JP2500448Y2 - Solvent feeder for analyzer - Google Patents

Description

[Detailed description of the device]

[0001]

TECHNICAL FIELD The present invention relates to a solvent feeding device in an analyzer , and particularly to a liquid chromatograph (liquid chromatography device) using a single-head type reciprocating plunger pump, which favorably causes cavitation during pump suction. The present invention relates to a solvent feeding device that suppresses the above and enables low-pressure gradient analysis.

[0002]

BACKGROUND ART Conventionally, as one of separation / analysis means in the fields of chemistry, biology, medicine, etc., a solvent serving as a mobile phase is transferred from a predetermined storage tank to a liquid chromatograph separation means such as a column by a feeding means such as a pump. Liquid chromatography (LC) in which a sample as an analysis target is introduced into the system while being fed, and the sample is developed and separated by a mobile phase solvent in such a separation means, and the separated sample components are detected. It has been known.

By the way, in a liquid chromatograph as an apparatus for performing such liquid chromatography, in particular, high performance liquid chromatography, conventionally, various kinds of solvent feeders for supplying the mobile phase solvent to the separating means have been constructed. Although proposed, in recent years, one single-head reciprocating plunger pump (feeding means) has been used as the feeding means because of its simple structure, economical advantage, and easy maintenance. In the following, those using a single head pump) have been widely adopted.

However, in the solvent feeding device using only one single head pump as the feeding means,
In order to reduce the pulsation of the solvent to be fed to the separating means, it is necessary to perform the discharge operation gently, while performing the suction operation rapidly (for example, about 1/20 to 1/50 of the discharge time). Therefore, there is a problem that during the suction operation, cavitation is likely to occur on the pump suction side, particularly on the pump chamber, and thus the accuracy of the solvent flow rate is likely to decrease. Of course, if the suction operation of the pump is made slower, it is possible to avoid such a problem, but in this case, the discharge pulsation of the pump becomes large, and the analysis accuracy is significantly reduced due to the pulsation. As a result, there is a problem that analysis becomes impossible, and therefore, there is a limit in slowing the suction operation of the pump and suppressing the occurrence of cavitation.

Further, in recent years, a gradient elution method in which a plurality of kinds of solvents are used as a mobile phase, the mixing ratio of the solvents is temporally changed, and the mixture is fed to a separation means has been widely adopted. In particular, it is possible to perform accurate gradient elution especially when the mixing ratio of solvents is large, and it is economically advantageous because a common pump can be used for the storage tanks that store each solvent. A low-pressure gradient method in which a solvent is mixed on the suction side of a pump has been attracting attention, and it is attempted to perform such a low-pressure gradient analysis using a solvent feeding device that uses only one single head pump. Then, as described above, since it is necessary to perform the suction operation of the pump in an extremely short time (for example, 0.1 to 0.2 seconds), there is a problem that the mixing ratio of the solvent becomes extremely inaccurate. It was. In the low-pressure gradient analysis, the mixing ratio of the solvent is adjusted by controlling the opening / closing of the solenoid valve (valve means) provided corresponding to each storage tank over time. Since the response is as large as 0.01 to 0.02 seconds, it is unavoidable that the operation error of the solenoid valve becomes remarkably large in the short time as described above, and thus the mixing ratio of the solvent becomes remarkably inaccurate. Is unavoidable.

[0006] Therefore, conventionally, it has been difficult to perform low-pressure gradient analysis using such a solvent feeder using only one single-head pump, and the single-head pump is used. When performing gradient elution using a solvent feeder, a high-pressure gradient method in which a solvent is mixed on the discharge side of the pump, which requires an independent pump for each storage tank, has been exclusively used.

Although it is technically possible to perform low-pressure gradient analysis by using a solvent feeding device using one single head pump, in this case, in this case, an electromagnetic wave capable of high-speed response is used. In addition to the need to employ a valve, the control mechanism of the solenoid valve is inevitably complicated, which causes a problem that the manufacturing cost thereof is significantly increased.

