EP0251660A1 - Procédé et dispositif d'excavation du sol ou similaire - Google Patents

Procédé et dispositif d'excavation du sol ou similaire Download PDF

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Publication number
EP0251660A1
EP0251660A1 EP87305583A EP87305583A EP0251660A1 EP 0251660 A1 EP0251660 A1 EP 0251660A1 EP 87305583 A EP87305583 A EP 87305583A EP 87305583 A EP87305583 A EP 87305583A EP 0251660 A1 EP0251660 A1 EP 0251660A1
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EP
European Patent Office
Prior art keywords
valve
nozzle
gas
air
bore
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP87305583A
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German (de)
English (en)
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EP0251660B1 (fr
Inventor
Aubrey C. Briggs
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Air Technologies Inc
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BRIGGS Tech Inc
Air Technologies Inc
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Publication date
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Priority to AT87305583T priority Critical patent/ATE82027T1/de
Publication of EP0251660A1 publication Critical patent/EP0251660A1/fr
Application granted granted Critical
Publication of EP0251660B1 publication Critical patent/EP0251660B1/fr
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/88—Dredgers; Soil-shifting machines mechanically-driven with arrangements acting by a sucking or forcing effect, e.g. suction dredgers
    • E02F3/90—Component parts, e.g. arrangement or adaptation of pumps
    • E02F3/92—Digging elements, e.g. suction heads
    • E02F3/9206—Digging devices using blowing effect only, like jets or propellers
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/88—Dredgers; Soil-shifting machines mechanically-driven with arrangements acting by a sucking or forcing effect, e.g. suction dredgers
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F5/00—Dredgers or soil-shifting machines for special purposes
    • E02F5/28—Dredgers or soil-shifting machines for special purposes for cleaning watercourses or other ways
    • E02F5/287—Dredgers or soil-shifting machines for special purposes for cleaning watercourses or other ways with jet nozzles

