JP2002014087A - Gas chromatograph oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cooling time for a gas chromatograph oven for performing a programmable temperature increase analysis. SOLUTION: An oven enclosure is composed of an inner wall material, where the channel of liquid for cooling is provided inside, and air or the like is circulated to the channel in cooling. More specifically, the inner wall material 10 is composed by sealing and compressing, sandwiching a spacer material 10b between two metal thin plates 10a, and a gap that is surrounded by the metal thin plate 10a and the spacer material 10b is set to the channel of liquid for cooling. A channel 13 is formed on the entire surface of the inner wall material 10, by folding for many times at both ends from one corner to its opposite angle, and a conduit 12 is provided at both the end parts of the channel. The inner wall material thus composed is folded into a square shape and both the ends are jointed, and a rear wall is mounted to compose the oven enclosure. When the oven is to be cooled, air is fed through the conduit 12, for cooling from the inside of the inner wall material. By using method concurrently with the conventional cooling means, cooling time is further reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas chromatograph oven, and more particularly to an oven suitable for use in a gas chromatograph for performing programmed temperature rise analysis.

[0002]

2. Description of the Related Art A gas chromatograph is provided with an oven for heating a column to a predetermined temperature for analysis. The program temperature rise analysis is a method of analyzing the temperature of the oven from a relatively low temperature near room temperature (near room temperature) to a high temperature of several hundred degrees while gradually increasing the temperature according to a predetermined program. In a programmed temperature analysis, it is important to control the temperature accurately in accordance with the program, but at the same time, after the analysis is completed, quickly set the oven at high temperature so that the next analysis can be started immediately. Cooling to near room temperature is required.

FIG. 3 is a schematic view showing a cooling mechanism in a conventional typical gas chromatograph oven. In the figure, an oven housing 1 is assembled in a box shape by a method such as welding using an inner wall material of a thin metal plate such as stainless steel as a main constituent material. 2 is a heat insulating material covering this housing,
It is indispensable to keep the inside of the oven at a predetermined temperature. Further, the outside of the heat insulating material is usually covered with an outer wall material that serves both protection of the heat insulating material and aesthetic purpose, but is omitted in this figure.

[0004] The fan 3 in the oven is driven by a motor (not shown) provided on the outside rear surface of the oven, and circulates the air in the oven to uniformly heat the inside of the oven. The intake port 4 and the exhaust port 5 provided on the rear wall 11 are normally closed by a door 6 when heating, but when cooling the oven, the door 6 is opened to take in cool outside air from the intake port 4. At the same time, hot air in the tank is discharged from the exhaust port 5. At this time, the outside air is taken in by the suction force of the fan 3, but an intake duct 41 is provided for effective suction, and the air is guided from the intake port 4 to a position immediately behind the fan 3 by a duct and then sucked into the tank. Have been. Although the door 6 may be provided separately for the intake port 4 and the exhaust port 5, this is due to the arrangement of the intake port 4 and the exhaust port 5, and is not an essential difference.

[0005] Usually, a door for taking in and out a column or the like is provided on the front surface (left side in the figure) of the oven housing 1, and a sample introduction part and a detector are provided on the upper part. Further, a heater for heating and an auxiliary structure for supporting the heater are provided inside the oven, but these are not shown in the drawing because they are not directly related to the present invention.

[0006]

With such a configuration, in order to cool the heated oven to near room temperature after the completion of the program temperature increase analysis, the power of the heater is turned off and the door 6 is opened to open the air inlet. The cool outside air is taken in from 4 and the hot air in the tank is discharged from the exhaust port 5. As a result, 40
Cooling can be performed from a high temperature of about 0 ° C. to near room temperature in 5 to 10 minutes. However, from the viewpoint of operating efficiency of the analyzer, this cooling time is useless, and it is desired to reduce the cooling time as much as possible. For this reason, conventionally, the intake duct 41 is provided to increase the intake and exhaust efficiency during cooling, and the heat capacity is reduced by using an extremely thin metal plate having a thickness of about 0.4 mm as the inner wall material 1. However, at present the cooling time is required to be further reduced. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a gas chromatograph oven that can further reduce the cooling time.

[0007]

According to the present invention, in order to solve the above-mentioned problems, an oven housing is constituted by using an inner wall member provided with a flow path of a cooling fluid inside a material itself. This allows the cooling speed to be increased and the cooling time to be shortened by allowing air or the like to flow through this flow path during cooling.

