EP2685008B1

EP2685008B1 - Device and method for laying the foundations of a solar collector supporting structure in the ground

Info

Publication number: EP2685008B1
Application number: EP12755656.1A
Authority: EP
Inventors: Elena HERRERA DEL TORO; Teodoro Lopez Del Cerro
Original assignee: Abengoa Solar New Technologies SA
Current assignee: Abengoa Solar New Technologies SA
Priority date: 2011-03-08
Filing date: 2012-03-05
Publication date: 2015-09-16
Anticipated expiration: 2032-03-05
Also published as: ES2562477T3; CN103597142A; ES2400430A2; US20140321922A1; ES2400430R1; EP2685008A1; ES2400430B1; WO2012120174A4; ZA201306707B; EP2685008A4; WO2012120174A1; CL2013002558A1

Description

OBJECT OF THE INVENTION

The present invention can be included in the technical field of solar energy utilisation. More specifically, the object of the invention relates to a device and a method for anchoring a support structure for solar collectors to the ground.

BACKGROUND OF THE INVENTION

In the field of construction, so-called piles are known, used as construction elements used for anchoring structures, allowing loads to be transferred to a resistant soil layer when they are located at a depth such that conventional foundation footings or slabs are rendered technically or economically unfeasible.
In this connection, British Patent GB2360809 relates to a pile and an installation method, disclosing a pile that comprises a rod having at least one helix acting as a screw thread to facilitate the penetration of the rod into the ground, where the helix has a plough-shaped load flank for compressing the ground radially outwards during penetration of the rod. The pile introduction process comprises the incorporation of a bonding agent around the rod during introduction for insertion into a vacuum created by the plough-shaped assembly.
Likewise, British Patent GB2397327 relates to a pile comprising at least two portions axially aligned telescopically in order to fix the effective pile length and comprises fixing means for allowing one of the sections to be fixed to another section in a plurality of positions to selectively determine the total length of the pile.
Specifically, in the field of solar energy, the use of foundation piles for anchoring photovoltaic solar panel structures to the ground is known.
However, the application of the piles to solar concentration structures, for example, of the PTC type (parabolic trough collectors) has drawbacks due to, among other reasons, the high stresses to which the foundations of thermal collectors are subject with respect to photovoltaic collectors. Additionally, fixation using plies entails accuracy requirements that are not within reach of all the systems used.
The problem posed consists of defining means for fixing solar collector structures to foundation piles allowing execution of the fixation in a simple and highly accurate manner.

DESCRIPTION OF THE INVENTION

The present invention describes, according to a first aspect, a device for laying the foundations of a support structure for solar collectors comprising:

at least one pile having a first end adapted for insertion into the ground and a second end projecting from the ground; and
joining means for joining the pile to the structure.

According to a first embodiment of the invention, the joining means for joining the pile to the structure comprise a bolt, attached to the pile by a lower end of the bolt (threaded or not threaded) and attachable to the structure by a threaded upper end opposite the lower end. The lower end of the bolt is, according to this first embodiment, housed and fixed in a body inserted in the second end of the pile (the end projecting from the ground) and fixed to said pile. Preferably, the body is made of hardenable material susceptible of, by drying and/or setting, hardening and adhering to the pile and bolt, such as, for example, cement, concrete or mortar.
A second aspect of the invention relates to a method for anchoring a support structure for solar collectors to the ground, using the device of the invention, which comprises the following steps:

introduction of the first end of the pile in the ground, leaving the second end above the ground; and
fixation of the structure to the outer end of the pile.

When the joining means comprise a bolt, the method can include the additional step of fixing the bolt to the pile.
Therefore, the bolt can be fixed to the pile following the steps below:

defining, on the second end of the pile, a receptacle open at least partially;
disposing and holding the lower end of the bolt in place in the interior of the receptacle, preferably using templates or topographic control;
pouring the hardenable material into the interior of said receptacle; and
allowing the hardenable material to harden.