Definitions

  • THIS INVENTION relates generally to the excavation of soil and other granular materials by a high velocity gas stream. More particularly, the invention relates to a method and apparatus utilizing a stream of gas, preferably air, for the excavation of granular materials such as soil around buried objects.
  • the present invention is particularly suited for excavation in close proximity to and in contact with subterranean utility lines, conduits and the like where conventional mechan­ical and hand excavation techniques could cause damage to the buried pipes, wires or cables and, in some cases, create explosion hazards.
  • the cleaning mechanism itself can damage the surface of the object being cleaned and a scraper or hoe can gouge or destroy a pipe or valve if the mechanism controlling the device is inadequate or improperly set.
  • liquid hydraulic sprays such as water
  • the disadvantages are also manifest. A large supply of water is usually required, which creates a disposal problem at the job site.
  • the splashing of the water spray must be contained and generally coats surrounding equipment with a layer of mud. In cold weather operations, the water must be treated with an antifreeze or some other fluid must be employed so as to eliminate icing problems.
  • This invention seeks to solve many of the problems heretofore encountered in excavating around buried utility lines, pipe, conduits and the like, or for excavating to and in contact with fragile objects or structures, such as building foundations, which may be damaged by mechanized digging equipment.
  • a method of moving or dislodging a soil mass or similar granular material mass to effect excavation or cleaning comprising the steps of direct­ing, at said soil mass or like granular material mass a jet of gas having a velocity greater than Mach 1.
  • the velocity of the gas is greater than Mach 1.5 and most preferably greater than Mach 3.
  • the gas stream is obtained from a source of gas having a pressure greater than 620 KNm ⁇ 2g.
  • the gas stream has incorporated in it, prior to the gas stream being accelerated to supersonic speed, a substance which solidifies on cooling, the acceleration causing the said substance to solidify to form particles which may provide an add­itional abrasive effect.
  • an apparatus for dislodging a soil mass or a similar granular material mass to effect excavation or cleaning comprising a source of pressurized gas, a duct, communicating with said source of pressurized gas and a nozzle wherein the nozzle is of the converging/diverging type having a throat section and an outlet section each of said sections defining a respective cross-sectional area, the ratio of the outlet section area to the throat section area being greater than 1.0 whereby said apparatus is adapted, in use, to produce a stream of gas at a velocity of greater than Mach 1 when pressurized gas from the reservoir passes through the nozzle.
  • the apparatus comprises means for introducing, into the duct, upstream of the nozzle, a liquid or gaseous material which solidifies on cooling.
  • valve means are provided, assoc­iated with the duct means, adapted to regulate the flow of gas from the gas source to a nozzle
  • the valve means comprising a valve body having a bore therethrough, positioned in communication with said duct and with source of gas
  • said valve means further including a valve member having a head portion and a piston portion inter­connected by a stem said head portion cooperating with a valve seat to cut off the supply of pressurized gas to said nozzle when said valve is in a deactivated position
  • said valve means further including a pilot bore adapted to communicate between the source of pressurized gas and the piston portion of the valve when said valve means is in an activated position, whereby said pressurized gas is adapted to pass through said pilot bore means to act on said piston portion to move said valve member and cause said head portion to unseat and permit the flow of pressurized gas to the nozzle.
  • valve means includes trigger means including a rotatable cylindrical portion having a pilot port therethrough which is adapted to communicate with said pilot bore means where said trigger means is in an activated position to permit pressurized gas to flow therethrough to unseat said valve head, and adapted to close off said pilot bore means when said trigger means is in a deactivated position.
  • the cylindrical portion of the trigger means also has a vent port formed therein to permit the escape of pressureized gas from the pilot bore means to the atmosphere when the trigger means is moved to the deactivated position.
  • the present inven­tion is directed to a method and apparatus for excavating in and around these relatively fragile components which employs a jet-like stream of a gas, preferably air, at supersonic flow rates to provide a fast, efficient, and safe technique in this heretofore tedious task.
  • the invention is suitable for use in the form of a hand-held tool or it may be frame mounted on an excavating machine or used in conjunction with an automated robotic excavator apparatus.
  • the invention provides a supersonic jet of air which creates fissures and cavities when directed to a soil mass or to a mass of like granular material.
  • the impacting, high-velocity air stream becomes instantaneously trapped or stagnated within these soil cavities, causing rapid fracture of the local sites due to the large momentum flux which results from the rapid release of the expanding high pressure air trapped within the cavities and fissures.
  • the stagnated or trapped air must expand and, in doing so, causes the soil to fail in tension, its weakest attribute.
  • a preferred embodiment of the invention comprises a device for safely excavating soil in close proximity to gas lines, water pipes, sewer lines, under­ground power cables, telephone lines and the like, which is very selective in its attack.
  • the supersonic air stream provided is extremely agressive toward soil while being completely harmless towards buried objects, including those of a very fragile nature, such as under­ground television or telephone cable.
  • the present invention provides a supersonic air jet, preferably about 11 ⁇ 2 to 3 times the speed of sound or higher, depending upon the operating pressures and nozzle diameters employed.
