JPH0411259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid suction and discharge pipette used for dispensing liquid from a liquid sample.

In general, it is often necessary to chemically analyze liquid samples, including body fluids from the human body. Dry methods and wet methods are known as chemical analysis methods for liquid samples. Of these, the dry method is simpler than the wet method in that it does not require preparation steps such as diluents. be. This dry method involves dropping the liquid sample to be analyzed into a liquid sample analysis element, which consists of a thin layer body impregnated with a specific reagent sandwiched between mounts, to combine the reagent in the liquid sample analysis element with the liquid sample. react, and the progress or result of the reaction,
For example, this is a method in which a color change due to a reaction is examined using an optical analysis device or the like, and thereby the presence or absence or amount of a specific component in a liquid sample can be determined.

In such analysis, a liquid suction and discharge pipette is used to dispense liquid from a liquid sample, and this pipette has a structure similar to a syringe, and has a liquid suction and discharge part at the end. It consists of a cylinder, a piston provided in the cylinder, and a driving means for moving the piston. By moving the piston, liquid is sucked in and discharged.

Conventionally, known driving means for moving the piston include manual means, means using a suction pump, and mechanical means using a pinion and rack.
However, manual means have poor work efficiency, and means such as a suction pump tend to cause variations in the suction amount, especially when the amount of liquid sample to be dispensed is required to be an appropriate predetermined amount. This results in poor dispensing accuracy. Mechanical means such as pinions and racks also have the disadvantage of being complicated and large in size.

The present invention has been developed based on the above-mentioned circumstances, and is capable of automatically suctioning and discharging liquid, has a simple and compact structure, and can control the amount of suction and discharge with high precision. It is an object of the present invention to provide a pipette for inhaling and discharging liquid that can be used to dispense a constant amount of liquid.

In the first invention of the present application, a cylinder having a liquid suction and discharge part at one end, a piston provided to reciprocate in this cylinder in an airtight manner, and a piston at the other end of the cylinder. The piston includes a coil mounting frame and a piston driving coil fixedly provided within the coil mounting frame, and an end of the piston is inserted into the piston driving coil to form a driving core. A stopper is provided at a proximal end of a protruding portion of the piston that protrudes into the coil mounting frame, and a suppressing member that applies an elastic force in a direction that causes the driving core to protrude from within the piston driving coil is combined with the stopper. It is characterized in that it is provided between the piston drive coil and the piston drive coil.

Further, in the second invention of the present application, a cylinder having a liquid suction and discharge portion at one end, a piston provided to reciprocate in this cylinder in an airtight manner, and the other end of the cylinder. a coil mounting frame provided in the section; a plurality of piston drive coils fixedly provided in the coil mounting frame so as to line up along the length direction of the cylinder; The piston is characterized in that it comprises a driving core fixedly provided to the piston so as to pass through the piston in sequence.

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

FIG. 1 is an explanatory diagram showing an embodiment of the first invention.

A liquid suction and discharge section 2 is provided at one end 11 of the cylinder 1, and a cylindrical coil mounting frame 4, for example, is integrally provided at the other end 12.

The piston 3 has a rod-like shape, for example, so as to reciprocate airtightly within the cylinder 1, and its tip 31 is located within the liquid intake/discharge portion 2 of the cylinder 1.

A cylindrical piston drive coil (hereinafter referred to as a "coil" as appropriate) 6 is fixedly provided within the coil mounting frame 4 .

The rear end 32 of the piston 3 is inserted into the coil 6 to constitute a driving core.

An iron core 5 as a stopper is provided at the base end of the protrusion 33 of the piston 3 that protrudes into the coil mounting frame 4. This iron core 5 has a disk-like form and is fixed to the piston 3 so as to be coaxial therewith.

In the coil mounting frame 4, for example, a return spring 7, which serves as a suppressing member that applies an elastic force in a direction that causes the rear end 32 of the piston 3, which is a driving core, to protrude from inside the coil 6, connects the iron core 5, which is a stopper, and the coil. 6.

A driving power source (not shown) is connected to the coil 6.

The pipette tip 8 is removably fitted into the liquid suction and discharge portion 2 in an airtight manner.

According to such a configuration, a liquid sample is dispensed as follows.

