The spring-loaded shut-off needle opens during the injection cycle as soon as the injection pressure exceeds 280 bar and closes again as soon as the injection pressure falls below 100 bar. Due to the closure of the needle in the nozzle, no residual material is left behind and plastic leakage is prevented.

Spring loaded shut off nozzles are used in the processing of thermoplastics that are less sensitive and have a low viscosity, such as: PA, PPS, PE, POM, PP.

Advantages:

• Residual closure in the front of the nozzle.
• No material leakage during dosing.
• Shorter cycle time, higher productivity.
• Shut off foaming in the front of the nozzle.
• Compact design.
• Simple, quick installation.
• Economic solution.

Disadvantages:

• Not suitable for shear sensitive materials
• Pressure dependent opening and closing.
• Requires regular cleaning.

The shut off nozzles are supplied including heater band with built-in thermocouple type J.