JPH04110656A - Liquid feeding apparatus for liquid chromatograph - Google Patents

Abstract

PURPOSE:To bring the apparatus back to the original liquid feeding state quickly by 'opening' an automatic drain valve when a CPU judges the defective liquid feeding, driving an auxiliary pump, and washing the inside of a main pump at a high flow rate. CONSTITUTION:When an auxiliary pump 4 is connected in series for a reciprocating plunger pump having a check valve for a main pump 1, liquid can be circulated in the inside even if the pump 1 is not operated. The liquid feeding state is detected with a CPU 8 based on the pattern of the pressure wave of a pressure sensor 14. When the defective liquid feeding is judged, an automatic drain valve 6 is 'opened', the pump 4 is driven, the inside of the pump 1 is washed at a high flow rate, the valve 6 is closed again and the original liquid feeding state is restored. The analysis is stopped until the recovery from the defective liquid feeding. When the valve 6 is 'opened', however, the liquid does not flow into an injector 16, a column 17 and the like. Even if the defective liquid feeding occurs, the original regular liquid feeding state can be restored quickly in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid feeding device for a liquid chromatograph, which is a type of analytical instrument.

[Conventional technology]

As shown in FIG. 6, a conventional liquid chromatograph liquid feeding device pumps up the mobile phase contained in a reservoir 10 with a main pump 13 and sends it to an injector via a pressure sensor 14 installed in the middle of piping and a manual drain valve 15. 16, column F, and is configured to send liquid in the direction of the detector 18.

In particular, if cavitation occurs in the mobile phase, it will cause poor liquid delivery and baseline noise in the detector, so the mobile phase should be subjected to a process such as deaeration (air removal) before being delivered.

In this figure, 11 and 12 are check valves.

In the liquid feeding device, when a liquid feeding failure occurs, a person opens the manual drain valve 5 one by one, operates the main pump 13 to the maximum flow rate, and removes air bubbles and cleans the pump. If there are parts that require manual labor, the liquid feeding unit cannot be automated, and there is also the problem that cleaning takes time.

[Problem to be solved by the invention]

As described above, when a large amount of air enters the conventional liquid feeding device, the main pump stops operating and the air cannot be expelled. Also, since a manual drain valve is used, cleaning takes time and the cleaning power is weak due to the low liquid flow rate (
However, the drawback is that it takes too much time to exchange the mobile phase.

This invention has been made to solve this problem.

(Means for Solving the Problems) Liquid delivery for liquid chromatograph comprising a main pump for delivering the mobile phase contained in a reservoir, and a pressure sensor and a drain valve disposed in the middle of piping from the main pump to the column. In the apparatus, an auxiliary pump driven by a motor is arranged in the middle of piping between the main pump and the reservoir, the drain valve is an automatic drain valve driven by a motor, and the motor of the main pump, the motor of the auxiliary pump, the pressure sensor, and the automatic It is characterized in that the drain valve motor is connected to a central processing unit.

[Function] In the means configured as described above, the main pump and the auxiliary pump are connected in series to send liquid. In this case, it is possible to circulate the mobile phase (liquid) inside even if the main pump does not operate.

The auxiliary pump is a diaphragm type with a check valve or a large syringe pump, but the overall flow rate is dominated by whichever has a larger flow rate, the main pump or the auxiliary pump. If a liquid feeding failure actually occurs, recovery is performed as follows.

First, the liquid feeding state is determined from the pressure wave pattern obtained by the pressure sensor to determine whether the liquid feeding is defective or not, and this is detected by the CPU. If it is determined that there is a failure in liquid delivery, the automatic drain valve is opened and the auxiliary pump is driven to flush out the inside of the main pump at a high flow rate. After rinsing, close the drain valve again to return to the original liquid supply state.

In addition, when replacing the mobile phase in the reservoir automatically or manually, (1) Open the automatic drain valve.

■ Operate the auxiliary pump for a certain period of time.

■Close the automatic drain valve.

The mobile phase can be replaced by this sequence.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a structural layout diagram of a liquid feeding device for a liquid chromatograph according to the present invention. Reference numeral 1 designates a plunger pump as a main pump, which is driven by a motor 2 to send liquid from a reservoir 3 containing a mobile phase toward a column 17. Reference numeral 4 denotes an auxiliary pump, which is driven by a motor 5. and the auxiliary pump 4
is installed in the middle of the piping between the plunger pump 1 and the reservoir 3. Further, the drain valve 6 installed between the pressure sensor 14 and the injector 16 is also an automatic drain valve driven by a motor 7. Reference numeral 8 is a central processing unit (hereinafter referred to as CPU), which is connected to the Bollinger pump 1.
The motor 2, the auxiliary pump 4, the motor 7 that drives the automatic drain valve 6, etc. are controlled. The auxiliary pump 4 may be a diaphragm pump, as shown in FIG. 2, or a large syringe pump, as shown in FIG. 3.