On the other hand, in contrast, Japanese Patent Laid-Open No. 55-1221
In Japanese Patent Publication No. 49, two single-head pumps (single-head pump units) are provided in series between a separating means and a storage tank, and these two single-head pumps are synchronously driven. By positively feeding the solvent equivalent to the suction amount from the single-head pump on the storage tank side, the cavitation can be suppressed well and low-pressure gradient analysis can be performed. A solvent feeding method is disclosed, and as a preferable apparatus thereof, two single head pump units are coaxially formed in a common body, and the pump units can be simultaneously driven by a common driving means. What has been done is disclosed.

However, in the solvent feeding device according to the technique disclosed in this publication, as described above, although it is possible to favorably suppress the occurrence of cavitation and enable low-pressure gradient analysis, it is possible to use two devices. Since the pump (pump unit) is required, there is a problem that the structure is complicated and maintenance is troublesome, and the manufacturing cost thereof is significantly high. Since a pump used in such a solvent feeding device is required to have high corrosion resistance against various solvents, for example, the plunger is sapphire and the pump chamber is SUS316 (stainless steel) having excellent corrosion resistance. As described above, each pump component is generally made of a material that is expensive and difficult to process, and therefore, two pumps are used like the solvent feeding device according to the disclosed technique of the above publication. However, the manufacturing cost cannot be avoided.

[0010]

The present invention has been made in view of such circumstances, and its object is to satisfactorily suppress the occurrence of cavitation during pump suction and to perform low-pressure gradient analysis. Enable
An object of the present invention is to provide an inexpensive solvent feeding device having a simple structure using one single-head reciprocating plunger pump.

[0011]

In order to solve the above problems, the present invention is designed so that suction operation is performed more rapidly than discharge operation.
Using the configured single-head type reciprocating plunger pump, while rapidly sucking a predetermined solvent from the storage tank ,
Be sure to gently feed the target part of the analyzer.
In the device, the volume of the reciprocating plunger pump is changed by the deformation or displacement of at least a part of the wall in the suction side flow passage, and the volume change amount is
The discharge amount in one round trip is approximately equal to or slightly higher than
A liquid reservoir part is provided, and a volume changing means for forcibly changing the volume of the liquid reservoir part with the movement of the plunger is interposed between the plunger of the pump and the liquid reservoir part. During the gentle discharge operation of the pump, the volume of the liquid reservoir is forcibly and gradually increased along with the movement of the plunger so that the solvent is guided and retained in the liquid reservoir from the storage tank. On the other hand, during the sudden suction operation of the pump, the volume of the liquid reservoir is forcibly and rapidly reduced with the movement of the plunger, and the solvent retained in the liquid reservoir is pumped. The gist is a solvent feeding device in an analyzing device, which is characterized in that the solvent feeding device is used for feeding.

[0012]

According to the solvent feeding device of the present invention, the solvent from the storage tank is guided and held in the liquid reservoir during the discharge operation of the pump (during the discharge stroke), and the suction operation of the pump is performed. At this time (during the suction stroke), the solvent held in the liquid reservoir is positively sent to the pump (pump chamber). That is, as the volume of the pump chamber increases due to the suction operation of the pump, the solvent is positively replenished in the pump chamber. Therefore, even if the pump is rapidly sucked like the conventional device, the pressure in the pump chamber is significantly prevented from being significantly reduced, and the cavitation is well suppressed from being caused by the sudden pressure reduction. Therefore, it is possible to favorably suppress the occurrence of cavitation without increasing the discharge pulsation of the pump.

