JPH0438280Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to an apparatus for measuring the surface area of powders, granules or solids (hereinafter referred to as solids), and in particular to an automatic supply device for liquefied gas for cooling samples that is suitable for use in a solid surface area measuring device that automatically measures the surface area of solids using a gas chromatograph.

Conventional technology Conventionally, a concentration measurement method in a continuous flow system has been put into practical use as a method for measuring the surface area of a solid. This method uses a mixture of gas and inert gas and tracks its concentration changes using gas chromatography.The final calculation is performed using the isothermal equation for an infinite BET adsorption layer.

Next, a concentration surface area measurement method (gas chromatography method) in a continuous flow system will be briefly explained.

A first valve that adjusts the dilution gas pressure adjusts the dilution gas to a predetermined flow rate. Next, the adsorbed gas is adjusted to a constant pressure using a second valve that adjusts the adsorbed gas pressure, and P/Po is adjusted using a needle valve.
P/Po is usually set to three values in the range of 0.1 to 0.3.

The adsorbed gas adjusted by the first and second valves and the needle valve is mixed with the diluent by opening the stop valve, and is sent into the cold trap. Here, water and impurities in the diluent and adsorbent are removed and passed through the standard side of the thermal conductivity detector.

The mixed gas that has passed through the standard side passes through the sample in the sample tube, passes through the detection side of the thermal conductivity detector, and is discharged to the outside.

Now, if the temperature of the sample is much higher than the boiling point temperature of the adsorbed gas, the entire amount of the adsorbed gas passes through the detection side without being adsorbed by the sample. Therefore,
The gas composition passing through the standard side and the gas composition passing through the detection side are exactly the same, and the signal from the detector does not change.

Next, when the sample is cooled to the boiling point of the adsorbed gas, the adsorbed gas is adsorbed on the surface of the sample, the gas composition ratio passing through the standard side and the detection side changes, and a signal is generated according to the amount of change. However, when adsorption equilibrium is eventually reached, the signal from the detector becomes stable at the position before cooling.

If cooling of the sample is stopped after reaching adsorption equilibrium, the adsorbed gas adsorbed to the sample will be blown to the detection side by desorption and the mixed gas. At this time, a concentration change occurs again on the standard side and the detection side, and a signal opposite to the previous one is generated accordingly.

The magnitude of this signal is the amount of adsorbed gas at a certain value of partial pressure ratio P/Po.This operation is repeated at three points at each partial pressure ratio P/Po, the amount of adsorbed gas is measured, and the amount of adsorbed gas is calculated using the BET formula. We are looking for the surface area. He is usually used as a diluent for the adsorbed gas, and N2 is used as the adsorbed gas. Therefore, liquid nitrogen (ligN2) will be used as a coolant.

Problems that the invention aims to solve When cooling a sample to the boiling point of the adsorbed gas,
This is done by immersing the sample tube containing the sample into a cooling liquefied gas container containing liquid nitrogen, etc. However, as the cooling liquefied gas is left in the air, it evaporates and takes a long time. The amount decreases over time. Therefore, it is necessary to replenish the decreased amount, but conventionally, the amount of cooling liquefied gas has been manually monitored and the required amount has been replenished as necessary.

However, since it is an artificial method, it is not only troublesome, but also has the drawback of causing unforeseen errors.

The present invention was made in order to eliminate the above-mentioned drawbacks inherent in the conventional technology, and therefore, the purpose of the present invention is to automate all the above-mentioned human operations to prevent the occurrence of unexpected mistakes. It is an object of the present invention to provide a novel automatic supply device for a liquefied gas for cooling a sample, which is capable of removing the liquefied gas beforehand and automatically replenishing a required amount of liquefied gas to a cooling liquefied gas container as required.

Means for Solving the Problems In order to achieve the above object, an automatic sample cooling liquefied gas supply device according to the present invention is installed on a rotary turntable of a fully automatic surface area measuring device that measures the surface area of a solid. A device for supplying liquefied gas to freely disposed liquefied gas containers for sample cooling, the device comprising: a rotating shaft having a first hollow portion in an upper portion that is fixed to the turntable and rotates together with the turntable; a fixed shaft having a second hollow part communicating with and sealingly coupled to the first hollow part of the rotating shaft; a liquefied gas suction conduit provided on the fixed shaft and communicating with the second hollow part; provided on the shaft and said first
a liquefied gas supply conduit that communicates with the hollow part and is disposed such that its outlet end always faces the upper part of the liquefied gas container for cooling the sample; and a liquefied gas supply source connected to the liquefied gas suction conduit. and
Furthermore, a detector for detecting the amount of liquefied gas is provided in the sample cooling liquefied gas container, and a solenoid valve operated by a detection signal of the detector is provided between the liquefied gas suction conduit and the liquefied gas supply source. provided and configured.

Embodiment Next, a preferred embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a partially omitted schematic perspective view of the main parts of a solid surface area measuring apparatus including the present invention, and FIG. 2 is a sectional view of the main parts showing an embodiment of the present invention.

Referring to FIGS. 1 and 2, a device main body 100
A turntable 10 is provided rotatably around a rotating shaft 20A by a drive source 30. On the turntable 10, an electric furnace container 11 for baking out the sample, a liquefied gas container 12 for cooling containing liquefied gas (for example, liquid nitrogen) for cooling the sample, and a water container 13 for desorption are arranged at equal intervals, respectively. It is mounted so as to be movable up and down via rods 11b, 12b and 13b.