Alternatively, it is possible to pour the hardenable material first and, subsequently, before said material hardens, insert the lower end of the bolt in said hardenable material.
Preferably, defining a receptacle on the second end of the pile comprises forcibly introducing, to a certain depth, a first watertight elastic plug, preferably of polystyrene foam, having dimensions slightly larger than the cross-section of the second end of the pile, said receptacle being composed of the first plug and by the inner surface of the second end of the pile, above the first plug.
Optionally, the step that involves defining the receptacle may include an additional stage of forcibly introducing to a second depth, less than the first depth, a second watertight elastic plug, preferably of polystyrene foam, having dimensions slightly larger than the cross-section of the second end of the pile, said second plug having a first opening for inserting the bolt and a second opening for pouring the hardenable material. The location of the first opening can be established preferably using templates or topographic control.
In accordance with a second preferred embodiment, the joining means comprise, alternatively to the bolt, a cap disposed tightly around the exterior of the second end of the pile, said cap having first fixing means for fixing the pile to the structure. Preferably, the fixing means comprise a metal bracket having a first side for fixation to the cap and a second side for fixation to the structure. The second side can also be fixed to the structure using bolts or other types of fasteners.
According to a third preferred embodiment, the joining means comprise, in addition to a bolt:

a first plate fixed to the upper part of the second end of the pile having a plurality of first slots; and
a second plate disposed overlying the first plate, having a first bore and second slots (in plan), the directrix of which cuts the directrix of the first slots, and at least partially overlapping the first slots, in order to enable the fixation of the first plate and the second plate in relatively variable positions by means of second fixing means insertable through the first slots and second slots;

Preferably, the first slots and the second slots comprise:

first and second straight slots, the guides of which are straight line segments, preferably in directions extending from the external contour towards the interior of the plates; and
first and second circumferential slots, the directrixes of which are circumference segments, preferably with respect to the centres of the plates;

Therefore, the fixation of the bolt comprises the following steps:

fixing the first plate to the pile;
introducing the lower end of the bolt in the first bolt and fixing said bolt to the second plate;
superimposing the second plate to the first plate, aligning at least partially the first slots with the second slots; and
screwing the first plate to the second plate by introducing the second fixing means through the slots.

In a manner compatible with any of the embodiments described, the joining means may additionally comprise a joining element, preferably a profile, having a flat face, wherein said flat face comprises bores to facilitate the fixation of the piles to the structure, said flat face being adapted for the structure to rest on said flat face.
Optionally, the method explained comprises the additional step of determining the location of the pile with respect to the ground prior to the introduction of said pile in the ground, as well as determining the location, if using bolts, of the bolt with respect to the pile prior to fixing the bolt to the pile. The location of the bolt and/or pile shall be determined preferably using one of the following techniques:

topographic determination and control; and
use of templates having marks indicating the relative locations of the piles and/or the bolts.

The present invention allows anchoring of a support structure for solar collectors to the ground in a fast, accurate and cost-effective manner, simply and cleanly, without need for passage of trucks, cement mixers, etc.

DESCRIPTION OF THE DRAWINGS

In order to complement the description being made and with the object of helping to better understand the characteristics of the invention, in accordance with a preferred embodiment thereof, said description is accompanied, as an integral part thereof, by a set of drawings where, in an illustrative and non-limiting manner, the following has been represented:

Figure 1 shows a sectional view of the device in accordance with the first preferred embodiment.
Figure 2 shows a view of the device in accordance with the second preferred embodiment.
Figure 3a shows a perspective view of the first plate in accordance with the third preferred embodiment.
Figure 3b shows a perspective view of the second plate of the third preferred embodiment.
Figure 3c shows a perspective view of the first plate and the second plate joined together in accordance with the third preferred embodiment.
Figure 3d shows a side view of the joint between the first plate and the second plate.
Figure 4a shows a view of an example of a joint between the pile and the structure by means of a profile.
Figure 4b shows a detailed view of the joint by means of a profile of figure 4a.

