CN101178322A - Concrete pump real time flow measurement method and system - Google Patents
Concrete pump real time flow measurement method and system Download PDFInfo
- Publication number
- CN101178322A CN101178322A CNA2007101644129A CN200710164412A CN101178322A CN 101178322 A CN101178322 A CN 101178322A CN A2007101644129 A CNA2007101644129 A CN A2007101644129A CN 200710164412 A CN200710164412 A CN 200710164412A CN 101178322 A CN101178322 A CN 101178322A
- Authority
- CN
- China
- Prior art keywords
- concrete
- module
- wedge
- conveying pipe
- ultrasound wave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Measuring Volume Flow (AREA)
Abstract
The invention discloses a measuring method and system of concrete pump real time flux. Four acoustic wedges provided with an ultrasonic sensor are respectively arranged on a concrete transfer piping; wherein, two ultrasonic emission sensors launch ultrasonic with certain intensity to the concrete flowing in the concrete transfer piping through a launching module. The ultrasonic after passing through the concrete is modulated by a flowing noise signal in the concrete. A receiving module detects the flowing noise signal by two ultrasonic receiving sensors, carries through signal processing to extract useful flowing noise containing concrete flowing information, measures the time interval of the concrete for passing through two sections with a certain distance and calculates the flowing speed of the concrete. As the section surface of the concrete transfer piping is a fixed value, the concrete pump real time flux can be measured according to the measured concrete velocity of flow. When measuring, the flow field distribution of the concrete in the concrete transfer piping is not influenced and the measuring accuracy is almost not influenced by parameters like temperature, pressure and concentration, etc. of the concrete.
Description
Technical field
The present invention relates to the method and system of flow measurement, especially relate to a kind of concrete pump real time flow measurement method and system.
Background technology
Concrete stirring and pumping are normally carried out in the two places of apart from each other, and stirring, transportation and construction party be Chang Weisan different unit also.A side who is in a disadvantageous position because of information asymmetry in the architecture machinery rental industry---construction user side---proposes to be badly in need of the deficiency that flow measuring system (mainly being the flow measuring system with pump truck) remedies this respect.In the demand that also exists aspect the evaluation of pump (car) monitoring running state, construction management and construction quality, pump truck quality flow measuring system.Concrete flow measurement technology has become one in construction implement engineering practical application technical matters that needs to be resolved hurrily, with the exploitation of the flow measurement device of car and control system, statistic management system, be considered as the significant function of pump truck of new generation by domestic each main building machinery manufacturing enterprise.
The direct research of relevant concrete pump flow metering technology both at home and abroad rarely has report, just using or studying among metering method and technical scheme comprise:
(1) method of utilizing displacement transducer, switch sensor to carry out flow metering.This method adopts switch sensor that the pump stroke number of times is counted, and carries out the metering of piston concrete pump (steam piano) flow according to the pumping efficiency of setting according to experience.Owing to can not get rid of the influence that " idle motion " and top hole pressure change on metering method, there is big error in dipping in this method.
(2) utilize the hydraulic system signal to carry out the method for flow metering.This method utilizes the reciprocal corresponding relation of the pressure signal of hydraulic system and piston cylinder to carry out the flow metering of concrete pump.Though this method has simple and reliable characteristics, still rest in essence on the reciprocal time of measuring hydraulic drive piston, and can not distinguish back pressure signal, the precision under complex working condition is very limited.
(3) based on surveying the metering method that sucks volumetric efficiency.Suck volumetric efficiency by the field measurement concrete cylinder and calculate the average volumetric efficiency that sucks, and measure the number of stroke of piston per minute when range of concrete cylinder, according to the average volumetric efficiency that sucks the concrete pump flow is measured then.This method principle is simple, can reduce the error of the actual mean flow rate that causes because of coefficient of flow is inaccurate.But require to have special measuring channel, also increased operating personnel's labor capacity simultaneously.Not only expend time in, frequent mensuration is also unrealistic.
Summary of the invention
The object of the present invention is to provide a kind of concrete pump real time flow measurement method and system.The actual pump discharge of concrete pump can calculate in this system.
