JP3097177B2 - Surface area measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously measuring the surface area of a powder or a porous body by applying a gas adsorption method.

[0002]

2. Description of the Related Art As an apparatus for continuously measuring the surface area of a large number of powders and porous samples, an apparatus based on a flow method among gas adsorption methods is already known. Conventional devices of this type are roughly classified into the following two types. One is a structure in which a large number (up to about 12) of sample cells can be attached, and these are attached first by hand, so that two sample cells are formed as a set, and pretreatment (degassing treatment) and This is a method in which measurement is repeated repeatedly.

The other is provided with a single port for both preprocessing and measurement, and a robot for attaching and detaching a sample cell to and from this port. In this method, about 20 samples are continuously measured.

[0004]

Among the conventional surface area measuring devices based on the flow method having the continuous measuring function, the former method uses the number of ports for mounting sample cells that can be continuously measured at one time. As a rule, the maximum is about 12 at the maximum, and it is difficult to apply to online. Further, in the latter method, since the pretreatment and the measurement are performed in series for each sample, there is a problem that the time required for the measurement is long and the processing ability is lacking.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a surface area measuring apparatus which can measure a large number of samples in a relatively short time and is suitable for online operation.

[0006]

A configuration for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. A surface area measuring apparatus according to the present invention includes a sample cell for storing a sample to be measured. And a turntable 1 having a plurality of support portions 1a for detachably supporting the turntable 9 and rotating in a step-like manner, and a support arranged at a specific position with respect to the turntable 1 and arriving at the position F. At least one measurement piping system 2 that communicates with the sample cell 9 supported by the section 1a and measures the amount of gas adsorbed by the sample therein, and a plurality excluding those that communicate with the measurement piping system 2 of the turntable 1. And a cooling means (Dewar bottle) 4 for cooling the sample cell 9 communicating with the measurement piping system 2 for communicating with the sample cells 9 and 9 for degassing the inside thereof. And turntable 1 A handling device (robot) 5 which is disposed in a predetermined positional relationship with respect to the supporting portion 1a which arrives at the position A and which attaches and detaches the sample cell 9; and a control portion 6 which controls each portion. The unit 6 is characterized in that it is configured to control each unit so as to continuously perform attachment / detachment of the sample cell 9, pretreatment, and adsorption amount measurement operation in synchronization with the step-like rotation of the turntable 1.

[0007]

The present invention considers that the time required for the degassing process, which is the pretreatment in this type of measurement, is generally longer than the time required for the measurement, and a plurality of support portions are provided on the turntable that rotates in a step shape. By providing a sample cell supported by a support part arriving at a specific position to the measurement piping system, and by communicating other pluralities to the pretreatment piping system,
It is possible to take a longer pre-processing time than the measurement time.

That is, based on the relationship between the measurement time of the sample and the pre-processing time, the number of the bearings is determined, for example, according to the ratio of these required times, and the turntable is determined by setting the measurement time of one sample as one cycle. The surface area of a large number of samples can be measured in a relatively short time by controlling each part so that pre-processing, measurement, removal of sample cells after measurement, and installation of new sample cells are repeated while rotating the Becomes

[0009]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention, and FIG. 2 is a perspective view showing a specific configuration example. The measurement principle is based on the flow method among normal gas adsorption methods, and detailed explanation is omitted.However, basically, a mixed gas of nitrogen gas, which is an adsorption gas, and helium gas, which is a non-adsorption gas, is used as a sample. A method for obtaining the surface area of a sample by measuring the thermal conductivity of a mixed gas upstream and downstream of the sample and measuring the physical adsorption of nitrogen gas by the sample contained in the sample cell. It is.

In this embodiment, the turntable 1
Is divided into six equal parts and the cell support 1
a is provided. The turntable 1 is driven by an actuator (not shown) such as a motor to support the cell support 1a.
..Stepwise rotation is provided at the arrangement pitch of 1a. This stepwise rotation is controlled by a timing signal supplied from a control unit 6 mainly composed of a CPU.

