JPH0743288A - Osmotic pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To reduce the size of sample container while enhancing the stirring efficiency by setting a frequency for generating a node on the shaking rod of a stirrer thereby shaking the stirrer with small amplitude and multiple frequencies. CONSTITUTION:When a pulse generator in an electric circuit 68 regulates the pulse frequency thus regulating the exciting frequency of an electromagnetic coil 66 appropriately, the shaking rod 42 of a stirrer for shaking a metal plate 64 through the coil 66 can be set with a frequency generated at a node 42a. Consequently, the shaking rod 42 shakes the stirrer with relatively large number of frequencies at the time of cooling but the amplitude of oscillation is restricted at the free end part 42b for stirring the sample liquid 54 in the container 52. This constitution allows the downsizing of the container 52 and the entire apparatus while enhancing the stirring efficiency of the sample liquid 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an osmotic pressure measuring device, and more particularly to an osmotic pressure measuring device by a so-called freezing point depression method for obtaining an osmotic pressure by measuring a freezing point temperature of a sample solution.

[0002]

2. Description of the Related Art Generally, in clinical tests, the osmotic pressure of body fluids such as plasma and urine or dialysate is measured. In this measurement, an osmotic pressure measuring device by a so-called freezing point depression method (hereinafter sometimes simply referred to as an osmotic pressure measuring device) is widely used.

Here, the osmotic pressure measuring device by the freezing point depression method will be briefly described. Generally, the freezing point of a solution is lower than the freezing point of a pure solvent in proportion to the molar concentration of the solute contained in the solution (this is called freezing point depression phenomenon). On the other hand, the osmotic pressure also decreases in proportion to the number of molecules (atoms) contained in the solution. Therefore, from this fact, the osmotic pressure can be obtained by measuring the decrease in the freezing point, that is, the freezing point depression degree. The osmotic pressure measuring device by the freezing point depression method is constructed based on such a principle.

That is, in FIG. 4, the osmotic pressure measuring apparatus generally includes a cooling system 10 including a power source 12, a cooling unit 14, a cooling tank 16 and the like, a thermistor 22, an amplifier 24, an A / D converter 26 and a thermistor 28 and the like. And a control system 30 including a touch key 32, a display unit 34, a printer 36, an external output device 37, a microcomputer 38, and the like, and further supports a stirrer 44 of a stirrer vibrating rod 42 and a gripping arm 46. The drive system 40 is composed of an elevating head 48.

In such a structure, one of the containers 52 on the turntable 50 has the thermistor 22 and the agitator vibrating rod 42 inserted into the sample solution (the plasma or the like) 54 via the gripping arm 46. When the sample solution 54 in the container 52 is lowered into the cooling tank 16 by vibrating the vibrating rod 42 of the stirrer narrowly, the sample solution 54 is stirred so that the temperature of the sample solution becomes uniform. As shown, the freezing point temperature of −t ₁ ° C. is passed and supercooling is performed to a predetermined supercooling temperature of −t ₂ ° C. This supercooling temperature is detected by the thermistor 22, and the agitator vibrating rod 42 is connected to the control system 30 and the agitator 4.
Vibration is rapidly widened through 4. That is, the agitator vibration rod 42 is strongly brought into contact with the container 52 by the wide vibration, and the ice stimulus is applied.

When ice crystal nuclei are generated by the freezing stimulus due to this vibration, the sample liquid 54 is in the equilibrium of ice / water coexistence / flat freezing point during the time T ₁ -T ₂ despite the progress of cooling. The temperature is maintained. This freezing point temperature is detected by the thermistor 22, and the control system 30 is detected from this detected temperature.
The osmotic pressure converted via is displayed on the display unit 34 and, at the same time, is output from the printer 36 and the external output device 37. The thermistor 28
Is for measuring the temperature in the cooling tank 16 and includes an amplifier 24, A
This measured temperature is input to the control system 30 via the / D converter 26, and the cooling system 10 is controlled to a required temperature based on the measured temperature value.

Therefore, according to such an osmotic pressure measuring device by the freezing point lowering method, the freezing point temperature is measured from the stable temperature range in the coexisting state of ice and water, so that an accurate osmotic pressure is required. Moreover, its configuration and measurement operation also have the advantage that they are achieved relatively easily.