The technical solution used in the present invention is as follows:
One. concrete pump real time flow measurement method:
The present invention is installed in four sound wedges on the concrete conveying pipe respectively, four ultrasonic sensors are installed in respectively in four sound wedges, wherein two ultrasonic emitting sensors are launched the ultrasound wave of certain intensity by the concrete that transmitter module flows in concrete conveying pipe, ultrasound wave is modulated by the flowing noise signal in the concrete through behind the concrete, receiver module detects flowing noise signal and carries out signal Processing by two ultrasound wave receiving sensors, extract the useful hydrodynamic noise that contains the mobile information of concrete, measure concrete and pass through the time interval in two cross sections of certain distance apart, calculate concrete flowing velocity, because the sectional area of concrete conveying pipe is a definite value, just can measure concrete pump real time flow according to the concrete flow velocity that records; The concrete steps of this method are as follows:
1) four sound wedges is installed in respectively on the concrete conveying pipe, four ultrasonic sensors are installed in respectively in four sound wedges;
2) transmitter module is connected with two ultrasonic emitting sensors respectively, makes two ultrasonic emitting sensors be in emission state always;
3) receiver module is connected with two ultrasound wave receiving sensors respectively, receives the signal of two ultrasound wave receiving sensor outputs always;
4) high frequency oscillation module is connected with DSP, produces emission ultrasound wave trigger pulse;
5) signal processing module is connected with receiver module, the detected flowing noise signal of receiver module is handled;
6) calculate concrete and pass through to obtain concrete flowing velocity,, just can measure concrete pump real time flow according to the concrete flow velocity that records because the sectional area of concrete conveying pipe is a definite value at a distance of the time interval in two cross sections of certain distance;
In the formula:
Actual flow (the m that the Q-concrete pump is total
3); Sectional area (the m of S-concrete conveying pipe
2); υ-concrete flow velocity (m/s); Two ultrasonic emitting of L-(reception) sensor installation intervals (m); τ
0-concrete passes through the time interval (s) at a distance of two cross sections of certain distance.
Two. the concrete pump real time flow measuring system:
Comprise concrete pump; Also comprise two ultrasonic emitting sensors, two ultrasound wave receiving sensors, four sound wedges, concrete conveying pipe, signal processing module, transmitter module, receiver module, temperature compensation module, the flow display module, DSP, serial communication module and high frequency oscillation module; First wedge and the 3rd wedge place the concrete conveying pipe both sides respectively, axial along concrete conveying pipe again, second sound wedge and fourth sound wedge place the concrete conveying pipe both sides respectively, the first ultrasonic emitting sensor is installed in first wedge, the second ultrasonic emitting sensor is installed in the second sound wedge, the first ultrasound wave receiving sensor is installed in the 3rd wedge, and the second ultrasound wave receiving sensor is installed in the fourth sound wedge; Transmitter module is connected with first, second ultrasonic emitting sensor respectively, and receiver module is connected with first, second ultrasound wave receiving sensor respectively; Signal processing module and receiver module, DSP respectively with signal processing module, temperature compensation module, the flow display module, serial communication module is connected with high frequency oscillation module.
Described first wedge and the 3rd wedge, second sound wedge and fourth sound wedge are all parallel tilting respectively or vertically place the concrete conveying pipe both sides.
The beneficial effect that the present invention has is:
By detecting the ultrasound wave of being modulated by flowing noise signal in the concrete conveying pipe, extract the useful hydrodynamic noise that contains the mobile information of concrete, measure concrete and pass through the time interval in two cross sections of certain distance apart, calculate concrete flowing velocity, concrete pump real time flow is measured.Do not influence concrete Flow Field Distribution in the concrete conveying pipe during measurement, and accuracy of measurement is subjected to concrete temperature, pressure hardly, concentration is isoparametric influences.
Description of drawings
Fig. 1 is a general structure principle schematic of the present invention.
Fig. 2 is a hardware configuration principle schematic of the present invention.
Fig. 3 is a software configuration principle schematic of the present invention.
