Published by Farmers Guide, April 2009

Stirring silos offer an alternative to traditional grain storage systems

One of Dan-Corn’s largest on-farm installations, this set-up includes six 1,500t storage silos, and two 150t wet grain bins. It is situated on a pig unit that runs a feed mill to provide feed for itself and 15 other farms.

WHEN Hans Hansen took over the day-to-day running of Dan-Corn in the early 1990s he undertook a thorough review of the business to decide how it would operate under his control. Founded by his parents back in 1956, the company had traditionally manufactured wooden grain storage systems for use inside buildings, before diversifying into drying systems and on-floor storage installations, and even building its own fans.
The company had become well established across Denmark by the time Mr Hansen took charge, but with Danish farms becoming increasingly larger, it was clear the time had come for Dan-Corn to change direction.
According to the company’s export manager, Jens Erik Iversen, who is responsible for the UK market, the decisions Hans Hansen made allowed Dan-Corn to concentrate on making the most of its years of experience in grain storage and handling systems.
“The key change was that Dan-Corn would no longer manufacture any of the equipment it supplied,” he told Farmers Guide. “Instead it would source the best solutions from other manufacturers and use its experience to design and install complete grain storage solutions for its customers.”
The search for a supplier took Mr Hansen to the United States, where he visited, among others, the Iowa-based manufacturer Sukup, which made grain silos and mobile dryers. The two companies clicked, and two of Sukup’s grain dryers were soon making their way back to Denmark – one for the Hansen family farm and the other for resale.
“Mobile dryers, with their high capacity and competitive price, were relatively unknown at the time, so it wasn’t surprising that both of them were sold quite quickly and more were ordered,” Mr Iversen said.
Grain drying is required most years in Denmark and another of Sukup’s products that caught Mr Hansen’s eye was the stirring aeration silo.
“This was a particularly good product for the Danish market, and indeed throughout Europe, as it provided economical grain drying and storage with a good capacity and a reasonably small footprint,” Mr Iversen added. “Silos from 100-1,000t are available, so there’s a size to suit every farm.”
The drying silo has proved a best seller for Dan-Corn, which has the marketing rights for Sukup’s product range throughout Europe. The company sold 360 of them in 2008 alone, with 230 going to the home market and 100 to Sweden, with the rest spread throughout Europe – including two to the UK.
It’s not surprising when you consider how simple the concept is. You have a steel grain silo with a capacity of up to 1,064t that you fill from the top and empty from the bottom. At the top of the bin there is a two- or three-auger grain stirring system that pivots at the centre and has a drive wheel on a track running around the inside of the silo to allow it to rotate through 360 degrees. At the same time, the augers automatically move in and out from the centre of the silo to move all the grain in a flower-like pattern.
While the stirring is underway, hot air, typically 10-15 degrees Celsius more than the ambient temperature (heated by gas, oil or even hot water from a straw-fired boiler) is blown through the grain through the perforated floor.
“Because the grain is being stirred, the airflow is increased by up to 33%,” Mr Iversen said. “Typically you can reduce the moisture level by 4% in 10-14 days depending on the outside temperature and humidity, which is about twice as fast as a floor store.”
Dan-Corn says that its drying silo system costs about the same as a floor store of similar capacity, but it has a much smaller footprint and is much easier to manage.
“Everything is so much easier with a silo system,” Mr Iversen said. “You simply use a built-in intake system or an auger to fill the silo, and our unloading system to empty it again. You certainly don’t need a telehandler or loading shovel.”
Indeed emptying the drying silo couldn’t be easier. An auger (you can choose from capacities of 35-100t/hr) takes the grain from the centre of the bin – and then from a sweep auger – and either discharges it to a ground-level conveyor or to a high-level unloading spout. Whatever system is used, it will normally be controlled from a single, computerised panel that manages the whole operation.
Dan-Corn says that the economics of its drying silos mean that it is the most cost effective option for storing up to 2,000t (two 1,064t silos). If you need greater capacity, the company recommends taking a different approach.
“For large-capacity systems it makes financial sense to use a mobile dryer in conjunction with standard steel grain silos,” Mr Iversen said. “We have dryers capable of drying grain by 4% at throughputs of 20, 30 and 50t/hr, so again we have a system to suit any farm, especially if the dryer is used in conjunction with a wet grain bin.
“For industrial installations the dryers can be stacked to give outputs of up to 150t/hr.”
Dan-Corn’s standard grain silos are available with capacities of up to 19,000t of wheat (31.5m diameter and 36m high), although on-farm silos in Denmark tend to be no bigger than 1,500t to meet planning regulations that restrict the eaves height to 9m.

