Board maker gets unstuck
1 Oct 2007
Europe's leading manufacturer of particle board Pfleiderer has overcome production issues at its Gravejo, Poland plant, which had required it to frequently replace high-pressure pumps on its production lines.
At Gravejo, the pumps deliver resinous glue to a mixing chamber, where it is sprayed on to wood fibres in the early stages of chipboard manufacture. The originally installed gear pumps, which were chosen for their high pressure capability, were required to pump the resin at 80 bar pressure to the spray nozzles.
Pfleiderer experienced particular problems with mechanical seals, which began to leak. Moreover the pumps were not easy to clean. Particles of hardened resin became trapped between closely meshing gears and damaged them. The pump and gearbox on one system had to be replaced three times within months.
There was no confidence that other gear pumps or piston-type pumps would do better, so pump specialists Verder Polska suggested a seal-less, positive displacement pump — a Hydra-Cell from Wanner, which could operate continuously at the pressures required. Working at 80 bar, and driven by 18.5 kW motors, the new pumps deliver resin to the spray bars at 100 litres/min.
The drive mechanism on the Wanner pump is isolated from the pumped liquid by flexible hydraulically balanced diaphragms, which also perform the pumping action. This avoids problems with seal leakage or hardened resin. The pump can handle abrasives and solid particles, chemicals, corrosives, viscous liquids and thin non-lubricating fluids and can run dry without damage.
Pfleiderer has subsequently installed smaller Hydra-Cell pumps to replace a larger, more expensive piston diaphragm pump on a system, pumping ammonia nitrate. On this application the pumps delivered the required flow smoothly, with lower pulsation than the original pump.
Until recently, Scotland's Belhaven Brewery — which was founded by Benedictine monks back in 1415 — operated a CIP (Clean in Place) system employing an AOD (air-operated diaphragm) pump to scavenge cleaning solution from bright beer holding tanks via a flow plate to the CIP feed tank during the routine cleaning process.
However, the AOD pump struggled with drawing the solution from the outer tanks - some of which were more than 20 metres away - and would frequently become air locked and fail to empty the tanks satisfactorily. The system was also noisy and exerted a lot of vibration and stress on the pipe work installation, so increasing operating and maintenance costs.
For effective CIP, liquid levels must be kept low to ensure complete cleaning of the tanks. This, however, often leads to vortexing and air entrainment in the CIP solution, a common problem faced by CIP scavenge pumps.
To overcome these problems, the brewery installed a self-priming, liquid ring pump, designed specifically for scavenge applications. The pump — a Grundfos Sipla 28.1 Bloc Super — was selected for its suction capacity and ability to pump entrained air without air locking.
The top casing connections of the Sipla model are designed to ensure liquid is retained in the housing whilst the pump is stationary, to ensure the pump is primed ready for re start. Since installation, the pump has serviced all the tanks, including evacuating the CIP solution from over 20m of 3" diameter suction pipe from the furthest vessels.
"We have seen improvements in; scavenge ability, shorter CIP times, reduced costs, improved tank cleaning, lower noise levels, less vibration, pipe work stresses and lower life cycle costs," said Ronnie Muir, engineering manager for Belhaven Brewery.
At Gravejo, the pumps deliver resinous glue to a mixing chamber, where it is sprayed on to wood fibres in the early stages of chipboard manufacture. The originally installed gear pumps, which were chosen for their high pressure capability, were required to pump the resin at 80 bar pressure to the spray nozzles.
Pfleiderer experienced particular problems with mechanical seals, which began to leak. Moreover the pumps were not easy to clean. Particles of hardened resin became trapped between closely meshing gears and damaged them. The pump and gearbox on one system had to be replaced three times within months.
There was no confidence that other gear pumps or piston-type pumps would do better, so pump specialists Verder Polska suggested a seal-less, positive displacement pump — a Hydra-Cell from Wanner, which could operate continuously at the pressures required. Working at 80 bar, and driven by 18.5 kW motors, the new pumps deliver resin to the spray bars at 100 litres/min.
The drive mechanism on the Wanner pump is isolated from the pumped liquid by flexible hydraulically balanced diaphragms, which also perform the pumping action. This avoids problems with seal leakage or hardened resin. The pump can handle abrasives and solid particles, chemicals, corrosives, viscous liquids and thin non-lubricating fluids and can run dry without damage.
Pfleiderer has subsequently installed smaller Hydra-Cell pumps to replace a larger, more expensive piston diaphragm pump on a system, pumping ammonia nitrate. On this application the pumps delivered the required flow smoothly, with lower pulsation than the original pump.
Until recently, Scotland's Belhaven Brewery — which was founded by Benedictine monks back in 1415 — operated a CIP (Clean in Place) system employing an AOD (air-operated diaphragm) pump to scavenge cleaning solution from bright beer holding tanks via a flow plate to the CIP feed tank during the routine cleaning process.
However, the AOD pump struggled with drawing the solution from the outer tanks - some of which were more than 20 metres away - and would frequently become air locked and fail to empty the tanks satisfactorily. The system was also noisy and exerted a lot of vibration and stress on the pipe work installation, so increasing operating and maintenance costs.
For effective CIP, liquid levels must be kept low to ensure complete cleaning of the tanks. This, however, often leads to vortexing and air entrainment in the CIP solution, a common problem faced by CIP scavenge pumps.
To overcome these problems, the brewery installed a self-priming, liquid ring pump, designed specifically for scavenge applications. The pump — a Grundfos Sipla 28.1 Bloc Super — was selected for its suction capacity and ability to pump entrained air without air locking.
The top casing connections of the Sipla model are designed to ensure liquid is retained in the housing whilst the pump is stationary, to ensure the pump is primed ready for re start. Since installation, the pump has serviced all the tanks, including evacuating the CIP solution from over 20m of 3" diameter suction pipe from the furthest vessels.
"We have seen improvements in; scavenge ability, shorter CIP times, reduced costs, improved tank cleaning, lower noise levels, less vibration, pipe work stresses and lower life cycle costs," said Ronnie Muir, engineering manager for Belhaven Brewery.