Further, in the solvent feeding device according to the present invention, the volume of the liquid reservoir increases as the plunger moves during the discharge operation of the pump, and the solvent stored in the storage tank is guided to the liquid reservoir. Therefore, the time for introducing the solvent to the liquid reservoir is sufficiently long according to the discharge operation time of the pump, and therefore the liquid chromatograph for performing the low pressure gradient analysis in the gradient elution method. In the case of adopting, the solvent can be mixed at an accurate mixing ratio without using a valve means capable of high-speed response. That is, if the solvent feeding device according to the present invention is used in a liquid chromatograph,
By adopting a simple structure in which a valve means having a normal response speed is provided between the liquid reservoir and each storage tank, low-pressure gradient analysis can be performed, and therefore the solvent can be mixed at a large mixing ratio. Of course, this is particularly advantageous in the case of mixing with a difference, and the gradient elution is 1
This is possible only by using a single-head type reciprocating plunger pump and inexpensive valve means can be adopted, which is significantly economically advantageous as compared with the conventional device.

In the present invention, since only one pump (pump unit) is required, there is an advantage that the manufacturing cost of the device is remarkably reduced and there is an advantage that maintenance is easy.

Further, as apparent from the above description, the present invention is particularly applicable to a solvent feeding device for a liquid chromatograph, but is not limited to this. The present invention can also be applied to a solvent feeder similar to the solvent feeder of a liquid chromatograph, such as a solvent feeder of a flow injection analyzer.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described in detail below with reference to the drawings in order to clarify the present invention more specifically.

First, FIG. 1 is a systematic diagram schematically showing an example of a liquid chromatograph for performing low-pressure gradient analysis, which is equipped with a solvent feeding device according to the present invention. Further, there are storage tanks 10 and 12 that are independent of each other, and contain (reserve) different solvents.
The storage tanks 10 and 12 may be closed storage tanks or open storage tanks as illustrated.

Suction branch pipes 14 and 16 are inserted in the storage tanks 10 and 12, respectively, and the suction branch pipes 1 are
A suction main pipe 18 is connected to the valves 4 and 16. In addition, the solvent stored in the storage tanks 10 and 12 is stored in the suction branch pipes 1
It is pumped up through Nos. 4 and 16 and joined at the suction main pipe 18. Further, each suction branch pipe 14,
On the 16 are respectively solenoid valves 2 as valve means.
0, 22 are provided, and the solenoid valve 20, 22 is selectively opened / closed by the controller 24 according to a desired mixing ratio. As a result, the mixed solvent (mobile phase) mixed at a desired mixing ratio is introduced into the suction main pipe 18. In addition, here, the mobile phase is provided as a mixture of two kinds of solvents.
It is also possible to provide it as a mixture of more than one solvent. The mixing ratio of the solvent is, as described above,
In addition to controlling the opening and closing of the solenoid valves individually arranged corresponding to each solvent, the solenoid valves located at the confluence of the suction branch pipes can perform various kinds of switching operations at the same time, such as a three-way valve. It is also possible to adjust by adjusting the solenoid valve by switching control. Moreover, in FIG. 1, 26 and 28 are filtration filters, respectively.

The suction main pipe 18 to which the solvent is introduced from each of the suction branch pipes 14 and 16 has its downstream end portion on the suction side of the single-head type reciprocating plunger pump 30, that is, in the pump chamber 32 of the pump 30. Check valve 3 on the suction side port
4 are connected. Further, the discharge side port of the pump chamber 32 is connected to the solvent supply flow path 38 via a check valve 36. A column 42 as a liquid chromatograph separation means is connected to the solvent supply flow path 38 via a predetermined damper 40, and a predetermined detection means 44 is connected downstream of the column 42. ing.

Here, the pump 30 is provided with a longitudinal body 46 and a pump head 48 fixed to one end portion in the longitudinal direction thereof. The pump chamber 32 is formed inside the pump head 48. A plunger holder 50 is held in the body 46 so as to be movable in the longitudinal direction, and a plunger 52 is coaxially attached to one end of the plunger holder 50. And the pump head 4
The plunger 52 is made to project into the pump chamber 32 formed inside the pump chamber 32, and the pump action is performed based on the reciprocating motion of the plunger 52.

