JP3312087B2 - Liquid level detecting method and automatic dispensing device in automatic dispensing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic dispensing apparatus and a liquid level detecting method, and more particularly, to a method for detecting a liquid level in a pipe system after lowering a nozzle while discharging air from a nozzle tip opening. about the came air disconnect.

[0002]

2. Description of the Related Art An automatic dispensing apparatus is an apparatus used for distributing various liquid samples (for example, blood samples) to a plurality of containers. In the automatic dispensing device, a sample is sucked by a nozzle which is movable three-dimensionally,
Thereafter, the nozzle is moved to discharge a predetermined amount of the sample into a desired container. Note that a disposable type nozzle is often used.

[0003] The nozzle is connected via an air hose to a pump composed of a syringe and a piston, and the pump is operated to suck and discharge a sample by the nozzle. A pressure sensor for detecting the internal pressure of the piping system is arranged at any part of the piping system, and various controls are executed by a control unit built in the apparatus main body based on a detection signal of the pressure sensor. . One of the controls is detection of the liquid level of the sample.

In the case of sucking a sample, if the nozzle is made to enter the sample too deeply, the sample adheres to the outer surface of the nozzle more than necessary, and the attached sample is ejected and dispensed at the time of ejection. There is a problem that the accuracy is reduced or the sample attached to the outer surface of the nozzle becomes a droplet and drops during the movement of the nozzle. Therefore, the amount of entry of the nozzle tip into the sample needs to be constant and set to a minimum, but for that purpose, it is necessary to know the height of the liquid level of the sample.

Therefore, conventionally, the nozzle is lowered while discharging a small amount of air from the opening at the tip of the nozzle by operating the pump, and the tip of the nozzle comes in contact with the liquid surface of the sample to close the opening at the tip of the nozzle. The rise in the internal pressure of the piping system due to this is detected, and the liquid level is determined based on the rise in the internal pressure.

After the liquid level is detected, the internal pressure of the piping system is higher than the atmospheric pressure, and it is necessary to return the internal pressure of the piping system to the atmospheric pressure in order to suck the sample. That is, in the related art, assuming that the sample is sucked, the internal pressure of the nozzle is set to the atmospheric pressure, and the pump is operated to suction based on the internal pressure to suction a desired amount of the sample. There are two conventional methods for returning the internal pressure of the piping system to atmospheric pressure after detecting the liquid level.

One is a method disclosed in Japanese Patent Application Laid-Open No. 2-196964. In this method, after the liquid level is detected, the nozzle is once pulled up about 1 cm, the tip of the nozzle is detached from the liquid level, and in that state, the piston is pushed in, the air in the piping system is discharged, and the internal pressure of the piping system is returned to the atmospheric pressure. ,
Thereafter, the nozzle is lowered by about 1 cm, and the tip of the nozzle is again moved into the sample to a certain depth to perform suction.

The other is disclosed in the above publication and Japanese Patent Application No. 5-247.
No. 719. In this method, the lowering of the nozzle is stopped after the liquid level is detected, and the atmospheric pressure release valve provided in the piping system is operated, so that the internal pressure of the piping system becomes atmospheric pressure. Until it is left naturally.

[0009]

However, in the first conventional method, in order to return the internal pressure of the piping system to the atmospheric pressure, the operation of raising and lowering the nozzle after detecting the liquid level must be added separately. However, there is a problem that the dispensing processing speed is reduced. Also in the second conventional method, it is necessary to wait until the internal pressure of the piping system naturally returns to the atmospheric pressure, and the dispensing processing speed decreases.

In the first conventional method, air is continuously discharged even when the nozzle is pulled up after the liquid level is detected, and air discharged from the tip of the nozzle may generate bubbles on the liquid surface of the sample. Was. If the generated bubbles are sucked when the sample is sucked, the suction amount becomes insufficient, and the dispensing accuracy is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to generate air bubbles after discharging air from a nozzle tip and detecting a liquid level in an automatic dispensing apparatus. the rather rapid internal pressure of the pipeline is to make it back to atmospheric pressure.

