Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B44/00—Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
  • E21B44/02—Automatic control of the tool feed
  • E21B44/06—Automatic control of the tool feed in response to the flow or pressure of the motive fluid of the drive

Definitions

• the invention relates to a method for controlling the feeding of a rock drilling machine, wherein the feeding of a drill rod of a rock drilling machine is controlled on the basis of the rotation resistance of the drill rod rotated by a hydraulically operated rotation motor of the machine, so that the rotation resistance is indicated by means of the pressure acting in a pressure fluid conduit of the rotation motor.
• the invention further relates to an arrangement for controlling the feeding of a rock drilling machine, the arrangement comprising a rotation motor for rotating a drill rod and a feed motor for feeding the drill rod in the direction of drilling and back, means for supplying pressure fluid to the feed motor and to the rotation motor, and control means for controlling the supply of the pressure fluid to the feed motor on the basis of the pressure in a pressure conduit of the rotation motor.
• the feeding is switched to a return motion on the basis of the pressure, so that the drill bit would not get stuck in broken rock or the like.
• the problem with the operation of the automation is that the pressure in the conduits of the rotation motor and the feed motor is rather heavily dependent on the flow volume and temperature of the hydraulic fluid. This is due to the fact that the viscosity of the hydraulic fluid and, correspondingly, the pressure losses occurring in the conduits are clearly proportional to the temperature of the hydraulic fluid.
• the purpose of the present invention is to provide a method and an arrangement with which the drawbacks of the known arrangements can be eliminated and rock drilling can be controlled more reliably than previously and the control operations can be made less dependent on the temperature or viscosity of the hydraulic fluid
• the method according to the invention is characterized in that the rotation resistance is determined as the pressure difference acting across the rotation motor, and that the feed motor is controlled on the basis of said pressure difference
• the means for controlling the supply of the pressure fluid to the feed motor comprise means for determining the pressure difference acting across the rotation motor and for controlling the supply of the pressure fluid to the feed motor on the basis of said pressure difference
• the rotation resistance is determined in the form of the pressure difference that acts across the rotation motor, i e the difference between the pressures prevailing in the inlet and outlet conduits of the rotation motor, so that when the pressure difference exceeds a first predetermined threshold value for pressure, which can be set freely, the feeding is controlled on the basis of the aforementioned pressure difference preferably inversely proportionally, such that when the pressure difference exceeds the aforementioned first threshold value and increases further, the supply of pressure fluid to the feed motor is decreased, and if the pressure exceeds a second predetermined threshold value, the feed motor can be switched to the return motion
• the basic idea of the invention is that the rotation resistance is determined in the
• Figure 1 is a schematic hydraulic diagram of an embodiment of the arrangement according to the invention.
• Figure 2 is a schematic hydraulic diagram of another embodiment of the arrangement according to the invention.
• Figure 3 shows schematically a third embodiment of the arrangement according to the invention
• Figure 4 is a schematic electro-hydraulic diagram of a fourth embodiment of the arrangement according to the invention
• Figure 1 is a schematic hydraulic diagram of an embodiment of the arrangement according to the invention
• the figure shows a rotation motor 1 with associated inlet and outlet conduits 2 and 3 for pressure fluid
• the pressure fluid conduits 2 and 3 are generally connected via a rotation control valve 4 to a pressure fluid pump 5 and correspondingly to a pressure fluid container 6
• the figure shows a feed motor 7 of a rock drill, comprising pressure fluid conduits 8 and 9, respectively
• the pressure fluid conduits 8 and 9 are in turn connected via a control valve 10 to a feed control valve 11 and from there to a second pressure fluid pump 12 and to the pressure fluid container 6
• a threshold value for pressure can be set in the control valve 10, normally with a spring 10a the tension of which can be adjusted
• the control valve is pressure-controlled such that when pressure fluid is supplied to the opposite end of the spring and the pressure in that end exceeds the aforementioned threshold value, i e the counterforce of the spring, the valve 10 changes its position and connects the pressure fluid conduits 8 and 9 of the feed motor 7 in a
• FIG. 2 shows an arrangement that is otherwise similar to the one shown in Figure 1 , except that in this arrangement the feed control valve 11 is a pressure-controlled valve and the control valve 10 is connected to guide the control pressure conduits of the feed control valve 1 1 Correspondingly, the feed control valve 1 1 is connected directly to control the pressure fluid conduits 8 and 9 of the feed motor 7 During normal feeding, the control valve 10 is in the situation shown in Figure 2 where the pressure fluid is able to flow through the valve along a first control pressure conduit 15 to the feed control valve 11 , whereupon it is in the position shown in Figure 2 Correspondingly, the pressure fluid can flow from a pressure chamber provided at the other end of the feed control valve 1 1 along a second control pressure conduit 16 through the control valve 10 to the pressure fluid container 6 In Figure 2, the pressure fluid required for the control is provided by a third pressure fluid pump 17 in order to illustrate the matter As the rotation resistance increases, the pressure difference across the feed motor 7 also increases, so that the control valve 10 changes its position and the pressure of the pressure fluid can act on the feed control
• FIG. 3 shows a connection that is otherwise similar to the one shown in Figure 2, expect that it also comprises a separate controlled shut-off valve 18 that reduces the pressure of the pressure fluid arriving from the feed motor when the pressure difference between the pressure conduit and the container conduit of the rotation motor exceeds a predetermined set value.
• the pressure prevailing in the pressure conduit 2 of the rotation motor 1 is connected via a control conduit 19 to the shut-off valve 18 and the container pressure is connected via a conduit 30 to the other side of the valve 18, thus adjusting the limit pressure of the valve so that the higher the pressure rises in the pressure conduit 2, the smaller the set value of the shut-off valve 18.
• the valve 18 is in turn connected to the feed control valve 11 by means of a regulating conduit 20, so that when the feeding takes place in the normal feed direction, the regulating conduit 20 is connected to the inlet pressure conduit of the feed motor, i.e. to the pressure fluid conduit 8, the pressure of which is adjusted according to the valve 18.
• FIG 4 shows schematically a fourth embodiment of the arrangement according to the invention the operation of which may correspond to the operation of the hydraulic connection shown in either Figure 2 or Figure 3.
• the pressure difference across the rotation motor 1 is measured electrically, i.e. with either one pressure difference sensor or two pressure sensors 21a and 21b.
• the connection comprises a control unit 22 that stores the measured pressure difference and then controls, by means of signal channels 23a and 23b, a feed control valve 11', which in this case is an electrically controlled feed control valve.
• control unit 22 may switch to the return motion of the feed motor only when the pressure difference exceeds the predetermined pressure limit, or the unit can be connected to adjust the pressure of the pressure fluid supplied to the feed motor inversely proportionally to the pressure difference until it switches the feeding to the return motion when the pressure difference exceeds the second predetermined threshold value.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Fluid-Pressure Circuits (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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ID=8546277

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Cited By (9)

Citations (4)

• 1996
  • 1996-06-25 FI FI962622A patent/FI105943B/fi active
• 1997
  • 1997-06-12 ZA ZA9705194A patent/ZA975194B/xx unknown
  • 1997-06-18 AU AU31782/97A patent/AU3178297A/en not_active Abandoned
  • 1997-06-18 WO PCT/FI1997/000392 patent/WO1997049895A1/en active Application Filing

Patent Citations (4)

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