JPH10206405A - Liquid-transferring pump for liquid chromatograph and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent salt contained in an eluent from being deposited to a plunger surface and to suppress the deterioration of a plunger seal with a simple configuration by forming a plunger with porous sapphire. SOLUTION: A plunger 22 is subjected to sliding motion in a pump room 12 by an urging force by a spring 26 and the rotation of a cam 24 by a motor, thus feeding an eluate to a column through a suction passage 27, a pump room 12, and a discharge passage 28. Sapphire is used for the plunger 22 and the surface is set to a porous surface 22a. The surface of sapphire becomes porous due to light beam machining by ArF excimer laser. As a result, water can be easily retained in a fine hole on the surface of the plunger 22, so tat water can be further retained when the surface of the plunger 22 becomes dry and hence suppressing the adhesion of salt to the surface of the plunger 22, thus suppressing the deposition of salt that is generated with the adhering salt as nuclei.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chromatograph feed pump for sending an eluent by reciprocating a plunger and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in the high performance liquid chromatograph, a reversed phase chromatograph using a weakly polar liquid or a nonpolar liquid as a stationary phase and using a strongly polar solvent as a mobile phase has become mainstream. In this reversed-phase chromatography, water, an organic solvent (eg, methanol, acetonitrile, etc.), and a buffer are used alone or as a mixture as eluents. In an ion exchange chromatograph or an aqueous gel permeation chromatograph, an aqueous solution of salts is used as an eluent. It is well known that when a solvent containing such salts is used as an eluent, deterioration of a pump seal of a liquid sending pump is remarkably quicker than when an organic solvent is used as an eluent. This is due to the precipitation of salt on the plunger surface.

In order to prevent this precipitation, a chamber is formed between two seals using two plunger seals, as shown in, for example, Japanese Utility Model Application Laid-Open No. 58-169561, and an inlet and an outlet are provided for this chamber. 2. Description of the Related Art There has been proposed a liquid feed pump for flowing water into a room to prevent precipitation of salt.

[0004]

The above-mentioned pump in which a chamber is formed between two seals using two plunger seals is effective in suppressing salt precipitation. But,
Such a liquid sending pump has a complicated configuration. In addition, when water is supplied only when necessary, the operator has to perform a complicated operation of periodically checking the plunger and supplying water when necessary. Furthermore, if the water is forgotten, the salt will precipitate and the pump seal will deteriorate. In addition, the plunger penetrates as many as two plunger seals, increasing the sliding resistance of the plunger.
Higher power motors must be used. For this reason, power consumption also increases.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to improve the structure of the plunger itself so that salt is less likely to precipitate, and to suppress the deterioration of the pop plunger seal even with a simple structure. An object of the present invention is to provide a liquid sending pump for chromatography.

[0006]

According to the present invention, a single crystal sapphire is used for the plunger in a liquid chromatograph liquid sending pump for sending an eluent by reciprocating a plunger, and the plunger is made porous. It is characterized by:

[0007] Due to this porous structure, in the liquid pump for liquid chromatography, moisture is easily retained in the fine holes in the surface of the plunger, so that even when the plunger surface is in a dry state, more moisture is absorbed. Since the salt can be retained, the adhesion of the salt to the plunger surface can be suppressed, and as a result, the precipitation of the salt generated by using the attached salt as a nucleus can be suppressed. Moreover, since a sapphire single crystal is used as a material, a plunger excellent in mechanical strength, chemical resistance, and the like can be obtained.

In the present invention, the surface is made porous by irradiating a light beam such as an excimer laser to a plunger made of sapphire, which is a single crystal material which has been conventionally difficult to process. A porous plunger is manufactured by obtaining a fine porous surface without deterioration in strength. Then, a liquid feed pump is manufactured using the plunger.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of a high-performance liquid chromatograph liquid sending pump according to an embodiment of the present invention.
This pump comprises a cylinder 11, a pump head 13 having a pump chamber 12, and a flange 14 for fixing the pump head 13 and the cylinder 11. Cylinder 11
A plunger holder 21 is attached to one end of the crosshead 20 fitted inside the plunger holder 2.
1, a plunger 22 is fixed so as to be press-fitted. A cam follower 23 is provided on the other end side of the crosshead 20, and the cam follower 23 is in contact with a peripheral edge of a cam 24 rotated by a motor.

The plunger 22 is inserted into the pump chamber 12, and has a plunger seal 2 at a connection portion with the flange 14.
5 is inserted. And the plunger 22 is the spring 2
The sliding motion in the pump chamber is performed by the biasing force of the motor 6 and the rotational motion of the cam by the motor.

The pump chamber 12 is formed with a liquid suction passage 27 and a liquid discharge passage 28 each having a check valve, and the pumping action of the liquid is performed by the sliding movement of the plunger. Thereby, the eluent is sent from the mobile phase storage tank to the external column through the liquid suction path 27, the pump chamber 12, and the liquid discharge path 28.

