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MOISTURE METER
The moisture contents of
grain seeds, food products, paper, soap powder and soap cakes is an important
factor in the production and packaging process. Moisture content of products
such as paper, cement, biscuits, etc. decides their shelf life. Moisture meters
are also used in the field of oil prospecting in oil wells. Different types of
moisture meters are available in the market which are based on the conductivity
measurements, capacitance measurements at de and at low frequencies. Number of
microwave and time domain moisture sensors are available in the market and are
being used in the soap and paper industries. Some of the sensors work on the
principle of measurement of fractional power absorption in the material to be tested.
Accuracy of such sensors depend upon the accuracy of detectors and source of
power. Novel moisture sensors developed by the inventors operate on the
principle of.
1.
Frequency
measurement; and
2.
Time
domain measurements
PRINCIPLES OF OPERATION
FREQUENCY DOMAIN
The frequency domain
moisture meter operates on the principle of non-destructive measurement. The
material under test is kept on the test vehicle and the frequency response of
the device is measured. Frequency response of the material can be displayed
with the help of computer or look-up table. The range of the moisture which can
be measured using the frequency domain moisture meter is 0-8%. The instrument
can be calibrated for the customers requirements in the range giving more
accurate results.
TIME DOMAIN MOISTURE
METER
The time domain Moisture
Meter works on the principle of change in the time duration of the passage of
the pulse through the material. The time domain moisture meter can work in a
completely non-destructive fashion unlike some of the time domain destructive
moisture meters in the market. Time domain data of a non-destructive moisture
meter is analysed using an online computer software. The analysis gives a
direct reading of moisture content with the pre-calibration of the material
under test.
INFRASTRUCTURES
Frequency Domain Moisture Meter –
Frequency Domain Moisture
Meter requires micro- wave frequency source, test vehicle and micro-wave
detectors. The frequency response of the test vehicle in the presence of the
material to be tested is recorded with the help of the instrumentation and
analysed with the help of a computer or look-up tables.
Time
Domain Moisture Meters –
The time domain Moisture
Meters use the sampling oscilloscope with the band width of 2-6 Ghz and the
test vehicle computer software specifically designed and a desk top computer.
ADVANTAGES
WORK DONE
A frequency domain moisture
meter has been conceptualized, fabricated and tested for wheat-grains,
chick-pea papers and rubber samples.
The moisture probe consists
of a microwave functional hybrid IC. Different configurations of probe circuits
have been tested as the technique covers a number of products, a suitable probe
may be fabricated according to the requirement. Calibration data is available
for a new type of materials. The frequency response of the hybrid IC loaded with
material under test has been extensively studied and an accuracy of better than
1% moisture has been obtained. An electromagnetic soft- ware for the analysis
of frequency response has been developed and tested to give the moisture
percentage accurately upto second decimal place. The software can run DOS or
UNIX platforms with or without WINDOWS systems (3.1 to 95,97,98, Open Win,
Sunview etc).
The moisture meter can also
be incorporated in the control system to monitor and control the moisture in
the industrial product.
The frequency response data
will be transferred to the computer via data acquisition card and on-line data
analysis will be performed.
The product/material to be
tested for moisture content will be pre-calibrated in the laboratory for various
moisture ranges.
A suitable test-vehicle -
(A functional hybrid IC) can be fabricated with the consultation of the
industry.
WORK DONE FOR TIME
DOMAIN MOISTURE METER
The time domain moisture
meter has been conceptual and tested for various materials of different
permittivities and thicknesses.
The moisture probe consists
of a ceramic plate carrying microwave transmission line which is loaded with
the material under test. Time domain response of the transmission line probe
with the material under test is recorded and analysed with the dedicated
electromagnetic computer software. The time domain moisture meter has the
accuracy of 2 ps. leading to the preset moisture accuracy upto second decimal
place. The software can run on any computer form 386 onwards on DOS, Windows
and UNIX platforms.
The moisture meters may be
incorporated in the control system to monitor and (control the moisture in the
industrial product).
The material to be tested
has been calibrated in the laboratory. The required range of suitable test
vehicle/functional hybrid IC will be designed accurately to suit the process
environment.
COST OF THE SYSTEM
1. FREQUENCY DOMAIN -
Hardware,
network analyses, scalar or vector or sweep oscillator or a continuous wave
oscillator, Microwave log, magnitude detector or a power meter.
Desk
Top Computer 386,486,pentium etc.
Sensor Cost : Rs.20,000/-
2. TIME DOMAIN –
Time
domain reflecto-meter or sampling oscilloscope, Test vehicle suitable for
measurement will be developed to suit the process envriroment Suitable probe
can be selected form six different designs developed. Desk top computer,
386,486,pentium etc.
Sensor cost : Rs.20,000/-
DEVELOPED AT –
Dept. of Electronics, S. P.
College, Tilak Road, Pune – 41130
NRDC
National Research Development Corporation, a Government of India Enterprise, is a premier technology transfer Corporation with four decades of experience. It has helped establish over one thousand projects in the small and medium scale sector in India and abroad. The supply of technologies and services to entrepreneurs abroad extend both in the developing and developed countries like USA, Germany, Malaysia, Burma, Nepal, Senegal, Madagascar, Indonesia, Philippines, Vietnam, Lanka, Kenya, Brazil, Bangladesh and Egypt.
Advantages of Indian
technologies:
Services offered by NRDC
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