JPH0442776Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is useful, for example, when collecting a predetermined amount of liquid sample and supplying it to an analytical instrument, etc. in order to analyze a liquid sample. This invention relates to a liquid sample supply device.

[Prior art]

Generally, it is often necessary to take a predetermined amount of a liquid sample and add it to the sample. For example, the Karl Fischer automatic titrator is known as a typical automatic moisture analyzer that automatically analyzes trace amounts of moisture in liquid samples. There is a need to.

For this purpose, in the past, a delivery gas supply mechanism was connected to the sample feed tube for supplying the liquid sample via a rotary valve, etc., and a fixed amount of sample was sent into the sample feed tube. Afterwards, the delivery gas is sent to the sample feeding tube using the delivery gas supply mechanism.
A liquid sample supply device is used that sends out a sample using the pressure.

However, in conventional devices, the so-called drainage at the tip opening of the sample feeding tube is poor, resulting in a portion of the sample remaining attached to the tip opening, and as a result, the exact amount of sample that should be supplied is different. The reliability of sample supply is low due to
This also has the disadvantage that, for example, the analysis results become inaccurate. Even if the pressure of the delivery gas is increased, it is difficult to completely separate and supply all of the collected liquid sample from the sample feed tube.

On the other hand, when the device receiving the liquid sample is a delicate device such as the Karl Fischer water titration device as mentioned above, the pressure of the delivered gas may change instantaneously to the liquid level in the titration vessel. Errors in measurement may occur due to changes in the system pressure due to the action of titration, or entrainment of vapor within the titration vessel when the delivered gas passes over the liquid surface in the titration vessel. It was hot.

[Purpose of invention]

The present invention was developed based on the above-mentioned circumstances, and is highly reliable because it can completely supply the collected liquid sample. The purpose of the present invention is to provide a liquid sample supply device that does not give a liquid sample.

A specific object of the present invention is to provide a liquid sample supply device particularly suitable for use in a Karl Fischer automatic moisture titration device.

[Structure of the idea]

The feature of the present invention is that in a liquid sample supply device that supplies a predetermined amount of collected liquid sample by the gas pressure of a delivery gas, the device is arranged perpendicularly to the container to which the liquid sample is to be supplied. A mantle tube, a liquid sample feed tube extending into the mantle tube, and a tip tube part provided at the tip of the liquid sample feed tube and having an open end surface extending in the vertical direction and extending along a plane diagonally intersecting the central axis thereof. a delivery gas supply mechanism connected to the liquid sample feeding tube; and a gas vent hole formed in the mantle tube, the mantle tube having:
The buffer portion has an inner diameter a that is twice or more the outer diameter d of the tip tube portion and a height h that is five times or more the outer diameter d of the tip tube portion, and the gas vent hole is located in the tip tube portion. It is located at a point located above the opening end surface.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the present invention, as shown in FIG. 1, a mantle tube 1 having an inner diameter a is arranged vertically, and an end face cut along a plane obliquely intersecting the axis X of the mantle tube 1 is provided at the lower end. At the same time, a gas vent pipe 4 having a slightly smaller diameter is vertically connected to the top so as to communicate through a gas vent hole 3. A liquid sample feeding tube 5 is provided so as to pass through the peripheral wall of the outer tube 1, and a distal end tube portion 6 having an outer diameter d extending perpendicularly along the axis X of the outer tube 1 is provided at the tip thereof. An open end surface 7 is formed at the lower end, which is cut along a plane that obliquely intersects the axis X at a right angle α. Furthermore, the liquid sample feeding tube 5
is connected, for example, via a rotary valve 10, to a liquid sample source 20 and a delivery gas supply mechanism 30, which includes, for example, a nitrogen gas source. 8 is a container into which a liquid sample is to be supplied, specifically, for example, a titration container in a Karl Fischer moisture analyzer.

Here, the mantle tube 1 has an inner diameter a of 2d or more and a height h of 5d or more below the tip tube section 6, and has a gas pressure of the delivery gas ejected from the tip tube section 6. It has a buffer part B that constitutes a space for absorbing water. Further, the inner diameter a of the outer tube 1 is preferably 5 to 20 mm, the outer diameter d of the tip tube portion 6 is preferably 0.5 to 5 mm, more preferably 1 to 3 mm, and the height h of the buffer portion B in the outer tube 1 is: Preferably, it is 15 to 50 mm, and the angle α of the open end surface of the tip tube portion 6 with respect to the axis X is 20 to 70 degrees.

FIG. 2 shows an example of a rotary valve 10 connected to the liquid sample supply pipe 5 for automatically collecting a liquid sample, in which 11 is a sample introduction pipe, 12 is a sample discharge pipe, and 13 is a delivery pipe. gas introduction pipe,
Reference numeral 14 indicates a measuring tube section, and 15 indicates a measuring sample supply tube.
This rotary valve 10 automatically and repeatedly collects a predetermined amount of sample and supplies this sample by rotating the movable part 16. That is, during non-metering, the portion shown by the solid line in FIG. 2 is in a communicating state, and the delivery gas flows through the metering tube section 14. During measurement, the movable part 1
6 is rotated by 60 degrees, the broken line part in FIG.
The sample is supplied to the measuring tube section 14 and discharged from the sample discharge tube 12. Then, the movable part 16 rotates 60 degrees again to enter the non-metering state, and as a result, the sample collected in the measuring tube section 14 is measured by the pressure of the delivery gas supplied to the delivery gas introduction pipe 13. The sample is sent out to the sample supply tube 15, and the sample is supplied.