A fixed shaft 20B is connected to the upper part of the rotating shaft 20A by a sealing part 34, and around the fixed shaft 20B, eight sample tubes 19 corresponding to, for example, eight samples are connected to the conduits 21 to 24. via container 11,1
They are each fixed radially with the same spacing as the spacings 2 and 13. Only one sample tube 19 is shown in FIG. 2, and the others are omitted.

On the upper part of the apparatus main body 100, gas passage switching sockets 15, 17 for baking out or gas passage switching sockets 16, 18 for suction and desorption are connected by the same drive motor 37 via two connecting gears 35, 36, respectively. are arranged to operate simultaneously.

In the above configuration, the turntable 10 rotates in the direction of the arrow, and the container 11 is rotated as needed.
- 13 move up and down to accommodate or open the sample tube 19, thereby processing a plurality of samples simultaneously, and baking out the samples, gas adsorption, and desorption are automated and continuously executed.

The cooling liquefied gas container (for adsorption) 12 is filled with liquefied gas such as liquid nitrogen, and is provided with a detector 31 that detects the amount of the liquefied gas. When liquid nitrogen is used as the liquefied gas, a temperature sensor of about -198° C. is used as the detector 31. Furthermore, as seen in FIG. 2, a liquefied gas suction conduit 32 is formed in the fixed shaft 20B formed of a cylindrical body having a hollow portion 20B'. Furthermore, the fixed shaft 2 is secured by the O-ring seal 40.
A hollow part 20A' that communicates with the hollow part 20B' is formed in the upper part of the rotating shaft 20A that is rotatably connected to the rotary shaft 20A, and a liquefied gas supply conduit 33 that communicates with the hollow part 20A' is formed to protrude. ing. The outlet 33a of the conduit 33 is opposed to the inlet of the liquefied gas container 12. In addition, 27 indicates a cooling liquefied gas steering pin (liquefied gas supply source),
The wafer bin 27 is connected to the liquefied gas suction conduit 32 via a supply pipe 28 and a solenoid valve 41.

Next, the operation will be explained. Turntable 1
0, since the liquefied gas container 12 and the liquefied gas supply conduit 33 are fixed to the rotating shaft 20A, the rotating shaft 20
A rotates with A, and they always maintain the state shown in FIG. Now, when the cooling liquefied gas in the container 12 decreases and the detector 31 moves away from the surface of the liquefied gas, the temperature rises and the detector 31 operates, and the solenoid valve 41 is energized by the detection signal. The solenoid valve 41 is opened. As a result, the supply pipe 28, the solenoid valve 41, the conduit 32, the hollow part 20B', the hollow part 20
Liquefied gas is supplied to the container 12 via the channel formed by A' and the conduit 33. container 12
When the liquefied gas in the container reaches a predetermined value, the detector 31 stops operating, the solenoid valve 41 is deenergized, and the flow path is cut off, so that the supply of liquid gas to the container 12 is stopped. will be stopped. The above operations are automatically repeated, and the container 12 is always filled with the desired liquefied gas.

Effects of the invention The present invention is constructed and operates as described above. According to the invention, the liquefied gas container is automatically filled with the required amount of liquefied gas at all times, so that continuous automatic processing operation is possible. Nevertheless, the adsorption effect of the adsorbed gas on the sample is performed well and accurately, and the effect of realizing rapid and reliable measurement of the solid surface area is obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a solid surface area measuring device to which the present invention is applied, and FIG. 2 is a schematic sectional view showing an embodiment of the present invention. 10... Turntable, 11... Electric furnace container for baking out, 12... Liquefied gas container for cooling (for adsorption), 13... Water container for desorption, 20A... Rotating shaft,
20B...Fixed shaft, 27...Liquefied gas duplex (liquefied gas supply source), 28...Supply pipe, 30...
... Turntable drive source, 31 ... Liquefied gas amount detector, 32 ... Liquefied gas suction conduit, 33 ... Liquefied gas supply pipe, 34 ... Fixed shaft, rotating shaft seal section, 40 ... O-ring seal, 41 ……solenoid valve.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A device for supplying liquefied gas to a liquefied gas container for cooling a sample that is vertically movable on a rotary turntable of a fully automatic surface area measuring device that measures the surface area of a solid. a rotating shaft that is fixed to the turntable and rotates together with the turntable and has a first hollow section in its upper part;
a fixed shaft having a hollow portion; a liquefied gas suction conduit provided on the fixed shaft and communicating with the second hollow portion; and an outlet tip portion of the fixed shaft provided on the rotating shaft and communicating with the first hollow portion. a liquefied gas supply conduit arranged so as to always face the upper part of the liquefied gas container for sample cooling, and a liquefied gas supply source connected to the liquefied gas suction conduit. Automatic supply device for liquefied gas. (2) A detector for detecting the amount of liquefied gas is provided in the sample cooling liquefied gas container, and a solenoid valve is provided between the liquefied gas suction conduit and the liquefied gas supply source and is operated by a detection signal from the detector. Scope of Claim for Utility Model Registration No. (1), which is further characterized in that
An automatic supply device for liquefied gas for sample cooling as described in 2.