JPS6250783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for weighing a variable predetermined amount of a minute amount of liquid, and particularly to a device suitable for use in a sample minute amount weighing device in a clinical automatic analyzer.

Conventionally, this type of device uses a weighing device using a microsyringe or a rotary valve in which a hole of a predetermined volume is formed and the valve is rotated to cut off the liquid to be weighed and weigh a predetermined amount of liquid. There is a device.

Weighing devices using microsyringes are most commonly used due to their simple configuration, but weighing errors increase over time due to liquid suction loss due to wear of the packing between the syringe and the plunger, and Weighing errors may occur due to the generation of air bubbles due to the depressurization of the suction liquid during suction into the
There are drawbacks such as errors in the amount of liquid dispensed depending on the size of the droplets generated at the tip of the dispensing tube, and solid matter such as fibrin clogging the syringe inlet/outlet, which may impede the operation of the microsyringe.

On the other hand, although the valve cut method has better accuracy and reproducibility of the weighed amount than the microsyringe,
When introducing the liquid to be weighed into the weighing hole, it is necessary to cut the valve with the pipes on the upstream and downstream sides of the weighing hole filled with the liquid to be weighed, which takes a considerable amount of time. Generates a wasteful amount. Particularly in the field of clinical chemistry analysis, this sample fluid is serum from precious blood collected from patients whose blood collection volume is limited, so the fact that a large amount is wasted is a serious drawback. It can be said that there is. Furthermore, bubbles are generated due to the depressurizing effect when the liquid to be weighed is sucked up to the valve portion, causing an error in the amount to be weighed. Furthermore, the accuracy of setting the volume of the weighing hole is poor due to the difficulty of machining and finishing when forming the weighing hole. In particular, after long periods of use, shavings of packing material, such as Teflon (tetrafluoroethylene resin), may adhere to the opening of the weighing hole, changing the effective volume of the weighing hole or causing liquid It may make the flow worse.

In view of the above points, a new liquid microweighing device that eliminates these drawbacks is disclosed in Patent Application No. 19725 filed in 1972 by the same applicant as the present application.
No. 53-104292). This device is
A weighing groove is formed on the circumferential surface near the lower end of a cylindrical body, and the groove is liquid-tightly sealed or opened with a sleeve that fits snugly into the cylindrical body and can slide in the axial direction of the cylindrical body. There is a device in which a predetermined amount of liquid is measured using the groove.

This invention is a further development of the above-mentioned liquid micro-amount weighing device, and an object of the present invention is to provide a device capable of appropriately converting a plurality of different weighing amounts.

The present invention will be explained in detail below based on the drawings.

In the figure, a holding member 2 is held by a generally well-known means so as to be movable up and down and rotatable or slidable on a base body (not shown). Holding member 2
The support block 4 is held and fixed at its flange portion 6. A rotating member 10 is rotatably supported on the support block 4 by a ring 8 on its peripheral surface. The circumferential surface of the rotating member is coated with Teflon or the like to reduce friction. Rotating member 1
A plurality of circular openings are provided at appropriate intervals on the circumference at a predetermined distance from the central axis of 0, and each opening has a cylindrical body having a weighing groove of a different volume. and a weighing unit 1 equipped with a sleeve, etc. for sealing and opening the weighing groove thereof.
2 is fixed. The configuration of each weighing unit is the same except for the difference in the volume of the weighing groove, so the following
This section explains the two units.

A first cylinder 18 is fixed to the opening of the rotating member 10 at a flange portion 20 formed above the first cylinder 18 with screws. A rotating cylindrical body 28 is held inside the cylinder 18 via bearings 30 and 32. A magnet holder 35 to which a magnet 34 constituting a magnet pair is fixed is fixed to the upper end of the cylindrical body 28, and a first motor 36 is attached to this.
The other magnet 38 of the magnet pair driven by the magnet is magnetically coupled.

A weighing shaft 40 is removably screwed onto the lower end of the cylindrical body 28. A weighing groove 42 having a constant volume is formed on the circumferential surface of the weighing shaft 40. In the figure, the groove 42 is formed to be inclined with respect to a plane perpendicular to the axis of the cylindrical body 28, but its shape is not limited to this and can take various shapes. For example, the groove 42 may or may not be continuous in a closed loop. It may be spiral-shaped, or it may be similar to a concave shape. It is preferable that this cylinder act as a stirring bar when rotated, so the grooves may be inclined, have a continuously varying depth, or have a spiral shape so that the cylinder does not evaporate liquid. Preferably, it imparts agitation to the liquid when immersed therein and rotated. Forming the groove 42 in such a shape also has the effect of diffusing the liquid to be weighed that remains in the groove into the immersion liquid by the rotation of the rotating cylindrical body 28.

