VACUUM DOUBLE STRUCTURE AND HEAT TREAT FURNACE

Abstract

A vacuum double structure includes: a tubular and metal inner wall member; a tubular and metal outer wall member in which the inner wall member is accommodated; and a sealing member provided between a facing surface of the inner wall member and a facing surface of the outer wall member. The sealing member includes an annular spacer, a first annular packing material, and a second annular packing material. The annular spacer is provided between the facing surface of the inner wall member and the facing surface of the outer wall member.

Claims

1. A vacuum double structure comprising: a tubular and metal inner wall member; a tubular and metal outer wall member in which the inner wall member is accommodated; and a sealing member provided between a facing surface of the inner wall member and a facing surface of the outer wall member, wherein the sealing member includes an annular spacer, a first annular packing material, and a second annular packing material; the annular spacer is provided between the facing surface of the inner wall member and the facing surface of the outer wall member; the first annular packing material is accommodated in a first groove formed on a first opposed surface of the spacer with respect to the facing surface of the inner wall member and abuts with the facing surface of the inner wall member; the second annular packing material is accommodated in a second groove formed on a second opposed surface of the spacer with respect to the facing surface of the outer wall member and abuts with the facing surface of the outer wall member; and the sealing member maintains a space between the inner wall member and the outer wall member in a vacuum state.

2. The vacuum double structure according to claim 1, wherein: the spacer is a member made of resin and having elasticity; and the spacer is supported by a metal belt-shaped ring provided on an inner peripheral surface of the spacer and a metal belt-shaped ring provided on an outer peripheral surface of the spacer.

3. A heat treat furnace comprising: a first vacuum double structure according to claim 1; and a second vacuum double structure according to claim 1, wherein the heat treat furnace has a structure in which a flange portion of an inner wall member of the first vacuum double structure and a flange portion of an inner wall member of the second vacuum double structure are placed to face each other via a third annular packing material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

[0013] FIG. 1 is a perspective sectional view of a vacuum double structure according to a first embodiment;

[0014] FIG. 2 is a plan view of a spacer 32 in the vacuum double structure according to the first embodiment;

[0015] FIG. 3 is a sectional view of a heat treat furnace to which the vacuum double structure according to the first embodiment is applied; and

[0016] FIG. 4 is a partial sectional view of a vacuum double structure according to a second embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0017] The following describes concrete embodiments to which the present disclosure is applied with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Further, the following description and drawings are simplified appropriately for clarification of the description.

[0018] (First Embodiment) First, with reference to FIG. 1, the following describes a vacuum double structure according to the first embodiment. FIG. 1 is a perspective sectional view of the vacuum double structure according to the first embodiment. As illustrated in FIG. 1, the vacuum double structure 1 according to the present embodiment includes an inner wall member 10, an outer wall member 20, and a sealing member 30, and can be applied to a heat treat furnace, for example.

[0019] As illustrated in FIG. 1, the inner wall member 10 is a tubular member made of metal such as stainless steel (that is, a metal member). One end of the inner wall member 10 is a closed end, and the other end thereof is an open end. A flange portion 11 projecting outwardly is provided in the open end of the inner wall member 10.

[0020] Similarly to the inner wall member 10, the outer wall member 20 is also a tubular member made of metal such as stainless steel (that is, a metal member). One end of the outer wall member 20 is a closed end, and the other end thereof is an open end. A flange portion 21 projecting inwardly is provided in the open end of the outer wall member 20. The inner wall member 10 is inserted from an open end of the outer wall member 20, and the vacuum double structure 1 has a bottomed double tubular structure. An exhaust port 22 communicating with a vacuum pump is formed on the outer wall member 20 and can evacuate a space between the inner wall member 10 and the outer wall member 20.

[0021] The sealing member 30 is a member having an annular shape in a plan view and fitted by insertion between respective facing surfaces of the flange portion 11 of the inner wall member 10 and the flange portion 21 of the outer wall member 20. By the sealing member 30, the space between the inner wall member 10 and the outer wall member 20 can be maintained in a vacuum state. Note that the inner wall member 10 and the outer wall member 20 may have open ends at both ends so that respective sealing members 30 are provided at the both ends.

[0022] The sealing member 30 includes two O-rings 31a, 31b and a spacer 32. Here, FIG. 2 is a plan view of the spacer 32 in the vacuum double structure according to the first embodiment. As illustrated in FIGS. 1, 2, the spacer 32 has a rectangular section and an annular shape in a plan view, and is made of a material (e.g., resin, ceramic, or the like) more excellent in heat insulating properties than metal. The material should be used selectively for different purposes as appropriate. More specifically, the spacer 32 is made of fluororesin, and the like, similarly to the O-rings 31a, 31b, for example.

