A large wine cellar in the northern-Italian province of Trentino now uses special pumping technology from Germany-based NETZSCH Pumps & Systems. The progressing cavity pump from NETZSCH works exceptionally smoothly, leaving wine unchanged, as tests have demonstrated. At the same time, the technology is so compactly installed that it can be moved wherever needed along with its switch cabinet, so the vintner can work at all tanks with just one pump.
Grapes from around 1,500 associated wine-growers are processed in the wine cellar in Trentino using modern stainless-steel tanks as well as traditional barrique barrels. Storage and distribution are divided over two separate sites approximately 800m from each other to be able to manage this large volume.
NETZSCH Italian branch general manager Stefano Olivotto said: "The wine has to be pumped underground over this distance for mixing, from one side of the village to the other."
It was vital that the product should not be damaged by shear forces, pulsation or fluctuations in pressure, and essential to prevent the formation of air pockets, which would cause frothing and increase oxidisation. In addition, the pump was intended to be used for all types of potential application and at all tanks in the wine cellar.
Wine quality unaffected thanks to gentle conveying
The company therefore chose a NEMO® progressing cavity pump. The pump operates via rotary displacement and is based on a multi-spiralled rotor running inside a matching negatively-spiralled stator housing. The accurately tuned geometry of the two components creates conveying chambers of the same size on the suction side with each rotation, moving the sensitive medium to the discharge side in fixed volumes with almost no pulsation and without strong shear forces. In contrast to lobe pumps, there is also no pressure fluctuation, as there are no pressure reversal points in the system. Each portion is safely transported through the pump in its stable chamber and gently released back into the pipe on the discharge side. Changing the length of the pipe does not have a negative impact on this gentle conveying.
The volume can be continuously adjusted at any time by adjusting the speed and it is even possible to reverse the direction of rotation with ease. Volumetric flow rates of between 8m³/h and 30m³/h are therefore achieved in the wine cellar, depending on the specific situation, with an average flow of approximately 25m³/h. The pump is generally run at a slower-speed in the wine cellar to ensure the medium is exposed to even lower forces. Various chemical tests performed by the wine cellar have already shown that the wine quality is not affected by the conveying system.
Mobile conveying system with good cleaning characteristics
In order to operate the system as a mobile unit the pump was mounted on a baseplate with wheels, including its switch cabinet, an inverter, a manometer and a special thermal protection system to prevent overheating and dry running. The drive is also flange mounted directly to the pump.
Olivotto added: "We chose this compact design because the pump is connected to different tanks and therefore pushed around a lot in the wine cellar."
As the design does not have to be disassembled when it is moved to a different site so that the device configuration is never changed, it is only necessary to connect the power supply to bring the pump back into use at a new location.
With an eye on food safety and neutrality in terms of taste, all of the conveying system’s components that come into contact with the product are made from specially approved materials. Only stainless-steel and FDA-tested elastomers are installed at these points. The metallic surfaces have a polished finish and the pump chamber is designed to be free of dead space and flow-optimised to prevent pumped medium adhering. The pump is also designed for easy cleaning. The wine producer also requested a system that could be cleaned easily from the outside using a water hose. Care was therefore taken in the design to ensure that there are no dead spaces on the exterior under the baseplate, the pump or the switch cabinet.