CN106401989A - Centrifugal pump cavitation monitoring device - Google Patents
Centrifugal pump cavitation monitoring device Download PDFInfo
- Publication number
- CN106401989A CN106401989A CN201610915044.6A CN201610915044A CN106401989A CN 106401989 A CN106401989 A CN 106401989A CN 201610915044 A CN201610915044 A CN 201610915044A CN 106401989 A CN106401989 A CN 106401989A
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- Prior art keywords
- cavitation
- signal
- microprocessor
- receiving
- centrifugal pump
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
- F04D15/0088—Testing machines
Abstract
The invention discloses a centrifugal pump cavitation monitoring device which comprises a plurality of cavitation monitoring units, an amplifier, an A/D converter, a microprocessor and an output unit. The cavitation monitoring units are ultrasonic transducers; and each ultrasonic transducer comprises a transmitting terminal with the power smaller than 10w, and a receiving terminal matched with the transmitting terminal, wherein the receiving terminal is used for receiving ultrasonic signals from the transmitting terminal and converting the received ultrasonic signals into sonic analog signals. The amplifier is used for receiving and amplifying the sonic analog signals. The A/D converter is used for converting the amplified primary analog signals into sonic digital signals. The microprocessor is used for receiving and judging the sonic digital signals from the A/D converter, and outputting corresponding feedback signals. The output unit is controlled by the microprocessor and displays the received feedback signals. By adoption of the centrifugal pump cavitation monitoring device, cavitation inception can be better predicted, the whole cavitation process can be monitored in real time, the device can automatically adapt to signal variation caused by factors including environment temperatures, installing differences and the like, and misdeclaration is avoided.
Description
Technical field
The present invention relates to a kind of monitoring device, especially a kind of centrifugal pump cavitation monitoring device.
Background technology
When cavitation refers to below the critical pressure for vaporization of the reduced pressure in liquid to Current Temperatures, liquid vaporizes
Form cavity, the state of these vacuolizations and development is referred to as cavitation.In centrifugal pump, cavitation phenomenon is concentrated mainly on leaf
Impeller blade entrance, when cavitation occurs, the energy exchange of liquid is interfered and destroys, and causes pump operation characteristic changing, vibration to make an uproar
A series of problems, such as sound, material corrosion, structural deterioration, pump liquid stream when serious, can be made to interrupt it is impossible to normal work.Therefore to centrifugation
In pump, the grasp of cavitation situation is significant to the safe and stable, Effec-tive Function of pump, and is based on ultrasonic sensor monitoring
Centrifugation pump cavitation situation is a kind of effective method.
Existing monitoring centrifugal pump cavitation inception method mainly have noise measuring method, tonometry, vibration measurement method and
High Speed Photography.Due to cavitation occur development process very short, and in whole working range all it may happen that, therefore cavitation
It is difficult to prediction.Pre- anti-cavitation best bet is exactly to set up cavitation monitoring system, carries out whole real-time monitoring to its running status,
Find and prevent the occurrence and development of cavitation in time.Lot of domestic and international scholar has carried out substantial amounts of research to the monitoring of cavitation, but
Its object of study mostly concentrates on hydraulic turbine model and its prototype, and monitoring method also with High Speed Photography and vibratory drilling method is mainly
Main.
The cavitation performance context of detection of pump, domestic and international method is a lot, mainly has vibratory drilling method, electrical measuring method, pressure pulsation method, energy
Mensuration and Noise Method etc..Although existing on-line detecting system puts into commercial Application, because cavitation signal extraction difficulty is big, detection
Sensitivity is low, lack the deficiency such as quantitative analyses so that these achievements in research are not promoted on a large scale.Existing online inspection
Mechanism, influence factor and destruction that examining system occurs to cavitation are not all understood completely, but also can not accurately detect
To cavitation inception.
Content of the invention
In order to overcome the deficiencies in the prior art, the invention provides a kind of preferably predict cavitation inception, to cavitation processes
Carry out whole real-time monitoring, thus can find according to monitoring result and prevent the centrifugation pump cavitation of cavitation occurrence and development from supervising in time
Survey device.
