ApplicationNo. 05/734424 filed on 10/21/1976
US Classes:175/14, Combustion is confined chamber having restricted discharge orifice266/904, BLOWPIPE CUTTING HEADS431/158Chamber outlet forms jet nozzle
ExaminersPrimary: Purser, Ernest R.
Assistant: Favreau, Richard E.
Attorney, Agent or Firm
International ClassE21B 7/14 (20060101)
Foreign Application Priority Data1976-02-20 DT
AbstractA thermal drilling device which operates in a rotary or circumferentially oscillatory motion and which is particularly adapted for drilling geological formations comprises a drill body which has an interior combustion chamber with a bottom having an outlet defining a discharge nozzle. Means are provided for adding fuel components into the combustion chamber and for igniting them to generate hot gaseous products of combustion which are discharged through a nozzle slot arranged at the bottom of the combustion chamber. The nozzle slot extends diametrically of the drilling area at the bottom and slot outline or a plurality of slots arranged symmetrically relative to the longitudinal axis of the drilling body. In one embodiment the nozzle slot has a radially extending portion with the circumferential width of the slot increasing in a radial outward direction.