That is, when the coil 6 is demagnetized, the iron core 5 is in contact with the front wall of the coil mounting frame 4 due to the elastic force of the return spring 7.
In this state, the tip of the pipette tip 8 is placed into the liquid sample.

Next, when the coil 6 is excited, this coil 6
The magnetic force generated in the drive core (rear end 32 of the piston 3) resists the elastic force of the return spring 7.
moves in the suction direction, the tip 31 of the piston 3 moves backward, creating negative pressure within the liquid suction and discharge section 2, and the liquid sample is suctioned into the pipette tip 8.

Next, while maintaining this state, for example, an analytical element is placed directly under the pipette tip 8 by appropriate means, and when the coil 6 is demagnetized, the attraction force by the coil 6 disappears and the return force acting on the iron core 5 is removed. The elastic force of the spring 7 causes the piston 3 to move forward until the iron core 5 comes into contact with the front wall of the coil mounting frame 4, that is, until it returns to its original position, thereby sucking the liquid into the suction and discharge section 2. The liquid sample that had been stored is discharged to the outside and dripped into the analysis element.

According to the embodiment shown in FIG. 1, by energizing and demagnetizing the coil 6, suction and discharge of a liquid sample can be performed automatically. The configuration is simpler and more compact than that in the case of using.

Since the moving distance of the piston 3 is reliably made constant by the iron core 5, it is possible to always keep the suction amount and the discharge amount of the liquid sample constant.

In addition, when sucking a liquid sample, the rear end 32 of the piston 3 is sucked into the coil 6 against the elastic force of the suppressing member 7 acting on the iron core 5, so the movement of the piston 3 becomes smooth and the suction is carried out without difficulty, and from this point of view, the accuracy of the inhaled amount is further improved.

FIG. 2 is an explanatory diagram showing an embodiment of the second invention.

A liquid suction and discharge section 2 is provided at one end 11 of the cylinder 1, and a cylindrical coil mounting frame 4, for example, is integrally provided at the other end 12.

The piston 3 has a rod-like shape, for example, so as to reciprocate airtightly within the cylinder 1, and its tip 31 is located within the liquid intake/discharge portion 2 of the cylinder 1.

Two piston drive coil groups (hereinafter referred to as "coil groups") 6A and 6B are fixedly provided within the coil mounting frame 4.

The first coil group 6A is composed of a plurality of cylindrical piston drive coils (hereinafter referred to as "coils" as appropriate) 61A to 64A, which are fixedly provided so as to be lined up along the length direction of the cylinder 1. has been done.

The second coil group 6B is similarly composed of a plurality of cylindrical piston drive coils (hereinafter referred to as "coils" as appropriate) 61B to 64B.

Disc-shaped iron cores 51 and 52, which serve as drive cores, are fixed to the base end and other end 32 of the protrusion 33 that protrudes into the coil mounting frame 4 of the piston 3, respectively, so as to be coaxial with the piston 3. These iron cores 51 and 52 sequentially pass through the coils 61A to 64A and 61B to 64B in the first coil group 6A and the second coil group 6B, respectively.

The operations of the first coil group 6A and the second coil group 6B are controlled by a control mechanism (not shown).

The first coil group 6A includes electrically independent coils 61A and 6, which are arranged adjacent to each other along the length direction of the piston 3.
2A, a coil 63A, and a coil 64A, the second coil group 6B includes electrically independent coils 61B, 62B, It is composed of a coil 63B, a coil 64B, and a coil 65B. The relative positional relationship between the first coil group 6A and the second coil group 6B and the iron core 51 and the iron core 52 is, for example, in the state shown in FIG. 2, that is, when the iron core 52 is located inside the coil 61B. The iron core 51 is shifted to the right side of the coil 61A, and when the iron core 51 is moved from this state and positioned inside the coil 61A, the iron core 52 is shifted to the right side of the coil 62B, iron core 5
When the piston 3 is moved further and placed in the coil 62B, the iron core 51 is shifted to the right side of the coil 62A. A state in which the iron core 52 is sequentially located within each coil of the first coil group 6A and a state in which the other iron core 52 is sequentially located within each coil of the second coil group 6B are set to appear alternately. A section 13 separates the first coil group 6A and the second coil group 6B, and also serves as a stopper for the iron core 51 and the iron core 52.

