Double diffuser with backflush pistons

Pulp treating apparatus comprising:

• a generally upright vessel defining an interior volume containing pulp;
• liquid conduit means mounted in said vessel;
• and
• liquid pumping means located within said vessel and comprising first and second cylinders having first and second ends, respectively, said first end of said first cylinder in open communication with pulp in the interior volume of the vessel, and said second end of said first cylinder and said first and second ends of said second cylinder in open communication with liquid in said liquid conduit;
• first and second liquid pistons within said first and second cylinders, respectively, for relative reciprocal movement;
• and means for effecting relative movement between said pistons and cylinders to cause said pistons to force liquid out of said cylinders and into the liquid conduits in one direction of relative movement, and to take the liquid into the cylinders from the liquid conduit means in another direction of relative movement.

Pulp treating apparatus comprising

• a generally upright vessel defining an interior volume containing pulp;
• liquid conduit means mounted in said vessel;
• a first cylinder open at its first end to the pulp in the vessel, and at its second end to the liquid in the conduit means;
• a second cylinder open at both the first and second ends thereof to the liquid in said conduit means;
• a first piston, with piston rod, mounted in said first cylinder;
• and a second piston, with piston rod, mounted in said second cylinder;
• and
• means for effecting relative reciprocation between said pistons and cylinders.

A pulp treating apparatus comprising:

• a generally upright vessel defining an interior volume containing pulp to be treated;
• a pulp inlet to the vessel;
• a pulp outlet from the vessel, the pulp flowing generally vertically between teh inlet and the outlet;
• a plurality of screens mounted within the vessel;
• said screens including a first set of screens supported by a plurality of supporting arms, and extending above the arms;
• and a second set of screens extending above the first set of screens;
• first extraction means for extracting liquid through the first set of screens;
• second extracting means, independent of said first extraction means, for extracting liquid through the second st of screens;
• first and second screen backflushing means for respectively flushing each of said first and second set of screens, each of said backflushing means mounted within the vessel and including a chamber defining element having first and second ends, the first end in open communication with liquid in said supporting arms, and the second end in operative with the pulp within the interior volume of the vessel;
• a liquid engaging element mounted within said chamber defining element for relative reciprocal movement between said liquid engaging element and said chamber defining element;
• and means for effecting relative movement between said chamber defining element and said liquid engaging element to cause said liquid engaging element to force liquid out of the chamber in one direction of relative movement between said elements, to effect backflushing, and take liquid into the chamber in another direction of relative movement therebetween;
• and
• first and second sets of nozzles for introducing treatment liquid into the vessel, said first set of nozzles having a liquid introducing portion thereof terminating adjacent said first set of screens, and said second set of nozzles having a liquid introducing portion thereof terminating adjacent said second set of screens;
• said first and second sets of nozzles connected to a common rotating element at the top of said vessel.

A pulp treating apparatus comprising:

• a generally upright vessel defining an interior volume containing pulp to be treated;
• a pulp inlet to the vessel;
• a pulp outlet from the vessel, the pulp flowing generally vertically between the inlet and the outlet;
• a plurality of screens mounted within the vessel;
• said screens including a first set of screens supported by a plurality of supporting arms, and extending above the arms;
• and a second set of screens extending above the first set of screens;
• first extraction means for extracting liquid through the first set of screens, comprising a first supporting arm;
• second extracting means, independent of said first extraction means, for extracting liquid through the second set of screens, comprising a second supporting arm;
• first and second screen backflushing means for respectively flushing each of said first and second set of screens, each of said backflushing means mounted within the vessel and including a chamber defining element having first and second ends, the first end in open communication with liquid in said supporting arms, and the second end in operative communication wit the pulp within the interior volume of the vessel;
• a liquid engaging element mounted within said chamber defining element for relative reciprocal movement between said liquid engaging element and said chamber defining element;
• and means for effecting relative movement between said chamber defining element and said liquid engaging element to cause said liquid engaging element to force liquid out of the chamber in one direction of relative movement between said elements, to effect backflushing, and take liquid into the chamber in another direction of relative movement therebetween;
• and
• wherein said second extraction means also comprises internal funnel means extending in said first screens, and having a portion in fluid engagement with the sides of a said supporting arms.

A pulp treating apparatus comprising:

• a generally upright vessel defining an interior volume containing pulp to be treated;
• a pulp inlet to the vessel;
• a pulp outlet from the vessel, the pulp flowing generally
• a plurality of screens mounted within the vessel;
• said screens including a first set of screens supported by a plurality of supporting arms, and extending above the arms;
• and a second set of screens extending above the first set of screens;
• first extraction means for extracting liquid through the first set of screens;
• second extracting means, independent of said first extracting means, for extracting liquid through the second set of screens;
• first and second screen backflushing means for respectively flushing each of said first and second set of screens, each of said backflushing means mounted within the vessel and including a chamber defining element having first and second ends, the first end in open communication with liquid in said supporting arms, and the second end in operative communication with the pulp within the interior volume of the vessel;
• a liquid engaging element mounted within said chamber defining element for relative reciprocal movement between said liquid engaging element and said chamber defining element;
• and means for effecting relative movement between said chamber defining element and said liquid engaging element to cause said liquid engaging element to force liquid out of the chamber in one direction of relative movement between said elements, to effect backflushing, and take liquid into the chamber in another direction of relative movement therebetween;
• and
• means for effecting vertical movement of said screens and supporting arms in the direction of pulp movement at a first speed, and in the direction opposite to pulp movement at a second speed much faster than said first speed, and wherein said means for effecting vertical movement of said screens and supporting arms comprises fluid cylinder means mounted below said supporting arms and exteriorly of the vessel.