JPH0422295Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure sensor for liquid chromatography.

[Conventional technology]

As shown in the flow sheet of FIG. 5, a conventional chromatograph has a piping system in which the solvent is sucked in via an air trap 2 by a liquid pump 1 such as a plunger-type high-pressure pump, and the solvent is transferred to the outlet of the liquid pump 1. The liquid is branched into two at a branch joint 4 via a liquid feeding line 3 connected to the side, and is fed to a pressure measurement line 6 connected to a pressure sensor 5 and an injector line 8 connected to an injector 7 for sampling, From the injector 7, the sampling loop 7a or 7
b, mixed with the sample metered in by 7c,
Generally, the configuration is such that the light is sent to an ultraviolet absorption detector 10 or the like via a column 9.

In addition, in general liquid chromatographs, liquid feeding may not start when the liquid feeding pump 1 is started, or the liquid feeding pump 1 may stop feeding during analysis work. 1
Air bubbles adhere to the check valve of the liquid pump 1, which prevents the liquid from being fed.To return to normal operation from this state, open the discharge side of the liquid feed pump 1 and remove the liquid from the liquid pump 1. Normal operation was made possible by flushing out air bubbles with solvent head pressure or suctioning the pump head with a syringe from the open area to fill the pump head with liquid. Therefore, in the conventional piping system, a drain valve 11 is provided on the downstream side of the pressure sensor 5 located on the discharge side of the liquid pump 1 so that it can be opened, and the syringe 1
It enabled suction by 2.

[Problem that the invention attempts to solve]

However, since the drain valve 11 is located at the end of the line passing through the liquid supply line 3, branch joint 4, pressure measurement line 6, and pressure sensor 5, the distance from the liquid supply pump 1 is long and the syringe 12 had poor suction efficiency.

In addition, the drain valve 11 is opened to clean the flow path of the piping system when changing the solvent, so the simpler and shorter the piping system is, the better. Moreover, the provision of the drain valve 11 made the piping system complicated and long.

Furthermore, since the branch joint 4, the pressure sensor 5, and the drain valve 11 are provided, there is a problem in that dead volumes in which solvent and the like accumulate tend to be formed at each connection portion.

The present invention was developed in view of the above points, and by integrating the branch joint and drain valve mechanisms, it is possible to reduce the number of parts, shorten the piping system, and reduce the number of connecting parts of the pipes that cause dead volume. The aim is to provide a pressure sensor that can

[Means for solving problems]

As a means to solve the above problems, the present invention provides a pressure sensor that is installed at one end of the piping system of a liquid chromatograph and is interposed between the liquid feed pump and the injector to detect the pressure within the piping system. A main flow path that communicates from the connection port of the liquid feed line from the liquid feed pump through the hydraulic pressure chamber where pressure is detected to the connection port of the injector line at the other end, which is formed so that a line filter can be set; It is characterized in that it can be opened and closed by a needle valve, and also has a drain flow path that connects to the end of the tube for syringe suction and communicates with the hydraulic pressure chamber.

〔Example〕

An embodiment of the pressure sensor according to the present invention will be described below with reference to FIGS. 1 to 4.

The cylindrical pressure sensor 20 includes a sensor section 22 containing a pressure sensor 21 and a liquid introduction section 23 that forms a flow path.
The liquid introduction section 23 is composed of the sensor section 2
2, the recess 24 is recessed from the front side of the pressure sensor 2, and the bottom 24a thereof is located very close to the pressure sensor 21.
, screw the mounting part 23a into the
The end surface of the recess 24 is mounted so that the end surface of the recess 24 is in close contact with the bottom 24a of the recess 24, and the center of the bottom 24a of the recess 24 is formed circularly and one step lower, so that a hydraulic chamber 25 is formed between the end surfaces of the mounting portion 23a. is defined.

A liquid feeding line connection port 28 to which a liquid feeding line 27 is connected is provided on the outer peripheral surface of the liquid introducing portion 23 that protrudes to the outside when the pressure sensor 20 is attached to the housing panel 26 surface of the main body of the liquid chromatograph apparatus. and an injector line connection port 30 for connecting the injector line 29 via the adapter 29a.
are formed at opposing positions with the center in between, and a liquid feeding line 27 is formed at the back of this liquid feeding line connection port 28.
A tapered surface 28a is formed in the inner part of the injector line connection port 30 to fit the line filter 32 into it, and a tapered surface 28a is formed in the inner part of the injector line connection port 30 to press the metal ferrule 31 at the connection end of the injector line connection port 30 for sealing. At the bottom of the connection ports 28 and 30, there is a bottom 24a of the recess 24 formed in the sensor section 22.
A main flow path 28b on the liquid feeding line 27 side and a main flow path 30b on the injector line 29 side are formed, which communicate with the circular hydraulic pressure chamber 25 defined between the end faces of the mounting portion 23a of the liquid introduction portion 23. It has been done.