[0012]

To achieve the above object, the present invention provides a nozzle for sucking and discharging a sample, a pump connected to the nozzle, and a piping system from the nozzle to the pump. A pressure sensor for detecting the internal pressure of the liquid, and a moving means for moving the nozzle , in a liquid level detection method of an automatic dispensing device, the discharge operation of the pump to discharge air from the nozzle tip, the nozzle An air discharge lowering step of lowering from above the sample container, and during the lowering of the nozzle, the internal pressure of the piping system is monitored by the pressure sensor, and the nozzle tip comes into contact with the sample liquid surface and is closed. A liquid level detection step of detecting an increase in the internal pressure of the piping system, and a forced suction step of immediately rotating the pump to return the internal pressure of the piping system to atmospheric pressure immediately after the liquid level detection. It is characterized in.

According to the above construction, the nozzle is lowered while discharging air from above the sample, and when the liquid level of the sample is detected due to an increase in the internal pressure of the piping system, the pump is then operated in reverse. The pump is operated by suction to forcibly return the internal pressure of the piping system to the atmospheric pressure at once. That is,
The internal pressure of the piping system can be forcibly returned to the atmospheric pressure without leaving the nozzle from the liquid surface and without requiring natural evacuation, while keeping the tip of the nozzle in the sample. Although it is necessary to wait for natural pressure equilibrium inside and outside the piping system to simply open the piping system to the atmosphere, according to the present invention, the internal pressure of the piping system can be instantaneously returned to the atmospheric pressure by a forced suction operation. By the way, as a pump,
It is desirable to use one having such a capacity for forced aspiration in addition to the capacity for sample aspiration.

In a preferred aspect of the present invention, immediately after the liquid level detection, a descent stopping step of stopping the lowering of the nozzle and making the tip of the nozzle enter a predetermined depth from the liquid level is provided. Immediately after the above, the lowering stop process and the forced suction process are performed. According to this configuration, due to the liquid level detection, the positioning of the nozzle to the suction start position and the setting of the internal pressure of the piping system to the reference state for sucking the sample are quickly performed.

In a preferred aspect of the present invention, a sample suction step of sucking a sample is performed after the forced suction step. As a result, in a state where the pressurized state of the piping system internal pressure is released and the pressure is returned to the atmospheric pressure, the suction of the sample, that is, the original suction operation is continuously performed.

In a preferred aspect of the present invention, the operation of the pump is temporarily stopped at the time when the internal pressure of the piping system is restored to the atmospheric pressure in the forced suction step,
Thereafter, the sample suction step is performed. That is, in the forced suction step, the internal pressure of the piping system is monitored by, for example, a pressure sensor, and the pump is stopped when the internal pressure reaches (or drops) to or near the atmospheric pressure. Then, after the atmospheric pressure return state is confirmed by the pressure sensor, the sample suction step is performed.

