JPH04198818A - Flow measuring system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) This invention relates to a system for transporting a liquid fluid (which may contain solids) using reduced pressure (including a vacuum). The present invention relates to a flow rate measurement system that measures the flow rate of liquid fluid.

(Prior Art) FIG. 6 shows an example of the configuration of a conventional plant for transferring a stock solution 2 made of concentrated black liquor, which is a type of highly viscous fluid. The thick black liquor is a liquid obtained by vacuum evaporating and concentrating the liquid after cooking wood chips (dilute black liquor) in a valve plant. In FIG. 6, a first device 1 is a device for preparing a stock solution 2. In FIG. This stock solution 2 is a viscous, black liquid containing caustic soda such as cellulose, glinin, mannan, and starch. Equipment W1
is connected via a valve 4 to a vacuum device 10 by a pipe system 12. When the pressure inside the vacuum device 10 is reduced by the vacuum pump 8 and the valve 4 is opened, the stock solution 2 flows from the device 1 into the vacuum device 10 due to the pressure difference. The stock solution 2 in the vacuum device 10 is stirred together with the reactive gas, chemicals, etc. supplied from the transfer pipe 7 by the stirring device 9. A discharge device 11 for discharging the product is arranged at the lower end of the vacuum chamber WL10.

(Problem to be Solved by the Invention) In the configuration shown in FIG. 6, since the pressure inside the vacuum device 10 is reduced, the gas dissolved in the stock solution 2 boils in the pipe system 12, and the volume of the stock solution 2 decreases. increase

For this reason, for example, even if a flow meter is installed in the pipe system 12, the flow rate of the stock solution 2 cannot be accurately measured, resulting in a large error in the measured value.

This invention was made in view of the above circumstances, and its purpose is to provide a flow rate measurement system that can relatively accurately measure the flow rate of liquid fluid flowing through a pipe system connected to a storage device such as a reduced pressure vacuum device. It is to be.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a flow rate measurement system according to a first aspect of the invention includes a first device and a second device set in a reduced pressure state. an apparatus, a pipe system for transferring liquid fluid from the first apparatus to the second apparatus by utilizing the reduced pressure state of the second apparatus, and a pipe system located at a position where almost no gas is generated in the pipe system. Built-in flow measuring bag device,
Equipped with

A flow measurement system according to a second aspect of the present invention includes a first device, a second device set in a reduced pressure state, and a flow measurement system that uses the first device to a pipe system for transferring liquid fluid from the device to the second device; a flow rate measuring device disposed in the pipe system; a resistance part that provides resistance to the flow of the liquid fluid;
Equipped with

A flow rate measurement system according to a third aspect of the present invention includes a first device, a second device set in a reduced pressure state, and a flow measurement system that uses the second device set in a reduced pressure state to A pipe system for conveying the liquid fluid from the device to the second device, a flow rate measuring device disposed in the pipe system, and an evaluation device for evaluating the amount of the fluid to be measured remaining in the pipe system. and determining the flow rate of the liquid fluid flowing into the second device based on the measured value of the flow rate measurement device and the evaluation value of the evaluation device.

(Function) In the flow measurement system according to the first aspect of the invention,
Since the second device is set at reduced pressure, the pressure difference between the first and second devices causes liquid fluid to be conveyed from the first device to the second device through the pipe system. Since the second device is set to a reduced pressure state, the gas dissolved in the liquid fluid within the pipe system boils and generates (or tends to generate). However, since the flow meter is installed in a position where almost no gas is generated, it is hardly affected by the gas generated and can measure the flow rate relatively accurately.

In the flow measurement system according to the second aspect of the invention,
When the liquid fluid is conveyed from the first device to the second device,
Gas is generated within the pipe system. However, the second
Since the resistance section is arranged on the side of the first device, the pressure near the flow meter is relatively close to the pressure of the first device, making it difficult for gas to be generated.

Therefore, the measured value is not significantly affected by the generated gas, and the flow rate can be measured relatively accurately.

