Sludge flow measuring system

Abstract

A system for the transport of high solids sludge includes a positive displacement pump for pumping sludge through a pipeline. The volume of sludge transported is accurately measured by determining the fill percentage by using a material flow signal, measured time intervals, hydraulic fluid pressure, or hydraulic fluid flow rate during each pumping cycle.

What is claimed is: 
     
       1. A pump system for pumping a sludge material, the pump system comprising: a positive displacement pump which includes: an inlet for receiving sludge material which contains solids, liquids, and gases and which is partially compressible;   an outlet at which sludge material is delivered under pressure;   a first cylinder;   a first piston movable in the first cylinder;   first hydraulic drive means for moving the first piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   first valve means for connecting the first cylinder to the outlet during the pumping stroke and connecting the first cylinder to the inlet during the filling stroke;     means for providing a first signal which indicates when sludge material begins to flow from the first cylinder at a time following the beginning of piston movement during the pumping stroke; and   means for determining volume of sludge material delivered at the outlet during the pumping stroke based upon the first signal.   
     
     
       2. The pump system of claim 1 wherein the means for determining comprises: means for measuring time intervals from start of the pumping stroke to occurrence of the first signal and from occurrence of the first signal to end of the pumping stroke; and   means for calculating volume based upon the time intervals.   
     
     
       3. The pump system of claim .[.and.]. .Iadd.1 .Iaddend.further comprising.[.:.]. means for sensing position of the first piston in the first cylinder; and   wherein the means for determining calculates the volume based upon the sensed position of the first piston when the first signal occurs.   
     
     
       4. The pump system of claim 1 wherein the first valve means is of a type which connects the first cylinder to the outlet only when pressure within the first cylinder essentially equals pressure at the outlet, and wherein the means for providing a first signal senses when the first valve means connect the first cylinder to the outlet. 
     
     
       5. The pump system of claim 4 wherein the first valve means includes: an inlet poppet valve connected between the inlet and the first cylinder; and   an outlet poppet valve connected between the outlet and the first cylinder.   
     
     
       6. The pump system of claim 5 wherein the first valve means further includes: valve control means for controlling operation of the inlet and outlet poppet valves to cause both the inlet and outlet poppet valves to be closed at the beginning of each stroke.   
     
     
       7. The pump system of claim .Iadd.1 .Iaddend.wherein the positive displacement pump further includes: a second cylinder;   a second piston movable in the second cylinder;   second hydraulic drive means for moving the second piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   second valve means for connecting the second cylinder to the outlet during the pumping stroke and connecting the second cylinder to the inlet during the filling stroke.   
     
     
       8. The pump system of claim 7 wherein the means for providing a first signal also provides the first signal to indicate when sludge material begins to flow from the second cylinder during the pumping stroke. 
     
     
       9. The pump system of claim 1 and further comprising: means for measuring time during pumping strokes; and   means for determining a volume flow rate as a function of the volume of sludge material delivered at the outlet during a pumping stroke and the measured time.   
     
     
       10. The pump system of claim 1 and further comprising: means for determining a total accumulated volume based upon the volumes determined during a plurality of pumping strokes.   
     
     
       11. A pump system of claim 10 and further comprising: means for measuring time during the plurality of pumping strokes; and   means for determining an average pumping rate as a function of the total accumulated volume and the measured time.   
     
     
       12. A pump system for pumping a material, the pump system comprising: a positive displacement pump which includes: an inlet;   an outlet;   a first cylinder;   a first piston movable in the first cylinder;   first hydraulic drive means for moving the first piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   first valve means for connecting the first cylinder to the outlet during the pumping stroke and connecting the first cylinder to the inlet during the filling stroke;     means for providing a first signal which indicates when material begins to flow from the first cylinder at a time following the beginning of piston movement during the pumping stroke, the means for providing a first signal comprising: means for sensing hydraulic fluid pressure;   means for sensing pressure of the material at the outlet; and   means for producing the first signal when the hydraulic fluid pressure sensed and the pressure of the material sensed have a predetermined relationship; and     means for determining volume of material delivered during the pumping stroke based upon the first signal.   
     
     
       13. A pump system for pumping a material, the pump system comprising: a positive displacement pump which includes: an inlet;   an outlet;   a first cylinder;   a first piston movable in the first cylinder;   first hydraulic drive means for moving the first piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   first valve means for connecting the first cylinder to the outlet during the pumping stroke and connecting the first cylinder to the inlet during the filling stroke;     means for providing a first signal which indicates when material begins to flow from the first cylinder at a time following the beginning of piston movement during the pumping stroke;   means for determining volume of material delivered at the outlet during the pumping stroke based upon the first signal; and   means for sensing hydraulic fluid flow rate in the first hydraulic drive means;   wherein the means for determining volume further bases the volume on sensed hydraulic fluid flow rate.   
     
