Abstract: A process for heating at least two metal pipes wherein each pipe is individually preheated in response to sensors detecting its initial temperature and wall thickness. The pipe then passes through a continuous heater which applies an equal amount of energy to each portion of the pipe, after which each pipe emerges having a predetermined temperature independent of both its initial temperature and the wall thickness.

Abstract: An automatic flash-limiting arrangement for use in combination with a flash unit associated with a camera and arranged to automatically terminate the light flash produced by the unit when the subject has been properly exposed, the flash-limiting arrangement being associated with the flash unit so as to become operative only upon initiation of a light flash, thus assuring that the arrangement will not respond to extraneous flashes occurring before the flash which is to be controlled. The flash-limiting arrangement is constructed to sense the light being received by the camera, to produce a signal which is the sum of a component proportional to the time integral of the intensity of such light and a component which is proportional to the instantaneous amplitude of the intensity of such light, and to terminate the flash when this signal reaches a predetermined value.