Design And Experiment Of An Integrated Adjustable Constant Pressure Water Supply Device

Micro-irrigation is an important technical means of water-saving irrigation.The stability of inlet water pressure has an important impact on the performance of the irrigation and fertilization equipment or the automatic mixing device of water and fertilizer in the micro-irrigation system under different water pressures.Therefore,a set of constant pressure water supply system or device that can provide different water pressures is required.However,in the practical application process,the existing constant pressure water supply system,compared with the micro-irrigation system,still has problems such as low pressure stability accuracy.In order to solve the above problems,an integrated adjustable constant pressure water supply device is designed.The main research work and conclusions are as follows.(1)A vertical surround buffer pipe is designed.PVC pipe with a diameter of 25 mm is selected to design a pressure buffer tank with a height of 240 mm,a diameter of 210 mm and a shape of cylinder.The inlet and outlet are designed on the upper side and lower side of the buffer box respectively.(2)Part based on the design of the structure,design a kind of integration of adjustable constant pressure water supply device,the device of the main equipment includes: centrifugal pump pressure transmitter electromagnetic valve inverter and controller design power circuit,electromagnetic valve,drive circuit and so on working circuit and working principle of hardware circuit and software programming.(3)To realize voltage regulation process,according to the first pressure transmitter second 1 s testing cycle pressure transmitter output value and set the goal of constant pressure value,real-time computing export pressure of inlet water pressure and outlet water pressure difference and the target constant pressure value of error and error change rate,it is concluded that the current control which is suitable for the control rules,and enable the corresponding proportion-differential control algorithm to control centrifugal pump;Repeat the adjustment process until the error of constant pressure water supply stabilizes within the allowable range.(4)Analysis of test results shows that the device can be 0 ~ 0.4 MPa range of adjustable pressure,achieve the output pressure value stable and fast following the set pressure value,and the minimum scale value is 0.002 MPa pressure regulation,the maximum is 0.01 MPa,output pressure stability of the control error within 12%,the stable pressure response time is less than 60 s,satisfy the requirement of the practical application of the output pressure control.Finally,the safety of the device is tested,and the experimental results show that the device is reliable and not prone to failure.To sum up,through the vertical loop and buffer tank structure design,and based on the software and hardware design,on the basis of constant pressure water supply device,designed a integration by analyzing its whole machine test,to export the pressure value of the on-line continuous adjustable this device design is integrated portable structure,and equipped with castor wheels,small floor space,has the function of plug and play and movement can be different for fertigation equipment hydraulic performance tests with pressure adjustable constant working pressure,greatly improve the test efficiency.