Top & tailing made easy
Trimming onions to the
pristine visual standards
demanded by supermarkets
is no easy task – especially
if the job is to be done cost-
effectively. Peter Hill
reports on a system that
seems to fit the bill
TAKE an onion in one hand and a pair of scissors in the other. Snip, snip and the bulb is precision trimmed. Now repeat the process several thousand times and it is easy to see why packers cannot get the staff to perform this operation by hand.
Besides, most packers find it is simply not economical to complete this task manually, says David Nicholson of Nicholson Machinery.
His company, based at Southery, near Downham Market, Norfolk, specialises in finding innovative solutions to current day problems, which is why it offers products from a sweeper to clean horse droppings from paddocks to large-scale soil sterilisers for glasshouse and field crops.
"With the Onion Top-Tail, we were trying to devise a system that would trim efficiently to a high standard and overcome some of the problems experienced with the type of equipment normally used for the job," he says.
The result is a series of steel rollers that start off as square section solid bars before being twisted into a tight spiral. These work against polypropylene covered plain rollers to snip away the top and tail of onions – as well as radishes, red beet and similar crops – destined for retail packs.
"Old type roller trimmers, with a spiral around a shaft, went out of favour because they tend to snatch and pull the neck out of onions," says Mr Nicholson. "Rotating blade topper/tailers then became the industry standard, but the blades need sharpening every two to three days, they need high speed electric motors so tend to be noisy, and the trimming process creates a lot of dust."
A lack of wear, as well as the fact that no scissor-sharp edges are needed, means that little or no maintenance is required.
"The first three roller pairs tend to wear most because they get to handle any debris that comes with the crop," says Mr Nicholson. "But they should still last 12 months and are the only ones that should need to be replaced."
With rollers arranged across the crop flow, spirals alternating left and right in sets of three, and two adjustable check rollers designed to make sure the bulbs pitch sideways at some stage, the device is also very effective, he says.
"Its unusual to see a badly trimmed onion coming through," he claims. "But because the roller-bed angle is adjustable, operators can balance throughput with the standard of trimming achieved."
The 1m wide Top-Tail, designed for trimming up on the end of a conventional topping and tailing line, will handle 5.5t/hour. The 1.4m and 1.8m versions, designed as the main topping and tailing device for a grading/packing line, are rated at 10t/hour and 14t/hour respectively.
"But we have a user in France putting onions through at up to 22t/hour because he doesnt have to work to such exacting standards of presentation," says Mr Nicholson.
Individual growers and packhouses have been quick to adopt the new technology. Barely 18 months after its introduction, Nicholson Machinery reckons to have sold 32 examples of the carefully patented device in the UK, with sales in France and Spain now picking up. *
Set into a grading/packing line, the Nicholson Top-Tail removes unwanted material from onions, radishes, red beet and similar crops.