Rotor wear eliminated with pump

The Beetham, Cumbria plant of BillerudKorsnäs in the UK has replaced a progressive cavity (PC) pump with APEX10 hose pump technology from Watson-Marlow Pumps Group on an application dosing abrasive pigment in kraft paper manufacture.

The move has solved the problem of stator and rotor wear on the PC pump that was leading to a drop in performance, downtime, and the need for regular maintenance.

At Beetham, kraft paper is produced in quantities of around 34,000 tonnes-a-year across three shifts by 140 people. In an application involving the dosing of pigment into paper stock, the plant was experiencing difficulty with its PC pump.

“We put the pigment into the stock preparation end of the paper machine to introduce a colour shade to certain grades,” says engineering manager Tony Halhead. “We dose very low, precise volumes as the shade is critical. However, the abrasive nature of the pigment was causing the stators and rotors in our 1-inch PC pump to wear, leading to a drop in performance.”

As a result, the engineering team at Beetham would have to speed up the three-phase inverter in the control box to maintain f low rates at the required levels, causing even faster wearing. However, if the drop in performance went unnoticed, it could lead to a variation in shade and to rejected paper. On a long production run this could be very expensive.

“We were experiencing dips in performance on a regular basis so we decided to address the situation, particularly when also considering the downtime and maintenance issues,” says Halhead. “Other Watson-Marlow pumps were being used on site successfully so we thought they would be a natural first port of call.”

Watson-Marlow recommended the use of an APEX10 hose pump. APEX pumps are engineered for maximum uptime and process continuity. Through design attributes such as heat dissipation, precision machined hose elements and optimised hose compression, APEX pumps reduce hose element fatigue compared to other hose pumps and when a hose replacement is required, this is a quick task which can be carried out in-situ by maintenance staff.

The benefit for APEX users such BillerudKorsnäs is reduced maintenance intervals, leading to decreased cost of ownership. Operating and inventory costs are also less, as a single hose element is all that needs to be replaced.

BillerudKorsnäs installed two APEX10 models in February 2014, one duty and one standby. The pumps are fixed to a mobile skid and piped with valves to speed changeover. Offering a 14 rpm, 0.18kW motor suitable for VSD control, the f low rate is 25-30 litre/hr when using a green pigment, and 10-15 litre/hr for a blue pigment. The pumps are f looded suction (600mm head into pump via 2.5 metres of 1/2” f lexi hose). Discharge is via 18 metres of 1/2” f lexi hose inclusive of an 8.5 metre lift into the paper stock tank.

“Since installation the APEX10 pumps have been running reliably in a 24/7 operation,” says Mr Halhead. “We are now considering the replacement of other PC pumps on site with APEX models.”

Contact: 09 273 3166 or email: enquiries@ wmbpumps.co.nz