The stirring system in the Dan-Corn silo pivots around the centre and is pulled around a track on the inside wall.

Neat and tidy
Looking at existing installations in Denmark, the Dan-Corn offering certainly looks clean and efficient. All the constituent parts – including Skandia intake pits and conveyors where required – work well together to provide user-friendly grain storage systems that require minimal labour to run them.
All installations feature ladders or staircases to access the top of the silos, and platforms to ensure safe working when you get there. Where multiple silos have been built, walkways will always be provided to allow the quickest route between any two of them.
“When we begin quoting for a system we always recommend that the farmer should spend 10 minutes a day checking his silos,” Mr Iversen said. “Unless he can spare five minutes in the morning and five minutes in the afternoon to climb up the silo and make sure everything is working as it should, maybe this is not the best system for him.”
Dan-Corn works closely with its dealers and customers to provide the best solution for every situation and budget. The company will build a turnkey installation that includes conveyors for loading and unloading the silos and delivering the contents to where they are required, but it will just as happily supply a drying silo and an auger to fill it.
“We are European distributors for the Canadian-built Westfield augers that can move from 81-245t/hr of grain distances from 8-27m,” Mr Iversen said. “This means we can offer our customers the most cost-effective methods of handling their grain.”
Sukup’s dryers and silos, and Westfield’s augers, are all kept in stock at Dan-Corn’s warehouse at Hedensted, in the east of Denmark. The stock arrives in about 400 shipping containers each year and is then sorted and stored ready for dispatch.
The augers are supplied in kit form on transport frames that allow them to be stored efficiently before being loaded onto lorries for delivery. The silo’s meanwhile are also stored in kit form, with all the panels and ancillary parts palletised for quick dispatch – all the operational parts, like the stirring system, are fully tested before they leave the warehouse.
Once on the farm, Dan-Corn’s installation teams will typically take a week to erect a silo on the pre-prepared concrete base. They begin by building the silo roof at ground level, then using a jack system to build one ring of the silo at a time before raising the silo and adding another ring.
The way the individual steel sections and rings are bolted together adds to the strength of the silo, as does the use of vertical external stiffeners at regular intervals around the silo.
Only the Sukup mobile dryers are not supplied in kit form. They are fully assembled and tested by Dan-Corn staff before dispatch – a process that involves the fitting components for the European market to ensure the dryers meet CE standards.

UK coverage
Dan-Corn is now ready to take on the UK market and has appointed Stephen Dickons and Allfarm Installation Ltd, of Wickham Market, as a dealer for its products. The two companies have already attended three UK exhibitions – including Lamma and Grain UK – and have been encouraged by the reaction from farmers.
“We have delivered a number of dryers and silos into the UK market and felt it was time to establish a formal dealership arrangement to take care of sales, planning, assembly and maintenance, “Dan-Corn’s sales director, Jeppe Bergmann Rasmussen, told Farmers Guide. “We chose Allfarm Installation because it offered more than 30 years of experience in this sector and because we share the same business philosophy – offering the best products and outstanding service to customers.”
Stephen Dickons said UK farmers were beginning to express a great deal of interest in the solutions that Dan-Corn could offer.
“We’re confident that they will be impressed by the turnkey systems that have established Dan-Corn as the leading supplier in Denmark and Sweden, and one of the market leaders in Eastern Europe,” he said. “Today’s farmers don’t have time to take care of a large building project and run a farm, and we’re able to take on the whole project from initial design, through the planning application, and onto the build and commissioning phases.”