Supplemental irrigation programmer

• US 6,145,755 A
• Filed: 10/05/1999
• Issued: 11/14/2000
• Est. Priority Date: 07/23/1999
• Status: Expired due to Fees

• Current Assignee: Louis V. Feltz
• Original Assignee: Louis V. Feltz
• Inventors: Feltz, Louis V.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Ganey, Steven J.
• Application Number:
  US09/413,719
• Time in Patent Office: 406 Days
• Field of Search: 239/1, 239/63, 239/64, 239/67, 239/69, 239/70, 239/99, 239/551, 239/562, 239/DIG. 15, 137/78.1, 137/78.2, 137/78.5, 137/624.11, 137/624.18, 137/624.2, 700/11, 700/284, 47/48.5
• US Class Current: 239/1
• CPC Class Codes: A01G 25/167 Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
• CPC Class Codes: Y10S 239/15 Sprinkler systems with controls
• CPC Class Codes: Y10T 137/1842 Ambient condition change responsive
• CPC Class Codes: Y10T 137/1939 Atmospheric
• CPC Class Codes: Y10T 137/86389 Programmer or timer

Abstract

An irrigation system that controls the amount of water to be applied based upon specific historical meteorological data including relative humidity, evapotranspiration data, and precipitation. The invention is also of a method for determining the optimal time of day to measure actual relative humidity, and for setting the relative humidity set-point.

Claims

1. An apparatus for controlling an amount of irrigation water to be applied to a given area, said apparatus comprising:

a) means to set time and duration for at least one irrigation valve to remain open so the amount of irrigation water can be delivered to the given area;

b) means to measure actual relative humidity;

c) means to set a preferred time to measure an actual relative humidity value;

d) means to compare said actual relative humidity value to a pre-selected relative humidity value to determine if irrigation water should be applied;

e) means to set a time differential between said preferred time said actual relative humidity is measured and said time of at least one said irrigation valve is scheduled to open; and

f) means to prevent opening of said irrigation valve if said actual measured relative humidity is greater than said pre-selected relative humidity value.

2. The apparatus of claim 1 wherein said means to measure said actual relative humidity comprises a humidistat comprising means to pre-select said relative humidity value and compare said relative humidity value to said actual measured relative humidity.

3. The apparatus of claim 1 wherein said means to set said time differential comprises a time-delay circuit.

4. The apparatus of claim 1 wherein said means to set said time differential comprises a time delay determined by at least one irrigation station of an irrigation programmer.

5. The apparatus of claim 1 wherein said means to prevent opening of said irrigation valve comprises a switch operated by an electrical relay.

6. A method for controlling an amount of irrigation water to be applied to a given area, the method comprising the steps of:

a) setting time and duration for at least one irrigation valve to remain open so the amount of irrigation water can be delivered to the given area;

b) measuring actual relative humidity;

c) setting a preferred time to measure an actual relative humidity value;

d) setting a pre-selected relative humidity value;

e) comparing the actual relative humidity value to the pre-selected relative humidity value to determine if irrigation water should be applied;

f) setting a time differential between the time the actual relative humidity is measured and the time of at least one irrigation valve is scheduled to open; and

g) preventing opening of the irrigation valve if the actual measured relative humidity is greater than the pre-selected relative humidity value.

7. The method of claim 6 wherein the step of setting the preferred time to measure the relative humidity value comprises the steps of:

a) graphing historical daily maximum and minimum relative humidity data, daily precipitation data, and daily evapotranspiration data on a single graph for a given time period;

b) comparing maximum and minimum relative humidity plots with evapotranspiration plot to determine which relative humidity data best correlates with the evapotranspiration data; and

c) selecting a time at which the maximum or minimum relative humidity data was taken that best correlates with the evapotranspiration data.

8. The method of claim 6 wherein the step of setting the pre-selected relative humidity value comprises the steps of:

a) determining the amount of irrigation water required on an average daily basis to correlate with periods of high daily evapotranspiration data;

b) calculating total amount of irrigation water applied and natural precipitation, and total amount of water lost due to evapotranspiration for a given period;

c) subtracting the total amount of water lost due to evapotranspiration from the total amount of water applied by irrigation and natural precipitation to arrive at an amount of water applied in excess;

d) dividing the amount of water applied in excess by the volume of water to be required on an average daily basis to determine a number of days that irrigation should not be applied for the given period; and

e) setting the pre-selected relative humidity value such that the number of days determined in step (d) is approximately a number of days that have a relative humidity value above the pre-selected relative humidity value.

9. The method of claim 6 wherein the step of measuring the actual relative humidity comprises a humidistat.

10. The method of claim 6 wherein the step setting the time differential comprises a time-delay circuit.

11. The method of claim 6 wherein the step setting the time differential comprises a time-delay determined by at least one irrigation station of an irrigation programmer.

12. The method of claim 6 wherein the step of preventing opening of the irrigation value comprises a switch operated by an electrical relay.