JPH06229997A - Low pressure gradientor - Google Patents

Abstract

PURPOSE:To provide an apparatus which enables the suction of two liquids from one pump accurately and effectively in a low pressure gradientor which is adapted to mix the two liquids varying the concentration thereof as set beforehand. CONSTITUTION:This apparatus mixes two liquids at an arbitrary ratio and feed liquid passages 3 and 4 are linked to one closed type mixer bin 2 from the respective liquids and solenoid valves 8 and 9 are provided on the respective feed liquid passages 3 and 4 having check valves 10 and 11 in the vicinity thereof to suck the two liquids alternately switching the passages. A piston pump 5 is provided at a downstream point of the mixer bin 2. The mixer bin 2 has end parts of feed liquid passages 3 and 4 at a position above the body of the apparatus to facilitate the feeding of bubbles generated in the bin as intact to the subsequent process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pressure granulator in which, when two liquids are mixed, if the mixing ratio is set in advance, one pump can perform suction according to the set ratio from each liquid container. Is related to the structure of.

[0002]

In the field of liquid chromatography,
It is often necessary to mix two liquids (for example, liquid A and liquid B) at a certain arbitrary ratio (for example, 3: 1) by a liquid feed pump. In that case, when the required amount of the mixed solution is predetermined (for example, 1 liter), it is easy (take 0.75 liter of solution A, and add 0.25 liter of solution B here and stir). Further, when the operation time of the pump is fixed (for example, 4 minutes), it is easy (the solution A is first sent for 3 minutes, and then the solution B is sent for 1 minute).

However, when the mobile phase is to be pressed into the column as a mixed solution, it is often recognized in advance that only the mixing ratio of the two solutions. In addition, in most cases, there is no time or space to start injection of the liquid once the required amount of the mixed liquid has been created. There are many problems in post-treatment of liquid.

Therefore, the most suitable method is to prepare a mixer bottle having a small capacity and to feed the two liquids to the column while putting the two liquids therein. Therefore, conventionally, a method has been adopted in which the two pumps capable of changing the flow rate ratio individually suck the liquids A and B and send the liquids to the mixer bottle.

This mixer bottle is a small container for storing the mixed liquid, and once stored, it is well stirred and prepared for the next step such as column press-fitting.

On the other hand, the liquid feed pump used in such an apparatus requires a small capacity in the pump, can continuously perform discharge, is inexpensive, and is independent of pressure drop throughout the flow path system. It is often a piston pump because of the fact that a constant flow is obtained. Then, in this case, since the pump feeds the liquid by the valve while sucking and discharging, the flow naturally becomes a pulsating flow. Therefore, if you want to create a mixed liquid by suctioning from two liquids at an arbitrary ratio, use one pump,
A method of switching the liquid to be sucked at a time cycle corresponding to the ratio does not work well.

Therefore, as a measure capable of mixing and feeding two liquids with one piston pump, a method of providing a switching valve for each of the two liquids and alternately feeding the liquids by switching between them can be considered. In this case, it has been found that the pulsating flow works properly by adjusting the intake / exhaust cycle of the piston pump and the switching cycle of the switching valve and dividing the switching cycle according to the set ratio.

[0008]

As a result of various experiments, it has been found that even when the set concentration should theoretically be set, the proper mixing ratio may not be obtained in some cases. The reason for this will be described to the extent that the present inventor thinks. Now, consider a situation in which the two liquids A and B are stored in the mixer bin 24 from the respective containers 20 and 22 by alternately opening and closing the solenoid valves 21 and 23 (FIG. 2).
The mixer bin 24 is sealed. Therefore, the liquid delivery in the area shown in the figure can be performed by one piston pump 26 located on the tube 25 downstream of the mixer bin 24.

As described above, since the piston pump 26 delivers liquid by pulsating flow, the tube 2
There is a periodic fluctuation in the pressure of the mixed liquid in 5,
The depressurization is repeated.

On the other hand, when the two liquids are mixed, depending on the types, they may react with each other to generate bubbles. Of course, two kinds of liquids that generate a large amount of gas are not suitable for use because there is a risk of putting gas in the column, but they are often used in the case of generating a very small amount of gas. . This is because the pressure during column injection is very high,
This is because the gas will not dissolve in the liquid and will not be an obstacle.

However, the high pressure is generated on the downstream side of the pump and is low on the upstream side. Then, the gas remains as bubbles. Then, as described above, due to the periodic fluctuation of the pressure due to the pulsating flow, the bubbles become larger or smaller.

Then, in the mixer bottle 24 which is sealed and filled with the liquid, the interface changes up and down according to the volume change of the bubble through the tube following the liquid on the open side of the solenoid valve due to the change of the volume of the bubble. .

One of the pumps commonly used in such devices
Since the amount of liquid sent per cycle is small, the occurrence of an error due to this volume change has a great influence on the ratio. In addition, there is a problem that the vibration of the interface is only on the side where the solenoid valve is open, and the ratio on this solenoid valve side is small (that is, the solenoid valve opens for a shorter time than the other solenoid valve). However, if the bubbles are just large at the time of opening, it is possible that the liquid does not enter the mixer bottle even though the pump is sucking.