[0008]

FIG. 1 shows an embodiment of the present invention. FIG. 1A shows an expanded state of the inner wall material 10 constituting the oven housing, which is bent into a bracket shape at the position of a chain line, and a rear wall is attached thereto to form a housing. The inner wall member 10 is formed by sealingly pressing the two thin metal plates 10a having a thickness of 0.1 to 0.2 mm with the spacer member 10b interposed therebetween. FIG. 2B shows a part of a cross section of the inner wall material 10, and as shown, a gap surrounded by the thin metal plate 10a and the spacer material 10b is formed. This gap is used as a flow path 13 of the cooling fluid described below. Spacer material 10
b is an elongated metal plate having a thickness of about 0.5 to 3 mm, which is arranged so as to border the inner wall material 10, and furthermore, what is at both ends from one corner to its diagonal throughout the inside surrounded by the border. It is arranged so as to form a single flow path 13 that is folded again.
A hole is formed in one of the metal sheets 10a as a fluid inlet / outlet at both ends of the return channel, and a conduit 12 is attached to the hole by welding or the like.

By bending the inner wall member 10 having the above-described configuration into a square shape and joining both ends thereof, and attaching a rear wall, an oven housing which is substantially similar in appearance to the conventional one shown in FIG. 3 is formed. At the time of bending, in order to prevent the flow path from being crushed at the bent portion, it is preferable to bend with an appropriate radius. The back wall can be made of a material having the same structure as that of the inner wall material 10. However, as described above, the back wall has openings (intake and exhaust ports), and a fan, a motor, and other structures are attached. Therefore, care must be taken to avoid these and arrange the flow path of the cooling fluid. In the present embodiment, in order to avoid such annoyance, the rear wall is made of a simple sheet metal as in the related art.

In the oven according to the present invention, cooling from a high temperature is performed as follows. First, as in the conventional case, the power of the heater is turned off, and the outside air is sucked and the hot air is discharged through the air intake / exhaust port. At the same time, the inner wall material 10
The inside wall material 10 is cooled from the inside by injecting air into and exhausting from the other conduit. A separate air supply means such as a pump may be provided to supply the air.However, gas chromatographs are generally equipped with an air compressor as ancillary equipment. It is easiest to get a supply. In this way, the outside air is taken into the oven by the fan 3 and the inner wall material 1
By allowing the cooling air to flow through the air itself, the surface area of the structure of the oven in contact with the cooling air increases, and the cooling time is further reduced.

The flow path pattern in the inner wall material 10 is not limited to the folded shape described above, and various deformations can be considered. FIG. 2A
Shows a parallel multi-channel pattern as an example. That is, since a large number of parallel flow paths branching at one end and joining at the other end are arranged, and the flow resistance is smaller than that of the folded shape in FIG. 1, it is possible to increase the flow rate of the cooling fluid, Cooling efficiency is improved. Further, in this pattern, since there is no problem even if there is a lateral leakage between the parallel flow paths, there is no need to pay attention to the sealing performance of the joint except for the rim, and the manufacturing is easy. Although not particularly shown, various modifications such as a spiral type, a radial type, or a pattern combining these are also possible as the flow path pattern.

When a large number of thin plate-like spacer members 10b are combined and arranged to form the above-described flow path pattern, workability during manufacturing is poor. If a patterned spacer material is formed by punching from one sheet material, the productivity is improved. In order to further increase the productivity, a manufacturing method in which the flow path pattern is protruded to one side of the thin metal plate 10a by press working without using the spacer material 10b, and this and another flat plate are pressed together is also conceivable. . FIG. 2B illustrates a cross section of the inner wall material according to such a manufacturing method.

In the above, when a gas or liquid having higher thermal conductivity is used as the cooling fluid instead of the air sent into the inner wall material, the cooling effect can be further enhanced. When air is used as the cooling fluid, 2
Of the conduits 12, the conduit on the outlet side may be omitted, the exhaust port may be simply opened, and the cooled air may be directly discharged to the atmosphere to simplify the structure.

[0014]

As described in detail above, the present invention provides a fluid flow path inside the inner wall material itself, which is a structural material of the oven, and allows a cooling fluid such as air to flow through the flow path during cooling. As a result, the cooling of the oven is promoted, so that the cooling speed can be improved and the cooling time can be shortened by using the conventional oven cooling mechanism together. Further, as a secondary effect, since there is a gap inside the wall material, the weight of the oven can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a modification of the present invention.

FIG. 3 is a view showing the structure of a conventional gas chromatograph oven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oven housing 2 ... Heat insulation material 3 ... Fan 4 ... Inlet port 5 ... Exhaust port 6 ... Door 10 ... Inner wall material 10a ... Metal thin plate 10b ... Spacer material 11 ... Back wall 12 ... Conduit 13 ... Flow path

Claims (1)

[Claims] 1. An oven for accommodating a gas chromatography column in an inner space of a housing constituted by at least a heat insulating material and an inner wall material inside the housing, wherein the inner wall material is provided with a means for flowing a cooling fluid. An oven for gas chromatography, characterized by using wall materials.