A screw 44 is formed on the outer peripheral surface of the first cylinder 18, and a second cylinder 46 is screwed onto this screw. A flange 48 is provided at the upper end of the cylinder 46.
One or more notches 50 are formed into which are engaged downwardly projecting locking pins 54 fixed to spur gears 52 pivoted on the first cylinder 18 . The gear 52 meshes with a gear 58 fixed to a rotating shaft 57 driven by a second motor 56. The rotating shaft 57 is pivotally supported by a bearing 55. That is, a gear (not shown) directly fixed to the rotating shaft of the motor 56 meshes with a gear 59 fixed to the rotating shaft 57. When the gear 52 is rotated by the motor 56, the second cylinder 46 is rotated via the pin 54, so that the second cylinder 46 is rotated by the motor 56.
6 moves axially relative to the first cylinder 18 with which it is screwed. If the motor 56 is reversed, the cylinder 46 will move in the opposite direction.

An annular protrusion 60 is formed on the central inner wall of the second cylinder 46, and a spring 62 is located in the space below the annular protrusion 60. This spring is compressed against the protrusion 60 by a third cylinder 64. The third cylinder 64 is supported by a cap nut 66 screwed onto a screw provided on the outer periphery of the lower end of the second cylinder 46 . A space 68 is formed above the third cylinder 64 to allow this cylinder to move upwardly relative to the second cylinder 46 against the force of the spring 62. A fourth cylinder 72 is rotatably held inside the third cylinder 64 via a bearing 70. However, the fourth cylinder 72
cannot move axially relative to the third cylinder 64. The lower part of the fourth cylinder 72 is provided with a sleeve 74 that is in close contact with the weighing shaft 40 so as to be slidable in the axial direction thereof. Although the figure shows the state in which the weighing groove 42 is sealed, when this groove is opened and the weighing shaft 40 is immersed in the liquid and the sleeve 74 is moved downward, the lower end of the sleeve 74 has a step on the weighing shaft. The groove 42 is liquid-tightly sealed by contacting the portion 78, so that the liquid sealed within the groove will not leak to the outside. The lower surface 80 of the weighing shaft 40 is a conical surface.
This is adapted to the case where the inner bottom of the container containing the liquid to be weighed has a funnel-shaped shape, and allows the liquid to be weighed to be weighed with as little waste as possible. The rotating cylindrical body 28 has a vertical groove 82 formed in the axial direction on the lower peripheral surface, and a pin 84 fixed to the fourth cylinder 72 is engaged with this vertical groove, so that the fourth cylinder 72 is connected to the rotating cylindrical body 28. It cannot be rotated, but it can be moved in the axial direction.

The weighing shaft 40 is rotated together with the sleeve 74 via the magnet pair 34, 38 and the rotating cylindrical body 28 by driving the first motor 36. The sleeve 74 is moved up and down by the drive of the second motor 56. That is, when the second motor 56 is driven, the gears 59, 58 and 52 and the pin 5
Since the second cylinder 46 is rotated via 4,
The second cylinder 46 is connected to the first cylinder 18 , that is, the rotating cylindrical body 28 by the action of the screw 44 .
It is moved up and down while rotating together with the cylinder 64. As a result, the fourth cylinder 72 moves up and down together with the third cylinder 64, but does not rotate due to the action of the bearing 70 and pin 84. This vertical movement of the fourth cylinder 72 corresponds to the vertical movement of the sleeve 74.

The rotating member 10 has a rotating shaft 57 at its center with a bearing 8.
It is pivoted at 8,88. The rotating member 10 also has a spur gear 90 at its upper end, which is a third
It meshes with a gear 94 fixed to the rotating shaft of a motor 92. The third motor 92 is a pulse motor and is adapted to accurately stop each weighing unit 12 when it reaches a predetermined position. Note that instead of the pulse motor, a position detection mechanism may be used to stop the rotating member 10 at a predetermined position.

