GB2113806A - Valve for controlling the flow of molten material - Google Patents

Abstract

A sliding gate valve for a container 1 of molten metal comprises fixed and sliding plates 5 and 6 with ports 10 and 11 to move in and out of register to open and close the valve. The port 10 in the sliding plate 6 is formed as an insert of a material with good resistance to thermal shock. <IMAGE>

Description

SPECIFICATION Valve for controlling the flow of molten material This invention relates to a valve for controlling the flow of molten material from a container. A valve is in use wherein a sliding member, usually plate-shaped and known as a gate, has a port which can be moved selectively into and out of register with a flow passage in the wall of the container. The flow passage is conventionally defined in a refractory insert structure.

In accordance with the present invention the gate is formed of a refractory material with good mechanical strength and resistance to wear, and the port is in a separately fabricated insert formed of a material with good resistance to thermal shock.

The invention will be described by way of example. Figure 1 shows one general arrangement of a gate system for controlling the flow of molten metal from a container 1 with a refractory lining 2.

An orifice in the lower part of the container walls lined by a well-block made as described in British Patent 1,451,548. An inner nozzle 4 for the well is made using the refractory grain compositions of British Patent 1,429,723, which are ethyl-silicatebonded, or it may be one of the compositions sold under the Registered Trade Mark ZEDMUL. For the inner nozzle 4 the principal requirement is for good thermal shock damage resistance. A stationary plate 5 is positioned under the inner nozzle 4 and a sliding plate or gate 6 is positioned under and in wiping contact with the stationary plate 5. The sliding plate 6 is contained in a housing 7 and biassed by springs 8 to the functional position. A collector nozzle 9 is positioned under port 10 in the sliding plate and a port 11 is provided in the fixed plate 5 under the inner nozzle 4.In use the sliding plate 6 can be moved from the closed position shown wherein ports 10 and 11 do not register to an open position where they do. For the sliding plate 6 and the stationary plate 5 the principal requirement is for good mechanical strength and abrasion resistance. Consequently, these plates are usually made by a pressing process and often are tarimpregnated. The plates are usually made from alumina or a basic refractory for instance magnesia. In general, they do not have good resistance to damage by thermal shock.

In accordance with the present invention the resistance of a plate to damage by thermal shock is improved by placing an insert of a material having good thermal shock damage resistance in the orifice in the plate, through which the molten metal flows. This improvement is principaliy applied to the sliding plate 6 but may be applied to the stationary plate 5. Figure 2 is a drawing of a plate containing an insert 12 of this type. One advantage of this type of plate is that the diameter of the insert 1 2 can be changed to accommodate differing flow-rates of molten metal. There is consequently no need to make a series of plates with differing orifice diameters. One orifice diameter will now suffice for a wide range of flow rates.The insert 1 2 may be one of the compositions sold under the Registered Trade Mark ZEDMUL, or it may be made using the refractory grain compositions of British Patent 1,429,723, ethyl-silicate bonded. These are examples of some suitable ways of making the insert. The insert may also be made from tabular alumina grain bonded with ethyl silicate.

The ethyl silicate bonding may be simultaneous hydrolysis and gelation using an amine hydrolysis and gelation catalyst. Such hydrolyses and gelations are described in British Patents 574,752 and 612,622, also in U.S. Specifications 2,550,923 and 2,660,538. The ethyl silicate bonding may also be by acid hydrolysis and gelation, for instance as described in British Patents 1,356,249 and 1,373,560. The binding agent for the refractory grain may also be a co-gel of silica and alumina or zirconia, as described in British Patent 1,356,248. The insert may also be made by the process described in British Patent 1,574,210.The binding agent for the refractory grain used to make the insert may also be a hydrolysate of ethyl silicate made using a silica alcosol or silica aquasol, for instance as described in European Published Patent Application 0,041,394 and British Patent 1,518,975.

'In an alternative construction, the sliding plate and the collector nozzle are combined into one component. The ethyl silicate bonding process is particularly suitable for making such a combined plate and nozzle. Figure 3 is a drawing of a combined plate 10 and a nozzle containing a shaped insert 13 having good thermal shock damage resistance. This insert is made as previously described.

The preparation of the insert having good resistance to damage by thermal shock has been described with reference to ethyl silicate bonding.

Other methods may be used, for instance the alumina gel whose preparation is described in British Patent 1,427,708.

1. A valve for controlling the flow of molten material from a container, such valve including a sliding member with a port movable selectively into and out of register with a flow passage in the container wall wherein the sliding member is formed of a first refractory material with good mechanical strength and resistance to wear and the port is in a separately formed insert of a second refractory material with a good resistance to thermal shock.

2. A valve as claimed in Claim 1 wherein the sliding plate includes a dependant nozzle under the port.

3. A valve as claimed in either Claim 1 or Claim 2 wherein the lower end part of the flow passage is formed in a fixed plate across which a plate shaped sliding member moves.

