge port

Claims (3)

[Claims] 1. A main pipe having a suction port for taking in fluid at one end and a discharge port for fluid at the other end, a pump provided in the main pipe and having a predetermined discharge flow rate range, and A flow meter and a control valve provided at a position closer to the discharge port than the pump, wherein the control flow rate range of the control valve includes a flow rate range lower than a predetermined discharge flow rate range of the pump. ,
A flow control device, wherein an opening of a control valve is adjusted based on a measurement value detected by the flow meter. 2. A main pipe having a suction port for taking in a fluid at one end and a fluid discharge port at the other end, a pump provided in the main pipe and having a predetermined discharge flow rate range, and A bypass pipe branching from a position on the discharge port side of the pump to the discharge port, and a flow meter and a control valve provided in the bypass pipe, and the control flow rate range of the control valve is the pump While including a flow rate range on the lower flow rate side than the predetermined discharge flow rate range,
A flow control device, wherein an opening of a control valve is adjusted based on a measurement value detected by the flow meter. 3. A return pipe is provided for communicating a position in the pipe from the pump to the flow meter and a position of the main pipe closer to the suction port than the pump. 3. The flow control device according to 2.