[0008]

However, the above-described osmotic pressure measuring device has the following drawbacks with respect to the stirring of the sample liquid due to vibration.

That is, the sample liquid is stirred by stirring the stirrer vibrating rod 42 as described above (usually an electromagnetic vibrator).
This is achieved by vibrating narrowly by 44. However, in the conventional osmotic pressure measuring device, the stirrer vibrating rod 42 was vibrated like a pendulum as shown in FIG. 6 for explaining the vibrating state.

Therefore, in the conventional osmotic pressure measuring device, if the vibration is strongly set during supercooling, the agitator vibrating rod 4
Since the amplitude w'of 2 becomes wide and there is a fear of being in strong contact with the container 52 and freezing, the vibration must be set weakly. As a result, the stirring efficiency of the sample liquid 54 was poor. Strongly vibrating the stirrer vibrating rod 42 in order to increase the stirring efficiency leads to an increase in the size of the container 52, and further the container 52.
There is a problem that the increase in the size of the device increases the required amount of the sample solution 54 and increases the size of the entire apparatus. On the other hand, it is obvious that stirring with weakened vibration of the stirrer vibrating rod 42 lowers the stirring efficiency, causes a temperature distribution in the sample liquid 54, and causes a drawback that the temperature of the sample liquid 54 cannot be accurately measured.

Therefore, an object of the present invention is to improve the stirring efficiency of the sample liquid and at the same time reduce the size of the sample liquid container by vibrating the vibrating rod of the stirrer, which applies the ice stimulus to the sample liquid, with a small amplitude and multiple frequencies. An object of the present invention is to provide an osmotic pressure measuring device that can be realized.

[0012]

In order to achieve the above object, an osmotic pressure measuring device according to the present invention uses a supercooled sample liquid in a container via ice stimulus by vibration of a stirrer vibrating rod. In the osmotic pressure measuring device for measuring the freezing point temperature of this sample liquid to determine the osmotic pressure by converting into an ice / water coexisting state, the stirrer vibrating the stirrer vibrating rod is It is characterized in that it is set to the frequency at which the vibration node is generated in the vibrating rod of the stirrer.

In this case, the agitator includes a leaf spring and a metal plate for supporting the agitator vibrating rod on the base, an electromagnetic coil for vibrating the metal plate to vibrate the agitator vibrating rod, and the electromagnetic coil. And an electric circuit for driving the motor and defining the excitation frequency thereof.

Further, the electric circuit comprises a power supply for driving the electromagnetic coil, a pulse generator for generating a pulse, and a transistor for switching a current flowing from the power supply to the electromagnetic coil in accordance with the pulse from the pulse generator. can do.

[0015]

According to the osmotic pressure measuring device of the present invention, the vibrating rod of the stirrer is vibrated at the frequency forming the vibrating node in order to regulate the amplitude. Therefore, the free end portion of the agitator vibrating rod that agitates the sample liquid in the container is set to have a small amplitude even at multiple frequencies. That is, the stirring efficiency of the sample liquid can be improved, and at the same time, the sample liquid container can be downsized.

[0016]

EXAMPLES Examples of the osmotic pressure measuring device according to the present invention will be described in detail below with reference to the accompanying drawings.
For convenience of explanation, the same components as those of the conventional structure shown in FIGS. 4 to 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, as is clear from the above, the osmotic pressure measuring device according to the present invention applies the vibration icing stimulus to the sample liquid by vibrating the agitator vibrating rod 42 and the agitator 44 in FIG. Other than that, the other structure is the same as that of the conventional one. Therefore, the following description is limited to the agitator vibrating rod and agitator.

Therefore, the osmotic pressure measuring device according to the present invention will be described. In the stirrer 44, the frequency of the stirrer vibrating rod 42 is set to the frequency generated by the vibrating node 42a (see FIG. 3 described later). To be set. That is, the stirrer 44 is
1, a leaf spring 62 and a metal plate 64 for supporting the agitator vibrating rod 42 on the base 60, and the agitator vibrating rod 42
An electromagnetic coil 66 that vibrates the metal plate 64 to vibrate the
And an electric circuit 68 for driving the electromagnetic coil 66 and defining the excitation frequency thereof. Then, the electric circuit 68, as shown in FIG. 2, generates a pulse of a power source 70 for driving the electromagnetic coil 66, a pulse generator 74 for generating a pulse 72, and a current flowing from the power source 70 to the electromagnetic coil 66. And a transistor 76 that switches according to the pulse 72 from the device 74.

