JPH0736057U - HPLC pump - Google Patents

Abstract

(57) [Summary] [Constitution] The HPLC pump according to the present invention has a pump chamber 120 through which a solution flows, and an upper and a lower portion of the pipe for controlling the flow of the solution in the pump chamber only to an upward flow. Check valves 124 and 126 arranged, and a piston 122 arranged between the check valves 124 and 126, for sucking the solution through the lower check valve 126 and discharging the solution through the upper check valve 124,
In the HPLC pump provided with, the check valves 124 and 126 include balls 128 and 130 and a valve seat 13
2, 134, the specific gravity of the balls 128, 130 is 4 or more, and at least the surface of the balls is covered with ceramic. [Effect] Since the specific gravity of the ball is large, the opening / closing operation of the check valve can be performed quickly and with good reproducibility. Furthermore, the durability of the check valve is excellent because the surface of the ball is covered with ceramic.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an HPLC pump, and more particularly to an improvement of its check valve.

[0002]

[Prior art]

 Recently, various carriers are used as a stationary phase, and a sample to be separated is moved from one end of the stationary phase as a mobile phase together with a solvent, and the difference in the transfer rate based on the difference in the adsorptivity of the sample or the separation coefficient is measured. HPLC for separating a sample by utilizing is widely used, and a means for identifying and quantifying the separated sample with a UV detector is used. When performing the above-mentioned HPLC, a solvent containing a sample as a mobile phase is sucked up from below by using a pump and fed into a closed column. The pump includes a pump chamber, a check valve provided on the pump chamber, and a piston that reciprocates in the pump chamber. The reciprocating motion of the piston opens and closes the check valve, and a fixed amount of mobile phase is sent from the pump chamber to the column.

Here, what is important in HPLC is that the retention time must be accurately reproducible, and if the reproducibility of the retention time is deviated, accurate sample identification and quantification cannot be performed. Will end up. In order to accurately perform the retention time reproducibility, it is necessary that the opening / closing operation of the check valve is performed quickly and the flow rate reproducibility of the mobile phase from the pump to the column is excellent. Therefore, the conventional check valve is configured as shown in FIG. 4, and includes a ball 10, a valve seat 12, and a spring 14.

In the check valve shown in FIG. 1, the ball 10 is placed on the valve seat 12, and the check valve is opened when the ball 10 is separated from the valve seat 12, and the ball 10 and the valve seat 12 are opened. The mobile phase flows from between, and the check valve is closed while the ball 10 is in contact with the valve seat 12, and the flow of the mobile phase is stopped. Ruby is generally used as the material of the ball 10. However, since the ruby has a relatively small specific gravity of 3.5 to 3.9, the ball 10 is separated from the valve seat 12. Since it takes time from the open state where the ball 10 is in contact with the valve seat 12 to the closed state, the flow rate reproducibility deteriorates.

Therefore, as shown in FIG. 4, a metal spring 14 is provided between the ball 10 and the ball housing 16, and pressure is applied to the ball 10 toward the valve seat 12 to open the check valve from the open state to the closed state. The operation of the ball 10 until it reaches the limit is accelerated, and flow rate reproducibility is improved.

[0006]

[Problems to be solved by the device]

 However, the structure of the check valve described above has a problem that it is difficult to assemble because it has the spring 14. Further, since the material of the spring 14 is metal, when the mobile phase is a halogen-based solvent, the spring 14 is corroded and there is a problem in durability.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an HPLC pump that is easy to assemble, has excellent durability, and has a quick check valve opening / closing operation.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, an HPLC pump according to the present invention includes a pump chamber in which a solution flows and an upper and lower part of the pump chamber that controls only the upward flow of the solution in the pump chamber. A HPLC pump comprising: a check valve that is arranged; and a piston that is arranged between the check valves and that sucks the solution through the lower check valve and discharges the solution through the upper check valve. The check valve has a ball and a valve seat, the specific gravity of the ball is 4 or more, and at least the surface of the ball is covered with ceramic.

[0009]

Since the HPLC pump according to the present invention has the above-mentioned means, since the specific gravity of the ball is large, the ball is actuated quickly from the open state to the closed state of the check valve, and the flow rate reproducibility is improved. . Further, since the surface of the ball is covered with ceramic, the ball has excellent durability, and since a spring is not required, the assembly can be easily performed.

[0010]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration explanatory view of an HPLC pump according to the present invention. The HPLC pump shown in the figure includes a pump chamber 120, a piston 122, a first check valve 124, and a second check valve 126. Further, inside the pump chamber 120, a piston 122 is provided, which is kept airtight with the outside by a seal 200. The first check valve 124 and the second check valve 126 are arranged above and below the pump chamber 120.

