EP0703345A2 - Boring ram - Google Patents

Abstract

In a ram boring device, with an essentially cylindrical hull (10), a head (32) in which at least one nozzle opening (14) is formed for the discharge of a high pressure liquid jet, and an impact mechanism which is arranged in the hull (10) and can be driven by a pressure medium (20) for propelling the ram boring device, the striking mechanism (20) is designed as a hydraulic striking mechanism, the striking mechanism (20) and the nozzle opening (14) being connectable to the same pressure fluid source. <IMAGE>

Description

The invention relates to a ram boring device with an essentially cylindrical fuselage, a head in which at least one nozzle opening is formed for the exit of a high-pressure liquid jet, and an impact mechanism arranged in the fuselage and driven by a pressure medium for propelling the ram boring device.

Such a ram boring device is known, for example, from US Pat. No. 4,858,703. In the device described there, the striking mechanism is driven by compressed air. The liquid required for the high-pressure liquid jet is fed via a line into an expansion chamber in the housing and is expelled from this expansion chamber by means of compressed air.

Furthermore, solutions are known in the prior art in which the percussion mechanism is driven by compressed air, while separate from this high-pressure liquid is supplied to the nozzles.

All known solutions have the disadvantage that two types of pressure medium have to be supplied. Thereby at least two pressure medium sources are required and the structure of the ram boring device is correspondingly complicated. In addition, several pressure medium lines must be provided, which are often a source of malfunctions in practical operation. If the pressure is high, these lines have to be designed with correspondingly thick walls and are therefore inflexible, heavy and impeding practical operation.

The invention has for its object to provide a ram boring device of the type mentioned, which is simpler and cheaper in construction and easier to handle.

This object is achieved in that the striking mechanism is designed as a hydraulic striking mechanism and that the striking mechanism and the nozzle opening can be connected to the same hydraulic fluid source.

For the ram boring device according to the invention, therefore, only one pressure medium source is required, which for example supplies water, a water-polymer mixture or bentonite to the ram boring device under high pressure. Thus, a single pressure medium supply line to the ram boring device is sufficient. The ram boring device can be constructed correspondingly more simply and is easier to handle, since it only has to be connected to the stationary station via a single pressure medium hose.

If the fuselage is connected to a propulsion linkage, a control valve for selectively supplying the pressure fluid to the impact mechanism and / or to the nozzle opening can be arranged in the fuselage in the hydraulic fluid line upstream of the striking mechanism and / or the nozzle opening. This offers the possibility, depending on the nature of the soil in which the ram boring device is used, of the ram boring device with or without the use of the striking mechanism advance. For example, the control valve can be designed so that it can be controlled depending on the pressure level of the hydraulic fluid. For example, the arrangement can be such that the hammer mechanism does not work at flushing pressures of up to 80-100 bar, but rather the flushing liquid only emerges in a known manner from the front or the flushing nozzles of the drill head in order to loosen the soil. If the operator sets the flushing pressure to a value above 80-100 bar, the control valve opens the supply to the striking mechanism so that it begins to work. As a result, the ram boring device actively drives through the soil even in gravelly soils. While the striking mechanism is working, flushing liquid for loosening the soil emerges at the front of the drill head in a known manner.

The head, together with the fuselage, can preferably be rotated about its longitudinal axis by means of the propulsion linkage and has a control surface directed at a different angle from the longitudinal axis of the fuselage. To improve the drilling result, at least the control surface can be equipped with hard metal bodies. For straight-line drilling, the ram boring device is rotated at, for example, 100 to 200 revolutions per minute. To control the ram boring device and change the direction of the bore, the ram boring device is stopped in a certain position of the head and the boring device is then moved forward without striking or statically, being deflected in the desired direction by the control surface on the head. This process is supported by the liquid that emerges from the orifice orifices.

The head can also be symmetrical with respect to the longitudinal axis of the fuselage. Such a head can smash obstacles better than the asymmetrical head with control surface. However, its steering characteristics are less good than the asymmetrical head, since the control effect can only be achieved by an asymmetrical arrangement of the nozzle openings.

The head can be axially rigid or movably connected to the body. The head is expediently connected to the fuselage so that different shapes of the head can be used in accordance with the respective floor.

