CN1007972B - Method and device for extraction of a glass ribbon at the outlet of a float furnace, and the flat glass obtained - Google Patents

Abstract

The present invention relates to a method for pulling flat-plate glass at an outlet of a floating furnace. According to the present invention, the excess pressure is generated at the position between a first pulling roller wheel (12) and a separate boundary line from a glass strip plate (6) of a molten pool of molten metal (7) by inert gas below the glass strip plate.

Description

Method and device for extraction of a glass ribbon at the outlet of a float furnace, and the flat glass obtained

The present invention relates to make sheet glass, it should be noted that at float furnace subexit drawn glass batten with float glass process.

Make with float glass process in the process of sheet glass, molten glass is put in the molten bath of a molten metal, be generally the alloy that tin or main component are tin, by means of drawing roller, with continuous batten cooling and the stretching that glass in the molten bath forms, by the drawing roller it is sent into one and be known as in the preheating oven of " broadening case ".

Make in the process of sheet glass in float glass process, the stretching of glass batten is a meticulous step.Stretching and transmission in order to ensure the glass batten, the glass lath will be asked has enough rigidity, so that support and transmit with drawing roller, but enter the roller plane that draws roller back broadening case in order to be shaped and to leave the tin plane, the glass batten is the unusual hag, normally and continuously of Seeking Truth again, and does not have the variation of optical property on batten.

There is some shortcoming in the existing stretching device.In the manufacturing processed of heavy sheet glass, its thickness of glass is approximately greater than 7 millimeters (mm), and this thickness is called " balanced thickness ", can cause that in the weight that draws the roller bearing upper glass vitreous luster degree degenerates.

On the other hand, in the manufacturing processed of extremely thin glass, its thickness of glass is approximately less than 2 millimeters (mm), and this will be to pull out the glass batten at a high speed, and this will cause molten metal overflow from smelting furnace.

The present invention proposes a kind of method of the outlet drawn glass batten at the floating smelting furnace, can avoid above-mentioned shortcoming.According to the present invention, below the glass batten, and first draws roller and separates position between the boundary line from the molten bath of deposite metal and glass batten, produces a kind of extra pressure by an inert gas plant.Rare gas element refers to respect to chemically inactive gas or gaseous mixture in the molten bath.Rare gas element is that the mixed gas of nitrogen and hydrogen is better.

According to the present invention, the extra pressure that the glass batten produces down makes the glass lath be tending towards rising in specified zone, and this has just reduced to draw at first effective weight of roller upper glass batten, and prevents to occur at glass batten lower surface the impression of roller.

Make sheet glass with float glass process, generally will draw roller and be arranged on one and be divided in the chamber, be divided into mutually independently compartment by the tightness system that draws roller and be located at its below and top.At each compartment front compartment particularly, be by the exit surface of smelting furnace, first draws roller and the roller closed unit is determined; The gas of the gas on glass batten top and glass batten bottom is isostatic on pressure.Guarantee the equilibrium of pressure by being divided into the lateral openings that exists between chamber sidewall and the glass bar panel edges.

According to one aspect of the present invention, because lower part of compartment has been introduced rare gas element in front, and the assurance air pressure isostatic lateral openings between enclosed compartment lower part and upper part and glass batten both sides, below the glass batten, just produce a kind of extra pressure, return flow line below the unique possible approach that makes the gas evolution that is input to compartment lower part is the exit glass batten of float furnace is in other words between the bottom of the lower surface of glass batten and stove opening.So just formed the directed forward backflow of rare gas element, and can only on the plane at smelting furnace outlet place, on the edge of glass batten, particularly flow at inside furnace.

In this case; one of superiority of the present invention is: the lower surface that the directed reflux gas of one side constantly scans the glass batten; can dispose the glass batten by the whole particles that bring out in the molten bath; on the other hand, can prevent that particle is accumulated near the unlapped part in the molten bath of smelting furnace outlet.

Another superiority of the present invention is for to utilize gas flow under suitable temperature, can also obtain increases this surperficial viscosity simultaneously to the also controlled cooling rapidly of glass batten lower surface, is specially adapted to the glass batten of big thickness.

