WO2019175765A1

WO2019175765A1 - Drilling machine

Info

Publication number: WO2019175765A1
Application number: PCT/IB2019/051993
Authority: WO
Inventors: Andrea Vaccari
Original assignee: Graf S.P.A.
Priority date: 2018-03-13
Filing date: 2019-03-12
Publication date: 2019-09-19
Also published as: EP3765702A1; IT201800003515A1

Abstract

The drilling machine (1) comprises: - a machine body (2); - a drilling head (3) associated in a movable manner with the machine body (2) which is adapted to excavate in a ground (4) along a direction of drilling (A) provided with a substantially vertical component to make a hole (5); and - an extruding assembly (6) associated with the machine body (2) and adapted to extrude a polymeric material (16) to produce a piping (7) extending into the hole (5) along the direction of drilling (A) and which is adapted to make a geothermal probe.

Description

DRILLING MACHINE

Technical Field

The present invention relates to a drilling machine.

Background Art

The use of drilling machines is well known for the construction of geothermal systems and probes.

In particular, geothermal probes are systems used in both the civil and industrial field, which allow exploiting geothermal energy for various uses, such as e.g. air conditioning of rooms.

In recent years, the use of geothermal probes has increased as these allow reducing the use of conventional electricity and CO₂ emissions while ensuring the heating of rooms in winter and air conditioning in summer as well as the supply of domestic hot water.

These systems require the use of a heat transfer fluid which is adapted to exchange heat with the ground, which is made to flow in pipes housed in special vertical holes dug into the ground.

Therefore, the drilling machines are intended to make these holes in the ground, in which U-shaped pipes are inserted, so as to allow the delivery and return of the heat transfer fluid.

The vertical holes for the geothermal probes are typically as deep as a few hundred meters and have a small diameter, generally less than one meter, so that the drilling machines used have rather small dimensions.

Once the pipes have been laid down, a specific pre-mixed bentonite cements product is injected into the hole, in order to saturate the spaces and create the best conductivity between the fluid circulating in the probes and the surrounding ground and to prevent communication between any water-bearing layers crossed by the drilling.

In many cases, known drilling machines are made by means of several blocks connected together by means of joints, so as to allow these to return to the surface once they have reached the desired depth, through the construction of an auxiliary ascending duct. These drilling machines do, however, have a number of drawbacks.

In fact, the construction of geothermal probes by means of known drilling machines is a very long and expensive process, as it involves the making of the hole and the subsequent laying down of pipes, which greatly increases the costs of construction.

In addition, these machines are rather complex because they are composed of several parts, so they are more subjected to failures and malfunctions, with a corresponding increase in the operating and maintenance costs.

Description of the Invention

The main aim of the present invention is to devise a drilling machine that allows reducing both times and, consequently, costs for the construction of a geothermal probe.

Within the illustrated aim, one object of the present invention is to allow the construction of a drilling machine having a simpler structure and operation than the machines of known type.

Another object of the present invention is to devise a drilling machine that allows overcoming the aforementioned drawbacks of the prior art in a simple, rational, easy, effective to use and low-cost solution.

The aforementioned objects are achieved by the present drilling machine according to claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will be more evident from the description of a preferred, but not exclusive, embodiment of a drilling machine, illustrated by way of an indicative, but non-limiting example, in the attached tables of drawings in which:

Figure 1 is a schematic sectional view of the machine according to the invention;

Figure 2 is a schematic sectional view of the operation of the machine according to the invention.

Embodiments of the Invention

With particular reference to these illustrations, reference numeral 1 globally indicates a drilling machine.

According to the invention, the drilling machine 1 comprises:

at least one machine body 2;

at least one drilling head 3 associated in a movable manner with the machine body 2 which is adapted to excavate in a ground 4 along at least one direction of drilling A provided with at least one substantially vertical component to make at least one hole 5; and

at least one extruding assembly 6 associated with the machine body 2 and adapted to extrude at least one polymeric material 16 to produce at least one piping 7 extending into the hole 5 along the direction of drilling A and which is adapted to make at least one geothermal probe.

The geothermal probe, also called the receiver probe, is a heat exchange system with the ground through which geothermal energy is taken, which is used e.g. for the air conditioning of rooms.

This is a closed circuit consisting of pipes that exchange heat with the ground by means of the circulation of a heat transfer fluid.

Since the direction of drilling A has a vertical component, it follows that the hole 5 evolves substantially vertically so as to go deep into the ground 4, so that the geothermal probe obtained is of the type commonly known as“vertical probe”.

At a certain depth, in fact, the ground has a substantially constant temperature of about 15 °C, which is not affected by the temperature at the outer surface 28.

