JP4972613B2 - Liquid feeding device and liquid chromatograph - Google Patents

Description

  The present invention relates to an apparatus for feeding a liquid, and more particularly to a liquid feeding apparatus for feeding an eluent and a liquid chromatograph including the liquid feeding apparatus in an analyzer such as a liquid chromatograph.

  In the liquid chromatograph, an eluent is sent to a separation column by a liquid feeding device. A sample is introduced into a separation column by a sample introduction device, components constituting the sample are separated from each other while the sample passes through the separation column, and the separated sample components are detected by a detector. The detected signal of the sample component is transmitted to the data processing device, and necessary processing is performed.

  The liquid feeding device applies a predetermined pressure to the eluent according to the analysis result, discharges the eluent, and sends the liquid. When the discharge pressure of the eluent is constant, the flow rate is also constant. Therefore, it is ideal that the liquid feeding device always feeds liquid at a constant flow rate. If the flow rate is not constant, the analysis accuracy decreases. In general, in a liquid feeding device, a phenomenon that the flow rate fluctuates periodically (this phenomenon is hereinafter referred to as a pulsating flow) occurs.

  The main method for reducing the pulsating flow is to use a damper. This damper reduces pressure changes and flow rate changes that may occur when the liquid delivery device flows out. As such an example, Patent Document 1 is cited.

JP 2005-164510 A (published on June 23, 2005)

  If a damper is added to the flow path, there are problems such as an increase in the liquid feeding time due to the occurrence of a dead volume and a cause of liquid accumulation, and stable liquid feeding at a constant flow rate from the liquid feeding device is not possible. There was a problem.

  This will be described in more detail below. The damper is configured by providing a plurality of elastic tubes in a pressure-resistant cylinder. The elastic tube is deformed by the pressure of the mobile phase passing through the cylinder, and the volume in the cylinder changes due to this deformation. Specifically, when the pressure of the mobile phase is large, the volume in the cylinder becomes large, while when the pressure of the mobile phase is small, the volume in the cylinder becomes small. Thereby, rapid pressure fluctuation in the cylinder is prevented, and as a result, pulsating flow can be prevented.

  However, if this damper is added, the flow path including the damper itself becomes a dead volume, which causes problems such as an increase in liquid feeding time and a cause of liquid accumulation.

  The present invention relates to a liquid chromatograph liquid feeding device capable of reducing a pulsating flow without changing a flow path and providing a dead volume, and capable of stable liquid feeding at a constant flow rate, and a liquid equipped with the liquid feeding device An object is to provide a chromatograph.

  In order to achieve the above object, the liquid feeding device of the present invention includes a piston that reciprocates and a valve that prevents backflow, and includes an elastic member that exerts an elastic force on the piston.

  Moreover, the liquid chromatograph of the present invention includes the above-described liquid feeding device.

  According to the present invention, the pulsating flow of the liquid feeding device can be reduced by the action of the elastic member without causing problems such as a dead volume and a cause of liquid accumulation.

  The above and other embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 3 shows an example of a liquid chromatograph including a high-pressure gradient liquid delivery apparatus configured using two liquid delivery apparatuses of the present embodiment and a high-pressure gradient liquid delivery apparatus. In addition, the method of using two liquid feeding apparatuses, mixing a liquid under high pressure, and sending liquid while changing the ratio with time is called a high pressure gradient.

  In this liquid chromatograph, the eluents 27 and 28, the liquid feeding devices 25 and 26, the T-shaped connecting tube 29, the mixer 30, the sample introduction device 31, the column oven 33, the detector 34, and the data processing device are sequentially arranged from the upstream side. 35. A separation column 32 is arranged in the column oven 33.

  The liquid feeding devices 25 and 26 send the eluents 27 and 28 to the separation column 32 via the T-shaped connection pipe 29 and the mixer 30. The sample introduction device 31 introduces a sample into the separation column 32. While passing through the separation column 32, the components constituting the sample are separated from each other. The detector 34 detects the sample component separated by the separation column 32. The signal of the detected sample component is transmitted to the data processing device 35, and the data processing device 35 performs necessary processing on this signal.

  The operation of the liquid chromatograph shown in FIG. 3 will be described in more detail.

