Abstract: The method connecting wells by hydraulic-fracturing of a mineral bed, primarily for connection of wells in underground gasification of coal beds; using hydraulic-fracturing of a bed is effected intermediate a source-well into which a liquid is pumped under pressure and a well in the required direction; the head of the well with which connection is to be effected is sealed, whereas the heads of the wells, with which connection is undesirable, are opened; the liquid is pumped into the source-well under a pressure sufficient for initiating hydraulic-fracturing; the pressure in the well with which the source-well is to be connected is measured, and the moment the pressure in this well attains the hydraulic-fracturing value, the head thereof is immediately opened; upon the formation of a hydraulic fracturing fissure, the latter is flushed with the liquid; the method provides for building up a hydraulic-fracturing pressure in the well with which connection of the source-well is to be effected and thus controlling t

Abstract: A heater includes coaxially arranged an external heat radiating shell, a central gas fuel tube and an intermediate perforated air conducting tube, from inside of which air flows into a combustion chamber.A tubular partition is provided with the space in between the air conducting tube and the central gas fuel tube, whereby the initial air flow blowing around and lengthwise of the gas fuel tube is to be turned near the end of this tube to pass to the perforated walls of the air conducting tube.