VEGAPULS 64 measures levels reliably in fruit and vegetable processing

But it's no longer only apples that are pressed, cut and pureed in the town of Gochsheim in the Franconia region of Germany. Throughout the whole year, they process domestically grown fruits, berries, vegetables as well as exotic tropical fruits and use them as the raw ingredients for their range of high-quality fruit and vegetable products.

 "Our focus is the pressing, puréeing and conditioning of fruits and vegetables, as well as the bottling and packaging of the products made from them," explains Bernd Thielmann, plant manager at the site. International beverage and food companies buy purees, juice flavours and concentrates, along with various prepared foods and frozen products. There are apple and carrot purees, for example, which are filled into baby food jars. Other fruits and vegetables are processed into concentrates that are used as colouring agents. Vanilla ice cream usually looks so tasty because it contains the pigment beta-carotene, which is also made from carrots.

To meet the high quality requirements of customers, Mr. Thielmann makes it a habit to double-check all the raw materials and their subsequent processing. The company works closely with farmers in the region, who represent the first link in their supply chain. The varieties of fruit and vegetables delivered are carefully examined and analysed, because only fresh, uncontaminated produce can become an end product of the highest quality. A refrigerated warehouse with more than 12,000 pallet spaces ensures that the production facilities are fully utilized, even during low-harvest months.

 

The production methods must be continuously adapted to the different fruit and vegetable varieties, as well as brought up to date with new technologies. For example, carrots require a completely different type of processing than blueberries. They use state-of-the-art technologies and computer-controlled production processes to ensure the gentle handling of the valuable fruit and vegetable products, of whatever kind.

Bernd Thielmann planned and developed the production facility, which has been in Gochsheim since 2000, and knows every tank, every fitting and every measuring instrument right down to the smallest detail. His conclusion:

At the production site, hydrostatic pressure transmitters as well as radar level sensors of type VEGAPULS 61, 62, 63 and 65 from VEGA measure the level in numerous tanks. A total of more than 100 different VEGA sensors are now in use.

The newest radar sensor, VEGAPULS 64, is used in the carrot processing facility. First they are steamed so that they can be peeled more easily. The head pressure is controlled here with a VEGABAR pressure transmitter. The carrots are then mashed via a screw conveyor with a mill and heated in a trough cooker. A VEGAPULS 64 was installed at the end of this unit. It warns against overfilling, controls the input and feed speed, and monitors the emptying process. The measurement situation with pressure transmitters was very unsatisfactory until now, but this was not due to the measuring instrument but the installation conditions," explains Thielmann.

The trough cooker contains a rotating heating coil and other components. The outlet of the vessel has a conical bottom that narrows at the end. In this area, air pockets are constantly formed inside the hot carrot mash. This always led to overfilling," recalls Thielmann. And if that wasn't enough of a problem, the level at the lowest point of the vessel couldn't be measured correctly either with a hydrostatic pressure sensor because of bridging. The result was that mash residues were often left in the vessel after emptying.

The reason why VEGAPULS 64 measures so well even in this confined installation situation is that it operates with a considerably narrower beam angle. At the same time, it has a very wide dynamic range. Until now there was no radar sensor for liquid applications on the market that covered a similar range. This means that reliable measurement is still possible even when there is condensate or build up, in this case carrot puree on the antenna. What is more, the instrument can measure the level accurately even when the level is very close to the bottom of the vessel.

Radar sensors are also used on the four 500,000-litre silos that hold carrot and apple juice concentrate. After 15 years of reliable operation, these VEGA sensors were due to be replaced. In these silos, the sensors monitor the inventory and warn against overfilling and dry running. When it comes to level measurement, every millimetre counts in tanks of this size, and new technologies of course offer advantages here. Since the existing process fittings could be used, the sensors were simply mounted on them. Here, too, setup and commissioning went without a hitch and four VEGAPULS 64 sensors now measure the level, with greater reliability and precision than ever before.

Although the two applications are very different, they clearly demonstrate the universal talent of VEGAPULS 64 for food and beverage applications, whether in small containers (troughs) or in large silos (storage vessels), in extremely hot, steamy environments or in tanks with many internals.