The technical solution adopted for the present invention to solve the technical problems is：A kind of centrifugal pump cavitation monitoring device, including：
Some cavitation monitoring units, this cavitation monitoring unit is ultrasonic transducer, and this ultrasonic transducer includes active
Rate is less than the transmitting terminal of 10w and the receiving terminal matching with transmitting terminal, and this receiving terminal is used for receiving super from transmitting extreme direction
Acoustic signals and received ultrasonic signal is converted into sound wave analogue signal；
Amplifier, amplifies sound wave analogue signal for receiving；
A/D converter, for being converted into sound wave digital signal by the primary analogue signal after amplifying；
Microprocessor, for receiving the sound wave digital signal judging to be derived from A/D converter and exporting corresponding feedback letter
Number；
Output unit, is controlled by microprocessor and shows received feedback signal.
The invention has the beneficial effects as follows：Make the function of traditional sensors be expanded to by conventional " infomation detection " effect to have concurrently
The function of " information processing ", transmitting terminal and receiving terminal are satisfied with pump conduit respectively, gather signal using ultrasound wave receiving terminal, and fit
Give after amplifying and there is A/D conversion and the microprocessor of data-handling capacity realizes digital filtering, fuzzy diagnosis and resolution
Select etc., it can automatically adapt to ambient temperature, install the signal intensity that the factors such as difference lead to, it is to avoid wrong report.Why select
Ultrasonic transducer, is because that ultrasound wave is very big to the penetrating power of liquid, solid, and when encountering impurity or separating surface can produce
Notable reflection, the signal that correspondingly ultrasound wave receiving terminal receives just substantially weakens, therefore reaction is sensitive accurately, reduces and judges by accident.Separately
Outward, with respect to the performance of infrared sensor, ultrasound wave has that frequency is high, wavelength is short, diffraction phenomenon is little, particularly good directionality,
Ray can be become and the features such as direction propagation.Because, in tradition application, ultrasound wave is for producing one of trigger of cavitation,
Common purposes is to reach the function of object surface cleaning by cavitation, therefore, no one will recognize that, also cannot use ultrasound wave
Go to monitor the enlightenment of Hollow fluid situation.Why the present invention can reach cavitation monitoring using ultrasound wave, is because applicant
Obtained by theory analysis and practical operation, when the power of the transmitting terminal of ultrasonic transducer is less than 10w, fluid can't be because of
The presence of ultrasound wave and produce ultrasonic cavitation, therefore, take reasonable power bracket to be exactly to enable to monitor, and concrete power be such as
What choose, depending on the material of institute's installation pipeline, thickness, fluid composition, viscosity etc. it is only necessary to be adjusted according to environment be
Can, have no effect on the realization of the object of the invention.
It is preset with the threshold signal of cavitation in conventional conduit in microprocessor, also include：Timing unit, is used for recording each sky
Change monitoring means to sense time during cavity and pass through connection with microprocessor；Comparison unit, is used for comparing sound wave number
The energy size of word signal and threshold signal simultaneously will exceed the sound wave digital data transmission of threshold signal energy to microprocessor.
Timing unit monitors cavity change in flow, and unit has bubbly flow situation with liquid in normal pipeline and is compared by contrast,
Thus monitoring cavitation development.Wherein, timing unit mainly senses the time difference of cavity, phase by each cavitation monitoring unit
The change showing cavity flow velocity answered, the change of pump conduit flow equally reflects the development of cavitation indirectly；Comparison unit will just
The threshold values of Chang Guanlu cavitation is contrasted with sound wave digital signal, thus more in depth reflection cavitation development.
Centrifugal pump cavitation monitoring device also includes：Sensitivity adjusting unit, for adjust described threshold signal size and
Pass through connection with microprocessor.For different pump conduit, need to adjust the threshold of sensitivity (i.e. threshold signal) of cavity,
Monitoring cavitation is controlled to produce scope.Main Means are that the size producing cavity in liquid can directly cause the low electricity of comparator output terminal
The change of flat persistent period, adjusts the spilling time that divide ratio just can change enumerator, also just can adjust the cavity threshold of sensitivity
Value.