     
       14. A pump system for pumping a sludge material, the pump system comprising: a positive displacement pump which includes: an inlet for receiving sludge material which contains solids, liquids, and gases and which is partially compressible;   an outlet at which sludge material is delivered under pressure;   a cylinder;   a piston movable in the cylinder;   hydraulic drive means for moving the piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   valve means for connecting the cylinder to the outlet during the pumping stroke and connecting the cylinder to the inlet during the filling stroke;     means for sensing a parameter related to operation of the pump and which is related to a fill percentage of sludge material in the cylinder during each pumping stroke; and   means for providing a signal representative of volume of sludge material delivered at the outlet during each pumping stroke based upon the sensed parameter.   
     
     
       15. A pump system for pumping a material, the pump system comprising: a positive displacement pump which includes: an inlet;   an outlet;   a cylinder;   a piston movable in the cylinder;   hydraulic drive means for moving the piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   valve means for connecting the cylinder to the outlet during the pumping stroke only when pressure within the cylinder exceeds pressure at the outlet, and for connecting the cylinder to the inlet during the filling stroke;     means for sensing when the valve means connects the cylinder to the outlet; and means for providing a signal representative of volume of material delivered at the outlet during each pumping stroke based upon the sensed time when the valve means connects the cylinder to the outlet.     
     
     
       16. A method of determining volume of sludge material delivered by a positive displacement piston/cylinder pump, the method comprising: sensing a fill percentage of the cylinder based upon when sludge material, which contains solids, liquids, and gases and which is partially compressible, begins to flow out of the cylinder during each pumping stroke of the pump after piston movement begins; and   determining actual volume delivered during each pumping stroke based on the fill percentage of the cylinder when sludge material begins to flow out of the cylinder after piston movement begins.   
     
     
       17. A pump system for pumping a sludge material, the pump system comprising: a positive displacement pump which includes: an inlet for receiving sludge material which contains solids, liquids, and gases and which is partially compressible;   an outlet at which sludge material is delivered under pressure;   a cylinder;   a piston movable in the cylinder;   hydraulic means for moving the piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   valve means for connecting the cylinder to the outlet during the pumping stroke when pressure within the cylinder essentially equals the pressure at the outlet;     means for providing a signal which indicates when the valve means connects the cylinder to the outlet; and   means for determining volume of sludge material delivered at the outlet during the pumping stroke based upon the signal.   
     
     
       18. The pump system of claim 17 wherein the valve means includes: an inlet poppet valve connected between the inlet and the cylinder; and   an outlet poppet valve connected between the outlet and the cylinder.   
     
     
       19. The pump system of claim 18 wherein the valve means further includes: valve control means for controlling operation of the inlet and outlet poppet valves to cause both the inlet and outlet poppet values to be closed at the beginning of each stroke.   
     
     
       20. A pump system for pumping a material, the pump system comprising: a positive displacement pump which includes: an inlet;   an outlet;   a first cylinder;   a first piston movable in the first cylinder;   first hydraulic drive means for moving the first piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   first valve means for connecting the first cylinder to the outlet during the pumping stroke and connecting the first cylinder to the inlet during the filling stroke;     means for sensing hydraulic fluid pressure;   means for producing a first signal when the hydraulic fluid pressure sensed and the pressure of the material sensed have a predetermined relationship; and   means for determining volume of viscous material delivered at the outlet during the pumping stroke based upon the first signal.   
     
     
       21. The pump system of claim 20 wherein the positive displacement pump further includes: a second cylinder;   a second piston movable in the second cylinder;   second hydraulic drive means for moving the second piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   second valve means for connecting the second cylinder to the outlet during the pumping stroke and connecting the second cylinder to the inlet during the filling stroke.   
     
     
       22. A pump system for pumping a material, the pump system comprising: a positive displacement pump which includes: an inlet;   an outlet;   a first cylinder;   a first piston movable in the first cylinder;   first hydraulic drive .[.mans.]. .Iadd.means .Iaddend.for moving the first piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   first valve means for connecting the first cylinder to the outlet during the pumping stroke and connecting the first cylinder to the inlet during the filling stroke;     means for sensing hydraulic fluid flow rate in the first hydraulic drive means; and   means for determining volume of viscous material delivered at the outlet during the pumping stroke based on sensed hydraulic fluid flow rate.   
     
     
       23. The pump system of claim 22 and further comprising: means for determining a total accumulated volume based upon the volume determined during a plurality of pumping strokes.   
     
