Automatic frequency controlled motor backdrive
First Claim
Patent Images
1. A centrifuge comprising:
- a) a horizontal rotatable bowl;
b) an axially positioned rotatable screw with flights there along cooperatively positioned in said bowl to enable solid and liquid separation of a slurry placed in said bowl so that solid and liquid streams are discharged from said bowl;
c) a gear box having a powered input for a gear box drive motor; and
connecting between said bowl and said screw to enable;
1) said bowl and said screw to rotate about a common axis in a common direction; and
2) at a speed difference determined by the gear box;
d) a gear box drive motor control system connected to said gear box drive motor for control of said gear box drive motor between specified maximum and minimum speeds to enable said gear box to vary the speed difference between said bowl and screw speeds;
e) wherein said gear box drive motor control system reduces the speed difference between said bowl and said screw speeds to a selected speed difference;
f) wherein said gear box drive motor control system comprises;
1) a variable frequency generator means connected to said drive motor;
2) means for measuring said drive motor operation to monitor operation of said device motor during operation and forming an indication of drive motor operation; and
3) means responsive to said measuring means to change the frequency of said frequency generator means in response to measurements thereby.
2 Assignments
0 Petitions
Accused Products
Abstract
In a horizontal centrifuge, a bowl rotates in the same direction as a screw internally of the bowl. The bowl and screw connect to a three input gear box which rotates the bowl and screw at a small differential, or the scrolling rate. A separate motor running at a variable rate connects to the third gear box input and thereby reduces the scrolling rate. A feedback loop connects to the motor to vary the motor speed so that the scrolling rate is varied. A maindrive motor rotates the bowl which then couples through the gear box to rotate the screw and thereby furnish the power to rotate the bowl and screw.
61 Citations
26 Claims
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1. A centrifuge comprising:
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a) a horizontal rotatable bowl; b) an axially positioned rotatable screw with flights there along cooperatively positioned in said bowl to enable solid and liquid separation of a slurry placed in said bowl so that solid and liquid streams are discharged from said bowl; c) a gear box having a powered input for a gear box drive motor; and
connecting between said bowl and said screw to enable;1) said bowl and said screw to rotate about a common axis in a common direction; and 2) at a speed difference determined by the gear box; d) a gear box drive motor control system connected to said gear box drive motor for control of said gear box drive motor between specified maximum and minimum speeds to enable said gear box to vary the speed difference between said bowl and screw speeds; e) wherein said gear box drive motor control system reduces the speed difference between said bowl and said screw speeds to a selected speed difference; f) wherein said gear box drive motor control system comprises; 1) a variable frequency generator means connected to said drive motor; 2) means for measuring said drive motor operation to monitor operation of said device motor during operation and forming an indication of drive motor operation; and 3) means responsive to said measuring means to change the frequency of said frequency generator means in response to measurements thereby. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of controlling the operation of a horizontal centrifuge to vary the separation of solid and liquid materials from a slurry comprising the steps of:
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a) rotating a bowl around a screw with flights where both said bowl and screw rotate in a common direction; b) connecting said bowl and said screw with a gear box to rotate at a speed difference defining a scrolling rate so that a slurry in said bowl is interacted with said bowl and screw flights to direct separated solid and liquid materials to spaced solid and liquid material output means for discharging solid and liquid material; and c) wherein said gear box has a gear box input connected to a gear box motor to enable operation at a scrolling rate determined by said gear box motor, and including the step of changing gear box motor at least partially in response to gear box torque to reduce the scrolling rate. - View Dependent Claims (13)
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14. A centrifuge attachment to enable control of the scrolling rate of a screw positioned in a surrounding bowl wherein the bowl and screw are rotationally connected together by a gear box having an input and the gear box varies the scrolling rate dependent on the input thereto, and wherein a main motor provides power for rotation of the centrifuge to separate one material from another, the attachment comprising:
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a) a gear box motor connected to the gear box to vary the scrolling rate between the screw and bowl; b) motor controller connected to said gear box motor to provide variable control of the gear box motor so that the gear box motor is varied in operation to enable the gear box motor to vary the scrolling rate between the bowl and screw; and c) wherein said gear box drive motor rotates at a speed dependent on a frequency input thereto, and said motor controller provides the variable frequency input so that said controller changes the gear box motor speed. - View Dependent Claims (15)
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16. A centrifuge comprising:
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a) a horizontal rotatable bowl; b) an axially positioned rotatable screw with flights there along cooperatively positioned in said bowl to enable solid and liquid separation of a slurry placed in said bowl so that solid and liquid streams are discharged from said bowl; c) a gear box having a powered input for a gear box motor and connecting between said bowl and said screw to enable; 1) said bowl and said screw to rotate about a common axis in a common direction; and 2) at a speed difference determined by the gear box; d) a gear box drive motor control system for control of said gear box drive motor between specified maximum and minimum speeds to enable said gear box to vary the speed difference between said bowl and screw speeds; e) wherein said gear box drive motor control system reduces the speed difference between said bowl and said screw speeds to a selected speed difference; and f) wherein said bowl and said screw are driven directly by a main drive motor connecting to said bowl and said screw to enable said main drive motor to provide power for rotation of both said bowl and said screw, and said gear box provides a gear box determined difference in speed of said bowl and said screw in the absence of a gear box drive motor input to said gear box. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification