As a result of almost 30 years of experience in the corrugating sector, Tiruna has developed various new products that significantly enhance the performance of single-facers and reduce the cost of producing corrugated board. Among these products we can find:
– DDS (Dry Dynamic System)
The roll has no syphon tube to remove condensation.
Steam enters the roll’s chamber directly via a central conduit placed where the siphon tube goes on traditional rolls.
The steam chamber is slightly tapered to create a slope to take condensate to the outlet. This is convenient both during operation and with the roll stopped.
The slope is calculated so that when the roll is stopped condensate flows quickly to the drainage well, and when it is spinning the thickness of the condensate ring is uniform throughout the steam chamber. The chamber is designed with the slope required to take the condensate to the outlet by gravity.
The drainage well at the condensate outlet concentrates all the condensate in the required place and manner.
This means that it goes through the horizontal holes towards the ring space, where the basic part which we call a “TIARO” is located.
The TIARO is a ring with several segments which are free to move within the ring space. It is moved by gravity and centrifugal force.
- When the ring is stopped only the outlets at the bottom, where the condensate flows, are opened. The outlets at the top, where the steam is, are closed off by the TIARO.
- When the ring spins at more than 90 rpm centrifugal force overcomes gravity and the TIARO expands, thus opening all the outlets for condensate and entrainment steam.
This increases outlet capacity when it is most needed, i.e. at high speeds.
The system can be installed on newly-built rolls for all corrugating systems. It must be fitted to both the corrugating and pressure rolls.
The steam installation must have entrainment steam, e.g. Baviera type, and there must be a pressure difference between the steam inlet line and the return line of at least 2 bar.
Entrainment steam can also be obtained by placing the corrugating and pressure rolls which receive all the steam in a cascade arrangement. Steam and condensate are separated at the exit from the rolls. The steam powers the pre-heaters and the condensate travels through the return line back to the boiler.
– IDD (Internal Dynamic Damper)
- All single facers suffer to a greater or lesser extent from vibration problems, especially at their second critical speed (around 180 m/min)
- This results in poor quality cardboard at these speeds, forcing machine speed to be reduced below the critical level, so that the corrugating machine is under-used.
- The IDD cancels out vibrations and give a solution to this problem.
- It can be installed profitably even on machines with pressure rolls which do not suffer much from vibration, as the speed increases which it makes possible mean that investment can be quickly recouped.
- For small flutes, the quality of cardboard produced is similar to that obtained on latest generation machines without pressure rolls.
- Solution of resonance problems on single facers
– Peripheral Heating
- Based on the DDS, which has been tried and tested over several years, we have designed a peripheral heating system which improves the quality of the cardboard produced.
- Improvement is achieved by homogenising roll temperature over the whole working width.
- Steam is input through a single conduit and recycled through multiple channels close to the surface. It is then led back inside and expelled by the siphonless system used in the DDS.
– Pyramid Profile
- After our wide experience with multiple profiles over the years, our Technical Department now presents the pyramid profile.
- This profile is based on the use of several different radii in the valley and peak of the profile.
- The paper pore is more opened when it reaches the gluing area of the single facer, and the contact area is smaller, thus reducing glue consumption.
- This not only reduces production costs but also improves the quality of the cardboard produced, as no additional moisture is absorbed.