圆形喷灌机注肥泵的设计与试验研究

圆形喷灌机的喷灌施肥一体化作业是国内外精准农业的研究热点,选用工作压力高、流量小且稳定的施肥装置是确保高均匀性喷灌施肥的技术关键.针对圆形喷灌机实际应用和作物施肥特点,设计了一台双缸柱塞式注肥泵,包括液力端、传动端、柱塞、密封及配套动力等,单缸设计流量为150 L/h,最大工作压力为1.0 MPa;对试制样机进行了历时100 h的耐久性试验、20%~100%行程范围的调节试验和30~50 Hz频率范围的变频调节试验.结果表明：研发的柱塞式注肥泵流量随着出口压力的增大而有所减少,但不同出口压力下,流量在100 h内的变异系数均小于5%;改变柱塞行程,泵的实际流量和理论流量几乎一致,两者间的最大差值在行程百分比为60%处,为理论流量值的7.5%;泵的流量随着电源频率的增大呈线性上升关系.试验还表明,改变柱塞行程和电源频率可以调节注肥泵的注肥流量,扩大注肥泵的流量范围.开发的注肥泵适用于圆形喷灌机等灌溉施肥系统,可实现施肥的精准控制.

Design and experiment on fertigation plunger pump in center pivot irrigation system

Fertigation technology for center pivot irrigation systems has increasingly become a research focus in precision agriculture inside and outside China. Fertigation equipment with high working pressure and low but stable flow rate is the key factor to guarantee high fertigation uniformity. In order to meet the requirement of center pivot irrigation systems a doublecylinder plunger pump including liquid ends, drive ends, pistons, seals, AC motor and so on was designed by teristics into account. The design flow rate per cylinder is 150 L/h and taking crop fertilization characthe maximum working pressure is 1.0 MPa. Meanwhile 100 h durability test, stroke regulation test （20% -100% stroke） and frequency conversion test （30 -50 Hz） on a prototype of the pump were conducted. It was showed that the discharge of the pump decreases with increasing discharge pressure and all the variation coefficients of discharge within I00 h are smaller than 5% under various discharge pressures. The measured discharge is almost the same as the theoretical one, and the maximum error between them is just 7.5% at a 60% stroke. Additionally, the pump discharge rises linearly with AC motor frequency. Clearly, the pump discharge can be adjusted by changing the plunger stroke and altering the AC motor frequency toexpand the range of pump discharge. The developed plunger pump is applicable for a fertigation system, such as the center pivot irrigation system to realize precision fertilization.