JPH0552632A - Delivery volume speed reducing type liquid measuring method and device used therefor - Google Patents

Abstract

PURPOSE:To accurately measure volume of a high viscous liquid by flowing out the liquid by means of a constant volume pump, decreasing gradually the number of revolutions of the constant volume pump when outflow volume reaches a boundary volume of prescribed throttling, and taking out a necessary volume of the liquid by stopping the rotation. CONSTITUTION:A pipe conduit 1 connects a liquid A storage tank T with a delivery port 11 provided with a solenoid valve, and a constant volume pump 2 and a mass flowmeter 3 are arranged in the middle of the pipe conduit. A microprocessor-using control means 4 is connected to the flowmeter 3, the pump 2 and a driving motor 21. Furthermore, when a necessary volume X of the liquid A is set in the control means 4, the control means 4 opens the solenoid valve, and rotates the motor 21 at the prescribed number of revolutions R(F) determined by a liquid filling volume F. When the filling volume F reaches a boundary volume of throttling, the motor is decelerated at constant deceleration, and when the filling volume F reaches the necessary volume X, the rotation is stopped completely. Thereby, even high viscous liquid can be measured accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid measuring method and a device used for the same which can measure more accurately than conventional methods.

[0002]

2. Description of the Related Art In the production of almost any product, there is always exactly one optimum condition for its production. Then, it is desirable that all the same products are always produced under predetermined optimum conditions.

For example, in the case of a production process including a chemical reaction,
The reaction rate and economic efficiency vary depending on the concentration conditions of each reaction solution and each enzyme during the chemical reaction. Therefore, it is important to mix each reaction solution in an appropriate amount and to control the concentration condition accurately to the optimum condition.

However, in the current measurement of reaction liquids, at first, the liquid is allowed to flow out at high speed, and when the required amount is about to be reached, a small-diameter bypass pipe or the like is used to suddenly reduce the outflow rate so that the amount near the required amount is reached. Since the method of closing the valve and stopping the outflow is adopted, there is a drawback that an error may occur due to deviation of the valve closing timing, and when measuring a viscous liquid, slowing down the outflow speed will make the speed constant. There was also a problem that accurate measurement could not be performed.

[0005]

Therefore, it is a technical object of the present invention to accurately measure a liquid having a high viscosity.

[0006]

In the present invention, a required amount of a desired liquid is set, the liquid is caused to flow out from a discharge port by a constant volume pump through a predetermined pipe line, and the difference between the set amount and the liquid outflow amount. When the constant volume pump stops rotating, the liquid outflow rate becomes equal to the set amount when the constant volume pump stops rotating, and the desired liquid is discharged from the discharge port. By adopting a means for taking out a fixed amount, a weighing method for solving the above-mentioned problems was provided.

Further, the storage means and the discharge port are connected by a pipe, a constant volume pump is provided in the middle of the pipe, the amount of the liquid flowing out from the pipe is measured by the measuring means, and the control means is provided as described above. By providing a means for connecting the constant volume pump and the measuring means, and causing the control means to control the rotation of the constant volume pump based on the measurement information of the measuring means, the measuring device used for the above-mentioned measuring method is provided.

[0008]

EXAMPLES The present invention will be described below based on examples.

A line 1 connects a storage tank T for the liquid A to a discharge port 11 equipped with an electromagnetic valve. A constant volume pump 2 and a mass flowmeter 3 are provided in the middle of the pipe line 1. Further, the mass flow meter 3 and the power motor 21 of the constant volume pump 2 are connected to a control means 4 employing a microprocessor.

First, the container P is placed under the discharge port 11 and the required amount X of the liquid A is set in the control means 4. Then, the control means 4 opens the electromagnetic valve and rotates the power motor at a predetermined rotation speed R (F) determined by the liquid filling amount F until then. Then, when R (F) = 0 finally, the electromagnetic valve is closed to complete the filling. However, R (F) is given by the following equation.