In the flow measurement system according to the third aspect of the invention,
When the liquid fluid is conveyed from the first device to the second device,
Gas is generated within the pipe system. However, since the evaluation device evaluates the remaining volume of liquid fluid in the pipe system, it is relatively accurate by using the measured value of the flowmeter and the evaluation value of the evaluation device, taking into account the remaining amount in the pipe system. flow rate can be measured.

(Embodiment) Hereinafter, the structure of a flow rate measuring system according to an embodiment of the present invention will be described with reference to FIG.

Figure 1 shows stock solution 2 consisting of concentrated black liquor, a type of highly viscous fluid.
1 shows a system for transferring the liquid from a storage device 1 to a vacuum device 2 using a vacuum. That is, the device 1 is connected to a vacuum device 10 by a pipe system 12. The pipe system 12 includes a flow meter 3 installed near the inlet of the pipe system 12, a first valve 4 placed closer to the vacuum device than the flow meter 3, a second valve 6 installed near the outlet of the pipe system 12, First and second valves4.
An evaluation device 5 is provided between the two. The flowmeter 3 is composed of, for example, an electromagnetic flowmeter, an ultrasonic flowmeter, or the like. The first and second valves 4.6 are opened and closed, for example, in order to input the stock solution 2 periodically or in batches as needed from the device 1 constituted by an electromagnetic valve to the vacuum device 10.

A vacuum pump 8 and a transfer pipe 7 for introducing reactive gases, chemicals, etc. into the vacuum device 10 are connected to the top of the vacuum device 10 . A stirring device 9 is attached to the vacuum device 10. At the lower end of the vacuum device 10, a discharge device 11 for discharging the product is arranged.

Next, the operation of the flow rate measurement system shown in FIG. 1 will be explained.

When transferring the stock solution 2 from the device 1 to the vacuum device 10, the inside of the vacuum device 10 is set to a reduced pressure state by the vacuum pump 8. When the degree of vacuum within the vacuum device 10 reaches a desired level,
The first and second valves 4.6 are opened. Due to the difference between the reduced pressure in the vacuum device 10 and the atmospheric pressure, the stock solution 2 in the device 1
is transferred to the vacuum device 10 via a pipe system 12. Since the stock solution 2 has viscosity, the flow velocity in the pipe is generally 0.5 m/
It is about s.

When the stock solution 2 is transferred from the device 1 to the vacuum device 10, the pressure inside the vacuum device 10 is reduced, so that the gas dissolved in the stock solution 2 is boiled and generated. The amount of gas generated is determined by pipe system 1.
It is almost zero near the inlet of the vacuum chamber [10], increases as the pressure inside the pipe system 12 becomes lower, and is the largest near the inlet of the vacuum system [10].

Since the flow meter 3 is installed near the inlet of the pipe system 12, that is, in a position where almost no gas is generated, the flow rate measurement is hardly affected by the generated gas, and the flow rate of the stock solution 2 can be accurately measured. .

When the first and second valves 4.6 are closed, the transfer of the stock solution 2 from the device 1 to the vacuum device 10 is stopped.

The amount of stock solution 2 introduced into the vacuum device 10 is the amount obtained by subtracting the amount of stock solution 2 remaining in the pipe system 12 from the measurement value of the flowmeter 3. Since the generated gas is present in the pipe system 12, the volume of the residual stock solution 2 does not necessarily match the volume of the pipe system 12.

Therefore, the evaluation device 5 evaluates (detects, calculates, predicts, etc.) the amount of the remaining stock solution 2 in the pipe system 12. By subtracting the residual fluid amount determined by the evaluation device 5 from the flow rate determined by the flow meter 3, the amount of the stock solution 2 in the vacuum device 10 can be determined. (In the initial state, the pipe system 12 is
The amount of stock solution 2 in the vacuum device 10 can be determined by subtracting the residual fluid amount determined by the evaluation device 5 from the sum of the flow rate determined by the flow meter 3 and the volume of the pipe system 12. good).

Corresponding to the determined amount of the stock solution 2 in the vacuum device 10, a required amount of chemicals and the like is introduced from the transfer pipe 7 and stirred by the stirring device 9. The product is discharged by a discharge device 11.