  • the jet impacts upon surfaces, penetrates and breaks up the soil mass while being deflected by impervious surfaces such as plastic or iron pipe or electrical cable and conduit.
  • impervious surfaces such as plastic or iron pipe or electrical cable and conduit.
  • a preferred embodiment of the invention comprises an excavating or cleaning device which is simple to operate and safe to use and which is operable with standard commercial air compressors.
  • the device of the present invention provides a high velocity gas stream capable of penetrating and fragmenting a wide range of soil types, from very hard and brittle, such as dry baked clay, to soils which are very rubbery or sticky.
  • the device produces a supersonic jet which is effective at practical standoff distances from the nozzle, making it easy to operate when embodied in the form of a hand-held device.
  • a hand-operated embodiment of the present invention may incorporate a unique, low-torque trigger valve mechanism which employs the reservoir gas at high pressure as a pilot to assist in opening the valve to the high pressure supply line.
  • the valve body and covers provide a sealed environment against dust, mud and water or other hostile environments making it suitable for the demanding service experienced in the field.
  • small amounts of liquid water or gaseous CO2 may be introduced into the device to produce an entrained flow of solid particles within the supersonic air stream to provide an abrasive cleaning action to the high speed jet.
  • Various embodiments of the present invention may provide devices which are capable of pro­ducing supersonic gas streams of various cross-­sectioned configurations depending upon the shape of the nozzle employed. Circular or square nozzles are preferred in excavation applications, while a thin, knife-like rectangular nozzle is particularly suited for cleaning operations, such as in cleaning caked sub­stances from bulk material conveyor belts.
  • a reservoir of pressurized gas preferably air, maintained at about 620 to 689 KNM ⁇ 2 (90-100 psig) or higher, provides a flow of gas which is regulated through appropriate valve means to a barrel of the device which is fitted with a converging/diverging nozzle at the end of the bore thereof.
  • the nozzle may possess a circular cross-section or a square or rectang­ular cross-section, depending upon the shape of the air jet desired.
  • the converging/diverging configuration of the nozzle is critical in the creation of the supersonic air jet in accordance with known principles of fluid mechanics.
  • the boundary conditions of supply pressure and ambient or atmospheric pressure produce a choked sonic flow condition at the throat of the nozzle and a supersonic flow in the diverging section.
  • the diverging section is flared such that the air accelerates smoothly, without shock waves, to produce a maximum velocity and Mach number at the nozzle outlet.
  • the choked flow condition is a known phenomenon and occurs when the fluid mass flow rate attains a maximum value for a given throat area of the nozzle at given upstream conditions of temperature and pressure.
  • the flow rate at the exit of the converging/­diverging nozzle thus can be predicted by closely con­trolling the area ratio of the throat and outlet regions of the nozzle, along with the pressure ratio of the air within the reservoir with that of the ambient pressure, normally atmospheric.
  • a gas stream velocity greater than just supersonic is required and, more particularly, a velocity at least about Mach 2 is preferred since it provides a more efficient digging tool.
  • a nozzle for producing an exit velocity of Mach 2 employs an area ratio of about 1:1.685 outlet area to throat area, and a pressure ratio of about 7.8:1, reservoir pressure to ambient pressure.
  • a Mach 2 exit velocity is feasible utilizing a conventional air compressor which usually is capable of generating between 620 to 758 KNm ⁇ 2 (90 to110 psi) reservoir pressure at a sufficient flow rate of, for example, 3.5 cubic metres (125 cubic feet) per minute of air.
  • a trigger actuated valve normally spring-biased to a closed or deactivated position, is provided to pilot flow of high pressure reservoir air around the valve to assist in overcoming the force of the pressurized reservoir air which normally maintains the valve in the closed position.
  • the valve member comprises a valve stem positioned within the bore of a valve body or housing having a valve head positioned in sealing engagement with a valve seat at an inlet end which is in communication with the pressurized inlet air.
  • the valve also includes a second end carrying a piston of a larger diameter than the valve head.
  • An air inlet bypass bore is formed within the valve body of the handle member, communicating at a first end with the pressurized air channel upstream of the valve head and communicating at its second end with an interior space of the valve housing adjacent to the piston.
  • a rotatable trigger shaft Positioned in a space between the first and second ends of the air inlet bore is a rotatable trigger shaft which has a bore formed through its diameter which communicates with the aforementioned air inlet bore when the trigger shaft is rotated to a "firing" or activated position.
  • the pressurized air from the inlet is fed to the spaced adjacent to the larger diameter piston causing the valve to unseat instantly, permitting the pressurized air from the reservoir to pass through the valve body into the bore of the barrel and thence to the converging/diverging nozzle.
  • the trigger mechanism is spring-biased to return to the closed position when the operator releases his grip thereon.
  • the trigger shaft is also provided with a vent orifice which com­municates with the air inlet bore on the piston side thereof to permit the venting of the by-pass bore when the trigger is returned to its close position.
  • an air pressure gauge is also preferably provided on the excavator device to insure that proper operating air pressure is maintained.
  • the device is also preferably constructed of a noncorrosive and non­ferrous material so that the device is rust resistant and also nonsparking to render it suitable for use in potentially explosive environments.