In a preferred aspect of the present invention, the operation amount of a pump required for returning the internal pressure of the piping system to the atmospheric pressure in the forced suction step and the operation amount required for sucking a predetermined amount of the sample are required. The total amount of the operation amount of the pump to be performed is determined, and in the forced suction step and the sample suction step, the pump is continuously suctioned by the total amount of the operation amount, and the forced suction step and the sample suction step are continuously performed. It is done on a regular basis. According to such a configuration, since the suction operation of the pump is not stopped, the dispensing processing speed can be further improved. In addition, the liquid level will drop with the suction of the sample,
In order to keep the distance between the position of the nozzle tip and the liquid level constant, the nozzle is moved down following the liquid level descent. In this case, since the cross-sectional area of the sample container is known, if the suction amount (volume) up to that time is known, the degree of drop of the liquid level can be obtained by calculation. Further, the method according to the present invention provides a method for absorbing a sample.
A nozzle for drawing and discharging, and a pump connected to the nozzle
And the internal pressure of the piping system from the nozzle to the pump
Pressure sensor and moving means for moving the nozzle
In the liquid level detection method for an automatic dispensing device having
Operate the pump to discharge air from the tip of the nozzle.
While lowering the nozzle from above the sample container.
A) When the nozzle is lowered, the pressure
The internal pressure of the piping system is monitored by a sensor, and the nozzle tip
The piping system caused by the blockage coming into contact with the sample liquid surface
A liquid level detecting step of detecting an increase in the internal pressure of the liquid,
Immediately after, the pump is rotated in the reverse direction to
A forced suction step of returning the pressure to atmospheric pressure, and the forced suction step
Subsequently, while continuing the reverse operation of the pump,
And a sample aspirating step of aspirating the sample.
I do . In addition, the apparatus according to the present invention performs the suction and discharge of the sample.
A nozzle to perform, a pump connected to the nozzle,
A pressure sensor that detects the internal pressure of the piping system from the nozzle to the pump
A moving means for moving the nozzle;
Control means for controlling the operation of the pump and the movement of the nozzle,
In the automatic dispensing device having, the control means, the
Operate the pump to discharge air from the nozzle tip
While lowering the nozzle from above the sample container,
When the nozzle descends, it is arranged by the output of the pressure sensor.
Monitors the internal pressure of the pipe system, and the tip of the nozzle contacts the sample liquid surface
We detected an increase in the internal pressure of the piping system by being closed by
And immediately after the liquid level detection, the pump is
To return the internal pressure of the piping system to atmospheric pressure.
You. Further, the apparatus according to the present invention performs suction and discharge of a sample.
Nozzle, a pump connected to the nozzle,
Pressure sensor that detects the internal pressure of the piping system from the spill to the pump
, A moving means for moving the nozzle, and the pump
Control means for controlling the operation of the nozzle and the movement of the nozzle,
In the automatic dispensing apparatus having
Pump to discharge air from the tip of the nozzle.
Then, lower the nozzle from above the sample container, and
When the plunger falls, the output of the pressure sensor
The internal pressure of the system is monitored, and the tip of the nozzle contacts the sample liquid level.
To detect an increase in internal pressure of the piping system due to blockage
Immediately after the detection of the liquid level, the pump is operated in reverse.
To return the internal pressure of the piping system to atmospheric pressure.
Then, continue the reverse operation of the pump.
First, the sample is sucked .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of an automatic dispensing apparatus to which a liquid level detecting method according to the present invention is applied. FIG.
In, a sample 10 to be dispensed is placed in a container 12, and a nozzle 14 dispenses the sample 10. That is, a predetermined amount of the sample 10 is sucked by the nozzle 14, and then the nozzle 14 is moved to discharge the sample 10 by a predetermined amount to another plurality of containers.

The driving section 16 drives the nozzle 14 three-dimensionally. The nozzle 14 is composed of, for example, a metal nozzle base and a plastic disposable tip detachably attached to the tip thereof.
The present invention can be applied not only to such a disposable type nozzle but also to a normal cleaning type nozzle.

The pump 18 comprises a cylinder 20 and a piston 22
, And connected to the nozzle 14 via the air tube 24. That is, the pump 18 changes its internal volume by moving the piston 22 forward and backward, thereby generating a suction force and a discharge force. That is, pressure transmission is performed via the air tube 24, and discharge or suction of the sample is performed by setting the inside of the nozzle 14 to a positive or negative pressure.

The section from the pump 18 to the nozzle 14 via the air tube 24 is called a piping system. Pressure sensor 26
Is for detecting the internal pressure of the piping system. In this embodiment, the internal pressure of the air tube 24 is detected. Control unit 28
Receives the output signal of the pressure sensor 26 and controls the liquid level detection, which will be described later, based on a change in the internal pressure of the piping system. The control unit 28 includes the pump 18 and the driving unit 1.
6 is controlled.

FIG. 2 shows the principle of the liquid level detecting method according to the present invention. The graph of FIG. 2 shows a change in the internal pressure of the piping system detected by the pressure sensor 26,
The horizontal axis indicates time, and the vertical axis indicates pressure.

In FIG. 2, as will be described in detail later, when the nozzle is lowered while discharging a small amount of air from the tip of the nozzle 14 during the period T2, when the tip of the nozzle reaches the liquid level of the sample, As shown in S105 of FIG. 2, the internal pressure of the piping system slightly increases. Therefore, a certain threshold value A is set, and when the detected pressure exceeds the threshold value, the arrival at the liquid level is detected. Up to this point, it is the same as the conventional liquid level detection method.

Immediately after the liquid level is detected, in this embodiment, the operation of the pump is reversed to switch the discharge operation to the suction operation, and as shown by a solid line 100 in FIG. The internal pressure is restored to the atmospheric pressure at a stretch. Thereafter, the sample is sucked as usual.

