Gate arrangement

The gate arrangement is provided in order to regulate coolant airflow in a path typically in a turbine blade of a jet engine. The gate arrangement includes a gate component having an opening end which at low temperature is closed by a gate member . Due to different coefficients of expansion between the gate component and the gate member when the arrangement increases in temperature there is a divergence between a seal end of the gate member in order to open the opening end of the gate component and to allow coolant airflow through the arrangement . Thus, coolant airflow is allowed for high temperatures but as the gate component and gate member converge at sustained typically lower temperatures coolant airflow is stopped in order to prevent unnecessary cooling and so provide greater thermal efficiency.