Abstract: A sector gear split into sections for secure engagement around a tripper shaft, allowing the gear to be replaced in less time, by a smaller crew, and with fewer tools.

Abstract: A temperature measuring system is described which is activated in response to the occurrence of detecting a temperature greater than a predefined critical temperature which includes a transceiver which receives an incoming electromagnetic wave, a temperature sensing means, e.g. a gas thermometer to measure the temperature of the desired component, and an electromagnetically interrogatable transponder chip capable of selectively transitioning from an inactive state to an active state upon the temperature exceeding the predefined critical temperature. The transponder chip when in the active state, converts the electromagnetic wave to a surface acoustic wave which passes over the transponder chip and upon exiting from the transponder chip is reconverted to an electromagnetic wave which is slightly modified from the incoming electromagnetic wave.