US Patent 7373950 Ceramic control valve

A ceramic control valve includes a valve casing, and a control device including a linking seat and a control lever. The drive block of the control lever has a spherical surface. The receiving hole of the linking seat has a wall having a first portion in contact with the spherical surface of the drive block and a second portion spaced from the spherical surface of the drive block, thereby forming a plurality of gaps. Thus, the gaps located between the drive block and the receiving hole keep a smooth circulation of the air flow, thereby preventing the drive block from being jammed in the receiving hole due to deformation of heat expansion, so that the control lever is operated normally.