JPS647236B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a blowing fan for high-temperature gas, and particularly to a structure of the fan that can safely continue blowing air even when exposed to high temperatures for a long period of time.

[Prior Art] Although blowing fans are widely used industrially, at present, there are extremely limited number of fans that can circulate high-temperature hot air.

Fans made of heat-resistant steel are known as high-temperature fans, but the temperature of the hot air that can be blown by this fan is at most 1000° C., and there are concerns about continuous use over a long period of time.

On the other hand, various ceramic materials are known for their heat resistance, and their use as materials for fans has been proposed. Although it is conceivable to construct the entire shaft from ceramic material, these parts generally have complicated shapes, and it is technically difficult to mold each part integrally. Furthermore, ceramic materials are generally brittle against mechanical impact, and taking all of these factors into account, it is currently quite difficult and disadvantageous in terms of cost to construct everything from ceramics.

[Problems to be Solved by the Invention] In view of the above, the present inventor has aimed to find a blower fan that can be easily realized and that can continue to be used stably even when exposed to high temperatures for a long period of time. As a result of various studies and examinations, we decided to construct the blades, which are the parts that receive the most thermal shock, from ceramics, and to construct the impellers to which the blades are attached and the rotating shaft to which the impellers are attached, from heat-resistant steel, as in the past, to reduce the temperature caused by cooling. We have discovered a high-temperature gas blowing fan that suppresses the generation of large thermal stress due to gradients and is configured to prevent cracks from occurring due to thermal stress.

[Means for Solving the Problems] Thus, the present invention has a blade made of ceramics, a blade attachment impeller made of heat-resistant steel, and a rotating shaft to which the impeller is attached, and the rotating shaft is mounted inside the blade. This is a blower fan for high-temperature gas that is cooled from the inside, and a space is formed between the rotating shaft and the impeller so that the tip of the rotating shaft that is cooled from the inside does not come into direct contact with the impeller. An object of the present invention is to provide a high-temperature gas blowing fan configured to be cooled by thermal radiation due to a temperature difference with a rotating shaft.

As the ceramic used for the blade in the present invention, for example, silicon carbide, silicon nitride, sialon, alumina, etc. can be used as appropriate.

There are no particular limitations on the means for forming blades using these ceramics, and any known means such as slurry casting may be employed as appropriate.

The present invention will be explained below with reference to the accompanying drawings showing one embodiment thereof.

In FIGS. 1 and 2, reference numeral 1 denotes a blade made of ceramics, and each blade is attached to a blade attachment impeller 2 made of heat-resistant steel by an appropriate means, for example, as shown in FIG. The attachment end to the impeller is enlarged and implanted. Further, the impeller 2 is attached and fixed to a rotating shaft 3 made of heat-resistant steel by shrink fitting or screwing. The rotating shaft 3 has a double-tube structure, and the inner tube 4 has an open end on the blade side. Further, it is supported by a fixed outer frame 6 via an oil seal or gland packing 5 on the side of the rotating shaft 3 extending on the side opposite to the blade side. The fixed outer frame 6 has a substantially cylindrical space 7 on an extension of the inner tube of the rotating shaft 3.

In this way, for example, cold water can be fed into the rotating shaft from the space 7 in the direction of the arrow. In addition, the rotating shaft is provided with appropriate holes and slits 8 in the fixed outer frame 6, and a portion of the outer frame 6 is provided with communication holes 9 with the outside, so that cooling liquid can be drawn from within the rotating shaft. Can be taken outside.

Furthermore, in the present invention, the part of the impeller 2 where the blades 1 are located, which is the part in direct contact with the high-temperature gas, is not made to come into direct contact with the rotating shaft 3, but is provided with a certain amount of space 10 as shown in FIG. put. The reason for this is that, as mentioned above, the blade section is exposed to the highest temperature, and the impeller section to which the blade section is attached is also at a high temperature.If this section comes into direct contact with the cooled rotating shaft, the blade will heat up. This is because there is a risk of the car cracking. Therefore, the impeller in this part is cooled by radiation. Cooling by thermal radiation referred to here is when two objects with different temperatures are placed across space, heat rays are emitted from each object, and in the case of a black body, the radiant energy is equal to that of the object. Absolute temperature is proportional to the fourth power, and in objects that are not black bodies, energy is radiated and absorbed multiplied by an emissivity smaller than 1, and the amount of energy transferred decreases, but as a result, heat is transferred to the high temperature side. This refers to the process of cooling by moving from an object at a lower temperature to an object at a lower temperature.

Reference numeral 11 denotes a pulley fixed to the rotating shaft 3 by appropriate means such as shrink fitting or screwing, and the rotation of the motor is transmitted to the rotating shaft 3 via the pulley by a belt or gear.

In this way, the heat-resistant steel such as the rotating shaft is also liquid-cooled, making it possible to blow gas at a higher temperature than before. Although the outer surface of the impeller 2 is exposed to the highest temperature along with the blades 1, in the present invention, as described above, the outer surface of the impeller 2 is appropriately cooled from the inside by heat radiation due to the temperature difference between the outer surface and the water-cooled rotating shaft. Therefore, it can withstand high temperatures.

However, in the present invention, the heat resistance of the impeller portion can be further improved by appropriately coating the outer surface of the impeller (FIG. 1, 13) along the outer surface with a ceramic material. Become. In this case, the ceramic material to be coated may adopt a fixing method similar to the attachment of the blade.

As for the ceramic material to be coated, those used to construct the blade described above may be suitably employed, but it is not necessary to use the same type as that of the blade.

The materials used for the rotating shaft and its inner tube used in the present invention include piping steel materials such as SUS630 and STBA, and steel materials for the rotating shaft.The materials used for the impeller include NCF1, NCF2, NCF3, and SUS310S series. Heat-resistant steel is used as appropriate.

The rotating shaft, inner tube, and impeller are all made of heat-resistant steel NCF3
It is particularly preferable to use this material because it has high heat resistance and is resistant to thermal shock.

Further, as a refrigerant used for cooling, usually cold water is used, but other materials such as silicone oil can also be used as appropriate. Gases can also be used as refrigerants, but liquids are more advantageous in terms of cooling capacity and circulation. Furthermore, rust preventives and other additives can be added to these liquids if desired.

[Effects of the Invention] As described above, the present invention cools the rotating shaft from within and also cools the impeller portion by heat radiation due to the temperature difference between the rotating shaft and the rotating shaft. Thermal stress due to the temperature gradient associated with cooling the impeller does not become excessive, the occurrence of cracks is avoided, and it is possible to create a high-temperature fan that uses ceramic blades and is stable for a long period of time, so its practical value is great.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating a main cross section of a fan according to an example of the present invention, and FIG. 2 is an explanatory diagram illustrating a main cross section of a fan according to an example of the present invention. 4...Double structure inner tube.

Claims (1)

[Claims] 1. A high-temperature gas blowing fan that has blades made of ceramics, a blade-mounting impeller made of heat-resistant steel, and a rotating shaft to which the impeller is attached, and that cools the rotating shaft from within. A space is formed between the rotating shaft and the impeller so that the tip of the rotating shaft, which is cooled from the inside, does not come into direct contact with the impeller, and the impeller is cooled by heat radiation due to the temperature difference between it and the rotating shaft. A blower fan for high-temperature gas.