Sealless diaphragm pumps allow
Rapid payback on burner feeder lines

Some six years ago, engineers at a process plant in Sweden were confronted with frequent breakdowns of their piston pumps, feeding turpentine and pitch oil to burner units. They replaced the piston pumps with diaphragm pumps and now report on the results.

Arizona Chemical produces resins and fatty acids from the ‘black liquor’ which is a by-product of pulp manufacture in the Swedish paper industry. By-products of the plant’s own process include turpentine, which is used in-house for heating, and pitch oil, which is sold back to the mills. Neither of these products is a good lubricant and their extremely low lubricity makes them difficult to handle.

Sealless diaphragm pump
The piston-type pumps originally used at the plant for this work frequently broke down through severe wear. "We had to rebuild our old piston pumps five to ten times a year," said one engineer. "Maintenance costs were high and the pumps were unreliable." When pump specialists AB Telfa visited the plant they agreed with Arizona Chemical about the low lubricity of the media, and noted that the pitch oil also had an ash content of up to 0.4%, which would intensify the wear problem. But they felt that piston pumps were not ideal for this type of application. Telfa recommended a sealless diaphragm pump, whose design allows frictionless operation and enables all parts in contact with the media to work without lubrication.

Three month trial
A three-month trial on one turpentine burner went so well that three more diaphragm pumps were fitted on burners and another, to replace the piston pump, on the pitch oil line. Four years later, not a single pump breakdown had been reported on any of these lines, and the customer was able to confirm that the pump investment had paid for itself within the first year. The annual savings in pump maintenance costs were estimated afterwards at 18.000 euro. All the units are still working reliably.
Telfa say that they have successfully installed similar pumps on a number of sites with similar needs, and point out other features of the range which have come into play here and elsewhere. These include low energy consumption, ability to work without fine filtration, simple maintenance and compact dimensions.
Hydra-Cell pumps (ranging up to 128l/min max flow and 170 bar working pressure) are marketed throughout Europe with technical support through the Wanner distribution network. <<