Centrifugal pump cavitation monitoring device also includes monitoring pipeline, each ultrasonic transducer along monitoring pipe lengths according to
Secondary arrangement, and the transmitting terminal of ultrasonic transducer and receiving terminal are accordingly installed on the week side of boss of monitoring pipeline.Due to pipeline surface
Situation is each different, in order to improve precision and the accuracy of monitoring, so that centrifugal pump cavitation monitoring device comes with monitoring pipe
Road is it is only necessary to be serially connected with monitoring pipeline in pump conduit.So operate, can avoid because different pipeline material and thickness
, so that more convenient to operate, accuracy is also higher for the adjustment difficulty increasing threshold signal.
Further preferably scheme：The power of transmitting terminal is 5w.Both can ensure that
Brief description
Fig. 1 is the system block diagram of the embodiment of the present invention.
Fig. 2 is the sensitivity adjusting unit of the embodiment of the present invention.
Specific embodiment
The invention will be further described below in conjunction with the accompanying drawings：
As shown in figure 1, the present embodiment includes microprocessor 1, some cavitation monitoring units, amplifier 31, A/D converter 32
With output unit (not shown).Cavitation monitoring unit is ultrasonic transducer, and it is 5w's that this ultrasonic transducer 2 includes power
Transmitting terminal 21 and the receiving terminal 22 matching with transmitting terminal 21, this receiving terminal 22 is used for receiving surpassing from transmitting terminal 21 direction
Acoustic signals and received ultrasonic signal is converted into sound wave analogue signal；Amplifier 31 is used for receiving amplification sound wave
Analogue signal；A/D converter 32 is used for for the primary analogue signal after amplifying being converted into sound wave digital signal；Microprocessor 1 is used
From the sound wave digital signal of A/D converter 32 and export corresponding feedback signal in receiving judgement.Output unit is controlled by micro-
Processor 1 simultaneously shows received feedback signal, this output unit 1 can using display or collection of illustrative plates printer etc. other
What enables the equipment of information output.Microprocessor can be single-chip microcomputer, can be using Japanese NEC8 position High Performance SCM NEC
78K0/Kx1+ series；Or other any microcomputers with calculating processing function.
It is preset with the threshold signal of cavitation in conventional conduit, the present embodiment also includes timing unit 41 He in microprocessor 1
Comparison unit 42, timing unit 41 is used for recording each cavitation monitoring unit and senses time during cavity and led to microprocessor 1
Cross connection；Comparison unit 42 is for comparing the energy size of sound wave digital signal and threshold signal and will exceed threshold values letter
The sound wave digital data transmission of number energy is to microprocessor 1.Timing unit 41 monitors cavity change in flow, by contrast unit 42 with
In normal pipeline there is bubbly flow situation and be compared, thus monitoring cavitation development in liquid.Wherein, timing unit 41 is main
To sense the time difference of cavity by each cavitation monitoring unit, show the change of cavity flow velocity, pump conduit flow accordingly
Change equally indirectly reflect cavitation development；The threshold values of normal pipeline cavitation and sound wave digital signal are entered by comparison unit 42
Row contrast, thus more in depth reflection cavitation development.D.C. regulated power supply is that ultrasonic transducer provides energy, according to originally connecing
It is just much of that the feature of receiving end only needs to about tens volts of voltages, typically can select the limit within safe voltage, in selecting circuit
Leakage resistance, in order to limit ultrasonic energy, pulse-generating circuit produces certain frequency square wave, supply waveform conversion and driving electricity
Road, pulse frequency here should be consistent with the resonant frequency of piezoelectric chip, when the frequency being added to two ends alternating voltage and chip
Resonant frequency equal when, the energy of output is maximum, sensitivity also highest.Receive and use in ultrasonic transducer 2, receiving terminal 22
Resonant frequency should be consistent with transmitting terminal 21, and it receives from the ultrasound wave decayed through after tube wall, air-gap and liquid
Signal, this signal is fainter, gives the comparator chip of high input impedance, warp and reference voltage after diode double limiting
Relatively produce pulse signal, to identify in liquid whether be mixed with bubble.
