JPH0336880Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an observation window attached to the furnace body of various vacuum pressure heat treatment furnaces such as vacuum pressure sintering furnaces and vacuum gas pressure quenching furnaces. It is something.

[Conventional technology]

Generally, in a heat treatment furnace, a part of the furnace body is usually provided with an observation window (peephole) so that the condition of the processed material inside the furnace can be visually observed at any time. The observation window is sealed with a transparent window glass such as Pyrex glass to ensure airtightness inside and outside the heat treatment furnace.

[Problem that the invention attempts to solve]

However, in the case of vacuum pressure heat treatment furnaces that carry out vacuum treatment and pressure treatment inside the furnace, which are becoming more and more frequently used these days, a high and low differential pressure state repeatedly occurs inside and outside the heat treatment furnace, so that pressure is applied to the window glass. There is a concern that this may cause damage. This means that even if the window glass is designed to have sufficient strength (thickness),
This is because opposite stress is applied to the window glass during the vacuum process and the pressurization process, so if there is any defect in the material, it is expected that fatigue failure will progress rapidly.

However, in the event that the glass of the observation window were to break, in a conventional heat treatment furnace that only performs vacuum processing, the atmosphere would be sucked into the furnace along with the broken glass. Although this was not as much of a problem from the standpoint of ensuring work safety, in the case of a heat treatment furnace that performs pressure treatment in addition to vacuum treatment, there is a risk of harm to surrounding workers.
That is, if the window glass breaks during the pressurization process, there is a risk that the high-temperature, high-pressure furnace gas will blow out from the observation window together with the fragments as a blast wave, exposing workers directly to the blast wave.

From the standpoint of ensuring the safety of the operation of the vacuum pressurized heat treatment furnace, this invention was designed to ensure that even if the glass of the observation window were to break and an accident occurred in which the blast wave was blown outside, the on-site workers could We will provide an observation window that has been improved so that it will not be directly affected by the blast wave.

[Means for solving problems]

To this end, the present invention is characterized in that a second window glass is arranged at an angle near the outside of the furnace, facing an observation window that is attached to the furnace body of the vacuum pressure heat treatment furnace and is sealed with a window glass. do.

[Effect]

If such a device is adopted, when it is desired to observe the inside of the furnace, it is possible to peek inside through the window glass of the observation window from the second window glass. On the other hand, in the unlikely event that the glass of the observation window is damaged and a blast is blown out from the observation window, the second window glass serves as a blast relief by guiding the blast upward along its slope, allowing it to escape from inside the reactor. The emitted blast wave does not blow directly into the workplace in front of the furnace.

〔Example〕

An embodiment shown in FIGS. 1 and 2 will be described below.

This embodiment shows an example in which the present invention is applied to an observation window attached to the furnace body (opening/closing door) of a vacuum pressure sintering furnace.
2 indicates a furnace body (chamber), 2 a heat insulating material, 3 a heater installed inside the chamber, and 4 a processing object set in the furnace core. An observation window 5 is attached to a required part (chamber front door) 1a of the furnace body 1, and the condition of the processed material 4 inside the furnace can be visually checked from outside the furnace at any time through a through hole 2a provided in the heat insulating material 2 (not shown). dotted line).

The structure of this observation window 5 will be explained in detail with reference to FIG. 2. A cylindrical protrusion 6 forming a window hole 5a integrally extends from the center of the chamber front door 1a, and a flange 6a at the tip thereof. At the same time, the transparent window glass 7 is attached to the window glass 7, and a hollow support fitting 8 is brought into contact with the outside of the window glass 7. Furthermore, by tightening the fixing bolts 9, 9, which are passed through the support fitting 8 to the flange portion 6a side, a structure is established between the two. The window glass 7 is tightly clamped. Note that seals 10, 10 such as O-rings are interposed on both side clamping surfaces of the window glass 7, and the window hole 5a of the observation window 5 is hermetically sealed with the window glass 7.

Therefore, a transparent second window glass 11 is additionally installed in the observation window 5 having the above-mentioned structure at a position near the outside of the furnace opposite to the observation window 5.
That is, this second window glass 11 is attached to a pair of upper and lower support frames 12 and 13 that are provided protruding in the extending direction of the window hole 5a, with their base ends 12a and 13a fixed to the flange portion 6a side, respectively. Its upper end 11a is pivotally supported on a pin shaft 14 supported between support frames 12, while its lower end 11b is supported between support frames 13, 13.
It is supported by a stopper 15 placed horizontally in between, and is arranged in an inclined state having an appropriate inclination angle with respect to the extending direction of the window hole 5a, while being foldable upward.

If a structure having double window glasses 7 and 11 is provided in this manner, when it is desired to observe the inside of the furnace, it is only necessary to look into the observation window 5 through the second window glass 11. In this case, if necessary, the second window glass 11 can be tilted upward as shown by the imaginary line in the figure, thereby allowing an even clearer observation of the inside of the furnace. The second glass 11 is always kept in the state shown by the solid line in the figure. On the other hand, in the event that the window glass 7 of the observation window 5 is damaged in this state, the blast wave blowing out from the window hole 5a along with the fragments of the window glass 7 will be supported by the support frames 12 and 13. second window glass 11
The light is guided by the slope of the surface and diffused upward as shown by the solid arrow in FIG. Therefore, the blast relief effect of the second window glass 11 prevents the blast from blowing directly into the furnace front work area in the extending direction of the window hole 5a, thereby ensuring the safety of the workers.

As explained above in the examples, the present invention solves the problem of the observation window in vacuum pressure heat treatment furnaces by simply adding a second window glass to the observation window attached to the furnace body. This is intended to provide an effective countermeasure against blast discharge accidents. Note that the mounting structure for the second window glass at the required position is not limited to the support frame method of the illustrated embodiment, and the design can be changed as desired. In addition, although the window glass of the observation window and the second window glass according to the present invention are referred to as "glass" for convenience of explanation, this does not mean to exclude the use of materials other than glass. Of course, other materials such as reinforced plastics can also be used for each window glass material. Furthermore, in the example, the case where a transparent plate-like body is used is shown so that the inside of the reactor can be directly observed through the second window glass, and the purpose of blast relief is achieved with its foldable mounting structure. In this case, an opaque plate may be used for this second window glass. In that case, the material of the opaque plate is not particularly limited, and may be a metal plate or the like.

[Effect of idea]

As described above, if the observation window of the present invention is employed in a vacuum pressurized heat treatment furnace, the safety of workers can be ensured from blast discharge accidents caused by breakage of the window glass.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the entire vacuum pressure heat treatment furnace showing one embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main parts thereof. 1...Furnace body (chamber), 1a...Chamber front door, 2...Insulating material, 2a...Through hole, 3...
Heater, 4... Processing object, 5... Observation window, 5a...
Window hole, 6... cylindrical protrusion, 6a... flange part,
7...Window glass, 8...Supporting metal fittings, 9...Fixing bolt, 10...Seal, 11...Second window glass,
12, 13...Support frame, 14...Pin shaft,
15... Stoppa.

Claims (1)

[Scope of utility model registration request] Observation of a vacuum pressure heat treatment furnace characterized in that a second window glass is tilted and arranged near the outside of the furnace, facing an observation window sealed with a window glass attached to the furnace body of the vacuum pressure heat treatment furnace. window.