JP2939180B2 - Liquid dispensing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention dispenses a liquid, particularly a liquid having a low specific gravity and a low specific gravity, such as an organic solvent, which is easily evaporated and has a low specific gravity, and a liquid having a high specific gravity such as hydrochloric acid. Liquid dispensing method and liquid dispensing apparatus suitable for

[0002]

2. Description of the Related Art A liquid dispensing apparatus is used which drives a syringe to draw a predetermined amount of liquid from a liquid container into a dispensing nozzle and discharges the liquid at a dispensing position from a lower end of the dispensing nozzle. When performing a dispensing operation of an organic solvent, for example, diethyl ether, diethyl ether has a high volatility, a low viscosity, a low surface tension, and a low specific gravity. During the movement, the liquid dripping easily occurs from the lower end of the dispensing nozzle. In addition, even in a dispensing operation of a liquid having a large specific gravity such as hydrochloric acid, dripping easily occurs from the lower end of the dispensing nozzle. Further, if the ambient temperature of the dispensing nozzle slightly changes, the volume of the gas portion above the liquid inside the dispensing nozzle changes, and liquid dripping easily occurs from the lower end port of the dispensing nozzle. The dripping from the dispensing nozzle causes a decrease in dispensing accuracy.

As a method for preventing liquid dripping from the lower end of the dispensing nozzle, a predetermined amount of liquid is sucked into the dispensing nozzle and the lower end of the dispensing nozzle is discharged onto the liquid surface in the liquid container. ,
Drive the syringe to slightly aspirate the inside of the dispensing nozzle,
It is conceivable to form a slight air pocket (air buffer) between the lower end of the dispensing nozzle and the lower end surface of the liquid inside the dispensing nozzle.

[0004]

However, in a method in which a predetermined amount of liquid is sucked into the dispensing nozzle and an air pocket is formed below the liquid inside the dispensing nozzle, the method of dispensing diethyl ether, hydrochloric acid, or the like, is difficult. In a few seconds, the upper end position of the air reservoir (the lower end position of the liquid inside the dispensing nozzle) drops, and the liquid drips from the lower end opening of the dispensing nozzle. It is virtually impossible to move the dispensing nozzle to the dispensing position and finish the dispensing operation within these several seconds. Even if there is an air pocket at the lower end of the dispensing nozzle that does not drip, the dispensing operation using diethyl ether or the like can easily be performed by slight vibrations such as when the dispensing nozzle moves. Cause dripping. On the other hand, when the amount of the air pocket formed at the lower end portion in the dispensing nozzle is increased, the buoyancy of the air overcomes the surface tension of the liquid in the dispensing nozzle, and the air forming the air pocket becomes bubbles. To rise inside the liquid,
By moving to the gaseous part side above the liquid, the air pool disappears and the liquid falls down from the lower end of the dispensing nozzle.

The present invention has been made in view of the above circumstances, and is easy to evaporate like an organic solvent, has low viscosity, low surface tension, and has a low specific gravity such as a liquid having a low specific gravity or hydrochloric acid. Even when dispensing large liquids,
A liquid dispensing method capable of reliably preventing liquid dripping from the lower end of the dispensing nozzle without being affected by a change in ambient temperature, thereby preventing a decrease in dispensing accuracy, and It is another object of the present invention to provide a liquid dispensing apparatus suitable for carrying out the method.

[0006]

The invention according to claim 1 is
Lowering the dispensing nozzle to immerse the lower end of the dispensing nozzle in the liquid contained in the liquid container; and driving the syringe to place the liquid in the liquid container from the lower end of the dispensing nozzle into the dispensing nozzle. A step of inhaling only a fixed amount, a step of raising the dispensing nozzle and lifting the lower end of the dispensing nozzle out of the liquid in the liquid container, a step of moving the dispensing nozzle to a dispensing position, and driving the syringe Discharging the liquid in the dispensing nozzle at the dispensing position from the lower end of the liquid dispensing nozzle, when pulling up the lower end of the dispensing nozzle from the liquid in the liquid container. When the lower end of the dispensing nozzle is above the liquid, the syringe is driven at a low speed, and a small amount of air is continuously sucked from the lower end of the dispensing nozzle into the dispensing nozzle to generate air bubbles inside the liquid in the dispensing nozzle. Occurs continuously Thereby, the state, characterized in that it continued until just before the liquid in the dispensing nozzle is ejected.

