JPH026568B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides an ultrafiltration method for separating a protein solution (hereinafter referred to as a liquid to be concentrated) into a low molecular weight substance and a high molecular weight substance using a concentrator equipped with an ultrafiltration membrane. A drive control device for a protein solution concentrator according to the present invention has a simple configuration and is capable of automatically concentrating a concentrated liquid to a desired concentration using a detection signal of the concentration of the concentrated liquid.

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 is a block diagram showing an example of a drive control device for a negative pressure concentrator. In the figure, 1 is a concentrator with a built-in ultrafiltration membrane that separates low-molecular weight substances and high-molecular weight substances, and 2 is a concentrator. 1. For example, ascites,
A feeding pump 3 is a concentrating pump connected to the concentrator 1, which feeds a liquid to be concentrated such as pleural effusion, blood, starch liquid, whey, etc. at a constant flow rate.

Reference numeral 4 denotes a concentration sensor provided on the output side of the concentrator 1, which can be a known concentration meter or ultrasonic density meter that utilizes changes in the refractive index of light. 5 is a sampling circuit that is connected to the concentration sensor 4 and measures the concentration value in short cycles; 6 is a D/A converter that converts the digital signal output from the sampling circuit 5 into an analog signal; 7 is a D/A converter;
The D/A converter 6 is connected to the output end of the A converter 6.
This is a smoothing circuit that smoothes the output signal from the concentration sensor 4, sampling circuit 5, D/A
The converter 6 and the smoothing circuit 7 constitute a concentration detection circuit 8.

9 is a density setting circuit, and 10 is an arithmetic circuit. The arithmetic circuit 10 compares the concentration setting voltage signal from the concentration setting circuit 9 with the concentration analog voltage signal from the concentration detection circuit 8, and performs proportional-integral-differential calculations so that the deviation value becomes zero. Reference numeral 11 denotes a limit circuit, which accepts the calculation output from the calculation circuit 10 within a voltage corresponding to the upper and lower limit rotation speeds of the concentration pump 3 and sends a rotation speed command signal to the concentration pump speed control circuit 12. is set to send out. 13 is a speed setting circuit for the concentration pump 3, and the concentration pump 3 is activated at any time.
It is connected to the speed control circuit 12 via a signal selection changeover switch 14. 15 is a first rotation speed detector that detects the rotation speed of the concentration pump 3; 16 is a second rotation speed detector that detects the rotation speed of the liquid feeding pump 2; and 17 is the first and second rotation speed. Detector 1
5, 16 and the limiter circuit 11, and is a comparison circuit inserted and connected between the limiter circuit 11 and the rotation detector 1.
It is configured to receive the output signals from the limiter circuits 5 and 16 and send out a control signal for the limit value of the limiter circuit 11. 18 is a drive motor for the concentration pump 3.

Next, the operation of the above configuration will be explained.

The liquid to be concentrated is sent to the concentrator 1 at a constant flow rate by a liquid sending pump 2. In the concentrator 1, high molecular weight substances and low molecular weight substances are separated, and the low molecular weight substances are drawn out and discharged by a concentrating pump 3. The faster the rotation speed of the concentration pump 3 is, the more low-molecular weight substances are discharged and the concentration of high-molecular weight substances in the liquid that exits the concentrator 1 increases; A small amount of material is discharged and the high molecular weight material concentration of the liquid leaving the outlet of the concentrator 1 is reduced.

Assuming that the concentration of the concentrated liquid exiting the concentrator 1 is depicted as a waveform as shown in FIG. 2A over time, this concentration is detected by the concentration sensor 4. The electrical signal corresponding to the concentration from the concentration sensor 4 is sent to a second sampling circuit 5.
As shown in Figure B, the digital signal is converted into a digital signal, and each time this digital signal is measured, the D/A
After being D/A converted by the converter 6 as shown in FIG. 2C, it passes through the smoothing circuit 7 and is applied to the arithmetic circuit 10 as a smoothed concentration detection signal as shown in FIG. 2D. Ru.

The arithmetic circuit 10 compares the concentration detection signal with the concentration detection signal from the concentration setting circuit 9, and performs proportional-integral-differential calculation so that the deviation value between the two becomes zero. When the calculation output from the calculation circuit 10 is sent to the limiter circuit 11, the limiter circuit 11 regulates the calculation output to within each voltage corresponding to the minimum and maximum rotational speed of the concentration pump 3, and then controls the calculation output to the concentration pump 3. 3 rotation speed command signal is output.