PREFERRED EMBODIMENTS OF THE INVENTION

As can be observed in figures 1, 2, 3a, 3b, 3c, 3d, 4a and 4b, the device for anchoring a support structure (2) for solar collectors to the ground (1), in accordance with the invention, comprises: at least one pile (3) having a first end (4) adapted for insertion into the ground (1) and a second end (5) projecting from the ground (1); and joining means for joining the pile (3) to the structure (2). Likewise, the method for anchoring a support structure (2) for solar collectors to the ground (1) using the device of the invention and which comprises the following steps: introduction of the first end (4) of the pile (3) in the ground (1), leaving the second end (5) above the ground (1); and fixation of the structure (2) to the bolt (7).
According to a first embodiment of the invention, as illustrated in figure 1, the joining means for joining the pile (3) to the structure (2) comprise a bolt (7) attached to the pile (3) by a lower end (8) (threaded or not threaded) and attachable to the structure (2) by a threaded upper end (9) opposite the lower end (8).
Continuing with the first embodiment, the method comprises the previous step of fixing the bolt (7) to the pile (3). To this end, the lower end (8) of the bolt (7) is housed in a body (10), formed by mortar, inserted in the second end (5) of the pile (3) and fixed to said pile (3).
Therefore, the bolt (7) can be fixed to the pile (3) by forcibly introducing, prior to the bolt (7), through the second end (5) of the pile (3), a watertight first plug (13) and then a watertight second plug (14), preferably of polystyrene foam, having dimensions slightly larger than those of the cross-section of the second end (5) of the pile (3), defining a receptacle (not shown) between the two plugs (13, 14). Next, a first opening (not shown) and a second opening (12) are made in the second plug (14) and the mortar is poured into the receptacle through the second opening (12), allowing said mortar to harden. The location of the first opening is determined preferably using a template or topographic control. Next, the lower end (8) of the bolt (7) is housed inside said first opening.
In accordance with a second preferred embodiment, as shown in figure 2, the joining means comprise, alternatively to the bolt (7), a cap (30) disposed, preferably in a tight-fitting manner, around the exterior of the second end (5) of the pile (3), said cap (30) having first joining means in the manner of a metal bracket (31) having a first side (32) for fixation to the cap (30) and a second side (33) having a hole for fixation directly to the structure (2). Additionally, the first fixing means may comprise a second bracket (34) comprising a lower bored side (35) resting on the second side (33) and an upper side (36) whereon the structure (2) rests. There is no reason why the first bracket (31) or second bracket (32) cannot be fixed to the structure (2) by means of bolts (not shown).
According to a third preferred embodiment, as can be observed in figures 3a, 3b, 3c and 3d, the joining means comprise, in addition to the bolt (7):

a first plate (18), preferably circular, fixed to the upper part of the second end (5) of the pile (3), having a plurality of first slots (20, 21), as shown in figure 3a;
a second plate (24), preferably circular (see figure 3b), disposed on the first plate (18) (see figures 3c and 3d), having a first bore (not shown) and second slots (22, 23); and
second fixing means (26), preferably screws (see figure 3c), insertable through the first slots (20, 21) and second slots (22, 23) for fixing the first plate (18) to the second plate (24), wherein the bolt (7) passes through the first bore of the second plate (24) and is fixed to the second plate (24).