Further, each of the first check valve 124 and the second check valve 126 has a first ball 128 and a second ball 130, and a first valve seat 132 and a second valve seat 134, respectively. ing. Here, the material of the first ball 128 and the second ball 130 is zirconia ceramic. When the piston 122 is stopped, the first ball 128 and the second ball 130 are in contact with the first valve seat 132 and the second valve seat 134, respectively, and the first check valve 124 and the second check valve 124 Both check valves 126 are closed. When the piston 122 moves in the direction away from the pump chamber 120, that is, to the right in FIG. 1, only the second ball 130 separates from the second valve seat 134 and the second check valve 126 is opened. Therefore, the mobile phase is sucked up into the pump chamber 120 from below the second check valve 126. Further, when the piston 122 moves in the direction opposite to the above direction, that is, to the left in FIG. 1, the second ball 130 again contacts the second valve seat 134 and the second check valve 126 is closed, and conversely, the first ball 128 moves. The first check valve 124 is opened from the first valve seat 132. Therefore, the mobile phase sucked into the pump chamber 120 is sent above the first check valve 124. By repeating the constant reciprocating motion of the piston 122, a constant amount of mobile phase is sucked up from below the second check valve 126 into the pump chamber 120 and sent above the first check valve 124. The flow of the mobile phase is repeated.

Here, the specific gravity of the first ball 128 and the second ball 130 is 5.6 to 5. Since the zirconia ceramic of No. 9 is used, the first ball 128 and the second ball 130 have the first valve seat 132 and the second ball 130 as compared with the case of using the conventional ruby having the specific gravity of 3.5 to 3.9. The operation from the state where the valve is separated from the valve seat 134 to the state where it is in contact, that is, the state where the first check valve 124 and the second check valve 126 are opened to closed is performed quickly. Therefore, the flow rate reproducibility is improved and the retention time reproducibility of HPLC is also improved when using zirconia ceramics as compared to when using ruby, so that accurate sample identification and structural analysis can be performed. . Moreover, since zirconia ceramics are chemically stable and have excellent corrosion resistance, they do not cause corrosion unlike the conventional example using a spring.

Next, the specific operation of the HPLC pump according to the present invention will be described. Comparing the GPC chromatogram using THF (tetrahydrofuran) as a solvent with the pump using ruby for the first ball 128 and the second ball 130 and the pump using zirconia ceramic, the retention time reproducibility was found. It improved from 0.1% when ruby was used to 0.07% when zirconia ceramic was used. Furthermore, self-priming from a solvent bottle 80 cm below the pump through an empty inlet tube was not possible with rubies, but was possible with zirconia ceramics. When n-hexane, which is a low-viscosity solvent, is sent, the pressure waveform as shown in Fig. 2 is measured in the pump using ruby, and the pressure waveform in Fig. 3 is measured in the pump using zirconia ceramic. The waveform was measured. As is clear from the figure, it is understood that the zirconia ceramic pump has less pulsation and the pressure waveform reproducibility is superior to the ruby pump.

From the above, it is understood that the pump using zirconia ceramic is superior in the stability of the check valve opening / closing operation and the flow rate reproducibility to the pump using rubies. Moreover, the ceramics, which is a sintered body, has less directionality than the ruby, which is a single crystal. Therefore, the accuracy of polishing is increased and the sphericity is increased. The higher the sphericity, the better the ball-valve seat sealing function. In this embodiment, an example in which the entire ball is made of zirconia ceramics has been described, but for example, a high specific gravity metal sphere may be used in the central portion and a corrosion resistant ceramic layer may be provided thereon.

[0015]

[Effect of device]

 As described above, according to the HPLC pump of the present invention, since the specific gravity of the ball is large, the opening / closing operation of the check valve can be performed quickly and with good reproducibility, and further, the surface of the ball is covered with the ceramic. Excellent durability of check valves

[Submission date] March 2, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

[Effect of device]

 As described above, according to the HPLC pump of the present invention, since the specific gravity of the ball is large, the opening / closing operation of the check valve is performed quickly and with good reproducibility, and further, the surface of the ball is covered with the ceramic. The durability of the check valve is also excellent.

[Brief description of drawings]

FIG. 1 is an explanatory view of a configuration of an HPLC pump according to the present invention.

FIG. 2 is an explanatory diagram of a pressure waveform of a pump using a ruby ball as a check valve.

FIG. 3 is an explanatory diagram of a pressure waveform of a pump using a zirconia ceramic ball as a check valve.

FIG. 4 is an explanatory diagram of a configuration of a conventional check valve.

[Explanation of symbols]

 120 pump chamber 122 piston 124,126 check valve 128,130 ball 132,134 valve seat

[Procedure amendment]

[Submission date] March 2, 1994

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Added

[Correction content]

[Brief description of drawings]

FIG. 1 is an explanatory view of a configuration of an HPLC pump according to the present invention.

FIG. 2 is an explanatory diagram of a pressure waveform of a pump using a ruby ball as a check valve.

FIG. 3 is an explanatory diagram of a pressure waveform of a pump using a zirconia ceramic ball as a check valve.

FIG. 4 is an explanatory diagram of a configuration of a conventional check valve.

[Explanation of reference numerals] 120 pump chamber 122 pistons 124, 126 check valve 128, 130 ball 132, 134 valve seat

Claims (1)

[Scope of utility model registration request] 1. A pump chamber through which a solution flows, check valves arranged above and below the pump chamber for controlling only the upward flow of the solution in the pump, and between the check valves. A piston for HPLC, which is arranged and sucks the solution through the lower check valve and discharges the solution through the upper check valve, wherein the check valve has a ball and a valve seat, and A HPLC pump, characterized in that the ball has a specific gravity of 4 or more, and at least the surface of the ball is covered with a ceramic.