| 摘要 |
<p>A control fluid valve assembly is provided which is respondable to a pressure monitored fluid. The assembly preferably comprises first and second valve seats within a housing. A spool element is shuttleable within the housing near the valve seat by either manual or mechanical manipulation to first and second positions and is responsive to pressure variation within the monitored fluid to shuttle it to a second position. Balls are contained in first and second valve head groups and are carryable by the spool element, the balls being selectively sealingly engagable onto and wipable off of the valve seat means to control fluid flow of the control fluid within the assembly in response to the pressure monitored fluid. A plurality of seals are defined between the housing and the spool means to prevent fluid communication therebetween and to define flow passageways across the spool. The spool is shiftable to each of first and second positions and when in one of the positions pressure is substantially equalized within the flow passageways and the spool is statically stabilized. When the spool is shiftable to the other position, pressure differential defined across one of the seals urges and holds the spool in this second position. A control shaft is provided which is selectively communicable to the spool for shuttling the spool in one direction to one position. Piston means are provided which are responsive to predetermined increase and/or decrease in pressure of the monitored fluid for shifting the shaft to shuttle the spool.</p> |
