Cutting the mustard

Unilever needed an upgraded dust extraction system for the dry mixing facility at the Coleman’s Mustard factory. They considered several providers for the project before appointing Fercell to design, manufacture and install a new centralised dust extraction system.

This might sound straight-forward enough, however, the dust extraction system needed to be sited on the factory roof, almost 30 metres up!

Many challenges faced…

The previous dust collection system used bag filters and due to the wet, clean-down which took place between production batches they had to handle a high percentage of moisture.  The result of which was a rapid loss in suction performance and a requirement to replace the filter elements on a weekly basis.

Such a situation had a significant impact on their operation, with poor control of airbourne dusts, increased down-time and high operating costs.

The solution was a Fercell CM 100 EHB water wash unit.  The self-induced spray wet scrubber system, is designed to cope with difficult fibrous materials and was developed to control dusts and keep the environment clean and safe from the pollution produced when handling dry food stuffs.

The CM 100 EHB dust extractor, constructed from fully-welded AISI 304 stainless steel, is equipped with an, attenuated, 18.5kW centrifugal, backward bladed, fan set with a cycle duty of 10,200 m³h at a static pressure of 2,200 pascals.

High up? No problems here

The historic site, which Coleman’s Mustard have operated from, for 168 of their 204 years, sits directly beside the River Wensum and overlooks Norwich City’s Carrow Road Football stadium.  The limited access presented some real challenges which required consideration and planning to get the plant onto the roof.

A full lifting plan was established, requiring a 25 tonne crane to lift the 2,000 kg dust extraction system over 30 metres on a 28 metre radius up to the roof.  All the while the facility had to continue operating as usual with goods coming and going, to ensure that the 3,000 plus tonnes of mustard it produces each year reaches dinner tables around the world.

Once on the roof the dust extraction unit was secured to a heavy-duty structural steel support frame, incorporating a galvanised access platform and hooped ladder for safe access.

Along with the issues experienced with the previous system’s filter failure, Unilever were keen to minimise the level of maintenance and the requirement to continuously remove waste material.

Save staff time…Install automation

The new dust extraction system was designed with a sediment separation hopper, equipped with a 4” automatic sludge discharge valve, powered by a FESTO actuator, which was connected to the existing waste water system.

The system control was programmed to operate the valve, at timed intervals, periodically purging a percentage of material through the valve assembly.

To ensure a consistent volume and flow of water within the system, the plant was specified with an automatic water level solenoid control, a 1,000 watt immersion heater and automatic ‘care-fluid’ (containing anti-corrosion and anti-bacteriological agent) dosing meter.

The connecting pipework passed through the fabric of the roof and connected to the waste water circuit which serviced the manufacturing facility.

Thanks to the near fully automatic control and periodic purging the dust control equipment can run with virtually no service requirement or operator intervention. Saving Coleman’s Mustard operations time and money in the future.

The key to success? Plan ahead!

The requirement to keep production going with minimal downtime during the installation was planned in four key stages.

The first stage was the external works with the mechanical lifting and siting of the dust extraction unit and access facility on the roof.

The second was the installation of a correctly sized and balanced centralised ducting system, using Fercell’s ‘kwik-fix’ programme to ensure constant flow with minimal resistance.  Designed specifically for pneumatic conveyance of material the ducting system is manufactured with a smooth bore, with large radius fittings, from high grade AISI 304 stainless steel.  The ‘kwik-fix’ ducting system uses external compression fittings for the assembly and connection of fittings to maintain the obstruction free internals and provide maximum flexibility for rapid installation and any future modifications.

The dust control ducting system was designed and installed to incorporate a minimum of a 3° split fall to ensure no siting water within the system, with water running towards the main unit.

The third stage was the only time when the production plant was out of operation.  During which time the old dust extraction systems were removed.  As they were installed with the facility build around them afterwards they required completed dismantling and carrying down over eight flights of stairs in their individual component parts.

Within a short time the newly installed centralised ducting system was connected to the various mixing, tipping and powder handling processes.

Directly after the fourth and final stage was completed, was the thorough examination and test of the local exhaust ventilation system (LEV) to document its benchmark performance, the new dust extraction system was in operation.

Immediate returns…well worth it

Even though the system specification and complexity of the installation represented a significant investment, the return on investment was very short due in part to the high cost of maintaining the previous dust extraction units.

Clearly you don’t need faith the size of a mustard seed to achieve the impossible, just a well thought out solution and a plan to follow… ‘Pass the Mustard, please’.