  The liquid feeding devices 25 and 26 send liquids while changing the flow rates of the separation liquids 27 and 28 with time, and the eluents 27 and 28 merge at the T-shaped connecting pipe 29. The combined eluents 27 and 28 are stirred together by the mixer 30, and then the sample to be analyzed is added to the eluents 27 and 28 by the injector in the sample introduction device 31.

  The eluents 27 and 28 to which the sample is added by the sample introduction device 31 are introduced into the separation column 32. In order to perform multi-component separation with good reproducibility, the separation column 32 is installed in a column oven 33 maintained at a constant temperature. Each component separated by the separation column 32 is detected by the detector 34, and the data is processed and stored by the data processor 35. In this embodiment, the data processing device 35 also controls the operation of each unit (liquid feeding device 25, liquid feeding device 26, sample introduction device 31, column oven 33, detector 34).

  FIG. 1 is a schematic configuration diagram of a liquid feeding device.

  As shown in FIG. 1, the liquid feeding device includes a first pump chamber 1 and a second pump chamber 2 in order from the upstream side, and the first piston 3 and the second piston 4 are respectively provided in the pump chambers 1 and 2. Is arranged. Each of the first pump chamber 1 and the second pump chamber 2 is provided with a first seal 7 and a second seal 8 in order to prevent leakage of liquid to the first piston 3 and the second piston 4 side. The first pump chamber 1 has an inlet port 15 and an outlet port 16, and the second pump chamber 2 has an inlet port 17 and an outlet port 18.

  The first piston 3 and the second piston 4 reciprocate as the cam 10 rotates. The cam 10 has a motor 11 disposed at one end of the shaft, and rotates by driving the motor 11. The inlet side valve 5 and the outlet side valve 6 for backflow prevention are opened and closed in accordance with the reciprocating motion based on the rotation of the first piston 3 and the second piston 4. By the operation of the first piston 3, the second piston 4, the inlet side valve 5, and the outlet side valve 6, the eluent 9 passes from the first pump chamber 1 into the second pump chamber 2 and flows into the second pump chamber 2. Liquid is sent to the outlet side.

  A detection plate 12 and a position detection sensor 13 are provided at the other end of the shaft of the cam 10, and the angular position of the shaft of the cam 10 detected by the position detection sensor 13 is introduced into the control device 14. Further, a pressure sensor 19 is provided downstream of the second pump chamber, and the pressure sensor 19 measures and introduces pressure into the control device 14.

  In the embodiment of the present invention, passive check valves are used as the inlet-side valve 5 and the outlet-side valve 6 for preventing backflow. However, it is also possible to use an active solenoid valve or a rotary adjusting valve. is there.

  When the eluent is sent from the inlet side to the outlet side of the first piston 3 and the second piston 4, the flow rate of the eluent sent is periodically changed due to the influence of the first piston 3 and the second piston 4. A fluctuation phenomenon (pulsating flow) occurs.

  In order to alleviate this problem, in the present embodiment, disc springs 20 and 21 are used instead of the damper disclosed in the prior art.

  More specifically, a disc spring 20 is disposed between the first piston 3 and the cam 10, and a disc spring (elastic member) 21 is disposed between the second piston 4 and the cam 10.

  Here, the disc spring has a property of contracting when the pressure from the outside increases, and extending when the pressure from the outside decreases. Therefore, (a) when the pressure from the outside against the disc spring increases, that is, when the pressure inside the pump chamber increases, this pressure decreases due to the action of the disc spring, and conversely (b) against the disc spring. When the pressure from the outside decreases, that is, the pressure inside the pump chamber decreases, this pressure increases due to the action of the disc spring.

  Therefore, the pulsating flow can be reduced without generating a dead volume as in the case where the damper is provided.

  In this embodiment, the disc springs 20 and 21 are installed between the first piston 3 and the second piston 4 and the cam 10. If so, it can be installed at different positions. Further, as long as an elastic force is exerted on the first piston 3 and the second piston 4, it does not necessarily have to be on the straight line of the reciprocating motion of the first piston 3 and the second piston 4.

  Moreover, in this embodiment, although the disc spring is used as an elastic member, it is also possible to use a resin material.

  Moreover, in this embodiment, although the 1st piston 3 and the 2nd piston 4 are controlled using a twin cam, as shown in FIG. 2, the liquid feeding which controls the 1st piston 3 and the 2nd piston 4 independently. A device is also possible.

