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US 12,723,904 B2Granted
Sap flow sensor and method of determining sap flow velocity
AssigneeTreetoscope Ltd
InventorOri Ahiman
Life of this patent
Estimating the term…
Abstract
A method for determining sap flow velocity, constituted of: providing a heat source and a thermal sensor on a single needle: at a no-flow condition, providing first heat energy to produce a steady state first pre-determined temperature rise: determining a total amount of first heat energy provided to produce the first pre-determined temperature rise: at a flow condition: providing second heat energy to produce a steady state second pre-determined temperature rise: determining a total amount of second heat energy provided to produce the second pre-determined temperature rise: and determining a sap flow rate responsive to the determined total amount of first heat energy and the determined total amount of second heat energy.
Claims8
A method for determining for determining sap flow density, comprising:
- under a no-flow condition:
- supplying a first heat energy to a plant-inserted, single needle sap flow sensor so as to achieve a pre-determined steady state temperature;
- generating a no-flow temperature distribution, wherein the no-flow temperature distribution is calculated in accordance with a temperature distribution equation:
- T
-
- (
- x
- )
- =
- 1
- Δ
-
- T
- ·
- erf
-
- c
-
- (
- x
- β
- )
- wherein:
- x is distance from the needle in a direction parallel to a flow direction,
- T(x) is temperature as a function of x,
- ΔT is a change of temperature,
- erfc is a Gauss error function,
- β is a decay parameter;
- determining a no-flow heat plume endpoint Z1 displaced in an x-axis under the no-flow condition;
- under a flow condition:
- supplying a second heat energy to the plant-inserted, single needle sap flow sensor so as to achieve the pre-determined steady state temperature;
- generating a flow temperature distribution, wherein the flow temperature distribution is calculated in accordance with the temperature distribution equation;
- determining a flow heat plume endpoint Z2 displaced in an x-axis under the flow condition wherein the determining the no-flow heat plume endpoint Z1 and the flow heat plume endpoint Z2 is implemented by numerically solving a heat balance equation under the no-flow condition and the flow condition, respectively, wherein the heat balance equation is:
- Q
- 2
- =
- C
- p
-
- ∫
- 0
- Z
-
- 2
- ∫
- 0
- Z
-
- 1
- Tdxdy
- wherein:
- Q2 is the total heat energy supplied until steady state,
- Cp is fluid heat capacity,
- x is distance from the needle in a direction parallel to flow direction,
- y is distance from the needle orthogonal to flow direction;
- and
- calculating the sap flow density (SFD) in accordance with a difference between heat plume endpoints Z2 and Z1 and times needed to achieve the pre-determined steady state temperature in no-flow and flow conditions, wherein calculating the SFD is implemented in accordance with:
- SFD
- =
- ζ
-
- Z
-
- 2
- -
- Z
-
- 1
- Δ
-
- t
-
- 2
- wherein:
- ζ is a calibration factor,
- Δt2 represents time to steady state under flow condition.
73 more elements
A sap flow (SF) sensor comprising:
- a single needle, comprising a heat source and a thermal sensor;
- and
- a control unit in communication with the needle, the control unit arranged to:
- under a no-flow condition:
- supply a first heat energy to the plant-inserted single needle, so as to achieve a pre-determined steady state temperature;
- calculate a no-flow temperature distribution, wherein the no-flow temperature distribution is calculated in accordance with a temperature distribution equation:
- T
-
- (
- x
- )
- =
- 1
- Δ
-
- T
- ·
- erf
-
- c
-
- (
- x
- β
- )
- wherein:
- x is distance from the needle in a direction parallel to a flow direction,
- T(x) is temperature as a function of x,
- ΔT is a change of temperature,
- erfc is a Gauss error function,
- β is a decay parameter;
- determine a no-flow heat plume endpoint Z1 displaced in an x-axis under the no-flow condition;
- under a flow condition:
- supply a second heat energy to the plant-inserted single needle, so as to achieve the pre-determined steady state temperature;
- calculate a flow temperature distribution, wherein the flow temperature distribution is calculated in accordance with the temperature distribution equation;
- determine a flow heat plume endpoint Z2 displaced in an x-axis under the flow condition wherein the determining the no-flow heat plume endpoint Z1 and the flow heat plume endpoint Z2 is implemented by numerically solving a heat balance equation under the no-flow condition and the flow condition, respectively, wherein the heat balance equation is:
- Q
- 2
- =
- C
- p
-
- ∫
- 0
- Z
-
- 2
- ∫
- 0
- Z
-
- 1
- Tdxdy
- wherein:
- Q2 is the total heat energy supplied until steady state,
- Cp is fluid heat capacity,
- x is distance from the needle in a direction parallel to flow direction,
- y is distance from the needle orthogonal to flow direction;
- and calculate the sap flow density (SFD) in accordance with a difference between heat plume endpoints Z2 and Z1 and times needed to achieve the pre-determined steady state temperature in no-flow and flow conditions, wherein calculating the SFD is implemented in accordance with:
- SFD
- =
- ζ
-
- Z
-
- 2
- -
- Z
-
- 1
- Δ
-
- t
-
- 2
- wherein:
- ζ is a calibration factor,
- Δt2 represents time to steady state under flow condition.
75 more elements
Dependencies are inferred from the claim text.