Hukseflux FTN02 User manual

Copyright by Hukseflux | manual v1717 | www.hukseflux.com | [e-mail]
USER MANUAL FTN02
Field Thermal Needle System for Thermal
Resistivity / Conductivity Measurement
Hukseflux
Thermal Sensors

FTN02 manual v1717 2/49
Warning statements
The input voltage for charging should not exceed 5 VDC as
it may lead to overheating of the CRU02.
FTN02 is generally operated from its own 3.7 VDC battery.
This low voltage makes FTN02 safe to use in any
environment.
The TP09 needle is sharp and a potential risk to safety of
the operator. When not being used, it is recommended to
have a protective cover over the needle.
Putting more than 5 volt across the TP09 may result in
permanent damage to the sensor.
FTN02 requires a charged battery. With an empty battery,
approximately one hour of charging is required before
measurements can start. 11 hours of charging are preferred.
TP09 is robust but still vulnerable. In case of doubt if it can
penetrate the sample, the sample should be pre-drilled.
When calibrating in glycerol, the user is assumed to be
familiar with the glycerol safety data.
Like most measurement equipment, FTN02 is not suitable
for use in close proximity to high voltage cables when these
are in operation.

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Contents
Warning statements 2
Contents 3
List of symbols 4
Introduction 5
Ordering and checking at delivery 9
Included items 9
1Theory 10
1.1 General Non-Steady-State Probe Theory 10
1.2 Data analysis in the CRU02 11
1.3 Data review on PC 12
2FTN02 design considerations 13
3General Directions for Performing a Measurement 14
4FTN02 Specifications 15
4.1 Specifications of FTN02 15
5Arrival of a New FTN02 17
5.1 Preparation before Arrival 17
5.2Checking upon Arrival 17
6Quick System Test 18
7User Guide 20
7.1 Preparation 20
7.2 Cautionary Notes 20
7.3 Performing Measurements 20
7.4 Calibration 21
7.5 Menu Structure 22
7.6 Software 23
8Data Transfer, Archiving and Review 24
8.1 Connecting CRU02 and PC, downloading data to a PC 24
8.2 Reviewing Data in the Hukseflux CRU02 Manager 25
8.3 Reviewing Data in Excel 29
9Maintenance and Storage 31
10 Delivery and Spare Parts 32
11 Appendices 33
11.1 Appendix on modelling TP09 behaviour 33
11.2 Appendix on ASTM and IEEE standards 34
11.3 Appendix on insertion of the needle into hard soils 35
11.4 Appendix on typical soil thermal properties 36
11.5 Appendix on glycerol / glycerine 36
11.6 Appendix on electrical connection of TP-CRU02 37
11.7 Appendix on trouble shooting 38
11.8 Appendix on replacement of a TP 38
11.9 Appendix on battery charging 39
11.10 Appendix on downloading new software versions 39
11.11 Appendix on literature references 40
11.12 Glycerol Material Safety Data Sheet (93 / 112 EC) 41
11.13 International Chemical Safety Card for Glycerol 44
11.14 EC Declaration of Conformity 47

FTN02 manual v1717 4/49
List of symbols
Quantities Symbol Unit
Thermal diffusivity a m2/s
Distance from the heating wire r m
Heating cycle time H s
Thermal conductivity λW/(m·K)
Time t s
Temperature T K
Differential temperature, or temperature rise ∆T K
Electrical resistance ReΩ
Electrical resistance per meter Rem Ω/m
Thermal resistivity Rth m·K/W
Diameter D m
Volumetric heat capacity CvJ/(K·m2)
Density ρkg/m3
Current I A
Power P W
Power per meter Q W/m
Subscripts
Property of Pt 1000 sensor sen
Property of the heating wire heat
Property of the needle needle
Property, at t = 0, at t = 180, t =h seconds 0, 180, h

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Introduction
The FTN02 Field Thermal Needle System allows performing fast, on-site measurements
of the thermal resistivity or conductivity of soils. The sensor is a Non-Steady-State Probe
(NSSP), TP09, which is mounted at the tip of a lance (LN02). The system is operated
using a hand-held Control and Readout Unit (CRU02).
Figure 0.1 Key components of FTN02 system: from left to right thermal properties
sensor TP09, lance LN02 and Control and Readout Unit CRU02.
Figure 0.2 FTN02 system as delivered in its TC01 transport casing
Hukseflux is specialised in NSSP design. Alternative models, for instance for laboratory
use, are available at Hukseflux.
The measurement method is based on the so-called Non-Steady-State Probe (NSSP)
technique, which uses a probe (also called thermal properties sensor or thermal needle)
in which both a heating wire and a temperature sensor are incorporated. The probe is
inserted into the soil. From the response to a heating step the thermal resistivity (or the

FTN02 manual v1717 6/49
inverse value, the conductivity) of the soil can be calculated. The measurement with
FTN02 complies with the IEEE Guide for Soil Thermal Resistivity Measurements
IEEE Standard 442-1981(03) as well as with ASTM D5334-14 Standard Test Method for
Determination of Thermal Conductivity of Soil and Soft Rock. The main application of
FTN02 is route surveying for high voltage electric power cables and for heated pipelines.
In general an NSSP consists of a heating wire, representing a perfect line source, and a
temperature sensor capable of measuring the temperature at this source. The probe is
inserted into the soil that is investigated. The NSSP principle relies on a unique property
of a line source: after a short transient period the temperature rise, ∆T, only depends on
heater power, Q, and medium thermal conductivity, λ:
∆T = (Q / 4 πλ) (ln t + B)
With ∆T in K, Q in W/m, λin W/(m·K), t the time in s and B a constant. By measuring the
heater power, and tracing the temperature in time (for FTN02 typically during 5
minutes), λcan be calculated.