The mobile phase guided in the suction main pipe 18 is sucked into the pump chamber 32 based on the movement (returning) of the plunger 52 to the right in FIG. The mobile phase sucked into the plunger 52 of the plunger 52 shown in FIG.
The solvent feed passage 38 is moved based on the movement (forward movement) in the middle left direction.
It is possible to discharge. Then, the mobile phase discharged to the solvent feeding channel 38 is guided to the column 42 via the damper 40, where the sample is separated and developed, and the sample separated and developed in the mobile phase. Is detected by the detection means 44.

As is apparent from FIG. 1, in this embodiment, the pump operation of the pump 30, that is, the plunger 5 is performed.
The reciprocating movement of 2 causes the pressing force of the compression coil spring 54 that urges the plunger holder 50 in the returning direction (rightward in FIG. 1), and the cam follower 56 fixed to the plunger holder 50. The rotation is performed based on the rotation of 58. Also, in the figure, 6
Reference numeral 0 is a seal member.

By the way, the reciprocating movement of the plunger 52, in order to suppress the discharge pulsation, is based on the shape of the cam 58 and its rotational speed control, and the discharge operation (forward movement) is slow like the conventional device. While the suction operation (return operation) is performed rapidly at a high speed while being performed at a constant speed, in this case, as in the conventional device,
If the volume of the suction main pipe 18 is fixed, the suction operation of the pump 30 is rapidly performed. Therefore, at the time of the suction operation, the volume of the suction side of the pump 30, particularly the inside of the pump chamber 32, increases. Along with this, the pressure is rapidly reduced, and cavitation easily occurs in the pump chamber 32 due to the rapid pressure reduction. In addition, the suction branch pipes 14, 16
Since the time required for sucking the solvent from each of the storage tanks 10 and 12 through is significantly shortened, the mixing ratio of these solvents becomes significantly inaccurate, and the reliability of the analysis result in the detection means 44 is significantly impaired. .

Therefore, in the apparatus of this embodiment, as shown in FIGS. 1 and 2, a rubber elastic tube 62 is interposed on the suction main pipe 18, and the inner volume of the rubber elastic tube 62 is the plunger 52. By reciprocating, the volume of the pump chamber 32 is increased / decreased in the direction opposite to that of the increase / decrease action, thereby eliminating such a problem.

That is, as shown in FIGS. 1 and 2, in this embodiment, the plunger holder 5 is
0 is slidably fitted in a bottomed hole 64 formed in the body 46 at the end opposite to the side supporting the plunger 52. By this fitting, the bottomed hole 6
A closed space 6 located at the bottom of 4 as a fluid storage space
6 is formed. Then, in the closed space 66, as shown in FIG.
A predetermined fluid (e.g., air) that indicates a normal pressure is stored when it is in its returning end position, and the pressure in the sealed space 66 changes according to the moving position of the plunger holder 50. The rubber elastic tube 62 interposed on the suction main pipe 18 is arranged in the body 46 so as to penetrate the sealed space 66.

In other words, during the discharge operation of the pump 30 in which the volume of the pump chamber 32 is reduced, the suction main pipe 1
8 is closed by the check valve 34 at the end on the pump 30 side.
The rubber elastic tube 62 bulges outward based on the depressurizing action of the inside, and the inner volume thereof is increased. As the inner volume increases, each storage tank 1
The solvent (mobile phase) introduced from 0 and 12 into the suction main pipe 18 is mixed and stored in the rubber elastic tube 62. Also, pump room 3
2 is increased, the suction space of the pump 30 is increased, and the sealed space 66 is moved along with the movement of the plunger 52.
The internal volume of the rubber elastic tube 62 is reduced by its elastic force based on the return of the internal pressure to the normal pressure.
As the inner volume of 2 decreases, the mobile phase retained inside is discharged to the outside of the tube. As a result, the pump chamber 3 whose volume increases
The mobile phase is positively sent to 2.