In particular, the invention allows making an extremely deep hole 5, even with a depth of several hundred meters, where the ground 4 has a rather high temperature.

The temperature of the ground 4, in fact, increases as the depth increases and, at the level reached by the machine 1, the temperature is about 90°C, so the geothermal probe made this way is particularly useful for the receipt of heat.

This characteristic is exploited in order to exchange heat with the heat transfer fluid, which in winter is heated inside the geothermal probe, while in summer it is cooled down. The fluid is then conveyed to a heat exchange system which, through a compressor or an expander, allows the air to be heated or cooled and, therefore, to provide for the air conditioning of the rooms.

Usefully, the hole 5 extends for several hundred meters, so as to have a heat exchange that is not affected by the temperature of the external environment. Preferably, the drilling head 3 is provided with erosion means that allow eroding the ground 4 surrounding the drilling head itself, in order to make the hole 5.

The machine 1 comprises motorized means 8 operatively connected to the drilling head 3 and adapted to move the drilling head itself according to at least one of:

a rotary mode in which the drilling head 3 rotates around an axis of drilling B substantially parallel to the direction of drilling A; and

a sussultatory mode in which the drilling head 3 translates with an alternated motion parallel to the direction of drilling A.

Preferably, as shown in the figure, the axis of drilling B is substantially the same as the direction of drilling A.

In particular, the rotary movement of the drilling head 3 allows crumbling the surrounding ground 4, so as to open a space for making the hole 5.

In some cases, however, the ground 4 can be particularly hard and compact depending on its composition, so it is useful to use the sussultatory type movement of the drilling head 3 which, beating on the bottom of the hole 5, facilitates the erosion of the ground itself.

The machine 1 usefully comprises gripping means 9 associated with the machine body 2 and adapted to enter in contact with a wall 10 of the hole 5 during the movement of the drilling head 3.

These gripping means 9 allow the machine body 2 to be fixed to the wall 10, thus preventing this from being driven in rotation by the movement of the drilling head 3.

In addition, the gripping means 9 may allow the movement of the machine 1 along the hole 5 in order to allow the forward movement of the machine at the same time of the excavation. The gripping means 9 also allow managing the direction of drilling A, in order to make a hole 5 both vertical and helical, as schematically shown in Figure 2 as an example, so as to maintain vertical the component.

In fact, during the drilling operation, the gripping means 9 enter in contact with the wall 10, and by means of appropriate thrusts and movements they carry out an action of directing the drilling head 3, with the possibility of obtaining the hole 5 both vertical and helical, although the possibility of making the hole 5 with a different conformation from the examples shown cannot be ruled out. Furthermore, the possibility cannot be ruled out of providing means other than the gripping means 9 in order to manage the variation in the direction of drilling A.

In particular, the fact of making the hole 5 with a substantially helical shape makes it possible to obtain a condition of greater stability than the hole itself with vertical conformation, since it makes it possible to avoid any structural failure of the wall 10 of the hole 5 during the passage of the machine 1, which is particularly useful especially in the case of a crumbly ground 4.

In addition, obtaining a hole 5 is particularly useful in the case wherein the hole itself is placed between a first layer 29 and a second layer 30, so there is no risk of the two layers being put in communication, even in the case of structural failures.

Preferably, the gripping means 9 are of the type selected from the list comprising: tracks, harpoons, jacks, cams and the like, although the possibility of providing gripping means 9 of a different type cannot be ruled out.

Advantageously, the presence of the extruding assembly 6 allows the construction of the piping 7 of the geothermal probe during the drilling itself, so as to avoid further steps of laying down the piping itself.

In addition, the fact of providing the extruding assembly 6 allows speeding up the operations for the construction of the geothermal probe, also reducing its costs.

The typically used polymeric material 16 is preferably polyethylene, which allows for a high strength piping, although the possibility cannot be ruled out of using a different polymeric material 16.

In the preferred embodiment, the extruding assembly 6 comprises at least one shaped extrusion section to define the piping 7 with a plurality of pipes extending into the hole 5 along the direction of drilling A.

In practice, the extruding assembly 6 is equipped with a melting chamber inside which the polymeric material 16 is brought to the molten state, so that it can then be extruded through the shaped section.

In particular, the pipes comprise:

at least one delivery pipe 11 which is adapted to deliver at least one of water for supplying the geothermal probe and at least one cooling fluid 12 for cooling the drilling head 3;

at least one return pipe 13 which is adapted to return to surface of at least one of water for supplying the geothermal probe and the cooling fluid 12 together with drilling debris 14;

at least a first supply pipe 15 which is adapted to supply the extruding assembly 6 by means of the polymeric material 16 in a thread-like form; and at least a second supply pipe 17 which is adapted to allow the passage of cables 18 for the power supply of the motorized means 8.

