JP2001264341A - Liquid dispension injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the effects of the surface tension of a liquid at an dispensing opening where the surface tension is increased according as the amount of dispensation and becomes very small in case of dispensing a very small amount of a few μL or less. SOLUTION: This liquid dispension injection device for dispensing reagent specimens comprises a nozzle member (54) with a discharging opening diameter d1 to suck and discharge a reagent specimen of surface tension H, syringe piston pump (56) to perform sucking and discharging operation by the reciprocation of a piston, rectilinear reciprocating actuator to reciprocate the piston of the syringe piston pump (56),J a plurality of elastic ring members to seal the liquid by pressing and deformation, and pipe (55a) of a length L and inner diameter d2 through which the reagent specimen flows at a flow velocity V to connect the syringe piston pump (56) to the nozzle member (54). The liquid dispensing device is constituted by the relationship 4H/d1<γ(h-kLV/d22) (wherein, γis the specific gravity of the reagent specimen; and k is a coefficient including the kinetic viscosity coefficient of the reagent specimen).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid dispensing apparatus for dispensing a minute amount of liquid.

[0002]

2. Description of the Related Art As an example of a general dispensing apparatus of the prior art, for example, Japanese Patent Laid-Open Publication No. Hei 6-308134 discloses a reagent dispensing apparatus capable of measuring the inlet of each reagent bottle in a reagent storage. I will.

FIG. 20 shows the above-mentioned Japanese Patent Application Laid-Open No. 6-308134.
FIG. 10 in FIG.
Reference numeral 4 denotes a reagent injection mechanism. This reagent injection mechanism 104 includes a reagent nozzle 105. This reagent nozzle 105
Is connected to a reagent pump 107 via a reagent tube 106. The reagent pump 107 is a pump that can be moved forward and backward and has a cylinder 108. The sliding wall 109 of the cylinder 108 is connected to a lead nut 1 of a lead screw mechanism, which is one of linear motion mechanisms, via a connecting member 110.
11 are connected.

[0004] Next, the lead nut 111 is screwed and inserted into a thread of a lead screw 113 connected to a drive shaft of the stepping motor 112. It reciprocates stepwise along 113. Therefore, the sliding wall 1 of the cylinder 108
Reference numeral 09 reciprocates in a stepwise manner in accordance with the step of moving the lead nut 111, so that a small appropriate amount can be accurately sucked and discharged.

The reagent nozzle 105 and the reagent tube 106 are supported by a reagent arm 114.
The reagent arm 114 can be turned and moved up and down by a rotating mechanism and a lifting mechanism.

On the other hand, as a conventional example of a cylinder pump, for example, Japanese Patent Publication No. 8-27291 discloses an automatic chemical analyzer using a mirror-like ceramic for a sliding surface.

In the cylinder pump shown in FIG. 21, both the cylinder 121 and the plunger 123 are formed of a rigid body, and the cylinder and the plunger 123 are brought into sliding contact with each other without using an elastic body. (About 3 microns or less). As the rigid body, a ceramic itself as a sintered body or a body containing ceramics is used. For example, the cylinder is formed of alumina, which is one of ceramics, and the plunger 123 is formed of zirconia.

[0008] There is no adverse effect on other fluid equipment due to a decrease in discharge accuracy or mixing of abrasion pieces into the flow path, so that the discharge accuracy is excellent and it can contribute to the improvement of measurement accuracy, and the sliding resistance is low. and it is possible to seal the liquid inside, even when used in a multiple-no difference between the discharge amount, moreover abrasion resistance, rich in corrosion resistance and an automatic chemical analyzer with excellent cylinder pump durability It has been disclosed.

[0009]

However, conventionally, several μl
When dispensing a very small amount of liquid, the effect of the liquid surface tension at the discharge port is greater as the dispensed amount becomes smaller.In particular, the discharge pressure for breaking this surface tension is obtained. The phenomenon that cannot be performed occurred. For this reason, even if liquid of about several μl is sent by the syringe piston pump, the sent amount of liquid drops adheres to the discharge port, and the liquid cannot be separated and discharged from the discharge port. This is related to the pressure due to the surface tension of the liquid at the discharge port and the pressure for discharging.

[0010] At this time, the syringe piston pump applies a volume change (pressure) required for liquid feeding to the liquid inside the syringe. However, not all of this pressure becomes the pressure used for liquid discharge at the discharge port. Friction loss (length, diameter, curvature,
The pressure used for liquid ejection at the ejection port has been significantly reduced due to the loss due to steps, throttles, etc.) and the positional relationship between the syringe piston and the ejection port.

Conventionally, the cylinder is arranged separately from the reagent arm, so that the reagent tube is long enough to accommodate the operation of the reagent arm. In such a case, the friction loss in the reagent tube becomes large.

Referring to FIG. 20, the cylinder includes:
It is arranged below the reagent nozzle. In such a case, it is difficult to obtain a sufficient discharge pressure due to the positional relationship between the syringe piston and the discharge port. For this reason, it is necessary for the syringe piston pump to generate an output that exceeds the loss, resulting in an increase in the actuator torque, an increase in the size of the device, and a complete separation of the liquid sent by the syringe piston pump from the discharge port. Dispensing could not be performed, and the dispensing accuracy deteriorated, such as causing some to adhere to the discharge port.

In view of the above, the present invention pays attention to this point, and when performing dispensing in a minute volume region, prevents a drop in the discharge pressure at the discharge port, and does not deteriorate the dispensing accuracy. The aim is to propose a device.

Further, when the sliding surface is formed of a mirror-like ceramic as in the prior art, when an extremely small crack occurs, the seal withstand pressure is greatly reduced or the sliding force of the piston is increased to reduce the motor load. It has been considered that the dispensing accuracy may be changed and the dispensing accuracy may be deteriorated. In addition, it may be easily damaged, and care must be taken when handling. Furthermore, processing of ceramics is generally difficult, and forming a mirror surface without any cracks has the disadvantage of extremely high cost. In addition, the fitting tolerance of the cylinder and the plunger is on the order of μm, and strict accuracy is required for straightness, coaxiality, and the like, which causes an increase in cost. Especially when used in multiple units, the problem of cost cannot be ignored.

Another object of the present invention is to propose a liquid dispensing apparatus which is easy to handle, can greatly reduce the cost, and can cope with a durable surface and the like from the above viewpoints. It is another object of the present invention to provide a small liquid dispensing device that reduces the sliding resistance of the piston and reduces the load on the linear reciprocating actuator.

[0016]

In order to achieve the above object, according to the present invention, in a liquid dispensing apparatus for dispensing a reagent sample, a reagent sample having a surface tension H is installed on a transport member which rotates and moves up and down. a nozzle member having a discharge port diameter d ₁ for suction and discharge, the lower end surface of the syringe piston is arranged with a height difference h upwardly relative to the discharge port, the syringe piston that performs suction and discharge operation by the reciprocating motion of the piston A pump, a linear reciprocating actuator for reciprocating a piston of the syringe piston pump, and a fixed position with respect to the syringe between the piston and the syringe;
An elastic ring member that seals the liquid by pressing deformation, connecting the syringe piston pump and nozzle member, the length L of reagent sample flow at a flow rate V, and a pipe of internal diameter _{d 2, 4H / d 1 <} γ _{(h-kLV / d 2 2} ) is a liquid dispensing apparatus, characterized by being constituted by the relationship (gamma:: specific gravity reagent analyte, k coefficients including kinematic viscosity coefficient of the reagent sample).

Further, the syringe piston pump and the linear reciprocating actuator are mounted on a transport member, and the linear reciprocating actuator is driven by at least one of a rack and pinion system having a backlash removing mechanism, a friction drive system, and a lead system. It is a liquid dispensing device characterized by being configured.

Further, in a liquid dispensing apparatus incorporating a syringe piston pump for dispensing a reagent sample from a discharge port of a nozzle member by reciprocating movement of a piston in a syringe,
The syringe piston pump is installed between the piston and the syringe with a fixed position with respect to the syringe, seals the liquid by pressing deformation, and has a low friction having a cross-sectional shape with a small contact area with the piston. A liquid dispensing device comprising an elastic ring member made of a material.

By using the liquid dispensing apparatus of the present invention having the above-described configuration, when dispensing in a small area, a drop in the discharge pressure at the discharge port can be prevented, and the dispensing accuracy can be maintained. It is possible to provide a small-sized liquid dispensing device which is easy to handle, can greatly reduce the cost, has excellent durability, can reduce the sliding resistance of the piston, and can reduce the load on the linear reciprocating actuator.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, common parts are denoted by common reference numerals.

[First Embodiment] <Structure> FIGS. 1 to 5 and FIGS. 16 and 17 show a first embodiment of the present invention.
An embodiment will be described.

FIG. 1 is a schematic diagram showing a liquid dispensing apparatus and a liquid suction / supply pipe route according to a first embodiment of the present invention. FIG. 2 is a sectional view of the liquid dispensing apparatus. FIG.
It is an upper surface enlarged view of a linear reciprocating actuator. 4 is an enlarged side view of the linear reciprocating actuator, FIG. 5 is a diagram showing a relationship between a discharge port pressure difference and a motor rotation speed, and FIG. 16 is an enlarged cross-sectional view of a seal portion before pressing deformation.
FIG. 17 is an enlarged sectional view of the seal portion after the pressing deformation.

First, in FIG. 1, a nozzle member 54 is supported by a movable transfer member (not shown).
It is moved and arranged above each of the liquid sample container 52 and the reaction container 53. The nozzle member 54 is connected to a syringe piston pump 56 by a Teflon pipe 55a.
Here, the syringe piston pump 56 is disposed on a movable transfer member similar to the nozzle member 54, and shortens the length of the Teflon-made pipe 55a as much as possible. The syringe piston pump 56 includes a separate pipe 55 leading to a liquid supply tank 59, in addition to the connection pipe 55a.
b is connected, and is sequentially connected to the liquid supply tank 59 via the electromagnetic valve 57 and the water supply pump 58. Also,
The syringe piston pump 56 is connected to the nozzle member 5.
The fourth discharge port 54a is disposed above the fourth discharge port 54a.

The above-described syringe piston pump 56 operates when aspirating the liquid sample 52a.
It reciprocates in the direction of the arrow by a linear reciprocating actuator of a stepping motor and a rack and pinion (not shown).

In the liquid supply tank 59, washing water 5
9a or degassed ion-exchanged water is contained therein, and the water supply pump 58 fills and supplies the cleaning water 59a to each of the pipes 55a and 55b, the solenoid valve 57, the syringe piston pump 56, and the nozzle member 54. .

Next, in FIG. 2, the nozzle member 54 is made of metal (made of metal having high corrosion resistance such as stainless steel and titanium).
Alternatively, it is formed of a glass material or a thermoformed Teflon material, and forms a taper at a predetermined angle by drawing or thermoforming toward the discharge port 54a. Is thinner than the other end face of the pipe port 54b.

