Research on Automatically Cleaning Silt device for flow Measuring Equipment in Branch of Irrigation Area
The average annual rainfall in northwest China is less than 400 mm,which belongs to the perennial irrigation area.Without irriga-tion,there will be no stable yield.Among them,the mud and sand content of the Yellow River introduced from the Yellow River diversion ir-rigation area is relatively high,and sediment accumulation will be formed in the channels with low flow velocity in branch and lateral canals.When the sediment accumulates to a certain extent in the flow measuring equipment and gate measurement and control system of the chan-nel,it will seriously affect the accuracy of flow measurement and the perception of gate opening.In order to solve the problem of effective ap-plication of water flow measuring equipment with high sediment content in smart irrigation areas and improve the accurate measurement of small canal flow,an ultrasonic vibration unit was designed,which can be placed in the flow measuring equipment and integrated gate of mea-surement and control.The vibration unit comprises a sealing box,a metal cover plate and a circuit board.The sealing box is provided with a top opening,and the metal cover plate is on the top opening of the sealing box.The circuit board is provided with a signal interface circuit,a power module,a delay circuit,a PWM(Pulse Width Modulation)control chip,a MOS transistor circuit,a leakage protection chip,a trans-former circuit,a matching circuit and an ultrasonic transducer.The working time and working interval of the vibration unit are controlled by the delay chip,which can be configured by the signal of the control interface.The opening and closing of the MOSFET transistor is controlled by the PWM control chip,and the ultrasonic frequency is controlled by the PWM frequency.The control of the vibration unit is integrated in the flow measurement system,and the system gives control instructions according to the field situation,which can be divided into fixed and dynamic modes.The device can automatically turn on the vibration to remove the accumulated sediment according to the situation of sediment accumulation.Our prototype was tested in the laboratory and got a set of results of vibration sand removal under different degrees of accumula-tion,which verified the effective vibration time for removing the accumulated sediment,and was examined on site in Ningxia.The experimen-tal results show that the duration of ultrasonic vibration will increase with the increase of the amount of sediment accumulation.When the thickness of sediment is less than 30 mm,the ultrasonic vibration device can effectively remove the sediment after starting the vibration de-vice once(3 min).
flow measuring equipmentautomatically cleaning accumulated sedimentsmart irrigated areaultrasonic vibration unit
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