Preferably, the cooling fluid 12 is water, although the possibility of using a different cooling fluid 12 cannot be ruled out.

In addition, during drilling operations the temperature of the drilling head 3 increases significantly due to both the heat produced by the motorized means and the friction that develops between the drilling head itself and the ground 4. As a result, the fact of conveying the cooling fluid 12 through the delivery pipe 11 allows maintaining the temperature of the drilling head 3 within a range of values that allow it to operate properly without the risk of failure.

Advantageously, the machine body 2 comprises at least one cavity 19 in which the extruding assembly 6 is housed and defining at least one outlet duct 20 of the piping 7.

Immediately after extrusion, the piping 7 has high temperatures, therefore it is not perfectly solidified yet and any contact with the wall 10 of the hole 5 or with the drilling debris 14 could cause deformation and impair its proper operation. As a result, the outlet duct 20 allows protecting the piping 7 just outside the extrusion section, so as to allow a proper cooling thereof and make sure it has adequate mechanical strength.

Usefully, the machine 1 comprises conveying means 21 adapted to convey the drilling debris 14 into at least one of the return pipe 13 and the space 22 comprised between the pipes 11, 13, 15, 17 and the hole 5.

The drilling debris 14 are used in fact to fill the hole 5, so as to saturate the spaces and prevent the formation of air chambers inside the hole itself.

In particular, this measure allows maximizing heat conductivity, and therefore maximizing the efficiency of the heat exchange between the water circulating inside the geothermal probe and the surrounding ground, as well as preventing communication between any water-bearing layers crossed by the drilling operation.

The volume occupied by the drilling debris 14 is however greater than the volume of the corresponding initial compact ground 4, so it is not possible to use the entire mass of debris for filling the space 22.

As a result, one part of the drilling debris 14 is mixed with the water used as cooling fluid 12 and conveyed out of the hole 5 through the return pipe 13, by means of lifting equipment integrated in the machine 1 that allows it to be moved.

The remaining part of this mixture is conveyed inside the space 22 by means of a special outlet duct 24.

The cooling fluid 12 is preferably conveyed to the outside of the machine 1 through the gap which is formed between the drilling head 3 and the wall of the hole 5, so as to mix with the drilling debris 14.

This mixture is collected by the conveying means 21 through at least one collection opening 23 and then distributed.

It is also possible to mix the drilling debris 14 to be conveyed inside the hole 5 with at least one binding substance, such as e.g. cement, glue, polymer foams, metal foams or other sealing compounds, thus making a compact filler. In this way, it is possible to waterproof the drilling debris 14, thus avoiding the infiltration of water through the hole 5 and any communication with the water bearing layers.

This binding substance can be supplied to the machine 1 through one of the pipes 11, 13, 15, 17, or a dedicated pipe can be provided similar to those already provided.

Advantageously, the machine 1 comprises detection and control means 25, 27 which are adapted to manage the forward movement of the machine 1 along the direction of drilling A.

In particular, the detection and control means 25, 27 can be intended for various purposes, such as e.g. the detection of the composition of the ground 4 surrounding the machine 1, the measure of the drilling depth, the detection of the presence of obstacles, such as e.g. pipelines, and the calibration of the direction of drilling A, until the established depth has been reached.

In the preferred embodiment shown in the figures, the detection and control means 25, 27 comprise at least one detection unit 25 housed on the machine 1 and at least one control unit 27 located at one outer surface 28 which is operatively connected to the detection unit itself by means of the connecting means 31.

In particular, the detection unit 25 is provided with sensors which are adapted to detect, for example, the position of the machine 1 and the configuration of the surrounding ground 4 and through the connecting means 31 the unit provides the data to the control unit 27.

This control unit 27 is arranged on the outer surface 28 so as to be easily usable by the operators, for the management of the forward movement and the direction of the machine 1.

Preferably, the connecting means 31 comprise at least one cable which is adapted to connect the detection unit 25 and the control unit 27 to each other and which is made to pass through the second supply pipe 17 together with the cables 18, although the use of connecting means of the wireless type cannot be ruled out. Once the predetermined depth has been reached, the drilling head 3 stops and, since it is not provided with means that allow the same to rise towards the outside, remains at the bottom of the hole 5, which means that this machine is “disposable” and cannot be recovered.

In addition, the machine 1 is provided with cutting means that allow cutting the piping 7, separating it from the extrusion section to define one end for each of the pipes 11, 13, 15, 17.