  • the barrel may also be provided with an elongated pick element, outwardly projecting beyond the nozzle, to permit the operator to dislodge any stubborn lumps of material during the excavating operation.
  • the barrel of the device may be either a straight length of pipe or it may be fitted with a curved exit section for difficult-to-reach applications.
  • the present invention In addition to permitting excavation around various utility service lines to be effected quickly and safely, the present invention also has application in trenching; clearing plugged silos and chutes; excav­ating under sidewalks and roads; digging under found­ations for underpinning; for cleaing out road potholes prior to patching; and for digging post holes in difficult terrain, and the like.
  • a reservoir of compressed gas preferably air
  • the flow of pressurized air is controlled and directed through appropriate duct or bore means to a converging/diverging nozzle positioned at the discharge end of the duct or bore.
  • the converging/diverging nozzle includes a restricted throat section and a diverging section which terminates in an outlet section.
  • the ratio between the cross-sectional area of the outlet section and the cross-sectional area of the throat section of the nozzle being greater than 1.0 and, preferably, greater than about 1.2, while the ratio of reservoir pressure to exit pressure is greater than about 1.9 and, preferably greater than about 3.7, whereby an air jet exits the nozzle, having a calculated isontropic velocity of greater than Mach 1.0 and, pre­ferably, greater than Mach 1.5.
  • the supersonic air jet is directed to a soil mass or the like, whereupon the jet penetrates the mass, stagnates, then expands and fractures the material.
  • Liquid water or gaseous CO2 may be introduced into the air stream upstream of the nozzle to produce ice particles or solid CO2 particles entrained in the supersonic air jet as a result of a rapid temperature incursion when these materials pass through the nozzle.
  • a hand operated excavator device is shown and designated generally by the reference numeral 2 therein.
  • the excavator device 2 is suited for manual excavation of buried utility lines, such as the utility pipe or conduit 22 or the television, electrical, tele­phone or like cable 22 ⁇ shown in Figure 8.
  • the device 2 is operably connected by way of a high pressure air hose 16 to a storage reservoir of high pressure air generated by compressor 20.
  • the air compressor is preferably of a conventional type normally used in construction work and capable of delivering 3.5 cubic metres (125 cubic feet) per minute of air at a reservoir pressure of at least 620 KNm2g (90 pounds per square inch gauge (psig)) at the outlet.
  • the air hose 16 preferably has a minimum inside diameter of about 2.54 cms (1 inch) in order to handle the air volume required for the intended excavating purposes.
  • Device 2 is operably connected to the air hose 16 by way of a conventional quick disconnect coupling 18 which may be threadably fitted to the handle member 10 at the base of conduit 24. (see Figures 2 and 3).
  • the device 2 further includes a control valve body 4 with a trigger mechanism 12 for controlling the flow of high pressure air therethrough.
  • the device 2 also includes a con­verging/diverging nozzle 50 fitted within a bore 7 of barrel 6 at the outlet end 8 thereof.
  • a con­verging/diverging nozzle 50 fitted within a bore 7 of barrel 6 at the outlet end 8 thereof.
  • the ratio of the outlet diameter to throat diameter of the nozzle 50, at a given supply pressure of air from the compressor 20, will produce a choked sonic flow condition at the nozzle throat and supersonic air flow in the diverging section at the outlet of the nozzle 50 which provides the required energy for excavating.
  • the device 2 also preferably contains a handle 14 for convenient gripping by the operator and also a pressure gauge 21 mounted on the rear face of the valve body 4 to enable observation of the operating air pressure.
  • valve mechanism for regulating the flow of high pressure air through the hand operated excavation device 2 is depicted in Figures 2, 3 and 4.
  • the conduit 24 has a bore 25 which communicates with air hose 16 and with the high pressure air within the reservoir generated by compressor 20.
  • Conduit 24 is fitted within handle 10 and attached to the valve body 4 by way of threads, soldering, or the like to create an airtight fit therewith.
  • Valve body 4 has an internal bore 5 extending therethrough in a generally T-shaped config­uration from the inlet end adjacent conduit 24 to the outlet end adjacent the barrel 6.
  • Barrel 6 has a bore 7 which is also in communication with the bore 5 of the valve body.
  • Barrel 6 is rigidly attached to the valve body 4 in an airtight manner by sleeve fitting 82 which is secured by way of threaded section 83 to the valve body 4.
  • a pair of O-rings seals 84 and 86 are provided around the sleeve fitting 82 and the barrel 6 to provide a mechanically strong and airtight seal.
  • Valve 28 includes a head portion 30 having a tapered edge which sealably engages the seat 34 of a venturi-type sleeve 32 which is seated within the bore 5.
  • Sleeve 32 has a cylindrical bore formed therethrough which is sealed off when the valve 30 is in the closed position shown in Figure 2. In the closed position, the tapered edge of the valve head 30 sealably engages tapered valve seat 34 to prevent pressurized air from entering the barrel bore 7.
  • a generally cylindrical piston 38 is mounted on valve stem 36 of the valve 28 at the opposite end from the head 30.
  • Piston 38 is slidably positioned within a chamber 80 formed within the upper portion of the valve body 4 and is secured to the valve stem 36 by a nut and washer 40.
  • the piston 38 also preferably contains an annular cutout portion 44 formed in the underside thereof to receive a coil spring 42 therein.
  • a cylindrically shaped valve guide 46 is fitting within the valve body 4 and tightly receives the valve stem 36 therethrough.
  • An O-ring 48 is fitted within the valve guide 46 to prevent air leakage around the moving valve stem which slidably moves therein.
  • the coil spring 42 compressively engages the top of the valve guide 46 and the bottom of the piston 38 within portion 44 to bias the valve 28 and the attached head portion 30 to a closed position against the sealing seat 34 of the sleeve 32.
