| 摘要 |
A gas and resin backflow preventing device of a hot runner valve gate opening and closing device is provided to facilitate working of a valve pin with high accuracy by employing a super heat resistant O-ring, which prevents backflow of resin for producing molded products with various colors. A gas and resin backflow preventing device of a hot runner valve gate opening and closing device comprises a cylindrical body(50), a nozzle(70), a valve pin, and one or more sealing units. The nozzle is assembled together with the body by the same axis, having a valve pin guide bush(60) therebetween. The valve pin, penetrating the valve pin guide bush, opens and closes a resin injection port of the nozzle. The sealing units is disposed between the valve pin and the valve pin guide bush to prevent backflow of gas and resin, comprising an inner annular groove on an inner diameter of the valve pin guide bush, and a super heat resistant O-ring fitted into the inner annular groove making close contact to the outer diameter of the valve pin.
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