SHB method with variable power Stem diameters from 6 to 20 mm Extremely high efficiency Low energy consumption Flexible channel number in a set Fits to common dataloggers

Variable power
Constant dT (2, 4 or 8 K)
Two sensor sizes
6 to 12 mm
10 to 20 mm
Output in [kg/h]
Flexible external heater
Electronic modules in one box with the datalogger
Power requirements proportional to sap flow rate – fits to solar powering

Briefly:
The measuring principle is based on the stem heat balance method (SHB) with external heating and internal temperature sensing (Lindroth et al. 1995, Čermák et al. 2004). The senor consists of two similar cylindrical parts. Each part wraps the stem with insulation foam. One part contains linear heating elements which are gently pressed to the stem by soft foam. A needle thermocouple is inserted to the stem in radial direction at the level of upper edge of heating elements (in direction of water movement). Second cylinder has no heaters and it just covers the reference needle thermocouple located with respect to the thermal symmetry. The water passing along the sensor is warmed and the temperature increase is measured with thermocouples as the water leaves the heated space. The feedback loop of EMS 62 module maintains the temperature difference at preset level 2 K or 4 K (and 8 K by EMS 62A module). Then, the input power is directly proportional to the amount of water passing the sensor in terms of kg/hr. However, there is still a part of energy that is dissipated by heat losses from the sensor. The measuring system includes the EMS 62 controlling module, sap flow sensor SF 60, radiation shield, connecting cables and a datalogger. There are two dimensions of sap flow sensors according to the stem thickness (6 to 12 mm and 10 to 20 mm). The module electronics includes the power unit, the temperature and heating power measuring circuits, the controlling system and the output D/A convertor. Electronic circuits are designed for maximal power efficiency in order to save batteries. The power consumption is directly proportional to heating power.

For more info: jiri.kucera@emsbrno.cz

Download
pdf Data sheet
pdf User’s manual
pdf Installation guide