Piston Pump for Thick Substances

Abstract

The invention relates to a piston pump for thick matter, in particular for high-solids sewage sludge, coal sludge and concrete. The piston pump has at least one delivery cylinder ( 16 ) which contains a motor-driven or hydraulically driven delivery piston ( 20 ) and which has an orifice ( 12 ) which communicates alternately with the interior of a material feed container ( 10 ) and with a pressure delivery line ( 30 ) in a slide-controlled manner in accordance with the movement of the delivery piston ( 20 ). In order to significantly increase the degree of filling of the at least one delivery cylinder ( 16 ), an annular nozzle ( 32 ) opening into the delivery cylinder ( 16 ) in the region of the orifice ( 12 ) is provided, and this annular nozzle ( 32 ) is connected to an external pressure line ( 34 ) to which a lubricant can be admitted.

1 - 18 . (canceled) 
   
   
       19 . Piston pump for thick substances, having at least one feed cylinder ( 16 ) containing a motor-driven or hydraulically driven feed piston ( 20 ), which cylinder has an orifice opening ( 12 ) that alternately communicates with the interior of a material application container ( 10 ) and with a pressure feed line (pressure connector  30 ), as determined by the movement of the feed piston ( 20 ), controlled by a slide, wherein a ring nozzle ( 32 ) that opens into the feed cylinder ( 16 ) is disposed in the region of the orifice opening ( 12 ), which nozzle is connected with at least one external pressure line ( 34 ), that the pressure line ( 34 ) can have a lubricant applied to it by way of a high-pressure pump, and is connected with a ring channel ( 38 ) that opens into the ring nozzle ( 32 ), and wherein the feed cylinder ( 16 ) carries an outer ring body ( 42 ), which has at least one bore ( 36 ) connected with the pressure line ( 34 ) on the outside, having a ring channel ( 38 ) that leads to the ring nozzle ( 32 ). 
   
   
       20 . Piston pump according to  claim 19 , wherein the ring channel ( 38 ) is delimited on the inside by an outer surface of the feed cylinder, or of an inner pipe ( 40 ) that follows it axially, and on the outside by an inner surface of the outer ring body ( 42 ). 
   
   
       21 . Piston pump according to  claim 19 , wherein an inner pipe ( 40 ) follows the feed cylinder ( 16 ), on the face side, which pipe engages into a recess of the outer ring body ( 42 ) that is open towards the inside, and delimits the ring channel ( 38 ) and the ring nozzle ( 32 ) together with this ring body. 
   
   
       22 . Piston pump according to  claim 19 , wherein the ring channel ( 38 ) has at least one ring-shaped cross-section widening ( 50 ). 
   
   
       23 . Piston pump according to  claim 22 , wherein the ring channel ( 38 ) has two ring-shaped cross-section widenings ( 50 ), spaced at a distance from one another. 
   
   
       24 . Piston pump according to  claim 19 , further comprising a control device that responds to the position and/or the stroke direction of the feed piston ( 20 ) in the feed cylinder ( 16 ), and a control valve that responds to an output signal of the control device and is disposed in the pressure line ( 34 ). 
   
   
       25 . Piston pump according to  claim 24 , wherein the control valve disposed in the pressure line ( 34 ) opens during the suction stroke of the feed piston ( 20 ) and closes before its pressure stroke. 
   
   
       26 . Piston pump according to  claim 24 , wherein the control valve is configured as a directional valve that can be controlled by way of the feed piston ( 20 ), preferably magnetically. 
   
   
       27 . Piston pump according to  claim 19 , wherein two feed cylinders ( 16 ), which each have a ring nozzle ( 32 ) in their orifice region ( 12 ), are provided, whose ring nozzles ( 32 ) can have lubricant applied to them, by way of the control valve, during every suction stroke of the feed piston ( 20 ), which can be controlled in opposite cycles. 
   
   
       28 . Piston pump according to  claim 19 , wherein the inner pipe ( 40 ) is braced between two ring surfaces ( 46 ,  48 ) of the feed cylinder ( 16 ) and of the outer ring body ( 42 ) that face one another, with a rear, radially projecting collar ( 44 ). 
   
   
       29 . Method for operation of a piston pump for thick substances, in which thick-substance material is alternately drawn into a feed cylinder ( 16 ) that is open on one side, during a suction stroke, and pressed out of the feed cylinder into a pressure feed line during a subsequent pressure stroke, wherein lubricant is injected into the feed cylinder ( 16 ) during every suction stroke, whereby the lubricant is injected over the entire circumference of the feed cylinder inner surface into the separation region between thick-substance material and feed cylinder inner surface. 
   
   
       30 . Method according to  claim 29 , wherein the lubricant injection is interrupted during the pressure stroke.