Saving labour in the inspection room

Samro has been building electronic clod and stone separators for years. When the Swiss company divested its agricultural branch in 2015, Tolsma-Grisnich from Emmeloord was the buyer of the production rights of the stone and clod separators. The TG Samro clod separator is especially popular with seed potato growers. Besides sales, the storage, processing and packaging specialist rents units to growers who occasionally have to deal with a problem batch. The problem with clods is more prevalent in some years than in others. It is a particular problem in growing years after a winter without frost or in years with a dry spring. An electronic clod separator saves growers a lot of work in the inspection room in those cases.

Seed potato grower Gerwin Luimes even started harvesting deeper after buying a TG Samro. "The machine takes out the extra clods anyway and by harvesting a bit deeper I have less half tubers." Traditional mechanical clod separators feed the potatoes over a steel roller, after which the potatoes end up on a different belt than the clods and stones. That is noisy, not very gentle on the product and the capacity is limited. The TG Samro, on the other hand, does the same job almost silently, product-friendly and fast. The users we spoke to usually have the machine in a fixed position, although the clod separator can also be moved. The machine is connected to the compressor to operate the pneumatic ejectors. In addition to 8 to 10 bar air, the machine requires a maximum of 3.8 kW power.

Spiral rollers

In front of the product conveyor belt there is usually a series of seven electrically driven PU spiral rollers, which remove the loose soil but also improve the transverse distribution of the product. The more evenly the product is fed, the more accurately the machine works. A pintle belt is also available. This removes mainly haulm and thus prevents accumulation of debris. By removing the foliage and loose soil, the separation process improves. The Koekoek partnership has the machine sort out field crops and uses a pintle belt after the clod separator. At Luimes and Bert de Bruyckere it is the other way round and the pintle belt comes first. Small potatoes or problem batches can go over the clod separator twice if required. It is also possible to remove loose soil, stones and clods separately. According to the users, the clod separator removes 90 to 95 percent of the clods and stones. With careful adjustment, clay caps can also be partially removed from the batch, although an extra time tipping over the box with potatoes to break the clay caps is recommended. The capacity and the separation result depend on the type of soil, distribution on the belt and the size of the product.

The machine does not work on iron-deficient soil

How does the Samro do it? A magnetic bar runs across the entire bandwidth. This bar polarises the clods, i.e. the magnet creates a magnetic field around the clod. The machine makes use of the fact that soil often contains iron. A copper plate in front of the ejector detects the magnetic field and activates the rubber covered cylinder - the ejector shoots the clods onto a discharge belt. A hood with a rubber flap prevents them from flying off in all directions. The technique does not work on soil with a too low iron content. That sometimes happens. The manufacturer tests the soil type beforehand to avoid disappointment. The machine has a different technique for sorting out the stones. There is a microphone under the copper plate. This 'hears' when a stone falls on the plate and then controls the correct ejector. Potatoes are not knocked out of the flow and continue their path in a straight line. Where some competitors use camera technology, the Samro works 'blind' and that makes the machine less sensitive to dust. Nevertheless, dust does occasionally settle in the pneumatic cylinders. Cleaning with an air gun is possible, but Tolsma-Grisnich advises the use of a vacuum cleaner. This prevents you from blowing dust into sensitive components. The rack with ejectors is mounted on a carriage that you can slide out of the machine. Thick clods or stones can sometimes cause a ejector to bend. At 135 euros a piece, the damage can be considerable. But the users take these costs for granted. Maatschap Koekoek has replaced quite a few in the meantime, De Bruyckere about five in two years. According to the manufacturer, too much air pressure is the main reason why the ejectors become bent. If a metal object is transported across the belt (a horseshoe, a bolt or a tool), the object is immediately 'grabbed' by the magnet and a number of ejectors go out. This problem is quickly recognised. The TG Samro saves at least one person in the inspection room and the investment is recouped fairly quickly. In addition, the product damage decreases and the separation accuracy increases.

Tolsma-Grisnich supplies three models of the TG Samro. The smallest (TG Samro 24 with 24 ejectors) and the middle size (TG Samro 44) are intended for the sorting area. The TG Samro 72 has a belt width of 250 cm and can sort up to 50 tons of gross product per hour. The TG Samro 72 is meant to be built behind a a receiving hopper. The smaller ones provide 10 to 30 tonnes per hour separation capacity. The rule of thumb is: the smaller the potato size, the lower the capacity. The size 28/35 mm often contains the most clods.