The control mechanism is, for example, as shown in FIG.
Coils 61A to 64A and coils 61B to 65B
A driver (amplifier) 111 connected to each of the
~114 and 121-125, and drivers 111-114 and 121 depending on the combination of input signals.
A decoder 20 that supplies a drive signal to a selected one of the circuits 125, a counter 21 that supplies an input signal to this decoder 20, a pulse generator 22 that supplies clock pulses to this counter 21, a flip-flop circuit 23, and an AND A circuit 24;
The flip-flop circuit 25 supplies an up-down signal to the counter 21, 26 is an AND circuit, and 27 and 28 are switches.

According to such a configuration, a liquid sample is dispensed as follows. That is, in the control mechanism, when the switch 27 is first turned on, a reset signal is sent to the counter 21, and the iron core 52 is placed in the coil 61B at a predetermined position (hereinafter referred to as the "reset position"). A drive signal is supplied from the decoder 20 to the driver 121 so that the coil 61B is moved to a certain position.
is excited, which causes the iron core 52 to connect to the coil 61B.
the reset position. At this time, the other iron core 51 is shifted to the right side of the coil 61A. In this state, when the tip of the pipette tip 8, which is airtightly fitted and attached to the tip of the liquid suction and discharge part 2, is put into the liquid sample, the switch 28 is turned on and the counter 21 is placed in a state shown in FIG. Clock pulses are provided. According to the number of clock pulses, coil 61A, coil 62B, coil 62
A, coil 63B, coil 63A, coil 64
B, the coil 64A and the coil 65B are excited in this order for a certain period of time determined by the period of the clock pulse, and as a result, the iron core 51 and the iron core 5
2 are attracted and moved to the left side so that they are placed alternately in each coil. To explain in detail, the coil 61A is excited at the same time as the coil 61B is demagnetized, thereby canceling the magnetic force acting on the iron core 52 and pulling the iron core 51 into the coil 61A due to the magnetic force generated in the coil 61A. The iron core 51 is moved to the left side. Next, coil 61
At the same time as A is demagnetized, the coil 62B is excited, thereby canceling the magnetic force acting on the iron core 51, and the magnetic force generated in the coil 62B attracts the iron core 52 into the coil 62B. 5
2 is further moved to the left side. Thereafter, each coil is similarly demagnetized and excited in the above-mentioned order and moved until the suction completion position, that is, the iron core 52 is located within the coil 65B. As the iron cores 51 and 52 are alternately moved to the left in this way, the piston 3 is simultaneously moved, so negative pressure is generated within the liquid suction and discharge section 2, which causes pressure inside the pipette tip 8. A liquid sample is aspirated. However, the coil 65B is not demagnetized immediately, but is kept in an excited state until the discharge standard for the sucked liquid sample is established.

Next, for example, an analytical element is placed directly under the pipette tip 8 by an appropriate means, and when preparation for dispensing is completed, the order is completely reversed to that described above: coil 65B, coil 64A, coil 64B, coil 63A, coil 63B, coil 62A, coil 6
2B, the coil 61A, and the coil 61B are repeatedly demagnetized and excited in this order, and as a result, the iron core 51 and the iron core 52 are alternately moved in the opposite direction to that described above, that is, to the right side. are moved to the right side at the same time, so that the liquid sample in the pipette tip 8 is discharged, and the liquid sample is dripped and supplied to the analytical element.

