③对于具有上、下调节圈（导向套和阀座上各有一个调节圈）的结构，其调整要复杂一些。阀座调节圈用来改变阀瓣与调节圈之间通道的大小，从而改变阀门初始开启时压力在阀瓣与调节圈之间腔室内积聚程度的大小。当升高阀座调节圈时，压力积聚的程度增大，从而使阀门比例开启的阶段减小而较快地达到突然的急速开启。R900444069DBE10-3X/315XYG24Z4VR900350629DBE10-3X/315XYZ4-246R900387032DBE10-3X/315YEXR900400149DBE10-3X/315YG12FHR900336877DBE10-3X/315YG24JR900958418DBE10-3X/315YG24K4R900337424DBE10-3X/315YG24NZ4R900442322DBE10-3X/315YG24Z4R900385136DBE10-3X/315YG24Z4MKR900475194DBE10-3X/315YG24Z4VR900466235DBE10-3X/50XYG24Z4R900396045DBE10-3X/50YG12Z4VR900520284DBE10-3X/50YG24EXR900587338DBE10-3X/50YG24JR900403979DBE10-3X/50YG24NZ4R900447597DBE10-3X/50YG24Z4R900481495DBE10-3X/50YG24Z4MKR900455119DBE10-3X/50YG24Z4VR900576604DBE10-3X=200YG24Z4-308R900573783DBE10-5X/100XYG24Z4M)