Automation of an air-screen seed cleaner

• US 4,991,721 A
• Filed: 08/15/1988
• Issued: 02/12/1991
• Est. Priority Date: 08/15/1988
• Status: Expired due to Fees

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Misra, Manjit K., Shyy, Yuh-Yuan
• Primary Examiner(s): Focarino, Margaret A.
• Assistant Examiner(s): WACYRA, EDWARD MICHAEL
• Application Number:
  US07/231,946
• Time in Patent Office: 911 Days
• Field of Search: 209/21, 209/30-37, 209/44.1, 209/44.2, 209/134-139.1, 209/146, 209/147, 209/149, 209/153, 209/154, 209/237, 209/238, 209/255, 209/257, 209/546, 209/549 , 209/552, 209/555, 209/557, 209/629, 209/639, 55/215, 55/218, 55/270, 55/279, 55/413, 55/423-426, 364/500, 364/502, 364/552, 364/555, 406/28, 406/168, 406/169, 406/173
• US Class Current: 209/31
• CPC Class Codes: B07B 11/04 Control arrangements
• CPC Class Codes: B07B 11/06 Feeding or discharging arrangements
• CPC Class Codes: B07B 4/02 while the mixtures fall
• CPC Class Codes: B07B 4/08 while the mixtures are supported by sieves, screens, or like mechanical elements
• CPC Class Codes: B07B 9/00 Combinations of apparatus for screening or sifting or for separating solids from solids using gas currents; General arrangement of plant, e.g. flow sheets

Abstract

A cleaning system is provided for separating desired material from undesirable material in a mixture of particulate materials. The system includes an inlet for receiving the mixture of materials and an outlet for discharging the desired materials. At least one screen is provided for separating undersized material from oversized material within the mixture, and at least one vacuum air-lift is provided for separating the lighter material from the heavier material within the mixture. A first sensor is mounted below the discharge end of the screen for sensing the quantity of undersized material separated by the screen and a second sensor is mounted in the air-lift for sensing the quantity of lighter materials separated by the air-lift. The signals generated by the sensors can be received by a processing unit which adjusts the extent of separation by the screen and by the air-lift to achieve the desired efficiency of the cleaning system.

Claims

1. An improved cleaning system for separating lighter material from heavier material in a mixture of particulate materials, the system including an inlet for receiving the mixture, an outlet for discharging heavier material, and a vacuum air-lift means between the inlet and the outlet for separating the lighter material from the heavier material, the air-lift means having a spout for collecting the lighter material and having a first gate movable between a normal closed position for maintaining the vacuum of the air-lift means and a second open position for discharging the lighter material, the improvement comprising:

a second gate in said air-lift spout mounted upstream from the first gate and being movable between a normal open position when the first gate is closed and a closed position when the first gate is open; and

a sensor for sensing the quantity of lighter material separated by the air-lift means, the sensor being mounted in the spout downstream from the second gate so that when the second gate is in the open position, the lighter material separated by the air-lift means enters the spout and passes the second gate for sensing by the sensor.

2. The cleaning system of claim 1 wherein the second gate is pivotally mounted in the spout so as to automatically move to the closed position by the vacuum of the air-lift means when the first gate is open.

3. The cleaning system of claim 1 wherein the sensor produces signals corresponding to the quantity of lighter material sensed by the sensor, and the sensor is interfaced with a processing means for receiving and processing the signals for monitoring the cleaning system and for adjusting the extent of separation by the air-lift means to achieve a desired efficiency of the system.

4. The cleaning system of claim 1 further comprising at least one elongated screen for separating undersized material from oversized material, the screen having a feed end and a discharge end, and a screening spout adjacent the discharge end for collecting the undersized material sifted through the screen,

a divider plate mounted in the screening spout so as to divide the screening spout into an upstream side and a downstream side, the upstream side collecting the undersized material sifted along the substantial length of the screen and the downstream side collecting the undersized material sifted immediately adjacent the discharge end of the screen, whereby the presence of undersized material in the downstream side of the screening spout indicates that the separation by the screen of the undersized material from the oversized material is incomplete;

and

another sensor mounted in the downstream side of the screening spout for sensing the quantity of undersized material collected therein.

5. The cleaning system of claim 4 wherein the another sensor produces signals corresponding to the quantity of undersized material sensed by the another sensor and the another sensor is interfaced with a processing means for receiving and processing the signals for monitoring the cleaning system and for adjusting the extent of separation by the screen to achieve a desired efficiency of the system.

6. A method for separating desire material from undesirable material in a mixture of particulate materials, comprising:

introducing the mixture onto a first screen means for separating undersized material from oversized material within the mixture, the screen means having a feed end and a discharge end;

sensing the quantity of undersized material separated by the screen means adjacent the discharge end thereof and generating a signal corresponding to such quantity;

depositing the oversized material into an air-lift means for separating lighter material from heavier materials within the oversized materials;

sensing the quantity of lighter materials separated by the air-lift means and generating a signal corresponding to such quantity;

adjusting the extent of separation by the screen means and the extent of separation by the air-lift means in response to the respective generated signals so as to achieve a desired cleaning efficiency; and

sampling the separated lighter materials to determine the quality thereof.

7. The method of claim 6 wherein the adjustments are made by a processing unit which receives and processes the respective signals.

8. The method of claim 6 further comprises dividing the discharge end of the screen means into an upstream side and a downstream side, the sensing of the quantity of undersized materials occurring only on the downstream side of the discharge end of the screen means.

9. The method of claim 6 wherein the sampling further includes opening a first gate and closing a second gate within said air-lift means so as to maintain the vacuum therein, the sample being located between the first and second gates.

10. The method of claim 9 wherein the closing of the second gate is automatic and simultaneous with the opening of the first gate.

11. The method of claim 6 further comprising receiving any of said generated signals with a processing means.

12. The method of claim 11 further comprising presenting a user of the method with official information from said processing means regarding and corresponding to the generated signals.

13. The method of claim 11 further comprising interpreting the generated signals with the processing means and instructing a user how to adjust any of the introduction and separation of material to cause the method to achieve desired separation of undesirable material from desirable material.

14. The method of claim 11 further comprising automatically adjusting with the processing means any of the introduction and separation of material on a continuous, automatic basis to achieve pre-set separation of undesirable material from desirable material.

15. The method of claim 11 further comprising controlling operation of one or more motors in response to the generated signals.

16. A method of separating an undesired portion from a desired portion of a mixture of various size, shape and weight materials, comprising the steps of:

feeding material into a separator means at a first rate of feed;

separating at least some of the undesirable portion of the material from the desirable portion of material in the separator means;

sensing the quantity of undesirable material which is separated from the desirable material in the separator means;

adjusting at least one of the set of feed rate of the material and separation of the material to change the separation process; and

sampling the separated undesirable portion of materials to determine the quality thereof.