The nozzle member 54 is connected to a Teflon (registered trademark) pipe 55a through the pipe port 54b, and is connected to a syringe piston pump 56.

The syringe piston pump 56 has a port 60c and is connected to a Teflon pipe 55b. The flow path 60a in the syringe 60 has a taper 60 on the discharge side.
b, the inner diameter of the flow channel 60d is Teflon piping 55a.
It matches the inside diameter.

On the other hand, a plurality of elastic ring members 62, for example, O-rings made of NBR are fixed to the syringe 60 as a seal portion on the side of the linear reciprocating actuator of the port 60 c, and are pressed by the elastic ring presser 63. . Further, the piston 61 is provided with the above-described elastic ring retainer 63.
And the elastic ring member 62, and is disposed as a guide, for example, as an auxiliary support from the OILES bearing 64,
It is connected to a rack 66 of a linear reciprocating actuator.

As this linear reciprocating actuator, a rack and pinion system as shown in FIGS. 3 and 4 is employed. The piston 61 in the figure is connected to a rack 66 and meshes with a pinion 67 formed on a stepping motor drive shaft 65. The rack 66 is connected to a linear slider 70 and is supported in a reciprocating manner.

In the configuration of the rack and pinion, a pin 68 formed on the piston 61 and a pin 70 formed on a base 71a on which the syringe piston pump 56 is disposed.
A tension spring 6 as a backlash removing mechanism during a
9 is attached, and a pressure of the spring 69 is applied to the rack and pinion meshing portion with respect to a direction (a direction in which the piston moves to the left in FIG. 3) discharged from the discharge port 54a.

<Operation> Referring to FIG. 1, the actual suction operation of the liquid to be discharged will be described.

First, the nozzle member 54 is moved above the cleaning tank 51. Next, a predetermined length of the nozzle member 54 is immersed in the cleaning tank 51, the electromagnetic valve 57 is opened, and the cleaning water 59 a in the liquid supply tank 59 is fed into the nozzle member 54 by the water pump 58. Then, the inner peripheral surface, the outer peripheral surface, and the end surface of the nozzle member 54 are cleaned with the cleaning water 59a. At the same time, the piston 61 moves to the middle point while the washing water 59a is being supplied, and the syringe piston pump 56 is filled with the washing water 59a. Thereafter, the solenoid valve 57 is closed, and the nozzle member 54 is
It rises again above 1.

Here, the syringe piston pump 56
The piston 61 moves from the middle point toward the nozzle member 54 by a predetermined amount, and from the discharge port 54a of the nozzle member 54,
The cleaning water 59a is discharged by the moving amount of the piston 61, and the liquid surface meniscus shape of the discharge port 54a is maintained at a constant shape. At this time, the piston 61 converts the rotational motion of the stepping motor drive shaft 65 into a linear motion by the engagement of the pinion 67 and the rack 66, and the piston 61 moves in the syringe 60 according to the rotation angle of the stepping motor, thereby performing the discharging operation. I do. Further, since the rack 66 receives a tensile force in the right direction in FIG. 3 by the tension spring 69, the stop position accuracy at the position where the rack 66 has moved to the discharge completion point is not affected by the backlash, and
Operated with order accuracy.

Thereafter, the piston 61 of the syringe piston pump 56 moves again to the middle point, and a predetermined amount of air is drawn into the nozzle member 54 to form an air layer.

Next, the nozzle member 54 moves above the liquid sample container 52, and
The nozzle member 54 is immersed therein. Thereafter, the piston 61 of the syringe piston pump 56 moves a predetermined amount toward the solenoid valve 57, and sucks a predetermined amount of the liquid sample 52a into the nozzle member 54. Thereby, the washing water 59a and the liquid sample 52a are separated by the above-mentioned air layer.

Subsequently, the nozzle member 54 rises again above the liquid sample container 52 and is moved above the reaction container 53. Thereafter, the piston 61 of the syringe piston pump 56 moves toward the nozzle member 54 by a predetermined amount, and discharges a predetermined liquid sample 52a at a predetermined speed from the discharge port 54a.

Here, a liquid sample 52 of several μl level is prepared.
a, the stepping motor drive shaft 65 is rotated at a high speed so as to generate a discharge pressure that overcomes the surface tension seen in the liquid surface meniscus of the liquid sample 52a at the discharge port 54a. 61
Must be instantaneously moved to a predetermined stop position. In particular, since the amount of movement of the piston 61 is extremely small under a small amount dispensing region, it is difficult to obtain a large discharge pressure required for discharge.

Next, as shown in FIG. 5, when the horizontal axis indicates the motor rotation speed and the vertical axis indicates the discharge pressure at the discharge port, the discharge pressure at the discharge port depends on the motor rotation speed. Is obtained. Since the pressure due to the surface tension is determined by the inner diameter of the discharge port 54a of the nozzle member 54 and is constant, the pressure due to the surface tension as indicated by the dotted line is shown. If the pressure is not raised, the discharge pressure at the discharge port cannot exceed the pressure due to the surface tension.
Even if 1 moves, the liquid sample 52a will only adhere to the discharge port 54a and cannot be separately discharged.

<Effects> According to the first embodiment of the present invention,
By arranging the length of the pipe 55a short, the slope of the pressure characteristic curve at the discharge port can be increased, and
The syringe piston pump 5 is positioned at a higher position than the discharge port 54a.
By arranging 6 upward, the lowermost part of the pressure characteristic curve at the discharge port can be raised.

Hereinafter, this will be described in detail.