Fig. 4 is a workflow principle schematic of the present invention.
Among the figure: 1, ultrasonic emitting sensor, 2, the ultrasonic emitting sensor, 3, the ultrasound wave receiving sensor, 4, ultrasound wave receiving sensor, 5, sound wedge, 6, sound wedge, 7, sound wedge, 8, the sound wedge, 9, concrete conveying pipe, 10, signal processing module, 11, transmitter module 12, receiver module, 13, temperature compensation module, 14, flow display module, 15, DSP, 16, serial communication module, 17, high frequency oscillation module, 18, concrete pump.
Embodiment
As shown in Figure 1 and Figure 2, the present invention includes concrete pump; Also comprise two ultrasonic emitting sensors 1,2, two ultrasound wave receiving sensors 3,4, four sound wedges 5,6,7,8, concrete conveying pipe 9, signal processing module 10, transmitter module 11, receiver module 12, temperature compensation module 13, flow display module 14, DSP15, serial communication module 16 and high frequency oscillation module 17; First wedge 5 and the 3rd wedge 7 minutes
Do not place concrete conveying pipe 9 both sides, axial along concrete conveying pipe 9 again, second sound wedge 6 and fourth sound wedge 8 place concrete conveying pipe 9 both sides respectively, the first ultrasonic emitting sensor 1 is installed in first wedge 5, the second ultrasonic emitting sensor 2 is installed in the second sound wedge 6, the first ultrasound wave receiving sensor 3 is installed in the 3rd wedge 7, and the second ultrasound wave receiving sensor 4 is installed in the fourth sound wedge 8; Transmitter module 11 is connected with first, second ultrasonic emitting sensor 1,2 respectively, and receiver module 12 is connected with first, second ultrasound wave receiving sensor 3,4 respectively; Signal processing module 10 and receiver module 12, DSP15 respectively with signal processing module 10, temperature compensation module 13, flow display module 14, serial communication module 16 is connected with high frequency oscillation module 17.
Described first wedge 5 and the 3rd wedge 7, second sound wedge 6 and fourth sound wedge 8 are all parallel tilting respectively or vertically place concrete conveying pipe 9 both sides.
As shown in Figure 3, software systems of the present invention comprise self check and fault processing module, parameter setting and modified module, measurement and signal processing module, control and serial communication module and data presentation and print module.
The course of work of the present invention is as follows:
In conjunction with Fig. 2 and Fig. 4, start measuring system, system at first carries out self check, carries out the setting of various measurement parameters then.The DSP program is sent and is controlled signal to high frequency oscillation module, produces emission ultrasound wave trigger pulse, and ultrasonic transducer begins to launch ultrasound wave.After receiver module receives modulation signal, modulation signal is carried out filtering, amplification and demodulation, isolate the low frequency flow signals that contains rate of flow of fluid information, be delivered to A/D converter and carry out data acquisition, signal is transferred to DSP.The cross correlation function that establishment DSP program is calculated flowing noise signal carries out error correction and data processing according to the various measurement parameters of gathering in real time simultaneously, calculates real time discharge volume and integrated flux, and result of calculation is shown.
