Tranzflo NZ Ltd

Specialists in Sap Flow Sensors

Our system can use either the T-max heat-pulse method (above) or the Tz (compensation) method (below) to measure sap movement


Home page Date: 29 Jan 2007

 Tranzflo NZ Ltd specializes in the supply of custom made sensors to monitor sap movement in plants.

 The measurements are based on the heat-pulse technique where a linear heater and two temperature probes are inserted radially into the tree stem (see diagram left).

 The heater probe is used to deliver a brief (1-2 s) pulse of heat energy, and a pair of temperature probes is used measure the subsequent rise in stem temperature.

 Probes are constructed from teflon or stainless steel tubing of 1.4 or 1.8 mm diameter. Each temperature probe contains up to 6 pairs of thermocouple sensors. The probe design can measure the radial profile of sap flow to a depth of 55 mm.

 A Campbell data logger (Campbell Scientific, USA) is used to control the heater output and measure the temperature signals from each sensor.

 The logger software can utilize both the Tmax and compensation (Tz) heat-pulse methods. A simple EXCEL spreadsheet is used to analyse the data.

 Plant water use is measured exactly in L per hour or L per day



Tranzflo NZ Ltd, 15 Parata St, Palmerston North 4410, NEW ZEALAND

Tel: +64-6-357-4600 Fax: +64-6-357-4601 E-mail:

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