Abstract: A recording apparatus for recording digital signals corresponding to components of telluric and magnetic fields. The apparatus comprises an analog input stage, a low pass filter stage, an analog output stage, an analog multiplexer and an analog-to-digital converter and recording system for recording the digital signals. A gain computing module is provided as well as a recording selector to achieve variable amplification gains in the analog input and output stages as well as variable frequency bands in the low pass filtering stage to accommodate different frequency input signals for low frequency recording, intermediate frequency recording and high frequency recording.

Abstract: A process for automated regulation of a unit producing sulphur by oxidation of hydrogen sulphide, in which the flow of gas carrying oxygen into the unit is regulated so as to keep an operating parameter, based on measurement of the sulphurous compound of the residual gases, level with a reference value.It is characterized by the fact that the control signal, used to regulate the flow of gas containing oxygen at the unit inlet, is a combination of a signal based on measurements taken at the inlet, and representing the theoretical flow of this gas needed to keep the operating parameter at its reference level and another signal representing the correction needed in this flow to adjust the instantaneous value of the parameter to the reference level.This process allow better control of the sulphur unit, with increased efficiency and reduced atmospheric pollution.

Abstract: A process for automated regulation of a unit producing sulphur by oxidation of hydrogen sulphide, in which the flow of gas carrying oxygen into the unit is regulated so as to keep an operating parameter, based on measurement of the sulphurous compound of the residual gases, level with a reference value.It is characterized by the fact that the control signal, used to regulate the flow of gas containing oxygen at the unit inlet, is a combination of a signal based on measurements taken at the inlet, and representing the theoretical flow of this gas needed to keep the operating parameter at its reference level and another signal representing the correction needed in this flow to adjust the instantaneous value of the parameter to the reference level.This process allow better control of the sulphur unit, with increased efficiency and reduced atmospheric pollution.