The needle type shut-off nozzle (NVD) is used to process thermoplastics and liquid media. The choice of nozzle size depends on the flow of injection volume (cm3/s).
The NVD (shut-off nozzle) is responsible for the clean separation of the molten mass and reliable shut-off during dosing and is the prerequisite for fault free, economic production.
The GT-NVD stands out with its compact, modular construction. It guarantees fault-free functioning and optimum flow geometry. The shut-off system separates the flow of the mass, depending on the process, at a defined point.
deployment of wear protection guarantees a long service life.
Description of function
The spring loaded NVD type A is opened by the pressure of the molten mass and is shut off by the power of the spring.
A needle that moves axially in the NVD is pushed by the power of the
spring via the pressure pin to the NVD’s outlet drill hole. The nozzle’s outlet
opening is shut. The nozzle opens with increasing molten mass pressure, which
operates via a ring surface on the needle against the power of the spring, at approx.
200 bar. The nozzle shuts off when the molten mass pressure decreases (80 bar).
The pressurised ring surface of the needle must be made larger (less opening
pressure) or smaller (greater opening pressure) when a different opening pressure
is required. The pressure spring is not modified, as this would affect its
service life. Temperature resistant material up to a maximum of 520°C is
selected for the spring.
- Shorter cycle times
- Dosing with withdrawn nozzle
- Greater process reliability when injection moulding
- Compact and robust construction
- All parts can be replaced
- Simple upgrade at any time
- User friendly
heating element and thermal sensor
pressure of 2000 bar
|Operating data||A0||A1 / A1.1||A2|
Injection volume cm3/s based on polystrene
||up to 45||up to 500||up to 750|
|Screw Ø [mm]||up to 18||20 - 50||up to 80|
||200 bar||200 bar||200 bar|
||2000 bar||2000 bar||2000 bar|