The present embodiment also includes sensitivity adjusting unit 5, and this sensitivity adjusting unit 5 is used for adjusting threshold signal big
Little and with microprocessor 1 pass through connection.For different pump conduit, need to adjust the threshold of sensitivity (the i.e. threshold values of cavity
Signal), control monitoring cavitation to produce scope.Main Means are that the size producing cavity in liquid can directly cause comparator to export
The change of end low duration, adjusts the spilling time that divide ratio just can change enumerator, also just can adjust cavity spirit
Sensitivity threshold value.As shown in Fig. 2 sensitivity adjusting unit 5 is sensitivity adjusting circuit, clock oscillation 51 in sensitivity adjusting circuit
Circuit produces clock signal, delivers to the clock end of binary addition impulse scaler after programmable frequency divider, and ultrasound wave inspection
Survey 52 electric circuit inspection to ultrasonic pulse signal be added in this impulse scaler " clearing " end.It is mixed into single cavity in liquid
Size can directly cause the change of comparator output terminal low duration, and the divide ratio adjusting programmable frequency divider is with regard to energy
Change up counter and overflow the time, also just can adjust sensitivity of the level threshold value, control the scope that monitoring cavitation inception produces.Have
Can also be reported to the police by triggering 55 circuit of reporting to the police when needs.
In order to improve monitoring accuracy and accuracy, it is to avoid because different pipeline material and thickness increase the adjustment of threshold signal
Difficulty, the present embodiment also includes monitoring pipeline 6, and each ultrasonic transducer 2 is arranged successively along monitoring pipe lengths, and super
The transmitting terminal 21 of acoustic wave transducer 2 and receiving terminal 22 are accordingly installed on the week side of boss monitoring pipeline 6.
In the present invention, so that the function of ultrasonic sensor is expanded to by conventional " infomation detection " effect and have " information concurrently
The function of reason ", this is its maximum feature.In addition, being different from other detection modes, it belongs to non-contact type detection, to experiment
Affect less, the accuracy of Enhancement test result.Transmitting terminal 21 and receiving terminal 22 are satisfied with pump conduit respectively, are connect using ultrasound wave
Receiving end 22 gather signal, and suitably amplify after give have A/D conversion and data-handling capacity microprocessor 1 realize numeral filter
Ripple, fuzzy diagnosis and resolution selection etc., it can automatically adapt to ambient temperature, install the signal intensity that the factors such as difference lead to,
Avoid reporting by mistake.Why select ultrasonic transducer, be because that ultrasound wave is very big to the penetrating power of liquid, solid, and ought touch
Notable reflection can be produced to impurity or separating surface, the signal that correspondingly ultrasound wave receiving terminal 22 receives just substantially weakens, therefore instead
Should be sensitive accurate, reduce erroneous judgement.Additionally, producing working pulse by using timer internal, expansion bus realize data exchange
Etc. technology, it is possible to reduce other peripheral chip usage amounts, the volume that reduces, the cost performance that improves, enhancing capacity of resisting disturbance, using the party
Method can prevent the cavitation inception of centrifugal pump in advance.
Claims (5)
1. a kind of centrifugal pump cavitation monitoring device, is characterized in that, including：
Some cavitation monitoring units, this cavitation monitoring unit is ultrasonic transducer, and it is little that this ultrasonic transducer includes power
The receiving terminal match in the transmitting terminal of 10w and with transmitting terminal, this receiving terminal is used for receiving the ultrasound wave from transmitting extreme direction
Signal and received ultrasonic signal is converted into sound wave analogue signal；
Amplifier, amplifies sound wave analogue signal for receiving；
A/D converter, for being converted into sound wave digital signal by the primary analogue signal after amplifying；
Microprocessor, for receiving the sound wave digital signal judging to be derived from A/D converter and exporting corresponding feedback signal；
Output unit, is controlled by microprocessor and shows received feedback signal.