Therefore, in such a structure, when the frequency of the pulse 72 is adjusted by the pulse generator 74 to appropriately adjust the exciting frequency of the electromagnetic coil 66, the electromagnetic coil 66 vibrates and agitates through the metal plate 64. As shown in FIG. 3, the vibration frequency of the vessel vibration rod 42 can be set to a frequency at which the agitator vibration rod 42 resonates in the state where the node portion 42a is present. Therefore, according to the present invention, the stirrer vibrating rod 42 vibrates at a relatively high frequency during cooling,
The amplitude w of the free end portion 42b of the stirrer vibrating rod 42 that stirs the sample liquid 54 in the container 52 is suppressed to be narrow.

As described above, according to the present invention, although the vibrating rod of the stirrer is vibrated at a relatively high frequency, its amplitude is suppressed narrowly, so that the container (and the entire apparatus) is downsized. At the same time, the efficiency of stirring the sample liquid in the container can be improved.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various design changes can be made without departing from the spirit thereof. Further, it is obvious that the present invention is not limited to the above-described osmotic pressure measurement for a body fluid or the like in a clinical test and can be similarly applied to other general solutions.

[0022]

As described above, in the osmotic pressure measuring device according to the present invention, the supercooled sample liquid in the container is brought into the ice / water coexisting state through the icing stimulation by the vibration of the agitator vibrating rod. In the osmotic pressure measuring device for determining the osmotic pressure by measuring the freezing point temperature of this sample liquid by converting, the frequency of the agitator vibrating rod is set to the frequency at which the vibrating nodes are generated in the agitator vibrating rod. By virtue of such a constitution, the agitator vibrating rod can suppress the amplitude thereof narrowly even though the sample liquid is strongly agitated at a relatively high frequency.

Therefore, according to the present invention, the container (and the entire apparatus) for containing the sample liquid can be constructed in a small size, and at the same time, the stirring efficiency of the sample liquid in the container can be improved.

[Brief description of drawings]

FIG. 1 is an overall plan view showing an embodiment of a stirrer vibrating rod in an osmotic pressure measuring device according to the present invention.

FIG. 2 is a circuit diagram showing an electric circuit of the stirrer shown in FIG.

FIG. 3 is a side view showing a resonance state with a node portion of the agitator vibrating rod shown in FIG.

FIG. 4 is an overall configuration diagram illustrating a general osmotic pressure measurement device.

5 is a characteristic diagram for explaining a temperature change of a sample liquid in the osmotic pressure measurement device shown in FIG.

6 is a diagram showing a vibrating state of the agitator vibrating rod shown in FIG. 4;
It is a side view corresponding to.

[Explanation of symbols]

 42 Stirrer Vibrating Rod 42a Node 42b Free End 44 Stirrer 52 Container 54 Sample Liquid 60 Base 62 Leaf Spring 64 Metal Plate 66 Electromagnetic Coil 68 Electric Circuit 70 Power Supply 72 Pulse 74 Pulse Generator 76 Transistor

Claims (3)

[Claims] 1. A freezing state sample solution in a container is converted into an ice / water coexisting state through freezing stimulation by vibration of a stirrer vibrating rod to measure the freezing point temperature of this sample solution and permeate. In an osmotic pressure measuring device for obtaining pressure, the agitator vibrating the agitator vibrating rod is characterized in that the driving frequency thereof is set to a frequency at which vibrating nodes are generated in the agitator vibrating rod. measuring device. 2. The stirrer comprises a leaf spring and a metal plate for supporting the stirrer vibrating rod on a base, an electromagnetic coil for vibrating the metal plate to vibrate the stirrer vibrating rod, and a drive for this electromagnetic coil. The osmotic pressure measuring device according to claim 1, further comprising an electric circuit that regulates the excitation frequency. 3. The electric circuit comprises a power supply for driving an electromagnetic coil, a pulse generator for generating a pulse, and a transistor for switching a current flowing from the power supply to the electromagnetic coil according to a pulse from the pulse generator. The osmotic pressure measuring device according to claim 2.