摘要 |
An improved foreign particle resistant valve assembly having a pressure responsive diaphragm main valve member activated by a pilot valve which controls flow through small orifice passages whereby pressure forces are created across the diaphragm main valve member to permit and prevent flow through the main flow section of the valve. Several arrangements illustrate various configured foreign particle-screening passages that protect the pilot valve orifice passages from blockage. The screening may be an integral part of the valve body or may be a removable member to facilitate cleaning or manufacture, and may be adapted to metallic or plastic valves. Other embodiments provide the means to enlarge a pilot pressure drop orifice passage which would then be less susceptible to foreign particle blockage and could also be combined with the screening passage means of the first embodiment.
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