  • An O-ring 47 is also provided around the periphery of the piston 38 to minimize air leakage therearound.
  • valve head 30 In the closed position depicted in Figure 2, the valve head 30 is firmly held in place against the valve seat 34 by the high pressure in the bore 25.
  • the area of the valve head 30 is 6.45 sq cms (1 square inch) and the inlet pressure within the bore 25 is 689 KNm ⁇ 2g (100 psig), then a force of greater than 45 Kg (100 pounds) is required to unseat the valve head 30 to permit air to enter into the bore 7 of the barrel 6.
  • a control valve is provided which is operated by pilot air pressure from the main air supply within the conduit 25.
  • the pilot air flow is controlled by movement of the trigger mechanism 12 which is ported to selectively permit the air to enter the exhaust depending on the position of the trigger 12.
  • the valve body 4 has a small diameter air inlet bore 62 formed therein which communicates with the bore 5 at one end thereof and is adapted to communicate with a first end of bore 64 formed in the cylindrical trigger shaft 26.
  • the trigger When the trigger is in the deactivated position shown in Figure 2, the bore 64 does not communicate with the bore 62; hence, no pressurized pilot air is supplied to open the valve 28.
  • the trigger 12 and its integral shaft 26 rotate in a counterclockwise direction to align the bores 62 and 64 to permit the flow of pilot air therethrough.
  • the valve body 4 also contains a bore 66 which is formed therein to communicate with the second end of bore 64 of the trigger shaft when the trigger 12 is in the activated position.
  • Bore 66 communicates with a vertically extending bore 68 also formed within the body 4 which, in turn, communicates with a transversely extending bore 70 which communicates with circum­ferentially extending grooves 72 which are formed around the cylindrical outer sidewall of the sleeve 32 which, thence, communicate with a bore 74.
  • Bore 74 commun­icates with a bore 76, also formed within the valve body 4, which, in turn, communicates with a passage 78 near the top of the valve body 4. Passage 78 communicates with the chamber 80 above the piston 38 of the valve 28.
  • valve head 30 The surface area of the face of piston 38 which is exposed to chamber 80 is greater than that of the valve head 30.
  • pilot air at line pressure, is supplied through bores 62, 64, 66, 68, 70, 72, 74, 76, 78 to the chamber 80.
  • Chamber 80 is likewise contained within an airtight closure by way of a threaded cap 45 and an O-ring seal 49 affixed to the valve body 4.
  • the pressurized pilot air supplied through the activation of the trigger 12 will cause the immediate downward movement of the valve 28 due to the unbalanced forces acting on the valve. Movement results from the fact that the surface area of the piston 38 is greater than that of the valve head 30.
  • Downward movement of valve 28 causes the valve head to unseat and permits the pressurized air from compressor 20 within the bores 25 and 5 to enter into the bore 7 of the barrel 6, and, thence, to the nozzle 50 and outlet 8 of the device 2.
  • the pressurized air within the chamber 80 is vented through the aforementioned bores 78, 76, 74, 72, 70, 68, 66 and, thence, through bores 87 and 88 formed within the trigger shaft 26 which, in turn, communicate with a bore 89 formed within the valve body 4.
  • the pressurized air within the chamber 80 above the piston 38 is instantaneously vented to the atmosphere when the trigger mechanism is deactivated to permit the valve head 30 to instantaneously move upwardly to seat against the sealing surface 34 of the sleeve 32 to halt the air flow through the device 2.
  • the trigger mechanism 12 and trigger shaft 26 are biased outwardly in the de­activated position by way of a torsion spring 27 which is attached to the trigger shaft 26.
  • Pressurized air leakage from the bores 64 and 70 is minimised through a plurality of O-rings 33, 35 and 35 ⁇ which are fitted within slots formed in the periphery of the trigger shaft 26 to sealably engage against seating bore 37 formed within the valve body 4.
  • a pair of cover plates 29 and 29 ⁇ are secured to the valve body 4 by way of threaded fasteners 31. The plates 29, 29 ⁇ seal the trigger shaft 26 and bore 64 of the valve mechanism against the environment.
  • valve body 4 also is fitted with a conventional air pressure gauge 21 which is mounted at the rear face of the body 4, operably attached to a bore 23 which communicates with the interior 5 of the valve body to permit the operator to monitor the line pressure when the device 2 is in use. If the pressure drops below a certain value, for example, 620 KNm ⁇ 2g (90 psig) the operator is alerted to take corrective action to ensure that the air compressor is operating properly.
  • a certain value for example, 620 KNm ⁇ 2g (90 psig) the operator is alerted to take corrective action to ensure that the air compressor is operating properly.
  • valve body 4 The materials of construction of the valve body 4, the internal valve components and trigger assembly, as well as the barrel 6, are preferably of non-corrosive materials such as cast bronze, stainless steel, or high impact plastic. In situations where sparks may create an explosion hazard around natural gas fumes, the barrel 6 as well as the tip 58 may be constructed of a non-­ferrous, non-sparking material such as bronze.
  • the gripping portions of the device 2, handles 10 and 14, may be constructed of a hard rubber, plastic, hard wood, or like material.
  • the outlet end 8 of the supersonic excavator device 2 may be provided with variously shaped fittings suitable for the particular work involved.
  • Figures 1 and 5 show the outlet end 8 fitted with a pick-like tip 58 to permit the operator to loosen lumps of unusually stubborn material with the sharpened tip thereof.
  • the barrel 6 may be straight or it may contain a curved or angled section 60 at the outlet end 8 thereof as shown in Figure 7.
  • the curved section 60 provides additional manoeuverability in the device for difficult to reach tunneling applications and in areas beneath pipes and conduits.
  • the converging/diverging nozzle 50 is firmly attached, as for example, by silver solder or fine threads, to the end of the barrel 6 such that the inlet end 52 of the converging section of the nozzle smoothly blends with the bore 7 of the barrel.
