Look behind the scenes
Due to their sensitivity, wines are considered to be a difficult fluid to pump, while carbonated wines present completely different challenges: Each variety, for example, has a special carbon dioxide overpressure that must be observed. At the same time, the released CO2 increases the tendency of the beverage to foam, which impairs the quality of the goods. A large Upper Italian winery has therefore been using a particularly low-pulsation, hygienically safe rotary lobe pump. This T.Sano® pump guarantees not only the desired pressure over the entire pumping distance – and thus the quality of the wine – but also reliably prevents the unwanted development of foam. In this way, more precise dosing and better barrel emptying is achieved. The complete metal design of the pump and a drive without a lubrication system guarantee food safety and a perfect taste experience.
Whether lively or brisk, bubbles in a carbonated, champagne-style sparkling wine, for example, make you tingle. The amount and pressure of the CO2 are therefore not left to chance, but rather each variety has its own characteristic formula. This formula even determines the typification: Only wines with a carbon dioxide overpressure higher than 3 bar at 20°C are fully sparkling wines (spumante), while those from 1 to 2.5 bar are semi-sparkling wines (frizzante). To guarantee the desired amount and pressure of carbon dioxide, the entire production facility of the winery in Piedmont therefore operates under controlled pressure conditions up until the moment of isobaric bottling. Nitrogen is used as an aid to create still wines at 0 bar and particularly fizzy wines at 5 bar according to variety. This protects not only the special composition of the wine, but also prevents undesired foaming, which can make complete batches unusable in extreme cases.
The function of the pump is based on two rotary lobes, which counter-rotate, thus transporting the medium from the suction to the pressure side. Since pumping is performed purely according to the positive displacement principle here, there is no possibility of pressure fluctuations or shearing forces. "In actuality, this type of pump does not pressurise the medium but rather only pumps against the existing counter-pressure – 1 to 8 bar in this case," says Alessandro Modenini, the NETZSCH sales representative responsible for the project. A gentle, continuous delivery without any turbulence that could lead to foam is guaranteed and the organoleptic characteristics of the respective wine remain reliable. An additional advantage of this technology is the constant flow rate, which can be precisely monitored in contrast with pumping with gas pressure. The delivery volume does not depend on the viscosity or consistency of the medium and is determined solely by the speed of the rotary lobe. In this way, the product can be dosed precisely using the speed control, which simplifies bottling and minimises production fluctuations. The rotary lobe pump also is self-prim so that storage containers like wine tanks can be emptied almost completely without great effort. Since excess must be disposed of, this improved yield could noticeably increase the production profits of the winery in comparison with the previous method. To meet food safety guidelines in addition to the economic aspects, all components used in the T.Sano® rotary lobe pump that come into contact with the medium are designed in stainless steel. Forced ventilation was also integrated for safety reasons to protect the motor against overheating. T.Sano® has therefore been running malfunction-free at the Piedmont company for a year and pumping 7 to 10 m³ wine, both semi-sparkling and sparkling wine an hour at low speed