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Spring Actuated (Type A) Needle Shut-off Nozzles


spring shut-off nozzle

Spring actuated needle shut-off nozzles are generally used when processing low viscosity thermoplastics or when you want to run the screw (dosing/metering) while the mould is opening.

 

 

 

For Reliable and Economic Production

Technical Description

The correct nozzle size is determined by several factors that include the shot size, material being processed and the Melt Flow Index (MFI). Precise shut-off and reliable closing during screw run are the critical tasks of any needle shut-off nozzle and are the preconditions for trouble-free, economic production. The sole business at Herzog AG is the development and production of needle shut-off nozzles. They all feature a compact and modular design, trouble-free operation and optimized flow paths. Our reliable shut-off systems separate the flow of material at a location best suited for your process. For increased nozzle life we offer a wear resist option that is intended to be used when running filled polymers.

What can you expect from the Herzog needle shut-off nozzle?


nozzle cross sectionThe spring-actated needle shut-off nozzle Type A is opened by means of melt pressure and closed by means of spring force The axially moving needle in the shut-off valve is pushed, via the pressure pin, under spring force, against the shut-off surface of the nozzle thus closing the nozzle flow channel. When the melt pressure decreases to approximately 80 bar the nozzle closes. As the melt pressure increases during screw run, the pressure overcomes the springs force by pushing against the annular surface on the needle and the nozzle opens at roughly 200 bar.

For further information on Spring Actuated (Type A) Needle Shut-off Nozzles please complete the Enquiry Form.