Therefore, according to the apparatus of this embodiment, the rubber elastic tube 62 is used during the suction operation of the pump 30.
The mobile phase discharged from the pump chamber is positively sent to the pump chamber 32, and the mobile phase is positively replenished to the pump chamber 32 as the volume of the pump chamber 32 increases. Even if the suction operation of 30 is suddenly performed, it is possible to favorably prevent the pressure in the pump chamber 32 from being rapidly reduced, and therefore, it is possible to favorably suppress the occurrence of cavitation.

Further, according to the apparatus of this embodiment, since the solvent is sucked through the suction branch pipes 14 and 16 during the discharge operation of the pump 30, the time required for such suction is sufficiently long. Therefore, it is possible to sufficiently reduce the influence of the control error caused by the response of the solenoid valves 20 and 22 and obtain the mobile phase in which the mixing ratio of each solvent is accurate.

The volume change amount of the rubber elastic tube 62 is set to be equal to or slightly larger than the discharge amount by one reciprocation of the pump 30 (plunger 52). Also, here, the rubber elastic tube 6
As the constituent material of No. 2, a material having excellent corrosion resistance to the solvent used, for example, fluororubber (perfluoroelastomer) will be used. Further, in FIGS. 1 and 2, reference numeral 68 denotes a seal member for keeping the closed space 66 airtight.

As described above, according to the apparatus of this embodiment, the single head reciprocating plunger pump 30 is
The low-pressure gradient analysis can be performed only by using the table, and furthermore, cavitation can be favorably prevented from occurring in the pump chamber 32 during the rapid suction operation of the pump 30, so that the flow rate accuracy of the mobile phase is always good. Therefore, it is possible to obtain highly reliable analysis results.

Further, in the apparatus of this embodiment, the above-mentioned Japanese Patent Laid-Open No.
Unlike the solvent feeding device disclosed in Japanese Patent Laid-Open No.-122149, it is sufficient to use one pump unit (pump 30), which is economically extremely advantageous and easy to maintain. There are also advantages.

By the way, in the pump 30, the member with which the solvent (mobile phase) is in direct contact is excellent in corrosion resistance against the solvent used, such as sapphire for the plunger 52 and SUS316 (stainless steel) for the pump head 48. In addition, it is necessary to use an expensive and poorly workable material. Therefore, in the case of using two pump units such as the pump 30 disclosed in the above publication, its structure becomes complicated and its manufacturing cost is low. Is significantly higher and maintenance is troublesome.
On the other hand, in the apparatus of this embodiment, as described above, only one such expensive pump is required, and the other one pump (pump on the storage tank side) is excellent in corrosion resistance to the solvent. Since the rubber elastic tube 62 is replaced by a simple structure, the device can be manufactured at low cost and maintenance can be facilitated.

In addition, in the apparatus of this embodiment, the body 46 of the pump 30 is adopted by using the rubber elastic tube 62.
Since the solvent is prevented from coming into direct contact with the plunger holder 50 and the body 46 and the plunger holder 5,
As the constituent material of No. 0, an inexpensive material such as aluminum having excellent workability can be used, and this also has an advantage that the device can be manufactured at low cost.

Further, in the apparatus of this embodiment, the solenoid valve 2
Since it is not necessary to adopt an expensive one having a high response speed as 0 and 22, this also has an advantage that the device can be manufactured at low cost.