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Figure 0.3 FTN02 in operation. The Non-Steady-State Probe TP09 (1), mounted at the
tip of the Lance, LN02 (2), is inserted into the soil. The user performs control and
readout of the experiment from the CRU02 (3), using its keyboard and LCD. The CRU02
also contains a rechargeable battery for powering the TP09. The measurement result is
immediately generated. The temperature sensor is located in the middle of the TP09
needle, 1.48 m from the top of lance LN02.
1.5 m max.
Hukseflux
Thermal Sensors
1.48 m 1.57 m

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Figure 0.4 For additional quality insurance, the data of the measurements can be stored
and downloaded to the PC, and reviewed using the CRU02 software (1). The CRU02 (2)
can be connected to the PC by removing a cover (4) and connecting the USB cable on
both sides (3). Visual data review is required by ASTM.
Figure 0.5The CRU02 (1) can be recharged: Remove the cap (2), plug in the wall
socket adapter WSA02 (3) or the car adapter CA02 (4).
Chapter 1 contains information about theory of the NSSP and data analysis, chapter 2
summarises the design criteria and chapter 3 gives general directions for performing a
measurement. After chapter 4, the instrument specifications, the remaining chapters
contain information about testing the instrument on arrival, operation in the field,
operation of the software, calibration and maintenance.
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Thermal Sensors
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Thermal Sensors
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FTN02 manual v1717 9/49
Ordering and checking at delivery
Included items
FTN02 delivery includes the following items:
•Manual FTN02
•CRU02 Control and Readout Unit
•LN02 Lance
•TP09 Thermal Properties Sensor
•PT01 Protection tube
•TC01 Transport Casing
•JR01 Jar for glycerol, with polyester fibers
•Calibration certificate for TP09
•Factory Test Certificate for CRU02
•CRU02 Manager software on Hukseflux USB flash drive
•TP09 Thermal Properties Sensor (1 piece as spare)
•CA02 Car Adapter for 12 to 24 VDC
•WSA02 Wall Socket Adapter for 220 or 110 VAC
•USB Cable for CRU02 to PC connection
Figure 0.6 FTN02 system unpacked from its TC01 transport casing
Delivery does NOT include glycerol fluid. This has to be locally obtained by the customer.
FTN02 software can be updated by the customer. New software versions are available on
a regular basis. For available software / firmware updates, please check:
http://www.hukseflux.com/page/downloads

FTN02 manual v1717 10/49
1Theory
1.1 General Non-Steady-State Probe Theory
For determining the thermal conductivity of materials various types of measurement
equipment can be used. In general one can make a distinction between steady-state
techniques in which the investigated sample is supposed to reach a perfect thermal
equilibrium, and non-steady-state techniques. In non-steady-state techniques the
material properties are determined while the sample temperature still changes.
The main advantage of steady-state techniques is the simplicity of the analysis of
stabilised constant sensor signals. The main advantages of non-steady-state techniques
are the short measurement time and the fact that the sample dimensions do not
necessarily enter the equation.
The only Non-Steady-State technique that has been standardised is the one using a
single needle probe (Non-Steady-State Probe or NSSP) like TP09.
ASTM D5334-14 and IEEE Std 442-1981(03) “Standard Test Methods" specify the use of
the NSSP in soil and soft rock. More information about these standards can be found in
the appendices.
In general a NSSP consists of a heating wire, representing a perfect line source and a
temperature sensor capable of measuring the temperature at this source. The probe is
inserted into the soil that is investigated. The NSSP principle relies on a unique property
of a line source: after a short transient period the temperature rise, ∆T, only depends on
heater power, Q, and medium thermal conductivity, λ:
∆T = (Q / 4 πλ) (ln t + B) Formula 1.1.1
With ∆T in K, Q in W/m, λin W/(m·K), t the time in s and B a constant.
The thermal conductivity can be calculated from two measurements at t1and t2. For TP09
(6.35 mm diameter) both t1and t2are higher than 100 s, and typically 150 s apart. ∆T is
the temperature difference between the measurements at time t1and t2, taking t = 0 at
the moment that the heating starts.
λ= (Q / 4 π∆T) ln(t2/ t1) Formula 1.1.2
The sample size is not critical, as long as a radius around needle is covered that is
roughly 50 times the needle radius, in case of TP09 (the needle of FTN02), which has a
3.175 mm radius: 160 mm. (please note that with low conductivity media like dry sand,
glycerol and Perspex, the sample diameter can be reduced to 100 mm)