Brochure

In a continuous digester’s cooking zone, cooking liquors are circulated in loops to add the appropriate heat and chemicals to cook the wood
chips. Valves control the circulating liquor as it travels from the screens lining the interior of the digester, to the circulation pump, through
the heat exchanger, and returns the liquor to the digester cooking zone. This application generally consists of two loops, one for both the
upper and lower cooking zones.
Switching valves are also commonly found in the digester’s extraction or wash zone. Here, wash filtrate is added to the bottom of the
digester with counter-current flow to the chip mass. As the wash fluid extracts the used cooking liquors, valves remove the wash fluid for
further processing.
These valves frequently see high cycling, high temperatures, high pressures, and corrosive chemicals.
Digester Switching
12 | Fisher
®
Pulp and Paper Solutions
Cooking
Product Solutions
n EXTENDED SERVICE LIFE PTFE packing and heavy duty valve bearings extend service life capabilities.
n ZERO LOST MOTION Splined shaft and taper pin/disk connections provide tight control.
n INCREASED FLOW CAPACITY Contoured disk increases ow capacity while reducing operating torque.
n EMISSION CONTROL Superior sealing and ENVIRO-SEAL
™
packing reduces emissions.
n EASY INSTALLATION Centering holes and line ange bolts reduces valve centering issues for easy installation.
Fisher DSV High Performance Eccentric Disk Digester Switching Valve with 1061 actuator
Cooking