4. A valve substantially as hereinbefore described with reference to and as shown in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Valve for controlling the flow of molten material This invention relates to a valve for controlling the flow of molten material from a container. A valve is in use wherein a sliding member, usually plate-shaped and known as a gate, has a port which can be moved selectively into and out of register with a flow passage in the wall of the container. The flow passage is conventionally defined in a refractory insert structure. In accordance with the present invention the gate is formed of a refractory material with good mechanical strength and resistance to wear, and the port is in a separately fabricated insert formed of a material with good resistance to thermal shock. The invention will be described by way of example. Figure 1 shows one general arrangement of a gate system for controlling the flow of molten metal from a container 1 with a refractory lining 2. An orifice in the lower part of the container walls lined by a well-block made as described in British Patent 1,451,548. An inner nozzle 4 for the well is made using the refractory grain compositions of British Patent 1,429,723, which are ethyl-silicatebonded, or it may be one of the compositions sold under the Registered Trade Mark ZEDMUL. For the inner nozzle 4 the principal requirement is for good thermal shock damage resistance. A stationary plate 5 is positioned under the inner nozzle 4 and a sliding plate or gate 6 is positioned under and in wiping contact with the stationary plate 5. The sliding plate 6 is contained in a housing 7 and biassed by springs 8 to the functional position. A collector nozzle 9 is positioned under port 10 in the sliding plate and a port 11 is provided in the fixed plate 5 under the inner nozzle 4.In use the sliding plate 6 can be moved from the closed position shown wherein ports 10 and 11 do not register to an open position where they do. For the sliding plate 6 and the stationary plate 5 the principal requirement is for good mechanical strength and abrasion resistance. Consequently, these plates are usually made by a pressing process and often are tarimpregnated. The plates are usually made from alumina or a basic refractory for instance magnesia. In general, they do not have good resistance to damage by thermal shock. In accordance with the present invention the resistance of a plate to damage by thermal shock is improved by placing an insert of a material having good thermal shock damage resistance in the orifice in the plate, through which the molten metal flows. This improvement is principaliy applied to the sliding plate 6 but may be applied to the stationary plate 5. Figure 2 is a drawing of a plate containing an insert 12 of this type. One advantage of this type of plate is that the diameter of the insert 1 2 can be changed to accommodate differing flow-rates of molten metal. There is consequently no need to make a series of plates with differing orifice diameters. One orifice diameter will now suffice for a wide range of flow rates.The insert 1 2 may be one of the compositions sold under the Registered Trade Mark ZEDMUL, or it may be made using the refractory grain compositions of British Patent 1,429,723, ethyl-silicate bonded. These are examples of some suitable ways of making the insert. The insert may also be made from tabular alumina grain bonded with ethyl silicate. The ethyl silicate bonding may be simultaneous hydrolysis and gelation using an amine hydrolysis and gelation catalyst. Such hydrolyses and gelations are described in British Patents 574,752 and 612,622, also in U.S. Specifications 2,550,923 and 2,660,538. The ethyl silicate bonding may also be by acid hydrolysis and gelation, for instance as described in British Patents 1,356,249 and 1,373,560. The binding agent for the refractory grain may also be a co-gel of silica and alumina or zirconia, as described in British Patent 1,356,248. The insert may also be made by the process described in British Patent 1,574,210.The binding agent for the refractory grain used to make the insert may also be a hydrolysate of ethyl silicate made using a silica alcosol or silica aquasol, for instance as described in European Published Patent Application 0,041,394 and British Patent 1,518,975. 'In an alternative construction, the sliding plate and the collector nozzle are combined into one component. The ethyl silicate bonding process is particularly suitable for making such a combined plate and nozzle. Figure 3 is a drawing of a combined plate 10 and a nozzle containing a shaped insert 13 having good thermal shock damage resistance. This insert is made as previously described. The preparation of the insert having good resistance to damage by thermal shock has been described with reference to ethyl silicate bonding. Other methods may be used, for instance the alumina gel whose preparation is described in British Patent 1,427,708. CLAIMS

1. A valve for controlling the flow of molten material from a container, such valve including a sliding member with a port movable selectively into and out of register with a flow passage in the container wall wherein the sliding member is formed of a first refractory material with good mechanical strength and resistance to wear and the port is in a separately formed insert of a second refractory material with a good resistance to thermal shock.

2. A valve as claimed in Claim 1 wherein the sliding plate includes a dependant nozzle under the port.

3. A valve as claimed in either Claim 1 or Claim 2 wherein the lower end part of the flow passage is formed in a fixed plate across which a plate shaped sliding member moves.

4. A valve substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

5. A valve substantially as hereinbefore described with reference to and as shown in Figures 1 and 3 of the accompanying drawings