Title of Invention	A NOVEL SENSOR FOR THE DETERMINATION OF MOISTURE IN AGRICULTURAL PRODUCE AND A MOISTURE SENSING DEVICE MADE THEREOF.
Abstract	A novel sensor for the determination of moisture in agricultural produce which comprises a nonporous ceramic substrate characterised in that the said substrate having dielectric constant within 100, the said substrate being provided with a plurality of thick film planar electrodes of thickness in the range 20-30µm, width in the range of 1-2 mm and interelectrode gap in the range of 0.5-1.0 mm, the said planar electrodes being connected to two terminals in an alternate manner

Title of Invention

A NOVEL SENSOR FOR THE DETERMINATION OF MOISTURE IN AGRICULTURAL PRODUCE AND A MOISTURE SENSING DEVICE MADE THEREOF.

Abstract

A novel sensor for the determination of moisture in agricultural produce which comprises a nonporous ceramic substrate characterised in that the said substrate having dielectric constant within 100, the said substrate being provided with a plurality of thick film planar electrodes of thickness in the range 20-30µm, width in the range of 1-2 mm and interelectrode gap in the range of 0.5-1.0 mm, the said planar electrodes being connected to two terminals in an alternate manner

Full Text	The invention relates to a novel sensor for the determination of moisture in agricultural produce and a moisture sensing device made thereof. This invention particularly relates to a novel sensor based on the absorption of electric flux by the material under test. Moisture measurement in cellulose, grains are very common. At present measurement of moisture in cellulose materials is widely used in various scientific and industrial applications and measurement of moisture in 0-20% level plays a vital role in the process. A few common examples are various kinds of chemical processes where specific range of moisture is necessary for the continuous curing of cellulose materials like the production of tea. In the known art, sensors for detection of moisture in agriculture produce are RC phase shift type or capacitance type, both of which have drawbacks such as unreliable sensitivity and high cost. In this context reference may be made to research paper of 'Measurement of moisture loss for the intelligent on-line monitoring system for withering process in tea industryl, published in the proceedings of 32nd Tocklai Conference, 1993 where measurement of capacitance in tea leaves was taken as an index for moisture loss. In this case the moisture measurement sub- system was based on the vector impedance behavior of the tea leaves. The impedance of the tea leaves was measured at multiple frequencies, out of which resistive and capacitative components are extracted. In another version of the sensor, the phase behavior of the leaf to fixed frequency excitation is considered and has given better results on heterogeneous tea samples. The main disadvantages of the above noted prior art are : (1) Require large area-, (2) Large amount of sample^ (3) High cost -j (4)3?epends on sample orientation and packing density and so the result is not reproducible. The main object of the present invention is to provide a novel sensor for the determination of moisture in agricultural produce, which obviates the above noted drawbacks. Another object is to provide a moisture sensing device incorporating the novel sensor of the present invention capable of measuring in the range of 0-20% moisture level with resolution 0.1% and response time less than 1secs. Yet another object of the present invention is to provide a novel moisture sensor which works on the principal of change in power factor (pf) of the material under test. Still another object of the present invention is to provide a moisture sensor having a nonporous ceramic substrate. Accordingly the present invention provides a novel sensor for the determination of moisture in agricultural produce which comprises a nonporous ceramic substrate characterized in that the said substrate having dielectric constant within 100, the said substrate being provided with a plurality of thick film planar electrodes of thickness in the range 20-30(j.m, width in the range of 1-2 mm and interelectrode gap in the range of 0.5-1.0 mm, the said planar electrodes being connected to two terminals in an alternate manner. In an embodiment of the present invention the not is ceramic substrate used is such as barium titanate, alumina, zirconia, yttria-stabilized zirconia or magnesia. In another embodiment of the present invention the thickness of the nonporous ceramic substrate is in the range of 3-5mm. In still another embodiment of the present invention the nonporous ceramic substrate has pore size less than 0.1 µm. In yet another embodiment of the present invention the electrodes are made of thick film Ag-Pd or Ag pastes. The moisture sensor of present invention essentially consists of a non-porous ceramic substrate with dielectric constant of the order of 7-14, having planner thick film electrodes of which alternate electrodes are connected to the same