As shown in FIGS. 1 and 2, in a state where the liquid is filled up to the discharge port of the nozzle member, if the discharge port diameter is d ₁ and the surface tension of the liquid to be used is H, the surface tension at the end face of the discharge port the pressure _{P 1} by is expressed by _{P 1} = 4H / _d 1. By applying a large discharge pressure P ₂ than the P _1, liquid is discharged from the discharge port.

The discharge pressure P ₂ is greatly reduced by the pressure loss ΔP such as the pipe length L, the pipe diameter d ₂ , and the pipe bending curvature. Among them, the loss due to the pipe length L is reduced by the liquid dispensing apparatus. This has a significant effect on configuration. Further, (height difference in height hin height hout the syringe piston tip of the discharge port) height difference h for the outlet of the source to become a syringe piston pump for generating the discharge pressure (piston tip the syringe) the ejection pressure P ₂ And these can be summarized into the following equation.

[0044] from the theorem of ^{Bernoulli, Pin / γ + Vin 2 /} 2g + hin = Pout / γ + Vout 2/2
g + hout−ΔP = constant (hin−hout) = γ (Vout ² / 2g−Vin ² / 2g) +
γ (hout−hin) −γ △ P Therefore, P ₂ = γ (△ V + h− △ P) γ: liquid specific gravity V: velocity head due to flow velocity difference (: positive value, discharge port flow velocity Vout> flow velocity in syringe Vin) Of the pressure loss ΔP, the friction loss head due to the length of the pipe is ΔP = 32νLV / (gd ₂ ² ) ΔP = kLV / d ₂ ² k: kinematic viscosity coefficient of liquid according to Hagenpoazoille's law (: [nu) coefficients, etc. V: liquid flow rate in the pipe Therefore, if disposed above the height difference h is the discharge port, it is possible to increase the discharge pressure P _2, when arranged below the discharge opening It would be to reduce the discharge pressure P _2.
In addition, if the length of the pipe is reduced and the diameter of the pipe is increased, the pressure loss can be reduced.

That is, at least 4H / d ₁ <γ (h−
By maintaining the relationship of kLV / d ₂ ² ), it is possible to reliably discharge regardless of the speed head due to the flow velocity difference.

Therefore, by disposing the syringe piston pump above the discharge port and making the piping connecting the syringe piston pump and the nozzle member as short as possible, the surface tension at the discharge port can be reduced when dispensing a small amount. A higher discharge pressure can be easily obtained. In addition, by using an inexpensive elastic ring member that is pressed and deformed for the syringe inside the syringe piston pump and the seal mechanism of the piston part, a long service life and reliable sealing pressure resistance can be realized, and the dispensing accuracy when dispensing a small amount is reduced. Thus, a small liquid dispensing apparatus can be realized.

As a result, the discharge pressure at this discharge port is
As shown in FIG. 5, the characteristic changes to a characteristic A as shown in FIG. 5, and the pressure due to the surface tension can be easily exceeded even at a low motor rotation speed. Therefore, a sufficiently large discharge pressure can be generated with respect to the surface tension of the discharge port 54a, and the liquid sample 5 to be discharged is not limited to the kind of liquid to be used and can be discharged even in a small dispensing area.
The discharge flow rate of 2a does not decrease, a small amount of the liquid sample 52a is reliably separated from the discharge port 54a without any remaining liquid, and high dispensing accuracy can be obtained.

Further, when there is a margin in the discharge pressure,
Even if the output of the stepping motor is reduced, sufficient discharge performance can be obtained, and downsizing of the stepping motor and downsizing of the linear reciprocating actuator can be realized. In addition, the syringe piston pump 56 and the linear reciprocating actuator are supported on a conveying member in order to shorten the length of the pipe 55a. However, as described above, the output of the stepping motor can be reduced and the size can be reduced. Therefore, the inertia when rotating the transport member is reduced, and the actuator for operating the transport member can be used with a low output or a small actuator.

Further, the piston 61 is sealed from the outside by an elastic ring member 62 made of an NBR O-ring, which is inexpensive and easy to handle, but the elastic ring member 62 is initially set inside as shown in FIG. , A good seal pressure resistance cannot be obtained, but it is deformed as shown in FIG. 17 by being pressed by the elastic ring presser 63, and the area in contact with the piston 61 is increased, thereby having a good seal pressure resistance. be able to. At this time, if the elastic ring retainer 63 is formed in the syringe 60 so that the amount of pressing force can be changed by, for example, a screw, the amount of tightening can be increased when liquid leakage from the elastic ring member 62 occurs. Thus, a good seal pressure resistance can be restored again. By arranging a plurality of elastic ring members 62 as in the present embodiment and fixing the elastic ring members 62 to the syringe 60 side, variations in the amount of sliding force of the piston 61 can be averaged, and even in long-term use, The amount of sliding force of the piston 61 is hard to change, the output characteristics of the stepping motor can be kept constant, and stable dispensing accuracy can be maintained for a long time.

In addition to the above, the inner diameter of the pipe 55a is increased and the taper is made as gentle as possible (the syringe taper 60).
b, the nozzle member 54 taper, etc.), it goes without saying that the friction loss in the pipe is reduced, and the discharge flow speed is increased, so that the dischargeable area with respect to the motor rotation speed can be widened.

Further, with regard to the remaining air bubbles in the syringe 60, the clearance between the flow path 60a in the syringe 60 and the diameter of the piston 61 is appropriately set, so that the air bubbles in the syringe 60 can be easily removed. It is possible to prevent a decrease in dispensing accuracy.

