Digester Sumps

Digesters break down wood chips into pulp using heat, pressure, and chemicals such as sodium hydroxide and sodium sulfide. Digester sumps collect residual slurry, wash water, and fibers from the process for recirculation, cleaning, or disposal. Maintaining flow from these sumps is essential to prevent downtime and ensure stable pulp production.

Challenges:
The slurry in digester sumps is hot, fibrous, and chemically aggressive. Fibers tend to bind and form mats that clog conventional pumps, while high temperatures and caustic chemicals accelerate corrosion and seal degradation. Downtime for cleaning or repairs can disrupt continuous operations and reduce plant efficiency.

Solution:
Hevvy/Toyo pumps are purpose-built to handle hot, fibrous, and caustic slurries. Their recessed impellers and agitator options prevent fiber buildup and maintain consistent flow, even with high solids content. Available in stainless steel and elastomer-lined configurations, they resist corrosion and provide long service life under the extreme conditions found in digester sumps.