Absorbent rain sensor with retention basin

• US 9,655,311 B1
• Filed: 12/10/2013
• Issued: 05/23/2017
• Est. Priority Date: 12/10/2013
• Status: Active Grant

• Current Assignee: Hunter Industries Incorporated
• Original Assignee: Hunter Industries Incorporated
• Inventors: Bell, James A.
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): PARK, JOHN C
• Application Number:
  US14/102,276
• Time in Patent Office: 1,260 Days
• CPC Class Codes: A01G 25/16 Control of watering
• 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: G01W 1/14 Rainfall or precipitation gauges measuring volume in general G01F

Abstract

A rain sensor can be configured to shut off one or more irrigation devices during and/or after a period of rainfall. The rain sensor can include a moisture basin mounted therein. The moisture basin houses an absorbent element configured to expand in at least one direction when wetted. Expansion of the absorbent element can activate a signal actuator to generate a shut off signal to one or more irrigation devices. The moisture basin can retain excess moisture when the absorbent element is fully saturated.

Claims

1. An irrigation control system comprising:

a control unit; and

a rain sensor in communication with the control unit, the rain sensor comprising;

a sensor housing;

a first moisture-absorbent element within the sensor housing and in communication with ambient via a first aperture in the sensor housing, the first moisture-absorbent element configured to expand to a wet state from a dry state as the first moisture-absorbent element absorbs liquid, the first moisture-absorbent element having a first drying rate;

a moveable accumulator cup configured to move within the sensor housing, the accumulator cup having a liquid-impervious base and one or more liquid-impervious sidewalls extending upward from the base, the liquid-impervious base and one or more liquid-impervious sidewalls forming a cup volume;

a second moisture-absorbent element within the sensor housing and positioned at least partially within the cup volume, the second moisture-absorbent element in communication with ambient via a second aperture in the sensor housing, the second moisture-absorbent element configured to expand when transitioned from a dry state to a wet state, the second moisture-absorbent element having a second drying rate slower than the first drying rate, wherein the moveable accumulator cup is configured to transition between a first position and a second position with respect to the sensor housing in response to transition of the second moisture-absorbent element between the dry state and the wet state; and

a signal actuator configured to transition between a first position and a second position, the signal actuator biased to the first position when the moveable accumulator cup is in its first position, the signal actuator transitions to the second position when one or more of the first moisture-absorbent element and the second moisture-absorbent element is in its wet state;

the accumulator cup configured to store a volume of liquid in excess of the liquid within the fully saturated second moisture-absorbent element, the volume of excess liquid in contact with at least a portion of the second moisture-absorbent element.

2. The system of claim 1, wherein the one or more liquid-impervious sidewalls have a sidewall height, the second moisture-absorbent element has an element height extending between the base of the accumulator cup and an upper retaining structure, and when the second moisture-absorbent element is dry the sidewall height is less than forty percent the element height and greater than five percent the element height.

3. The system of claim 2, wherein the second moisture-absorbent element comprises a plurality of stacked moisture-absorbent discs.

4. The system of claim 1, wherein the one or more liquid-impervious sidewalls have a sidewall height, the second moisture-absorbent element has an element height extending between the base of the accumulator cup and an upper retaining structure, and the sidewall height is greater than ten percent the element height and less than sixty percent the element height when the second moisture-absorbent element is dry.

5. The system of claim 1, wherein the one or more liquid-impervious sidewalls include one or more notches, the one or more notches in an outer surface of the one or more liquid-impervious sidewalls to facilitate drainage of overflow liquid from the accumulator cup.

6. The system of claim 5, wherein the one or more notches are in an outer surface of the one or more liquid-impervious sidewalls to facilitate drainage of overflow liquid from the accumulator cup.

7. The system of claim 1, wherein the accumulator cup includes a central post extending upward from the liquid-impervious base, the second moisture-absorbent element mounted on the central post.

