Chopper pumps stop for nothing
Chris French speaks to Landia’s Hugh Vaughan about the crucial role played by chopper pumps in pulp and paper manufacture.
In theory, the occasional halt to raise, repair and clean a faulty pump might not sound like a major crisis, but if the recent innovation of chopper pumps can help ensure non-stop production, why continue to specify pumps that are prone to breakdown?
According to Landia, a family run company that is shortly set to celebrate 70 years in business, chopper pumps armed with heat-treated steel knives are a truly no-nonsense solution. Available in cast iron and stainless steel AISI 316 (suitable for applications with considerable pH variations) they include:
- Dry installed pumps
- Long shaft wet-well pumps
- Submersible pumps
"We’ve increasingly learned how crucial pump reliability is to the paper industry," says Hugh Vaughan from Landia. "It might seem unrealistic to expect a pump to simply keep on going and going. However, a suitably vicious chopper pump can handle all kinds of applications, from the pumping of mediums containing wood and bark, or wastewater with paper and plastics, to actual repulping of rejects." Highly efficient
‘Vicious’ is an apt description. Chopper pumps are equipped with a highly efficient knife system containing two rotating knives on the pump shaft, and up to three fixed knives at the pump inlet. Even for the harshest of paper processing applications, the knives not surprisingly comminute any impurities into small manageable particles before they have entered the pump, successfully preventing blockages to pipes or the pump itself. It is argued by Landia that a design that does not use hydraulics (the impeller and the front plate) for the cutting process should be favoured by those seeking added reliability.
"It is fair to say that pumps in paper mills are never located in the most accessible places," says Vaughan. "This is all the more reason to opt for long term reliability from a good quality pump, because frequent repairs to an unsuitable unit creates unnecessary and very unwelcome downtime."Production process
"Chopper pumps are so strong and reliable," enthuses Vaughan, "that they are not just used as part of the water and waste treatment set-up, they’re becoming part of the actual paper production process. They can break up almost anything that’s thrown at them."
For certain paper types, tests carried out in conjunction with leading European paper mills have shown that by using chopper pumps for repulping of rejects, a quality of paper comparable with that of new from traditional pulpers can be achieved.
Vaughan continued: "As more companies look to reduce their downtime and maintenance costs, it is more important than ever to ensure a smooth running production line.
"Of course you have to invest, but the calculation of a frequently interrupted production line versus the cost of a new chopper pump will show only one winner."