JPH0524875Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a connection structure for reaction tubes. More specifically, the present invention relates to improvements in connection structures of reaction tubes in thermal analysis devices such as thermogravimetry devices (thermobalances), differential thermal analysis devices, and thermomechanical analysis devices.

(b) Conventional technology Among thermal analysis techniques, the method of continuously measuring the weight change of a sample while heating it at a constant rate is known as thermogravimetry (TG). Measuring devices (also known as thermobalances) are commonly used. In these thermogravimetric measuring devices, the sample is usually heated in a reaction tube made of quartz or ceramics. This is to seal the heating atmosphere. These reaction tubes are constructed so that they can be separated from the main body of the measuring device for sample exchange, and as shown in Figure 5, the connection structure of the reaction tubes is sealed using an O-ring. Are known. Although FIG. 5 shows an example of a hanging type thermogravimetric measuring device, the same applies to a top plate type device.

(c) Problems to be solved by the invention However, in order to ensure high sealing performance in such a structure, it is necessary to use an O-ring 3 having an inner diameter considerably smaller than the outer diameter of the reaction tube 2 to tighten the reaction tube. It is necessary to increase the attachment force, and considerable force is required when attaching and detaching the reaction tube, making it inconvenient to handle.
It is also unfavorable in terms of handling of reaction tubes made of quartz or ceramics, which have low impact resistance.

This invention was devised in view of these problems, and in particular aims to provide a connection structure for reaction tubes that is convenient to handle and can reduce the force required when attaching and detaching reaction tubes despite its high sealing performance. It is something.

(d) Means for solving the problem Thus, according to this invention, the end of the connecting tube to which the reaction tube of the thermal analyzer is connected is at least (a) an inner tube with an inner diameter smaller than the inner diameter of the reaction tube; (b) a fitting tube section with an inner diameter into which the reaction tube can be inserted; and (c) an outer tube section with an inner diameter larger than the outer diameter of the reaction tube. A reaction tube provided with a flange is inserted into the fitting tube section of the connecting tube and abuts the lower end of the inner tube section, and an O-ring is placed between the reaction tube and the outer tube section.
A cylindrical pressing means is attached to the reaction tube along the corner of the tube, and a cylindrical pressing means for applying pressure toward the inner tube by contacting the O-ring is installed within the space, and further, the cylindrical pressing means The reaction tube pressing member presses the cylindrical pressing means such that the reaction tube is pressed toward the inner tube portion and the reaction tube is inserted into the fitting tube portion of the connecting tube and abuts the lower end of the inner tube portion. A connection structure for the reaction tube attached to the reaction tube is provided through a first spring for pressing the flange and a second spring for inserting the reaction tube.

The most distinctive feature of this invention is that the O-ring is not embedded in a groove as in the conventional method, but is interposed between the inner wall of a specific stepped tube and the cylindrical pressing means. According to such a structure, even if an O-ring having a relatively weak clamping force to the reaction tube is used, the clamping force is significantly increased by the pressure of the cylindrical pressing means, and high sealing performance can be obtained.

The cylindrical pressing means described above can be made of various materials that have the strength to withstand the pressing force, but if it is made of a metal with good thermal conductivity, the O-ring will not be able to move efficiently by the pressing means when heating the reaction tube. This is a preferred embodiment because it is well cooled. Examples of such metals with good thermal conductivity include aluminum, copper, brass, and the like. Note that these cylindrical pressing means may further be provided with cooling fins for cooling the O-ring.

In addition, as the O-ring used in this invention,
A material made of heat-resistant rubber such as silicone rubber or fluorine rubber is suitable. However, its inner diameter may be slightly smaller than the outer diameter of the reaction tube, and it is sufficient to have a weak tightening force. Even if such an O-ring with a weak tightening force is used, the same sealing performance as using an O-ring with a strong tightening force can be obtained when the connection is completed.

(e) Action The force generated by the pressure of the reaction tube pressing member is the first
The cylindrical pressing means is pressed toward the inner tube part via the spring. At the same time, the reaction tube is inserted into the fitting tube section of the connecting tube via the second spring and brought into contact with the lower end of the inner tube section. As a result, the O-ring that fastens the reaction tube increases its fastening force and acts to provide high sealing performance. Therefore, O
- Even if a ring is used, a highly airtight connection is possible, and the workability of inserting and removing reaction tubes is improved.

(F) Embodiment FIG. 1 is an explanatory diagram showing an embodiment of the reaction tube connection structure of this invention.

In the figure, 1 is the end of the connecting tube to which the reaction tube in the thermogravimetric measuring device is connected; the inner tube section A has an inner diameter smaller than the inner diameter of the reaction tube, and the fitting tube section B has an inner diameter into which the reaction tube can be inserted. , and an outer tube portion C having an inner diameter larger than the outer diameter of the reaction tube, and is configured to allow a sample container suspended from the balance to pass through.

The reaction tube 2 made of quartz glass is inserted into the fitting tube section B, brought into contact with the lower end 10 of the inner tube section A, and fixed by the second spring 6 of the reaction tube press fitting 5. An O-ring 3 having an inner diameter slightly smaller than the outer diameter of the reaction tube 2 (for example, an interference margin of 0.5 to 1 mm) is installed in the cylindrical space between the reaction tube 2 and the outer tube portion C. It is fastened to the reaction tube 2.

A cylindrical pressing means 4 (made of stainless steel) having a flange is installed in the cylindrical space, and a first spring 7 applies pressure upward in the drawing to the O-ring 3. has been done. In the figure, 8 is a guide fitting of the pressing means 4, and 9 is a flange portion of the reaction tube with respect to the second spring 6.