To locate the ram boring device in the ground, the ram boring device can contain, in a manner known per se, a transmitter for emitting electromagnetic radiation, with the aid of which the position of the boring device can be determined and via which measurement data can also be transmitted from the ram boring device to the surface. The transmitter is expediently arranged in a shock-absorbing manner in relation to the direction of advance behind the striking mechanism, in order to better protect it against damage.

For manufacturing and maintenance reasons, the fuselage can be divided into a part containing the striking mechanism and a part receiving the transmitter.

In a preferred embodiment of the invention, the outer diameter of the ram boring device decreases from front to back. On the one hand, this facilitates the control of the device and, on the other hand, the discharge of the drilled or displaced material through the flushing liquid to the rear. The outer diameter of the fuselage section receiving the striking mechanism is expediently smaller than the outer diameter of the head and the outer diameter of the fuselage section receiving the transmitter is smaller than the outer diameter of the fuselage section receiving the striking mechanism.

In order to be able to use water as the hydraulic fluid without the risk of corrosion, it is expedient if at least the parts of the ram boring device which come into contact with the hydraulic fluid are made of a corrosion-resistant material, in particular stainless steel.

Figur 1

eine schematische Darstellung einer Bohreinrichtung unter Verwendung der erfindungsgemäßen Rammbohrvorrichtung,

Figur 2

einen schematischen Längsschnitt durch eine erste Ausführungsform einer erfindungsgemäßen Rammbohrvorrichtung mit symmetrischem Kopf,

Figur 3

einen schematischen Längsschnitt durch eine zweite Ausführungsform der erfindungsgemäßen Rammbohrvorrichtung mit asymmetrischen Kopf,

Figur 4

einen der Figur 3 entsprechenden Teilschnitt durch die Rammbohrvorrichtung mit einer teilweisen schematischen Darstellung des Schlagwerkes mit dem Schlagkolben in seiner vorderen Position und

Figur 5

einen der Figur 4 entsprechenden Schnitt mit dem Schlagkolben in seiner hinteren Position.

Further features and advantages of the invention will become apparent from the following description, which explains the invention with reference to exemplary embodiments in conjunction with the accompanying drawings. Show it:

Figure 1

1 shows a schematic illustration of a drilling device using the ram boring device according to the invention,

Figure 2

2 shows a schematic longitudinal section through a first embodiment of a ram boring device according to the invention with a symmetrical head,

Figure 3

2 shows a schematic longitudinal section through a second embodiment of the ram boring device according to the invention with an asymmetrical head,

Figure 4

a partial section corresponding to Figure 3 through the ram boring device with a partially schematic representation of the striking mechanism with the percussion piston in its forward position and

Figure 5

a section corresponding to Figure 4 with the percussion piston in its rear position.

FIG. 1 shows a drill carriage 2 with a ramp 4 for driving, rotating and controlling a ram drilling device 6 by means of a drill pipe 8. The drill carriage contains a source of hydraulic fluid, not shown.

The ram boring device 6 shown in FIG. 2 comprises a cylindrical fuselage 10, at the front end of which a boring head 12 is arranged which is symmetrical with respect to the longitudinal axis of the fuselage. This has at least one nozzle opening 14 which is connected via a channel 16 and a control valve 24 to a pressure medium connection 18 at the rear end of the fuselage or housing 10.

Within the housing 10 there is also a striking mechanism 20 which is only indicated schematically and which, together with the head 12, can automatically propel the fuselage 10 through floors of a certain nature. The striking mechanism 20 is also connected to the pressure medium connection 18 via a line 22 and the control valve 24. The control valve 24 can be controlled in a pressure-dependent manner in such a way that either only the nozzle opening 14 or the nozzle opening 14 and the striking mechanism 20 are connected to the pressure fluid source.

At its rear end, the housing 10 is connected to the hollow jacking or drilling rod 8, via which the ram boring device can be statically driven and rotated from the drilling carriage 2.

A pressure fluid, for example water, a water-polymer mixture or another known drilling fluid, is supplied via the pressure medium connection 18 and a pressure fluid line 26 connected to it and guided within the hollow drill pipe 8. If the pressure is below a predetermined threshold value, for example 80 to 100 bar, the control valve 24 blocks the line 22. Pressure fluid thus emerges from the nozzle openings 14 in order to loosen up or flush away the soil in front of the head 12.

