Using Radar Sensors to Measure Levels in Fruit and Vegetable Processing

A Dependable Vitamin Supply Thanks to Optimized Production

In the town of Gochsheim in the Franconia region of Germany, it is no longer just apples that are pressed, cut and pureed. They process domestically grown berries, vegetables, and fruits, plus exotic tropical fruits. They are used as the raw ingredients for their variety of high-quality fruit and vegetable products during the entire year.

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.

Bernd Thielmann, Plant Manager, Mainfrucht.


Standard Techniques Used in Food and Beverage Companies

Global food and beverage companies buy juice flavors, purees, and concentrates, plus a variety of frozen products and prepared foods. For example, there are apple and carrot purees, which are filled into baby food jars. Some other fruits and vegetables are processed into concentrates that are then employed as coloring agents. Vanilla ice cream normally appears so appetizing because it contains the pigment beta-carotene, which is produced from carrots.

The company Mainfrucht in the Franconia region of Germany produces high-quality fruit and vegetable products.

The company Mainfrucht in the Franconia region of Germany produces high-quality fruit and vegetable products.

Mr. Thielmann makes it a habit to double-check all the raw materials and their subsequent processing, so as to meet the high quality requirements of customers. Mainfrucht works closely with farmers in the region, who are the first link in their supply chain. The range of vegetables and fruit delivered are analyzed and examined carefully, because only uncontaminated, fresh produce can make the highest quality end product.

A refrigerated warehouse with over 12,000 pallet spaces verifies that the production facilities are utilized fully, even during months of low-harvest.

The production techniques have to be adapted continuously to the different varieties of fruit and vegetables, as well as brought up to date with new technologies. Blueberries need a totally different type of processing than carrots, for example. They utilize state-of-the-art technologies and computer-controlled production processes to guarantee the gentle handling of the valuable fruit and vegetable products, of whichever type.

Located in Gochsheim since 2000, Bernd Thielmann planned and developed the production facility, and is familiar with every tank, fitting and measuring instrument down to the smallest detail. His conclusion:

You purchase not just a measuring instrument, but the service and dependability that goes along with it. I want a reliable partner at my side, not just a supplier. For level measurement, we rely almost exclusively on VEGA sensors. I especially appreciate that VEGA comes immediately when there's a problem. And it's been like that for over 30 years.

Bernd Thielmann, Plant Manager, Mainfrucht.

VEGA Sensors

More than 100 different VEGA sensors are now in use. 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 multiple tanks.

The vegetables are heated in a trough cooker with a rotating heating coil. VEGAPULS 64 monitors the level here continuously.

The vegetables are heated in a trough cooker with a rotating heating coil. VEGAPULS 64 monitors the level here continuously.

VEGAPULS 64, the newest radar sensor, is employed in the carrot processing facility. Firstly, so that they can be peeled more easily, they are steamed. Using a VEGABAR pressure transmitter, The head pressure is controlled here. Next the carrots are 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 controls the input and feed speed, warns against overfilling, and oversees 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.

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.

Bernd Thielmann, Plant Manager, Mainfrucht.

If that wasn't enough of a challenge, the level at the lowest point of the vessel couldn't be calculated accurately with a hydrostatic pressure sensor either due to bridging. The result was that mash residues were frequently left in the vessel after emptying.

Since VEGAPULS 64 was installed, I haven't heard any more from that measuring point, and that's always a good sign.

Bernd Thielmann, Plant Manager, Mainfrucht.

Reliable Measurement

VEGAPULS 64 operates with a considerably narrower beam angle, which is the reason why it measures so well even in this confined installation situation. It also has a very wide dynamic range at the same time. There was no radar sensor for liquid applications on the market that covered a comparable range until now.

This means that reliable measurement is still achievable, even when there is build up or condensate, in this instance carrot puree on the antenna. Furthermore, the instrument can calculate the level precisely, even when the level is extremely close to the bottom of the vessel.

VEGAPULS 64 measures the level right down to the bottom of the storage tank.

VEGAPULS 64 measures the level right down to the bottom of the storage tank.

Radar sensors are also utilized on the four 500,000 liter silos that hold apple and carrot juice concentrate. These VEGA sensors were due to be replaced after 15 years of reliable operation. The sensors monitor the inventory and warn against overfilling and dry running in these silos.

Every millimeter is important in tanks of this size when it comes to level measurement, and of course new technologies offer advantages. Since the existing process fittings could be utilized, the sensors were easily mounted on them. Setup and commissioning were unproblematic, and four VEGAPULS 64 sensors now measure the level, with more precision and reliability than ever before.

Although both applications are very different, they clearly show the great attributes of VEGAPULS 64 for food and beverage applications, whether in large silos (storage vessels) or small containers (troughs), in extremely hot, steamy environments or in tanks with numerous internals.

This information has been sourced, reviewed and adapted from materials provided by VEGA Grieshaber KG.

For more information on this source, please visit VEGA Grieshaber KG.

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