Can also prevent the overflow of molten metal according to the directed backflow of gas of the present invention, particularly in the process of making extremely thin glass, during high speed pulling glass batten.Therefore the control of vertical and horizontal when this air-flow also helps the glass bar plate to be shaped can make the glass batten of relatively good optical property.

Under the effect of extra pressure, the glass batten leaves fusion pool when surface earlier, more than these superiority show more significantly.

A superior aspect of the present invention is the gaseous stream of input front compartment, has constituted a system in Lower Half and has been used for cooling off the included exit surface of float furnace.For fear of covering different expansion between metal sheet on the refractory wall and the fixing metal plate member, particularly for fixing molten metal, this molten metal can infilter the space between the refractory materials, and the metal sheet in etch exit, usually exit wall will be cooled between 200 ℃～300 ℃ degree, so that prolong the life-span of exit wall with cooling.Adopt following method can realize cooling: a chest to be embedded on the metal sheet, to have refrigerant to flow through (being inert gasses preferably), and enter the chamber lower part that is divided into that draws roller is housed for molten metal in the molten bath to exit wall.Therefore as mentioned above, according to characteristics of the present invention, cooling gas is inactive for pool of molten metal, and has been heated after it flows through cooling tank, and cooling gas produces extra pressure again and forms directed the backflow under the glass batten.

Another advantage is in the method for the present invention: refluxing has caused air pressure rising in the float furnace, thereby has reduced the danger of the air of infiltration from the outside to the molten metal oxidation.

The invention still further relates to a kind of modifying device of drawn glass batten in the float furnace.The inventive system comprises: a compartment on the smelting furnace outlet surface, with the smelting furnace outlet surface is an end, drawing roller by first is determined by the other end, below drawing roller, be equipped with and prevent gas following current escaping gas sealing element, and the sidewall of device, bottom surface and be used for airtight smelting furnace outlet surface, first draws roller, the device of lateral openings between device sidewall and the glass batten, these devices that link to each other with the glass batten are divided into upper part and lower part with compartment, its lower part has one independent " window " that be made of the outlet of smelting furnace lower part, it is exactly the part between glass batten lower surface and outlet bottom, and in order below the glass batten, to produce extra pressure, and at the device of the bottom of compartment input rare gas element.

This device also comprise a cooling tank that is connected on the float furnace exit wall on the other hand, this case after it flows through cooling tank, is pumped to lower part of compartment from outside input inert cooling gas.

At the edge of smelting furnace outlet, first closed unit that draws lateral openings between sidewall of roller and compartment is that graphite member by two moulding constitutes, its upper surface touches the lower surface of glass batten a little, these two graphite members are located at first roller and produce on the position of friction, and above-mentioned parts are arranged and have a structure of extending under the glass bar panel edges.After the air-flow that forms has touched the lower surface of glass batten, these graphite members have sealed the escape of glass batten both sides gases, force the gas that is input in the compartment to move forward, and, particularly overflow in the inside of float furnace from the edge of smelting furnace outlet plane upper glass batten.

To show other characteristics of the present invention and superiority by following description to apparatus of the present invention embodiment.

Fig. 1 is that section is economized sketch map, has represented a device that is used for from float furnace drawn glass batten.

Fig. 2 is the orthographic plan of same device.

The groove 1 that float furnace is done by refractory materials, groove top 2, sidewall 3 and outlet sidewall 4 are formed, and on the outlet sidewall 4 opening 5 are arranged, and are used for glass batten 6 after it is shaped the passage that pulls out from the pond of its molten tin 7.There is a metal sheet 9 to be covered in the lower section 8 of outlet sidewall, and a cooling tank 10 that supplies rare gas element to pass through is housed on metal sheet.Connecting one in body of heater exit surface back and be divided into chamber 11, pull out the glass lath by drawing roller 12 and 13 this chamber, and it is transferred to broadening chamber (this figure does not express).Be provided with dividing plate 14 and 15 on the top that draws roller, and its underpart is provided with gas-tight sealing 16 and 17, so just makes that being divided into chamber 11 comprises that drawing roller is divided into 18,19 and 20 3 compartments.Two of graphite typing elements 21 and 22, the one end is connected to cooling tank 10, and the other end be divided into chamber sidewall 23 and 24, first draws roller 12 and links to each other, up to the edge 25 and 26 of glass batten.Two typing elements are stretched about 20～25(cm) centimetres in that the glass batten is downward.The upper surface 27 of typing element slightly contacts slightly with the lower surface of glass batten 28.