In this embodiment, the closed space 66 forming the fluid storage space of the volume changing means is kept at normal pressure at the backward moving end position of the plunger 52, and the normal pressure is generated by the movement of the plunger 52 in the forward moving end direction. It is made to decompress from
The inner volume of the rubber elastic tube 62 forming the liquid reservoir is increased on the basis of the decrease in the pressure in the closed space 66, while the pressure in the closed space 66 is constantly maintained by the movement of the plunger 52 in the backward movement direction. By returning to the pressure, the inner volume of the rubber elastic tube 62 was reduced based on the elastic force of the rubber elastic tube 62.
The fluid pressure in the closed space 66 is set to be the normal pressure at the forward end position of the plunger 52, and the fluid pressure in the closed space 66 is lower than the normal pressure due to the movement of the plunger 52 in the backward movement end direction. On the other hand, the rubber elastic tube 62 is set to a shape with an increased volume (shape as shown in FIG. 1) in advance, and the rubber elastic tube 62 is kept inside the sealed space 66 during suction operation of the pump 30. It is also possible to positively crush by the fluid pressure of.

Next, another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the configuration of the volume changing means for changing the volume of the liquid reservoir and the liquid reservoir is different from that of the above embodiment, but other configurations are the same as those of the above embodiment. Only the different part will be described in detail.

That is, in the apparatus of this embodiment, FIG.
And the plunger holder 5 as shown in FIG.
0 is slidably fitted in a through hole 70 formed through the body 46, and the opening of the through hole 70 is made of a material excellent in solvent corrosion resistance, such as SU.
By being closed by the closing member 72 made of S316 (stainless steel), a closed space 74 as a fluid storage space is provided.
Are formed. Then, in the closed space 74,
Similar to the above embodiment, a predetermined fluid such as air is enclosed under the same pressure condition as that of the above embodiment.

The closing member 72 is provided with a bellows 76 located on the side of the closed space 74 and having a closed end.
It is welded and fixed at the opening, so that a space with a variable volume is formed in the closed space 74.
Then, similarly to the above-described embodiment, the divided end portion of the suction main pipe 18 penetrates through the closing member 72 and is connected to the space inside the bellows 76 of variable volume.

On the other hand, the closed end (closed wall) of the bellows 76 and the end of the plunger holder 50 are respectively
A connecting rod 78 as a connecting means is connected at both ends in the axial direction thereof, whereby the bellows 76 is mechanically moved in response to the reciprocating movement of the plunger holder 50 as shown in FIGS. 3 and 4. It is designed to be forced to expand and contract. In addition, such bellows 76
The expansion and contraction operations of the sealed space 74 are the same as those in the above embodiment.
It is performed in response to the rise and fall of the fluid pressure inside. The bellows 76 is made of a material such as SUS316 having excellent corrosion resistance against the solvent used.

That is, in this embodiment, the rubber elastic tube 62 in the above-mentioned embodiment is replaced by the bellows 76, so that the internal volume of the bellows 76 changes due to the reciprocating movement of the plunger 52. Based on this, the same effect as that of the above-described embodiment can be obtained. It is needless to say that the apparatus of this embodiment also makes the manufacturing cost remarkably lower and makes the maintenance easier than the apparatus disclosed in Japanese Patent Laid-Open No. 55-122149. is there.

Further, as apparent from the above description, in this embodiment, the bellows 76 constitutes the liquid reservoir, but here, as described above, the closing wall of the bellows 76 is connected. Since it is mechanically connected to the plunger holder 50 by the rod 78, there is an advantage that the volume change amount of the bellows 76 can be accurately set in accordance with the movement amount (stoke) of the plunger 52, and therefore, There is an advantage that the amount of the mobile phase discharged from the bellows 76 can be accurately set according to the suction amount of the pump 30 during the suction operation of the pump 30.

In this embodiment, the closing wall of the bellows 76 is displaced (deformed) by the pressure of the fluid contained in the connecting rod 78 and the closed space 74, whereby the bellows 76 as the liquid reservoir is displaced. Although the volume is changed, the bellows 76 can change the volume by only one of them. For example, in FIGS. 3 and 4, the enclosed space 7
4 may be opened to the external space through a predetermined through hole, or the connecting rod 78 may be omitted.

