CN105758892A - Device for measurement of green sand moisture content by separation resistance and moisture content acquisition method - Google Patents

Device for measurement of green sand moisture content by separation resistance and moisture content acquisition method Download PDF

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Publication number
CN105758892A
CN105758892A CN201610123773.8A CN201610123773A CN105758892A CN 105758892 A CN105758892 A CN 105758892A CN 201610123773 A CN201610123773 A CN 201610123773A CN 105758892 A CN105758892 A CN 105758892A
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China
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signal
unit
resistance
green
sand
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CN201610123773.8A
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Inventor
石德全
康凯娇
高桂丽
李大勇
陈志俊
王傲
裴立新
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Harbin University of Science and Technology
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Harbin University of Science and Technology
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Priority to CN201610123773.8A priority Critical patent/CN105758892A/en
Publication of CN105758892A publication Critical patent/CN105758892A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/048—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance for determining moisture content of the material

Abstract

Relating to the field of casting detection, the invention provides a device for measurement of green sand moisture content by separation resistance and a moisture content acquisition method, and solves the problem of low test precision caused by capacitive component influence during green sand moisture content measurement by a traditional resistance method green sand moisture content measurement device. The device consists of a green sand equivalent circuit, a signal conditioning unit, a sine wave excitation signal generation unit, a zero-crossing comparative unit, a switch unit, a signal separation unit, an average value detection unit, an A/D conversion unit, a communication unit and a computer. By means of the zero-crossing comparative unit, a square-wave signal with the same frequency and phase to a sine wave excitation signal can be obtained, under the action of the square-wave signal, the imaginary parts of signal separation unit's output voltage offset each other in positive and negative half-cycles, and the average value is zero, while the real part is introduced into the average value detection unit so as to obtain an average voltage value only associated with resistance, and the influence of the capacitive component can be eliminated. The resistance value of green sand can be calculated according to a formula, and then the green sand moisture content can be acquired.