In this structure, comprise on the lower section 29 that is divided into front, chamber compartment that draws roller being provided with cooling tank (10).By conduit 30 input gases.In the Lower Half of this compartment output throttling mouth 31 has been installed, has been used for through the cooling gas behind the casing.

This device is operated in the following manner.During the glass batten was made, cooling gas (being generally the mixed gas of nitrogen and hydrogen) was with 200 meters ³/ hour speed enter cooling tank, and, after that cooling gas has been realized its function as refrigerant, act on the exit surface of body of heater by this cooling tank, leave cooling tank then, be heated simultaneously and enter and comprise the Lower Half 29 that is divided into front, chamber compartment that draws roller.In this compartment, the lateral openings on glass batten both sides is closed, and gas is unique, and what can overflow is exactly the Lower Half at stove exit place below the glass batten, and this is unique available outlet.Therefore, formed (shown in dotted arrow among the figure) gas stream forward, and its lower surface with the glass batten is contacted, draw between the roller at exit surface and first, overflow on the limit by the planar glass batten of stove exit, and particularly overflow by glass bar edges of boards and determined two lateral access of metal pool at stove self.When rare gas element contacts with the lower surface of glass batten, just produce a kind of power that the glass batten is lifted, this power has further reduced the weight of above-mentioned glass batten on first drawing roller.

In order not exclusively to rely on the gas volume of input cooling tank, an extra rare gas element input can be provided in the bottom of compartment, if when opposite the needs arranged, the cooling gas of outside can be removed.

Claims (5)

1, a kind of method from float furnace exit drawn glass batten, the glass batten is pulled out the molten bath by means of at least one drawing roller molten metal in stove, it is characterized in that below the glass batten, draw between the boundary line that roller and glass leaves from the molten bath of molten metal at first, produce a kind of extra pressure of rare gas element, above-mentioned rare gas element is introduced into the outlet sidewall by smelting furnace, first draws lower part of the compartment that roller and tightness system thereof limited, and seal up the lower section that can allow glass batten both sides and the lateral openings of the air pressure balance between the top, and produce the gas of one backflow direction, after reflux gas enters and touches glass batten lower surface, at the both sides of above-mentioned glass batten venting, on the plane of the opening of smelting furnace He in the smelting furnace, discharge.

2,, it is characterized by the rare gas element of introducing compartment and be a kind of gas that is used for cooling off the exit wall of float furnace according to the method in the claim 1.

3, a kind of being used for from the device of float furnace exit drawn glass batten, comprising: a compartment (18) in smelting furnace outlet face back, the one end is limited by the smelting furnace outlet face, an end in addition draws roller (12) and tightness system (14 thereof by first, 16) Nei Bu sidewall (23,24) and a bottom surface (32) limit, it is characterized in that comprising in the said apparatus exit surface that is used for smelting furnace, first draws roller, the enclosed appts (21 of the lateral openings between sidewall and the glass batten, 22), said apparatus links to each other with the glass batten and compartment is divided into upper and lower (19), and be used for rare gas element is introduced the bottom of compartment, and produce the device of supercharging in the bottom.

4,, it is characterized by this device and comprise according to the device in the claim 3: a cooling tank (10) that is connected on the float furnace exit wall, discharge from compartment lower part by behind the cooling tank from outside input inertia cooling gas and at it.

5, according to the device in claim 3 or 4, the closed unit that it is characterized by lateral openings is the profiled part of two graphite, and contacts with friction with first drawing roller.

Images