JP2933117B2 - Plunger pump for analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger pump of an analyzer, and more particularly to a plunger device of an analyzer suitable for use with a quantitative dispenser for a liquid sample or a reagent employed in an automatic analyzer.

[0002]

2. Description of the Related Art In an automatic analyzer, a dispenser for dispensing a liquid sample or a reagent plays an important role. The quantitative dispenser dispenses by sucking or discharging a liquid sample, a reagent, or the like through a nozzle. A plunger pump is used for this dispenser, and a typical example thereof is described in Japanese Patent Publication No. 3-62910. One of the important things in this plunger pump is the sealing property of the plunger performing the reciprocating motion. In order to maintain this sealing property, Japanese Patent Laid-Open Publication No. Hei 3-62910 discloses a method in which a sealing member is connected to a sliding portion on which a plunger slides, and the sealing member is acted on in the axial direction of the plunger. The spring pressing force is converted into a tightening force of the plunger by the sliding portion.

On the other hand, in order to prevent contamination or carry-over, cleaning of the inner wall of the nozzle is frequently performed by flowing cleaning water through the nozzle.

[0004]

In order to improve the processing capacity, it is desirable to increase the amount of washing water and to wash the inner wall of the nozzle in as short a time as possible. The system tends to be under high pressure. However, the technique described above is insufficient in maintaining the sealing property under this high pressure. That is, in order to improve the sealing performance, it is sufficient to increase the pressure of the spring. However, doing so results in an increase in the amount of wear of the seal portion and a reduction in the service life. In addition, the occurrence of abrasion not only causes leakage of liquid from the seal portion, but also that the abrasion debris closes a flow path composed of a fine tube and makes the operation of the apparatus impossible. Causes serious failure.

An object of the present invention is to provide a plunger pump of an analyzer suitable for maintaining higher sealing performance.

It is another object of the present invention to provide a plunger pump for an analyzer which is less likely to cause a failure due to wear debris.

[0007]

The object of the present invention is achieved by the following means.

[0008] and ¥ cylindrical cylinder, a holder provided at an end portion of the cylinder for holding the cylinder, a plunger reciprocating in said cylinder and in said holder, and means for driving the plunger, the holder And a sealing means provided between the plunger and the plunger so as to seal between the plungers, wherein the sealing means has a sliding portion on which the plunger slides. 1, a pressing nut through which the plunger is inserted, and which presses the first sealing to fix it to the holder, and a sliding portion which is housed in the pressing nut and in which the plunger slides. A second sealing having the first sealing and the second sealing disposed between the second sealing and the pressing nut. A spring for pressing the grayed direction,
The first and the second so as to convert the pressing force of the second sealing in the first sealing direction by the spring into the pressing force of the plunger by the sliding portions of the first and second sealings. And a sealing retainer to be combined with the second sealing.

[0009] The A during sealing pressing said plunger, and wherein the first sealing said second
A wear piece receiving portion is provided between the sealing members.

[0010]

[Action] Shi Lumpur means includes a first sealing having a sliding portion where the plunger slides, the pressing nut is fixed to the holder plunger is accounted allowed transmembrane, and to press the first sealing, the holding A second sealing member housed in the nut and having a sliding portion on which the plunger slides; and a second sealing member disposed between the second sealing member and the holding nut to press the second sealing member in the first sealing direction. First and second sealings for converting the pressing force of the spring and the second sealing in the first sealing direction by the spring into the pressing force of the plunger by the sliding portions of the first and second sealings. And a sealing retainer to be combined with the sealing retainer. According to this, since the plunger is sealed at two places by the pressing force of the spring, a stronger sealing effect can be obtained without increasing the tightening force at each place.

A wear piece receiving portion is provided between the sealing retainer and the plunger and between the first sealing and the second sealing. Therefore ,
Since wear debris generated by wear is to accumulate the wear piece receiving portion, reduction of failure due to wear debris is achieved.