The invention according to claim 2 is a step of lowering the dispensing nozzle so that the lower end of the dispensing nozzle is immersed in the liquid contained in the liquid container, and driving the syringe to move the dispensing nozzle into the dispensing nozzle. A step of sucking a predetermined amount of the liquid in the liquid container from a lower end port, and a step of raising the dispensing nozzle to raise the lower end port of the liquid in the liquid container,
A liquid dispensing method comprising: moving the dispensing nozzle to a dispensing position; and driving the syringe to discharge the liquid in the dispensing nozzle at the dispensing position from a lower end port thereof. When pulling the lower end of the dispensing nozzle out of the liquid in the liquid container, another syringe connected to the dispensing nozzle is driven at a low speed when the lower end of the dispensing nozzle comes out of the liquid, and Continue to inhale a small amount of air into the injection nozzle from its lower end to continuously generate air bubbles inside the liquid in the dispensing nozzle, and keep this state until just before the liquid in the dispensing nozzle is discharged. It is characterized by continuing.

According to a third aspect of the present invention, there is provided a dispensing nozzle for sucking a predetermined amount of liquid contained in a liquid container from a lower end port and discharging the liquid from the lower end port, and a nozzle for holding the dispensing nozzle. Holding means, the nozzle holding means, between the lower position where the lower end of the dispensing nozzle is immersed in the liquid in the liquid container and the upper position where the lower end of the dispensing nozzle is separated upward from the liquid container A nozzle elevating means for elevating and lowering,
A nozzle moving means for moving the nozzle holding means between a position immediately above the liquid container and a dispensing position, and inhaling a predetermined amount of liquid in the liquid container from a lower end port into the dispensing nozzle; A liquid dispensing apparatus including a syringe that discharges liquid in a dispensing nozzle from a lower end port at the dispensing position, a syringe driving unit that drives the syringe, and a syringe control unit that controls the syringe driving unit. When the lower end of the dispensing nozzle is pulled out of the liquid in the liquid container, when the lower end of the dispensing nozzle comes out of the liquid, a small amount of air is sucked into the dispensing nozzle from the lower end of the dispensing nozzle. Continuously, air bubbles are continuously generated inside the liquid in the dispensing nozzle, and this state is provided with air bubble generating means for continuing this state until immediately before the liquid in the dispensing nozzle is discharged. That.

According to a fourth aspect of the present invention, in the liquid dispensing apparatus according to the third aspect, the dispensing nozzle is configured by using a disposable suction pipe.

According to a fifth aspect of the present invention, in the liquid dispensing apparatus according to the third or fourth aspect, the control circuit for controlling the syringe driving means so as to drive the syringe at a low speed is controlled by the syringe control. It is characterized in that a bubble generating means is configured by being provided in the means.

According to a sixth aspect of the present invention, in the liquid dispensing apparatus according to the third or fourth aspect, the low speed syringe, the low speed syringe driving means for driving the low speed syringe at a low speed, and the low speed syringe driving means are provided. A low-speed syringe control means for controlling, and the above-mentioned syringe for sucking a liquid into the above-mentioned dispensing nozzle and discharging the liquid from a lower end of the dispensing nozzle, and the above-mentioned low-speed syringe being selectively connected to the dispensing nozzle in a flow path. It is characterized in that a bubble generating means is constituted by the flow path switching means.

In the liquid dispensing method according to each of the first and second aspects of the present invention, a liquid dispensing operation is performed by using the liquid dispensing apparatus according to the third aspect. When a predetermined amount of liquid is injected into the dispensing nozzle and the lower end of the dispensing nozzle is pulled out of the liquid in the liquid container, the lower end of the dispensing nozzle comes out of the liquid. Until a short time before the liquid in the dispensing nozzle is discharged at the dispensing position from the lower end of the dispensing nozzle, air continues to be sucked in from the lower end of the dispensing nozzle, and air bubbles continue in the liquid in the dispensing nozzle. , The inside of the dispensing nozzle is continuously suctioned. For this reason, a slight upward suction force always acts near the lower end of the dispensing nozzle, so that even when dispensing an organic solvent such as diethyl ether or a liquid such as hydrochloric acid, the dispensing is performed. The liquid is prevented from dripping from the lower end of the injection nozzle.