As shown in Figure 2, ultrasonic emitting sensor 1,2 is launched the ultrasound wave of certain intensity by the concrete of transmitter module 11 in concrete conveying pipe 9, ultrasound wave is modulated by the flowing noise signal in the concrete through behind the concrete, arrive ultrasound wave receiving sensor 3,4, be received module 12 then and receive.By the appropriate signals demodulation, from ultrasound wave receiving sensor 3,4, extract respectively and mobile relevant flowing noise signal x (t) and the y (t) of situation of concrete.When concrete in pipeline during smooth flow, flowing noise signal x (t) and y (t) can regard as respectively from ergodic stationary stochastic process { x at random
iAnd { y (t) }
i(t) } a sample function.X (t) and y (t) are done computing cross-correlation can obtain cross correlation function R
Xy(τ) be:
When the distance between the ultrasonic emitting sensor 1,2 within the specific limits the time, fluid flowing noise signal x (t) and y (t) have certain similarity, its cross correlation function R
Xy(τ) peak value, the pairing time shifting τ of this peak value can appear
0Be the time of concrete from ultrasonic emitting sensor 1 to ultrasonic emitting sensor 2 under the perfect condition.In this measuring system, if the distance between ultrasonic emitting sensor 1 and the ultrasonic emitting sensor 2 is enough little, and the straight length of ultrasonic emitting sensor 1 and ultrasonic emitting sensor 2 front and back is long, so when fluid when ultrasonic emitting sensor 1 flow to ultrasonic emitting sensor 2, the moving phase of fluid is less to changing, can be similar to and think that this flow system satisfies " solidifying " flow model assumed condition, so the speed υ of fluid is:
Because the sectional area S of concrete conveying pipe is a definite value, just can obtain concrete flow according to the flow velocity υ that records:
Device such as ultrasonic emitting sensor T/R40, ultrasound wave receiving sensor T/R40, transmitter module RBA-24, receiver module RBA-23, serial communication module ADAM-4510I, high frequency oscillation module FU-19, temperature compensation module 143-131A, signal processing module KLM-4701, flow display module LCM141 and DSP that the present invention adopts all can buy on the market.
Claims (3)
1. concrete pump real time flow measurement method, it is characterized in that: be installed in four sound wedges on the concrete conveying pipe respectively, four ultrasonic sensors are installed in respectively in four sound wedges, wherein two ultrasonic emitting sensors are launched the ultrasound wave of certain intensity by the concrete that transmitter module flows in concrete conveying pipe, ultrasound wave is modulated by the flowing noise signal in the concrete through behind the concrete, receiver module detects flowing noise signal and carries out signal Processing by two ultrasound wave receiving sensors, extract the useful hydrodynamic noise that contains the mobile information of concrete, measure concrete and pass through the time interval in two cross sections of certain distance apart, calculate concrete flowing velocity, because the sectional area of concrete conveying pipe is a definite value, just can measure concrete pump real time flow according to the concrete flow velocity that records; The concrete steps of this method are as follows:
1) four sound wedges is installed in respectively on the concrete conveying pipe, four ultrasonic sensors are installed in respectively in four sound wedges;
2) transmitter module is connected with two ultrasonic emitting sensors respectively, makes two ultrasonic emitting sensors be in emission state always;
3) receiver module is connected with two ultrasound wave receiving sensors respectively, receives the signal of two ultrasound wave receiving sensor outputs always;
4) high frequency oscillation module is connected with DSP, produces emission ultrasound wave trigger pulse;
5) signal processing module is connected with receiver module, the detected flowing noise signal of receiver module is handled;
6) calculate concrete and pass through to obtain concrete flowing velocity,, just can measure concrete pump real time flow according to the concrete flow velocity that records because the sectional area of concrete conveying pipe is a definite value at a distance of the time interval in two cross sections of certain distance;
In the formula:
Actual flow (the m that the Q-concrete pump is total
3); Sectional area (the m of S-concrete conveying pipe
2); υ-concrete flow velocity (m/s); Two ultrasonic emitting of L-(reception) sensor installation intervals (m); τ
0-concrete passes through the time interval (s) at a distance of two cross sections of certain distance.
2. a concrete pump real time flow measuring system comprises concrete pump (18); It is characterized in that: also comprise two ultrasonic emitting sensors (1,2), two ultrasound wave receiving sensors (3,4), four sound wedges (5,6,7,8), concrete conveying pipe (9), signal processing module (10), transmitter module (11), receiver module (12), temperature compensation module (13), flow display module (14), DSP (15), serial communication module (16) and high frequency oscillation module (17); First wedge (5) and the 3rd wedge (7) place concrete conveying pipe (9) both sides respectively, axial along concrete conveying pipe (9) again, second sound wedge (6) and fourth sound wedge (8) place concrete conveying pipe (9) both sides respectively, the first ultrasonic emitting sensor (1) is installed in first wedge (5), the second ultrasonic emitting sensor (2) is installed in the second sound wedge (6), the first ultrasound wave receiving sensor (3) is installed in the 3rd wedge (7), and the second ultrasound wave receiving sensor (4) is installed in the fourth sound wedge (8); Transmitter module (11) is connected with first, second ultrasonic emitting sensor (1,2) respectively, and receiver module (12) is connected with first, second ultrasound wave receiving sensor (3,4) respectively; Signal processing module (10) and receiver module (12), DSP (15) respectively with signal processing module (10), temperature compensation module (13), flow display module (14), serial communication module (16) is connected with high frequency oscillation module (17).