[0012]

FIG. 3 shows an embodiment of a quantitative dispenser to which a plunger pump of an analyzer according to the present invention is applied.
The plunger pump 1 includes a cylinder 2, a plunger 3, a sealing 4 of the plunger 3, and a rack and pinion mechanism 6 for converting the rotational motion of the drive motor 5 into a linear motion of the plunger 3. On the other hand, the cylinder 2 is connected to the washing water in the container 9 via an electromagnetic valve 7, a pump 8, and the like,
The other is piped above the nozzle 10 and the washing water is injected to the tip of the nozzle 10. 11 is a moving mechanism of the nozzle 10, 12 is a reagent container, and 13 is a reaction cell.

After the plunger 3 is positioned at the top dead center with the quantitative dispenser configured as described above, the tip of the nozzle 10 is immersed in the reagent in the reagent container 12, and then driven by an amount corresponding to a predetermined dispensing amount. The plunger 3 is moved to the cylinder 2 by rotating the motor 5.
The nozzle 10 is moved in a more withdrawing direction, and a predetermined amount of reagent is sucked into the nozzle 10. After sucking the reagent in this way, the nozzle 10 is moved onto the reaction cell 13 and the plunger 3 is pushed into the cylinder 2 by the rotation of the drive motor 5 by the moved amount, and the reagent sucked into the nozzle 10 is moved. The fixed amount is discharged into the reaction cell 13. The movement amount of the plunger 3 is controlled by using a stepping motor as the drive motor 5 and giving a predetermined amount of pulse input thereto.

When the same dispenser is used for dispensing several kinds of reagents, the nozzle 10 is moved to the washing position (not shown) every time dispensing of one reagent is completed, and the solenoid valve 7 is turned on. Then, the pump 8 is driven to discharge cleaning water from the nozzle 10 to clean the inner wall of the nozzle 10. The quantitativeness of the dispenser in the analyzer configured as described above depends on the plunger and the sheath.
Rings, ie, sealability, are important factors. In a recent analyzer for improving the processing capacity, the pressure of the pump 8 is increased to increase the amount of washing water so that the inside of the nozzle 10 can be washed in as short a time as possible. Therefore, the sealing property must be further ensured.

FIG. 1 shows a main part of a plunger pump of an analyzer according to an embodiment of the present invention. The holder 14 is made of a material having good chemical resistance and relatively high rigidity, for example, ethylene trifluoride resin, and an opening for guiding and housing the plunger 3 and the sealing 4a with a flange, that is, the opening of the plunger 3. Guide hole and sealing 4 with flange
a is formed at the center thereof. The flanged seals 4a and 4b are made of ethylene tetrafluoride resin. The flanges of the seal 4a guided and positioned by the cylindrical hole of the holder 14 and the plunger 3 following the flange are used. It was formed with a sliding part. This sliding portion has a conical end portion and a small-diameter hole which forms a sealing surface with the plunger 3 at the center portion, and a large-diameter hole larger than the small-diameter hole is formed on the flange side interlocked with the small-diameter hole. Formed. The flange surface of the flanged sealing 4 a is screwed into the holder 14, and the end surface of the holding nut 17 having a cylindrical portion guided by the cylindrical hole of the holder 14 is used as the holder 1.
4 is firmly pressed against the bottom surface of the cylindrical hole, and the holder 14 is sealed at the bottom surface of the cylindrical hole. The sealing retainer 20 is housed inside the retainer nut 17 and is fitted to this inner diameter. Both ends of the sealing retainer 20 are fitted with the conical portions of the flanged sealings 4 a and 4 b, and the flanged sealing is applied by the axial force given by the spring 16.
The rings 4a and 4b were pressed down against the plunger 3 and squeezed to form a conical hole for generating a sealing pressure. The outer shape of the sealing retainer 20 was formed smaller than the inner diameter of the retaining nut 17. Further, both ends of the sealing retainer 20 have holes through which the plunger 3 is inserted.
At the center thereof, there is provided a cylindrical hole larger than the insertion hole, and a cake enclosing portion 20a. Since the installation length of the spring 16 is constrained to a fixed size, there is no need to adjust the installation, and maintenance and inspection are easy. Tube 18 and nipple 1
9 is a pipe connection part. In order to obtain a sealing effect with such a structure, the sealings 4a and 4b must have appropriate flexibility, have small and stable frictional resistance against axial movement of the plunger 3, and have a long life. High abrasion resistance in order to obtain the above, and chemical resistance is required when the reagent is directly sucked into the cylinder 2. A tetrafluoroethylene resin has been selected as a material satisfying these conditions. However, in the channel system adopted in the present invention, as described above, the pressure of the pump 8 is increased, for example, by three times and the amount of cleaning water is increased in order to clean the inside of the channel in a short time. Therefore, it is necessary to increase the pressure resistance of the seal, and the spring 16 is strengthened to increase the pressing force of the seals 4a and 4b against the plunger 3, thereby increasing the pressure resistance of the seal. Further, the double seal structure improves the sealing effect.
However, since the spring 16 is strengthened, the sealing 4
The wear pieces a and 4b increase. It is already known that the wear debris is generated on the side where the wall thickness is thinner. Therefore, the debris is generated on the tip side of the inclined portion of both seals and accumulates on the seal 20 side.
The worn pieces are clogged when there is no more escape space, and liquid leakage occurs, so that the worn pieces are accumulated in the worn piece receiving portion 20a of the sealing retainer 20.