Is the condition of the soil such that the static propulsion of the ram boring device via the propulsion linkage 8 is no longer possible, the pressure of the pressure fluid is increased above the threshold value, so that the control valve 24 opens and the pressure fluid drives the striking mechanism 20. This means that the ram boring device can also be driven through gravelly or stony soils or smash individual obstacles.

The threshold value at which the control valve 24 blocks the line 22 again and thus interrupts the operation of the striking mechanism 20 should be significantly below the threshold value for switching on the striking mechanism 20 in order to prevent the control valve from fluttering. The moment the hammer mechanism is switched on, the fluid pressure drops suddenly due to the increased fluid requirement. If the two threshold values for activating or deactivating the striking mechanism did not differ, or differed only slightly from one another, permanent activation and deactivation of the striking mechanism could not be avoided.

The directional control of the ram boring device according to FIG. 2 takes place in such a way that the ram boring device is held in a certain rotational position, so that the asymmetrically arranged nozzles on the side of the ram boring device soften the ground, after which the ram boring device is to be deflected. If the ram boring device is then driven forward using the drill pipe or the impact device, it is deflected into the deviated ground area. The ram boring device can then be rotated again by means of the drill pipe for straight running.

In the embodiment shown in FIG. 3, the fuselage 10 comprises a first section 30, in which the striking mechanism 20 and the control valve 24 are arranged. At the front end of the fuselage section 30 is a asymmetrical control head 32 arranged interchangeably. The control head 32 has a control surface 36 which is directed obliquely to the fuselage axis 34 and is equipped with hard metal bodies 38. The control head 32 and fuselage 10 can be rotated about the fuselage axis 34 by means of the drill pipe 8 or held in a desired position relative to the fuselage 10. The control head 34 also has a nozzle opening 14 which opens towards the side in such a way that the emerging nozzle jet is directed obliquely forward away from the fuselage axis 34.

At the connection point between the fuselage section 30 and the control head 12, a coupling 28 is provided for the connection of the sections of the liquid line 16, which enables an axial movement of the control head 12 relative to the fuselage 10, as will be explained with reference to FIGS. 4 and 5.

A transmitter housing 40 adjoins the rear end of the fuselage section 30, in which a transmitter 42 is mounted in a shock-absorbing manner. The transmitter 42 emits electromagnetic radiation through slots 44 provided in the transmitter housing 40, with the aid of which the position of the ram boring device can be determined via suitable receivers on the earth's surface. The transmitter 42 also serves to determine the position of the control surface 36 in space so that the ram boring device can be effectively controlled.

At the rear end of the fuselage section forming the transmitter housing 40 there is a connecting piece 46 for the hollow push rod 8, through which the hydraulic fluid is supplied.

As can be seen, the outer diameter of the cylindrical fuselage section 30 is somewhat smaller than the outer diameter of the control head 32. The outer diameter of the transmitter housing 40 in turn is somewhat smaller than the outer diameter of the fuselage section 30.

The striking mechanism will now be explained in more detail with reference to FIGS. 4 and 5. The figures show the control head 12 and the fuselage section 30 of the embodiment shown in FIG. 3. The same parts are provided with the same reference numerals. The fuselage section 30 consists of three housing parts 48, 50, 52. The housing sections 50 and 52 are screwed together at 54. The two sections 50 and 48 are put together and secured by bolts 56. The control head 32 is inserted into the front end of the housing section 48 with a pin 58. The pin 58 has on its circumferential surface a groove 60 into which a bolt 62 penetrating the housing section 48 engages. As can be seen from FIGS. 4 and 5, the control head 32 is thereby held on the housing section 48 so that it cannot rotate but is axially movable.

A percussion piston 66 is axially displaceably mounted in an axial bore, generally designated 64, in the fuselage section 30. It comprises a larger-diameter front shaft 68 and a smaller-diameter rear shaft 70. A first front piston section 72 defines with front seals 74 in the axial direction a front chamber 76 of bore 64. A rear second piston section 78 delimits an axial distance from first piston section 72 A central chamber 80 of the bore 64 in the axial direction together with the first piston section 72. The rear piston section 78, together with rear seals 82, delimits a rear chamber 84 of the bore 64 in the axial direction.