[0013]

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration of a main part of a liquid dispensing apparatus used for carrying out a liquid dispensing method according to the present invention. In this dispensing device, the dispensing nozzle 10 is provided with a disposable disposable tip (hereinafter referred to as “disposable tip”).
12). The disposable chip 12 is detachably attached to the lower end of the suction pipe 14 and is immersed in a liquid, for example, diethyl ether 18 contained in the liquid container 16. The liquid 18 from the disposable chip 12
The inhaled liquid is discharged from the lower end of the disposable chip 12 at the dispensing position.

The mounting suction pipe 14 is not shown,
The nozzle holding member is held by a nozzle holding member, and the nozzle holding member is driven to move up and down by a nozzle elevating mechanism. The dispensing nozzle 10 is located at a lower position where the lower end of the disposable tip 12 attached to the lower end of the attachment suction pipe 14 is immersed in the liquid 18 in the liquid container 16 and the lower end of the disposable tip 12 is positioned in the liquid container 16. Between the camera and an upper position separated upward from the camera. Further, the dispensing nozzle 10 is moved by a nozzle moving mechanism (not shown) between a position immediately above the liquid container 16 and a position directly above the test tube 20 arranged at the dispensing position. Since each of these mechanisms is not particularly different from a conventional device, further detailed description is omitted.

The mounting suction pipe 14 of the dispensing nozzle 10 is connected to a syringe 26 by a tube 22 in a flow path.
The syringe 26 is driven by a motor 28, and is provided with a controller 30 for controlling the driving of the motor 28. Then, the controller 30 controls the motor 2
By controlling the drive of the nozzle 8, a predetermined amount of the liquid 18 is sucked from the liquid container 16 into the disposable tip 12 of the dispensing nozzle 10, and the liquid in the disposable tip 12 is dispensed into the test tube 20 from the lower end port at the dispensing position. To be discharged. Also,
In this dispensing apparatus, the controller 30 controls the motor 2
8 is controlled so that the syringe 26 can be switched at a low speed.

Next, a method for dispensing a liquid, for example, diethyl ether using the dispensing apparatus having the above-described structure will be described with reference to FIG.

The dispensing nozzle 10 is moved to a position immediately above the liquid container 16 and dispensed as shown in FIG. 2A (FIG. 2 shows only the disposable tip 12 of the dispensing nozzle 10). The nozzle 10 is lowered. Then, as shown in FIG. 2B, the lower end of the disposable chip 12 is
After being immersed in the liquid 18 contained in the liquid container 16, the syringe 26 is driven at a normal speed, and the liquid in the liquid container 16 is sucked into the disposable chip 12 from its lower end. The suction speed at this time varies depending on the diameter of the lower end of the disposable chip 12 and the viscosity of the liquid 18. For example, the lower end of the disposable chip 12 has a diameter of 1 mm, and the liquid is water, ethyl acetate, chloroform, diethyl ether or any of them. If they have similar characteristics,
0.3 cc / sec.

A predetermined amount of liquid 18 is stored in the disposable chip 12.
Is sucked, the syringe 26 is temporarily stopped, and the dispensing nozzle 10 is raised. In the process of pulling the lower end of the disposable tip 12 of the dispensing nozzle 10 out of the liquid 18 in the liquid container 16, when the lower end of the disposable tip 12 comes out above the liquid surface as shown in FIG. The syringe 26 is driven at a low speed. As a result, a small amount of air continues to be sucked into the disposable chip 12 through the lower end port, and the air becomes fine bubbles 32 as shown in FIG. The liquid floats toward the liquid surface and flows to the gas portion above the liquid 18 in the disposable chip 12. The inhalation speed at this time is
Under the same conditions as above, for example, 0.04 to 0.2
Although it is cc / sec, about 0.1 cc / sec is appropriate.

