| 摘要 |
Siphon freeze drain valve for an underground water sprinkling system including a line operating under water pressure, the drain valve being a U-shaped tube, one end of which is passed through a hole in the top of the line, the other end of which is outside the line at a lower level than the first end. A clamp and a seal holds the tube in the line against the force of the water in the line and prevents leaking around the tube. A check valve is in the end of the tube outside the line, the check valve selectively opened and closed to control flow through the tube and for establishing a siphon for draining the line.
|