A non-rotatable manifold 7 is disposed on the upper surface of the turntable 1 in close contact therewith. The manifold 7 is provided with one measurement piping system 2 based on the above-described measurement principle and a pretreatment piping system 3 through which a purge gas for degassing is flown at positions A to F equally divided into six. Have been. The measurement piping system 2 has a cold trap 10 for removing moisture and the like contained in the mixed gas.
And a TCD 11 for measuring the thermal conductivity of the gas upstream and downstream of the sample cell to be measured, and this measurement piping system 2 is connected to a position F of the manifold 7. The output of the TCD 11 is taken into the control unit 6 via the amplifier 8.

The pretreatment piping system 3 is provided with the remaining A
-E are connected in parallel, and communicate with the inlet and outlet of the purge gas. In addition, a flow meter 20 for measuring the flow rate of the purge gas is connected to the pretreatment piping system 3. Each cell support portion 1a of the turntable 1 is constituted by a groove provided in the upper part of the sample cell 9 and into which a block-shaped mounting portion 9a can be inserted. A communicating through-hole is formed, and a seal member such as an "O" ring is provided on the sample cell side of the through-hole, so that the mounted sample cell 9 and each piping system are sealed in an airtight manner. It has a structure that allows communication.

Below the position F where the measurement piping system 2 is connected, a dewar bottle 4 for cooling the sample cell 9 arriving at this position to eliminate chemical adsorption and exclusively perform physical adsorption. It is arranged. This dewar 4
, Which stores a refrigerant such as liquid nitrogen, is mounted on the vertical mechanism 13 so as not to hinder the rotation of the turntable 1. The vertical mechanism 13 is driven by a signal from a driver 14 based on a command from the control unit 6.

A robot 5 for attaching and detaching the sample cell 9 to and from the turntable 1 is provided corresponding to the position A of the manifold 7, and a sample before measurement is provided on both sides of the robot 5. A conveyor 16 for transporting the accommodated sample cells 9... 9 and a conveyor 17 for transporting the sample cells 9.
Among the remaining positions B to E, a heater 18 having a substantially U-shaped cross section for heating the sample cells 9 is disposed below BD. The heater 18 has a temperature controller 19
Is controlled so as to heat each sample cell 9.

Next, the operation of each unit by the control unit 6 will be described. The turntable 1 is driven to rotate by one step from A to F while the dewar 4 is lowered.
At position A, sample cell 9 after measurement at position F
Is removed from the support 1a of the turntable 1 by the robot 5 and placed on the conveyor 17, and a sample cell 9 containing an unmeasured sample on the conveyor 16 is mounted on the support 1a.

After the replacement of the sample cell 9 is completed, the dewar 4 rises and the sample cell 9 newly arrived at the position F is obtained.
Is cooled, and adsorption of nitrogen gas on the sample surface starts. In this state, if it is determined that the adsorption equilibrium has been reached while monitoring the signal of the TCD 11 by the control unit 6, the Dewar bottle 4 descends, and the sample cell 9 rises to a temperature near room temperature. At this time, the nitrogen gas adsorbed on the sample surface is desorbed, and the TCD 11 measures the desorption amount. The measurement result of the desorption amount is converted into the surface area of the sample in the control unit 6.

When this measurement is completed, the turntable 1
Is given a step rotation, and the position A is
In the above, the sample cell 9 after measurement is replaced with a sample cell 9 that has not been measured. During this time, in a state where the sample cells 9... At the positions B to E are heated by the heater 18, a purge gas is flowed into the inside thereof, and a degassing process of an unmeasured sample is performed. Therefore, the degassing of the sample requires at least three times as long as the measurement time for one sample and the time for attaching and detaching the sample to and from the turntable 1, and sufficient degassing is performed before the measurement. .

By repeating the above operation, the surface area of a large number of samples is continuously and fully automatically performed, and the degassing process is performed in a short time without becoming a bottleneck. Here, at the position E, the heated and degassed sample cell 9 is allowed to cool naturally to a temperature close to room temperature to prevent the heated sample cell 9 from being inserted into the dewar bottle 4. Continuous measurement reduces the internal refrigerant. This decrease in refrigerant can be dealt with by adding a conventionally used automatic supply mechanism.

In the embodiment shown in FIG. 2, the sample cells 9
3 is radially supported toward the center of the turntable 1. In addition to this supporting method, for example, FIG. 3A is a perspective view of a main part, and FIG. 3B is a plan view of a piping diagram. Thus, a supporting method in which the sample cells 9 are rotated by 90 ° can be adopted. In this case, there is an advantage that the opening width of the heater 18 can be small and the heating efficiency is improved. However, if the dimensions of the turntable 1 are the same,
Here, there is a disadvantage that the number of cells that can be mounted is reduced as compared with that of FIG.

As a pretreatment, a method of performing vacuuming while heating or a method of simply performing vacuuming without heating can be adopted instead of a method of heating while flowing a purge gas as a pretreatment. Further, the present invention can be applied to a surface area measuring device based on the volume method of the gas adsorption method in addition to the flow method among the gas adsorption methods. In the volumetric method, basically, a sample cell having a known volume and an expansion chamber having a constant internal volume are partitioned by an on-off valve, and after the on-off valve is closed, the gas pressure in the expansion chamber is made constant. In this measurement method, the pressure at the time when the on-off valve is opened is detected as the amount of gas adsorbed by the sample as compared with the pressure according to the Boyle-Charles law. Other than that, the pre-processing and the like are the same, and the present invention can be similarly applied.

[0021]

As described above, according to the present invention, a turntable on which a plurality of sample cells can be mounted is rotated in a step-like manner, and a measurement pipe system is communicated with a sample cell that has reached a specific position. In addition, a piping device for pretreatment is connected to the other plurality of sample cells, and a handling device that is attached to and detached from the sample cell turntable in the vicinity of the turntable is provided. Synchronous control of sample cell attachment / detachment, degassing and measurement operation enables continuous and fully automatic measurement of surface area of many samples, and online surface area measurement It is possible to fully cope with.

Further, since the measurement and the pretreatment (degassing) are performed in parallel, the time efficiency of the measurement is improved, and there is no need to remove the sample cell from the pretreatment part and transfer to the measurement part. However, it does not come into contact with the outside air, and the reliability of the measurement is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing a specific configuration thereof.

FIG. 3 is a perspective view (A) of a main part of another embodiment of the present invention,
Piping diagram shown in plan view

[Explanation of symbols]

 1 ··· Turntable 1a · · · 1a · · · Cell support 2 · · · Measurement piping system 3 · · · Pretreatment piping system 4 · · · Dewar bottle 5 · · · Robot 6 · Control unit 7 Manifold 9 Sample cell 9a Mounting unit 10 Cold trap 11 TCD 13 Vertical mechanism 14 Driver 16, 17 ··· Conveyor 18 ··· Heater 19 ··· Temperature controller

Claims (1)

(57) [Claims] 1. A turntable which has a plurality of supporting portions for detachably supporting a sample cell containing a sample to be measured and which rotates in a step-like manner, and which is arranged in a specific positional relationship with respect to the turntable. And at least one measurement piping system for measuring the amount of gas adsorbed by the sample inside the sample cell supported by the support part arriving at the position, and communicating with the measurement piping system of the turntable. A pre-treatment piping system for communicating with a plurality of sample cells except for those that perform degassing therein, cooling means for cooling the sample cells communicating with the measurement piping system, and the turntable Is disposed in a predetermined positional relationship with respect to, has a handling device that attaches and detaches the sample cell to and from the bearing that has arrived at that position, and a control unit that controls each unit,
The control unit is a surface area measuring device configured to control each unit in order to continuously perform attachment / detachment of a sample cell, pretreatment, and an adsorption amount measurement operation in synchronization with the step-like rotation of the turntable.