The minute flow rate is sucked into the disposable chip 12 until the dispensing nozzle 10 moves to a position above the liquid container 16 and then to a position above the test tube 20 at the dispensing position.
Alternatively, the dispensing nozzle 10 is further lowered to continue until the lower end of the disposable tip 12 is inserted into the test tube 20. During this time, an upward suction force always acts near the lower end of the disposable chip 12, so even if the liquid 18 is of a type that is liable to drool, such as diethyl ether, the disposable chip 12 may The liquid 18 does not drip from the lower end port. When the lower end of the disposable tip 12 is inserted into the test tube 20, the syringe 26 is switched to a normal speed and driven,
Dispensing nozzle 10 from syringe 26 through tube 22
The liquid 18 in the disposable chip 12 is pushed down and discharged from the lower end into the test tube 20.

Next, the liquid dispensing apparatus schematically shown in FIG. 3 is a low-speed driving device which is driven at a low speed separately from the syringe 34 driven at a normal speed and a motor and a controller (not shown) for driving the syringe 34. A syringe 36 and a motor and a controller (not shown) for driving the syringe 36 are provided, and the syringe 34 and the low-speed syringe 36 are dispensed with the dispensing nozzle 1.
A three-way switching valve 38 for connecting the flow path to 0 alternatively is provided. In this dispensing device, the three-way switching valve 38
When the liquid 18 in the liquid container 16 is sucked into the dispensing nozzle 10 and when the liquid sucked into the dispensing nozzle 10 is discharged into the test tube 20, the syringe 34 is used. And the dispensing nozzle 10 are connected in a flow path, the syringe 34 is driven, and when a predetermined amount of liquid is sucked into the dispensing nozzle 10 and the lower end port of the dispensing nozzle 10 comes out above the liquid level. Until the dispensing nozzle 10 is moved to the dispensing position and the lower end of the dispensing nozzle 10 is inserted into the test tube 20 until the low-speed syringe 36 and the dispensing nozzle 10
Is connected to the flow path, and the low-speed syringe 36 is driven. When a dispensing operation is performed using this dispensing device, the same effect as that of the dispensing device shown in FIG. 1 can be obtained. As shown in FIG. 4, a vacuum pump 42 may be used instead of the low-speed syringe 36 in the liquid dispensing apparatus shown in FIG. In FIG. 4, 4
Reference numeral 0 denotes a syringe driven at a normal speed, and reference numeral 44 denotes a three-way switching valve for selectively connecting the syringe 40 and the vacuum pump 42 to the dispensing nozzle 10 in a flow path.

[0022]

According to the liquid dispensing method of the first aspect of the present invention, it is easy to evaporate like an organic solvent, has a low viscosity, has a small surface tension, and has a large specific gravity such as a liquid having a small specific gravity or hydrochloric acid. Even when dispensing liquid, etc., dripping from the lower end of the dispensing nozzle is reliably prevented without being affected by changes in the ambient temperature, which effectively reduces dispensing accuracy. Can be prevented.

Further, by using the liquid dispensing apparatus according to the second aspect of the present invention, the liquid dispensing method according to the first aspect of the present invention can be suitably performed, and the liquid is easily dispensed. Even during the operation, the dripping from the lower end of the dispensing nozzle can be reliably prevented without being affected by the change in the ambient temperature, and the drop in dispensing accuracy can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a main part of a liquid dispensing apparatus used for carrying out a liquid dispensing method according to the present invention.

FIG. 2 is an enlarged sectional view for explaining a method of performing a liquid dispensing operation using the liquid dispensing apparatus shown in FIG.

FIG. 3 is a schematic view showing a main part of a liquid dispensing device having a configuration different from that of the liquid dispensing device shown in FIG. 1;

FIG. 4 is a schematic diagram showing a main part of a liquid dispensing device having a configuration different from that of the liquid dispensing device shown in FIG. 3;

[Explanation of symbols]

 10 Dispensing nozzle 12 Disposable tip 16 Liquid container 18 Liquid 20 Test tube 26, 34, 40 Syringe 28 Motor 30 Controller 32 Fine bubble 36 Low-speed syringe 38, 44 Three-way switching valve 42 Vacuum pump

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shintaro Nishimura 4-3-34-517, Tsuruno, Settsu-shi, Osaka (72) Inventor Masayoshi Murata 7-7-17, Higashi Tokiwadai, Toyono-cho, Toyono-gun, Osaka (56) References JP-A-2-247567 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 35/00-35/10 G01N 1/00 101 G01N 1/14