Further, by disposing the syringe piston pump 56 above the discharge port 54a and shortening the pipe 55a, the discharge pressure is increased, and high liquid dispensing accuracy can be maintained even when dispensing a small amount. Equipment can be provided. Since a margin is provided for the discharge pressure, the output of the actuator can be reduced, and the size of the liquid dispensing apparatus can be reduced.

Further, by disposing a plurality of O-rings of the elastic ring member 62 on the liquid seal of the piston 61,
A liquid dispensing apparatus that can withstand long-term use can be provided with a simple structure and inexpensive parts.

[Second Embodiment] <Structure> FIGS. 6 to 9 show a second embodiment of the present invention.

FIG. 6 is a liquid dispensing apparatus according to a second embodiment of the present invention, FIG. 7 is a perspective view of a linear reciprocating actuator, and FIG. 8 is a side view of the linear reciprocating actuator. FIG. 9 is a view showing a piston shaft shape.

First, as shown in FIG.
Is supported by a movable transfer member (not shown), and is moved and arranged above each of the washing tank 51, the liquid sample container 52, and the reaction container 53. The nozzle member 54 is connected to a syringe piston pump 56 by a Teflon pipe 55a. Here, the syringe piston pump 56 is disposed on a movable transfer member similar to the nozzle member 54, and shortens the length of the Teflon pipe 55a as much as possible. The syringe piston pump 56 is connected to another pipe 55b leading to a liquid supply tank 59 in addition to the connection pipe 55a, and is connected to the liquid supply tank 59 via a solenoid valve 57 and a water supply pump 58 in order. Further, the syringe piston pump 56 is connected to the nozzle member 5.
The fourth discharge port 54a is disposed above the fourth discharge port 54a.

In FIG. 6, the syringe piston pump 56 is held vertically with the flow path 60d side in FIG. 2 as the upper part and the port 60c side as the lower part, and slides in the vertical direction as shown by the arrow. For this reason, the pipe 55a
180 near the syringe piston pump 56
And is connected to the nozzle member 54.

At this time, a friction drive system as shown in FIGS. 7 and 8 is employed as the linear reciprocating actuator. The piston 61 is formed of a metal material that has been heat-treated to increase wear resistance, for example, SUS440C and heat treatment Hv650, and as shown in FIG.
1a, and the piston flat portion 61a is made of a metal stepping motor drive shaft 65 which is similarly wear-resistant.
And is pressurized by the backlash removing mechanism.

This backlash removing mechanism is formed on a roller shaft 74 arranged at a predetermined distance from the stepping motor drive shaft 65 on a base 71b on which the syringe piston pump 56 is installed. One of which makes a point contact with the outer periphery of the piston 61 with the conical taper portion around the roller shaft 74 is a conical roller 75a having a fixed height direction, and the roller shaft 74 is slidable in the axial direction with the piston 61 interposed therebetween. A simple conical roller 75b is provided.
The rollers 75a and 75b are formed of a metal having enhanced wear resistance, and a bearing (not shown) is disposed at the center thereof. The rollers 75a and 75b rotate around the roller shaft 74 as a rotation center without sliding according to the movement of the piston 61. I do. The piston 61 is always pressed against the stepping motor drive shaft 65 with a constant force by a disc spring member 76 pressing the conical roller 75b from above. In addition, the stepping motor drive shaft 65 and the roller shaft 74 are supplementarily connected by the flange 72 to prevent falling.

Here, as the elastic ring member 62a, an O-ring made of a fluorine-based material of a low friction material is used. Further, the nozzle member 54 has the same configuration as that of the first embodiment, and the description is omitted here.

<Operation> In this embodiment, the rotational motion is converted into linear motion only by the frictional force between the orthogonal piston 61 and the stepping motor drive shaft 65 by the friction drive method of the linear reciprocating actuator. Can reciprocate. This piston 61
And the stepping motor drive shaft 65 converts the spring force of the disc spring member 76 by 90 degrees by conical rollers 75a and 75b, and presses the piston 61 against the stepping motor drive shaft 65 with an appropriate amount of force. Yes,
There is no slip in the state of static friction. Therefore, no matter which direction the piston 61 moves in the discharge operation or the suction operation, there is no backlash, and accurate stop position accuracy of the piston 61 can be obtained, and dispensing accuracy can be improved. .

Further, since the elastic ring member 62a is an O-ring made of a fluorine-based material of a low friction material, adhesion of the elastic ring member 62a to the piston 61 and the like are reduced. Can be maintained. The elastic ring member 62a is not limited to the above. Even if the elastic ring member 62a is made of NBR, polyimide, engineering plastic, or ultra-high molecular weight polyethylene, the piston can be made to have low sliding. Can have an effect.

Similarly, the amount of sliding force of the piston 61 can be further reduced, and a low-output stepping motor can be used. In addition, the piston 61 is formed by the flat portion 61a formed on the piston 61 so that the piston 6
The elastic ring member 6 does not rotate around one axis.
2a, the same portion is always the elastic ring member 62a.
And the stability of the sliding force of the piston 61 is maintained.

The syringe piston pump 56
Is held in a vertical direction with the flow path 60d side up and the port 60c side down, so that air bubbles mixed into the syringe 60 can be easily discharged from the discharge port 54a of the nozzle member 54 together with the cleaning water 59a. Can be.

