Peristaltic pump for pumping ink or cleaning fluids in a printing machine

Pump means for pumping ink to and from a printing section of a printing machine, comprising:

• a housing means;
• a first rotatable pump element within said housing means for pumping said ink to an inlet means in said printing section at a first volumetric flow rate, said first rotatable pump element including:
• a first rotor means having at least two equally radially-spaced lobes thereon in operative engagement with a first flexible tube means for confining a first finite quantity of said ink between two portions of said tube means compressed by succeeding pairs of said lobes during rotation of said rotor means for moving said first finite quantity of said ink from an inlet end to an outlet end of said first flexible tube means;
• a second rotatable pump element within said housing means for pumping an excess of said ink from a first outlet means in said printing section at a second volumetric flow rate less than said first volumetric flow rate;
• and
• a third rotatable pump element within said housing means for pumping an excess of said ink from a second outlet means in said printing section at a third volumetric flow rate less than said first volumetric flow rate, the volumetric flow rate of said second and third volumetric flow rates combined exceeding said first volumetric flow rate,
• said second and third rotatable pump elements each including:
• a second rotor means having at least three equally radially-spaced lobes thereon in operative engagement with a second flexible tube means for confining a second finite quantity of said excess ink between two portions of said second tube means compressed by succeeding pairs of said lobes during rotation of said second rotor means for moving said second finite quantity of said excess ink from an inlet end to an outlet end of said second flexible tube means.

First pump means for pumping a different color ink to each of several sections of a printing machine comprising:

• a housing means;
• a first rotatable pump element within said housing means for each of said printing sections for pumping a selected color of said ink to a corresponding printing section to which each of said first rotatable pump means is operably connected;
• each of said first rotatable pump elements including,
• a flexible tube means positioned against a curved portion of said housing means for carrying said ink from a first end of said tube means to a second end of said tube means,
• a rotor means having at least two equally radially-spaced lobes thereon with each of said lobes coming successively into contact with said tube means during rotation of said rotor means with successive pairs of said lobes being operative to press two portions of said tube means against said curved portion of said housing means to confine a finite volume of said ink in said tube means,
• said rotor means operatively moving successive ones of said finite volume of said ink from said first end of said tube means to said second end of said tube means to provide a substantially constant flow of said ink therein;
• a second pump means for pumping an excess of said ink from each of said several printing sections;
• a second housing means;
• and
• a second rotatable pump element within said second housing means for each of said several printing sections for pumping said excess ink from an outlet means in each of said printing sections to which said second rotatable pump element is associated.

Pump means for pumping ink to and from a printing section of a printing machine wherein said printing section includes a closed-chamber doctor blade means having an inlet means for receiving said ink, a first outlet means for discharging an excess of said ink and, a second outlet means above said first outlet means for discharging said excess of said ink, said pump means comprising:

• a housing means;
• a first rotatable pump element within said housing means for pumping said ink to said inlet means at a first volumetric flow rate;
• a second rotatable pump element within said housing means for pumping said excess of said ink from said first outlet means at a second volumetric flow rate less than said first volumetric flow rate;
• and
• a third rotatable pump element within said housing means for pumping said excess of said ink from said second outlet means at a third volumetric flow rate less than said first volumetric flow rate when said ink in said closed-chamber doctor blade means rises to the height of said second outlet means, the volumetric flow rate of said second and third flow volumetric flow rates combined exceeding said first volumetric flow rate for preventing a positive pressure of said ink in said closed-chamber doctor blade means.