Rotary knob

Setting up the machine is not very complicated. There is one rotary knob for sensitivity. The sensitivity can be set separately for clods and stones. Lights indicate the set position. In addition, there is a simple touch screen on which you can read things. Users seldom have to adjust the settings for a different variety.

Three users about the TG clod and stone separator

Gerwin Luimes: Peace and quiet in the inspection room

Together with his brother Rudi, Gerwin Luimes runs an arable farm in Marknesse (Fl.) with seed potatoes as its main branch. "In the spring of 2020 we could already see that it would be a year full of clods. We then bought a TG Samro 24," he says. "My brother has an accounting background and he calculated that we would soon earn back the investment. We now sort with an average of one person in the inspection room. The capacity is 8 to 10 tonnes per hour - enough for our line. I like the fact that the discharge conveyor is as wide as our Schouten sorter. Tolsma-Grisnich thought along about the design and integrated the machine in the sorting line. The separation method appealed to us very much because the machine does not affect the product quality. And I am amazed at how much the clod separator gets out - even from a “clean” batch. A pintle belt for removing haulmes is a must. Unfortunately, it was not available ex-factory. Sometimes you have to blow the machine clean if the ejectors get stuck. Otherwise it works without any problems."

Review Luimes

+ Space to harvest deeper

+ Labour saving

- Pintle belt not available

- Ejectors get stuck by dust

Erwin Bosscher: Also for field product

Employee Erwin Bosscher of the Koekoek partnership places boxes with field produce in the double box tipper. Behind it is the TG Samro 44, which processes seven to eight boxes per hour. "The machine handles field produce with ease," he says. "Foliage/haulmes do not accumulate and the roller set still removes a lot of loose soil. Outside our own fields, we also rent land with stones - a legacy from the ice age. The machine removes them all. We keep them separate from the sifted soil. However, Bosscher does regularly have to replace a bent ejector. "They are quite expensive. Fortunately, they can be replaced quickly. You also have to keep the clod separator clean, otherwise the ejectors no longer slide in properly and they keep sticking out. After two seasons you can hardly see the rubber caps wear off. Maatschap Koekoek tested a Tolsma-Grisnich machine and was satisfied with the result. "We have one field with old sea clay that does not contain enough iron. Clods of that soil are not sorted out by the TG Samro, but otherwise the machine works fine."

Review Bosscher

+ Relaxed product inspection

+ Removes almost all stones

- Ejectors sometimes bent

- Replacing ejectors is expensive

 Bert de Bruyckere: Certainly saving two men '.

In the 2020 season, a lot of soil came with the seed potato harvest on the De Bruyckere farm in Aardenburg (Zld.). "It was a combination of heavy clay, poor soil structure and drought," says arable farmer Bert de Bruyckere. "We then purchased a TG Samro 24 and were able to save at least two people in the inspection room. In the growing year 2021 there were far fewer clods, but even now the machine speeds up the sorting process. Employees Marco Oudkerk and Jacco Basting joke that they can celebrate Christmas holidays a week earlier because of this. More importantly, the machine improves the quality of inspection - you no longer have to pick up clods. De Bruyckere estimates the accuracy at around 90 per cent. "Before, the product discharge conveyor would sometimes get stuck with large clods," says the farmer. "We have now lowered it and that has solved the problem. A pintle belt removes loose soil and foliage from the crop before the clod separator comes into action. We have no rollers for spreading. But that doesn't lead to any problems."

Rating De Bruyckere

+ Substantial labour savings

+ Easy fine tuning, also with clay caps

- Conveyor belt gets stuck with a lot of clods

- Ejectors sometimes bend

[1] While the potatoes are falling down, the rubberized ejectors eject stones and clods from the lot.

[2] The sensitivity of the clod separator is adjusted with a simple turning knob.

[3] The row of ejectors are mounted on a carriage. When you disconnect the plugs you can easily slide it out for maintenance.

[4] The machine can be further adjusted via a touch screen. The magnet is maintenance-free.

[5] There are seven spiral rollers in front of the product belt that remove loose soil from the batch.

[6] A flap with sensor ensures that the entire line stops if too large clods pass by.