FIG. 5 shows still another embodiment of the present invention. It should be noted that this embodiment is characterized in that the structure of the liquid reservoir is different from the previous embodiments. Further, FIG. 5 shows a diagram corresponding to the operating mode in which the plunger 52 is at the forward movement end position.

That is, in this embodiment, as shown in FIG. 5, the opening end side portion of the through hole 70 in the above embodiment is formed as a large diameter portion 80 over a predetermined length, and the plunger holder 50 is provided. The end of this is the large diameter part 80
The large-diameter portion 82 is slidably fitted to the. The large diameter portion 80 of the through hole 70 has its opening closed by a closing member 84 made of the same material as the closing member 72 in the above-described embodiment, whereby the closing member 84.
A closed space 86 as a fluid storage space is formed between the large diameter portion 82 of the plunger holder 50 and the. And
In the sealed space 86, a predetermined fluid such as air is sealed under the same pressure condition as that of the above embodiment. The large diameter portion 82 of the plunger holder 50 and the stepped portion 8 of the through hole 70
The space between 8 and 8 is opened to the external space through the through hole 90.

Further, in the hermetically sealed space 86, the peripheral portion is airtightly sandwiched by the closing member 84 and the body 46, and a material having a good corrosion resistance to a solvent, for example, SUS316.
A diaphragm 92 made of a metal material such as the above or an elastic material such as fluororubber is provided. Then, the divided end portion of the suction main pipe 18 is connected to the space surrounded by the diaphragm 92 and the closing member 84 so as to penetrate the closing member 84.

That is, in this embodiment, the diaphragm 92
, Which constitutes the liquid reservoir, the apparatus having such a constitution can also obtain the same effect as that of the above-mentioned embodiment, and such an effect can be achieved by the inexpensive constitution.

When the diaphragm 92 is made of a metal material, a diaphragm having a wavy cross section in the radial direction is usually used. Also, the diaphragm 92
When is made of a metal material, it is desirable to connect the plunger holder 50 and the diaphragm 92 by a mechanical connecting means, as in the embodiment shown in FIG.

Although some embodiments of the present invention have been described above, they are literal examples, and the present invention should not be construed as being limited to these specific examples.
Of course.

For example, in each of the above embodiments, the case where the present invention is applied to the solvent feeding device of the liquid chromatograph for performing the low pressure gradient analysis has been described.
INDUSTRIAL APPLICABILITY The present invention can be applied to a solvent feeding device of a liquid chromatograph which does not perform such gradient elution and uses only one type of solvent as a mobile phase, and further, a solvent feeding device of a flow injection analyzer. It is also possible to apply to a solvent feeding device of an analyzer other than the liquid chromatograph. Even when one type of solvent is used as the mobile phase, the volume change amount of the liquid reservoir is usually
It is desirable to set the discharge amount equal to or slightly larger than the discharge amount by one reciprocation of the pump (30).

In each of the above embodiments, the liquid reservoir is directly connected to the solenoid valves 20 and 22 through the suction main pipe 18, and a part of the mobile phase discharged from the liquid reservoir is part of the solenoid valve 20. , 22 can be backflowed, but as shown in FIG. 6, a check valve 94 for backflow prevention is provided in the suction main pipe 18 upstream of the liquid reservoir (here, the rubber elastic tube 62). Therefore, it is also possible to surely send the mobile phase discharged from the liquid reservoir to the pump chamber 32 side. In addition, such a check valve
It can be provided even in the case where one type of solvent is used as the mobile phase. In addition, as a constituent material of the liquid reservoir, a material having excellent corrosion resistance against the solvent used is naturally used.

Further, in each of the above-described embodiments, the reciprocating movement of the plunger 52 is performed based on the urging force of the compression coil spring 54 and the rotation of the cam 58. Can be performed by using an appropriate mechanism such as one using air pressure or one using a feed screw mechanism.

Although other specific examples are omitted, it goes without saying that the present invention can be implemented in various modified, modified, and improved modes without departing from the spirit of the invention. is there.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a main part showing a different operation form of the embodiment shown in FIG.

