JPS5830217Y2 - chromatography pump - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a liquid pump for chromatography.

There are two conventional types of liquid pumps for chromatography.

One of them is cam by motor. One type drives the plunger through a mechanism such as a crank, and the other type drives the plunger by applying fluid pressure to the back surface of the plunger.

The present invention is particularly concerned with improving this latter type of pump, and aims to provide a liquid pump with extremely low pressure fluctuations.

FIG. 1 shows a conventional example of a chromatography pump in which a plunger is driven by fluid pressure.

Pl is a large-area piston that is fitted into the cylinder C1, and the piston P1 is connected to a small-area plunger P2 by a connecting rod, which is fitted into the cylinder C2.

Vl and V2 are valves for supplying or blocking pressurized fluid (air is often used) into the cylinder C1;
V3. V4 is a valve for discharging the fluid in the cylinder C1. These valves are electromagnetic valves, and if these valves are controlled to alternately introduce fluid to both sides of the piston P1, the piston P1 moves left and right.

Along with this, plunger P2 also moves, and by moving to the right, carrier fluid R for chromatography is sucked into cylinder C2 through check valve S1, and by moving P2 to the left, this sucked fluid is forced open the check valve SV2 and is pumped into the column.

The pressure of the fluid sent to the column is increased by the area ratio of the plungers PI and P2 compared to the pressure of the fluid that drives the piston P1.

In this pump, the friction of the contact surface between the piston P1 and the cylinder C1, which have a particularly large area, causes fluctuations in the discharge pressure of the pump.

When using gas as the pressurized fluid applied to piston P1, the compressibility of gas is high, so when pushing an object against frictional force using such an elastic medium, the principle of so-called self-excited vibration is used. Since nodal movement occurs in the discharge pressure, fluctuations in the discharge pressure become large.

In contrast to the conventional pump described above, in the present invention, the parts corresponding to the piston P1 and cylinder C1 in FIG. 1 are made into flexible volume variable bodies such as bellows to completely eliminate the influence of friction.

The present invention will be explained below with reference to Examples.

FIG. 2 shows an embodiment of the chromatography pump of the present invention.

Bl, B2. B3. B4 is a bellows.

B1 is the main bellows and has the largest cross-sectional area, and bellows B3
．． B4 is for pushing back the main bellows B1 and has a small cross section.

The bellows B2 is a bellows for pushing the carrier fluid into the suction column, and is connected to the main bellows B1 by a connecting rod K, and is driven to expand and contract by B1.

The cross-sectional area of B2 is smaller than the cross-sectional area of B1 so as to obtain a predetermined pressure increase.

In a pump, the effective action area is the value obtained by dividing the amount of fluid ejected by the moving distance of the driving part (plunger or bellows).In the case of a bellows, this is approximately equal to the maximum cross-sectional area, and the liquid delivery pressure is the effective action area. The pressure of the driving gas is increased by the area ratio.

Bellows B1 is connected to a pressurized fluid source via solenoid valve ■1, and a branch pipe comes out between B1 and ■1 and opens to the atmosphere, and solenoid valve ■3 is inserted into this branch pipe. be.

Bellows B1 and B3. B4 is opposed to B4 via arm A, and between arm A and the left end of B1 and the bellows B3. Balls Gl and G2 are interposed between B4 and arm A, respectively.

Bellows B3. B4 is connected to the same pressurized fluid source as B1 via a solenoid valve V2, and also to the atmosphere opening via a solenoid valve 4.

Arm A and the connecting rod are integral.

The pipe T connected to the bellows B2 splits into two, one leading to the carrier fluid reservoir R via a downwardly opening check valve SVI, and the other to the column via a downwardly opening check valve SV2. There is.

Now solenoid valve V3. When V2 is closed and Vl and V4 are opened, pressurized fluid flows into the bellows B1, causing B1 to expand.

Next, V3. When V2 is opened and Vl and V4 are closed, bellows B3. Pressurized fluid flows into B4, B3°B4 expands and compresses bellows B1, and the fluid in B1 is discharged through solenoid valve 3.

As the bellows B1 expands and contracts, the bellows B2 also expands and contracts, and when it expands, it sucks in the carrier liquid from R, and when it is compressed, the sucked-in carrier liquid is sent to the column through the SV2.

In the above embodiment, the part that directly pumps the carrier fluid is the bellows B2, but if the pressure resistance of the bellows is a problem with respect to the required carrier pressure, the part B2 is replaced by the part P2 in FIG. It may also be a plunger and cylinder like C2.

The cause of the pressure fluctuation is mainly the friction between the plunger P1 and the cylinder C1 shown in FIG.

As mentioned above, the chromatography pump of the present invention uses a flexible volume variable body such as a bellows instead of a plunger and cylinder, but there is no friction at all, and the pressure change caused by this friction is eliminated, resulting in an extremely stable carrier. Fluid pressure can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a conventional chromatography pump, and FIG. 2 is a side view showing an embodiment of the present invention. B1. B2. B 3. B4...Bellows, Vl, V2. V3, ■4...Solenoid valve, R...
...Carrier fluid reservoir, SVI. SV2・・・・・・Check valve.

Claims (1)

[Scope of utility model registration request] A bellows having an effective action area larger than the effective action area of the liquid delivery pump is connected to a pressurized fluid source via an on-off valve, and the bellows is connected to the movable part of the liquid delivery pump, and the bellows is expanded and contracted. A chromatography pump configured to drive the liquid feeding pump.