ZELTWANGER Thermomanagement, a company of the ZELTWANGER Group based in Tübingen, manufactures, among other things, corrugated fin rolling machines for the production of heat exchanger fins. A key process is the lubrication of the raw material in order to increase the service life of the forming rollers. The Swabian company has developed a retrofittable stand-alone lubrication unit for this process step.

Lamella heat exchangers are used in numerous technical systems, such as in building heating systems, air conditioning systems or in the production systems of many industries. Other important applications can be found in vehicles, for example for the front cooler, the air conditioning system and increasingly also for cooling systems of drive batteries. Due to the quantities, the automotive sector is a focus industry for the heat exchanger experts. Aluminum has become established as the fin material in this area, and is processed from coil. Special fin form rolls are used on highly productive corrugated fin rolling machines to create the typical wave-like contour of the fins. The belt speed can reach values of around 6.5 meters per second. Lubricating oil must be applied to ensure a long service life for the rollers. However, since the lamellae are soldered during subsequent installation, the oil must be completely removed again after forming. This is done by evaporation, which is why special evaporator oil is used.

In this context, Wladimir Leimann, Business Unit Manager at ZELTWANGER Thermomanagement, explains: “Our new lubrication unit only applies as much oil as is absolutely necessary. We are talking about minimum quantity lubrication. This is how we ensure the quality of the soldered connection. We have also opted for a stand-alone solution that can be integrated into any existing corrugated roll forming machine. Consequently, our technology is available to all manufacturers of heat exchanger fins.”

The ZELTWANGER concept and its advantages in detail can be described as follows: Two adjustable atomizer nozzles spray the strip material from both sides. The experts from Tübingen precisely adjust the nozzles to the oil available (viscosity, density). This means that the user receives a customized system. In addition, the lubrication unit automatically adjusts the spray width and oil quantity to the stored bandwidth and the current speed to ensure even coating, support optimal soldering results, and keep oil consumption efficient.

The user has a full range of options for the oil supply. They can fill the unit manually using a funnel, via an electric barrel pump and drip-free quick coupling, or via an existing plant pipeline. In each case, it is possible to fill the unit during production without stopping the machine. What is important here is that no pressure vessel is required because the oil is conveyed by a mechanical pump. Consequently, no oil mist is formed that would need to be extracted. The workplace remains clean and there are no additional costs. In addition, the small amount of oil that is sprayed over enters a filter and remains in the circuit. All in all, oil consumption is said to be reduced by up to 70 percent. The same applies to material consumption.

But the flexibility goes even further. The lubrication unit is not only suitable for aluminum and its special requirements, but also for materials such as stainless steel or copper. The corresponding parameters can be easily changed via the HMI. Furthermore, integration into pipe folding or pipe welding machines is also possible.

Video