JPH06160152A - Micro-volume measuring device - Google Patents

Abstract

PURPOSE:To accurately measure a micro-internal volume of a capillary or the like. CONSTITUTION:A micro-volume measuring device is provided with a pipe C having a known internal volume, a pressure control device 2 feeding the preset pressure to the pipe C, a pressure sensor 6 detecting the pressure of the pipe C, the first valve 3 applying the preset pressure fed from the pressure control device 2 to the pipe C, the second valve 4 releasing the preset pressure of the pipe C to a measured object at the preset time after the first valve 3 is closed, and a controller 8 calculating the internal volume of the measured object based on the preset pressure of the pipe C detected when the first valve 3 is opened and the second valve 4 is closed, the pressure detected when the first valve 3 is closed and the second valve 4 is opened, and the known internal volume of the pipe C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microvolume measuring device for measuring the volume inside a device composed of pipes and valves, especially the microvolume of a device using a capillary.

[0002]

2. Description of the Related Art Conventionally, as a method for determining the volume of an object to be measured, a liquid whose specific gravity is known has been injected into the object to be measured, and its internal volume is determined by the change in its weight.

[0003]

However, in the above-mentioned conventional measuring method, since the liquid is injected, in a device using a capillary (capillary) or the like, the liquid may not completely reach the details or the surface tension may cause a problem. Since it was difficult to completely fill the opening of the capillary, an error occurred in the measured value, and there was the inconvenience that a precise minute volume could not be measured.

Also, some devices cannot inject a liquid, and in such a case, there is an inconvenience that the volume cannot be measured.

In view of such inconveniences, an object of the present invention is to provide a minute volume measuring device capable of accurately measuring the volume of a minute object to be measured.

[0006]

The microvolume measuring device of the present invention is, for example, as shown in FIG. 1, a pipe means c having a known internal volume and a pressure control for supplying a predetermined pressure to the pipe means c. Means 2, pressure detecting means 6 for detecting the pressure of the piping means c, first valve 3 for applying a predetermined pressure supplied from the pressure control means 2 to the piping means c, and closure of the first valve 3. After that, after a predetermined time, the second valve 4 for releasing the predetermined pressure of the piping means c to the DUT 10, and the first valve
The predetermined pressure of the piping means c detected when the valve 3 is opened and the second valve closed, and the pressure and the piping means detected when the first valve 3 is closed and the second valve 4 is opened. The control means 8 calculates the internal volume of the DUT 10 based on the known internal volume of c.

[0007]

The first valve is opened, and when the second valve is closed, a constant pressure is supplied to the pipe having a known internal volume.
The pressure at this time is detected. After the detection, the first valve is closed, the second valve is opened, the pressure of the pipe is supplied to the object to be measured, and the pressure at this time is detected. This pressure value and the known internal volume of the pipe and The internal volume of the object to be measured can be calculated based on the pressure detected when the first valve is opened and the second valve is closed. Therefore, as compared with the measurement method using a liquid or the like, the measurement error due to the surface tension or the like is eliminated, and thus the accurate measurement of a minute volume becomes possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the microvolume measuring device of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 denotes a pump which supplies, for example, air pressure to the pressure control device 2 through a pipe a, and the pressure control device 2 controls the pressure to a predetermined constant pressure.

Reference numeral 3 is a first valve for opening and closing the pressure applied by the pressure control device 2 through the pipe b, and is connected to one end of the pipe c. This pipe c
Has a known internal volume V ₁ measured in advance. The second valve 4 is provided at the other end of the pipe c.
Are connected. An object to be measured 10 whose internal volume is measured is connected to the second valve 4 via a pipe d.

Reference numeral 5 denotes a valve control unit, which controls the drive motors M ₁ of the valves 3 and 4 in response to a control signal from a control unit 8 described later.
And M ₂ are supplied to supply and release the pressure in the pipe c.

Reference numeral 6 denotes a pressure sensor, which detects the pressure in the pipe c which changes depending on the opening and closing of the valves 3 and 4, and outputs it to the A / D converter 7. This A / D converter 7 includes a pressure control device 2
Is also input, converted into a digital signal together with the pressure signal of the pipe c, and output to the control unit 8 described below.

