The Research On Open Channel Flowmeter Calibration Specification For Online

As a flow measuring instrument， open channel flow meter was widely used in urbanwater supply aqueducts, thermal power plant cooling water diversion and drainage, sewagetreatment inflow and outfall, industrial and mining wastewater discharge and waterconservancy and agricultural irrigation channels and other fields, the accuracy of themeasurement is directly related to people’s livelihood. At present, the test of open channelflow meter only carried out in the laboratory, and maneuverability in laboratory is not good;there is no a reliable basis in current on-site open channel flow meter calibration, even we tryour best to conduct on-site calibration, the main work was to get the relevant physicalparameters on the characteristics of the impact of open channel flow meter, such as theparameters of the open channel weir tank size, water level converter, calculated theuncertainty of each component, and then synthesize them. This method does not consider theimpact of installation, and underestimated the impact of the making of the weir trough, it wasnot suitable to carry out the test for its complex. Therefore, it is necessary to study the fieldopen channel flowmeter calibration method, and format a common field calibrationspecifications, make the on-site calibration evidence-based, which can both improve theefficiency of online measurement and the calibration, and ensure the accuracy andeffectiveness of measurement activities.This paper put forward and discussed the on-line calibration of open channel flow meter,It can avoid the disadvantage above and make the on-line calibration possible. With thecalibration was put forward and improved, it makes the staff calibrate the open channel fastthan before and also can make the parameter appropriate.We carry out the experiment by using a group of high-precision current meters, designdifferent stationing methods, get the current flowing speed in the selected points in the openchannel flow meter, then get the flow values by using speed-area method. interpolationmethod was introduced to get the instant value by cumulating all the micro flow values. Atlast, we calculate the error by comparing our system and the standard-electromagnetic flow meter to assess actual precision, and find out the relation between interpolation andtruth-value. This paper concluded how to apply the interpolation-method into the calibrationof open channel flow meter, and gave out basis for on-line calibration specification.