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Title:
CONCRETE PILE FOR PILE-DRIVING TO FORM A THERMAL SOIL STORAGE
Document Type and Number:
WIPO Patent Application WO/2003/023150
Kind Code:
A1
Abstract:
The invention relates to a concrete pile for pile-driving in soil that is suitable for pile-driving and that is intended for forming a thermal soil storage. The arrangement of heat exchange pipes in soil, that has been provided with or at the same time or later will be provided with piles driven down in the soil involves complications difficult to solve, including theintroduction of different kinds of heavy vehicles intended for the two kinds of working operations. The invention solves this problem and results in that the pile-driving and the arrangement of an efficient soil storage can be carried out at the same time without disturbing each other. This is achieved, according to the invention, by the concrete pile (1) having a centre, axial channel (9), which is heat-insulated in relation to the surrounding concrete, and a large number of axial, peripheral channels (12) close to the outer surface of the concrete pile. The bottom ends of the peripheral channels (12) communicate with a bottom end of the centre channel (9). Th e upper end of the centre channel (9) opens out in an opening (7) in the upper end surface of the concrete pile, in which also an opening (8) to the centre channels (12) is situated.

Inventors:
Platell, Ove (Tilskogsvägen 15 Sigtuna, S-193 40, SE)
Application Number:
PCT/SE2002/001561
Publication Date:
March 20, 2003
Filing Date:
September 02, 2002
Export Citation:
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Assignee:
LOWTE AB (Tilskogsvägen 15 Sigtuna, S-193 40, SE)
Platell, Ove (Tilskogsvägen 15 Sigtuna, S-193 40, SE)
International Classes:
E02D5/30; E02D5/52; F24J3/08; F28D20/00; (IPC1-7): E02D5/30; F24J3/08
Domestic Patent References:
WO2000036343A12000-06-22
Foreign References:
GB2049921A1980-12-31
DE3026638A11982-02-11
CH658513A51986-11-14
Attorney, Agent or Firm:
Waldinger, Åke (Roslinvägen 41 Bromma, S-168 51, SE)
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Claims:
PATENT CLAIMS
1. Concrete pile for piledriving in soil suitable for piledriving to form a thermal soil storage, characterized in that the concrete pile (1) has an axial, centre channel (9) which is heatinsulated in relation to the concrete (17) and which extends from an opening (7) in the upper end surface of the pile to the bottom end portion of the pile, in which portion a bottom end of the centre channel (9) communicates with bottom ends of a great number of axial, peripheral channels (12) which have a small sectional area, are circumferentially distributed with small interspaces close to the outer surface of the concrete pile, and have upper ends connected to an opening (8) in the upper end of the concrete pile, which two openings (7,8) are provided with connection means (18,19) for connection to an exterior flow circuit.
2. Concrete pile according to claim 1, characterized in that at least some of the peripheral channels (12) are attached to axial reinforcing bars (3) present in the concrete pile and situated close to the outer surface of the concrete pile.
3. Concrete pile according to claim 1 or 2, characterized in that the upper end of the concrete pile (1) has a cap (5) provided with a striking surface for facilitating the driving down of the concrete pile into the soil, which cap (5) is provided with the connection means (18,19) for connection of the openings (7,8) of the two types of channels (9, 12, resp. ) to an exterior flow circuit..
4. Concrete pile according to claim 3, characterized in that the cap (5) on the upper end of the concrete pile (1) is provided with a centering means (6,26, 28) for axial fitting together with an extension concrete pile (2) of the same type as the concrete pile (1), but with a bottom end provided with a bottom cap (20) having a centering means (27,29) corresponding to the centering means (6,26, 28) of the concrete pile, and connecting means (21,22) for connection to the connection means (18,19) of the concrete pile (1).
Description:
CONCRETE PILE FOR PILE-DRIVING TO FORM A THERMAL SOIL STORAGE.

The present invention relates to a concrete pile for pile-driving in soil, that is suitable for pile-driving, to form a thermal soil storage.

