Pump apparatus and method for continuously conveying a viscous material

Abstract

A pump apparatus includes at least two main delivery cylinders, a delivery pipeline for conducting viscous material in a flow direction, and a switchable gate mechanism which is moveable between a first position to establish a connection between an outlet port of a first one of the delivery cylinders and the delivery pipeline, and a second position to establish a connection between an outlet port of a second one of the delivery cylinders and the delivery pipeline. Disposed downstream of the gate mechanism is a compensating cylinder having an outlet port for discharge of viscous material into a section of the delivery pipeline. A shut-off valve is disposed in the delivery pipeline in flow direction upstream of the outlet port of the compensating cylinder and constructed in the form of a two-port rotary gate valve.

1 . A pump apparatus for conveying a viscous material, comprising: 
 at least two main delivery cylinders for conveying viscous material;    a delivery pipeline for conducting the viscous material in a flow direction;    a switchable gate mechanism moveable between a first position to establish a connection between an outlet port of a first one of the delivery cylinders and the delivery pipeline, and a second position to establish a connection between an outlet port of a second one of the delivery cylinders and the delivery pipeline;    a compensating cylinder disposed downstream of the gate mechanism and having an outlet port for discharge of viscous material into a section of the delivery pipeline; and    a shut-off valve disposed in the delivery pipeline in flow direction upstream of the outlet port of the compensating cylinder, said shut-off valve being constructed in the form of a two-port rotary gate valve.    
   
   
       2 . The pump apparatus of  claim 1 , wherein the shut-off valve is disposed in flow direction downstream of the gate mechanism.  
   
   
       3 . The pump apparatus of  claim 1 , further comprising a reservoir, wherein the gate mechanism is constructed to connect the second delivery cylinder with the reservoir, when assuming the first position, and to connect the first delivery cylinder with the reservoir, when assuming the second position.  
   
   
       4 . The pump apparatus of  claim 1 , wherein the gate mechanism has a self-adjusting ring in an area of its inlet port for connection to the outlet ports of the first and second delivery cylinders.  
   
   
       5 . The pump apparatus of  claim 1 , wherein the shut-off valve has a casing and a valve body, said casing having an area disposed in surrounding relationship to a first port of the shut-off valve and constructed to have a spherical shape, wherein the valve body is swingable about a pivot axis and constructed to have a zone of spherical shape complementing the spherical shape of the casing area.  
   
   
       6 . The pump apparatus of  claim 5 , further comprising a self-adjusting ring in surrounding relationship to the port of the shut-off valve.  
   
   
       7 . The pump apparatus of  claim 6 , wherein the self-adjusting ring has a surface in confronting relationship to the valve body, said surface of the self-adjusting ring having a zone of spherical shape.  
   
   
       8 . The pump apparatus of  claim 5 , wherein the casing and the valve body are flattened in a plane perpendicular to the pivot axis.  
   
   
       9 . The pump apparatus of  claim 1 , wherein the compensating cylinder includes a displaceable pipe bend which forms part of the delivery pipeline and is constructed to increase or decrease a volume of the delivery pipeline in dependence on an adjustment of the pipe bend.  
   
   
       10 . The pump apparatus of  claim 9 , wherein the pipe bend is curved by 180°.  
   
   
       11 . The pump apparatus of  claim 9 , wherein the pipe bend has an upstream inlet port which embraces an upstream part of the delivery pipeline, and a downstream outlet port which is embraced by a downstream part of the delivery pipeline.  
   
   
       12 . The pump apparatus of  claim 1 , wherein the main delivery cylinders are arranged in inclined relationship to a horizontal.  
   
   
       13 . The pump apparatus of  claim 1 , further comprising a common control circuit for controlling the operation of the main delivery cylinders, the gate mechanism, and the shut-off valve.  
   
   
       14 . A method of conveying a viscous material, comprising the steps of: 
 pumping viscous material during a pump stroke from a main delivery cylinder to a delivery pipeline in a first switching mode, while a compensating cylinder executes an intake stroke to receive viscous material;    closing a shut-off valve disposed in the delivery pipeline in flow direction upstream of an outlet port of the compensating cylinder after conclusion of the pump stroke by the main delivery cylinder; and    initiating an intake stroke by the main delivery cylinder in a second switching mode only after the shut-off valve has been closed.    
   
   
       15 . The method of  claim 14 , further comprising the step of switching a gate mechanism to implement the first and second switching modes, wherein a switching from the first switching mode to the second switching mode commences only after the intake stroke by the main delivery cylinder has started.  
   
   
       16 . The method of  claim 15 , wherein the gate mechanism is operated to interact with two of said main delivery cylinder, and further comprising the step of operating the two main delivery cylinders in opposite mode between the first and second switching modes.  
   
   
       17 . The method of  claim 15 , further comprising the step of reducing a pressure of a working fluid of the main delivery cylinder during switching operation of the gate mechanism.  
   
   
       18 . The method of  claim 14 , further comprising the step of increasing a pressure of viscous material conducted upstream of the shut-off valve before opening the shut-off valve.  
   
   
       19 . The method of  claim 18 , wherein the pressure is increased to a pressure level corresponding to a pressure of viscous material conducted downstream of the shut-off valve.  
   
   
       20 . A pump apparatus for conveying a viscous material, comprising: 
 at least two main delivery cylinders for conveying a viscous material;    a delivery pipeline for conducting the viscous material in a flow direction;    a switchable gate mechanism moveable between a first position to establish a connection between an outlet port of a first one of the delivery cylinders and the delivery pipeline, and a second position to establish a connection between an outlet port of a second one of the delivery cylinders and the delivery pipeline;    a compensating cylinder disposed downstream of the gate mechanism and having an outlet port for discharge of viscous material into a section of the delivery pipeline, said compensating cylinder having a displaceable pipe bend which forms part of the delivery pipeline and is constructed to increase or decrease a volume of the delivery pipeline in dependence on an adjustment of the pipe bend; and    a shut-off valve disposed in the delivery pipeline in flow direction upstream of the outlet port of the compensating cylinder.    
   
   
       21 . The pump apparatus of  claim 20 , wherein the pipe bend is curved by 180°.  
   
   
       22 . The pump apparatus of  claim 20 , wherein the pipe bend has an upstream inlet port which embraces an upstream part of the delivery pipeline, and a downstream outlet port which is embraced by a downstream part of the delivery pipeline.