4 September 1998

Crispers calling for washed

spuds

As crop purchasers continue

to call the tune on how

farmers present their wares,

Mike Williams takes a look

at potato washing

equipment – how it works

and its cost

GROWERS with contracts to supply potatoes to Walkers are required to wash the crop before delivering it to the factory. Equipment capable of washing potatoes is expensive, and this has created a demand for mobile washing equipment which groups of farmers can share.

The pre-wash idea comes from America where it was developed for hygiene reasons and reduce the amount of dirt arriving at the processing plant. With the idea firmly established here through Walkers, other leading processors are said to be considering a similar step which could force more growers into the washing business.

E W Downs is one of the three UK manufacturers offering mobile washing equipment to suit the Walkers contract, and director John Rodger-Brown thinks more processors will be following the trend.

"I think this is becoming a major, major issue for potato growers," he says. "I have no doubt more of the processors will be demanding pre-washed potatoes, but what is not certain is how the washing will be organised. A mobile washer is just one of the alternatives, and another option is a central washing facility which may be operated by the processor for growers within an area."

On-farm washing facilities for potatoes and other root crops are far from new, and the technology for the washing process is well understood. The problem is the quantity of clean water needed to wash tonnes of potatoes and the disposal problem presented by the dirty washing water.

Manufacturers have eased the problem by adding a water recycling system to their washing units. This makes water supply and disposal easier to deal with, but it also adds to the size and cost of the equipment.

There are three versions of the Haith Supawash from Tickhill Engineering, based on web elevator widths of 1200, 1500 and 1800mm. Washing starts in a water-filled pre-soak hopper, and on the 1800 model a spray section comes next, followed by a series of 11 rotary brushes powered by an electric motor with chain and sprocket drive.

As crop purchasers continue

to call the tune on how

farmers present their wares,

Mike Williams takes a look

at potato washing

equipment – how it works

and its cost

GROWERS with contracts to supply potatoes to Walkers are required to wash the crop before delivering it to the factory. Equipment capable of washing potatoes is expensive, and this has created a demand for mobile washing equipment which groups of farmers can share.

The pre-wash idea comes from America where it was developed for hygiene reasons and reduce the amount of dirt arriving at the processing plant. With the idea firmly established here through Walkers, other leading processors are said to be considering a similar step which could force more growers into the washing business.

E W Downs is one of the three UK manufacturers offering mobile washing equipment to suit the Walkers contract, and director John Rodger-Brown thinks more processors will be following the trend.

"I think this is becoming a major, major issue for potato growers," he says. "I have no doubt more of the processors will be demanding pre-washed potatoes, but what is not certain is how the washing will be organised. A mobile washer is just one of the alternatives, and another option is a central washing facility which may be operated by the processor for growers within an area."

On-farm washing facilities for potatoes and other root crops are far from new, and the technology for the washing process is well understood. The problem is the quantity of clean water needed to wash tonnes of potatoes and the disposal problem presented by the dirty washing water.

Manufacturers have eased the problem by adding a water recycling system to their washing units. This makes water supply and disposal easier to deal with, but it also adds to the size and cost of the equipment.

There are three versions of the Haith Supawash from Tickhill Engineering, based on web elevator widths of 1200, 1500 and 1800mm. Washing starts in a water-filled pre-soak hopper, and on the 1800 model a spray section comes next, followed by a series of 11 rotary brushes powered by an electric motor with chain and sprocket drive.

Washing is followed by a drying section with a bank of seven sponge rollers with squeegees added. Dirty water is collected and circulated through four 1.5cu m filter bags in a filtration tank, and then passes over a weir before being pumped back to the washing line.

Prices start at £30,000 for a unit mounted on wheels, and the Supawash can also be supplied on a road-going trailer to be towed by a truck.

The basic price of the Downs Washer with 1800mm web width, including 14 brushes and five rotary sponges is £23,500 plus £16,450 for a water recycling tank. The machine, developed from an American washer favoured by Walkers, is claimed to have the most effective water recycling system available.

Cost of a complete unit including the optional water settlement tank, all mounted on a semi-trailer, is £73,500.

With more than 20 washers sold so far, Peal Engineering is probably the market leader with the Prowash. This has what Peal calls a pre-soak tank, followed by a series of 16 brushes and then three rubber covered rollers. For the next stage customers can choose either a 2m long inspection table or a drying section with six sponge surfaced rollers. The unit has wheels and a drawbar, and prices start at about £35,000

Claimed throughputs range from about 20t/per hour for the smaller machines to a 60t/hr maximum for the biggest of the Haith Supawash models. Apart from one or two units sold to contractors, almost all sales have been to farmers. The farmer customers are either groups of growers sharing the capital cost, or an individual farmer who rents the use of the machine to other growers.

Shared use of a mobile washer works well when there are several growers in the same area, but long distance sharing can also be successful. A Peal Prowash purchased by JSR Farms of Driffield, Yorkshire is used on six farms in the East Riding, plus a further two farms almost 200 miles away in Suffolk. The machine is mounted on a trailer and is towed behind a tractor for local journeys but is pulled by a truck when travelling between Yorkshire and Suffolk.

Washer and recycling units from the Downs Washer. An 1800 web, 14 brushes and five rotary sponges perform the business. Cost of a complete unit including an optional settlement tank and trailer unit is £73,500.