At this time, if the signal selection switch 14 is turned to the A side, the rotation speed command signal is selected and applied to the concentration pump speed control circuit 12.

The concentration pump speed control circuit 12 is connected to the drive motor 1
The motor 18 has a function of adjusting the rotation speed of the motor 18 by phase control, for example, and has a speed signal feed-packed from the first rotation detector 15, and when the rotation speed command signal is received, the motor 18 is adjusted according to the voltage. , that is, change the rotation speed of the concentration pump 3,
This causes the concentration of the concentrated liquid to follow the concentration setting value. In addition, signal selection switch 1
4 to the M side, the speed setting circuit 13
The rotation speed command voltage by the potentiometer is selected, and thereby the rotation speed of the concentration pump 3 can be changed independently by manual operation.

Here, in the negative pressure type concentrator, unless the relationship is satisfied in which the amount of the liquid to be concentrated is larger than the amount of the concentrated liquid, there is a risk that the liquid will not be passed through the concentration sensor 4 or that it will flow backwards. This possibility is particularly high when the signal selection changeover switch 14 described above is turned to the A side.

However, in the above configuration, the rotation speed of the concentration pump 3 and the rotation speed of the liquid feeding pump 2 are detected by the first and second rotation speed detectors 15 and 16, and the comparison circuit 17 determines the state of liquid feeding amount>concentrated liquid amount. If a situation where the amount of liquid sent < amount of concentrated liquid occurs,
A control signal is sent to lower the high limit value of the limiter circuit 11 to lower the rotational speed of the concentration pump 3. Therefore, the state of liquid feeding amount>concentrated liquid amount can always be maintained reliably.

FIG. 3 is a block diagram showing an example of a drive control device for a positive pressure concentrator, and the same parts as in FIG. 1 are given the same numbers and detailed explanations will be omitted.

In this positive pressure type, it is necessary to prevent the rotation speed of the concentration pump 3 from reaching zero.

In other words, when the number of revolutions is zero, the concentrated liquid does not flow to the concentration sensor, and the concentration of the concentrated liquid is not measured. Therefore, if the minimum rotational speed of the concentration pump 3 is regulated by the low limit value of the limiter circuit 11, the minimum flow rate of the concentrated liquid can be guaranteed and the above problem can be solved.

In addition, in each embodiment, pressure detectors, pressure alarms, etc. are installed at necessary locations in case an abnormal withstand pressure occurs in the concentrator 1, and in the event of an abnormality, the concentration pump 3 and the liquid transfer pump 2 are It is natural to introduce a means to immediately stop the drive.

As described above, the present invention allows the concentrated liquid to automatically follow the desired concentration using a simple circuit configuration that controls the driving of the concentration pump using the detection signal of the concentrated liquid concentration from the concentrator. It is possible to provide a drive control device for a concentrator that can be easily connected to other control systems.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a drive control device for a concentrator according to the present invention, FIGS. 2A to 2D are signal waveform diagrams of various parts of the concentration detection circuit in the same device, and FIG. 3 is a diagram showing another embodiment. FIG. DESCRIPTION OF SYMBOLS 1...Concentrator, 2...Liquid sending pump, 3...Concentration pump, 8...Concentration detection circuit, 9...Concentration setting circuit, 10...Arithmetic circuit, 11...Limiter circuit,
12...Concentration pump speed control circuit, 15...First
rotation speed detector, 16... second rotation speed detector,
17... Comparison circuit.

Claims (1)

[Claims] 1 A concentrator that is connected to a concentrator pump and concentrates and drains the liquid to be concentrated, which is fed at a constant flow rate by a liquid pump, and a concentrator that detects the concentration of the concentrated liquid from this concentrator and responds to the concentration value. A concentration detection circuit that outputs a concentration detection signal, an arithmetic circuit that compares the concentration setting signal from the concentration setting circuit with the concentration detection signal and calculates the deviation value to zero, and an output from the arithmetic circuit. A limit circuit accepts the signal within a voltage corresponding to the upper and lower limit rotation speeds of the concentration pump and sends a rotation speed command signal to the concentration pump speed control circuit, and a limit circuit that controls the rotation speeds of the concentration pump and the liquid delivery pump. 1st and 2nd to detect respectively
A drive control device for a concentrator, comprising: a rotation speed detector; and a comparison circuit that receives output signals from these detectors and sends a limit value control signal to the limiter circuit.