WATER-PISTOL ROCK BUSTER TUNNELS THROUGH HARDEST ROCK
AN EFFECTIVE TECHNIQUE WAS DEVELOPED BY THE ALUMNI INSTITUTE OF TRANSPORTATION RESEARCH INSTITUTE, CHICAGO, TO GENERATE PULSES OF EXTREME WATER PRESSURE BY CONTINUOUSLY TRIGGERING A SERIES OF NITROGEN-POWERED INTENSIFIERS. THE NITROGEN-TO-WATER INTENSIFIER IS PRE-LOADED WITH OIL AGAINST THE PRESSURE OF THE NITROGEN. THE MULTIPLE VALVES DUMP THE OIL TO INITIATE THE CYCLE. BY THIS MEANS, IT IS SUGGESTED THAT 20-FT-DIA TUNNELS CAN BE BORED THROUGH HARD ROCK AT 10 FT/HR. THE INSTITUTE HAS WRITTEN SPECIFICATIONS FOR TUNNELING MACHINES BASED ON THE PRINCIPLE. THREE FLUIDS ARE INVOLVED: WATER, OIL, AND NITROGEN. AN ACCUMULATOR SUPPLIES NITROGEN UNDER PRESSURE TO THE LARGE END OF THE FREE PISTON IN THE INTENSIFIER. OIL, SUPPLIED BY A PUMP, PRESSURIZES THE OPPOSING FACE OF THE LARGE PISTON AND DRIVES IT BACK AGAINST THE PRESSURE OF THE NITROGEN, THUS COCKING THE INTENSIFIER. IN OPERATION, A LARGE NUMBER OF DUMP VALVES RELEASE THE OIL PRESSURE INSTANTLY, AND THE NITROGEN PRESSURE FORCES THE PISTON FORWARD RAPIDLY. THE SMALL PISTON DRIVES THE CHARGE OF WATER THROUGH A SPECIAL NOZZLE.
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Supplemental Notes:
- Vol 41, No 18, P 37, FIG
- Publication Date: 1970-8-31
Media Info
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Serial:
- Product Engineering
- Publisher: McGraw-Hill, Incorporated
Subject/Index Terms
- TRT Terms: Nitrogen; Oils; Pistons; Rock drilling; Water; Water pressure; Waterjets
- Subject Areas: Construction; Highways;
Filing Info
- Accession Number: 00215354
- Record Type: Publication
- Files: TRIS
- Created Date: Nov 3 1970 12:00AM