Where turbine conditions are more severe, and gas temperatures are higher, the articulated mirror system is offered. This system is designed to minimise both the length of the pyrometer probe which is inserted in to the gas stream and also the duration of the insertion tume.
A pyrometer probe, which contains a moveable mirror, is mounted in a pneumatic actuator. The sight tube diameter is larger than the fixed mirror to accomodate the mirror movement mechanism. The pneumatic system inserts the pyrometer probe a small distance into the gas stream and the scan range is determined by the limits on the mirror positioning system. The mirror is connected to a fixed point in the sight tube tip and also to a slot in a push rod and the push rod moves up and down within the sight tube to vary the viewing angle. The tip is inserted a short distance into a fixed point in the gas stream and data is then collected continuously as the mirror is driven through it's range of movement.