2. centrifugal pump cavitation monitoring device according to claim 1, is characterized in that, be preset with routine in described microprocessor
In pipeline, the threshold signal of cavitation, also includes：
Timing unit, senses time during cavity and with microprocessor by circuit even for recording each cavitation monitoring unit
Connect；
Comparison unit, for comparing the energy size of sound wave digital signal and threshold signal and exceeding threshold signal energy
Sound wave digital data transmission is to microprocessor.
3. centrifugal pump cavitation monitoring device according to claim 2, is characterized in that, also include：
Sensitivity adjusting unit, for adjusting described threshold signal size and with microprocessor by connection.
4. centrifugal pump cavitation monitoring device according to claim 1, is characterized in that：Also include monitoring pipeline, each ultrasonic
Wave transducer is arranged successively along monitoring pipe lengths, and the transmitting terminal of ultrasonic transducer and receiving terminal are accordingly installed on
The week side of boss of monitoring pipeline.
5. centrifugal pump cavitation monitoring device according to claim 1, is characterized in that：The power of described transmitting terminal is 5w.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610915044.6A CN106401989B (en) | 2016-10-20 | 2016-10-20 | A kind of centrifugal pump cavitation monitoring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610915044.6A CN106401989B (en) | 2016-10-20 | 2016-10-20 | A kind of centrifugal pump cavitation monitoring device |
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| CN106401989A true CN106401989A (en) | 2017-02-15 |
| CN106401989B CN106401989B (en) | 2017-11-14 |
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| CN201610915044.6A Active CN106401989B (en) | 2016-10-20 | 2016-10-20 | A kind of centrifugal pump cavitation monitoring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108895018A (en) * | 2018-04-20 | 2018-11-27 | 浙江理工大学 | A kind of device and method monitoring the development process of centrifugal blade cavitation |
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| JP2010249637A (en) * | 2009-04-15 | 2010-11-04 | Yokogawa Electric Corp | Method for detecting state of fluid and state detecting device |
| CN102033106A (en) * | 2010-11-12 | 2011-04-27 | 中国科学院声学研究所 | Device and method for active ultrasonic detection of fluid cavitation |
| CN203705398U (en) * | 2014-02-25 | 2014-07-09 | 三峡大学 | Water turbine abnormity early warning system based on ultrasonic detection |
| CN206159060U (en) * | 2016-10-20 | 2017-05-10 | 浙江理工大学 | Centrifugal pump cavitation monitoring devices |
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Patent Citations (6)
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| US5235524A (en) * | 1990-04-02 | 1993-08-10 | Rockwell International Corporation | Ultrasonic cavitation detection system |
| CN101435799A (en) * | 2008-12-19 | 2009-05-20 | 清华大学 | Failure diagnosis method and apparatus of hydroturbine based on acoustic emission technology |
| JP2010249637A (en) * | 2009-04-15 | 2010-11-04 | Yokogawa Electric Corp | Method for detecting state of fluid and state detecting device |
| CN102033106A (en) * | 2010-11-12 | 2011-04-27 | 中国科学院声学研究所 | Device and method for active ultrasonic detection of fluid cavitation |
| CN203705398U (en) * | 2014-02-25 | 2014-07-09 | 三峡大学 | Water turbine abnormity early warning system based on ultrasonic detection |
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| CN108895018A (en) * | 2018-04-20 | 2018-11-27 | 浙江理工大学 | A kind of device and method monitoring the development process of centrifugal blade cavitation |
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| CN106401989B (en) | 2017-11-14 |
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Application publication date: 20170215 Assignee: Yantai Longgang pump industry Limited by Share Ltd Assignor: Zhejiang Sci-Tech University Contract record no.: 2019330000013 Denomination of invention: Centrifugal pump cavitation monitoring device Granted publication date: 20171114 License type: Common License Record date: 20190128 |