<Effects> In this embodiment, the same effects as in the first embodiment can be obtained. In the present embodiment, the discharge port diameter d ₁ , the pipe inner diameter d ₂ , and the height difference h of the tip of the syringe piston with respect to the discharge port are as shown in FIG. Further, by using the second embodiment of the present invention, the piston 6 can be used both at the time of discharge and at the time of suction.
Backlash does not occur at the 1 stop position, and higher dispensing accuracy can be obtained. Also, by using the elastic ring member 62a having good slidability, the life of the seal portion is improved, and the amount of force required for the piston operation is also reduced, so that the stepping motor and the liquid dispensing device can be downsized. Can be realized.

Third Embodiment <Structure> Next, FIGS. 10 to 15, FIGS. 18 and 19 show a third embodiment of the present invention.

First, FIG. 10 shows a liquid dispensing apparatus according to a third embodiment of the present invention. FIGS. 11 and 13 are side views of a linear reciprocating actuator. FIG. It is a top view. FIG. 14 is a diagram showing a support portion of the guide rail 78, and FIG. 15 is a diagram showing a shape of the lead nut flange 79.

As in the first embodiment of the present invention, the liquid dispensing apparatus is arranged as follows in the liquid suction and supply system.

First, in FIG. 10, the syringe piston pump 56 is directly connected to the nozzle member 54, and is held vertically with the flow path 60d side in FIG. 2 as a lower part and the port 60c side as an upper part. It slides vertically.

Here, as the linear reciprocating actuator, a lead system as shown in FIGS. 11 to 13 is employed. The base 71c has a U-shape as shown in FIG. 14, and has a wall having a step for pressing the guide rail 78 by the leaf spring 81 and a wall for completely restraining and supporting the guide rail 78. ing. A plurality of leads 80 are disposed in parallel with the guide rail 78, and one end of the lead 80 passes through the wall of the base 71c, and the stepping motor drive shaft 6
5 is connected. At the other end of the lead 80, a bearing (not shown) is mounted on the wall of the base 71c and is rotatably supported.

The piston 61 is disposed in parallel with the guide rail 78 and the lead 80, and has an end portion shown in FIG.
Are fixed to a lead nut flange 79 containing a lead nut 83 as shown in FIG. The lead nut flange 79 is formed with a lead nut 83 that meshes with the lead 80, a piston fixing hole 84 that fixes the piston 61, a bearing 82 that can slide smoothly on the guide rail 78, and a pin 68. The lead nut flange 7
The direction in which the piston 61 moves at the time of a discharging operation (downward direction in FIG. 12) is formed by a tension spring 69 having an end fixed to the base 71c.
Is pressurized.

The elastic ring member 62b uses an O-ring made of NBR containing molybdenum disulfide as a low friction material. The nozzle member 54 has a configuration similar to that of the first embodiment, except for a portion directly connected to the syringe piston pump 56.

<Operation> The length of the pipe 55a between the nozzle member 54 and the syringe piston pump 56 is extremely reduced, and the nozzle member 54 is made the same as the pipe 55a.
In-pipe friction loss due to piping can be minimized. Also, a high discharge pressure can be realized at the discharge port 54a,
The liquid feed amount of the piston 61 can be surely separated and discharged under the minute dispensing area. (A sufficient discharge flow velocity can be secured at the discharge port 54a.) The piston 61 of the syringe piston pump 56 is
With the rotation of the stepping motor drive shaft 65, the lead 80
Is rotated, and the lead nut flange 79 is moved by the lead nut 83 meshing with the lead 80, whereby the piston 61 fixed to the lead nut flange 79 reciprocates using the guide rail 78 as a guide. The play between the lead 80 and the lead nut 83 is removed by the tension spring 69 only in the discharge operation direction.

As described above, if the linear reciprocating actuator has the backlash removing mechanism for removing backlash (backlash) in at least the discharging operation direction of the piston 61, the stop position of the piston 61 in the discharging direction is attained. The reproducibility of is improved, and dispensing with good dispensing accuracy can be performed.

The elastic ring member 62b is made of an NBR-based, fluorine-based, polyimide-based, engineering plastic-based material with additives of low sliding promoting material, molybdenum disulfide, tungsten disulfide, silicone, PTFE, etc. If the O-ring is made of ultra-high molecular weight polyethylene and is made of a low friction material, the same operation as in the second embodiment can be obtained, the sliding force can be reduced, the life of the elastic ring member can be prolonged, and the stepping can be performed. The motor output can be reduced. If the cross-sectional shape is a truncated cone as shown in FIG. 18 or an X-shape as shown in FIG.
Thus, when pressed and deformed, a contact area with the piston 61 is secured, and an elastic force is concentrated on a slight elastic ring member contact surface, so that a high sealing pressure resistance is obtained.

<Effects> In the present embodiment, the same effects as in the first embodiment can be obtained. In the present embodiment, the discharge port diameter d ₁ , the pipe inner diameter d ₂ , and the height difference h of the tip of the syringe piston with respect to the discharge port are as shown in FIG. Furthermore, according to the third embodiment of the present invention, the pipe length is minimized, the syringe piston pump 56 and the nozzle member 54 are directly connected, and high dispensing accuracy and significant miniaturization can be realized. It should be noted that a linear reciprocating actuator having a backlash removing mechanism enhances the reproducibility of the stop position of the piston 61, and provides a small liquid dispensing device in which the life of the seal portion is improved by using an elastic ring member 62b made of a low friction material. it can.