Reference numeral 8 denotes a control unit composed of a CPU, a RAM, a ROM and the like. The ROM has data of the known internal volume V ₁ of the pipe c together with the opening time of the valve 3 and the closing time of the valve 4.
In addition, the closing time of the valve 3 and the closing time of the valve 4 are stored and held in advance. Further, the control unit 6 controls the known internal volume V _{1 of} the pipe c, the pressure P _{1 of the} pipe c detected when the valve 3 stored in the RAM is opened and when the valve 4 is closed, and when the valve 3 is closed and when the valve 3 is closed. The internal volume Vx of the object to be measured 10 is calculated based on the pressure P ₂ of the object to be measured 10 (described later) detected when the valve 4 is opened.

A D / A converter 9 converts a control signal for controlling opening and closing of the valves 3 and 4 from the control unit 8 into an analog signal and outputs the analog signal to the valve control unit 5.

In the above structure, the power is turned on to drive the pump 1 to apply, for example, air pressure to the pressure control device 2,
The pressure control device 2 maintains the predetermined pressure. A signal corresponding to this predetermined pressure is output to the control unit 8 via the A / D converter 7 and the pressure is monitored.

The control unit 8 outputs a control signal for opening the valve 3 to the valve control unit 5 via the D / A converter 9 and a control signal for maintaining the valve 4 closed, and the valve control unit 5 Outputs a drive signal corresponding to the control signal to the motor M ₁ and the motor M ₂ . Therefore, the valve 3 is opened and the valve 4 remains closed.

By opening the valve 3, air of a predetermined pressure is added from the pressure control device 2 to the pipe c through the pipe b,
After a predetermined time, the valve 3 is closed. The pressure P ₁ at this time is detected by the pressure sensor 6 and is stored in the RAM of the control unit 8 via the A / D converter 7.

Then, a predetermined time after the valve 3 is closed, a control signal for opening the valve 4 is output from the control unit 8 to drive the valve 4 via the D / A converter 9 and the valve control unit 5. The motor M ₂ is driven and the valve 4 is opened. When the valve 4 is opened, air of a predetermined pressure in the pipe c flows into the DUT 10, and at that time, the pressure P ₁ in the pipe c and the DUT 10 drops to P _{2 and the} pressure sensor 6 is used. It is detected and taken into the RAM of the control unit 8 via the A / D converter 7.

Where P ₁ : valve 3 open and valve 4
Pressure of pipe c when closed, P ₂ : pressure of pipe c and DUT 10 when valve 3 is closed and valve 4 is opened, V ₁ : known internal volume of pipe c, V ₂ : known contents of pipe c Product V ₁ +
Unknown internal volume Vx of the object to be measured 10, T ₁ : ambient temperature of the pipe c (when the valve 3 is open and valve 4 is closed), T ₂ : ambient temperature of the pipe c and the object to be measured (valve 3 is closed and the valve 4 is closed).
(At the time of opening), the following formula is established according to Boyle-Charles' law.

[0019]

[Formula 1] P ₁ · V ₁ / T ₁ = P ₂ · V ₂ / T ₂

At this time, within a minute time, for example, 100 ms (Mi
Ambient temperature T ₁= T₂Are almost equal
Can be regarded as

[0021]

[Equation 2] P ₁ · V ₁ = P ₂ · V ₂

Since P ₁ and P ₂ are detected by the pressure sensor 6, and the internal volume V ₁ of the pipe c is known, V _1
2 can be calculated. Since V ₂ is the sum of the known internal volume V ₁ of the pipe c and the unknown internal volume Vx of the DUT 10 as described above, the internal volume Vx of the DUT 10 is

[0023]

[Number 3] can be obtained from the Vx = V ₂ -V _1.

In this way, the unknown internal volume Vx of the object to be measured 10 is detected by the control unit 8 at the pressure P ₁ detected when the valve 3 is opened and the valve 4 is closed, and the valve 3 is closed and the valve 4 is opened. The pressure P ₂ and the known internal volume V ₁ of the pipe c, which are sometimes detected, are input and calculated.