Thereafter, the stock solution 2 is replenished from the device 1 to the vacuum device 10 periodically or in batches as needed.

Next, an example of the configuration of the evaluation device 5 will be explained with reference to FIGS. 2 and 3.

In the second step, when the gas injection device 21 (which may be an atmosphere release valve, compressed air cylinder, gas cylinder, etc.) has the first and second valves 4.6 closed and the valve 22 opened, When the pressure within the pipe system 12 reaches a predetermined value (for example, 1
Gas is injected into the pipe system 12 until the pressure reaches (atmospheric pressure). Gas flow meter 23 measures the amount of gas injected into pipe system 12 .

The volume of the gas portion within the pipe system 12 can be measured from the measured value of the gas flow meter 23. By subtracting the volume of the gas portion from the volume of the pipe system 12, the amount of residual stock solution 2 in the pipe system 12 can be determined.

FIG. 3 shows another example of the evaluation device. The table 31 stores the amount of remaining stock solution determined in advance through experiments for each combination of the type of stock solution, the pressure of the device 1, and the pressure inside the vacuum device 10. Pressure gauge 3 attached to device 1 and vacuum device 10
Based on the pressure data from 2.33 and the data indicating the type of stock solution 2 input from the keyboard 34 etc., the table 31
The data within is specified and output as an evaluation value. With this configuration, an evaluation device does not have to be provided in the pipe system 12.

The amount of the remaining stock solution 2 may be measured by inserting a sensor into the pipe system 12 or by detecting the position of the upper surface of the remaining stock solution using an optical laser sensor, an ultrasonic sensor, or the like.

If the transfer of the stock solution 2 from the device 1 to the vacuum device 10 is repeated under the same conditions, the amount of the stock solution 2 remaining in the pipe system 12 is taken into consideration only the first time, and there is no need to take it into account thereafter. (This is because when the stock solution 2 remaining in the pipe system 12 is carried into the vacuum device 10, the same amount of stock solution 2 remains in the pipe system 12). In addition, if the volume of the pipe system 12 is relatively small and can be ignored, the evaluation device 5
is not necessary.

Furthermore, when transferring the stock solution to the vacuum device 10, there are cases in which it is sufficient to input a value near the target value A (A±α) into the vacuum device 10, and there are cases in which it is necessary to input the target value A accurately. .

If it is sufficient to input a value close to the target value A into the vacuum apparatus 10, there is no need to strictly regulate the input flow rate. Therefore, for example, when the measured value of the flowmeter 3 reaches the vicinity of the target value A, the valve 4.6 is closed, and the flow rate actually input to the vacuum device 10 is determined from the evaluation value of the evaluation device 5. The amount of chemicals or gas to be introduced into the vacuum device 10 from the transfer pipe 7 may be adjusted according to the amount actually introduced. The amount of this chemical, etc. may be automatically adjusted in conjunction with the output of the evaluation device 5.

On the other hand, when it is necessary to input the amount exactly to the target value into the vacuum apparatus 10, the input flow rate must be strictly regulated. Therefore, in advance, the transfer of the stock solution 2 is stopped within a range where the amount of the stock solution 2 charged into the vacuum device 10 does not exceed the target value, and the flow rate charged into the vacuum device 10 is determined from the evaluation value of the evaluation device 5. Then, the difference between the determined actual inflow amount and the target value A may be input into the vacuum device 10 by, for example, an auxiliary device provided in the vacuum device 2.

In this way, the target value A can be accurately input into the vacuum device 10. Since this auxiliary device only needs to inject a relatively small amount of stock solution into the vacuum device 10, its configuration is simple, and its flow rate, weight, etc. can be measured relatively accurately.

Note that although the expression undiluted solution is used, it may be a slurry fluid containing solids.

