Slurry pump control system

• US 6,595,829 B1
• Filed: 02/05/2001
• Issued: 07/22/2003
• Est. Priority Date: 02/09/1999
• Status: Expired due to Fees

• Current Assignee: Revasum, Inc.
• Original Assignee: Stragbaugh
• Inventors: Melcer, Chris
• Primary Examiner(s): Eley, Timothy V.
• Application Number:
  US09/777,501
• Time in Patent Office: 897 Days
• Field of Search: 451/5, 451/8, 451/36, 451/41, 451/60, 451/67, 451/99, 451/446, 137/2, 137/12, 137/551, 222/71
• US Class Current: 451/5
• CPC Class Codes: B24B 37/04 designed for working plane surfaces
• CPC Class Codes: B24B 49/10 involving electrical means B24B49/02, B24B49/08 take precedence
• CPC Class Codes: B24B 57/02 for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents
• CPC Class Codes: Y10T 137/0379 By fluid pressure

Abstract

A CMP slurry pumping system and method which uses the slurry pump inlet pressure as input to the pump controller, and the controller adjusts pump speed to account for variations in inlet pressure.

Claims

1. A system for pumping slurry from a slurry source to a slurry output, said system comprising:

a peristaltic pump having an inlet and an outlet;

a slurry supply line communicating with the inlet of the pump;

a slurry output line in fluid communication with the outlet of the pump, wherein said output line provides slurry to the slurry output;

a pressure sensor, operably connected to the slurry supply line, for sensing the pressure in the supply line; and

a controller operatively connected to the pump and the pressure sensor, said controller being programmed to receive input regarding the pressure sensed by the pressure sensor, to accept input regarding the desired flow rate, and to calculate the pump speed required to provide the desired flow rate based on the pressure in the supply line, and maintain the pump speed at the calculated pump speed.

2. The system of claim 1 wherein the pressure sensor is a non-intrusive pressure sensor which senses pressure in the slurry supply line without placing any structure in the slurry flow.

3. The system of claim 1 wherein the controller is programmed to calculate the pump speed required to provide the desired flow rate based on the equation RPM=M×

FLOWRATE, where RPM is the pump speed, M is the pump speed proportionality constant and FLOW RATE is the desired flow rate.

4. The system of claim 3 wherein the pump speed proportionality constant M is calculated based on the equation M=slope(inlet pressure)+c, where the value of the slope and c in the equation are empirically determined through testing of the system and where inlet pressure is the pressure sensed by the pressure sensor.

5. A method for pumping slurry comprising:

pumping the slurry from a slurry source through a supply line to a slurry output using a peristaltic pump;

sensing the pressure in the supply line;

determining a desired flow rate of slurry;

calculating a pump speed required to provide the desired flow rate based on the pressure in the supply line; and

operating the pump at the calculated pump speed.

6. The method of claim 5 wherein the calculating step calculates the pump speed required to provide the desired flow rate based on the equation RPM=M×

FLOWRATE, where RPM is the pump speed, M is-the pump speed proportionality constant and FLOW RATE is the desired flow rate.

7. The method of claim 6 wherein the pump speed proportionality constant M is calculated based on the equation M=slope(inlet pressure)+c, where the value of the slope and c in the equation are empirically determined and where inlet pressure is the pressure sensed in the supply line.