Description

Separate device and the water content acquisition methods of resistance measurement green sand moisture
Technical field
The present invention relates to casting detection field, specifically a kind of device separating resistance measurement green sand moisture and water content acquisition methods.
Background technology
Water content is the important component parameter of green-sand, the performance of the change direct relation green-sand of water content, and then affects the quality of foundry goods, therefore, measures green sand moisture fast and accurately most important.At present, develop the measuring method of nearly ten kinds of green sand moisture, wherein electric-resistivity method is one of green sand moisture method for fast measuring of being widely used, its ultimate principle is under alternating current source incentive action, the change of resistance value can be caused during change of moisture content according to tested green-sand, by recording the resistance value of green-sand, calculate the size of water content further according to the existing relation between water content and the resistance value of green-sand.Under ac-excited, although reducing the green-sand polarization impact on measurement result, but green-sand under electric field action except showing resistance characteristic, there is also capacitance characteristic simultaneously, and capacitive component is often ignored by traditional electric-resistivity method at measurement green sand moisture, so greatly reduce the measuring accuracy of resistance measurement green sand moisture.
Summary of the invention
The present invention is to solve that traditional resistor method green sand moisture measurement apparatus is when measuring green sand moisture, the problem that measuring accuracy is not high is caused, it is provided that a kind of device separating resistance measurement green sand moisture and water content acquisition methods owing to being affected by capacitive component.
nullSeparate the device of resistance measurement green sand moisture，It includes green-sand equivalent circuit、Signal conditioning unit、Sine wave exciting signal generation unit、Zero-cross comparator unit、Switch element、Signal separation unit、Average detection unit、A/D converting unit、Communication unit and computer，The signal output part of green-sand equivalent circuit is connected with signal conditioning unit signal input part，The other end ground connection of green-sand equivalent circuit，The signal output part of signal conditioning unit is connected with signal separation unit signal input part，The signal output part of signal separation unit is connected with the signal input part of average detection unit，The signal output part of average detection unit is connected with the signal input part of A/D converting unit，The signal output part of A/D converting unit is connected with the signal input part of communication unit，The signal output part of communication unit is connected with the signal input part of computer，The signal output part of sine wave exciting signal generation unit is connected with another signal input part of signal conditioning unit、It is connected with the signal input part of Zero-cross comparator unit simultaneously，The signal output part of Zero-cross comparator unit is connected with the signal input part of switch element，The signal output part of switch element is connected with another signal input part of signal separation unit.
Described green-sand equivalent circuit is by green-sand equivalent resistance RxWith green-sand equivalent capacity CxComposing in parallel, described signal conditioning unit is by amplifier AI, feedback resistance Rf1With balancing resistance R1Composition, described signal separation unit is by amplifier AII, feedback resistance Rf2, inverting input resistance R2With in-phase input end resistance R3Composition, described amplifier AIInverting input and feedback resistance Rf1One end be connected, be connected with the signal output part of green-sand equivalent circuit simultaneously, amplifier AIIn-phase input end and balancing resistance R1One end be connected, balancing resistance R1The other end be connected with the signal output part of sine wave exciting signal generation unit, amplifier AIOutfan and feedback resistance Rf1The other end be connected, amplifier AIIInverting input and feedback resistance Rf2One end be connected, simultaneously with inverting input resistance R2One end be connected, amplifier AIIIn-phase input end and in-phase input end resistance R3One end be connected, be connected with the signal output part of switch element simultaneously, amplifier AIIOutfan and feedback resistance Rf2The other end be connected, be connected with the signal input part of average detection unit simultaneously, inverting input resistance R2The other end and in-phase input end resistance R3The other end be connected.
Described feedback resistance Rf2, inverting input resistance R2With in-phase input end resistance R3Resistance equal.
The described water content acquisition methods based on the device separating resistance measurement green sand moisture comprises the following steps:
Step one, being arranged in measurement apparatus by green-sand sand sample, green-sand equivalent circuit accesses in the device separating resistance measurement green sand moisture；
It is ω, amplitude is U that step 2, sine wave exciting signal generation unit produce frequencyimSine wave exciting signal Ui=UimSin ω t, and it is applied simultaneously to signal conditioning unit and the signal input part of Zero-cross comparator unit；
Step 3, signal conditioning unit output voltage
The output of step 4, Zero-cross comparator unit and sine wave exciting signal UiSame frequency, synchronous square-wave signal, and it is applied to the signal input part of switch element；
Step 5, when Zero-cross comparator unit 4 output square-wave signal be high level time, the signal output part of switch element with ground disconnect, signal separation unit output voltage, when the square-wave signal of Zero-cross comparator unit output is low level, the signal output part of switch element is connected with ground, signal separation unit output voltage, within a cycle, the imaginary part of the output voltage sum of synchronous separating unit is cancelled out each other in positive-negative half-cycle, and meansigma methods is zero；
Step 5, synchronous separating unit output voltageAccessing the signal input part of average detection unit 7, average detection unit produces DC signal output Ux, then deliver to A/D converting unit and sample, and send in computer through communication unit；
Step 6, computer are according to formulaTry to achieve the resistance value of green-sand, further according to existing green-sand resistance RxAnd the relation between water content, can try to achieve the water content of green-sand.