As described above, instead of waiting for the return to the natural atmospheric pressure by opening the air release valve, the pump is reversely operated to forcibly return the internal pressure of the piping system to the atmospheric pressure, so that quick recovery is possible. Dispensing processing becomes possible. The time of the reverse operation or the stroke of the piston may be performed until the atmospheric pressure is detected by the pressure sensor 26, but the time or the stroke amount is obtained in advance, and when the liquid level is detected. The reverse operation may be automatically performed by a predetermined amount. In any case, if the internal pressure of the piping system is positively returned to the atmospheric pressure by reversing the operation of the pump, preparation for suction can be achieved more quickly than in the past.

Next, a liquid level detecting method according to the present embodiment will be described with reference to FIG.

In S101, the piston 22 of the pump 18 shown in FIG. 1 is pulled, and air is sucked into the pump.
That is, preparation for performing an air discharge operation in a later step.

Next, in S102, the driving unit 1 shown in FIG.
The nozzle 14 is conveyed by 6 and the nozzle 14 is positioned above the sample 10 to be dispensed.

In S103, the nozzle 14 is lowered, and at the same time, the discharge of air from the tip of the nozzle 14 is started (see S103 in FIG. 2).

Then, while the nozzle descends and the air is discharged, in S104, after a lapse of a predetermined time T1 from S103, the internal pressure of the piping system is sampled by the pressure sensor 26 as a reference pressure value. In FIG. 2, the reference pressure value serves as a reference for setting a threshold value A for liquid level detection. In this way, by sampling the reference pressure value during the descent of the nozzle, the reference pressure value is detected. Accuracy can be increased. That is, it is possible to capture a reference pressure value that reflects pressure fluctuations caused by air pressure at the tip of the nozzle due to nozzle lowering, ambient temperature, and the like.

In S105 of FIG. 3, after S104, the internal pressure of the piping system is constantly monitored by the pressure sensor 26, and when the internal pressure of the piping system exceeds the threshold A, it is determined that the liquid level has been detected. That is, when the nozzle tip comes into contact with the liquid surface and the tip opening is closed, air cannot be discharged. As a result, the internal pressure of the piping system slightly increases, and the pressure increase is set to a threshold. A is used to detect the liquid level, thereby achieving liquid level detection. Almost simultaneously with the detection of the liquid level, the discharge of the air is stopped in S106 of FIG. At this time, the nozzle tip stops when it enters, for example, 2 mm from the liquid level. If the nozzle enters too deeply, a large amount of sample will adhere to the outer surface. Therefore, the position of the nozzle for sucking the sample should be closer to the liquid surface unless bubbles are generated.

The above operation is the same as the conventional operation, but in this embodiment, as shown in S107 in FIG. 3, the pump 18 in FIG. That is, for example, instead of opening the air release valve to return the internal pressure of the piping system to the atmospheric pressure naturally, in this embodiment, the air in the piping system is forcibly sucked and the internal pressure of the piping system is instantaneously reduced to the atmospheric pressure. It is a thing to return. It is desirable that the air suction time T3 (see FIG. 2) in S107 be set in advance based on an experiment or the like. As a modification, the reverse rotation operation of the pump can be stopped when the atmospheric pressure is confirmed. . However, considering the pressure transmission of the air, if the pump is stopped when the atmospheric pressure is confirmed, the internal pressure of the piping system will be maintained at a negative pressure rather than the atmospheric pressure. It is desirable to stop the reverse rotation operation. From such an idea, T in FIG.
3 times are set.

At S108 in FIG. 3, the atmospheric pressure is confirmed by the pressure sensor 26. When the atmospheric pressure is not confirmed due to some trouble, for example, an alarm may be output to notify the operator.

In S109 of FIG. 3, after the atmospheric pressure is confirmed, the sample is actually sucked. In particular,
The inner volume of the pump 18 is increased by further withdrawing the piston 22 of the pump 18, whereby the nozzle 1
The sample 10 is suctioned by setting the inside of the sample 4 to a negative pressure. The suction amount of the sample can be appropriately set according to the stroke amount of the piston 22. T4 shown in FIG. 2 indicates the operation time of the pump 18 for aspirating the sample.