In the embodiment described above, the flow meter 3 was placed near the inlet of the device 1 of the pipe system 12. This is because near the device 1, the liquid pressure is approximately atmospheric pressure, the amount of gas generated from the stock solution 2 is almost zero, and the flow rate of the stock solution 2 being transported can be measured relatively accurately. However, this invention is not limited to this. For example, as shown in FIG. 4, when a constrictor tube 41 is arranged in the pipe system 12, the fluid resistance (pressure loss) at the constrictor tube 41 is large, and gas and bubbles are generated on the device 1 side of the constrictor tube 41. is less likely to occur. In such a case, the flow meter 3 does not necessarily need to be placed near the device 1. This effect can also be obtained, for example, by adjusting the opening degrees of the first and second valves 4.6. Furthermore, when the stock solution 2 is a viscous fluid, a pipe system 12 without a throttle as shown in FIG. 5 can sufficiently produce the same effect as a throttle pipe.

In the above embodiment, the concentrated black liquor is transferred from the device 1 to the vacuum device W1.
The present invention will be described using an example of a system for transferring data to 0, but the present invention is not limited to the above embodiment.

The object to be transferred, that is, the object to be measured in flow rate may be other viscous liquids, such as water-soluble plastics, sugar concentrate (magma), chemicals, and sewage. For example, when the object to be transported is a raw sugar solution, the device 1 is a magma adjustment device, the vacuum device 10 is a crystallization can, and the precipitate (sugar crystals) in the crystallization can is discharged by the discharge device 11.

The present invention is not limited to the above-mentioned embodiments, but can also be applied, for example, to the case of transporting liquid between devices. That is, it has wide application in flow measurement in systems where gas is generated during the transfer of liquids (which may include solids) from one storage device to another.

[Effects of the Invention] According to the present invention, the flow rate can be accurately measured because the flow meter is placed in a position where bubbles are unlikely to be generated. Also,
Since the resistance section is placed on the reduced pressure side of the flowmeter, the generation of bubbles near the flowmeter can be suppressed and the flow rate can be measured accurately. Further, by providing the evaluation device, it is possible to evaluate the amount of the fluid to be measured remaining in the pipe system, and it is possible to accurately specify the flow rate of the fluid to be measured that has flowed into the second device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a flow rate measurement system according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing an example of the configuration of an evaluation device, and FIGS. 4 and 5 are diagrams showing a pipe system. FIG. 6 is a diagram showing an example of the configuration of a conventional flow rate measuring system. 1... Device, 2... Stock solution, 3... Flow meter, 4.6
．． 22... Valve, 5... Evaluation device, 7... Transfer tube, 8... Vacuum pump, 9... Stirring device, 10...
・Vacuum device, 11... Discharge device, 12... Pipe system, 21... Gas injection device, 23... Gas flow meter, 2
4.32.33...pressure gauge, 31...table,
34...Keyboard, 41...Aperture section. Figure 1 Figure 3 Figure 6

Claims (3)

[Claims] (1) a first device that contains a liquid fluid; a second device that is set to a reduced pressure state and contains the liquid fluid; and a device that connects the first device and the second device, and a second device that contains the liquid fluid; a pipe system that transfers the liquid fluid from the first device to the second device by utilizing a reduced pressure state; and in the pipe system, the liquid fluid is transferred from the first device to the second device. A flow rate measurement system comprising: a flow rate measurement device incorporated in a position where little gas dissolved in the liquid fluid is generated. (2) a first device that contains a liquid fluid; a second device that is set to a reduced pressure state and that contains the liquid fluid; and a second device that connects the first device and the second device; a pipe system that conveys the liquid fluid from the first device to the second device by utilizing the fact that the device is in a reduced pressure state; a flow rate measuring device disposed in the pipe system; A flow rate measurement system comprising: a resistance section that is disposed on the second device side and provides resistance to the flow of the liquid fluid within the pipe system. (3) a first device that contains a liquid fluid; a second device that is set to a reduced pressure state and that contains the liquid fluid; and a second device that connects the first device and the second device; a pipe system that conveys the liquid fluid from the first device to the second device by utilizing the reduced pressure state; a flow rate measuring device disposed in the pipe system; and a flow rate measuring device disposed in the pipe system; an evaluation device for evaluating the amount of fluid to be measured that is flowing into the second device, and a flow rate for determining the flow rate of the liquid fluid flowing into the second device based on the measurement value of the flow rate measurement device and the evaluation value of the evaluation device. measurement system.