FIG. 3 is an explanatory view of a main part showing a state where a bellows is expanded in another embodiment of the present invention.

FIG. 4 is an explanatory view of a main part showing a state where the bellows is contracted in the embodiment shown in FIG.

FIG. 5 is an explanatory view of a main part showing still another embodiment of the present invention.

FIG. 6 is an explanatory view of a main part showing still another embodiment of the present invention.

[Explanation of symbols]

 10, 12 Storage tank 14, 16 Suction branch pipe 18 Suction main pipe 20, 22 Solenoid valve (valve means) 30 Single head type reciprocating plunger pump 32 Pump chamber 42 Column 44 Detecting means 46 Body 48 Pump head 50 Plunger holder 52 Plunger 62 Rubber elastic tube (reservoir part) 66,74,86 Sealed space (fluid storage space) 72,84: Closing member 76 Bellows (reservoir part) 78 Connecting rod (connecting means) 92 Diaphragm (reservoir part) 94 Check valve

Claims (7)

(57) [Scope of utility model registration request] 1. A suction operation is performed more rapidly than a discharge operation.
A single-head type reciprocating plunger pump configured as described above is used to rapidly aspirate a predetermined solvent from the storage tank.
To one, at the device so as to gradually feed the site of interest of the analyzer, the volume in the flow path of the suction side of the reciprocating plunger pump, by at least a portion of the deformation or displacement of the wall portion As the volume changes, the amount of change in volume
A liquid reservoir portion that is approximately equal to or slightly larger than the amount is provided, and the volume of the liquid reservoir portion is forced between the plunger of the pump and the liquid reservoir portion as the plunger moves. Interposing a volume changing means for changing to
During the gentle discharge operation of the pump, the volume of the liquid reservoir is forcibly and gently changed as the plunger moves.
While the solvent is guided from the storage tank to be held in the liquid reservoir, the volume of the liquid reservoir is forcibly changed with the movement of the plunger during the sudden suction operation of the pump. The solvent feeding device in the analyzer , wherein the solvent retained in the liquid reservoir is rapidly fed to the pump. 2. The solvent according to claim 1, further comprising a check valve located between the liquid reservoir and the storage tank for preventing a backflow of the solvent from the liquid reservoir to the storage tank. Feeding device. 3. A valve means which comprises a plurality of storage tanks for respectively storing different solvents, wherein the plurality of storage tanks are connected to the liquid storage section and prevent and allow the flow of each solvent. The solvent feeding device according to claim 1 or 2, wherein is disposed between the liquid reservoir and each storage tank. 4. The volume changing means is configured by causing an end portion of a plunger holder supporting the plunger to project into a predetermined fluid storage space formed in a body of the pump, and The liquid reservoir is provided so as to define a part of the fluid containing space, and the volume of the liquid reservoir is raised or lowered by the fluid pressure in the fluid containing space based on the operation of moving the end of the plunger holder. The solvent feeding device according to any one of claims 1 to 3 , wherein the solvent feeding device is adapted to be increased or decreased substantially in inverse proportion to. 5. The solvent feeding device according to claim 4 , wherein the liquid reservoir is made of a rubber elastic tube or bellows or a diaphragm having excellent corrosion resistance against the solvent. 6. The volume changing means is a connecting means for mechanically connecting a wall portion of the liquid reservoir, which is deformable or displaceable, and a plunger holder supporting the plunger, and The volume of the liquid reservoir can be increased or decreased by mechanically deforming or displacing the deformable or displaceable wall portion with the movement of the plunger holder. 3. The solvent feeding device according to any one of 3 above. 7. The liquid reservoir is a metal bellows or diaphragm excellent in corrosion resistance to the solvent, and the connecting means connects the bellows or diaphragm and the plunger holder respectively in an axial direction. The solvent feeding device according to claim 6, which is a connecting rod connected at both ends.