With the above configuration, the mobile phase is sent to the injector 16, column 17, and detector 18.

Next, the operation of this liquid feeding device will be explained.

In the mobile phase liquid delivery device with the above configuration, the main pump l is configured as a reciprocating plunger pump with a check valve, so
If another auxiliary pump 4 is connected in series to send the liquid, it is possible to circulate the mobile phase (liquid) inside the main pump 1 even if the main pump 1 does not operate.

As described above, the auxiliary pump 4 is a diaphragm type or a large syringe pump with a check valve, but the overall flow rate is controlled by whichever of the main pump 1 and the auxiliary pump 4 has a larger flow rate.

If a liquid feeding failure actually occurs, recovery can be done as follows.

The liquid feeding state is determined from the pressure wave pattern obtained by the pressure sensor 14 to determine whether the liquid feeding is defective or not, and this is detected by the CPU. If it is determined that there is a failure in liquid delivery, the automatic drain valve 6 is opened, and the auxiliary pump 4 is driven to flush out the inside of the main pump 1 at a high flow rate (usually about 50 ml/+in). After rinsing, close the drain HALPRO again and return to the original liquid feeding state. A flowchart of the above operations is shown in FIG. Although the analysis is suspended until the liquid feeding failure is resolved, the mobile phase does not flow to the injector 16, column 17, etc. by opening the automatic drain valve 6. During this time, the CPU 8 switches the detector 18 (
(not shown) may be turned on and off.

Furthermore, when replacing the mobile phase in the reservoir 3 automatically or manually, (1) Open the automatic drain valve.

■ Operate the auxiliary pump 4 for a certain period of time.

- Close the automatic drain valve 6.

The mobile phase may be replaced by the following sequence.

Note that when cleaning the main pump 1 and the like, there are cases where a solvent with strong cleaning power is used. In that case, as shown in Figure 5, the switching valves ■1, ■2, and ■3 are installed in front of the auxiliary pump 4
etc. may be provided so that automatic cleaning may be performed after switching the valve and replacing the liquid. Although the main pump 1 is shown as a single plunger pump, it may be a parallel or series double plunger pump.

One embodiment of the present invention has been described above, but as a further modified embodiment, when the main pump 1 is delivering high-pressure liquid, the auxiliary pump 4 is operated at an appropriate flow rate to apply back pressure to the main pump 1. Cavitation of the main pump 1 may be prevented by providing the same. Furthermore, the dead volume on the inlet side of the main pump 1 may be reduced by installing the auxiliary pump 3 at the outlet of the automatic drain valve 6.

[Effects of the Invention] Since the liquid delivery device for liquid chromatography according to the present invention has the configuration described in detail above, even if bubbles occur in the main pump or a liquid delivery failure occurs, the original normal delivery can be quickly restored. It can be returned to a liquid state. Furthermore, it is possible to perform automatic cleaning with appropriate cleaning power, and when necessary, the type of solvent can be automatically switched for cleaning. This makes it extremely convenient.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a liquid feeding device for a liquid chromatograph according to the present invention, Fig. 2 is a separate view in which the auxiliary pump in Fig. 1 is a diaphragm pump, and Fig. 3 is a diagram in which the auxiliary pump in Fig. 1 is used as a syringe pump. Figure 4 is a flowchart showing a case where the main pump in the liquid feeding device according to the present invention is restored to normal condition, and Figure 5 is a diagram showing the main pump of the liquid feeding device according to the present invention. Layout diagram of the mobile phase and cleaning solution when cleaning with a strong solvent,
FIG. 6 is a diagram showing the arrangement of a liquid feeding device of a conventional liquid chromatograph. 1.-Main pump 2.5.7-Motor 3-Reservoir 4-Auxiliary pump 6.-Automatic drain buffer s-c pu14.
...Pressure sensor 17--Column 18--Detector Applicant Shimadzu Corporation Representative Patent attorney Maki Kawasaki

Claims (1)

[Claims] (1) A main pump that pumps the mobile phase contained in the reservoir;
In a liquid chromatograph liquid feeding device comprising a pressure sensor and a drain valve disposed in the middle of piping from the main pump to the column, an auxiliary pump driven by a motor is disposed in the middle of the piping between the main pump and the reservoir, and the For a liquid chromatograph, the drain valve is an automatic drain valve driven by a motor, and the main pump motor, the auxiliary pump motor, the pressure sensor, and the automatic drain valve motor are connected to a central processing unit. Liquid feeding device.