Some designs contain a metal-to-metal seat seal; consequently,
needle valves are a good choice for high-temperature applications.
A unique arrangement of
needle valves regulates the flow of gas.
A new needle-drive unit for hot-runner valve gates is said to overcome several limitations common to single-shot
needle valves. Hasco America Inc., Arden, N.C., says these issues include splitting of the melt, which produces weld lines on flat surfaces; large overall installation height; and inaccurate scale-up from single-cavity development molds to multi-cavity production that uses a different nozzle type.
Most of the time, the regulators are a
needle valve -- a tapered pin that mates to a similar taper in the fitting.
"The sliding valve functions similar to a
needle valve, but the design eliminates the chance of black specks ending up in the part," says project leader Gerald Birner.
The Century system is equipped with both height and needle position sensors to maintain consistent
needle valve positioning.
Also new from Manner is a wear-resistant
needle valve for abrasive materials.
The M3 micro threaded
needle valve, with M3 threaded inlet and hose barb outlet, is for applications where space, leak-tightness, durability and light weight are required.
Users can choose from bolted bonnet, outside screw and yoke bolted bonnet, and integral screwed
needle valve process monoflange assemblies.
The
needle valve is totally contained within the nozzle housing and does not pass through the hot manifold.