Both wrappers can generally handle a high capacity, but there are clear fundamental differences:
Slip ring of Ring wrapper
Ø 2.400 mm, completely open, IP20
Slip ring STREMA® Arm wrapper
Ø 200 mm, completely closed, IP54
Operation: A large rotating ring with the film carriage moves vertically up and down around the load to be wrapped. The energy supply for the rotating parts is provided by a slip ring with sliding contacts. This slip ring also moves around the load. The rotating ring is supported by about 10 wheels.
Principle: The slip ring therefore has a large diameter (± Ø 2,400), the path of the sliding contacts over the slip ring is long and the peripheral speed is high. A lot of mass (ring, film carriage, guide rolls) must also be vertical moved to achieve this. The ring must always be lifted above the load to release the pallet. All this in combination with an open slip ring (IP20) where dirt has free access and where sparks formed can escape freely. In combination with dust and dirt, this can cause dangerous situations.
Operation: Only the film carriage mounted on the wrapping arm moves vertically up and down. The slip rings are mounted in the heart of the machine on top of the wrapper. A robust central bearing provides the rotational movement.
Principle: The slip ring can therefore be produced in a small diameter (Ø 200 mm), the distance to be travelled by the sliding contacts over the slip ring is short and the peripheral speed is low. In addition, little mass (only the film carriage) has to be moved during the vertical movements to achieve this. The wrapping head turns to the side and the pallet can release. All this in combination with a completely closed slip ring (IP54) where dirt has no access and where sparks cannot escape.