Abstract: Breaking rock and concrete, based upon a Controlled-Foam Injection or PCF (Penetrating Cone Fracture) uses a high-pressure fluid to pressurize a pre-drilled hole. A high pressure seal is formed between the injection barrel and walls of the pre-drilled hole in the material to be broken. A leak-free poppet valve holds a fluid in a pressure vessel before rapid discharge. Variable charges of foam/water are generated and delivered to the breaker. The injection barrel is prefilled with a low viscosity fluid. An annular reverse acting poppet valve allows concurrent injection of chemical additives and/or micro particles to modify foam viscosity during its high pressure release into the material to be broken. A high pressure foam generator is compact and reliable. Removal and wash-out of the seal frees the injection barrel.

Abstract: Breaking hard compact materials, such as rock and concrete, is based upon a controlled-fracturing process. A high-pressure foam is used to pressurize a predrilled hole of appropriate geometry. The high-pressure foam is delivered to the bottom of the drilled hole by a barrel inserted into the hole. The barrel includes a seal near the bottom of the hole. By restricting and controlling the pressure of the high-pressure foam to the bottom of the hole, a controlled fracturing is achieved which results in the fracturing and removing of a large volume of material at a low expenditure of energy. The foam-injection method produces almost no fly rock or airblast. The foam-injection method may be used to fracture, remove and/or excavate any hard material such as rock or concrete. The method may be used in either dry or water filled holes and the holes may be in any orientation. The foam injection apparatus is carried on a boom mounted on a carrier.

Abstract: Breaking hard compact materials, such as rock and concrete, is based upon a controlled-fracturing process wherein a high-pressure foam is used to pressurize a pre-drilled hole of appropriate geometry. The high-pressure foam is delivered to the bottom of the drilled hole by a barrel inserted into the hole. The barrel includes an end seal for sealing near the bottom of the hole. By restricting and controlling the pressure of the high-pressure foam to the bottom of the hole, a controlled fracturing is achieved which results in the fracturing and removing of a large volume of material at a low expenditure of energy. The foam-injection method produces almost no fly rock nor airblast. The foam-injection method may be used to fracture, remove and/or excavate any hard material such as rock or concrete. The method may be used in either dry or water filled holes and the holes may be in any orientation. The foam injection apparatus is carried on a boom mounted on a carrier.

Abstract: Rock and other hard materials, such as concrete, are broken by a controlled-fracturing process referred to as penetrating-cone fracture. The fracturing process is accomplished by pressurizing the bottom of a drill hole in such a way as to initiate and propagate a controlled fracture from the sharp hole-bottom corner while not crushing the surrounding rock. A cartridge containing a propellant charge is inserted at the bottom of a short hole drilled in the rock. The cartridge is stemmed by a massive bar. A firing pin in the stemming bar strikes a primer which then ignites the propellant in the cartridge. The cartridge incorporates a relief volume designed to control propellant burning rates and pressures and thus the pressure at the hole bottom. The cartridge is designed with a tapered wall, which is thicker nearer the stemming bar, and with a large radius of the inside surface of the cartridge base, which reduce the possibility for premature cartridge rupture and loss of propellant generated gases.

Abstract: Hard compact materials, such as rock, concrete, et cetera, are broken by igniting an appropriately designed explosive or propellant charge placed within the hole or carried in a special charge-containing device with a short barrel which is inserted and sealed into a pre-drilled hole of particular geometry. One or more approximately cylindrical holes are drilled into the material to be broken by conventional drilling, such as used in the mining and construction industries. The holes have a relatively short depth to diameter ratio, being in the range of about 2:1 to 6:1, and preferably about 3:1 to 5:1. The holes are percussively drilled with microfractures in and around hole bottoms to provide fracture initiation sites at the hole bottoms so as to provide preferred fracture initiation roughly parallel to a free surface of material being excavated.

Abstract: A device generates pulsed liquid jets through a cumulative nozzle at high repetition rates by using a controlled oscillatory motion of the nozzle assembly coupled with the inertia of the water package and a piston to effectively evacuate the nozzle prior to generation of each jet pulse. The cumulative nozzle can be of any form, such as exponential, hyperbolic, cissoid, etc. Forward motion of the nozzle assembly serves to empty the nozzle of liquid residual therein from the previously generated jet. That forward motion also positions the residual liquid, freshly added liquid and a liquid accelerating piston for the generation of the next subsequent pulse. At the end of the forward motion stroke, the liquid and accelerating piston are rapidly accelerated into the nozzle by means of a high pressure gas.

Abstract: A hard compact material such as rock is broken by directing a high velocity jet of relatively incompressible fluid, such as water, into a hole which is drilled in the material to be broken. The jet is generated by a nozzle in alignment with the hole and is suddenly arrested in the hole in appropriate position with respect to adjacent free surfaces of the material. A jet stagnation pressure is created in the hole of sufficient magnitude and duration or jet repetion rate to break the material towards the free surfaces. Preferably, a secondary nozzle emits fluid for filling partially or wholly the hole prior to generating the high velocity jet by a primary nozzle.