The original tangential nozzle utilized in digester blow tanks had not changed in design for nearly one hundred years until my father, Les Sanderson (a British trained mechanical engineer employed by Crown Zellerbach in the 1970’s), was tasked with reducing the expensive annual cost of repairing damaged nozzles and blow tank walls. Damage to the blow tank was occurring with the release of energy as the pulp exited the nozzle and struck the walls, which was significantly exacerbated with low quality chips.
Les believed the original tangential nozzles (TN) design was flawed as it didn’t account for the change in thermal dynamics of the pulp as it entered the blow tank. This realization resulted in Les creating a re-designed nozzle that significantly reduced blow tank maintenance costs, which currently remains the mainstay of continuous maintenance programs globally.
By changing the location how the pulp entered the blow tank and projecting the pulp away from the tank wall on entry, allowed the pressure on the wall to be significantly reduced when the pulp finally made contact. An analogy of this principle is found in the sand blasting process, where to be effective the blasting nozzle must be 3” or 4” away from its target. If the nozzle was moved much further away, the force/effectiveness of the blasting process would be decreased.
In the 40 years since the introduction of the Sanderson Nozzles, we are proud to say they are now installed globally in over 30 facilities with more than 100 nozzles supplied to nearly every major global corporation in the pulp and paper business. The Sanderson Nozzles are utilized with hardwood and softwood process as well as in containerboard and pulp production facilities.
Les Sanderson believed that an engineer should design something to last, and with the Sanderson Nozzle, he achieved his goal. However, the best testimonial for performance and savings are the facilities who have saved millions of dollars in maintenance costs because they installed long-lasting Sanderson Nozzles.