A sleeve-type control valve mainly consists of a valve body, valve cover, sleeve, valve plug (valve disc), valve seat, and valve stem.
The sleeve and valve disc have a clearance fit. The sleeve has multiple throttling windows; the shape of these windows determines the flow characteristics of the control valve, and the size of the window area affects the flow coefficient. The valve seat uses a self-centering, threadless snap-fit structure, pressed tightly onto the valve body by the upper valve cover. The valve disc has symmetrically distributed balance holes parallel to the axial direction, connecting the chambers on the upper and lower end faces of the valve disc to reduce the unbalanced force exerted by the medium on the valve disc. The sleeve has a polytetrafluoroethylene (PTFE) balance sealing seat, which mates with the sealing surface on the valve disc to form a shut-off sealing pair. The sleeve provides two basic types of throttling windows:Large windows and small orifices (jet type).