Chlorine Dioxide Addition

After digestion, end products that are required to be whitened are bleached using chlorine dioxide which preserves pulp strength and provides stable brightness. Modern mills typically have pulp stock enter the oxygen delignification stage before the medium consistency pulp heads to the conventional bleaching sequence. These can vary from four to six separate stages depending on the end-user’s requirements. A standard mill would utilize a DEOPDED sequence, or an alternating sequence of chlorine dioxide (D), alkaline extraction stages (E), oxygen (O), and peroxide (P) brightening stage. This alternating sequence of chlorine dioxide and alkaline helps to break down the increasingly smaller amounts of residual lignin. This valve is subjected to high corrosion due to the chlorine dioxide material, and accurate control is necessary because of the high costs of chemicals.

Fisher’s V150 Vee-Ball® provides maximum flow control and a modified equal percent characteristic.


  • Long life service
  • Low friction
  • Reduced maintenance
  • Alloy valve capabilities available for high corrosion applications
The Vee-Ball valve combines globe valve ruggedness with the efficiency of a rotary valve. A shearing action between the V-notch ball and the ball seal promotes smooth, non-clogging operation. The unrestricted straight-through flow design provides high capacity for gas, steam, liquids, and fibrous slurries.
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