Concrete piles for pile-driving purposes normally consist of a skeleton of reinforcing bars surrounded by moulded concrete. The bottom end is lined with a conical cap made of steel, and the upper end also has a cap of steel, but formed with a striking surface as well as centering means for axial fitting together with an extension pile having a bottom end formed with a steel cap provided with a centering means corresponding to the centering means of the concrete pile. The pile-driving is made either for stabilization of the soil or for supporting buildings. Especially in the latter case it is often desirable to arrange a thermal soil storage beneath the buildings. This has to be done in connection with the preparing of the soil beneath the prospective buildings by digging down heat exchanger pipes or tubes into the soil, or by drilling deep boreholes in the ground into which heat exchanger pipes are fed down. The pile-driving and the arrangement of a soil storage demands introduction of heavy machines of quite different kinds to the area. Problems like crowding and the use of a mobile pile-driver may result in damages to the installations for the soil storage.

A solution at pile-driving of concrete piles which at the same time results in a possibility of arranging a soil storage beneath a building is known from the SE 7903379-1 and consists of the concrete piles being formed with an axial liner tube in the centre portion of each concrete pile, which liner tube has a closed bottom and into which a preferably heat insulated plastic or rubber tube is introduced, which has a bottom end that is open and communicates with a ring-shaped space between the tube and its possible heat insulation and the liner tube, which space extends up to the upper end of the concrete pile. The object is, after connection of the two legs thus formed to an exterior flow circuit comprising sun panels, to circulate water heated by the sun panels through the two legs for transmitting heat to the surrounding soil. Heat stored in the soil then can be recovered by circulating the water trough some kind of heat emitting apparatus.

Such a concrete pile serves just as a very good concrete pile but extremely bad as a heat exchanger for transmitting heat between the concrete pile and the surrounding soil. With respect to strength demands of the concrete pile, the diameter of the liner tube is very restricted and has been limited to a diameter less than half the diameter of the concrete pile.

Hence, also the space for the heat insulation will be very restricted, which results almost in a thermal short-circuit between the two legs. None the less serious is that the heat transmitting surface consists of the exterior of the liner tube, which owing to the limited diameter of the liner tube presents a limited area and, consquently, a further restricted heat transmitting capacity.

The object of the invention is to achieve a solution of these problems resulting in that pile-driving and the arrangement of an efficient thermal soil storage can be performed without infringing each other.

This is achieved by a concrete pile according to the invention having an axial centre channel which is heat-insulated in relation to the concrete and which extends from an opening in the upper end surface of the pile to the bottom end portion of the pile, in which portion a bottom end of the centre channel communicates with bottom ends of a great number of axial, peripheral channels which each have a small sectional area, are circumferentially distributed with small interspaces close to the outer surface of the concrete pile, and have upper ends connected to an opening in the upper end of the concrete pile. By this is achieved, like in the known embodiment, that when the pile-driving is finished, it is necessary only to connect an exterior circuit to the channel openings of the concrete piles or extension concrete piles, respectively, which openings suitably are provided with connection means, in order to complete the thermal soil storage, but with the important difference that the concrete pile according to the invention results in that the thermal soil storage becomes sufficiently efficient with the number of concrete piles that is required for stabilization of the soil in course of construction. If thermo-technical resons should require a further increase of the number of concrete piles, which probably would be the case with the known embodiment, one has to take into account that the costs would increase to a level that makes the arrangement of a thermal soil storage uneconomical.

The invention will become more apparent in the following with reference to the accompanying drawings showing, by way of example, an embodiment of a concrete pile according to the invention, and in which Figure 1 is a longitudinal section along the line 1-1 in Fig. 2 of the concrete pile and on top of it an extension concrete pile, Figure 2 is a perspective view of the upper end of the concrete pile in Fig. 1, Figure 3 is a cross-sectional view along line III-III in Fig. 1, and Figure 4 is a cross-sectional view along line IV-IV in Fig. 1.

