| 摘要 |
A three plate system in sliding gate valves in which the stationary plate is essentially rectangular with one corner having a different configuration than the other three, and therefore keying into the correct insertion position at the upstream portion of the valve is disclosed. The tube holder or lower stationary unit is essentially rectangular, and it has opposed corners of one configuration (mirror images of each other) and opposite corners of a different configuration, the same being proportioned for mating relationship with the valve structure. The sliding gate has an asymmetrical orifice as disclosed in United States Patent No. 4,415,103. The slide gate also has asymmetrical feed rails on its lower portion which engage feed rails in the valve of differing widths to the end that when reversed the gate cannot be inserted. In addition to the non-reversible features just described, the invention contemplates the stationary plate as being asymmetrical with its longest face in the direction of exit of the slide gate to assist it in containing turbulence, and splash, at the time of insertion. The slide gate is asymmetrical on its face which coasts with the upper face, of the tube holder. This facilitates, in the ready position having the leading edge of the slide gate ,overlapping the trailing edge ofthe tube holder. The tube.holder in turn, is asymmetrical but the longest face.is in the direction of the position of the ready slide gate to be inserted. Thus in operation, when the gate is loaded, the sliding gate portion is passed along the rails until its leading edge contacts the trailing edge of the operating gate. At this time the leading lower face of the slide gate overlaps the trailing edge of the tube holder face thereby positioning the slide gate for insertion and to displace the gate to be removed. At the time of insertion the steel entering the orifice in the outgoing slide gate will tend to tumble upwardly, and because the long length of the stationary plate is above this area, it provides a greater surface to inhibit splash. Furthermore, upon shut off, provision is made to drain from the slide gate through the tube holder and into the mold. Finally, the sliding gate must be substantially the identical length of the tube holder so that the single cylinder which is used for exchanging the slide gate can also be used for removal and replacement of the tube holder. The valve itself has support and frame means for accommodating the just-described shapes of refractory. The valve in addition has releasable lock means in the ready plate area to receive a tube holder and tube by raising the same into position with or without a slide gate. The method, contemplates the sequential usage in a three plate sliding gate valve of a single slide gate sandwiched between a stationary upper plate and a tube holder in such a fashion that each one will mate with an offset "key portion" to thereby avoid reversal. The top plate leading edge in the direction of receiving the sliding gate is shortened, whereas the tube holder plate in the same direction is lengthened to the end that when the slide gate is moved into position it does not cause an excessive bending moment on the remote end of the tube holder plate and is in position to slide neatly in between the top plate and the tube holder plate once actuated in the direction of feed.
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