JPS5910472Y2 - insulation flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulating flange, and particularly to an insulating flange suitable for use at high temperatures and under ultra-high vacuum.

Generally, piping for electrical machines, accelerator tubes for accelerators, vacuum vessels for nuclear fusion devices, etc. may require joints that electrically insulate both ends and prevent leakage, so-called insulating flanges.

Conventionally, as this insulating flange, one having the structure shown in FIG. 1 has been widely used.

In this method, an insulating plate 3 is interposed between flanges 2, 2 provided at opposite ends of substantially metallic tubes 1, 1, and these are tightened with insulating bolts 4, thereby connecting the tubes 1, 1 at both ends. It is electrically insulated and connected.

The insulating bolt 4 can be tightened by using an insulating washer 5, a washer 6, a spring washer 7, a nut 8, etc. as shown in FIG. Alternatively, there is one in which a female thread is cut directly into the flange 2.

In addition, for products that require airtightness such as those for vacuum equipment, a packing groove 9 is provided on the surface of the flange 2 or the surface of the insulating plate 3, and a packing 10 is inserted into this groove 9 to insulate it from the flange 2. By tightening the plate 3, a leak-free pipe joint is created.

However, since insulating plates, packing, etc. are made of organic materials, they have poor heat resistance and cannot withstand heating of several hundred degrees Celsius, which is necessary to burn out the released gas when used in ultra-high vacuum areas. There is a drawback.

For this reason, in some cases, the packing is made of a metal such as a metal O-ring, and the insulation of the insulating plate and the insulating bolt is replaced with an inorganic ceramic such as alumina in order to improve heat resistance.

However, ceramics are formed with a smooth surface on which rounded fine crystals gather, so the surface has severe irregularities and it is not easy to polish the surface of the ceramic.

For this reason, even if packing is used, there are drawbacks such as a large amount of leakage, making it impossible to use it for ultra-high vacuum applications.

The present invention was devised to solve these conventional problems, and its purpose is to provide an insulating flange that does not leak even when used under ultra-high vacuum conditions.

The present invention focuses on the fact that the conventional difficulty is due to the severe unevenness of the ceramic surface, and forms a metal film on the contact surface of the insulating member with the packing by vapor deposition, ion plating, sputtering, plating, etc. The surface is made smooth, thereby preventing leakage between the insulating member and the packing.

The present invention will be explained below based on an embodiment shown in FIGS. 2 and 3.

FIG. 2 shows the insulating member of the insulating flange according to the present invention. As shown in FIG. 2, the insulating member 13 is made of inorganic ceramic such as alumina and is shaped like a donut disk.

A through hole 11 for an insulating bolt (not shown) is bored in the peripheral end thereof, and both sides of the inside part of the through hole 11 of the insulating member 13 are formed by vapor deposition, ion plating, sputtering, plating, etc. metal film 12
．． Each of the 12 is depicted in its own form.

Then, the surface of the metal film 12 is polished as necessary.

On the other hand, the flange 2 that holds the insulating member 13 from both sides has a ring-shaped packing groove 9 formed at a position facing the metal film 12, as shown in FIG. It is also polished as necessary.

As shown in FIG. 3, a heat-resistant packing 20 such as a metal hollow O-ring is disposed within the packing groove 9 to seal between the flange 2 and the insulating member 13.

In the above structure, when the heat-resistant packing 20 is arranged in the packing structure 9 and the flange 2 and the insulating member 13 are tightened, the heat-resistant packing 20 is attached to the bottom of the packing groove 9 and the metal as shown in FIG. It deforms when it comes into contact with the membrane 12, forming a seal at this portion.

As explained above, according to this embodiment, the manufacturing method is relatively simple, it can be applied to large-diameter products, and there is no leakage at the seal portion even under ultra-high vacuum.

Furthermore, since the thickness of the metal film can be made thinner than in the case of metallization, there is no damage due to differential thermal expansion and the film has excellent heat resistance.

Furthermore, since polishing the surface of the metal film, which is performed as needed, is much easier than polishing the ceramic surface, the manufacturing time can be shortened.

The present invention has been described above based on preferred embodiments, and according to the present invention, there is no leakage from the seal portion even when used under ultra-high vacuum.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a conventional example, FIG. 2 is a partial sectional view showing an insulating member of an insulating flange according to the present invention, and FIG. 3 is a sectional view of a seal portion. 1...Flange, 12...Metal film, 1
3... Insulating member, 20... Heat resistant packing.

Claims (1)

[Scope of utility model registration request] In an insulating flange that connects a ceramic insulating member and flanges arranged on both sides of the insulating member via packing, a metal film is formed on the contact surface of the ceramic insulating member with the packing. An insulating flange characterized by: