Cross filters prevent unscheduled shutdowns at paper mill

John Morfield has installed automatic filters at one of the UK’s largest paper mills to protect against the risk of expen-sive pump failures due to poor quality water.

The mill had recently been modified and expanded introducing state of the art plant and machinery including new pulp mill pumps that use water to lubricate the mechanical seals. The pumps are protected against a contaminated water sup-ply by flow switches, which automatically shut down the plant if they begin to register a blockage. It soon became apparent that this plant demanded a higher quality of water that could be guaranteed from the mill’s river water source.

Although the mill has always treated the incoming water, this was found to be in-sufficient to prevent the pulp mill from shutting down as a result of blockages which had a knock-on effect on the operation of the rest of the mill. If the mill has an unscheduled shutdown because of the seal water it could result in blockages that may take several hours to clear and cost many thousands of pounds in the event of the board machines being forced to shut down. It is also vital that the mechanical pumps have water to lubricate the seals, since just 60 seconds without it can ruin them.

John Morfield engineers introduced a solution to this expensive and disruptive problem. They recommended the installation of Cross automatic filtration equipment which would permanently remove the contamination without interrupting the water supply.

Cross filters utilise specially designed zero gravity filter coils which use a pressure differential or time lapse signal to backwash to a completely clean condition. The Cross Phoenix filter units each comprise six coils which are individually and sequentially backwashed with no interruption to flow through the filter. Three filters rated at 50 microns have been installed to protect the pulp mill providing the additional capacity

The introduction of this filter system swiftly benefitted the operation of the mill and the success in avoiding unscheduled shutdowns at the mill has recouped the £20,000 cost of installation in only a few months.