Then, in S110 of FIG. 3, after the sample is sucked, the nozzle is raised, and the same dispensing as in the related art is performed. Then, if necessary, replacement of the disposable chip, cleaning of the nozzle, etc., are performed,
Are performed.

S111 in FIG. 3 is another embodiment,
This step is performed after step 106, and is a step of continuously performing the air suction shown in S107 and the sample suction shown in S109. In FIG. 2, a waveform 102 indicating the continuous suction is shown by a broken line. As shown by the broken line 102, in S107 and S109 shown in FIG. 3, when focusing on the operation of the pump, both are suction operations, and there is no difference in the meaning. Therefore, a waveform when the air suction and the sample suction are continuously performed is S102 in FIG. In this case, although the return to the atmospheric pressure is not confirmed, there is an advantage that the dispensing process can be performed more quickly. When such a continuous suction is performed, the pump stroke may be operated at a stroke by adding the piston stroke amount in S107 and the piston stroke amount in S109 and adding the added stroke amount. T5 shown in FIG. 2 indicates the operation time of the pump 18 in which such continuous suction is performed.

In FIG. 2, since a predetermined amount of the sample is contained in the nozzle 14 after the sample is sucked, the internal pressure of the piping system is maintained at a slightly negative pressure due to its own weight.

FIG. 4 shows the position of the piston when starting the suction of the sample in comparison with the conventional position. In the conventional example shown in FIG. 2A, the case where an atmospheric pressure release valve is used is shown. That is, the time when the liquid level detection is performed while discharging the air and the piston is stopped is 200 in FIG. It is shown. The position of the piston after aspirating the sample from this state is indicated by 202.

On the other hand, in the present invention shown in (B), as described above, even when the position of the piston is the same as the conventional one at the end of the air discharge for detecting the liquid level, the forced air suction is performed as described above. Therefore, the position of the piston at the time of starting the suction of the sample is the position indicated by 204. That is, V in FIG.
As shown in FIG. 1, the suction of the sample is started after a certain amount of air is sucked. Therefore, as shown by 206 in FIG. 4, when the same amount of sample is sucked, the position of the piston that finally stops is a position that is more retracted than in the past.
Therefore, in this embodiment, the pump 18 which uses a larger capacity than the conventional one based on such conditions is used. Specifically, as shown by V2 in FIG. 4, a cylinder 20 larger by a certain volume than the conventional one is used. That is, the capacity of the pump is set in anticipation of the air suction in S107.

The nozzle 14 is also lowered because the liquid level is lowered with the suction of the sample. That is, since the volume of the sample taken into the nozzle 14 is calculated from the stroke amount of the piston 22, and on the other hand, since the cross-sectional area of the container 12 is known, the descending amount of the liquid level is calculated from the suction amount. The nozzle 14 is lowered according to the amount of the lowering.

[0042]

As described above, according to the present invention, in the automatic dispensing apparatus, after the air is discharged from the tip of the nozzle to detect the liquid level, the piping system can be quickly formed without generating bubbles. By returning the internal pressure to the atmospheric pressure, the dispensing speed can be improved as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an automatic dispensing apparatus to which a liquid level detection method according to the present invention is applied.

FIG. 2 is a diagram showing a change in internal pressure of a piping system in liquid level detection.

FIG. 3 is a flowchart illustrating a liquid level detection method according to the present invention.

FIG. 4 is an explanatory view showing the position of a piston at the start of suction of a sample.

[Explanation of symbols]

10 samples, 14 nozzles, 18 pumps, 26 pressure sensors, 28 control units.

Continuation of the front page (56) References JP-A-7-103987 (JP, A) JP-A-63-109330 (JP, A) JP-A-2-196964 (JP, A) JP-A 8-114605 (JP) JP-A-7-287021 (JP, A) JP-A-6-109603 (JP, A) JP-A-3-214058 (JP, A) JP-A-5-60768 (JP, A) 4-252960 (JP, A) Japanese Utility Model 63-175864 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 23/14 G01N 35/10

Claims (8)

