JPS6236526A - Gas discharge nozzle of inside-furnace watching optical fiberscope - Google Patents

Abstract

PURPOSE:To prevent blurring of an objective lens and obtain good visibility to along distance, by shaping radial gas flow paths divergent in such a way that they are formed with inclined surfaces leaving the objective lens for its center. CONSTITUTION:A gas discharge nozzle 21 on the front end of an optical fiberscope is composed of conical gas paths 22 formed on the periphery from the outside surface of an objective lens 3, throat 13 passed by the gas flown from these gas paths 22 and divergent part 14. The gas flow paths 22 faces radially the center of the objective lens 3 and axially they are of convergent shapes formed by conical surfaces 23 leaving the lens 3 for the front end. By this arrangement, gas discharged from the gas discharge nozzle finds scarcely any collisions on the axial line of the objective lens and also in its neighborhood allowing the gas to flow in the long distance, and consequently blurring of the objective lend becomes available and good visibility to a long distance can be prevented.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention is used to prevent fogging of the objective lens of an optical fiber scope used for monitoring the inside of a melting furnace, such as a converter, electric furnace, or blast furnace. Concerning a gas discharge nozzle to be discharged.

(Prior Art) FIG. 2 shows a discharge nozzle of a conventional optical fiber scope for monitoring the inside of a reactor. In this figure, 1 is an optical fiber bundle, 2 is a protection tube, 3 is an objective lens provided at the tip of the optical fiber bundle 1, and the objective lens is partially in contact with the side surface 5 and inner surface 6 of the 4Fi objective lens 3. 8 is a gas flow path formed between this lens holder and the objective lens.

Reference numeral 9 designates a lens holder which forms a gas flow path 10 communicating with this gas flow path 8 on the outer surface ll side of the objective lens and is in contact with the periphery of the outer surface of the objective lens; 12 a cylindrical throat portion 13;
and a widening part 14 which is formed to widen outward.
It is a holding component which is screwed onto the tip portion of the protective tube 2 with a threaded portion 15 provided on the outer periphery. Note that 16 is an elastic ring interposed between the lens holder 4 and the protective tube 2.

The objective lens 3 is partially held at its outer periphery by a lens holder 4, and the lens holder 4 and lens holder 9 are in contact with the inner and outer peripheries of the objective lens, respectively, and are fixed by screwing a holding part 12. .

In order to prevent fogging of the objective lens, purge gas is supplied in the direction of the arrow in FIG. 10 and the throat 13. It flows out into the widening portion 14 in the direction of the arrow.

However, the gas flow path 1 of the conventional lens holder shown in FIG.
0 is the shape whose width is parallel to the lens surface and decreases toward the center of the lens.

The gas flow ejected from the gas flow path IO is accelerated and directed toward the center of the objective lens, where it collides, consuming the energy of the gas flow and generating turbulence.

This turbulence further increases the turbulence by passing through the divergent part 14, and is dispersed to the outside while being accompanied by a large number of vortices.

(Problems to be Solved by the Invention) The conventional gas flow, after flowing out from the gas flow path of the lens holder, collides with the gas and creates turbulence. There is a general view that the distance traveled by the gas is short because the collision consumes and reduces the energy of the gas flow. However, since the inside of the P of the vC box, air furnace, and converter tatami is filled with volcanic smoke, it is strongly recommended that by purging all of the volcanic smoke using the gas flow, the coverage distance can be extended and objects as far away as possible can be monitored. desired.

Means for Solving Problem C) The present invention aims to solve the above-mentioned problem in an advantageous manner by solving the problem by eliminating the radial gas flow that was conventionally formed between the outer surface of the objective lens and the lens holder. The path is characterized by its tapered shape, which is formed by an inclined surface that faces toward the center of the objective lens in the radial direction and away from the objective lens toward the distal end in the axial direction.

(Example) Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and is a cross section in the (11) direction of the distal end portion of an optical fiber scope.

In this figure, l, 2, 3, 13, 14, 18th digits 2nd
Showing the same things as 1, 2, 3, 13, 14, 18 in the figure,
Optical fiber bundle and protection tube, respectively.

Objective lens, throat, diverging p part 1 bullet a ring is shown.

21 is a gas discharge nozzle which combines the lens holder 9 and the holding part 12 in FIG. The gas flow path 22 has a throat portion 13 through which the gas flowing out from the gas flow path 22 passes, and a widening portion 14 at the end.
However, unlike the conventional gas flow path 10, the width is not parallel to the objective lens, but it is tapered and formed by a conical surface 23 that faces toward the center of the objective lens in the radial direction and further away from the objective lens in the axial direction. It has the shape of

It is a threaded part for attaching the 241 lens holder and 25 gas discharge nozzles to the protective tube and for holding the entire objective lens.

In this example, the throat diameter DI=14 m, and the maximum diameter of the widening end D! = 18.7 m, gas equipment 1
When the gas flow pressure at the gas discharge nozzle was 5 Nnl/min and the gas flow pressure at the gas discharge nozzle was 7 kg/mG, the speed of the gas flow was necessarily higher than the speed of sound, and a sufficient visible distance was obtained. Note that for θI and 03 in Figure @1, 30°≦01≦75°.

It is sufficient if it is a range concavity of 5°≦03≦60′m.

(Effects) This invention is equipped with a gas discharge nozzle in which the radial gas flow path is formed by an inclined surface away from the objective lens toward the center of the objective lens and has a shape VC that widens toward the end. The gas flowing out from the discharge nozzle has very few collisions on the axis of the objective lens or in the vicinity of the 7, and the gas in the 1 dog portion is focused in the direction of the center line of the divergent part 14 and flows outward, so that the gas flow is This gas flow can flow over long distances because the energy loss associated with the gas flow collision is extremely small and the gas flow is focused rather than dispersed. Therefore, it is possible to prevent fogging of the objective lens and to enable viewing at a sufficiently long distance.

[Brief explanation of the drawing]

FIG. 1 is an axial cross-sectional view of the distal end portion of an optical fiber scope according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional optical fiber scope. 3...Objective lens, 14...9 parts widening at the end, 21...
・Gas discharge nozzle, 22...Gas flow path, 23...Slope agent Patent attorney Masaaki Akizawa 2 Mitsugai 7i'1 Diagram

Claims (1)

[Claims] (1) The objective lens of the optical fiber scope for in-furnace monitoring has a radial gas flow path on the outer surface side and around the objective lens in the direction of the center line of the objective lens. In a gas discharge nozzle having a throat portion and a diverging portion, the radial gas flow path portion is tapered and formed by an inclined surface facing toward the center of the objective lens in the radial direction and away from the objective lens toward the distal end in the axial direction. A gas discharge nozzle for an optical fiber scope for monitoring inside a furnace, characterized by having the following shapes.