Advantages of the present invention: obtained and sinusoidal excitation signal same frequency, synchronous square-wave signal by Zero-cross comparator unit, under square-wave signal effect, the imaginary part of the output voltage of signal separation unit is cancelled out each other in positive-negative half-cycle, meansigma methods is zero, and real part accesses average detection unit, obtains only relevant to resistance average voltage, and then try to achieve the resistance value of green-sand, eliminate the impact of capacitive component, then try to achieve the water content of green-sand, substantially increase the certainty of measurement of green sand moisture.
Accompanying drawing explanation
Fig. 1 is the formation picture of device separating resistance measurement green sand moisture in the present invention.
Detailed description of the invention
nullDetailed description of the invention one: present embodiment is described in conjunction with Fig. 1，The device separating resistance measurement green sand moisture described in present embodiment，It includes green-sand equivalent circuit 1、Signal conditioning unit 2、Sine wave exciting signal generation unit 3、Zero-cross comparator unit 4、Switch element 5、Signal separation unit 6、Average detection unit 7、A/D converting unit 8、Communication unit 9 and computer 10，The signal output part of green-sand equivalent circuit 1 is connected with a signal input part of signal conditioning unit 2，The other end ground connection of green-sand equivalent circuit 1，The signal output part of signal conditioning unit 2 is connected with a signal input part of signal separation unit 6，The signal output part of signal separation unit 6 is connected with the signal input part of average detection unit 7，The signal output part of average detection unit 7 is connected with the signal input part of A/D converting unit 8，The signal output part of A/D converting unit 8 is connected with the signal input part of communication unit 9，The signal output part of communication unit 9 is connected with the signal input part of computer 10，The signal output part of sine wave exciting signal generation unit 3 is connected with another signal input part of signal conditioning unit 2、It is connected with the signal input part of Zero-cross comparator unit 4 simultaneously，The signal output part of Zero-cross comparator unit 4 is connected with the signal input part of switch element 5，The signal output part of switch element 5 is connected with another signal input part of signal separation unit 6.
Detailed description of the invention two: illustrating that present embodiment, present embodiment are progress one explanations to detailed description of the invention one in conjunction with Fig. 1, the green-sand equivalent circuit 1 described in present embodiment is by green-sand equivalent resistance RxWith green-sand equivalent capacity CxComposing in parallel, described signal conditioning unit 2 is by amplifier AI, feedback resistance Rf1With balancing resistance R1Composition, described signal separation unit 6 is by amplifier AII, feedback resistance Rf2, inverting input resistance R2With in-phase input end resistance R3Composition, described amplifier AIInverting input and feedback resistance Rf1One end be connected, be connected with the signal output part of green-sand equivalent circuit 1 simultaneously, amplifier AIIn-phase input end and balancing resistance R1One end be connected, balancing resistance R1The other end be connected with the signal output part of sine wave exciting signal generation unit 3, amplifier AIOutfan and feedback resistance Rf1The other end be connected, amplifier AIIInverting input and feedback resistance Rf2One end be connected, simultaneously with inverting input resistance R2One end be connected, amplifier AIIIn-phase input end and in-phase input end resistance R3One end be connected, be connected with the signal output part of switch element 5 simultaneously, amplifier AIIOutfan and feedback resistance Rf2The other end be connected, be connected with the signal input part of average detection unit 7 simultaneously, inverting input resistance R2The other end and in-phase input end resistance R3The other end be connected.
Detailed description of the invention three: illustrate that present embodiment, present embodiment are progress one explanations to detailed description of the invention two in conjunction with Fig. 1, the feedback resistance R described in present embodimentf2, inverting input resistance R2With in-phase input end resistance R3Resistance equal.
Detailed description of the invention four: present embodiment is described in conjunction with Fig. 1, present embodiment is progress one explanation to detailed description of the invention three, and the water content acquisition methods based on the device separating resistance measurement green sand moisture described in present embodiment comprises the following steps:
Step one, being arranged in measurement apparatus by green-sand sand sample, green-sand equivalent circuit 1 accesses in the device separating resistance measurement green sand moisture；
It is ω, amplitude is U that step 2, sine wave exciting signal generation unit 3 produce frequencyimSine wave exciting signal Ui=UimSin ω t, and it is applied simultaneously to signal conditioning unit 2 and the signal input part of Zero-cross comparator unit 4；
Step 3, signal conditioning unit 2 output voltage
The output of step 4, Zero-cross comparator unit 4 and sine wave exciting signal UiSame frequency, synchronous square-wave signal, and it is applied to the signal input part of switch element 5；
Step 5, when Zero-cross comparator unit 4 output square-wave signal be high level time, the signal output part of switch element 5 with ground disconnect, signal separation unit 6 output voltage, when the square-wave signal of Zero-cross comparator unit 4 output is low level, the signal output part of switch element 5 is connected with ground, signal separation unit 6 output voltage, within a cycle, the output voltage of synchronous separating unit 6Imaginary part cancel out each other in positive-negative half-cycle, meansigma methods is zero；
Step 5, synchronous separating unit 6 output voltageAccessing the signal input part of average detection unit 7, average detection unit 7 produces DC signal output Ux, then deliver to A/D converting unit 8 and sample, and send in computer 10 through communication unit 9；
Step 6, computer 10 are according to formulaTry to achieve the resistance value of green-sand, further according to existing green-sand resistance RxAnd the relation between water content, can try to achieve the water content of green-sand.

Claims (4)

  1. null1. separate the device of resistance measurement green sand moisture，It is characterized in that，It includes green-sand equivalent circuit (1)、Signal conditioning unit (2)、Sine wave exciting signal generation unit (3)、Zero-cross comparator unit (4)、Switch element (5)、Signal separation unit (6)、Average detection unit (7)、A/D converting unit (8)、Communication unit (9) and computer (10)，The signal output part of green-sand equivalent circuit (1) is connected with a signal input part of signal conditioning unit (2)，The other end ground connection of green-sand equivalent circuit (1)，The signal output part of signal conditioning unit (2) is connected with a signal input part of signal separation unit (6)，The signal output part of signal separation unit (6) is connected with the signal input part of average detection unit (7)，The signal output part of average detection unit (7) is connected with the signal input part of A/D converting unit (8)，The signal output part of A/D converting unit (8) is connected with the signal input part of communication unit (9)，The signal output part of communication unit (9) is connected with the signal input part of computer (10)，The signal output part of sine wave exciting signal generation unit (3) is connected with another signal input part of signal conditioning unit (2)、It is connected with the signal input part of Zero-cross comparator unit (4) simultaneously，The signal output part of Zero-cross comparator unit (4) is connected with the signal input part of switch element (5)，The signal output part of switch element (5) is connected with another signal input part of signal separation unit (6).
  2. 2. the device of separation resistance measurement green sand moisture according to claim 1, it is characterised in that described green-sand equivalent circuit (1) is by green-sand equivalent resistance RxWith green-sand equivalent capacity CxComposing in parallel, described signal conditioning unit (2) is by amplifier AI, feedback resistance Rf1With balancing resistance R1Composition, described signal separation unit (6) is by amplifier AII, feedback resistance Rf2, inverting input resistance R2With in-phase input end resistance R3Composition, described amplifier AIInverting input and feedback resistance Rf1One end be connected, be connected with the signal output part of green-sand equivalent circuit (1) simultaneously, amplifier AIIn-phase input end and balancing resistance R1One end be connected, balancing resistance R1The other end be connected with the signal output part of sine wave exciting signal generation unit (3), amplifier AIOutfan and feedback resistance Rf1The other end be connected, amplifier AIIInverting input and feedback resistance Rf2One end be connected, simultaneously with inverting input resistance R2One end be connected, amplifier AIIIn-phase input end and in-phase input end resistance R3One end be connected, be connected with the signal output part of switch element (5) simultaneously, amplifier AIIOutfan and feedback resistance Rf2The other end be connected, be connected with the signal input part of average detection unit (7) simultaneously, inverting input resistance R2The other end and in-phase input end resistance R3The other end be connected.
  3. 3. the device of separation resistance measurement green sand moisture according to claim 2, it is characterised in that described feedback resistance Rf2, inverting input resistance R2With in-phase input end resistance R3Resistance equal.
  4. 4. based on the device separating resistance measurement green sand moisture described in claims 1 to 3, it is characterised in that the water content acquisition methods based on the device separating resistance measurement green sand moisture comprises the following steps:
    Step one, being arranged in measurement apparatus by green-sand sand sample, green-sand equivalent circuit (1) accesses in the device separating resistance measurement green sand moisture；
    It is ω, amplitude is U that step 2, sine wave exciting signal generation unit (3) produce frequencyimSine wave exciting signal Ui=UimSin ω t, and it is applied simultaneously to signal conditioning unit (2) and the signal input part of Zero-cross comparator unit (4)；
    Step 3, signal conditioning unit (2) output voltage；
    The output of step 4, Zero-cross comparator unit (4) and sine wave exciting signal UiSame frequency, synchronous square-wave signal, and it is applied to the signal input part of switch element (5)；
    Step 5, when the square-wave signal that Zero-cross comparator unit (4) exports is high level, the signal output part of switch element (5) with ground disconnect, signal separation unit (6) output voltage, when the square-wave signal that Zero-cross comparator unit (4) exports is low level, the signal output part of switch element (5) is connected with ground, signal separation unit (6) output voltage, within a cycle, the imaginary part of the output voltage sum of synchronous separating unit (6) is cancelled out each other in positive-negative half-cycle, and meansigma methods is zero；
    Step 6, synchronous separating unit (6) output voltage and access average detection unit (7) signal input part, average detection unit (7) produce DC signal output Ux, then deliver to A/D converting unit (8) and sample, and send in computer (10) through communication unit (9)；
    Step 7, computer (10) are according to formulaTry to achieve the resistance value of green-sand, further according to existing green-sand resistance RxAnd the relation between water content, can try to achieve the water content of green-sand.
CN201610123773.8A 2016-03-05 2016-03-05 Device for measurement of green sand moisture content by separation resistance and moisture content acquisition method Pending CN105758892A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106404845A (en) * 2016-09-13 2017-02-15 山东铁正工程试验检测中心有限公司 Rapid determination device for water content of roadbed filler

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5928646A (en) * 1982-08-11 1984-02-15 Kao Corp Method and device for measuring moisture content of skin
CN2580438Y (en) * 2002-04-29 2003-10-15 长春工业大学 Electrical conductivity measurer
CN102998160A (en) * 2012-12-31 2013-03-27 哈尔滨理工大学 Cylindrical sample preparation device for measuring moisture content of green sand through capacitance method and method for measuring moisture content of green sand
CN103308589A (en) * 2013-06-26 2013-09-18 哈尔滨理工大学 Testing method of polarization performance of wet type clay sand

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5928646A (en) * 1982-08-11 1984-02-15 Kao Corp Method and device for measuring moisture content of skin
CN2580438Y (en) * 2002-04-29 2003-10-15 长春工业大学 Electrical conductivity measurer
CN102998160A (en) * 2012-12-31 2013-03-27 哈尔滨理工大学 Cylindrical sample preparation device for measuring moisture content of green sand through capacitance method and method for measuring moisture content of green sand
CN103308589A (en) * 2013-06-26 2013-09-18 哈尔滨理工大学 Testing method of polarization performance of wet type clay sand

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
张宏邦 等: "陶瓷物料水分快速检测的复阻抗分离法探讨", 《中国陶瓷工业》 *
张志良: "《数字电子技术基础》", 31 July 2007 *
张邦宏: "陶瓷泥料水分电容传感器电路分析", 《陶瓷学报》 *
蔡志端: "基于复阻抗分离法的电容式水分测量系统研究", 《中国优秀硕士学位论文全文数据库（电子期刊）信息科技辑》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106404845A (en) * 2016-09-13 2017-02-15 山东铁正工程试验检测中心有限公司 Rapid determination device for water content of roadbed filler

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