3. a kind of concrete pump real time flow measuring system according to claim 2 is characterized in that: described first wedge (5) and the 3rd wedge (7), second sound wedge (6) and fourth sound wedge (8) are all parallel tilting respectively or vertically place concrete conveying pipe (9) both sides.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CNB2007101644129A CN100570284C (en) | 2007-11-29 | 2007-11-29 | Concrete pump real time flow measurement method and system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CNB2007101644129A CN100570284C (en) | 2007-11-29 | 2007-11-29 | Concrete pump real time flow measurement method and system |
Publications (2)
Publication Number | Publication Date |
---|---|
CN101178322A true CN101178322A (en) | 2008-05-14 |
CN100570284C CN100570284C (en) | 2009-12-16 |
Family
ID=39404663
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CNB2007101644129A Expired - Fee Related CN100570284C (en) | 2007-11-29 | 2007-11-29 | Concrete pump real time flow measurement method and system |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN100570284C (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102478416A (en) * | 2010-11-30 | 2012-05-30 | 航天长征化学工程股份有限公司 | Gas-solid mixed phase flow flowmeter and flow measuring method |
CN102749386A (en) * | 2011-04-19 | 2012-10-24 | 香港科技大学 | System and method for in-situ hydration monitoring and damage detection of concrete structure and sensors used by system and method |
CN103454013A (en) * | 2013-09-12 | 2013-12-18 | 重庆大学 | Three-dimensional temperature field acoustic detection device and method in microwave heating environment |
CN104641118A (en) * | 2012-07-11 | 2015-05-20 | 威乐欧洲股份公司 | Centrifugal pump with ultrasound flow-through measurement device |
CN104797909A (en) * | 2012-11-21 | 2015-07-22 | 贝卡尔特公司 | A method to determine or monitor the amount or the distribution of additional material present in a flow of a flowable substance |
WO2017148846A1 (en) * | 2016-03-02 | 2017-09-08 | Bestsens Ag | Gear pump and method for monitoring a gear pump |
CN109211338A (en) * | 2017-06-29 | 2019-01-15 | 代傲表计有限公司 | For determining the method and measuring device of Fluid Volume |
CN111946606A (en) * | 2020-06-28 | 2020-11-17 | 广州海达安控智能科技有限公司 | CFG pile concrete pump discharge capacity calculation method, electronic equipment and storage medium |
CN112460040A (en) * | 2020-11-23 | 2021-03-09 | 中国华能集团清洁能源技术研究院有限公司 | Pump sound wave monitoring system and method |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1289916A (en) * | 1999-09-29 | 2001-04-04 | 王智慧 | Ultrasonic cross-correlation method for measuring flow of crude oil underground |
-
2007
- 2007-11-29 CN CNB2007101644129A patent/CN100570284C/en not_active Expired - Fee Related
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102478416A (en) * | 2010-11-30 | 2012-05-30 | 航天长征化学工程股份有限公司 | Gas-solid mixed phase flow flowmeter and flow measuring method |
CN102478416B (en) * | 2010-11-30 | 2016-08-17 | 航天长征化学工程股份有限公司 | Gas-solid mixed phase flow flowmeter and flow measuring method |
CN102749386A (en) * | 2011-04-19 | 2012-10-24 | 香港科技大学 | System and method for in-situ hydration monitoring and damage detection of concrete structure and sensors used by system and method |
CN104641118A (en) * | 2012-07-11 | 2015-05-20 | 威乐欧洲股份公司 | Centrifugal pump with ultrasound flow-through measurement device |
CN104641118B (en) * | 2012-07-11 | 2017-11-24 | 威乐欧洲股份公司 | Drum pump including flowmeter |
CN104797909A (en) * | 2012-11-21 | 2015-07-22 | 贝卡尔特公司 | A method to determine or monitor the amount or the distribution of additional material present in a flow of a flowable substance |
