Abstract: Apparatus for sensing distances between two objects by using multiple pulses from the detector and from the object to be detected by using a transmitter and not using any reflected waves the reliability and the ability to reject clutter is improved. The periods between transmission are accurately controlled so that there is no signal returned until the object to be detected generates such a signal. As a result it is possible to accurately measure the distance between two objects and indeed the system may be used between two objects when both are in motion.

Abstract: A gas-liquid-solids separation system for use with a drilling device includes a surge tank for holding drilling efflux comprising gas, liquid and solids, and adapted for mounting on a drilling device in a position for having a drill shaft extending therethrough. A stuffing box attached to a back side of the surge tank means and configured for enabling passage of the drill shaft therethrough prevents the drilling efflux from escaping the surge tank. A flange attached to the front side of the surge tank and aligned with the stuffing box for allowing passage of the drill shaft therethrough provides a seal between the surge tank and a borehole casing to enable the drilling efflux to flow into the surge tank means. An agitator disposed within the surge tank maintains suspension of the solids within the liquid, and a gas cyclone in fluid communication with the surge tank withdraws gas from the surge tank and separates any entrained liquid therefrom.