[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fsDD3e-76HRCpBCXlxmZGc7JP8lv1-FvTRkd1fjVc7Xs":3},{"answer":4,"createTime":5,"id":6,"options":7,"origin":12,"question":19,"related":20,"source":30,"type":31},[],"2023-12-18 23:45:28",115812897,[8,9,10,11],"closed","opened fully","cracked open","partly open",{"count":13,"courseId":14,"courseImg":15,"courseName":16,"workId":17,"workName":18},10,"387be972678c6b7c964b909f59deaab6","https:\u002F\u002Ftihai-oss-cloud.itihey.com\u002Fimg\u002Fb352afbc1ea29fbb6d8c348e7b56bb46.jpg","轮机英语","42393c376deb419398ae28899790f518","船用泵4","When starting a centrifugal pump, the discharge valve should be ____",[21,32,41,50,57,66,75,83,92,95],{"answer":22,"createTime":5,"id":23,"options":24,"question":29,"source":30,"type":31},[],115812880,[25,26,27,28],"cavitation","water hammer","fluid friction","steam knock","Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump is a result of____","v1",0,{"answer":33,"createTime":5,"id":34,"options":35,"question":40,"source":30,"type":31},[],115812882,[36,37,38,39],"valves in the system being shut","suction strainers blocked","either A or B","neither A nor B","Common faults with centrifugal pumps, such as no discharge, may be a result of _______",{"answer":42,"createTime":5,"id":43,"options":44,"question":49,"source":30,"type":31},[],115812884,[45,46,47,48],"Close radial clearance between impeller hub and casing","Low rotational speed of impeller","Removable end plate","Replaceable impeller and casing wear rings","Which feature of a centrifugal pump reduces the need for renewing worn impellers and pump casings",{"answer":51,"createTime":5,"id":52,"options":53,"question":56,"source":30,"type":31},[],115812887,[54,55,38,39],"the mechanical seal","packed stuffing boxes","Shaft sealing in a centrifugal pump can be affected by _____",{"answer":58,"createTime":5,"id":59,"options":60,"question":65,"source":30,"type":31},[],115812888,[61,62,63,64],"non-pulsating","pulsating","positive","non-positive","Centrifugal pumps are popular because they are very simple in construction, and produce smooth, constant, _____ discharge",{"answer":67,"createTime":5,"id":68,"options":69,"question":74,"source":30,"type":31},[],115812890,[70,71,72,73],"motor controller overload would open","pump would eventually overheat","relief valve would continuously cycle open","motor would overheat","If a centrifugal pump were continually operated with the discharge valve closed, the _____",{"answer":76,"createTime":5,"id":77,"options":78,"question":82,"source":30,"type":31},[],115812892,[25,79,80,81],"electrolysis","abrasion","friction","Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by _____",{"answer":84,"createTime":5,"id":85,"options":86,"question":91,"source":30,"type":31},[],115812894,[87,88,89,90],"noise and vibration","an increase in discharge pressure","an increase in suction pressure","lifting of the relief valve","The usual symptoms of cavitation in a centrifugal pump is _____",{"answer":93,"createTime":5,"id":6,"options":94,"question":19,"source":30,"type":31},[],[8,9,10,11],{"answer":96,"createTime":5,"id":97,"options":98,"question":103,"source":30,"type":31},[],115812901,[99,100,101,102],"shaft and impeller","motor and pump shaft","casing and impeller wearing rings","lantern ring and impeller","To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the _____"]