WHAT’S NEW?
What’s new on Hydro-Dyn press?
The motor behind Dr. Haupt’s R&D activities are the demand of Hydro-Dyn press users for
- improved product quality
- reduction of operational costs
- increase in line capacity
- increasing stability of press operation
Particular emphasis in recent years was placed on the following areas:
1 Scraper pads in the press out-feed
Scraping silicone oil from the steel belt in the press out-feed leads to a good contact of the steel belt to the press drum. This situation is improved by the use of special scraper pads in the press out-feed. Efficient oil scraping could be proven by V-shape scrapers.
2 Rounded oil grooves in Teflon pads
A new generation of Teflon pads with rounded oil grooves was developed and are in use in nearly most of the presses. This version shows less surface wear and better distribution of the oil in the area.
3 Overlapping pad edges
This technical solution was developed to minimise the leak flow between the Teflon pads, which virtually close this oil passage and keep the fluid in the press surface.
4 Avoiding or reducing leak flow under the pads
Development activities of particular importance were accomplished in work on leak flow in the press between heating platen and Al-plates with the Teflon pads.
This leak flow reduces the heat transfer in the press and consequently the efficiency of the machine.
A significant layer of silicone oil is usually found on the lower heating platen (see photo).
O-rings seal the gap between heating platen and Al-plates – but they are wear parts and loose their efficiency by and by (see photo O-rings).
2 O-rings in one groove were occasionally found in presses (see photo). A suction force from the flow between heating platen nozzle and Al-nozzle was assumed.
The suction effect was confirmed in a fundamental test with air (see photo).
Another test rig was manufactured working with hydraulic oil. Test on this rig proved the existence of a deep vacuum in the flow passage (see photo).
Further tests were done on a new test rig with pressure measurements around a Teflon pad (see photo below).
Based on these findings a complete new generation of Al-plates with Teflon pads was created. Complete presses were equipped with these pads and showed surprising and spectacular results. Pressure and temperature measurements in 2 production presses were accomplished, confirming the positive behaviour, more uniform oil flow in the surface and a better heat transfer in the machine.
Dr. Haupt will provide more details about this development upon request.
5 Modifying Teflon edge pads toward better product edge quality
Product edge quality has always been an issue in the R&D activities on Hydro-Dyn presses. A weak point in the design of the Teflon pads in the edge zone could be found and a new design was created.
This progress is still fresh and waits for a confirmation by the use of this technique in a production press.
Dr. Haupt will give details upon request.