| 摘要 |
A sliding ring non-return valve primarily for use with an injection molding machine utilizes a frame having cut therein one or more longitudinal grooves. Material flows around the outer edge of a flange surface, into an inlet area, and through the longitudinal grooves in the frame's outer surface before entering an accumulation volume. A ring, dimensioned to fit slidably around the frame, blocks material flow into the grooves while in an upstream position and allows material to pass through the grooves while in a downstream position. In an alternative embodiment, the non-return valve utilizes a frame that surrounds a central passage accessed by inlets. The outlet passage is located downstream of said inlet and connects the central passage with an accumulation volume. A ring is dimensioned to slidably fit around the frame. A flange surface limits the ring's upstream travel, while grooves in the flange surface throttle, or limit, material flow into the inlet area. In an upstream position, the ring blocks material flow into the inlets. In a downstream position, the ring allows positive material flow from the inlet to the outlet. The material backflow around a downstream restraining cap forces the ring to its upstream position prior to the injection stroke.
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