The pressure line 22 for supplying the hydraulic fluid to the striking mechanism 20 connects the control valve 24 to an inlet opening 86 in the front chamber and an inlet opening 88 in the rear chamber. The rear chamber and the middle chamber are connected by a control line 90. The middle chamber 80 is also connected via an outlet opening 92 to an outlet 94 for the pressure fluid. The outlet 94 is also connected via a line 96 to an outlet opening 98 in the rear chamber 84.

The rear shaft 70 is surrounded at a radial distance by a control sleeve 100, which has a plurality of radial bores 102.

FIG. 4 shows the percussion piston in its foremost position, in which it strikes the pin 58 of the control head 32, the axial movement of this control head not being taken into account in the drawing. The axial mobility of the control head 32 enables a better utilization of the kinetic energy of the percussion piston 66. In this position, the control sleeve 100 is also in its front end position. The middle chamber 80 is connected to the outlet 94. The inflow of pressure fluid through the inlet opening 88 is blocked by the control sleeve 100. In contrast, the inlet opening 86 in the first chamber is only partially blocked by the front piston section 72, so that pressure fluid can act on the annular surface 104 of the piston section 72 facing forward. Since the middle chamber 80 and the rear chamber 84 are connected to the unpressurized outlet 94 and the inlet opening 88 for the pressure fluid in the rear chamber 84 is blocked by the control sleeve 100, the percussion piston 66 is moved from the position shown in the figure to the left, ie moved backwards. As soon as the piston section 72 has passed the outlet opening 92 of the middle chamber 80, pressure fluid can no longer escape from the middle chamber. The dimensioning of the pressure-effective areas on the control sleeve 100 is selected such that the latter is likewise moved to the right or to the rear in FIG. 4 until it comes on strikes a shoulder 106 of the housing portion 52. In this position, the inlet opening 88 is opened for the admission of pressure fluid to the rear chamber 84. This position of the striking mechanism is shown in FIG. 5. The pressure of the inflowing hydraulic fluid acts on the rearward-facing annular surface 108 of the piston section 78, which is larger than the annular surface 104 of the piston section 72. As a result, the percussion piston 66 is not only braked but moved again to the left, ie forwards, from the end position shown in FIG. 5 until it hits the pin 58 of the control head 32. The piston section 72 exposes the outlet opening 92 at the central chamber 80 so that the pressure can drop therein. The pressure drop in the middle chamber 80 via the control line 90 causes the pressure in the rear chamber 84 to move the control sleeve 100 to the left, ie forward, until it has reached the position shown in FIG. 4, in which the inlet opening 88 for the hydraulic fluid to the rear chamber 84 is closed again. The cycle described begins again.

The device described so far according to FIGS. 3 to 5 works as follows:

The pressure of the flushing liquid can be continuously adjusted from the drilling vehicle 2 arranged on the surface of the earth or in a starting pit. At a flushing pressure of up to approx. 100 bar, the control valve 24 remains closed, so that the striking mechanism 20 does not work. In this case the device only works as a drilling device. In order to drill straight ahead, the ram boring device, ie head 32 and fuselage 10, is rotated at approximately 100 to 200 revolutions per minute and at the same time is pushed forward via the linkage 8, not shown. The flushing liquid, which emerges from nozzles facing forwards or to the side, loosens the soil and thus facilitates the drilling process. In Special soils, such as sandy soils, require the soil to be discharged backwards along the rod. This is done by the escaping rinsing liquid. A polymer / water mixture or bentonite is expediently used for this purpose. In order to control the drilling device and thus to change the direction of the drilling, the drilling head is brought into a suitable rotational position, wherein this information about the current rotational position can also be determined via the transmitter 42. The drilling device is then pressed forward when the drilling head 32 is not rotating. The control surface 36 directed obliquely to the fuselage axis 34 causes the drilling device to be deflected in the desired direction. This process is also supported by the rinsing liquid that emerges from the nozzles 14. This is particularly the case if the nozzles are attached laterally, since the soil can then be loosened in the direction in which the drilling device is to be deflected.