The above structure is the same as that of the conventional plunger pump. In the liquid feed pump according to the present invention, sapphire is used for the plunger 22 used in the above-described pump, and the surface thereof is artificially made to be a porous surface 22a. The single crystal sapphire plunger 22 itself has been used conventionally because it has high hardness, high mechanical strength, and excellent chemical resistance. However, on the other hand, a salt is easily deposited on the surface, so that it is necessary to provide a mechanism for performing water washing as shown in the conventional example. In the present invention, the sapphire surface is made porous by the method described below.
Since it can be set to 2a, it is possible to increase the water holding power of the sapphire surface, thereby suppressing the precipitation of salt. That is, moisture is easily retained in the fine holes provided on the plunger surface, and therefore, even when the surface of the plunger 22 is in a dry state, moisture can be retained in the porous surface 22a of the plunger. Therefore, it is possible to suppress the attachment of the salt, and as a result, it is possible to suppress the precipitation of the salt having the attached salt as a nucleus.

Next, a method for making the surface of sapphire porous will be described. FIG. 2 is an explanatory view of a method used for making the sapphire surface porous. As shown in the figure, sapphire is made porous by light beam processing that is irradiated in a pulsed manner. In the figure, 31 is an ArF excimer laser, 32 is a mask, 33 is a driving device for scanning the mask, 34 is a work driving device for rotating the sapphire S back and forth, 35 is an ArF excimer laser 31, a mask driving device 33, and a work. This is a control device that controls the driving device 34.

As shown in the figure, a laser beam irradiated from an ArF excimer laser 31 is directed to a mask 32 via a condensing optical system for converging the laser beam, and the laser beam passing through the mask is further condensed to work. Sapphire plunger. Then, the sapphire surface is finely removed by the laser light energy, and the sapphire can be made porous. Laser irradiation conditions are, for example, an energy density of 2 to 4 J / cm 2 and a sapphire surface with a depth of 1 to 0.2 μm per pulse is removed. Thus, microporous processing without microcracks on the sapphire surface can be performed.

In particular, Ar which is ultraviolet light having a wavelength of 193 nm is used.
Unlike infrared light such as CO2 lasers and YAG lasers, F excimer lasers absorb most of their energy only in the micron-level surface area, and can break chemical bonds by photolysis without heat. it can. Therefore, since it does not cause damage or thermal effect except for the irradiated part of the material, a very high quality porous sapphire plunger can be obtained, which is the optimal processing for processing sapphire plungers used in severe conditions Is the law. Although the hole becomes deeper than that of the ArF excimer laser, it is possible to form a hole even by light beam processing using a CO2 laser.

Further, the diameter of the porous hole can be adjusted by changing the energy of the laser.
Those of about 3 microns are suitable for plunger pumps. The surface area of the porous material can be adjusted by adjusting the irradiation area of the laser, but the surface area of the porous material is preferably set to 0.1 to 5% (particularly 0.1 to 1%) of the entire area. The effect of suppressing salt precipitation was excellent.

In the present invention, the material of the plunger is single crystal sapphire. However, the same effect can be obtained with various other single crystal materials such as ruby and YAG as long as the requirements for the plunger can be satisfied. can get.

It is conceivable to use a sintered ceramic material instead of a single crystal material such as sapphire or ruby as a porous plunger material. However, the sintered ceramic material has an improved hardness and surface roughness. Therefore, a porous sapphire plunger is a more effective material because it is inferior to sapphire or the like in terms of workability for forming.

[0019]

According to the present invention, the plunger which reciprocates through the pump seal is formed of porous sapphire, and water enters and stays in the pores on the plunger surface. Therefore, there is an excellent effect that the precipitation of the salt contained in the eluent on the plunger surface is prevented, and the deterioration of the pump seal can be greatly suppressed.

In addition, there is an excellent effect that the structure is simple, the production cost and the running cost can be reduced, and there is no need to perform a special operation for preventing the precipitation of salt at the time of use.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid chromatography pump according to an embodiment of the present invention.

FIG. 2 is a view for explaining a method for making a plunger porous for use in a liquid chromatograph liquid transfer pump according to one embodiment of the present invention.

[Explanation of symbols]

 11: Cylinder 12: Pump chamber 13: Pump head 14: Flange 22: Plunger, 22a: Porous surface 25: Plunger seal 31: ArF excimer laser 32: Mask 33: Mask driving device 34: Work driving device 35: Control device

Claims (2)

[Claims] 1. A liquid chromatography pump for liquid chromatography which reciprocates a plunger to feed an eluent, wherein the plunger is formed of porous sapphire. 2. A liquid chromatograph liquid transfer pump according to claim 1, wherein said sapphire plunger of said liquid chromatograph liquid transfer pump is manufactured by making its surface porous using a light beam of an excimer laser. Production method.