8. An irrigation control sensor comprising:

a sensor housing;

a signal actuator configured to transition between a first position and a second position, the signal actuator biased to the first position;

a moisture accumulator cup mounted in the sensor housing and defining a accumulator volume; and

a moisture-absorbent element mounted in the sensor housing and positioned at least partially within the accumulator volume, the moisture-absorbent element in communication with ambient via an aperture in the sensor housing, the moisture-absorbent element configured to expand as the moisture-absorbent element absorbs liquid and configured to move the moisture accumulator cup with respect to the sensor housing when the moisture-absorbent element expands;

the signal actuator transitioning from the first position to the second position as the second moisture-absorbent element expands;

the moisture accumulator cup retaining a volume of liquid outside the moisture-absorbent element when the moisture-absorbent element reaches a maximum liquid absorption, the volume of liquid in contact with the moisture-absorbent element.

9. The sensor of claim 8, wherein the moisture accumulator cup has one or more sidewalls having a sidewall height, the sidewall height being less fifty percent of a height of the moisture-absorbent element when the moisture-absorbent element is dry.

10. The sensor of claim 8 comprising a resilient structure configured to bias the moisture accumulator cup in an upward direction.

11. The sensor of claim 8 comprising a resilient structure, the moisture-absorbent element moving the moisture accumulator cup in an expansion direction as the moisture-absorbent element absorbs liquid, the resilient structure biasing the moisture accumulator cup in a direction substantially opposite the expansion direction.

12. The sensor of claim 8, wherein the moisture accumulator cup includes a cup base having a substantially flat upper surface, the cup base being liquid-impervious.

13. A rain sensor comprising:

a sensor housing;

a signal actuator configured to transition between a first position and a second position, the signal actuator biased to the first position;

a moisture accumulator cup defining an accumulator volume and moveably mounted in the sensor housing, the moisture accumulator cup configured to hold a volume of liquid within the accumulator volume; and

a moisture-absorbent element mounted in the sensor housing and positioned at least partially within the accumulator volume, the moisture-absorbent element in communication with ambient via an aperture in the sensor housing, the moisture-absorbent element configured to expand when transitioned from a dry state to a wet state, the moisture-absorbent element configured to move the moisture accumulator cup when transition from the dry state to the wet state;

the signal actuator to transition from the first position to the second position as the moisture-absorbent element is transitioned to the wet state from the dry state;

the moisture accumulator cup retaining the volume of liquid within the accumulator volume and outside the moisture-absorbent element when liquid is introduced to the moisture-absorbent element in the wet state, the volume of liquid in contact with at least a portion of the moisture-absorbent element;

wherein the moisture accumulator cup is configured to transition the signal actuator from the first position to the second position when the moisture-absorbent element is transitioned from the dry state to the wet state.

14. The sensor of claim 13, wherein the signal actuator comprises a hinged arm attached to the sensor housing at a hinge point, the hinged arm biased upward by a resilient element.

15. The sensor of claim 14, wherein the moisture accumulator cup is moved into contact with the hinged arm when the moisture-absorbent element expands.

16. The sensor of claim 13, wherein the signal actuator comprises a permanent magnet.

17. The sensor of claim 16, wherein the permanent magnet moves relative to a Hall effect sensor when the signal actuator is transitioned between the first position and the second position, movement of the permanent magnet affecting a signal generated by the Hall effect sensor.

18. The sensor of claim 16, wherein the permanent magnet moves relative to a reed switch when the signal actuator is transitioned between the first position and the second position, movement of the permanent magnet opening and closing the reed switch.

19. The sensor of claim 13, wherein the signal actuator is fixedly attached to the accumulator cup.

20. A rain sensor comprising:

a sensor housing;

a moisture accumulator cup defining an accumulator volume and mounted in the sensor housing, the moisture accumulator cup configured to hold a volume of liquid within the accumulator volume; and

a moisture-absorbent element mounted in the sensor housing and positioned at least partially within the accumulator volume, the moisture-absorbent element in communication with ambient via an aperture in the sensor housing, the moisture-absorbent element configured to expand when transitioned from a dry state to a wet state;

the moisture accumulator cup configured to move in response to expansion of the moisture-absorbent element to exert a force upon a signal actuator as the moisture-absorbent element is transitioned to the wet state from the dry state;

the moisture accumulator cup retaining the volume of liquid within the accumulator volume and outside the moisture-absorbent element when liquid is introduced to the moisture-absorbent element in the wet state, the volume of liquid in contact with at least a portion of the moisture-absorbent element.