potential. Accordingly the present invention provides a moisture sensing device for measuring moisture in agricultural produce which comprises a novel moisture sensor, as described above, being connected to a conventional tuned circuit, the output of the said tuned circuit being converted to dc by conventional means and the resultant output being connected to an analog or digital display. The novel moisture sensor of the present invention works on the principle that flux from the electrodes passes through the material under test and the power factor of the material changes. The change in power factor is measured in terms of voltage. The difference in voltage is calibrated in different moisture levels in agricultural produce such as tea leaves/green leaves. The sensor is capable of measuring moisture level from high to low concentration of the order of 0-20%. The uniqueness of the present invention lies in the fact that the sensor shows good sensitivity in the range of 0-20%. As per known art, sensors for detection of moisture in agricultural produce are all based on large capacitance or RC phase shift technology that has drawbacks such as sensitivity is not reliable and manufacturing cost is high. The novelty of the present invention resides in providing a powerfactor type moisture sensor. The inventive step of the present invention lies in providing a sensor having ceramic non-porous substrate with thick film planar electrodes. The following examples illustrate the invention in the manner in which it may be carried out in practice. However, this should not limit the scope of the present invention. Example 1 A non-porous Alumina substrate of thickness 3mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 20µm width of 1mm and interelectrode gap of 0.5mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 10.21mV for a sample of moisture content of 50%. Example 2 A non-porous Zirconia substrate of thickness 5mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 20u,m width of 1mm and interelectrode gap of 0.7mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 14.2mV for a sample of moisture content of 7%. Example 3 A non-porous Yttria stabilized zirconia substrate of thickness 4mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 30µm width of 2mm and interelectrode gap of 1 .0mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 18.25mV for a sample of moisture content of 9%. Example 4 A non-porous Magnesia substrate of thickness 3mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 25 µm width of 2mm and interelectrode gap of 0.9mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 21.14mV for a sample of moisture content of 10%. Example 5 A non-porous Alumina substrate of thickness 5mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 25µm width of 2mm and interelectrode gap of 0.5mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 12.04mV for a sample of moisture content of 6%. Example 6 A non-porous Barium titanate substrate of thickness 4mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 30um width of 1mm and interelectrode gap of 0.6mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 11.35mV for a sample of moisture content of 5.5%. The main advantages of the present invention are: 1. High sensitivity from 0-20% moisture level 2. Fast response ( 3. Temperature stability over the range. 4. Not sensitive to electrical noise. 5. Practically no drift over time. 6. Low cost compared to conventional sensor available in the market. 7. The sensor can be used continuously for a long period of time. We Claim: 1. A novel sensor for the determination of moisture in agricultural produce which comprises a noriporous ceramic substrate characterized in that the said substrate having dielectric constant within 100, the said substrate being provided with a plurality of thick film planar electrodes of thickness in the range 20-30µm, width in the range of 1-2 mm and interelectrode gap in the range of 0.5-1.0 mm, the said planar electrodes being connected to two terminals in an alternate manner. 2. a novel sensor as claimed in Claim 1 wherein the said ceramic substrate used selected from Barium titan ate, Alumina, Zirconia, Yuttria stabilized zirconia or Magnesia. 3. A novel sensor as claimed in Claims 1-2 wherein the thickness of the non- porous substrate is in the range of 3-5 mm. 4. A novel sensor as claimed in Claims 1 -3 wherein the pore size of then on- porous ceramic substrate is within 0.1 µm. 5. A novel sensor as claimed in Claims 1-4 wherein the electrodes are made of Ag-Pd or Ag thick film paste. 6. A moisture sensing device for measuring moisture in agricultural produce which comprises a novel moisture sensor as claimed in Claims 1-5 being connected to a conventional tuned circuit, the output of the said tuned circuit being converted to dc by conventional means and the resultant output being connected to an analog or digital display. 7. A novel sensor for the determination of moisture in agricultural produce substantially as herein described with reference to the examples.