Figure 1 discloses a bottom part and an upper part of the concrete pile 1 according to the invention, and just above this a bottom part and an upper part of an extension concrete pile 2. Both piles are provided with reinforcing bars 3 arranged in the usual way, of which only a part is shown on the drawing. The bottom part of the concrete pile 1 has a conical cap 4 made of steel to which many of the reincorcing bars 3 are welded. Also the upper part of the concrete pile has a cap 5 made of steel which is welded to the reinforcing bars 3. As shown also in Fig. 2 the cap 5 has a heightened centre part 6 in which two openings 7,8 are arranged.

As shown also in Fig. 3 and 4 the opening 7 is connected to an axial channel 9 in the inner of the concrete pile, which axial channel has a bottom part with a radial connection channel 10 leading to an essentially circular bottom distribution channel 11, that is located just inside the outer surface of the concrete pile. A large number of axial channels 12, each with a very small cross-sectional area, extend from the distribution channel 11 upwards to a circular, upper distribution channel 13 from which a radial connection channel 14 extends to an axial, eccentric channel 15, which opens into the opening 8. The channel 9 is enclosed by a heat insulating sleeve 16 which insulates the tube 9 from the channels 12, which are in close thermal connection with the outer surface of the concrete pile. The channels 12 are formed by tubes 12a, which suitably are lashed to reinforcing bars 3, which in the usual, not shown, way form a cage or the like. Spaces between all the channels 12 or groups of the channels 12 are formed to permit passing through of the mortar 17 at the concreting of the concrete pile. The channel 9 has a diameter of 10-25 mm and the channels 12 a diameter of 2-5 mm.

To obtain connection of the channels of the concrete pile to an exterior circuit, such a circuit is possible to connect by two nipples or the like, which are possible to insert into the openings 7 and 8, in which two 0-rings 18,19 are arranged for sealing against the nipples.

A pile driver with a hammer, that is dropped against the upper cap 5, is used at the pile-driving. It is usual to protect the cap against damage and deformations by temporarily placing a muff (not shown), adapted to the top side of the cap, on the cap 5.

If lengthening by adding an extension concrete pile is deemed necessary, the muff is removed and the extension concrete pile is placed on the upper cap 5 of the concrete pile 1.

The extension concrete pile 2 is designed like the concrete pile 1 with the exception for the conical cap 4 of the concrete pile being exchanged for a bottom cap 20 having a bottom surface adapted to the shape of the upper cap 5 of the concrete pile. The cap 5 is provided with two nipples 21 and 22 which fit the openings 7 and 8 in the upper cap 5 of the concrete pile 1, and which are connected to a channel 23 corresponding to channel 9 and a radial connection channel 24, respectively, corresponding to the radial connection channel 10, which channel 24 is connected to a bottom distribution channel 25 corresponding to the distribution channel 11. Besides, like components of the extension concrete pile 2 and the concrete pile 1 are indicated by like reference characters. Hence, the concrete pile 1 as well as the extension concrete pile 2 are provided with a centering stud 26 protruding from the upper cap 5. A corresponding recess 27 is provided in the bottom cap 20 of the extension concrete pile.

Moreover, a centering stud, not visible on the drawings, is protruding from the bottom surface of the bottom cap 20 of the extension concrete pile, with a corresponding recess 28, fig. 2, in the upper caps 5 of the piles 1 and 2. Further, the cap 20 has a recessed center portion 29 corresponding to the heightened center portion 6 of the upper cap 5. The centering studs 26 and the recesses 27,28 are positioned diametrically opposed, such that each extension concrete pile 2 at the lowering towards an underlying pile is properly guided with respect to the nipples 21,22 fitting in the openings 7 and 8, respectively.

Due to the heat insulation of the central, axial channels 9,23 an injurious heat transfer is reduced between said channels and the peripheral, axial channels 12, and due to the placing of the peripheral, axial channels 12 close to the outer sides of the piles 1,2 a largest possible area is obtained and, accordingly, the best possible heat exchange between said channels 12 and the surrounding soil is obtained.

The invention is of course not limited to the embodiment shown and described here by way of example but can be modified in different ways within the scope of the invention defined by the claims. Especially the placing of the channels 9,23 and 12, as well as the design of the distribution channels 11, 13 and 25 and the connection channels 10, 14 and 24 can be varied without influencing the operating essentially.