CN103454013B (en) * | 2013-09-12 | 2016-04-06 | 重庆大学 | Three-dimensional temperature field acoustic detection device under microwave heating environment and method |
CN103454013A (en) * | 2013-09-12 | 2013-12-18 | 重庆大学 | Three-dimensional temperature field acoustic detection device and method in microwave heating environment |
WO2017148846A1 (en) * | 2016-03-02 | 2017-09-08 | Bestsens Ag | Gear pump and method for monitoring a gear pump |
CN108700060A (en) * | 2016-03-02 | 2018-10-23 | 贝斯特森斯有限公司 | Gear pump and method for monitoring gear pump |
CN109211338A (en) * | 2017-06-29 | 2019-01-15 | 代傲表计有限公司 | For determining the method and measuring device of Fluid Volume |
CN109211338B (en) * | 2017-06-29 | 2021-12-21 | 代傲表计有限公司 | Method and measuring device for determining a fluid quantity |
CN111946606A (en) * | 2020-06-28 | 2020-11-17 | 广州海达安控智能科技有限公司 | CFG pile concrete pump discharge capacity calculation method, electronic equipment and storage medium |
CN111946606B (en) * | 2020-06-28 | 2023-04-07 | 广州市中海达测绘仪器有限公司 | CFG pile concrete pump discharge capacity calculation method, electronic equipment and storage medium |
CN112460040A (en) * | 2020-11-23 | 2021-03-09 | 中国华能集团清洁能源技术研究院有限公司 | Pump sound wave monitoring system and method |
Also Published As
Publication number | Publication date |
---|---|
CN100570284C (en) | 2009-12-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN100570284C (en) | Concrete pump real time flow measurement method and system | |
CN100406733C (en) | Metering method and system for real time discharge volume of piston type concrete pump | |
CN203147291U (en) | System capable of monitoring pipeline leakage by means of infrasonic waves, flow balance and negative pressure waves | |
CN101968162B (en) | Pipeline leakage positioning system and method based on collaborative detection with negative pressure wave and sound wave | |
CN101464171B (en) | Ultrasonic flux detection method | |
CN101004353A (en) | Detection method of time difference cross in use for ultrasonic flowmeter | |
CA2619008A1 (en) | Methods for determining transducer delay time and transducer separation in ultrasonic flow meters | |
CN106090629A (en) | Urban Underground piping lane water supply line leak detection system and method | |
US10364816B2 (en) | Remote pump managing device | |
US10775214B2 (en) | Insertion type ultrasonic flow meter, flow measuring system and method | |
CN104634424B (en) | For the condition detection method of ultrasonic flowmeter | |
CN104011530A (en) | Method and device for detecting and analyzing deposits | |
CN102519542A (en) | Pressure liquid level sensor | |
CN100465589C (en) | Concrete pump real time flow measurement method and apparatus | |
CN104295907A (en) | System and method for detecting blockage position of pipeline | |
CN100573057C (en) | Piston type concrete pump real time flow measurement method and device | |
CN202770498U (en) | Ultrasonic level gauge | |
CN202677205U (en) | Ultrasound metering and flow control system | |
CN203069223U (en) | Synchronous phase code time difference detection device for ultrasonic flowmeter | |
CN202580643U (en) | Safety online management system for pipelines | |
CN100383510C (en) | Detection of oil and gas pipeline leakage by additional dynamic micro-pressure signal | |
CN206291930U (en) | A kind of ultrasonic wave mass flowmenter | |
CN109681787A (en) | A kind of pipeline leakage positioning system and method | |
CN1289916A (en) | Ultrasonic cross-correlation method for measuring flow of crude oil underground | |
CN104296814A (en) | Flow measuring device for sewage containing solid garbage |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
C17 | Cessation of patent right | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091216 Termination date: 20101129 |