The above effect will be described with reference to FIG. The horizontal axis shows the service life and the vertical axis shows the breakdown voltage. The display is a comparison with the conventional product. As is clear from the figure, a large amount of abrasion occurs in the initial stage before the product of the present invention and the product of the present invention are compatible with each other, and the pressure resistance rapidly decreases. It gradually decreases as you get used to it. In the case of a sealing press without a wear piece receiving part, after a certain period,
Causes clogging and drops rapidly. As can be seen from FIG. 2, it is possible to have a lifetime that is three times the withstand voltage and several times the service life of the conventional product.

[0017]

According to the present invention, there is provided a plunger pump of an analyzer suitable for maintaining higher sealing performance.
Is, in addition, plunger pump of hard analyzer cause failure due to wear debris is Ru are provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a plunger pump of an analyzer according to the present invention, which is applied to a quantitative dispenser of the analyzer of FIG.

FIG. 2 is a graph showing a comparison between the pressure resistance of an embodiment of the plunger pump of the analyzer according to the present invention and that of the conventional example.

FIG. 3 is a flow diagram of an embodiment of a quantitative dispenser of the analyzer to which the plunger pump of the analyzer according to the present invention is applied.

[Explanation of symbols]

1-plunger pump, 2--cylinder, 3--plunger, 4a-sealing, 4b-sealing, 5
--- Drive motor, 6-Rack pinion, 7-Solenoid valve, 8-Pump, 9-Container, 10-Nozzle, 11
--- moving mechanism, 12--reagent container, 13--reaction cell,
14-holder, 15-packing, 16-spring, 1
7-holding nut, 18-tube, 19-nipple, 20-sealing holder, 20 a-wear piece receiving part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04B 53/14 F04B 53/02

Claims (1)

(57) [Claims] A cylindrical cylinder, a holder provided at an end of the cylinder for holding the cylinder, a plunger reciprocating in the cylinder and the holder, means for driving the plunger; A plunger pump of an analyzer comprising a holder and a sealing means provided between the holder and the plunger to seal the plunger, wherein the sealing means has a sliding portion on which the plunger slides. A first sealing, a press nut through which the plunger is inserted, and presses the first seal to fix the plunger to the holder; A second sealing having the first sealing and the second sealing disposed between the second sealing and the presser nut. A spring for pressing the grayed direction,
The first and the second so as to convert the pressing force of the second sealing in the first sealing direction by the spring into the pressing force of the plunger by the sliding portions of the first and second sealings. A sealing retainer coupled with the sealing of the second , wherein the sealing retainer and the plan are provided .
Ja, and the first sealing and the second sealing
A plunger pump for an analyzer , wherein a wear piece receiving portion is provided between the sealing members .