| 摘要 |
<p>A valve assembly for valving abrasive fluids. A ball valve member is provided for rotation in a body member, the body member having inlet and outlet bores therein. Tubular inserts of abrasion resistant material - such as boron carbide - are provided in the inlet, outlet, and a bore through the valve member. The inserts are selected so that cooperating arcuate sections formed at the ends thereof are of a length greater than or equal to the diameter of the passageways through the inserts. Also the diameter of the passageways is preferably selected so that it is much less than the diameter of the ball valve member so that during throttling the angle of deflection of the abrasive flow will be small. A purge fluid may be injected under pressure in spaces formed between the ball valve member and the body and inlet insert.</p> |