In this structure, high sealing performance by the O-ring 3 is obtained by the pressing means 4.

The procedure for constructing this structure will be explained below with reference to FIG.

First, A in Fig. 2 shows the initial state of insertion into the end 1 of the connecting tube to which the reaction tube 2 is connected, and the reaction tube 2 is inserted into the fitting tube section B and comes into contact with the inner tube section A. This state is shown in Figure 2B. Here, the first spring 7 is positioned so that it does not come into contact with the cylindrical pressing means 4 and does not move the pressing means until at least the reaction tube 2 comes into contact with the O-ring 3. As the reaction tube 2 rises, the first spring 7 comes into contact with the pressing means 4, whereby the pressing means 4 rises by Δ and first contacts the O-ring 3. Up to this state, the only clamping force on the reaction tube 2 is that of the O-ring itself, so the reaction tube 2 is smoothly inserted into the fitting tube part B via the O-ring by pressing from below. be done. As it rises further, the pressing means 4 presses the O-ring 3 by the first spring 7, but since the reaction tube 2 is supported by the force of the second spring 6, the pressure causes the inner diameter of the O-ring 3 to Even if it narrows, it will rise smoothly and become the state shown in Figure 2 (b).

FIG. 2C shows a state in which upward pressure is applied to the reaction tube 2 by pushing up the pressing fitting 5, and upward pressure is applied to the O-ring by the cylindrical pressing means 4. In this state, the first
Since a pressure equivalent to contracting the spring 7 by ΔL is applied to the O-ring 3, the tightening force of the O-ring to the reaction tube 2 increases significantly, and
Since it is pressed upward, the reaction tube 2 and the end 1 of the connecting tube are completely sealed.

In addition, when removing the reaction tube 2 after the measurement is completed,
This operation can be performed in reverse. That is, by lowering the pressing means 4 from the sealed state shown in FIG. 2C (during which time the reaction tube remains stationary), the state shown in FIG. This is done by When lowering the reaction tube 2,
Since the pressure on the O-ring 3 is reduced or released, it can be carried out smoothly in the same manner as described above, and is extremely convenient in handling.

In addition, although stainless steel was used as the material for the pressing means 4, if a metal with good thermal conductivity is used instead, the effect of dissipating heat from the seal part and the O-ring will be significantly improved, and the measurement This is preferable because it prevents the O-ring from being adversely affected by temperature rise during the process. Further, it is preferable to provide heat dissipation means such as a large flange or fin on the pressing means 4 from the viewpoint of further heat dissipation. An embodiment with such a configuration is shown in FIGS. 3A and 3B. In the figure, 4a
4b shows a flanged cylindrical pressing means made of a metal with good thermal conductivity, and 4b shows a cylindrical pressing means with fins made of a metal with good thermal conductivity. Here, aluminum, copper, brass, etc. are suitable as the thermally conductive metal. When such a pressing means is used, its heat dissipation effect makes it possible to configure the heating section and the connecting section closer than before, and accordingly the length of the reaction tube can be shortened. .

Incidentally, FIG. 4 shows a connection structure of the present invention having the same configuration as FIG. 1 except that the pressing structure by the spring is different.

(G) Effects of the invention According to the connection structure of this invention, the force generated by the pressing of the reaction tube pressing member presses the cylindrical pressing means toward the inner tube portion via the first spring. At the same time, the reaction tube is inserted into the fitting tube section of the connecting tube via the second spring and brought into contact with the lower end of the inner tube section. Thereby, even if an O-ring with low tightening force is used, it is possible to obtain sealing performance that can maintain the high sealing performance required for a thermal analysis device. Therefore, the reaction tube can be attached and detached smoothly, and the risk of breakage of the reaction tube can be reduced, which is extremely advantageous in terms of handling.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the invention, FIGS. FIG. 5 is a diagram illustrating a conventional connection structure. 1...End of connecting tube, 2...Reaction tube, 3...O
-Ring, 4... Cylindrical pressing means, 5... Reaction tube pressing member, 6... Second spring, 7... First spring, 9... Flange portion, 4a... Cylindrical pressing means with flange, 4b ... Cylindrical pressing means with fins.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. The end of the connecting tube to which the reaction tube of the thermal analyzer is connected is at least (a) an inner tube portion with an inner diameter smaller than the inner diameter of the reaction tube; (b) a portion into which the reaction tube is inserted; The above reaction tube is composed of a stepped tube, which has a fitting tube section with an inner diameter that can be fitted into it, and (c) an outer tube section with an inner diameter larger than the outer diameter of the reaction tube, in this order, and a flange is provided on the outer periphery. It is inserted into the fitting tube part of the connecting tube and comes into contact with the lower end of the inner tube part, and the O-ring is tightened to the reaction tube along the corner between the reaction tube and the outer tube part. A cylindrical pressing means that contacts the O-ring and applies pressure in the direction of the inner tube is installed within the above-mentioned space, and the cylindrical pressing means is further pressed in the direction of the inner tube and presses against the reaction tube. The reaction tube pressing member presses the first spring for pressing the cylindrical pressing means and the flange so that the reaction tube is inserted into the fitting tube portion of the connecting tube and abuts the lower end of the inner tube portion. and a second spring for inserting the reaction tube,
Connection structure of the reaction tube attached to the reaction tube. 2. The structure according to claim 1, wherein the thermal analysis device is a thermogravimetry device. 3. The structure according to claim 1, in which the cylindrical pressing means is made of a metal with good thermal conductivity. 4. The structure according to claim 1, in which the cylindrical pressing means has a heat radiation means.