FIG. 2 shows another embodiment of the present invention. The parts corresponding to those in the embodiment of FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

In the above-mentioned structure, the pressure is switched by using two valves, but in this example, the pressure is switched by using the three-way switching valve and the constant pressure is obtained by adjusting the manual valve. I chose

In FIG. 2, for example, air pressure is applied to the buffer tank 11 from the pump 1 through the pipe e. The buffer tank 11 is for stabilizing the pressure supplied from the pump 1. From the pipe e, a pipe e ₁ is branched from the middle, and a manual valve 12 is attached to the tip. The manual valve 12 releases or stops the pressure supplied from the pump 1 to the outside, and the buffer tank 11
The pressure within is adjusted to maintain a predetermined constant pressure value.

As the three-way switching valve 13, a valve whose internal volume V ₁ a in its two openings is known in advance is used. This internal volume V ₁ a
Are stored in, for example, a ROM in the control unit 8. In addition, the three-way switching valve 13 drives the motor under the control of the valve control unit 5 to rotate the motor by 90 degrees, so that the pressure sensor 6 is moved from the buffer tank 11 and the pressure sensor 6 side.
And switch to the DUT 10 side. Buffer tank 1
1, the pressure sensor 6 and the DUT 10 are connected to the three-way switching valve by the pipes f, g and h.

The output of the pressure sensor 6 is converted into a digital signal by the A / D converter 7 and output to the control unit 8, and the display unit 14 displays and monitors the pressure value.

In such a configuration, when the internal volume Vxa of the object to be measured 10 is obtained, the control unit 8 drives the motor through the D / A converter 9 and the valve control unit 5 so that the 3
The one-way switching valve 13 is switched to the buffer tank 11 and the pressure sensor 6 side. The pressure supplied from the pump 1 to the buffer tank 11 is detected by the pressure sensor 6, and the pressure value is displayed on the display unit 14 via the A / D converter 7 and the control unit 8. Check this pressure value. Meanwhile, the manual valve 12 is used to adjust to a constant pressure value P ₁ a.

When a constant pressure value P ₁ a is obtained, the three-way switching valve 13 is switched to the side of the object to be measured 10 and the pressure sensor 6, and the pressure value P ₂ a in the object to be measured 10 is detected by the pressure sensor 6. It is detected and output to the control unit 8 via the A / D converter 7.

[0032] In this way, the pressure P ₁ a of the buffer tank 11 detected from the known internal volume V ₁ a of the pressure P ₂ a and 3-way switching valve 13 of the object 10, and the above-described embodiment Similarly, the internal volume Vxa of the DUT 10 can be obtained by the calculation of the control unit 8.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0034]

As described above, according to the present invention, a constant pressure is supplied to a pipe having a known internal volume, and the pressure detected at this time and the pressure of the pipe are supplied to the object to be measured. Since the internal volume of the object to be measured can be detected based on the pressure detected at this time and the known internal volume of the pipe, it is possible to measure by surface tension, etc., as compared to the measurement method using liquid etc. Since there is no error, it is possible to accurately measure a minute volume. Further, unlike the conventional case, since liquid or the like is not used, the flow path of the object to be measured is not contaminated. Furthermore, since it is only necessary to connect a pipe to the object to be measured at the time of measurement, there is an advantage that the measurement can be easily performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a microvolume measuring device of the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 2 Pressure control device 3 First valve 4 Second valve 6 Pressure sensor 8 Control unit 10 Object to be measured c Piping

Claims (1)

[Claims] 1. A piping means having a known internal volume in advance, a pressure control means for supplying a predetermined pressure to the piping means, a pressure detection means for detecting the pressure of the piping means, and a supply by the pressure control means. A first valve for applying the predetermined pressure to the piping means, and a second valve for releasing the predetermined pressure of the piping means to an object to be measured at a predetermined time after closing the first valve. And the predetermined pressure of the piping means detected when the first valve is opened and when the second valve is closed, and when the first valve is closed and the second valve is opened. And a control means for calculating the inner volume of the object to be measured based on the determined pressure and the known inner volume of the piping means.