(57) [Claims] A nozzle for sucking and discharging a sample; a pump connected to the nozzle; a pressure sensor for detecting an internal pressure of a piping system from the nozzle to a pump; a moving unit for moving the nozzle ; In the liquid level detection method of the automatic dispensing device having an air discharge lowering step of lowering the nozzle from above the sample container while discharging air from the tip of the nozzle by performing the discharging operation of the pump, A liquid level detecting step of monitoring the internal pressure of the piping system by the pressure sensor, and detecting an increase in the internal pressure of the piping system due to the nozzle tip contacting and closing the sample liquid surface; Immediately after the detection, a step of forcibly returning the internal pressure of the piping system to the atmospheric pressure by reversing the operation of the pump, and a method of detecting a liquid level in the automatic dispensing apparatus. 2. The liquid level detection method according to claim 1, further comprising a descent stop step of stopping descent of the nozzle immediately after the detection of the liquid level and causing the tip of the nozzle to enter a predetermined depth immediately below the liquid level. A liquid level detecting method for an automatic dispensing apparatus, wherein the lowering stop step and the forced suction step are performed by the liquid level detection. 3. The liquid level detection method for an automatic dispensing device according to claim 1, wherein a sample suction step of sucking a sample is performed after the forced suction step. 4. The liquid level detecting method according to claim 3, wherein in the forced suction step, the operation of the pump is temporarily stopped when the internal pressure of the piping system is restored to the atmospheric pressure, and thereafter, the sample suction step is executed. A liquid level detecting method for an automatic dispensing device. 5. The liquid level detecting method according to claim 3, wherein in the forcible suction step, an operation amount of a pump required for returning the internal pressure of the piping system to the atmospheric pressure and a predetermined amount of the sample are sucked. The total sum of the required operation amounts of the pumps is determined. In the forced suction step and the sample suction step, the pump is continuously operated by the total sum of the operation amounts to perform the forced suction step and the sample suction step. The liquid level detection method of the automatic dispensing device, wherein the steps are performed continuously. 6. A nozzle for sucking and discharging a sample, a pump connected to the nozzle, and a pressure for detecting an internal pressure of a piping system from the nozzle to the pump.
In the liquid level detecting method for an automatic dispensing device having a force sensor and a moving unit for moving the nozzle, air is discharged from a nozzle tip by discharging the pump.
While lowering the nozzle from above the sample container
In the air discharge lowering step and the lowering of the nozzle, piping is performed by the pressure sensor.
The internal pressure of the system is monitored, and the tip of the nozzle contacts the sample liquid level.
To detect an increase in internal pressure of the piping system due to blockage
A liquid level detecting step to be performed, and immediately after the liquid level detection,
A forced suction step of returning the internal pressure of the piping system to atmospheric pressure, and, following the forced suction step, a reverse operation of the pump.
Liquid level detection in an automatic dispensing apparatus , which comprises:
Method. 7. A nozzle for sucking and discharging a sample, a pump connected to the nozzle, and a pressure for detecting an internal pressure of a piping system from the nozzle to the pump.
Force sensor, moving means for moving the nozzle, control for controlling operation of the pump and movement of the nozzle
In the automatic dispensing device having means, wherein the control means, the discharge air from the nozzle tip by discharge operation of the pump
While the nozzle is lowered from above the sample container, and when the nozzle is lowered, the output of the pressure sensor is used.
To monitor the internal pressure of the piping system, and the nozzle tip
Increase in internal pressure of the piping system due to contact and blockage
Detects, immediately after the liquid level detection, previous reverse by operating the pump
Automatic, characterized by returning the internal pressure of the piping system to atmospheric pressure
Dispensing device. 8. A nozzle for sucking and discharging a sample, a pump connected to the nozzle, and a pressure for detecting an internal pressure of a piping system from the nozzle to the pump.
Force sensor, moving means for moving the nozzle, control for controlling operation of the pump and movement of the nozzle
In the automatic dispensing device having means, wherein the control means, the discharge air from the nozzle tip by discharge operation of the pump
While the nozzle is lowered from above the sample container, and when the nozzle is lowered, the output of the pressure sensor is used.
To monitor the internal pressure of the piping system, and the nozzle tip
Increase in internal pressure of the piping system due to contact and blockage
Detects, immediately after the liquid level detection, previous reverse by operating the pump
The internal pressure of the piping system is returned to the atmospheric pressure, and the reverse operation of the pump is performed following the forced suction step.
While aspirating the sample
Automatic dispensing device.