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TDP Sap Velocity Probe

TDP Sap Velocity Probe

TDP Sap Velocity Probe

Product catalog summary
Features of TDP Sap Velocity Probe:
  • The TDP (Thermal Dissipation Probe) uses a dual needle, patented Granier design with enhancements from Dynamax.
  • It is easily inserted and removed for reuse, employing a constant heat, thermal dissipation method without heat pulses.
  • The probe provides continuous measurement with no waiting periods, using stainless steel needles that are Teflon coated for durability.
  • It is compatible with most data loggers and uses differentially wired T-type thermocouples.
  • Electronics and connectors are sealed and weatherproofed, with direct wiring to data loggers requiring one differential channel each.
Functionality:

The TDP sensor measures sap velocity, converting it to volumetric flow rate. It consists of two thermocouple needles, with the upper needle containing an electric heater. The temperature difference (dT) between the heated needle and the sapwood ambient temperature is used to calculate sap velocity.

For uniform trees in a closed canopy, one sensor per tree is sufficient. For irregular canopies or mixed species, multiple probes are recommended to ensure accurate flow calculations. Typically, two probe sets are used for trees 3” to 6” in diameter, and four for trees 6” to 18” in diameter. Calibration is advised for new species.

Specifications:
  • Models range from TDP-10 to TDP-100, with lengths from 10 mm to 100 mm and diameters from 1.2 mm to 1.65 mm.
  • Each model has specific power requirements, cable specifications, and heater resistance values.
  • Operating voltage varies with temperature, and signal output is consistent at 40 µV/°C across models.
Ordering Information:
  • Various models and configurations are available, including TDP-30, TDP-50, TDP-80, and TDP-100, each with specific cable lengths and connectors.
  • Additional systems and kits include the FLDL-TDP and FLGS-TDP XM1000, as well as Flow32 expansion kits for multiple sensors.
  • Installation kits and extension cables are available in various lengths and configurations to suit different probe models.
  • A dual adjustable voltage regulator (AVRD) is available for 6-12 V battery systems.
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Catalog excerpts

TDP Sap Velocity Probe-1

The Thermal Dissipation Probe (TDP) transpiration sensor measures sap velocity which is converted to volumetric flow rate. TDP is a simple and affordable device originally proposed by Granier. The basic TDP probe has two thermocouple needles inserted in the sapwood, the upper one containing an electric heater. The probe needles measure the temperature difference (dT) between the heated needle and the sapwood ambient temperature below. The dT variable and the maximum dTm at zero flow provide a direct conversion to sap velocity. For uniform trees in a closed canopy, only one sensor per tree is needed. For irregular canopies or with mixed species, sap flow varies around the circumference of large trees. Thus multiple probes are recommended in a single tree to make flow calculations accurately. Normally, install two probe sets per tree for trees 3" to 6" (75 to 150 mm) in diameter, and four probe sets per tree for trees 6" to 18" in diameter (>150 mm). Calibration is recommended for new species. Features ■ Dual needle, patented Granier design with Dynamax upgrades ■ Easily inserted & removed for reuse ■ Constant heat, thermal dissipation method; not heat pulse ■ Continuous measurement method ■ No waiting periods & no heat pulses ■ Stainless steel needles are Teflon coated for durability and longevity ■ Compatible with most data loggers ■ Differentially wired T- type thermocouples ■ Electronics and connectors are sealed and weatherproofed ■ Wires directly to data logger, one differential channel each Dynamax, Inc | 10808 Fallstone Rd #350 | Houston TX 77099 | USA | [email protected] | www.dynamax.com | 800-896-7108

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TDP Sap Velocity Probe-2

TDP-30 Sap Velocity Thermal Dissipation Probe 30 mm, 10 ft cable with connector TDP-50 Sap Velocity Thermal Dissipation Probe 50 mm, 10 ft cable with connector TDP-80 Sap Velocity Dual T/C Thermal Dissipation Probe 80 mm, 10 ft cable with connector TDP-100 Sap Velocity Profile Probe. 100 mm, 10 ft cable with connector FLDL-TDP TDP Sap Velocity System, fully assembled, DL2e based FLGS-TDP XM1000 TDP Sap Velocity System, fully assembled, CR1000 based FL32-GS8 Flow32 expansion kit for TDP probes with 8 TDP-30 sensors FL32-GS16 Flow32 expansion kit / same as above with 16 TDP-30 sensors and cables TDPJ1 Installation...

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