According to this embodiment, the movement of the piston 3 is performed by the magnetic force generated in the coils 61A to 64A and the coils 61B to 65B. A suction pump, a rack, a pinion, an electric motor, etc. are not required, so the structure is simple, and the coils and iron cores 51, 52 can be designed to be compact, so that the overall structure can be made more compact. Since a plurality of coils are provided, the piston 3 is also moved in the direction of discharging the liquid sample by the magnetic force of the coils by excitation and demagnetization of the coils in the reverse order of excitation and demagnetization of the coils when sucking the liquid sample. be able to. Since the iron core 51 or 52 is reliably positioned within the energized coil, the moving distance of the piston 3 is changed from the reset position where the iron core 52 is within the coil 61B to the position where the iron core 52 is within the coil 65B. This becomes a constant value until a certain suction completion position, and therefore, it is possible to always keep the suction and discharge amount of the liquid sample, which is determined according to the moving distance of the piston 3, constant with high accuracy. In the above embodiment, all the coils 61A to 64A and 61B to 65B are energized to move the piston 3 to the maximum extent.
By appropriately selecting the coil to be excited, the suction completion position can be changed and the moving distance of the piston 3 can be changed, and thereby the suction and discharge amount of the liquid sample can be changed as necessary. Further, two coil groups, a first coil group 6A and a second coil group 6B, are provided, and an iron core 51 and an iron core 52 are provided corresponding to each of these coil groups 6A and 6B. The separation distance between the cores 52 is set so that when one of the iron cores 51 and 52 is located within the coil, the other is positioned offset from the other coil, so that the piston 3 Since the piston 3 moves gradually by small distances, the movement of the piston 3 becomes smooth, and the suction and discharge of the liquid sample is carried out smoothly, thereby further increasing the accuracy of the amount of suction and discharge.

In the above, the number of coils may be determined as necessary, but for example, if a large number of coils are provided and the coils to be energized and demagnetized can be appropriately selected depending on the type of dispensing process, the amount of suction and discharge can be increased. This has the advantage that it is possible to appropriately select the parameters over a wide range. Further, by providing a large number of coils having a small width, the movement of the piston 3 can be made even smoother.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be modified in various ways. For example, the coil may be provided on the outer periphery of the coil mounting frame, and in this case, the coil mounting frame may be formed of a non-magnetic material with a small outer diameter. As the material of the core, any material other than iron can be used as long as it has magnetism. Further, the widths of the respective coils may be the same or different, and the number of sets of coil groups and cores may be three or more sets or one set.

As described above, according to the present invention, liquid can be automatically sucked and discharged, has a simple and compact structure, and can be sucked and discharged at a constant amount with high precision. An inhalation and exhalation pipette can be provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of the invention, FIG. 2 is an explanatory sectional view showing another embodiment of the invention, and FIG. 3 is an explanatory sectional view showing another embodiment of the invention. Explanatory block diagram showing an example of the control mechanism, No. 4
The figure is an explanatory diagram showing the operation of the control mechanism shown in FIG. 3. 1...Cylinder, 2...Liquid suction and discharge part, 3...
...Piston, 4...Coil mounting frame, 5...Iron core,
6... Coil, 7... Return spring, 8... Pipette tip, 6A... First coil group, 6B...
...Second coil group, 61A, 62A, 63A, 6
4A...Coil, 61B, 62B, 63B, 64
B, 65B...Coil, 51, 52...Iron core, 1
3...Division, 111, 112, 113, 11
4,121,122,123,124,125...
... Driver, 20 ... Decoder, 21 ... Counter, 22 ... Pulse generator, 23, 25 ... Flip-flop circuit, 24, 26 ... AND circuit, 27, 28 ... Switch.

Claims (1)

[Claims] 1. A cylinder having a liquid suction and discharge portion at one end; a piston provided to reciprocate in this cylinder in an airtight manner; and a piston provided at the other end of the cylinder. comprising a coil mounting frame and a piston driving coil fixedly provided within the coil mounting frame, an end of the piston being inserted into the piston driving coil to constitute a driving core; A stopper is provided at a proximal end of a protruding portion of the piston that protrudes into the coil mounting frame, and a suppressing member that applies an elastic force in a direction that causes the driving core to protrude from within the piston driving coil is connected between the stopper and the piston. A pipette for sucking and discharging liquid, characterized in that it is provided between a drive coil and a drive coil. 2. A cylinder having a liquid suction and discharge portion at one end, a piston provided to reciprocate in this cylinder in an airtight manner, and a coil mounting frame provided at the other end of the cylinder, a plurality of piston drive coils fixedly provided in a coil mounting frame so as to be lined up along the length direction of the cylinder; and fixed to the piston so as to pass sequentially through the plurality of piston drive coils. A pipette for inhaling and discharging liquid, characterized in that it comprises a driving core provided with a drive core.