[Operation and Effect of the Invention] Since the liquid sample supply device of the present invention has the above-described configuration, a predetermined amount of the liquid sample collected from the liquid sample source 20 is absorbed by the delivery gas supplied from the delivery gas supply mechanism 30. Liquid sample feed tube 5 by pressure
is sent to the tip tube part 6 through the opening end surface 7, and is dripped under the action of gravity into the container 8. In the Karl Fischer moisture analyzer, the water in the sample liquid is Detected as size.

In the present invention, the tip tube part 6 is located within the mantle tube 1 and is surrounded, so that it is less susceptible to the influence of the outside world, and therefore the delivered gas is stabilized along the axis X direction of the mantle tube 1. In addition, gravity acts on the droplets on the opening end surface 7 in the same direction, and since the opening end surface 7 is formed obliquely and its lowest end is in the state of a point, the water drains easily. For this reason, the fed sample is completely separated from the tip tube portion 6 and dripped without remaining attached thereto.

Moreover, the outer tube 1 is formed with a buffer section B having an internal space large enough to absorb the gas pressure of the delivery gas ejected from the tip tube section 6, and further has a gas vent hole 3. Therefore, the instantaneous pressure of the delivered gas is buffered without being directly transmitted to the container receiving the sample, such as the reaction cell 8 in an analytical test, and as a result, measurement errors due to the gas pressure of the delivered gas are prevented. As a result, for example, moisture in a liquid sample can be measured with high reliability over a long period of time.

As described above, the present invention can accurately supply a predetermined amount of sample, and can also effectively eliminate the influence of the air flow or pressure of the delivery gas used to supply this sample. It can be suitably used in a Karl Fischer automatic moisture titration device for measuring trace amounts of moisture, which is one of the analysis methods that requires strict conditions in operations such as supply. By the way, the measurement accuracy of the Karl Fischer automatic moisture titration device constructed using the above-mentioned liquid sample supply device according to the present invention was extremely high with an error of approximately ±0.3 ppm, as shown in the following example. . That is, using an online Karl Fischer moisture analyzer in which the device of the present invention was connected to a Karl Fischer titration vessel, 10 ml of toluene was analyzed five times as a sample, and the moisture values were 11.1, 10.8, 11.1,
11.1, 11.3 (ppm), average is 11.1±0.3ppm
It was hot. On the other hand, the same toluene was used as a sample, and the same analysis was performed five times without using the device of the present invention, but using a moisture analyzer in which the gas vent tube and sample injection tube were each connected directly to the Karl Fischer titration vessel. As a result, the moisture values were 12.6, 14.1, 17.3,
15.4, 13.7 (ppm), and the average is 14.6±2.7ppm
It was hot.

One embodiment of the present invention has been described above, but
Various modifications can be made to the present invention. For example, the position of the gas vent hole 3 formed in the mantle tube 1 is as long as it is located above the opening end surface 7 of the tip tube section 6 so that the delivery gas ejected from the tip tube section 6 can be efficiently discharged to the outside world. There are no particular restrictions. Further, the shape, dimensions, etc. of the outer tube, liquid sample feeding tube, or tip tube can be selected as appropriate.

The device to which the liquid sample supply device of the present invention can be applied is not particularly limited, and can be applied to various cases where a predetermined amount of liquid sample must be repeatedly supplied, but is particularly applicable to Karl Fischer automatic water titration. It can be suitably used for devices. Furthermore, the liquid sample supply device of the present invention can automate the separation of liquid samples by using a rotary valve, etc. as in the example described above, and thereby the liquid sample can be repeatedly supplied. It is extremely convenient to perform, and especially when applied to an online Karl Fischer automatic water titration device, it is possible to improve analytical accuracy by about 10 times compared to conventional devices.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing an example of a liquid sample supply device of the present invention, and FIG. 2 is an explanatory view showing an example of a rotary valve. 1... Outer tube, 2... Opening, 3... Gas vent hole, 4... Gas vent tube, 5... Liquid sample feeding tube, 6
... Tip tube part, 7 ... Opening end surface, B ... Buffer part,
8... Container, 10... Rotary valve, 20...
...liquid sample source, 30...delivery gas supply mechanism.

Claims (1)

[Scope of Claim for Utility Model Registration] In a liquid sample supply device that supplies a predetermined amount of a collected liquid sample using the gas pressure of a delivery gas,
A mantle tube arranged perpendicularly to the container into which the liquid sample is to be supplied, a liquid sample feed tube extending into the mantle tube, and a tube extending in the vertical direction and provided at the tip of the liquid sample feed tube. The mantle tube includes a tip tube portion having an open end surface along a plane obliquely intersecting the axis, a delivery gas supply mechanism connected to the liquid sample supply tube, and a gas vent hole formed in the mantle tube. is below the tip tube section,
The buffer portion has an inner diameter a that is twice or more the outer diameter d of the tip tube portion and a height h that is five times or more the outer diameter d of the tip tube portion, and the gas vent hole is located in the tip tube portion. A liquid sample supply device characterized by being located above an opening end surface.