SYSTEM TO ADJUST BLADE HEAD CLEARANCE IN GAS-TURBINE ENGINE Russian patent published in 2003 - IPC

FIELD: mechanical engineering; gas-turbine engines. SUBSTANCE: ring case in formed on engine housing to which circular row of segments of protective casing is secured getting close to blade heads. Ring case forms passage for air communicating with housing to deliver cooling air to housing. Temperature-controlled passive ring valve is formed by two overlapping metal ring segments featuring different thermal expansion coefficients selected to provide radial clearance between ring segments when valve temperature reaches preset value. Radial clearance provides passage of cooling air into casing to cool housing with fitted-on circular row of segments of protective casing to adjust increase of radial dimension and preclude contact of turbine blades with housing. EFFECT: enhanced reliability in operation. 9 cl, 7 dwg