Joseph Ash Galvanising

In 2008 Lührfilter Ltd designed, manufactured, installed and commissioned a filtration plant to de-dust a galvanising bath at Joseph Ash Galvanisers in Walsall, West Midlands. The system was required to handle a gas flow of 22,000 Am3/hr at 60OC, which contained Zinc Oxide particles. The filter selected was from The Lührfilter DF Range of Filters, using a Compressed Air Online Cleaning System. The Filter Type chosen was a DF 3.0/2/2.3/80/24. This unit was fitted with 384 off horizontal filter bags, manufactured from Polyester Needlefelt, each 2.3m long, which provided a total filtration area of 339m2.

 The complete scope of supply included the filter unit, complete with a pyramid hopper and double flap discharge valve, support structure, access and platforms, together with the  extraction and clean gas ductwork. The filter was delivered to site fully assembled, including the trace heating of the hopper and thermal insulation. Lührfilter also supplied a direct coupled fan set complete with a 37.0 kW motor and a discharge silencer to achieve the specified sound pressure limit of 85 dB(A) @ 1 metre. A lime injection system was also incorporated into the design, which comprised a storage / discharge hopper, metered screw feeder, conveying fan and flexible delivery hose.

 The complete system was controlled and monitored by a Lührfilter PLC, specifically designed and manufactured for the project, which included a frequency inverter for fan control and a touch-screen HMI. The whole filter package was installed and fully commissioned both electrically and mechanically by UK Based Lührfilter Site Engineers.

The installed plant performance was far better than the levels stipulated in the contract, with particulate emissions considerably lower than the limit of 10 mg/Nm3.