  • the converging section gradually tapers to a throat section 54 which presents the minimum diameter within the nozzle.
  • the nozzle then gradually increased in diameter to terminate at an outlet portion 56.
  • the nozzle 50 has a reduced outer diameter section 51 near its inlet end 52, which is snugly received within the bore 7 of the barrel 6. If the pick-like tip 58 is employed, as in Figure 5, the nozzle 50 has a second reduced outer diameter section 53 formed around the outlet end 56 thereof, to permit the attachment of the tip 58 thereto. Attachment can be made by a solder or threaded joint or the like.
  • the maximum flow rate for an ideal gas in friction­less adiabatic or isotropic flow (without heat addition or substraction) through a converging nozzle is at a Mach number of one, which occurs at the minimum section, i.e. at the throat of the nozzle.
  • the Mach number is defined herein as the ratio of velocity of the air jet at the outlet 56 of the nozzle 50 to the velocity of sound at that point. It is also known that supersonic flow will occur if the nozzle area downstream from the nozzle throat increases, thus forming a converging/­diverging nozzle of the type employed in the present invention.
  • a gas stream such as air travelling at a velocity greater than Mach 1 provides a surprisingly effective medium for excavating soil or other granular materials due to its ability to create and infiltrate small fissues and cavities therein. It is hypothesized that the super­sonic jet penetrates the soil structure until complete stagnation occurs within these local cavities which, in effect, act as reservoirs for the momentary storage of high pressure, decelerated air. The stagnated air must then expand and, in so doing, causes the soil to fracture in tension, its weakest directional attribute. These local reservoir sites of high pressure provide the energy source for the final fracture of the material in tension and the nearly instantaneous initiation of a pneumatic explosion due to the rapid expansive release of high pressure air to the atmosphere.
  • the present invention provides a method and apparatus for transferring the pressure energy produced by the air compressor 20 to a local excavation site where its destructive power is utilised and further provides, through its large momentum flux, the aforementioned cavities for the instanteous storage and release of such pressure energy.
  • Nozzle 50 is circular in cross section and includes an inlet 52 having a bore diameter equal to that of the barrel 7 which may, in this example, be about 2.22 cms (0.875 inch).
  • the nozzle profile then converges to the throat section 54, with a diameter "A" of, for example, 0.64 cms (0.250 inch).
  • the nozzle bore then gradually expands in the diverging section 55.
  • dimension "D” may be 0. 68 cms (0.269 inch) where "E” is equal to 0. 44cms (0.172 inch).
  • the illustrative nozzle outlet 56 diameter is represented by dimension "B" which is 0.
  • FIGS 11 and 12 depict a nozzle 94 which is capable of producing a rectang­ularly shaped, supersonic air stream which finds applic­ation in cleaning flat surfaces, as for example, conveyor belts which transport bulk materials.
  • Nozzle 94 includes a body 95 with tapered side plates 102 and 102 ⁇ with a tapered divider plate 104 disposed there­between. The plates 102, 102 ⁇ and 104 are held in place by cover plates 101 and 103 which are secured by fasteners 106.
  • the tapered plates 102 and 104 form a converging nozzle section 98, a throat at 96 and a diverging section which terminates at outlet 100.
  • An identical shape is formed adjacent thereto by tapered plates 102 ⁇ and 104 with a rectang­ularly shaped jet of air emitted from outlet 100 ⁇ .
  • the side by side jets exiting from outlets 100 and 100 ⁇ would merge together a short distance from the nozzle to provide a single, thin knife-like profile ideally suited for cleaning operations where soil or other caked or lodged materials must be removed from flat surfaces.
  • the same ratios of outlet area to throat area apply to the rectangular nozzle 94 as previously discussed in relation to the circular nozzle 50.
  • a substance which solidifies upon cooling such as liquid water or gaseous carbon dioxide
  • a substance which solidifies upon cooling such as liquid water or gaseous carbon dioxide
  • a water mist or stream of gaseous carbon dioxide from passage 59 is entrained within the air stream and is nearly instantaneously solidified as it passes through the converging/diverging nozzle 50 ⁇ due to the great temperature decrease which naturally occurs as the air stream is accelerated through the nozzle. Ice particles or solid CO2 particles are then emitted with the high velocity jet of air to provide an additional abrasive aid in excavating and cleaning applications.
  • the terms "excavating” and “cleaning” may be used interchangeably with respect to the intended use environment for the invention. It can be appreciated that carbon dioxide is a unique add­itive since it presents no residue or disposal problems after it desolidifies.
  • the hand-operated device 2 can be modified so as to be fitted on a piece of mechanized digging equip­ment such as a backhoe or the like. It is also under­stood that apparatus according to the present invention can be incorporated into automated robotic digging equipment, for which the invention is particularly suited. In such applications, it would, of course, be desirable or necessary to modify the valve mechanism from hand-actuated to a pneumatic, hydraulc or like actuation means.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Load-Engaging Elements For Cranes (AREA)
  • Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
  • Earth Drilling (AREA)
  • Nozzles (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Soil Conditioners And Soil-Stabilizing Materials (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
  • Cleaning In General (AREA)
EP87305583A 1986-06-23 1987-06-23 Procédé et dispositif d'excavation du sol ou similaire Expired - Lifetime EP0251660B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87305583T ATE82027T1 (de) 1986-06-23 1987-06-23 Verfahren und vorrichtung zum ausheben von boden und dergleichen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US87728086A 1986-06-23 1986-06-23
US877280 1986-06-23