[Supplementary Notes] In dispensing liquid dispensing apparatus the reagent analyte, rotation is disposed vertically movable in the conveying member, a nozzle member having a discharge port diameter d ₁ for sucking and discharging the reagent specimen surface tension H, the syringe relative to the discharge port A syringe piston pump in which the piston tip is arranged with a height difference h above and performs a suction / discharge operation by reciprocating motion of the piston, a linear reciprocating actuator for reciprocating the piston of the syringe piston pump, and between the piston and the syringe. An elastic ring member, which is fixed in position with respect to the syringe and seals the liquid by pressing deformation, connects the syringe piston pump and the nozzle member, and the length L and the inner diameter d of the reagent sample flowing at the flow velocity V and a _{second piping, 4H / d 1 <γ (} h-kLV / d 2 2) (γ: specific gravity reagent analyte, k: kinetic viscosity of the reagent analyte Liquid dispensing apparatus characterized in that it is constituted by the coefficient) the relationship includes.

(Corresponding Embodiment of the Invention) Embodiments relating to the present invention correspond to the first to third embodiments.

The nozzle member is a corrosion-resistant metal pipe, glass pipe or Teflon pipe whose area around the discharge port is drawn.

The linear reciprocating actuator is an actuator that converts the rotational motion of the stepping motor into a linear reciprocating motion.

The elastic ring members are an O-ring made of acrylonitrile butadiene rubber (hereinafter abbreviated as NBR) and an O-ring made of a fluorine-based material.

(Operation and Effect) In general, in the state where the liquid is filled up to the discharge port of the nozzle member, if the discharge port diameter is d ₁ and the surface tension of the liquid to be used is H, the pressure due to the surface tension at the end face of the discharge port P ₁ is represented by P ₁ = 4H / d ₁ . By applying a large discharge pressure P ₂ than the P _1, liquid is discharged from the discharge port.

The discharge pressure P ₂ is greatly reduced by a pressure loss ΔP such as a pipe length L, a pipe diameter d ₂ , and a pipe bending curvature. Among them, the loss due to the pipe length L is reduced by the liquid dispensing apparatus. This has a significant effect on configuration. Further, (height difference in height hin height hout the syringe piston tip of the discharge port) height difference h for the outlet of the source to become a syringe piston pump for generating the discharge pressure (piston tip the syringe) the ejection pressure P ₂ And these can be summarized into the following equation.

[0084] from the theorem of ^{Bernoulli, Pin / γ + Vin 2 /} 2g + hin = Pout / γ + Vout 2/2
g + hout−ΔP = constant (hin−hout) = γ (Vout ² / 2g−Vin ² / 2g) +
γ (hout−hin) −γ △ P Therefore, P ₂ = γ (△ V + h− △ P) γ: liquid specific gravity V: velocity head due to flow velocity difference (: positive value, discharge port flow velocity Vout> flow velocity in syringe Vin) Of the pressure loss ΔP, the friction loss head due to the length of the pipe is ΔP = 32νLV / (gd ₂ ² ) ΔP = kLV / d ₂ ² k: kinematic viscosity coefficient of liquid according to Hagenpoazoille's law (: [nu) coefficients, etc. V: liquid flow rate in the pipe Therefore, if disposed above the height difference h is the discharge port, it is possible to increase the discharge pressure P _2, when arranged below the discharge opening It would be to reduce the discharge pressure P _2.
In addition, if the length of the pipe is reduced and the diameter of the pipe is increased, the pressure loss can be reduced.

That is, at least 4H / d ₁ <γ (h−
By maintaining the relationship of kLV / d ₂ ² ), it is possible to reliably discharge regardless of the speed head due to the flow velocity difference.

Therefore, by disposing the syringe piston pump above the discharge port and making the piping connecting the syringe piston pump and the nozzle member as short as possible, the surface tension at the discharge port can be reduced when dispensing a small amount. A higher discharge pressure can be easily obtained. In addition, by using an inexpensive elastic ring member that is pressed and deformed for the syringe inside the syringe piston pump and the seal mechanism of the piston part, a long service life and reliable sealing pressure resistance can be realized, and the dispensing accuracy when dispensing a small amount is reduced. Thus, a small liquid dispensing apparatus can be realized.

2. The syringe piston pump and the linear reciprocating actuator are installed on a conveying member, and the linear reciprocating actuator is configured by at least one of a rack and pinion system having a backlash removing mechanism, a friction drive system, and a lead system. The liquid dispensing device according to claim 1, characterized in that:

(Corresponding Embodiment of the Invention) Embodiments relating to the present invention correspond to the first to third embodiments.

The linear reciprocating actuator includes a stepping motor, and the rotation of the motor is controlled by a rack and pinion method.
This shows an actuator that converts into a linear reciprocating motion by a friction drive system and a lead system.

The backlash removing mechanism includes a tension spring, a disc spring member, and a conical roller.

(Effect, Effect) To operate the syringe piston pump by an inexpensive linear reciprocating actuator by using any one of the rack and pinion system, friction drive system, and lead system to convert the rotary motion into linear motion. Can be. Further, the size can be easily reduced due to the mechanical configuration, and the apparatus can be installed on the transport member. Therefore, the pipe connecting the syringe piston pump and the nozzle member can be shortened, the pulsation phenomenon in the pipe due to the vertical movement of the conveying member does not occur, and high dispensing accuracy can be maintained even when dispensing a small amount.

3. In a liquid dispensing apparatus incorporating a syringe piston pump for dispensing a reagent sample from a discharge port of a nozzle member by reciprocating movement of a piston in a syringe, the syringe piston pump is positioned between the piston and the syringe with respect to the syringe. A liquid dispensing apparatus, comprising: an elastic ring member of a low friction material which is fixedly installed, seals a liquid by press deformation, and has a cross-sectional shape having a small contact area with the piston.

