Hidrostal delivers major energy saving carrot

A Hidrostal immersible pump.

Produce World is the largest grower and supplier of high quality fresh vegetables in the UK and one of the largest in Europe. It provides a wide range of conventional and organic vegetables to the major supermarket chains. All its produce is picked fresh from the fields and processed without the addition of any chemical additives.

That means when it comes to washing, an environmentally friendly but effective solution is required which is where UK pump manufacturer Hidrostal comes in. The company has supplied Produce World with an immersible pump to aid it in the pre-wash process at its Yaxley, UK site which deals exclusively in organic vegetables including carrots.

Upon arrival at the plant the carrots are off loaded from a lorry and pre-washed using recycled wash water. Produce World had previously used an enclosed web, open belt conveyor method in this process but the pump that Hidrostal has supplied is part of a new open catchment design with a sloping bench arrangement to the sump area.

The boom wash system aids the movement and flushing of newly arrived field carrots off the lorry at the very start of the process into the sump. The wash water is pumped using Hidrostal’s immersible pump to a rotary screened drum where most of the solids are filtered out before re-entering the boom wash system once more. This process occurs each time a lorry arrives with fresh field carrots.

The pre-wash process at Yaxley.

Abrasive media

The carrots from the field, when mixed with the water, leave a very abrasive media consisting of flint, stones, sand, soil, weed and the occasional carrot. The common approach to pump selection in this type of arduous application has always been to err on the side of caution and to compromise by sacrificing pump efficiency for the sake of a pump which can handle solids and fibrous material. The result is a forgiving impeller design but one which uses more power.

And that means it is costly. Produce World approached Hidrostal looking for a solution to this problem and it came in the shape of the firm’s Screw Centrifugal impeller. This involves a single spiral vane impeller being axially extended creating a large free passage for solids but at the same time maintaining an optimum hydraulic design leading to high efficiency, low shear pumping and low velocity at the pump inlet.

The Hidrostal pump retained the desired solids handling capabilities and has provided longevity in its operation. It has also ensured a reduction in maintenance costs, down time and operational spend associated with the cleaning and maintenance of the previous open belt conveyor method.

But most importantly, the Hidrostal immersible pump with its 5.5kW four pole, three phase motor has resulted in a reduction in power consumption of 50%, a huge power saving from the previous end suction style pump that required an 11kW motor.

“I have been very pleased with the performance of this pump over the last 18 months. It has gone beyond our expectations outlasting previous designs three times over,” said Kevin Lander, lead engineer for Produce World.