Publications (2)

Publication Number Publication Date
EP0251660A1 true EP0251660A1 (fr) 1988-01-07
EP0251660B1 EP0251660B1 (fr) 1992-11-04

Family

ID=25369625

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87305583A Expired - Lifetime EP0251660B1 (fr) 1986-06-23 1987-06-23 Procédé et dispositif d'excavation du sol ou similaire

Country Status (7)

Country Link
EP (1) EP0251660B1 (fr)
JP (1) JPS634130A (fr)
AT (1) ATE82027T1 (fr)
AU (1) AU593600B2 (fr)
DE (2) DE3782458T2 (fr)
ES (1) ES2035862T3 (fr)
FR (1) FR2600373B1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4991321A (en) * 1990-06-21 1991-02-12 M-B-W Inc. Pneumatic device for excavating and removing material
EP0442589A1 (fr) * 1990-01-30 1991-08-21 Rindfleisch, Hans-Joachim, Dr. Procédé et dispositif pour créer des tranchées stables dans la terre et/ou le terrain non consolidé
GB2245295A (en) * 1990-06-21 1992-01-02 Mbw Inc High velocity pneumatic device
EP0496481A2 (fr) * 1991-01-25 1992-07-29 The Charles Machine Works Inc Excavateur pour excaver sans dégats
GB2252776A (en) * 1991-02-14 1992-08-19 British Gas Plc Formation of a cavity in the ground
FR2702515A1 (fr) * 1993-03-11 1994-09-16 Simon Henri Procédé et installation pour réalisation de travaux de terrassements notamment excavation en milieu encombré sensible.
US5966847A (en) * 1996-03-14 1999-10-19 Concept Engineering Group, Inc. Pneumatic excavator
US6158152A (en) * 1996-03-14 2000-12-12 Concept Engineering Group, Inc. Pneumatic excavator
WO2005002735A3 (fr) * 2003-06-30 2006-06-15 John Redding Ameliorations apportees ou se rapportant a des ecoulements liquides tourbillonnaires et a des jets de liquide
CN108824526A (zh) * 2018-05-30 2018-11-16 广东知识城运营服务有限公司 一种基于水利工程用环保清淤装置
CN117071678A (zh) * 2023-09-15 2023-11-17 中交广州航道局有限公司 一种非接触法管道疏浚土处理装置及其处理方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001264199A (ja) 2000-03-21 2001-09-26 Katsuyuki Totsu トルク検出器用ビット・アダプタ
DE102016224362A1 (de) * 2016-12-07 2018-06-07 Martin Herz Vorrichtung und Verfahren zur Fugenreinigung
JP7193406B2 (ja) * 2019-04-03 2022-12-20 鹿島建設株式会社 空気掘削具
CN114481790B (zh) * 2022-03-18 2023-05-23 栗欢 一种道路桥梁伸缩缝施工用切割装置及其使用方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR682517A (fr) * 1929-01-19 1930-05-28 Perfectionnements aux procédés d'extraction des sables et autres matériaux dans les bancs noyés
US2413561A (en) * 1945-09-26 1946-12-31 Frederick G Hehr Portable excavating and ejecting machine
FR2096630A1 (fr) * 1970-01-05 1972-02-25 Commissariat Energie Atomique
US3917007A (en) * 1973-06-07 1975-11-04 Mikhail Ivanovich Tsiferov Method of sinking holes in earth{3 s surface
GB1491687A (en) * 1974-11-29 1977-11-09 Hollandsche Aannemingmaatschap Method and apparatus for underwater dredging of earth particularly sand
US4084648A (en) * 1976-02-12 1978-04-18 Kajima Corporation Process for the high-pressure grouting within the earth and apparatus adapted for carrying out same
US4127950A (en) * 1977-06-02 1978-12-05 Brown & Root, Inc. Bottom jetting device
GB1536591A (en) * 1977-02-17 1978-12-20 Anderson Strathclyde Ltd Nozzle
US4322897A (en) * 1980-09-19 1982-04-06 Brassfield Robert W Airlift type dredging apparatus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR682517A (fr) * 1929-01-19 1930-05-28 Perfectionnements aux procédés d'extraction des sables et autres matériaux dans les bancs noyés
US2413561A (en) * 1945-09-26 1946-12-31 Frederick G Hehr Portable excavating and ejecting machine
FR2096630A1 (fr) * 1970-01-05 1972-02-25 Commissariat Energie Atomique
US3917007A (en) * 1973-06-07 1975-11-04 Mikhail Ivanovich Tsiferov Method of sinking holes in earth{3 s surface
GB1491687A (en) * 1974-11-29 1977-11-09 Hollandsche Aannemingmaatschap Method and apparatus for underwater dredging of earth particularly sand
US4084648A (en) * 1976-02-12 1978-04-18 Kajima Corporation Process for the high-pressure grouting within the earth and apparatus adapted for carrying out same
GB1536591A (en) * 1977-02-17 1978-12-20 Anderson Strathclyde Ltd Nozzle
US4127950A (en) * 1977-06-02 1978-12-05 Brown & Root, Inc. Bottom jetting device
US4322897A (en) * 1980-09-19 1982-04-06 Brassfield Robert W Airlift type dredging apparatus

