JPH047517Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a duct valve for a scrap preheating device for an electric furnace, which is interposed in the horizontal portion of a duct that guides high-temperature exhaust gas from the electric furnace into a scrap preheating tank. It is.

[Prior Art] An example of the configuration of a scrap preheating device for an electric furnace equipped with this type of duct valve is shown in FIG.

1 in the figure is an electric furnace for melting scrap.
During the melting process, high-temperature exhaust gas is released. The combustion portion of this exhaust gas is combusted in the combustion tube 2, and then guided into the scrap preheating tank 3 to preheat the scrap therein, and then drawn by the fan 4 and discharged. Separately from the system of ducts 5 that forms such a flow, a system of ducts 5 that directly discharges the exhaust gas from the combustion tube 2 is constructed. Switching between these systems is performed by opening and closing a duct valve 6 interposed in the duct 5.

The duct valve 6 provided in such a scrap preheating device is not connected to the duct 5 due to its arrangement.
may be interposed in the horizontal part of the

Conventionally, the duct valve 6 interposed in the horizontal portion of the duct 5 has a structure in which a valve 6b that can be opened and closed is provided in the same inner diameter portion 6a having the same inner diameter as the front and rear ducts 5, as shown in FIG. ing.

[Problems to be solved by the invention] The exhaust gas emitted from the electric furnace 1 contains a large amount of dust such as iron oxide, while the gas after passing through the scrap preheating tank 3 contains oil and is viscous. be.

In the case of the conventional duct valve 6 described above, the dust D in the gas tends to accumulate in the front and back areas below the valve 6b, making it impossible to open and close the valve 6b. In order to avoid this, maintenance intervals had to be shortened, which was uneconomical.

This invention solves these conventional problems.

[Means for Solving the Problems] The duct valve of the scrap preheating device for electric furnaces of this invention is a scrap preheating device for electric furnaces that is interposed in the horizontal portion of the duct that guides the high temperature exhaust gas of the electric furnace into the scrap preheating tank. It is a duct valve of the equipment, and it is a place that communicates with the front and back of the duct in the horizontal part.
A small diameter part that is eccentric above the duct and has a smaller inner diameter than the duct is provided, and in this small diameter part,
It is characterized by having a valve that can be opened and closed.

[Function] The duct valve of the scrap preheating device for electric furnaces of this invention has the valve in the small diameter portion that is eccentric upward, thereby increasing the flow of gas in the vicinity of the valve and preventing the accumulation of dust. Prevents dust from settling near the valve.

[Example] An example of this invention will be described below with reference to Figures 1 and 2.
This will be explained based on the diagram. Note that the same parts as those in the conventional example described above are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, the reference numeral 7 indicates the duct valve according to this invention. Both ends of this duct valve 7 have the same inner diameter portion 7 having the same inner diameter as the duct 5.
a, 7a, and this same inner diameter portion 7
The horizontal portions of the ducts 5, 5 located in the front and rear are connected to a, 7a. Further, in the middle of the duct valve 7, that is, at the communication point between the front and rear ducts 5, 5, a small diameter portion 7b is formed which is eccentric upwardly than the ducts 5, 5 and has a smaller inner diameter than the ducts 5, 5. . In this small diameter portion 7b,
A valve 7c that can be opened and closed is provided. In this example, the valve 7c is a butterfly valve that swings about the horizontal axis O.

Inclined surfaces 7d, 7d are formed between the same inner diameter portions 7a, 7a and the small diameter portion 7b. These inclined surfaces 7d, the same inner diameter portion 7a near 7d,
7a is provided with dust outlet ports 7e, 7e facing downward. Dust outlet 7e,
7e is normally closed by lids 7f, 7f.

Next, the effect will be explained.

Naturally, the gas flow rate in the small-diameter portion 7b provided with the valve 7c is faster than other portions because that portion has a small diameter. Therefore, dust D is difficult to accumulate before and after the valve 7c. Therefore, the accumulation of dust D in the vicinity of the valve 7c is prevented, and the accumulation of dust D in the vicinity of the valve 7c is prevented.
loss of functionality is avoided. In addition, duct 5
If the overall diameter of the gas is made small to increase the flow rate, a pressure loss will occur due to the gas flow, which is not economical.

Further, since the small diameter portion 7b is eccentric upward, the dust D does not settle near the valve 7c. Therefore, the maintenance interval for the duct valve 7 due to the accumulation of dust D becomes longer.

In addition, in the case of this example, the dust outlet 7e,
7e, the dust D can be easily taken out by opening the lids 7f, 7f.

[Effects of the invention] As explained above, in the duct valve of the scrap preheating device for electric furnaces of this invention, the part where the valve is installed has a small diameter, so the gas flow in that part becomes faster and the dust is reduced. Since it is difficult to accumulate near the valve, loss of function of the valve can be avoided.

Further, since the small diameter portion where the valve is provided is eccentric upward, dust does not settle near the valve, and the maintenance interval for the duct valve due to dust accumulation can be lengthened.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining an embodiment of this invention, in which FIG. 1 is a longitudinal sectional view and FIG. 2 is a sectional view taken along the line - in FIG. 1. FIG. 3 is a longitudinal sectional view for explaining a conventional example. FIG. 4 is a schematic diagram of a scrap preheating device for an electric furnace. 1...Electric furnace, 3...Scrap preheating tank, 5...
...Duct, 7...Duct valve, 7b...Small diameter part, 7c...Valve, D...Dust.

Claims (1)

[Scope of utility model registration request] A duct valve of a scrap preheating device for an electric furnace that is interposed in the horizontal part of the duct that guides high-temperature exhaust gas from the electric furnace into the scrap preheating tank. A duct valve for a scrap preheating device for an electric furnace, characterized in that a small diameter part is provided eccentrically and has a smaller inner diameter than the duct, and the small diameter part is equipped with a valve that can be opened and closed.