According to the liquid microweighing device according to the present invention described above, the weighing shaft 40 can be made of metal or synthetic gemstones with extremely low wear, such as sapphire or ruby, so that the deterioration of weighing accuracy over time is extremely small. small. In addition, since the weighing groove 42 is formed on the outer circumferential surface of the weighing shaft, it is easy to grind, polish, etc., and as a result, a good finish is obtained, so it is difficult to get dirty and does not require rotary cleaning. Dirt can be easily removed. Since the weighing groove is on the outer periphery, it is easy to wipe off dirt with a soft material such as a sponge. Furthermore, since the weighing device of the present invention does not use a pump, there is no reduction in pressure, and as a result, there is no possibility that air bubbles will be generated and reduce the weighing accuracy. Note that when the weighing shaft is immersed in the liquid to be weighed, it can be rotated to blow away air bubbles anchored in the groove, so that weighing errors due to air bubbles can be reliably avoided. In addition, because of the good surface finish and ease of cleaning, as mentioned above, there is almost no adhesion of solid substances such as fibrin to the grooves, and a good weighing device can be obtained. No incidents of conduit-based devices causing conduit clogging occur.

A particularly important advantage of this invention is that the metered amount of trace liquid can be varied. Particularly in automatic chemical analyzers, it is necessary to change the amount of sample to be weighed, which is the liquid to be weighed, because the analytical items are semi-fixed in multi-method devices that require multi-item analysis. , although relatively few, 1
It is said to be an essential specification condition for a two-channel automatic analyzer, and by adding such a mechanism, it is possible to perform a far wider range of inspection items than with fixed conventional ones. It becomes possible to perform clinical analysis.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is a plan view of the apparatus shown in FIG. 1. 2... Holding member, 4... Support block, 10...
...Rotating member, 12... Weighing unit, 18... First cylinder, 28... Rotating cylindrical body, 34, 38
...Magnet, 36...First motor, 40...
...Weighing shaft, 42...Weighing groove, 44...Screw, 46
...Second cylinder, 52...Spur gear, 56...
Second motor, 57...Rotating shaft, 58, 59...
Gear, 62... Spring, 64... Third cylinder,
72... Fourth cylinder, 74... Sleeve, 9
2...Third motor, 90, 94...Gear.

Claims (1)

[Scope of Claims] 1. A support block supported by a holding member, a rotation member pivotally supported by the support block, and a plurality of support members fixed to the rotation member at equal positions from its central axis. A plurality of columnar members are supported and have weighing grooves having different predetermined volumes formed on the circumferential surface near the lower end, and slide between a position where each of the grooves is liquid-tightly sealed and a position where the grooves are opened. It consists of a plurality of sliding members and a drive device configured to rotate the rotary member and stop one of the columnar members at a predetermined position, and the columnar member stopped at the predetermined position. After filling the groove with liquid by immersing it in a liquid in a container to be weighed, sliding the sliding member to a position where the groove is liquid-tightly sealed;
A micro-liquid weighing device characterized in that a predetermined amount of liquid corresponding to the volume of the groove is weighed by separating the columnar member and the container thereafter. 2. The drive mechanism for driving each of the sliding members includes a plurality of cylinders, one of which is screwed onto each of the support members, and a mechanism for transmitting rotational driving force to the cylinders to move the cylinders up and down. 2. A liquid micro-amount measuring device according to claim 1, comprising a rotational driving force transmitting device and a transmitting device that transmits the vertical movement of the cylinder to a sliding member. 3. A support block supported by a holding member, a rotation member pivotally supported by the support block, a plurality of pivot members fixed to the rotation member at equal positions from its central axis, and A plurality of columnar members are each pivotally supported and each of the grooves is formed with a measuring groove having a different predetermined volume on the circumferential surface near the lower end, and a rotary driving force transmitting portion is provided at a position other than the vicinity of the lower end; A plurality of sliding members each slide between a liquid-tight sealing position and an opening position, and one of the columnar members is rotated by rotating the rotating member.
a drive device configured to stop the columnar member at a predetermined position; and a drive force transmission device for transmitting a rotational drive force to the rotational drive force transmission unit to rotate the columnar member stopped at the predetermined position. Consisting of
After the columnar member stopped at the predetermined position is immersed in the liquid in the container to be weighed to fill the groove with the liquid, the sliding member is moved to a position where the groove is liquid-tightly sealed. 1. A micro-liquid weighing device, characterized in that a predetermined amount of liquid corresponding to the volume of the groove is weighed by sliding and then separating the columnar member and the container.