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0442589A1 (fr) * 1990-01-30 1991-08-21 Rindfleisch, Hans-Joachim, Dr. Procédé et dispositif pour créer des tranchées stables dans la terre et/ou le terrain non consolidé
US4991321A (en) * 1990-06-21 1991-02-12 M-B-W Inc. Pneumatic device for excavating and removing material
GB2245295A (en) * 1990-06-21 1992-01-02 Mbw Inc High velocity pneumatic device
GB2245295B (en) * 1990-06-21 1994-07-06 Mbw Inc High velocity pneumatic device
EP0496481A2 (fr) * 1991-01-25 1992-07-29 The Charles Machine Works Inc Excavateur pour excaver sans dégats
EP0737783A3 (fr) * 1991-01-25 1997-02-12 Charles Machine Works Tige de forage
EP0496481A3 (en) * 1991-01-25 1992-10-07 The Charles Machine Works Inc Soft excavator
US5212891A (en) * 1991-01-25 1993-05-25 The Charles Machine Works, Inc. Soft excavator
EP0737783A2 (fr) * 1991-01-25 1996-10-16 The Charles Machine Works Inc Tige de forage
US5361855A (en) * 1991-01-25 1994-11-08 The Charles Machines Works, Inc. Method and casing for excavating a borehole
GB2252776B (en) * 1991-02-14 1995-04-12 British Gas Plc Formation of a cavity in ground
GB2252776A (en) * 1991-02-14 1992-08-19 British Gas Plc Formation of a cavity in the ground
FR2702515A1 (fr) * 1993-03-11 1994-09-16 Simon Henri Procédé et installation pour réalisation de travaux de terrassements notamment excavation en milieu encombré sensible.
US5966847A (en) * 1996-03-14 1999-10-19 Concept Engineering Group, Inc. Pneumatic excavator
US6158152A (en) * 1996-03-14 2000-12-12 Concept Engineering Group, Inc. Pneumatic excavator
EP1015704A2 (fr) * 1997-03-14 2000-07-05 Concept Engineering Group Inc. Excavatrice pneumatique
EP1015704A4 (fr) * 1997-03-14 2002-06-26 Concept Engineering Group Inc Excavatrice pneumatique
WO2005002735A3 (fr) * 2003-06-30 2006-06-15 John Redding Ameliorations apportees ou se rapportant a des ecoulements liquides tourbillonnaires et a des jets de liquide
CN108824526A (zh) * 2018-05-30 2018-11-16 广东知识城运营服务有限公司 一种基于水利工程用环保清淤装置
CN117071678A (zh) * 2023-09-15 2023-11-17 中交广州航道局有限公司 一种非接触法管道疏浚土处理装置及其处理方法
CN117071678B (zh) * 2023-09-15 2024-04-05 中交广州航道局有限公司 一种非接触法管道疏浚土处理装置及其处理方法

Also Published As

Publication number Publication date
DE3782458T2 (de) 1993-03-18
ATE82027T1 (de) 1992-11-15
DE251660T1 (de) 1990-08-16
ES2035862T3 (es) 1993-05-01
AU6659586A (en) 1987-12-24
FR2600373A1 (fr) 1987-12-24
JPS634130A (ja) 1988-01-09
EP0251660B1 (fr) 1992-11-04
FR2600373B1 (fr) 1989-04-28
DE3782458D1 (de) 1992-12-10
AU593600B2 (en) 1990-02-15

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