[0014]

SUMMARY OF THE INVENTION The present inventor has finally made the present invention as a result of years of intensive research in view of the above-mentioned points, and the mixing of two liquids according to a set ratio using one piston pump,
It is possible to transfer liquid to the next step, and the feature is that it mixes two liquids at an arbitrary ratio, and transfers each liquid to one closed mixer bottle. The flow paths are connected and the individual flow paths are switched to
Solenoid valves for alternately sucking each of the liquids are provided in the individual liquid feeding flow paths, and downstream of the mixer bin,
Piston pumps for delivering these liquids and liquids to the next stroke are arranged, and check valves are provided in the respective liquid delivery passages in the vicinity of the solenoid valves and at the downstream positions of the solenoid valves. Is provided.

The mixer bottle used in the present invention is located between the piston pump and the container for the two liquids, and the liquid is introduced into the mixer bottle by the pump. It is a type. Further, it is not preferable that the mixed or generated air bubbles be stored, and it is necessary to prevent this, but the end of the liquid supply flow path to the next process should be prevented so that the small air bubbles can be sent to the next process. Is preferably arranged at or near the opening position above the main body.

[0016]

The present invention will be described in more detail with reference to the drawings.

FIG. 1 schematically shows an example of a low-pressure gradient 1 according to the present invention (hereinafter referred to as the inventive gradient 1). As is apparent from the figure, the inventive gradient 1 is A, A container containing each B2 solution,
The liquid supply flow paths 3 and 4 connecting these to the mixer bin 2 and the liquid supply flow path 6 connecting the mixer bin 2 and the pump 5 are provided. If any mixing ratio is set in, the solenoid valves 8 and 9 that open and close at a ratio corresponding thereto, and the check valve 1 at a downstream position in the vicinity of these solenoid valves are provided.
0 and 11 are installed.

The setting of an arbitrary mixing ratio to the input section 7 is the initial concentration and the final concentration, the initial concentration holding time and the gradient time, the final concentration holding time, etc., as in the conventional gradient. Since these are not the main part of the present invention, they will not be described in detail.

The solenoid valves 8 and 9 are switched alternately based on the settings made in this way. Therefore, the valve is always open only on one side.

The mixer bottle 2 is of a closed type and is constantly filled with liquid. Further, the liquid supply flow paths 3 and 4 connected to the container containing the two liquids reach near the bottom of the mixer bottle 2. The end of the other liquid supply flow path 6 is located at the upper end position of the mixer bin 2. This positional relationship at the end of each flow path is the reverse of that of the conventional mixer bin, but this is for the gas mixed in or generated in the bin to be delivered in the form of small bubbles. This is a device for sending it to the next step from the path 6, and this makes it possible to prevent the gas of a volume that hinders liquid suction from remaining in the mixer bin 2.

[0021]

As described in detail above, the present invention has two advantages.
A device for mixing liquids at an arbitrary ratio, each liquid flow path being connected to one closed mixer bin from each liquid, and switching between the individual flow paths to alternately suck each of the two liquids. An electromagnetic valve for performing the above is provided in each liquid feed passage, and a piston pump for feeding these liquids and the liquid for the next stroke is arranged downstream of the mixer bin. A check valve is provided in the vicinity of the solenoid valve in the liquid feeding flow path of, and at a position downstream of the solenoid valve, respectively, which has various effects as described below. It is an advanced invention. Since one piston pump can mix two liquids,
It is easy to reduce the cost and size of the device. Since the check valve is provided, the mixed liquid does not flow back into each of the liquid feeding flow paths, so that an accurate mixing ratio can be easily obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a low pressure gradient according to the present invention.

FIG. 2 is a schematic diagram for explaining the necessity of providing a check valve.

[Explanation of symbols]

 1 Low-pressure grater 2 Mixer bin 3 A liquid feed passage 4 B liquid feed passage 5 Piston pump 6 Mixed liquid feed passage 7 Input part 8 A liquid side solenoid valve 9 B liquid side solenoid valve 10 A liquid side Check valve 11 B liquid side check valve

Claims (2)

[Claims] 1. A device for mixing two liquids at an arbitrary ratio, wherein liquid-feeding flow passages are connected to one closed mixer bottle from each liquid, and the individual flow passages are switched to change the liquid flow passage.
Solenoid valves for alternately sucking each of the liquids are provided in the individual liquid feeding flow paths, and downstream of the mixer bin,
Piston pumps for delivering these liquids and liquids to the next stroke are arranged, and check valves are provided in the respective liquid delivery passages in the vicinity of the solenoid valves and at the downstream positions of the solenoid valves. A low-pressure gradient is provided. 2. When mixing the two liquids at an arbitrary ratio,
A mixer bottle which is connected to each of the liquids by a liquid supply flow path and also has a liquid supply flow path to the next step, wherein an end of the liquid supply flow path to the next step is arranged at a position above the main body. A mixer bottle for a low-pressure grater that is characterized by being