The machine 1 advantageously comprises connecting means of the geothermal probe which are adapted to connect the delivery pipe 11 and the return pipe 13 to each other by means of at least one connecting component 26 which is pre- loaded on the machine body 2.

In this way it is possible to close the circuit and allow the water for the supply of the geothermal probe to circulate between the delivery pipe 11 and the return pipe 13 and exchange heat.

Preferably, the connecting component 26 is substantially U-shaped, although the possibility of providing the connecting component 26 with a substantially coil shape cannot be ruled out, so as to increase the heat exchange surface and consequently increase the efficiency of the heat exchange itself.

Furthermore, the possibility of providing the connecting component 26 provided with a finned surface cannot be ruled out, in order to further increase the exchange surface, thereby increasing the efficiency of the heat exchange.

Preferably, the connecting component 26 is provided with assembly means which are adapted to allow assembling the same by interlocking at the ends of the pipes 11, 13, although the possibility of providing assembly means of a different type cannot be ruled out, such as e.g. gluing or sealing means.

It has in practice been ascertained that the described invention achieves the intended objects.

In this regard, it should be noticed that the special measure of providing a drilling machine provided with a drilling head and with an extruding assembly allows constructing a geothermal probe in a single step, with a significant reduction in manufacturing times and costs. In addition, the special measure of assembling the drilling head and the extruding assembly makes it possible to obtain a drilling machine having a simpler structure and operation than the machines of known type.

Furthermore, the special measure of providing gripping means which allow managing the direction of the drilling head allows making not only vertical, but also helical holes, thus avoiding any structural failure inside the hole itself during drilling.

Claims

1) Drilling machine (1), characterized by the fact that it comprises:

at least one machine body (2);

at least one drilling head (3) associated in a movable manner with said machine body (2) which is adapted to excavate in a ground (4) along at least one direction of drilling (A) provided with at least one substantially vertical component to make at least one hole (5); and

at least one extruding assembly (6) associated with said machine body (2) and adapted to extrude at least one polymeric material (16) to produce at least one piping (7) extending into said hole (5) along said direction of drilling (A) and which is adapted to make at least one geothermal probe.

2) Machine (1) according to claim 1, characterized by the fact that it comprises motorized means (8) operatively connected to said drilling head (3) and adapted to move said drilling head (3) according to at least one of:

a rotary mode in which said drilling head (3) rotates around an axis of drilling (B) substantially parallel to said direction of drilling (A); and a sussultatory mode in which said drilling head (3) translates with an alternated motion parallel to said direction of drilling (A).

3) Machine (1) according to one or more of the preceding claims, characterized by the fact that said extruding assembly (6) comprises at least one shaped extrusion section to define said piping (7) with a plurality of pipes extending into said hole (5) along said direction of drilling (A).

4) Machine (1) according to one or more of the preceding claims, characterized by the fact that said pipes comprise:

at least one delivery pipe (11) which is adapted to deliver at least one of water for supplying said geothermal probe and at least one cooling fluid (12) for cooling said drilling head (3);

at least one return pipe (13) which is adapted to return to surface of at least one of said water for supplying said geothermal probe and said cooling fluid (12) together with drilling debris (14);

at least a first supply pipe (15) which is adapted to supply said extruding assembly (6) by means of said polymeric material (16) in a thread-like form; and

at least a second supply pipe (17) which is adapted to allow the passage of cables (18) for the power supply of said motorized means (8).

5) Machine (1) according to one or more of the preceding claims, characterized by the fact that said machine body (2) comprises at least one cavity (19) in which said extruding assembly (6) is housed and defining at least one outlet duct (20) of said piping (7).

6) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises gripping means (9) associated with said machine body (2) and adapted to come into contact with a wall (10) of said hole (5) during the movement of said drilling head (3).

7) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises conveying means (21) adapted to convey said drilling debris (14) into at least one of said return pipe (13) and the space (22) comprised between said pipes (11, 13, 15, 17) and said hole (5).

8) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises connecting means of said geothermal probe adapted to connect said delivery pipe (11) and said return pipe (13) to each other by means of at least one connecting component (26) which is pre-loaded on said machine body (2).

9) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises detection and control means (25, 27) adapted to manage the forward movement of said machine (1) along said direction of drilling (A).

10) Machine (1) according to claim 9, characterized by the fact that said detection and control means (25, 27) comprise at least one detection unit (25) housed on said machine (1) and at least one control unit (27) located at an outer surface (28) which is operatively connected to said detection unit (25) by means of connecting means.