| 摘要 |
<p>A reduced pressure zone backflow preventer comprising a body 12 entirely made of plastic material, formed with an inlet port ( 14 ) accommodating an inlet check valve assembly 120 and an outlet port accommodating an outlet check valve assembly 122 . The check valve assemblies extend along a coaxial axis coinciding with a longitudinal axis of the body. A central space 60 formed between the check valves is accessible through a service opening in the body. A relief valve assembly 70 is received within the central space and a drain port extends from the space. The relief assembly is responsive to pressure differential between the inlet port and the space by a flow passage extending between the inlet port and an upper side of a pressure diaphragm of the relief valve assembly.</p> |