[0011]

[Formula 1]

That is, the power motor 21 has a rotation speed of 0 rpm.
To the maximum number of revolutions R _max rpm with uniform acceleration,
After that, it rotates at a constant speed at R _max rpm, but when the accumulated filling amount F accompanying the driving of the pump 2 reaches a certain value A (narrowing boundary amount), from R _max rpm to the minimum rotation speed R _min rpm, etc. After decelerating with acceleration and rotating at a constant rotational speed of R _min rpm for a while, the rotation is completely stopped when F = X. However, the narrowing boundary amount A is given by the following equation.

[0013]

[Formula 2]

By the control as described above, the container P can be accurately filled in a fixed amount. R _max = 400,
When R _min = 40, when X = 20 kg and when X = 2 kg
The following table shows the actual filling amount when the setting was set to.

[0015]

[Table 1]

In this embodiment, the liquid filling amount F
Is a mass flowmeter 3 each time 0.0001 kg of liquid flows in the pipeline.
Oscillates one pulse to the control means 4 and is observed by integrating the pulse by the control means. The constant G,
The maximum rotation speed and the minimum rotation speed of the power motor 21 may be variously selected depending on the type of liquid.

Although the present embodiment is as described above, the present invention is not limited to the above embodiment. For example, instead of a mass flow meter as a measuring means for measuring the amount of liquid flowing out from a pipe, An electronic balance provided under the container may be adopted, or a means for estimating the outflow amount by counting the rotation of the constant volume pump may be adopted.

[0018]

According to the above method, the flow rate of the liquid can be completely controlled by the rotation of the constant volume pump, and further, the rotation of the constant volume pump is slowed while the flow rate is controlled, and the outflow of the desired liquid is narrowed and measured. Since it is designed to be completed, there is no need for prospective blockage of the valve, and accurate metering is possible. Further, even when measuring a highly viscous liquid, the constant volume pump guarantees a stable flow and accurate measurement can be performed. Therefore, the method of the present invention has high industrial utility value, and the apparatus used therefor is also the same.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment.

FIG. 2 is a chart diagram illustrating filling control of the apparatus according to the embodiment.

FIG. 3 is a graph showing changes in the liquid outflow amount per unit time when the liquid is measured by the method of the embodiment.

[Explanation of Codes] 1 Pipeline 2 Constant Volume Pump 3 Mass Flowmeter 4 Control Means

Claims (5)

[Claims] 1. A required amount of a desired liquid is set, and when the set amount is equal to or more than a narrowing boundary amount, the liquid is sent by a constant volume pump through a predetermined pipe line to flow out from a discharge port and a set amount. If the difference between the liquid flow rate and
Discharge characterized by discharging the desired liquid in a fixed amount from the discharge port so that the liquid outflow amount becomes equal to the set amount when the constant volume pump stops rotating while gradually reducing the rotation speed of the constant volume pump. Volume deceleration type liquid metering method. 2. The amount of liquid outflow is monitored at the same time when the desired liquid is outflowed, and it is known that the difference between the set amount and the liquid outflow amount has become a narrowing boundary amount by the monitoring, and the rotational speed of the constant volume pump is decelerated The discharge amount decelerating type liquid measuring method according to claim 1, which is started. 3. The discharge according to claim 1 or 2, wherein the constant volume pump stops rotating and the liquid outflow amount and the set amount become equal, and at the same time, the valve of the discharge port is closed. Volume deceleration type liquid metering method. 4. A pipeline connecting the storage means to the discharge port, a constant volume pump provided in the middle of the pipeline, a measuring means for measuring the amount of liquid flowing out from the pipeline, the constant volume pump and the metering. The control means is connected to the means for controlling, and the means and the liquid required amount are set in the control, the constant volume pump is driven to cause the desired liquid to flow out from the storage means, and the outflow amount from the signal issued by the measuring means. When the difference between this calculated value and the set amount reaches the narrowed boundary amount, the drive of the constant volume pump is started to decelerate, and when the calculated value becomes equal to the set amount, the rotation of the constant volume pump is completely A liquid measuring device characterized by being stopped. 5. The liquid measuring device according to claim 4, wherein the measuring means is a mass flow meter provided in the middle of a pipe line connecting the storage means to the discharge port.