Claims (6)

(57) [Claims] 1. A dispensing nozzle is lowered and its lower end port is
A step of immersing the liquid in a liquid contained in the liquid container; a step of driving a syringe to suck a predetermined amount of the liquid in the liquid container from a lower end of the dispensing nozzle into the dispensing nozzle; Raising and lowering the lower end of the dispensing nozzle from the liquid in the liquid container; moving the dispensing nozzle to a dispensing position; and driving the syringe to move the dispensing nozzle into the dispensing nozzle at the dispensing position. Discharging the liquid from the lower end port thereof, wherein the lower end port of the dispensing nozzle comes out above the liquid when the lower end port of the dispensing nozzle is pulled up from the liquid in the liquid container. Occasionally, the syringe is driven at a low speed, a small amount of air is continuously sucked into the dispensing nozzle from the lower end thereof, and bubbles are continuously generated inside the liquid in the dispensing nozzle. In the nozzle Liquid dispensing method characterized by continued until just before the body is discharged. 2. The dispensing nozzle is lowered and its lower end is opened.
A step of immersing the liquid in a liquid contained in the liquid container; a step of driving a syringe to suck a predetermined amount of the liquid in the liquid container from a lower end of the dispensing nozzle into the dispensing nozzle; Raising and lowering the lower end of the dispensing nozzle from the liquid in the liquid container; moving the dispensing nozzle to a dispensing position; and driving the syringe to move the dispensing nozzle into the dispensing nozzle at the dispensing position. Discharging the liquid from the lower end port thereof, wherein the lower end port of the dispensing nozzle comes out above the liquid when the lower end port of the dispensing nozzle is pulled up from the liquid in the liquid container. Sometimes, another syringe connected to the dispensing nozzle is driven at a low speed, a small flow of air is continuously sucked into the dispensing nozzle from the lower end port, and bubbles are continuously generated inside the liquid in the dispensing nozzle. Raise, Liquid dispensing method, wherein a state is continued until just before the liquid in the dispensing nozzle is ejected. 3. A dispensing nozzle for sucking a predetermined amount of liquid contained in a liquid container from a lower end port and discharging the liquid from the lower end port; a nozzle holding means for holding the dispensing nozzle; Holding means, nozzle raising and lowering means for lowering the lower end of the dispensing nozzle between a lower position where the lower end of the dispensing nozzle is immersed in the liquid in the liquid container and an upper position where the lower end of the dispensing nozzle is separated upward from the liquid container; A nozzle moving means for moving the nozzle holding means between a position directly above the liquid container and a dispensing position; and inhaling a predetermined amount of liquid in the liquid container into the dispensing nozzle from a lower end port thereof. A syringe for discharging the liquid in the dispensing nozzle from the lower end port at the dispensing position, a syringe driving means for driving the syringe, and a syringe control means for controlling the syringe driving means. In the liquid dispensing apparatus provided, when the lower end of the dispensing nozzle is pulled out of the liquid in the liquid container, the lower end of the dispensing nozzle is dispensed into the dispensing nozzle when the lower end of the dispensing nozzle comes out of the liquid. It is characterized by having a bubble generating means for continuously inhaling a small amount of air to generate bubbles inside the liquid in the dispensing nozzle and continuing this state until immediately before the liquid in the dispensing nozzle is discharged. Liquid dispensing device. 4. The liquid dispensing device according to claim 3, wherein the dispensing nozzle is configured using a disposable suction pipe. 5. The liquid dispensing apparatus according to claim 3, wherein the bubble generating means is a control circuit provided in the syringe control means and controlling the syringe driving means so as to drive the syringe at a low speed. 6. A low-speed syringe, a low-speed syringe driving unit for driving the low-speed syringe at a low speed, a low-speed syringe control unit for controlling the low-speed syringe driving unit, and a liquid sucking into the dispensing nozzle. 5. The flow control device according to claim 3, further comprising a syringe for discharging the liquid from a lower end of the dispensing nozzle and a flow path switching means for selectively connecting the low-speed syringe to the dispensing nozzle. Liquid dispensing device.