- Retrofitable.
- Outstanding gauge uniformity and cooling efficiency.
- Design maximize the cooling rate and utilize maximum blower efficiency with proven gauge deviation reduction.
- The operating principles assure a quick response time to any input for thickness correction.
- Superb gauge uniformity while maintaining excellent output.
- Designed to match the exact characteristics of any polymer and provide excellent bubble control and gauge uniformity.
- Suitable for running low melt-strength materials at higher blow-up ratios.
- Repeatable settings of total airflow adjustments by a variable speed AC control for the blower motor.
- Do not require an additional blower or use compressed air
ProTune Breeze – gauge control system
PROTUNE
CONTROL CABINET
- Control cabinet with automatic gauge control software.
- Pc Based Operator Interface with 15” touch-screen colour screen, to display:
– previous and actual profile comparison (cartesian plot),
– actual profile (polar),
– profile trend diagram
BREEZE
AUTOMATIC AIR RING SYSTEM COMPONENTS
- High performance dual-lip automatic air ring.
- Last state-of-the-art design to start from best performance when automation is off, with highest cooling efficiency of the film with the best stability of the bubble.
- Automatic gauge control made with cartridge heaters, hence: – no maintenance required – no alteration of the air flow around the bubble – very easy to set-up
- Motorized adjustment of upper lip and chimney (option).
K-500 ROTOMAT
ONLINE THICKNESS SENSOR
- The capacitive sensor, on slewing ring, goes around the bubble and measures the film thickness along the circumference, over the frost line.
- The system calculates the thickness average value and the thickness actual values on each radial position (corresponding to the control zones of the automatic air rings).
- Different sizes of slewing rings available for lay-flats from 255 mm up to 3900 mm.
- Sensors with different coatings available: CRS (chrome coated sensor for standard films, excellent durability with abrasive films), PVD-2 (plasma coated sensor for slightly sticky films, good durability with light abrasive films), PTFE (coated sensor for sticky films, short lifetime with abrasive films).
- On demand, the PROTUNE can be interfaced with any other sensor available in the market.
BREEZE
CHAMBER DIMENSION
What is the function of the air ring chamber?
The purpose of the chamber is to homogenise the air flow arriving from the air inlets, uniforming it and creating what is called as a hurricane effect.
How much air is required to cool the bubble?
In traditional air rings a lot of air is lost to the environment without cooling the bubble.
The inserts inside the Breeze have been studied to minimise the possible air loss to the environment and therefore channel as much air as possible towards the bubble.
Space
The space needed by the stepper motor is more than that for the resistance. Therefore when using stepper motor the air ring has to be larger in diameter or else the number of control zones are reduced.
Because of the space needed by the stepper motor, the regulation zone is located further away from the film and therefore the control is less efficient.
Dual lip air BREEZE, fully powered by Doteco.
- Based Operator Interface with 15” touch-screen colour screen, to display:
- – previous and actual profile comparison (cartesian plot)
- – actual profile (polar)
- – profile trend diagram
- Control cabinet with automatic gauge control software
- Online film thickness sensor Kündig K-500 Rotomat
- Outstanding gauge uniformity and cooling efficiency
- Design maximize the cooling rate and utilize maximum blower efficiency with proven gauge deviation reduction
- The operating principles assure a quick response time to any input for thickness correction
- Superb gauge uniformity while maintaining excellent output
- Designed to match the exact characteristics of any polymer and provide excellent bubble control and gauge uniformity
- Suitable for running low melt-strength materials at higher blow-up ratios
- Repeatable settings of total airflow adjustments by a variable speed AC control for the blower motor
- Do not require an additional blower or use compressed air.
Air uniformity
- When using stepper motor control, since the location of the regulation is further away it is necessary to create walled zoning inside the air ring. This results in an air distribution which is not perfectly uniform due to the internal wall partitioning.
- On the contrary, if the partitioning walls are not done the regulated air will mix with the air coming from adjacent zones.
- If the air passage is completely closed, on using the stepper motor one risks in having zones without any air flow.
- On the other hand if the control is on air temperature, the air flow is not modified and this results in much better bubble stability.
- With stepper motors, when the air passage inside the air ring is closed the excess air has to go somewhere. Normally this excess air is distributed in the other adjacent zones resulting in an uncontrolled thickness variation in these adjacent control zones (this problem exists even in the case when the valve opens).
Maintenance
- The continuous flow of air generates dirt accumulating inside the valve. This results in valve blockage by time. On the other hand having resistances no dirt accumulates and therefore no maintenance is required.
- The real position of the stepper motor has to be continuously monitored. It is easily that stepper motors loose a step during the operation. On the other hand the function of resistances is much more simple.
- The stepper motors have a definite life due to a number of components that can break. On the other hand, resistances have an unlimited lifetime.
- Changing a stepper motor is not an easy job. The line has to be stopped which leads to material scrap when restarting the line.
Misconception: Why do our competitors have a larger chamber ?
- To dissipate excess air when valves are closed, thus trying to minimise the effect on adjacent zones
- Stepper motors need more space
- Some competitors place all stepper motor actuators inside the air ring chamber (when even a simple actuator malfunctions the whole air ring has to be dismantled leading to line stoppages)
Retrofitting a single air ring with a Breeze gauge profile control system
- Significantly improves film tolerances, greater consistency and smooth operation of downstream equipment resulting in reduced waste.
- The heater cartridges heat thick spots, minimizing them as they occur, resulting in the tightest possible gauge tolerances.
- Electronics that might fail and mechanical components affected by dirt have been removed from the system, making if very robust and safe to operate.
- A homogenous and stable air distribution provides a very balanced bubble making startups & change-overs easier and quicker, resulting in reduced waste.
- Service friendly technology – zero maintenance. Stepper motors need to be serviced and calibrated frequently leaving to line stoppages.
- Power consumption ranges between 4-5kW depending on air ring size. Each heater is 0.2kW at around 40% average load overall.
OPERATING MODE AND FUNCTIONS
- Advanced dual lip air ring BREEZE:
- – the Lower Lip provides initial quenching to strengthen the melt and also the “venturi effect” between the bubble and the cone to “set” the bubble;
- – Forming Cone: guides lower lip air and supports bubble while in the “semi-solid” state;
- – the Upper Lip provides the final “blast” of cooling air adjustment.
- The air flow is diverted into several radial flows distributed all around the ring, that impinge on the melt as it exits the die. The temperature of each individual air stream is controlled by cartridge heaters (control zones).
- The automatic control system gets the inputs from the thickness sensor and therefore adjusts the temperature of the air streams into each control zone, to compensate any deviation of the thickness profile:
- – if a thicker section is detected, the air temperature into the relevant control zone is slightly increased, hence the melt is going to be a little under cooled, enough to make the gauge thinner;
- – if a thinner section is detected, the air temperature into the relevant control zone is slightly reduced, hence the melt is going to be a little over cooled, enough to make the gauge thicker.
- The temperature of control zones can be manual adjusted from the operator screen. When in Automatic Mode, all adjustments are controlled automatically by the gauge control software.