     
       24. The pump system of claim 23 and further comprising: means for measuring time during the plurality of pumping strokes; and   means for determining an average pumping rate as a function of the total accumulated volume in the measured time.   
     
     
       25. The pump system of claim 22 and further comprising: means for measuring time during pumping strokes; and   means for determining a volume flow rate as a function of the volume of viscous material delivered at the outlet during a pumping stroke in the measured time.   
     
     
       26. A method of determining a volume of a sludge material delivered by a positive displacement piston/cylinder pump, the method comprising: sensing when, during each pumping stroke of the pump, the sludge material, which contains solids, liquids, and gases and which is partially compressible, begins to flow out of the cylinder during each pumping stroke of the pump after piston movement begins; and   determining actual volume delivered during each pumping stroke based on when during the pumping stroke sludge material begins to flow out of the cylinder after piston movement begins.   
     
     
       27. A method of determining volume of sludge material delivered by a positive displacement piston/cylinder pump, the method comprising: sensing hydraulic fluid pressure;   sensing the pressure of the sludge material, which contains solids, liquids, and gases and which is partially compressible;   producing a signal when the sensed hydraulic fluid pressure and the sensed sludge material pressure have a predetermined relationship; and   determining the volume of sludge material delivered during the pumping stroke based upon the signal.   
     
     
       28. A method of determining volume of compressible material delivered by a positive displacement piston/cylinder pump, the method comprising; sensing hydraulic fluid flow rate in a hydraulic drive means; and   determining the volume of compressible material delivered during the pumping stroke based on the sensed hydraulic fluid flow rate.   
     
     
       29. A method of determining volume of sludge material delivered by positive displacement system/cylinder pump, the method comprising: measuring time intervals from start of the pumping stroke to a moment when sludge material, which contains solids, liquids, and gases and which is partially compressible, begins to flow from the cylinder at a time following the beginning of the piston movement during the pumping stroke;   measuring time intervals from a moment when sludge material begins to flow from the cylinder at a time following the beginning of the piston movement during the pumping stroke to the end of the pumping stroke; and   calculating volume based upon the measured time intervals.   
     
     
       30. The method of claim 29 and further comprising: determining a total accumulated volume based upon the volumes determined during a plurality of pumping strokes.   
     
     
       31. The method of claim 30 and further comprising: measuring time during the plurality of pumping strokes; and   determining an average pumping rate as a function of the total accumulated volume and the measured time.   
     
     
       32. A pump system for pumping a sludge material, the pump system comprising: a positive displacement pump which includes: an inlet for receiving sludge material which contains solids, liquids, and gases and which is partially compressible;   an outlet at which sludge material is delivered under pressure;   a cylinder;   a piston movable in the cylinder;   hydraulic drive means for moving the piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   valve means for connecting the cylinder to the outlet during the pumping stroke and connecting the cylinder to the inlet during the filling stroke;     means for providing a signal which indicates when sludge material begins to flow from the cylinder at a time following the beginning of the piston movement during the pumping stroke; means for measuring time intervals from start of the pumping stroke to occurrence of the signal and from occurrence of the signal to end of the pumping stroke; and     means for calculating volume of sludge material delivered during the pumping stroke based upon the time intervals.   
     
     
       33. A pump system for pumping sludge material, the pump system comprising: a positive displacement pump which includes: an inlet for receiving sludge material which contains solids, liquids, and gases and which is partially compressible such that a reduction in volume of sludge material occurs when sludge material is placed under pressure in the pump system;   an outlet at which sludge material is delivered under pressure;   a cylinder;   a piston movable in the cylinder;   hydraulic drive means for moving the piston reciprocatively through a cycle which includes a pumping stroke and a filling stroke; and   valve means for connecting the cylinder to the outlet during the pumping stroke and connecting the cylinder to the inlet during the filling stroke;     means for providing a signal which indicates when sludge material begins to flow from the cylinder at a time following the beginning of the piston movement during the pumping stroke; and   means for determining volume of sludge delivered at the outlet during the pumping stroke based upon the signal.   
     
     
       34. A method of determining volume of sludge material delivered by a positive displacement piston/cylinder pump having an inlet and an outlet, the sludge material received at the inlet being partially compressible such that a reduction in volume of the sludge material occurs during each pumping stroke, the method comprising: sensing when during each pumping stroke of the pump, the sludge material begins to flow out of the cylinder during each pumping stroke from the pump after piston movement begins; and   determining actual volume delivered during each pumping stroke based on when, during the pumping stroke, sludge begins to flow out of the cylinder after piston movement begins.