(Corresponding Embodiments of the Invention) Embodiments of the present invention correspond to the second and third embodiments.

The elastic ring member has an O-ring made of a low-friction material having a cross-sectional shape having a small contact area with the piston.

(Operation, Effect) By forming the elastic ring member from a low-friction material and forming the cross-sectional shape into a cross-sectional shape having a small contact area with the piston, the amount of piston operating force can be reduced while maintaining a high sealing pressure resistance. In addition, the durability of the elastic ring member can be improved. Therefore, the piston can operate even with a small-sized and low-output linear reciprocating actuator, and a maintenance-free small liquid dispensing device that can reduce the inertia at the time of installation on the transfer member and at the time of setting the transfer member can be provided.

4. 4. The liquid dispensing device according to claim 3, wherein the cross-sectional shape is a circle, a truncated cone, or an X-shape.

(Corresponding Embodiments of the Invention) Embodiments of the present invention correspond to the second and third embodiments.

The elastic ring member has a circular, truncated conical or X-shaped cross section, and indicates an O-ring made of a low friction material.

(Operation, Effect) The same as the effect of Appendix 3

[0100]

According to the present invention, it is possible to provide a small liquid dispensing apparatus capable of preventing a drop in discharge pressure at a discharge port and maintaining dispensing accuracy when dispensing in a small area. Can be. Further, according to the present invention, it is possible to provide a liquid dispensing apparatus which is easy to handle, can greatly reduce the cost, and has excellent durability. Further, it is possible to provide a small liquid dispensing apparatus capable of reducing the sliding resistance of the piston and reducing the load on the linear reciprocating actuator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a liquid dispensing apparatus and a liquid suction / supply pipe route according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the liquid dispensing apparatus according to the first embodiment of the present invention.

FIG. 3 is an enlarged top view of the linear reciprocating actuator according to the first embodiment of the present invention.

FIG. 4 is an enlarged side view of the linear reciprocating actuator according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a discharge port pressure difference and a motor rotation speed according to the first embodiment of the present invention.

FIG. 6 is a liquid dispensing apparatus according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a linear reciprocating actuator according to a second embodiment of the present invention.

FIG. 8 is a side view of a linear reciprocating actuator according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a piston shaft shape according to a third embodiment of the present invention.

FIG. 10 is a liquid dispensing apparatus according to a third embodiment of the present invention.

FIG. 11 is a side view of a linear reciprocating actuator according to a third embodiment of the present invention.

FIG. 12 is a top view of a linear reciprocating actuator according to a third embodiment of the present invention.

FIG. 13 is a side view of a linear reciprocating actuator according to a third embodiment of the present invention.

FIG. 14 is a view showing a support portion of a guide rail according to a third embodiment of the present invention.

FIG. 15 is a diagram showing a lead nut flange shape according to a third embodiment of the present invention.

FIG. 16 is an enlarged cross-sectional view of a seal portion before pressing deformation according to the first embodiment of the present invention.

FIG. 17 is an enlarged cross-sectional view of the seal portion after pressing deformation according to the first embodiment of the present invention.

FIG. 18 is a view showing a cross section of a flow channel according to a third embodiment of the present invention having a truncated cone shape.

FIG. 19 is a diagram in which the cross-sectional shape of the flow channel according to the third embodiment of the present invention is X-shaped.

FIG. 20 is a diagram showing a configuration of a conventional reagent dispensing apparatus.

FIG. 21 is a view showing a conventional cylinder pump.

[Explanation of symbols]

54: nozzle member, 51: washing tank, 52a: liquid sample, 53: reaction vessel, 56: syringe piston pump,
57: solenoid valve, 58: water pump, 59: liquid supply tank, 60: syringe, 61: piston, 65: stepping motor drive shaft, 69: spring, 108: cylinder

Claims (3)

[Claims] 1. A liquid dispensing apparatus which dispenses a reagent analyte minute, is installed in the conveying member that rotates vertically movable, the nozzle member having a discharge port diameter d ₁ for sucking and discharging the reagent specimen surface tension H, the discharge port A syringe piston pump in which the tip of the syringe inner piston is arranged with a height difference h upward, and performs a suction / discharge operation by reciprocation of the piston; and a linear reciprocating actuator for reciprocating the piston of the syringe piston pump. An elastic ring member which is installed between the piston and the syringe at a fixed position with respect to the syringe and seals the liquid by pressing deformation, and a syringe piston pump and a nozzle member are connected, and the reagent sample flows at a flow velocity V. length L, a and a pipe inner diameter _{d 2, 4H / d 1 <} γ (h-kLV / d 2 2) (γ: reagent analyte specific gravity, k: reagent A liquid dispensing device characterized by a relationship including a kinematic viscosity coefficient of a sample). 2. The syringe piston pump and the linear reciprocating actuator are mounted on a transfer member, and the linear reciprocating actuator is driven by at least one of a rack and pinion system having a backlash removing mechanism, a friction drive system, and a lead system. The liquid dispensing device according to claim 1, wherein the liquid dispensing device is configured. 3. A liquid dispensing apparatus incorporating a syringe piston pump for dispensing a reagent sample from a discharge port of a nozzle member by reciprocating motion of a piston in a syringe, wherein the syringe piston pump is provided between the piston and the syringe. In the above, the elastic ring member of a low-friction material, which is installed in a fixed position with respect to the syringe, seals the liquid by pressing deformation, and has a cross-sectional shape having a small contact area with the piston. Characterized liquid dispensing device.