Pulp pump

Abstract

Centrifugal pumps for pumping a pulp suspension and conducting gas away from the pulp suspension are disclosed including a pump housing having an inlet and an outlet, a rotary shaft, an impeller mounted on the rotary shaft within the pump housing, the impeller including a hub and pump blades extending outwardly from the hub, a wheel disk adjacent to the impeller so that the pump blades extend outwardly along the wheel disk, a vacuum impeller within the pump housing behind the wheel disk and including a vacuum pump housing, vacuum impeller blades, a seal for sealing the vacuum pump housing to the rotary shaft, the vacuum pump housing including a suction port for drawing gas into the vacuum pump housing and an exhaust port for expelling gas therefrom.

1 - 3 . (canceled).  
   
   
       4 . A centrifugal pump for pumping a pulp suspension and conducting gas away from said pulp suspension, said centrifugal pump comprising a pump housing including an inlet for said pulp suspension and an outlet for said pumped pulp suspension, a rotary shaft, an impeller mounted on said rotary shaft within said pump housing, said impeller including a hub, and a plurality of pump blades extending outwardly from said hub, a wheel disk adjacent to said impeller whereby said pump blades extend outwardly along said wheel disk, a vacuum impeller disposed within said pump housing behind said wheel disk, said vacuum impeller including a vacuum pump housing, a plurality of vacuum impeller blades disposed within said vacuum pump housing, and a seal for sealing said vacuum pump housing to said rotary shaft, said vacuum pump housing including a suction port for drawing gas into said vacuum pump housing and an exhaust port for expelling gas from said vacuum pump housing.  
   
   
       5 . The centrifugal pump of  claim 4  including a channel connecting said suction port with said exhaust port, and a valve disposed within said channel for controlling the vacuum in said vacuum pump housing.  
   
   
       6 . The centrifugal pump of  claim 4  wherein said vacuum pump housing includes a first side adjacent to said impeller and a second side distal from said impeller, said suction port and said exhaust port being disposed on said first side of said vacuum pump housing, said seal being disposed on said second side of said vacuum pump housing and including a sealed housing and a liquid inlet connected to said sealed housing, said sealed housing communicating with said vacuum pump housing to supply said liquid to said vacuum pump housing.