In the third embodiment, the first slots (20, 21) and the second slots (22, 23) comprise:

straight slots (20, 22), the directrixes of which are straight line segments extending in radial directions with respect to the centres of the plates (18, 24); and
circumferential slots (21, 23), the directrixes of which are concentric circumference segments with respect to the centres of the plates (18, 24);

In accordance with the third embodiment, the fixation of the bolt (7) to the pile (3) comprises the steps of: fixing the first plate (18) to the pile (3); introducing the lower end (8) of the bolt (7) in the first bore of the second plate (24) and fixing said bolt (7) to said second plate (24); superimposing the second plate (24) on the first plate (18), aligning at least partially the first slots (20, 21) with the second slots (22, 23); and screwing the first plate (18) to the second plate (24) by introducing the second fixing means (26) through the slots (20, 21, 22, 23).
In a manner compatible with any of the embodiments described, as can be observed in figures 4a and 4b, the joining means additionally comprise a joining element, preferably a profile (15), having a flat face (29), wherein said flat face (29) comprises second bores (not shown) for facilitating the joint between the piles and the structure; likewise, the flat face (29) is adapted so that the structure (2) rests on said flat face (29). In particular, in the case of use of bolts (7), the second bores serve to house and fix the bolts (7) of two adjacent piles (3).
The method explained comprises the additional step of determining the location of the pile (3) with respect to the ground (1) prior to introducing said pile (3) in the ground (1), as well as determining, when a bolt (7) is used, the location of said bolt (7) with respect to the pile (3) prior to fixing the bolt (7) to the pile (3). The location of the bolt (7) and/or pile (3) can be determined preferably using at least one of the following techniques: topographic determination and control; and use of templates (not shown) having marks indicating the relative locations of the piles (3) and/or the bolts (7).

Claims

A device for anchoring to the ground (1) a support structure (2) for solar collectors, the device comprising:
- at least one pile (3) having a first end (4) adapted for insertion into the ground (1) and a second end (5) for projecting from the ground (1); and

- joining means for joining the pile (3) to the structure (2), the joining means comprising a bolt (7) having: a lower end (8) attached to the pile (3); and a threaded upper end (9) for attaching the bolt (7) to the structure (2);
characterized in further comprising a body (10) inserted in the second end (5) of the pile (3) and fixed to said pile (3), wherein the lower end (8) of the bolt (7) is housed and fixed in the body (10).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 1, characterized in that the body (10) is made of a drying-and/or-setting hardenable material, such as cement, concrete or mortar, for adhering to the pile (3) and to the bolt (7).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, comprising:
- at least one pile (3) having a first end (4) adapted for insertion into the ground (1) and a second end (5) above the ground (1); and

- joining means for joining the pile (3) to the structure (2),
characterized in that the joining means comprise a cap (30) disposed on the exterior of the second end (5) of the pile (3), said cap (30) having first fixing means for fixing said cap (30) to the pile (3) and to the structure (2).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 3, characterized in that the first fixing means comprise a metal bracket (31) having a first side (32) for fixation to the cap (30) and a second side (33) for fixation to the structure (2).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 4, characterized in that the first fixing means additionally comprise a second bracket (34) comprising: a lower bored side (35) resting on the second side (33); and an upper side (36) whereon the structure (2) rests.
A device for anchoring to the ground (1) a support structure (2) for solar collectors, the device comprising:
- at least one pile (3) having a first end (4) adapted for insertion into the ground (1) and a second end (5) for projecting from the ground (1); and

- joining means for joining the pile (3) to the structure (2), the joining means comprising a bolt (7) having: a lower end (8) attached to the pile (3); and a threaded upper end (9) for attaching the bolt (7) to the structure (2); characterized in that the joining means additionally comprise:

- a first plate (18) fixed to the upper part of the second end (5) of the pile (3);

- a plurality of first slots (20, 21), located on the first plate (18);

- a second plate (24) disposed overlying the first plate (18);

- a first bore, located on the second plate (24);

- second slots (22, 23), locating on the second plate (24), and having respective directrixes cutting these of the first slots (20, 21), wherein the second slots (22, 23) at least partially overlap the first slots (20, 21) to allow fixation of the first plate (18) to the second plate (24) in variable relative positions; and

