Method of varying the speed of a center pivot irrigation system

• US 6,036,121 A
• Filed: 09/14/1998
• Issued: 03/14/2000
• Est. Priority Date: 09/14/1998
• Status: Expired due to Term

• Current Assignee: Valmont Industries Incorporated
• Original Assignee: Valmont Industries Incorporated
• Inventors: Gerdes, Jerry D.
• Primary Examiner(s): Douglas, Steven O.
• Assistant Examiner(s): HUYNH, KHOA D
• Application Number:
  US09/152,335
• Time in Patent Office: 547 Days
• Field of Search: 239/1, 239/11, 239/727, 239/728, 239/729
• US Class Current: 239/728
• CPC Class Codes: A01G 25/162 Sequential operation

Abstract

The method of controlling the speed of the last regular drive unit of a center pivot irrigation system having a corner irrigation system pivotally connected thereto is disclosed comprising the steps of: placing a pressure transducer at the downstream side of the main water line for monitoring the changes in main water line pressure as the sprinklers on the extension water line are sequenced; driving the last regular drive unit at a predetermined speed; recording the output of the pressure transducer at predetermined intervals; comparing the recorded output at the predetermined intervals to the pressure recorded when all the sprinklers on the extension line are turned off; and varying the speed of the last regular drive unit according to the formula NEW SPEED=(END PRESSURE/RETRACTED END PRESSURE)^1/2 ×L.R.D.U. SPEED SETTING.

Claims

1. The method of controlling the speed of the last regular drive unit (L.R.D.U.) of a center pivot irrigation system having a corner irrigation system pivotally connected thereto which is movable out into the corners of a field to irrigate the same, said center pivot irrigation system including a main water line, having sprinklers provided thereon, supported by a plurality of spaced-apart drive units, said corner irrigation system including an extension water boom having sequenced sprinklers thereon, comprising the steps of:

placing a pressure transducer at the downstream side of said main water line for monitoring the changes in main line water pressure as the sprinklers on said extension water line are sequenced;

driving the L.R.D.U. at a predetermined speed (L.R.D.U. speed setting);

recording the output of said pressure transducer (end pressure) at predetermined intervals;

comparing the said recorded output (end pressure) at said predetermined intervals to the pressure recorded when all the sprinklers on said extension line are turned off (retracted end pressure);

and varying the speed of said L.R.D.U. approximately according to the formula;

NEW SPEED=(END PRESSURE/RETRACTED END PRESSURE)^1/2 ×

L.R.D.U. SPEED SETTING.

2. The method of claim 1 wherein said predetermined intervals are increments in time.

3. The method of claim 1 wherein said speed of said L.R.D.U. is continuously varied.

4. The method of controlling the speed of the last regular drive unit (L.R.D.U.) of a center pivot irrigation system having a corner irrigation system pivotally connected thereto which is movable out into the corners of a field to irrigate the same, said center pivot irrigation system including a main water line, having sprinklers provided thereon, supported by a plurality of spaced-apart drive units, said corner irrigation system including an extension water boom having sequenced sprinklers thereon, comprising the steps of:

placing a fluid transducer at the downstream side of said main water line for monitoring the changes in main line water pressure as the sprinklers on said extension water line are sequenced;

driving the L.R.D.U. at a predetermined speed (L.R.D.U. speed setting);

recording the output of said pressure transducer (end pressure) at predetermined intervals;

comparing the said recorded output (end pressure) at said predetermined intervals to the pressure recorded when all the sprinklers on said extension line are turned off (retracted end pressure);

and varying the speed of said L.R.D.U. according to a comparison of the end pressure and retracted end pressure.