JP3824148B2 - Gas chromatograph - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas chromatograph.
[0002]
[Prior art]
In general, the gas chromatograph is configured with an oven that contains a column, and the oven is the majority of the entire structure. Normally, control devices for the gas system and the electrical system are arranged.
Although the oven wall and the front door are insulated, the temperature inside the oven can be as high as 500 degrees depending on the analysis. It can be dangerous. For this reason, there is also a gas chromatograph configured to forcibly air-cool the upper surface of the oven and the front door that the operator is likely to touch.
[0003]
FIG. 3 shows a schematic structure of such a conventional gas chromatograph. This figure shows a longitudinal section, and the left side of the figure is the front surface.
In the figure, 1 is a tank chamber of an oven surrounded by a heat insulating wall 11, and 3 is a front door that covers the front surface thereof. Reference numeral 2 denotes a sample introduction unit and a detector disposed on the oven upper surface 4, both of which are configured to have a compatible unit structure (hereinafter, the sample introduction unit and the detector are simply distinguished from each other without being distinguished from each other). Write down). A plurality of units 2 are appropriately arranged as required for analysis. The upper cover 41 covering the upper portion is provided with a small hole at a position corresponding to the sample injection port and the exhaust port of the unit 2, and enables sample injection from the outside and exhaust from the detector.
Reference numeral 5 denotes a motor that rotates a fan 51 for forcibly circulating the air in the tank chamber 1, and also serves to cool the external surface at the same time. That is, the motor 5 is a double-shaft type, and the front door 3 and the oven upper surface 4 are forcibly air-cooled by another fan 52 provided on the rear shaft as follows.
[0004]
The front door 3 is provided with a gap 33 between the heat insulating layer 32 on the inner side and the door surface 31. The gap 33 communicates with the outside air through a slit 34 provided at the lower part of the door surface 31, and the gap at the upper part of the door. 35, it communicates with a space 42 sandwiched between the oven upper surface 4 and the upper cover 41. The upper cover 41 is connected to an air intake duct 43 that surrounds the fan 52 on the back surface so as to be substantially airtight.
In such a structure, when the motor 5 rotates, the outside air is sucked in from the slit 34 due to the intake action of the fan 52, and the air reaching the rear fan 52 through the upper space 42 from the gap 33 inside the front door 3. A flow (indicated by an arrow in the figure) is generated, and the cooling effect thereby keeps the front and upper surfaces of the gas chromatograph at a relatively low temperature, preventing the risk of burns and the like due to contact.
[0005]
[Problems to be solved by the invention]
In the gas chromatograph having a structure in which the outer wall surface of the oven is forcibly air-cooled as described above, the unit 2 disposed on the upper surface 4 of the oven is exposed to an air flow (cooling air) for cooling, and the temperature is cooled. Influenced by wind. In particular, when a plurality of units 2 are arranged side by side, the way of receiving wind is different between each unit 2, so that each unit 2 is affected differently, resulting in temperature variations, and as a result, even when analyzing the same sample The problem is that there may be a difference in analysis results between each unit 2.
An object of this invention is to provide the gas chromatograph which eliminates such a problem.
[0006]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, in the gas chromatograph configured to forcibly air-cool the inside of the outer wall surface of the oven in which the sample introduction unit and the detector unit are disposed with cooling air, the gas chromatograph is close to the unit. A shielding plate facing the cooling air flow was provided. In addition, the shield plate has a structure that can be moved by screwing or fitting. This prevents the cooling air from directly hitting the units, thereby mitigating the influence, reducing the temperature difference between the units, and improving the data reproducibility between the units.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention is shown in FIG. This figure shows a plan view, that is, a state when the gas chromatograph is viewed from above, and is shown with the upper cover (41 in FIG. 3) removed for convenience of explanation.
In the figure, 2 (a, b, c) is a unit of three sample introduction units disposed on the upper surface 4 of the oven. In addition, although the case of the sample introduction part was illustrated here as the unit 2, the case of a detector is also the same.
7 is a control unit adjacent to the oven, and its control panel 71 is located on the front side of the apparatus along with the front door 3 of the oven. Reference numeral 8 denotes a back cover that covers various structures on the back of the apparatus.
[0008]
6 (a, b) is a shielding plate characterizing the present invention, and is installed close to the front and rear of the group 2 units 2. The cooling air flowing out from the upper part of the front door 3 flows as shown by the arrow in the figure, and the front shielding plate 6a facing this prevents the cooling air from directly hitting the unit 2a placed on the upstream side. On the other hand, the rear shielding plate 6b prevents cooling air from flowing around the downstream unit 2c. As a result, the influence of the cooling air received by each unit 2a, 2b, 2c becomes almost equal, and the temperature variation between them is reduced.
[0009]
FIG. 2 is an elevational view of the shielding plate 6 and shows, as an example, a state in which the front shielding plate 6a is viewed from the front, together with the unit 2a of the sample introduction portion arranged behind it (rear shielding). Since the plate 6b has the same shape, the distinction between a and b is not shown in the figure. The sample introduction unit 2 is provided with a sample injection port 21 at the top, and a rubber septum (not shown) is inserted immediately below. Since the septum needs to be kept as low as possible, septum cooling fins 22 are provided to cool the septum. The shielding plate 6 is made of a single metal plate such as stainless steel, and its size is determined as follows. That is, the width of the shielding plate 6 is set to be slightly larger than the width of the unit 2 so that the unit 2 can be sufficiently shielded from the cooling air, and the height is set below the septum cooling fins 22. This is because the cooling air is applied to the septum cooling fins 22 to ensure a sufficient cooling effect.
Since the shielding plate 6 has a simple structure composed of a single sheet metal as described above, the cost is low, and the mounting can be easily carried out by screwing or fitting, so that the number of units 2 can be increased or decreased. Can respond flexibly.
[0010]
The above is an example in which a shielding plate is provided before and after a group of units. However, if a shielding plate having a shape surrounding the group of units is used so as to cover not only the front and rear but also the side surfaces, the effect of cooling air The effect of protecting the unit from is even higher.
The present invention can also be applied to a gas chromatograph in which a unit such as a sample introduction unit is disposed on the front surface of the apparatus.
[0011]
【The invention's effect】
As described in detail above, the gas chromatograph according to the present invention is provided with the shielding plate that is close to the sample introduction unit and the detector unit and faces the flow of the cooling air, so that the cooling air directly hits the unit. This can prevent the temperature from being disturbed. In particular, when a plurality of units are arranged side by side, variations in characteristics due to the influence of cooling air between the units are reduced, and analysis reproducibility between the units is improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a partial structure in an embodiment of the present invention.
FIG. 3 is a diagram showing a schematic structure of a conventional gas chromatograph.
[Explanation of symbols]
2 ... Unit 3 ... Front door 4 ... Oven top surface 6 ... Shield plate 7 ... Control unit 8 ... Back cover

Claims (1)

In a gas chromatograph configured to forcibly air-cool the inside of the outer wall surface of the oven in which the sample introduction part and / or the detector are arranged with cooling air, the cooling air is placed close to the sample introduction part and / or the detector. A gas chromatograph characterized in that a shielding plate facing the flow is provided, and the shielding plate is screwed or fitted and can be moved .

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