Further, in the center of the front surface of the liquid introduction part 23, an insertion opening 34 into which a needle valve 33 functioning as a drain valve is inserted is formed in the axial direction so as to communicate with the hydraulic pressure chamber 25. The needle portion 33a of the needle valve 33 is seated in the intermediate portion of the insertion port 34, and a tapered valve seat portion 34a that blocks communication with the hydraulic pressure chamber 25 is formed.
A drain flow path 35 is formed in communication on the front side of the valve seat portion 34a, and the drain flow path 35 opens at an intermediate portion between the liquid feed line connection port 28 and the injector line connection port 30 on the outer peripheral surface of the liquid introduction portion 23. Road 35
At the end of the suction tube connection port 3 is connected to a suction tube 36 using a syringe (not shown).
7 is formed.

Note that 38 is a seal ring that seals the peripheral edge of the hydraulic pressure chamber 25, 39 is a lead wire bundle led out from the sensor section 22, and 40 is a nut that fixes the pressure sensor 20 to the device.

As shown in the flow sheet of FIG. 4, the pressure sensor 20 configured as described above has a liquid feeding pump 41 such as a plunger-type high-pressure pump in the piping system of a liquid chromatograph and an injector 42 for introducing a sample. The pressure sensor 20 detects the pressure of the solvent sucked from the solvent storage tank 43 via the air trap 44 by the liquid feeding pump 41 and flows through the piping, and branches the piping system into two at the pressure sensor 20. One side is connected to a syringe suction tube 36 from a drain passage 35 with a needle valve 33 interposed therebetween.
The other line becomes an injector line 29 and is connected to an ultraviolet absorption detector 46 via an injector 42 that introduces the sample and a column 45, and in conventional liquid chromatographs, each line is connected by piping using independent parts. The branch joint and drain valve are integrated with the pressure sensor to create a simple piping system.

[Effect of idea]

As explained above, the chromatographic pressure sensor according to the present invention is configured such that a line filter can be set through the hydraulic pressure chamber for pressure detection from the connection port of the liquid feeding line from the liquid feeding pump formed at one end. a main flow channel that communicates with the connection port of the injector line at the other end, and a drain flow channel that can be opened and closed by an interposed needle valve and that a tube for syringe suction can be connected to the end and that communicates with the hydraulic pressure chamber. By providing a pressure sensor that incorporates the branch joint and drain valve, which were conventionally separate separate parts, the piping system can be shortened and the number of parts interposed in the piping system can be reduced. This has the effect of reducing the number of piping connections where dead volume is likely to occur, and reducing costs.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is a perspective view of a pressure sensor, Figure 2 is a partially sectional front view, and Figure 3 is a pressure sensor with a needle valve removed. A side view of the sensor, Figure 4 is a flow sheet showing the chromatograph piping system when using the pressure sensor according to the present invention, and Figure 5 shows the chromatograph piping system when using the conventional pressure sensor. It is a flow sheet. 20...pressure sensor, 21...pressure sensor, 22...
...Sensor part, 23...Liquid introduction part, 24...Recessed part,
25... Hydraulic pressure chamber, 27... Liquid feeding line, 28...
Liquid feeding line connection port, 28a...Tapered surface, 28b
... Main channel, 29 ... Injector line, 30
...Injector line connection port, 30a...Filter storage section, 30b...Main flow path, 32...Line filter, 33...Needle valve, 34...Insertion port, 35...Drain channel, 36... Suction tube, 37... Suction tube connection port, 42...
Injector, 45...column, 46...ultraviolet absorption detector.

Claims (1)

[Scope of utility model registration request] A pressure sensor is installed between a liquid feeding pump and an injector in a liquid chromatograph piping system and detects the pressure within the piping system. There is a main channel that communicates with the injector line connection port at the other end through the hydraulic pressure chamber where a line filter can be set, and an interposed needle valve that allows for opening and closing, and a syringe suction port at the end. A pressure sensor for a liquid chromatograph, characterized in that a tube can be connected thereto and a drain flow path communicating with the liquid pressure chamber is provided.