- second fixing means (26), insertable through the first slots (20, 21) and the second slots (22, 23), for fixing the first plate (18) and the second plate (24) to each other, wherein the bolt (7) passes through the first bore of the second plate (24) and is fixed to the second plate (24).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 6, characterized in that the first slots (20, 21) and the second slots (22, 23) comprise:
- straight slots (20, 22), the directrixes of which are straight line segments; and

- circumferential slots (21, 23), the directrixes of which are concentric circumference segments;
where each first straight slot (20) is overlapped by a second circumferential slot (23) and each first circumferential slot (21) is overlapped by a second straight slot (22).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 7, characterized in that the directrixes of the straight slots (20, 22) extend from the external contour toward the interior of the plates (18, 24).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 7, characterized in that the directrixes of the straight slots (20, 22) extend in radial directions with respect to the centres of the plates (18, 24) and the directrixes of the circumferential slots (21, 23) are concentric with respect to said centres.
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to any one of the preceding claims, characterized in that the joining means additionally comprise a joining element, connectable to the support structure (2), and having a flat face (29), wherein said flat face (29) comprises second bores for fixing the piles (3) to the structure (2).
A device for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 10, characterized in that the second bores are adapted for housing and fixing the bolts (7) of two adjacent piles (3).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, using the device described in anyone of claims 1, 2, 10, 11, comprising the following steps:
- introducing in the ground (1) the first end (4) of the pile (3), leaving the second end (5) of the pile (3) projecting above the ground (1); and

- fixing the structure to the second end (5) of the pile (3);
characterized in further comprising a step of fixing the bolt (7) to the pile (3) and to the structure, comprising the following stages:
- defining a receptacle at least partially open on the second end of the pile (3);

- disposing and holding in place the lower end (8) of the bolt (7) in the interior of the receptacle;

- pouring the hardenable material into the interior of said receptacle; and

- allowing the hardenable material to harden.
A method for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 12, characterized in that defining a receptacle comprises the stage of forcibly introducing to a first depth a watertight first elastic plug (13) having dimensions slightly larger than the cross-section of the second end (5) of the pile (3).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 13, characterized in that it comprises the additional step of forcibly introducing to a second depth, less than the first depth, a second watertight elastic plug (14) having dimensions slightly larger than the cross-section of the second end (5) of the pile (3).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, using the device described in anyone of claims 3-5, 10, 11 comprising the following steps:
- introducing in the ground (1) the first end (4) of the pile (3), leaving the second end (5) of the pile (3) projecting above the ground (1); and

- fixing the structure to the second end (5) of the pile (3), using the joining means;
characterized in further comprising a step of fixing the cap (30) to the pile (3) and to the structure (2).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, using the device described in anyone of claims 6-11, comprising the following steps:
- introducing in the ground (1) the first end (4) of the pile (3), leaving the second end (5) of the pile (3) projecting above the ground (1); and

- fixing the structure to the second end (5) of the pile (3);
characterized in further comprising a step of fixing the bolt (7) to the pile (3) and to the structure (2) comprising the following stages:
- fixing the first plate (18) to the second end (5) of the pile (3);

- introducing the lower end (8) of the bolt (7) in the first bore of the second plate (24) and fixing said bolt (7) to said second plate (24);

- superimposing the second plate (24) to the first plate (18), aligning at least partially the first slots (20, 21) with the second slots (22, 23); and

- fixing the first plate (18) to the second plate (24) by introducing the fixing means (26) through the slots (20, 21, 22, 23).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, according to anyone of claims 12-16, characterized in that it comprises the additional steps of:
- determining the location of the pile (3) with respect to the ground (1) prior to introducing said pile (3) in the ground; and / or

- determining the location of the bolt (7) with respect to the pile (3), prior to fixing the bolt (7) to the pile (3).
A method for anchoring to the ground (1) a support structure (2) for solar collectors, according to claim 17, characterized in that the location of the bolt (7) and/or of the pile (3) is determined using at least one of the following techniques:
- topographic determination and control; and

- use of templates having marks indicating the relative locations of the piles (3) and/or the bolts (7).