With densely stored gravel or stony ground, the procedure described above is no longer possible. In such a soil, the drilling device can only be driven by means of the striking mechanism 20. To switch on the striking mechanism, the flushing pressure is set to 150 to 200 bar, for example. Since the control valve 24 opens from a flushing pressure of approximately 100 bar, the striking mechanism 20 now begins to strike. The rinsing liquid now flows both through the channel 16 to the nozzle or nozzles 14 and via the line 22 to the striking mechanism 20 in order to drive it. The flushing liquid emerges from the striking mechanism 20 almost without pressure laterally through the bore 94 in the fuselage section 30. This is facilitated by the somewhat smaller outer diameter of the fuselage section 30. The emerging drilling fluid takes along drilled material. By reducing the diameter of the fuselage sections 30 and 40 relative to the head 32, the controllability of the ram boring device is also increased. The Striking mechanism 20 thus supports the driving of the ram boring device when driving straight ahead and when cornering in gravel and stony soils, in which the purely static propulsion supported by the flushing jets is no longer sufficient.

Claims (16)

A ram boring device, having an essentially cylindrical hull (10), a head (12, 32) in which at least one nozzle opening (14) is formed for the discharge of a high pressure liquid jet, and an impact mechanism which is arranged in the hull (10) and can be driven by a pressure medium (20) for propelling the ram boring device, characterized in that the striking mechanism (20) is designed as a hydraulic striking mechanism and that the striking mechanism (20) and the nozzle opening (14) can be connected to the same hydraulic fluid source. A ram boring device according to claim 1, characterized in that the fuselage (10) is connected to a propulsion linkage (8) and that in the fuselage (10) in the hydraulic fluid line (22) upstream of the striking mechanism (20) and / or the nozzle opening (14) a control valve (24) for selectively supplying the pressure fluid to the striking mechanism (20) and / or to the nozzle opening (14) is arranged. A ram boring device according to claim 2, characterized in that the control valve (24) can be controlled as a function of the liquid pressure. A ram boring device according to one of claims 1 to 3, characterized in that the head (12, 32) together with the fuselage (10) is rotatably mounted about its longitudinal axis (34) by means of the linkage (8). A ram boring device according to claim 4, characterized in that the head (12) is designed symmetrically with respect to the longitudinal axis of the fuselage (34), with more than one nozzle opening (14) this are arranged asymmetrically with respect to the fuselage longitudinal axis (34). A ram boring device according to claim 4, characterized in that the head (32) has a control surface (36) directed at an angle different from 90 ° to the fuselage axis (34). A ram boring device according to claim 6, characterized in that at least the control surface is equipped with hard metal bodies (38). A ram boring device according to one of claims 5 to 7, characterized in that the head (12, 32) is axially rigidly connected to the fuselage (10). A ram boring device according to one of claims 5 to 7, characterized in that the head (12, 32) is axially movably connected to the fuselage (10). A ram boring device according to one of claims 1 to 9, characterized in that the head (12, 32) is connected to the fuselage (10) in an exchangeable manner. A ram boring device according to one of claims 1 to 10, characterized in that it contains a transmitter (42) for emitting electromagnetic radiation, with the aid of which the position of the boring device can be determined. A ram boring device according to claim 11, characterized in that the transmitter (42) is arranged in a shock-absorbing manner in a transmitter housing (40) lying behind the striking mechanism (20) in relation to the direction of advance. A ram boring device according to one of claims 1 to 12, characterized in that the fuselage (10) is divided into a part (30) containing the striking mechanism (20) and a part (40) receiving the transmitter (42). A ram boring device according to one of claims 1 to 13, characterized in that its outer diameter decreases from the front to the rear. A ram boring device according to claim 14, characterized in that the outside diameter of the fuselage section (30) receiving the striking mechanism (20) is smaller than the outside diameter of the head (32) and the outside diameter of the fuselage section (40) receiving the transmitter (42) is smaller than the outside diameter of the the fuselage (20) receiving fuselage section (30). A ram boring device according to one of claims 1 to 15, characterized in that at least the parts of the ram boring device which come into contact with the hydraulic fluid are made of corrosion-resistant material, in particular stainless steel.

Images