| 摘要 |
The backflow prevention valve comprises various embodiments for installation in a liquid conduit for the prevention of reverse flow therethrough. The valve is particularly well suited for installation in a fire hydrant, where it prevents the illicit backflushing of the water system with contaminants. The valve may be constructed for use with either dry barrel hydrants, i.e., where the water is drained from the hydrant when the water is shut off, or wet barrel hydrants, where water remains in the hydrant body at all times. The valve may be constructed with a cylindrical body or with a thinner ring for the body, depending upon the installation desired. Each embodiment includes a series of generally triangular leaves hinged about the inner circumference of the valve body, which close against the central control rod or against one another at their apices when water is not flowing therethrough.
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