| 摘要 |
<p>The disclosure relates to a controllable valve structure, for throttling liquids under high pressure in a manner to minimize cavitation damage to the valve parts. The valve structure includes a cylindrical trim cage surrounding the valve seat and plug and formed with a relatively large multiplicity of passages for the radially inward flow of liquid. The orifices are so shaped and contoured that the effective throttling orifice of each is formed as close as practicable to the inner wall of the trim cage, causing formation of vena contracta in regions spaced as far as practicable from the walls of the trim cage. This reduces damage resulting from cavitation and correspondingly increases the useful operating life of the valve. In conjuction with the foregoing, the end face of the valve plug is recessed in the areas circumscribed by the annular valve seat, such that the inwardly displaced vena contracta are also displaced axially relative to the end face of the valve plug, minimizing cavitation damage to the plug, as well as to the trim cage. A specific valve construction is also disclosed, which achieves the theoretical objectives mentioned above which is, at the same time, capable of practical, economical manufacture.</p> |