  In FIG. 2, the liquid feeding device includes a first pump chamber 1 and a second pump chamber 2, and a first piston 3 and a second piston 4 are disposed in the pump chambers 1 and 2, respectively. These first piston 3 and second piston 4 are driven by a first motor 11 and a second motor 22, respectively. The rotational movements of the first motor 11 and the second motor 22 are converted into linear movements of the first piston 3 and the second piston 4 by the first plunger driving mechanism 23 and the second plunger driving mechanism 24, respectively. When the first motor 11 and the second motor 22 rotate forward, the first piston 3 and the second piston 4 are pushed out. When the first motor 11 and the second motor 22 rotate in the reverse direction, the first piston 3 and the second piston 4 are pulled in. In accordance with this reciprocation, the inlet side valve 5 and the outlet side valve 6 for backflow prevention open and close. By the operation of the first piston 3, the second piston 4, the inlet side valve 5, and the outlet side valve 6, the eluent 9 passes from the first pump chamber 1 into the second pump chamber 2, and the second pump chamber 2. The liquid is fed to the outlet side. According to the configuration of FIG. 2, since the motor is driven independently, the plunger position can be accurately controlled while providing a damping effect. Therefore, the flow rate system can be improved.

  As described above, according to the present embodiment, it becomes possible to continuously deliver the solvent in a stable manner with less pulsating flow, and the liquid chromatograph device has high sensitivity, improved qualitative ability, and reliability of quantitative results. Improvements can be made.

It is a schematic block diagram of the liquid feeding apparatus using the disc spring which is 1st embodiment of this invention. It is a schematic block diagram of the liquid feeding apparatus using the disc spring which is 2nd embodiment of this invention. It is a schematic block diagram of the liquid chromatograph containing the high pressure gradient liquid feeding apparatus comprised using two liquid feeding apparatuses of this invention, and a high pressure gradient liquid feeding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st pump chamber 2 2nd pump chamber 3 1st piston 4 2nd piston 5 Inlet side valve 6 Outlet side valve 7 First seal 8 Second seal 9, 27, 28 Eluent 10 Cam 11, 22 Motor 12 Detection plate 13 Position detection sensor 14 Control device 15, 17 Inlet port 16, 18 Outlet port 19 Pressure sensor 20, 21 Belleville spring (elastic member)
23 First plunger driving mechanism 24 Second plunger driving mechanism 25, 26 Liquid feeding device 29 T-shaped connection tube 30 Mixer 31 Sample introduction device 32 Separation column 33 Column oven 34 Detector 35 Data processing device

Claims (9)

A piston that reciprocates in a pump chamber having a liquid inlet and outlet, and a drive mechanism that controls the reciprocating motion of the piston;
A liquid feeding device for a liquid chromatograph that has a valve that prevents the liquid from flowing backward, and that feeds the liquid from the inlet to the outlet by a reciprocating motion of the piston,
The liquid feeding device, wherein the piston is connected to the drive mechanism via an elastic member that exerts an elastic force.   The liquid feeding device according to claim 1, wherein the elastic member is arranged on a straight line of the reciprocating motion of the piston. Liquid delivery device according to claim 1 or 2, characterized in that Ru provided with a cam which is the drive mechanism.   The liquid feeding device according to claim 1, wherein the elastic member is a disc spring.   The liquid feeding device according to claim 1, wherein the elastic member is a resin material. At least two pump chambers connected in series;
Liquid delivery device according to claim 1 or 2 more of the drive member control the reciprocating motion of each piston of the pump chamber and having a rotary shaft fixed. At least two pump chambers connected in series;
3. The liquid feeding device according to claim 1, further comprising a drive member for controlling the reciprocating motion of the piston for each piston of the pump chambers. A piston that reciprocates inside a pump chamber having a liquid inlet and outlet; a drive mechanism that controls the reciprocating motion of the piston;
A liquid chromatograph comprising a valve for preventing a back flow of the liquid, and a liquid chromatograph for feeding the liquid from the inlet to the outlet by a reciprocating motion of the piston,
The liquid chromatograph, wherein the piston is connected to the drive mechanism via an elastic member that exerts an elastic force .   The liquid chromatograph according to claim 8, wherein the elastic member is arranged on a straight line of reciprocal movement of the piston.

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