Full Text

The invention relates to a novel sensor for the determination of moisture in agricultural produce and a moisture sensing device made thereof. This invention particularly relates to a novel sensor based on the absorption of electric flux by the material under test.
Moisture measurement in cellulose, grains are very common. At present measurement of moisture in cellulose materials is widely used in various scientific and industrial applications and measurement of moisture in 0-20% level plays a vital role in the process. A few common examples are various kinds of chemical processes where specific range of moisture is necessary for the continuous curing of cellulose materials like the production of tea.
In the known art, sensors for detection of moisture in agriculture produce are RC phase shift type or capacitance type, both of which have drawbacks such as unreliable sensitivity and high cost.
In this context reference may be made to research paper of 'Measurement of moisture loss for the intelligent on-line monitoring system for withering process in tea industryl, published in the proceedings of 32nd Tocklai Conference, 1993 where measurement of capacitance in tea leaves was taken as an index for moisture loss. In this case the moisture measurement sub-

system was based on the vector impedance behavior of the tea leaves. The impedance of the tea leaves was measured at multiple frequencies, out of which resistive and capacitative components are extracted. In another version of the sensor, the phase behavior of the leaf to fixed frequency excitation is considered and has given better results on heterogeneous tea samples.
The main disadvantages of the above noted prior art are :
(1) Require large area-,
(2) Large amount of sample^
(3) High cost -j
(4)3?epends on sample orientation and packing density and so the result is not reproducible.
The main object of the present invention is to provide a novel sensor for the determination of moisture in agricultural produce, which obviates the above noted drawbacks.
Another object is to provide a moisture sensing device incorporating the novel sensor of the present invention capable of measuring in the range of 0-20% moisture level with resolution 0.1% and response time less than 1secs.

Yet another object of the present invention is to provide a novel moisture sensor which works on the principal of change in power factor (pf) of the material under test.
Still another object of the present invention is to provide a moisture sensor having a nonporous ceramic substrate.
Accordingly the present invention provides a novel sensor for the determination of moisture in agricultural produce which comprises a nonporous ceramic substrate characterized in that the said substrate having dielectric constant within 100, the said substrate being provided with a plurality of thick film planar electrodes of thickness in the range 20-30(j.m, width in the range of 1-2 mm and interelectrode gap in the range of 0.5-1.0 mm, the said planar electrodes being connected to two terminals in an alternate manner.
In an embodiment of the present invention the not is ceramic substrate used is such as barium titanate, alumina, zirconia, yttria-stabilized zirconia or magnesia.
In another embodiment of the present invention the thickness of the nonporous ceramic substrate is in the range of 3-5mm.

In still another embodiment of the present invention the nonporous ceramic substrate has pore size less than 0.1 µm.
In yet another embodiment of the present invention the electrodes are made of thick film Ag-Pd or Ag pastes.
The moisture sensor of present invention essentially consists of a non-porous ceramic substrate with dielectric constant of the order of 7-14, having planner thick film electrodes of which alternate electrodes are connected to the same potential.
Accordingly the present invention provides a moisture sensing device for measuring moisture in agricultural produce which comprises a novel moisture sensor, as described above, being connected to a conventional tuned circuit, the output of the said tuned circuit being converted to dc by conventional means and the resultant output being connected to an analog or digital display.
The novel moisture sensor of the present invention works on the principle that flux from the electrodes passes through the material under test and the power factor of the material changes. The change in power factor is measured in terms of voltage. The difference in voltage is calibrated in different moisture levels in agricultural produce such as tea leaves/green

leaves. The sensor is capable of measuring moisture level from high to low concentration of the order of 0-20%. The uniqueness of the present invention lies in the fact that the sensor shows good sensitivity in the range of 0-20%. As per known art, sensors for detection of moisture in agricultural produce are all based on large capacitance or RC phase shift technology that has drawbacks such as sensitivity is not reliable and manufacturing cost is high.
The novelty of the present invention resides in providing a powerfactor type moisture sensor. The inventive step of the present invention lies in providing a sensor having ceramic non-porous substrate with thick film planar electrodes.
The following examples illustrate the invention in the manner in which it may be carried out in practice. However, this should not limit the scope of the present invention.
Example 1
A non-porous Alumina substrate of thickness 3mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen

printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 20µm width of 1mm and interelectrode gap of 0.5mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 10.21mV for a sample of moisture content of 50%.
Example 2
A non-porous Zirconia substrate of thickness 5mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 20u,m width of 1mm and interelectrode gap of 0.7mm are printed were dried and fired at temperature of 850°C for 60min.