[0023] As illustrated in FIGS. 1, 2, an opposed surface of the spacer 32 with respect to the facing surface of the flange portion 11 of the inner wall member 10 has a groove (a first groove) 32a in which the O-ring 31a is accommodated. In the meantime, as illustrated in FIG. 1, an opposed surface of the spacer 32 with respect to the facing surface of the flange portion 21 of the outer wall member 20 has a groove (a second groove) 32b in which the O-ring 31b is accommodated.

[0024] Since the grooves 32a, 32b are formed in the spacer 32, it is not necessary to form grooves to accommodate the O-rings 31a, 31b therein on respective facing surfaces of the flange portion 11 of the inner wall member 10 and the flange portion 21 of the outer wall member 20, and thus, the vacuum double structure 1 can be easily manufactured. Note that, in an example of FIG. 1, sectional shapes of the grooves 32a, 32b are a rectangular shape, but are not limited in particular. For example, the sectional shapes of the grooves 32a, 32b may be a triangular shape, or other polygonal shapes, or may be a semicircular shape, a semi-elliptical shape, or the like shape.

[0025] The O-ring (a first O-ring) 31a is accommodated in the groove 32a of the spacer 32, and abuts with the facing surface of the flange portion 11 of the inner wall member 10. The O-ring (a second O-ring) 31b is accommodated in the groove 32b of the spacer 32, and abuts with the facing surface of the flange portion 21 of the outer wall member 20.

[0026] As such, the O-rings 31a, 31b abut with in the grooves 32a, 32b of the spacer 32, respectively, and the O-rings 31a, 31b abut with the flange portion 11 of the inner wall member 10 and the flange portion 21 of the outer wall member 20, respectively. Hereby, the space between the flange portion 11 of the inner wall member 10 and the flange portion 21 of the outer wall member 20 is sealed.

[0027] In the vacuum double structure according to the present embodiment, by providing the spacer 32 between respective facing surfaces of the inner wall member 10 and the outer wall member 20, it is possible to freely enlarge the distance therebetween, without enlarging the O-rings in diameter.

[0028] Further, since the O-ring 31a having a small diameter and accommodated in the groove 32a of the spacer 32 abuts with the flange portion 11 of the inner wall member 10, it is possible to restrain promotion of heat transfer due to an increase in a contact area between the O-ring 31a crushed by vacuum with the inner wall member 10.

[0029] Similarly, since the O-ring 31b having a small diameter and accommodated in the groove 32b of the spacer 32 abuts with the flange portion 21 of the outer wall member 20, it is possible to restrain promotion of heat transfer due to an increase in a contact area between the O-ring 31b crushed by vacuum with the outer wall member 20. Accordingly, with the vacuum double structure according to the present embodiment, it is possible to improve heat insulating properties.

[0030] FIG. 3 is a sectional view of a heat treat furnace to which the vacuum double structure according to the first embodiment is applied. The heat treat furnace has such a structure that respective flange portions 11 of respective inner wall members 10 of a vacuum double structure 1a according to the first embodiment and a vacuum double structure 1b according to the first embodiment are placed to face each other via a packing material 40. The heat treat furnace is suitably used for a low temperature purpose of around 200 C., for example. A heat treatment object (not shown) is accommodated inside the inner wall members 10. Thus, with the use of the vacuum double structure according to the first embodiment, it is possible to provide a heat treat furnace excellent in heat insulating properties.

[0031] (Second Embodiment) Referring now to FIG. 4, the following describes a vacuum double structure according to the second embodiment. FIG. 4 is a partial sectional view of the vacuum double structure according to the second embodiment. More specifically, FIG. 4 is an enlarged view of a sealing member 30. As illustrated in FIG. 4, the vacuum double structure according to the second embodiment is configured such that a height of a spacer 32 is increased, so that a distance between respective facing surfaces of an inner wall member 10 and an outer wall member 20 is enlarged. With such a configuration, it is possible to further improve heat insulating properties.

[0032] Further, since the height of the spacer 32 is increased, a belt-shaped back-up ring 33a made of metal such as stainless steel is provided on an inner peripheral surface of the spacer 32. Similarly, a belt-shaped back-up ring 33b made of metal such as stainless steel is provided on an outer peripheral surface of the spacer 32. The spacer 32 is supported by those two back-up rings 33a, 33b.

[0033] Since the back-up rings 33a, 33b are provided, even if the height of the spacer 32 is increased, it is possible to restrain the spacer 32 made of resin and having elasticity from buckling in a vacuum state, for example. The other configurations are the same as those of the vacuum double structure according to the first embodiment, and therefore, are not described in detail.

[0034] Note that the present disclosure is not limited to the above embodiments, and various modifications can be made within a range that does not deviate from a gist of the present disclosure. For example, instead of the O-ring, other annular packing materials, such as an X-ring, a D-ring, and a T-ring may be used.