CS238229B1 - Glass electric melting furnace especially for borosilicates melting - Google Patents

Abstract

The furnace, e.g. for melting of borosilicates, comprises a melting chamber 2 and a working chamber 3. The melting chamber 2 is provided at opposite side walls 6 with the two rows of electrodes, viz plate electrodes 10 near the bottom and bar electrodes 11 above them. The ratio of the number of plate electrodes 10 to bar electrodes 11 is 1.1-3:1. All the said electrodes situated at the same side wall 6 of the melting chamber 2 are connected to the same phase of a regulatable two-phase electric power source. <IMAGE>

Description

.Discover. It relates to the field of glass production, namely furnaces for all-electric melting of glass, in particular boilers.

The two-chamber glass furnace in the opposite side walls of the melting section is heated by two rows of electrodes, plate-shaped at the bottom, and rod-shaped electrodes above them. . The number of plate-shaped electrodes is in the ratio of 1.1 to 5 to 1, wherein the plate-shaped electrodes in one side wall of the melting portion are connected to the same phase of a common two-phase controllable power source.

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The invention relates to a glass electric melting furnace, in particular for melting borosilicates, a quadrangular plan view of a melting part, with a channel in the longitudinal axis and a submerged flow between the melting and working part. The melting portion is heated by plate electrodes at the bottom and rod electrodes above them.

A furnace according to United Kingdom Patent No. 8-5011 is known, heated in opposing walls of the melting portion at the bottom by plate electrodes. An oven reaches temperatures up to 1650 θΟ, ^{suitably p} ro melting. on ^comm la Oros ^{dB even if} átovýc ^hour glass. In practice, a specific melting capacity of up to 1.5 t / m ^e in 24 hours is achieved when melting the borosilicates in 24 hours, further increasing the melting capacity leads to an insufficient melting of the glass.

Although the combination of plate and rod electrodes is not used in practice in the electric melting of glass, it is described in USSR Authorization No. 5θθ 188. According to the present invention, the melting portion is divided horizontally into two zones.

... The larger and shallower zone for preheating the charge is heated by two rod electrodes in the front wall, in case of higher output by four type electrodes. The lower zone for melting and refining glass, smaller in area and deeper, is heated by two plate electrodes in the side walls. Power supply for each zone electrode is provided by separate and separate two-phase electrical circuits, in the case of using four electrodes, a three-phase current is used. This furnace is a complicated design of the melting part and is designed for small melting capacities. The placement of the rod electrodes in the front face of the melting portion limits the total area of the melting portion, since the active ejection of the molybdenum rod electrodes must not exceed a certain length at which the electrode bends or breaks spontaneously. can adversely affect.

These disadvantages are avoided or substantially reduced in the furnace according to the invention, which is characterized in that the plate and rod electrodes are located in opposite side walls of the melting portion. The ratio of plate electrodes to rod electrodes is 1.1 to 5 to 1. Both the plate electrodes and the rod electrodes in one side wall are connected to a common two-phase controllable power source.

The melting furnace with this mutual combination, the ratio of the number of electrodes, the placement and the wiring of the plate and rod electrodes achieves a favorable and progressive flow, intensive mixing and thus heat transfer. .

The overall result of these effects is then an increase in the average melting capacity of the furnace to a minimum of 2 t / m - per 24 hours.

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The furnace is flexible in terms of performance. For a given molten glass and a given electrode combination while maintaining the same source part, the melting power can be varied continuously in the range of + 20% while maintaining the glass quality, for example by controlling the power input of the electrical source.

An exemplary embodiment of the invention is described below and is schematically shown in the accompanying drawings, in which: FIG. 1 is a longitudinal axial section of the furnace; FIG. 2 is a plan view of the furnace in plane AA; FIG. 1 of FIG

The glass melting furnace 1 consists of a melting part 2 and a partially illustrated working part 6 which are separated from each other by the submerged flow rate 6.

The melting part 2 is formed by a vault 6, side walls 6, end walls 2 ^{and a} bottom 8 with a channel 6 in the longitudinal axis of the furnace 1.

The heating system consists of plate electrodes 10 and rod electrodes 11. The plate electrodes 10 are located at the bottom 8 of the side walls 6 of the melting part 2, eg in the number of 10 pieces. 6 pcs. All the rod electrodes 11 and the plate electrodes 10 located in the same side wall 8 are connected to the same phase of a common two-phase controllable power supply 12.

Melting proceeds as follows.

The batch and cullet charge is uniformly deposited over the entire surface of the melting part 2 on the so-called cold layer (Fig. 1), and the melting then proceeds in the vertical direction in the sense of a positive thermal gradient, meaning temperature increases with increasing depth. The melted and clarified glass flows out through the connecting channel 6 to the working part. The lower row of plate electrodes 10 creates a continuous homogeneous field of the electrical power to be provided in the space between them, the temperature maximum being at the upper edge of the plate electrodes

10. Of the total heating input, plate electrodes 10 supply approximately 70γ ^ / 90% energy to the glass, the rest being bar

238 229 electrodes 11 which create and support vertical convection. flow (see fig · 1). By placing and ratio of the number of plate electrodes 10 and rod electrodes 11 (FIG. 1, 2) according to the invention, an effective convection flow in the glass is induced so that the glass is intensely homogenized. The convection flow is several times stronger than the draw current, which stabilizes the furnace and is thus not dependent on glass intake.

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The plate electrodes form a heat-dam which prevents proniíkání convection currents ^ ^ ack to ^{the main} AVN ^¹H oo ^DBE Eq ^eh, stream ·

The furnace is designed primarily for melting heavy-duty, especially borosilicate glasses. For other types of glass, a change in the geometry and size of the furnace, including the source portion of the melting capacity, can be envisaged by machine and hand.

Claims (1)

SUBJECT. OF THE INVENTION 238 229 Glass electric smelting furnace, particularly for smelting boroeilikátů, ^CTY Ruhe ^l it ^to AC ground plan ^t, and ⁱ c ^also an ^AL em longitudinal axis and a submerged flow between the melting and working areas, heating plate electrodes at the bottom of the melting chamber, and bar electrodes over them; characterized in that the plate electrodes (10) are also rod-shaped. the electrodes (11) are disposed in opposing side walls (6) of the melting portion (2) and. the ratio of the number of plate electrodes (10) to the rod electrodes (11) is 1.1 to 3 to 1, wherein both the plate electrodes (10) and the rod electrodes (11) in one side wall (6) are connected to the same phase of a common two-phase a controllable power supply (12).