The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 14.2mV for a sample of moisture content of 7%.
Example 3
A non-porous Yttria stabilized zirconia substrate of thickness 4mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 30µm width of 2mm and interelectrode gap of 1 .0mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 18.25mV for a sample of moisture content of 9%.

Example 4
A non-porous Magnesia substrate of thickness 3mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 25 µm width of 2mm and interelectrode gap of 0.9mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 21.14mV for a sample of moisture content of 10%.
Example 5
A non-porous Alumina substrate of thickness 5mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen

printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 25µm width of 2mm and interelectrode gap of 0.5mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is converted to DC voltage and the final output is connected to an analog or digital display that shows 12.04mV for a sample of moisture content of 6%.
Example 6
A non-porous Barium titanate substrate of thickness 4mm is taken. Silver flakes and metallic Palladium was mixed in requisite quantities with acetone and then dried. The dried powder was then made into a paste of desired viscosity by mixing with thinner and organic vehicle consisting of binder, solvent, plasticizer and homogenizer. The prepared conductive paste was screen printed onto the porous ceramic material using silk screen printing technique. Circular electrode 10 in numbers are printed by the prepared thick film paste with thickness of 30um width of 1mm and interelectrode gap of 0.6mm are printed were dried and fired at temperature of 850°C for 60min. The alternate electrodes are connected to two terminals of a tuned circuit that measures the power factor of the sample. The output of the tuned circuit is

converted to DC voltage and the final output is connected to an analog or digital display that shows 11.35mV for a sample of moisture content of 5.5%.
The main advantages of the present invention are:
1. High sensitivity from 0-20% moisture level
2. Fast response ( 3. Temperature stability over the range.
4. Not sensitive to electrical noise.
5. Practically no drift over time.
6. Low cost compared to conventional sensor available in the market.
7. The sensor can be used continuously for a long period of time.

We Claim:
1. A novel sensor for the determination of moisture in agricultural produce which
comprises a noriporous ceramic substrate characterized in that the said
substrate having dielectric constant within 100, the said substrate being
provided with a plurality of thick film planar electrodes of thickness in the
range 20-30µm, width in the range of 1-2 mm and interelectrode gap in the
range of 0.5-1.0 mm, the said planar electrodes being connected to two
terminals in an alternate manner.
2. a novel sensor as claimed in Claim 1 wherein the said ceramic substrate used
selected from Barium titan ate, Alumina, Zirconia, Yuttria stabilized zirconia
or Magnesia.
3. A novel sensor as claimed in Claims 1-2 wherein the thickness of the non-
porous substrate is in the range of 3-5 mm.
4. A novel sensor as claimed in Claims 1 -3 wherein the pore size of then on-
porous ceramic substrate is within 0.1 µm.
5. A novel sensor as claimed in Claims 1-4 wherein the electrodes are made of
Ag-Pd or Ag thick film paste.
6. A moisture sensing device for measuring moisture in agricultural produce
which comprises a novel moisture sensor as claimed in Claims 1-5 being
connected to a conventional tuned circuit, the output of the said tuned circuit
being converted to dc by conventional means and the resultant output being
connected to an analog or digital display.
7. A novel sensor for the determination of moisture in agricultural produce
substantially as herein described with reference to the examples.

Documents:

528-del-2001-abstract.pdf

528-del-2001-claims.pdf

528-del-2001-correspondence-others.pdf

528-del-2001-correspondence-po.pdf

528-del-2001-description (complete).pdf

528-del-2001-form-1.pdf

528-del-2001-form-18.pdf

528-del-2001-form-2.pdf

528-del-2001-form-3.pdf

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Patent Number

230366

Indian Patent Application Number

528/DEL/2001

PG Journal Number

11/2009

Publication Date

13-Mar-2009

Grant Date

26-Feb-2009

Date of Filing

26-Apr-2001

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH,

Applicant Address

RAFI MARG, NEW DELHI-110 001,

Inventors:

#	Inventor's Name	Inventor's Address
1	SUMAN CHATTERJEE,	FROM CENTRAL GLASS & CERAMIC RESEARCH INTITUTE, CALCUTTA 700 032,
2	SANTANU BASU,	India Karnataka India
3	KAMALENDU SENGUPTA	India Karnataka India
4	KALYAN KUMAR MISTRY	India Karnataka India

PCT International Classification Number

A01D

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA