Method and apparatus for controlling vertical and horizontal basket centrifuges

• US 6,063,292 A
• Filed: 06/03/1998
• Issued: 05/16/2000
• Est. Priority Date: 07/18/1997
• Status: Expired due to Fees

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Leung, Wallace Woon-Fong
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/090,132
• Time in Patent Office: 713 Days
• Field of Search: 210/85, 210/86, 210/93, 210/94, 210/96.1, 210/143, 210/360.1, 210/739, 210/740, 210/745, 210/746, 210/770, 210/781, 210/787, 210/87, 210/141, 210/380.1, 494/1, 494/7, 494/210, 494/37, 250/339.1, 177/1, 177/2, 177/25.11, 177/245
• US Class Current: 210/739
• CPC Class Codes: B04B 11/043 Load indication with or without control arrangements
• CPC Class Codes: B04B 13/00 Control arrangements specially designed for centrifuges; Programme control of centrifuges control arrangements for feed, charge, or discharge B04B11/00

Abstract

A computerized system for monitoring, diagnosing, operating, and controlling various parameters and processes of basket centrifuges is presented. The computer control system actuates at least one of a plurality of control devices based on input from one or more monitoring sensors so as to provide real time, continuous, operational control of certain parameters. In a preferred embodiment, the apparatus comprises a basket centrifuge with at least one sensor for providing input which is analyzed to provide information regarding cake moisture at a given time. As a result of the analysis, at least one output may be generated to activate a control device that effects changes or adjustments in the operation of the centrifuge.

Claims

1. A method for controlling a basket centrifuge having a rotatable perforated basket, rotatable about an axis, the basket having a generally cylindrical inner side wall and radially inwardly extending end walls defining a generally annular chamber for receiving slurry to be separated, the method comprising:

delivering a quantity of slurry of liquid and solid particles into the chamber in the basket;

rotating the basket through a separation cycle to separate the slurry into a liquid phase passing outwardly through the basket and a cake of solids built up on the inner wall;

directing energy outwardly toward the cake from a source which is out of contact with the slurry, and sensing energy reflected back from the cake to monitor the monitoring cake moisture level during the separating cycle; and

adjusting controlling the operation of the centrifuge based on the cake moisture level.

2. The method in accordance with claim 1, wherein

the surface cake moisture is measured in-situ using infrared reflection from the cake inside the basket.

3. The method in accordance with claim 2, wherein

the cake moisture level is measured by an infra-red source and pickup which are mounted on a traveller which transverses along the axis of the basket during monitoring.

4. The method of claim 1, wherein:

the surface cake moisture is monitored at a series of positions along the longitudinal length of the basket.

5. A basket centrifuge rotatable, for controlled separation of slurry into a liquid phase and a solid phase, the centrifuge comprising:

a basket having a generally cylindrical permeable inner side wall and radially inwardly extending end walls defining a generally annular chamber for receiving a quantity of slurry to be separated, with the basket being rotatably mounted for rotation about an axis and rotatable through a separation cycle to separate the slurry into a liquid phase passing through the basket and a cake of solids built up on the inner side of the basket;

a cake moisture monitor in the basket spaced radially inwardly of the annular chamber and out of contact with the slurry and cake in the chamber, the monitor comprising a source of energy directed outwardly toward the cake and a sensor sensing energy reflected back from the cake with the reflected energy being indicative of the moisture level of the cake exposed to the energy; and

a controller receiving signals from the monitor and controlling one or more control devices associated with the centrifuge in response to the cake moisture level.

6. The basket centrifuge of claim 5, further comprising a traveler carrying the monitor and moveably mounted for movement through a range of positions along a line generally parallel to the axis of rotation of the basket.

7. The basket centrifuge of claim 5 wherein the cake moisture

monitor comprises an infrared source and a sensor.

8. A basket centrifuge having a perforated basket rotatable about its axis, comprising

a sensor for sensing during the feed cycle, both the quantity of flow and the solids content of the slurry from which the total dry solids loading to the basket can be derived, and

at least one weighing device for measuring the wet cake mass in the basket during a separation cycle in real time from which the cake moisture fraction of the wet cake can be deduced in real time during the separation cycle.

9. The basket of claim 8 wherein the flow of the slurry is measured by the volumetric flow rate of the slurry.

10. The basket of claim 8 wherein the flow rate of the slurry is measured by the mass flow rate of the slurry.

11. The basket of claim 8 wherein the weighing device is a calibrated load cell.

12. A method for using a basket centrifuge comprising a basket having a generally cylindrical permeable inner side wall and radially inwardly extending end walls defining a generally annular chamber for receiving a quantity of slurry to be separated with the basket being rotated in a separation cycle to form a layer of cake solids in the basket, the method comprising:

delivering a quantity of slurry of liquid phase and solid particles;

measuring the liquid and solid content of the quantity of the slurry delivered to the basket;

measuring the weight of the slurry in the basket after at least a portion of the separation cycle;

calculating the moisture level of the layer of cake solids; and

controlling the operation of the centrifuge based on the calculated moisture level.

13. A method for using the basket centrifuge in accordance with claim 12 including:

stopping the separation cycle and advancing to a cake discharge cycle when the calculated moisture level meets a predetermined moisture content.

14. A method for controlling a basket centrifuge having a perforated basket rotatable about an axis, the basket having a generally cylindrical inner side wall and radially inwardly extending end walls defining a generally annular chamber for receiving slurry to be separated, the method comprising:

delivering a quantity of slurry of liquid and solid particles into the chamber in the basket;

rotating the basket through a separation cycle to separate the slurry into a liquid phase passing through the basket and a cake of solids built up on the inner side of the basket;

discharging cake from the basket;

monitoring the cake moisture level of the discharged cake; and

controlling the operation of the centrifuge in separating a subsequent quantity of slurry based at least in part on the cake moisture level of the cake previously discharged.

15. The method of claim 14, wherein:

infra-red energy is directed toward the cake and the energy reflected back form the cake is sensed to sense the cake moisture level.